ROLE OF MANGANESE REDUCTION/OXIDATION (REDOX) ON FOAMING AND MELT RATE IN HIGH LEVEL WASTE (HLW) MELTERS (U)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C; Michael Stone, M

2007-03-30

High-level nuclear waste is being immobilized at the Savannah River Site (SRS) by vitrification into borosilicate glass at the Defense Waste Processing Facility (DWPF). Control of the Reduction/Oxidation (REDOX) equilibrium in the DWPF melter is critical for processing high level liquid wastes. Foaming, cold cap roll-overs, and off-gas surges all have an impact on pouring and melt rate during processing of high-level waste (HLW) glass. All of these phenomena can impact waste throughput and attainment in Joule heated melters such as the DWPF. These phenomena are caused by gas-glass disequilibrium when components in the melter feeds convert to glass andmore » liberate gases such as H{sub 2}O vapor (steam), CO{sub 2}, O{sub 2}, H{sub 2}, NO{sub x}, and/or N{sub 2}. During the feed-to-glass conversion in the DWPF melter, multiple types of reactions occur in the cold cap and in the melt pool that release gaseous products. The various gaseous products can cause foaming at the melt pool surface. Foaming should be avoided as much as possible because an insulative layer of foam on the melt surface retards heat transfer to the cold cap and results in low melt rates. Uncontrolled foaming can also result in a blockage of critical melter or melter off-gas components. Foaming can also increase the potential for melter pressure surges, which would then make it difficult to maintain a constant pressure differential between the DWPF melter and the pour spout. Pressure surges can cause erratic pour streams and possible pluggage of the bellows as well. For these reasons, the DWPF uses a REDOX strategy and controls the melt REDOX between 0.09 {le} Fe{sup 2+}/{summation}Fe {le} 0.33. Controlling the DWPF melter at an equilibrium of Fe{sup +2}/{summation}Fe {le} 0.33 prevents metallic and sulfide rich species from forming nodules that can accumulate on the floor of the melter. Control of foaming, due to deoxygenation of manganic species, is achieved by converting oxidized MnO{sub 2} or Mn{sub 2}O{sub 3} species to MnO during melter preprocessing. At the lower redox limit of Fe{sup +2}/{summation}Fe {approx} 0.09 about 99% of the Mn{sup +4}/Mn{sup +3} is converted to Mn{sup +2}. Therefore, the lower REDOX limits eliminates melter foaming from deoxygenation.« less

Defense waste processing facility (DWPF) liquids model: revisions for processing higher TIO 2 containing glasses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C. M.; Edwards, T. B.; Trivelpiece, C. L.

Radioactive high level waste (HLW) at the Savannah River Site (SRS) has successfully been vitrified into borosilicate glass in the Defense Waste Processing Facility (DWPF) since 1996. Vitrification requires stringent product/process (P/P) constraints since the glass cannot be reworked once it is poured into ten foot tall by two foot diameter canisters. A unique “feed forward” statistical process control (SPC) was developed for this control rather than statistical quality control (SQC). In SPC, the feed composition to the DWPF melter is controlled prior to vitrification. In SQC, the glass product would be sampled after it is vitrified. Individual glass property-compositionmore » models form the basis for the “feed forward” SPC. The models transform constraints on the melt and glass properties into constraints on the feed composition going to the melter in order to guarantee, at the 95% confidence level, that the feed will be processable and that the durability of the resulting waste form will be acceptable to a geologic repository. This report documents the development of revised TiO 2, Na 2O, Li 2O and Fe 2O 3 coefficients in the SWPF liquidus model and revised coefficients (a, b, c, and d).« less

The Impact Of The MCU Life Extension Solvent On Sludge Batch 8 Projected Operating Windows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peeler, D. K.; Edwards, T. B.

2013-06-26

As a part of the Actinide Removal Process (ARP)/Modular Caustic Side Solvent Extraction Unit (MCU) Life Extension Project, a next generation solvent (NGS) and a new strip acid will be deployed. The strip acid will be changed from dilute nitric acid to dilute boric acid (0.01 M). Because of these changes, experimental testing or evaluations with the next generation solvent are required to determine the impact of these changes (if any) to Chemical Process Cell (CPC) activities, glass formulation strategies, and melter operations at the Defense Waste Processing Facility (DWPF). The introduction of the dilute (0.01 M) boric acid streammore » into the DWPF flowsheet has a potential impact on glass formulation and frit development efforts since B203 is a major oxide in frits developed for DWPF. Prior knowledge of this stream can be accounted for during frit development efforts but that was not the case for Sludge Batch 8 (SB8). Frit 803 has already been recommended and procured for SB8 processing; altering the frit to account for the incoming boron from the strip effluent (SE) is not an option for SB8. Therefore, the operational robustness of Frit 803 to the introduction of SE including its compositional tolerances (i.e., up to 0.0125M boric acid) is of interest and was the focus of this study. The primary question to be addressed in the current study was: What is the impact (if any) on the projected operating windows for the Frit 803 - SB8 flowsheet to additions of B203 from the SE in the Sludge Receipt and Adjustment Tank (SRAT)? More specifically, will Frit 803 be robust to the potential compositional changes occurring in the SRAT due to sludge variation, varying additions of ARP and/or the introduction of SE by providing access to waste loadings (WLs) of interest to DWPF? The Measurement Acceptability Region (MAR) results indicate there is very little, if any, impact on the projected operating windows for the Frit 803 - SB8 system regardless of the presence or absence of ARP and SE (up to 2 wt% B203 contained in the SRAT and up to 2000 gallons of ARP). It should be noted that 0.95 wt% B203 is the nominal projected concentration in the SRAT based on a 0.0125M boric acid flowsheet with 70,000 liters of SE being added to the SRAT.« less

Defense Waste Processing Facility (DWPF) Durability-Composition Models and the Applicability of the Associated Reduction of Constraints (ROC) Criteria for High TiO 2 Containing Glasses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C. M.; Edwards, T. B.; Trivelpiece, C. L.

Radioactive high-level waste (HLW) at the Savannah River Site (SRS) has successfully been vitrified into borosilicate glass in the DWPF since 1996. Vitrification requires stringent product/process (P/P) constraints since the glass cannot be reworked once it has been poured into ten foot tall by two foot diameter canisters. A unique “feed forward” statistical process control (SPC) was developed for this control rather than relying on statistical quality control (SQC). In SPC, the feed composition to the DWPF melter is controlled prior to vitrification. In SQC, the glass product would be sampled after it is vitrified. Individual glass property-composition models formmore » the basis for the “feed forward” SPC. The models transform constraints on the melt and glass properties into constraints on the feed composition going to the melter in order to determine, at the 95% confidence level, that the feed will be processable and that the durability of the resulting waste form will be acceptable to a geologic repository. The DWPF SPC system is known as the Product Composition Control System (PCCS). One of the process models within PCCS is known as the Thermodynamic Hydration Energy Reaction MOdel (THERMO™). The DWPF will soon be receiving increased concentrations of TiO 2-, Na 2O-, and Cs 2O-enriched wastes from the Salt Waste Processing Facility (SWPF). The SWPF has been built to pretreat the high-curie fraction of the salt waste to be removed from the HLW tanks in the F- and H-Area Tank Farms at the SRS. In order to validate the existing TiO 2 term in THERMO™ beyond 2.0 wt% in the DWPF, new durability data were developed over the target range of 2.00 to 6.00 wt% TiO 2 and evaluated against the 1995 durability model. The durability was measured by the 7-day Product Consistency Test. This study documents the adequacy of the existing THERMO™ terms. It is recommended that the modified THERMO™ durability models and the modified property acceptable region limits for the durability constraints be incorporated in the next revision of the technical bases for PCCS and then implemented into PCCS. It is also recommended that an reduction of constraints of 4 wt% Al 2O 3 be implemented with no restrictions on the amount of alkali in the glass for TiO 2 values ≥2 wt%. The ultimate limit on the amount of TiO 2 that can be accommodated from SWPF will be determined by the three PCCS models, the waste composition of a given sludge batch, the waste loading of the sludge batch, and the frit used for vitrification.« less

Defining And Characterizing Sample Representativeness For DWPF Melter Feed Samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shine, E. P.; Poirier, M. R.

2013-10-29

Representative sampling is important throughout the Defense Waste Processing Facility (DWPF) process, and the demonstrated success of the DWPF process to achieve glass product quality over the past two decades is a direct result of the quality of information obtained from the process. The objective of this report was to present sampling methods that the Savannah River Site (SRS) used to qualify waste being dispositioned at the DWPF. The goal was to emphasize the methodology, not a list of outcomes from those studies. This methodology includes proven methods for taking representative samples, the use of controlled analytical methods, and datamore » interpretation and reporting that considers the uncertainty of all error sources. Numerous sampling studies were conducted during the development of the DWPF process and still continue to be performed in order to evaluate options for process improvement. Study designs were based on use of statistical tools applicable to the determination of uncertainties associated with the data needs. Successful designs are apt to be repeated, so this report chose only to include prototypic case studies that typify the characteristics of frequently used designs. Case studies have been presented for studying in-tank homogeneity, evaluating the suitability of sampler systems, determining factors that affect mixing and sampling, comparing the final waste glass product chemical composition and durability to that of the glass pour stream sample and other samples from process vessels, and assessing the uniformity of the chemical composition in the waste glass product. Many of these studies efficiently addressed more than one of these areas of concern associated with demonstrating sample representativeness and provide examples of statistical tools in use for DWPF. The time when many of these designs were implemented was in an age when the sampling ideas of Pierre Gy were not as widespread as they are today. Nonetheless, the engineers and statisticians used carefully thought out designs that systematically and economically provided plans for data collection from the DWPF process. Key shared features of the sampling designs used at DWPF and the Gy sampling methodology were the specification of a standard for sample representativeness, an investigation that produced data from the process to study the sampling function, and a decision framework used to assess whether the specification was met based on the data. Without going into detail with regard to the seven errors identified by Pierre Gy, as excellent summaries are readily available such as Pitard [1989] and Smith [2001], SRS engineers understood, for example, that samplers can be biased (Gy's extraction error), and developed plans to mitigate those biases. Experiments that compared installed samplers with more representative samples obtained directly from the tank may not have resulted in systematically partitioning sampling errors into the now well-known error categories of Gy, but did provide overall information on the suitability of sampling systems. Most of the designs in this report are related to the DWPF vessels, not the large SRS Tank Farm tanks. Samples from the DWPF Slurry Mix Evaporator (SME), which contains the feed to the DWPF melter, are characterized using standardized analytical methods with known uncertainty. The analytical error is combined with the established error from sampling and processing in DWPF to determine the melter feed composition. This composition is used with the known uncertainty of the models in the Product Composition Control System (PCCS) to ensure that the wasteform that is produced is comfortably within the acceptable processing and product performance region. Having the advantage of many years of processing that meets the waste glass product acceptance criteria, the DWPF process has provided a considerable amount of data about itself in addition to the data from many special studies. Demonstrating representative sampling directly from the large Tank Farm tanks is a difficult, if not unsolvable enterprise due to limited accessibility. However, the consistency and the adequacy of sampling and mixing at SRS could at least be studied under the controlled process conditions based on samples discussed by Ray and others [2012a] in Waste Form Qualification Report (WQR) Volume 2 and the transfers from Tanks 40H and 51H to the Sludge Receipt and Adjustment Tank (SRAT) within DWPF. It is important to realize that the need for sample representativeness becomes more stringent as the material gets closer to the melter, and the tanks within DWPF have been studied extensively to meet those needs.« less

DWPF Safely Dispositioning Liquid Waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2016-01-05

The only operating radioactive waste glassification plant in the nation, the Defense Waste Processing Facility (DWPF) converts the liquid radioactive waste currently stored at the Savannah River Site (SRS) into a solid glass form suitable for long-term storage and disposal. Scientists have long considered this glassification process, called “vitrification,” as the preferred option for treating liquid radioactive waste.

DWPF Safely Dispositioning Liquid Waste

ScienceCinema

None

2018-06-21

The only operating radioactive waste glassification plant in the nation, the Defense Waste Processing Facility (DWPF) converts the liquid radioactive waste currently stored at the Savannah River Site (SRS) into a solid glass form suitable for long-term storage and disposal. Scientists have long considered this glassification process, called “vitrification,” as the preferred option for treating liquid radioactive waste.

EVALUATION OF THE IMPACT OF THE DEFENSE WASTE PROCESSING FACILITY (DWPF) LABORATORY GERMANIUM OXIDE USE ON RECYCLE TRANSFERS TO THE H-TANK FARM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C.; Laurinat, J.

2011-08-15

When processing High Level Waste (HLW) glass, the Defense Waste Processing Facility (DWPF) cannot wait until the melt or waste glass has been made to assess its acceptability, since by then no further changes to the glass composition and acceptability are possible. Therefore, the acceptability decision is made on the upstream feed stream, rather than on the downstream melt or glass product. This strategy is known as 'feed forward statistical process control.' The DWPF depends on chemical analysis of the feed streams from the Sludge Receipt and Adjustment Tank (SRAT) and the Slurry Mix Evaporator (SME) where the frit plusmore » adjusted sludge from the SRAT are mixed. The SME is the last vessel in which any chemical adjustments or frit additions can be made. Once the analyses of the SME product are deemed acceptable, the SME product is transferred to the Melter Feed Tank (MFT) and onto the melter. The SRAT and SME analyses have been analyzed by the DWPF laboratory using a 'Cold Chemical' method but this dissolution did not adequately dissolve all the elemental components. A new dissolution method which fuses the SRAT or SME product with cesium nitrate (CsNO{sub 3}), germanium (IV) oxide (GeO{sub 2}) and cesium carbonate (Cs{sub 2}CO{sub 3}) into a cesium germanate glass at 1050 C in platinum crucibles has been developed. Once the germanium glass is formed in that fusion, it is readily dissolved by concentrated nitric acid (about 1M) to solubilize all the elements in the SRAT and/or SME product for elemental analysis. When the chemical analyses are completed the acidic cesium-germanate solution is transferred from the DWPF analytic laboratory to the Recycle Collection Tank (RCT) where the pH is increased to {approx}12 M to be released back to the tank farm and the 2H evaporator. Therefore, about 2.5 kg/yr of GeO{sub 2}/year will be diluted into 1.4 million gallons of recycle. This 2.5 kg/yr of GeO{sub 2} may increase to 4 kg/yr when improvements are implemented to attain an annual canister production goal of 400 canisters. Since no Waste Acceptance Criteria (WAC) exists for germanium in the Tank Farm, the Effluent Treatment Project, or the Saltstone Production Facility, DWPF has requested an evaluation of the fate of the germanium in the caustic environment of the RCT, the 2H evaporator, and the tank farm. This report evaluates the effect of the addition of germanium to the tank farm based on: (1) the large dilution of Ge in the RCT and tank farm; (2) the solubility of germanium in caustic solutions (pH 12-13); (3) the potential of germanium to precipitate as germanium sodalites in the 2H Evaporator; and (4) the potential of germanium compounds to precipitate in the evaporator feed tank. This study concludes that the impacts of transferring up to 4 kg/yr germanium to the RCT (and subsequently the 2H evaporator feed tank and the 2H evaporator) results in <2 ppm per year (1.834 mg/L) which is the maximum instantaneous concentration expected from DWPF. This concentration is insignificant as most sodium germanates are soluble at the high pH of the feed tank and evaporator solutions. Even if sodium aluminosilicates form in the 2H evaporator, the Ge will likely substitute for some small amount of the Si in these structures and will be insignificant. It is recommended that the DWPF continue with their strategy to add germanium as a laboratory chemical to Attachment 8.2 of the DWPF Waste Compliance Plan (WCP).« less

Material compatibility evaluation for DWPF nitric-glycolic acid-literature review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mickalonis, J.; Skidmore, E.

2013-06-01

Glycolic acid is being evaluated as an alternative for formic and nitric acid in the DWPF flowsheet. Demonstration testing and modeling for this new flowsheet has shown that glycolic acid and glycolate has a potential to remain in certain streams generated during the production of the nuclear waste glass. A literature review was conducted to assess the impact of glycolic acid on the corrosion of the materials of construction for the DWPF facility as well as facilities downstream which may have residual glycolic acid and glycolates present. The literature data was limited to solutions containing principally glycolic acid.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peeler, D; Tommy Edwards, T; Kevin Fox, K

The Savannah River National Laboratory (SRNL) has developed, and continues to enhance, its integrated capability to evaluate the impact of proposed sludge preparation plans on the Defense Waste Processing Facility's (DWPF's) operation. One of the components of this integrated capability focuses on frit development which identifies a viable frit or frits for each sludge option being contemplated for DWPF processing. A frit is considered viable if its composition allows for economic fabrication and if, when it is combined with the sludge option under consideration, the DWPF property/composition models (the models of DWPF's Product Composition Control System (PCCS)) indicate that themore » combination has the potential for an operating window (a waste loading (WL) interval over which the sludge/frit glass system satisfies processability and durability constraints) that would allow DWPF to meet its goals for waste loading and canister production. This report documents the results of SRNL's efforts to identify candidate frit compositions and corresponding predicted operating windows (defined in terms of WL intervals) for the February 2007 compositional projection of Sludge Batch 4 (SB4) developed by the Liquid Waste Organization (LWO). The nominal compositional projection was used to assess projected operating windows (in terms of a waste loading interval over which all predicted properties were classified as acceptable) for various frits, evaluate the applicability of the 0.6 wt% SO{sub 4}{sup =} PCCS limit to the glass systems of interest, and determine the impact (or lack thereof) to the previous SB4 variability studies. It should be mentioned that the information from this report will be coupled with assessments of melt rate to recommend a frit for SB4 processing. The results of this paper study suggest that candidate frits are available to process the nominal SB4 composition over attractive waste loadings of interest to DWPF. Specifically, two primary candidate frits for SB4 processing, Frit 510 and Frit 418, have projected operating windows that should allow for successful processing at DWPF. While Frit 418 has been utilized at DWPF, Frit 510 is a higher B{sub 2}O{sub 3} based frit which could lead to improvements in melt rate. These frits provide relatively large operating windows and demonstrate robustness to possible sludge compositional variation while avoiding potential nepheline formation issues. In addition, assessments of SO{sub 4}{sup =} solubility indicate that the 0.6 wt% SO{sub 4}{sup =} limit in PCCS is applicable for the Frit 418 and the Frit 510 based SB4 glass systems.« less

SLURRY MIX EVAPORATOR BATCH ACCEPTABILITY AND TEST CASES OF THE PRODUCT COMPOSITION CONTROL SYSTEM WITH THORIUM AS A REPORTABLE ELEMENT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, T.

2010-10-07

The Defense Waste Processing Facility (DWPF), which is operated by Savannah River Remediation, LLC (SRR), has recently begun processing Sludge Batch 6 (SB6) by combining it with Frit 418 at a nominal waste loading (WL) of 36%. A unique feature of the SB6/Frit 418 glass system, as compared to the previous glass systems processed in DWPF, is that thorium will be a reportable element (i.e., concentrations of elemental thorium in the final glass product greater than 0.5 weight percent (wt%)) for the resulting wasteform. Several activities were initiated based upon this unique aspect of SB6. One of these was anmore » investigation into the impact of thorium on the models utilized in DWPF's Product Composition and Control System (PCCS). While the PCCS is described in more detail below, for now note that it is utilized by Waste Solidification Engineering (WSE) to evaluate the acceptability of each batch of material in the Slurry Mix Evaporator (SME) before this material is passed on to the melter. The evaluation employs models that predict properties associated with processability and product quality from the composition of vitrified samples of the SME material. The investigation of the impact of thorium on these models was conducted by Peeler and Edwards [1] and led to a recommendation that DWPF can process the SB6/Frit 418 glass system with ThO{sub 2} concentrations up to 1.8 wt% in glass. Questions also arose regarding the handling of thorium in the SME batch acceptability process as documented by Brown, Postles, and Edwards [2]. Specifically, that document is the technical bases of PCCS, and while Peeler and Edwards confirmed the reliability of the models, there is a need to confirm that the current implementation of DWPF's PCCS appropriately handles thorium as a reportable element. Realization of this need led to a Technical Task Request (TTR) prepared by Bricker [3] that identified some specific SME-related activities that the Savannah River National Laboratory (SRNL) was requested to conduct. SRNL issued a Task Technical and Quality Assurance (TT&QA) plan [4] in response to the SRR request. The conclusions provided in this report are that no changes need to be made to the SME acceptability process (i.e., no modifications to WSRC-TR-95-00364, Revision 5, are needed) and no changes need to be made to the Product Composition Control System (PCCS) itself (i.e. the spreadsheet utilized by Waste Solidification Engineering (WSE) for acceptability decisions does not require modification) in response to thorium becoming a reportable element for DWPF operations. In addition, the inputs and results for the two test cases requested by WSE for use in confirming the successful activation of thorium as a reportable element for DWPF operations during the processing of SB6 are presented in this report.« less

THE IMPACT OF THE MCU LIFE EXTENSION SOLVENT ON DWPF GLASS FORMULATION EFFORTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peeler, D; Edwards, T

2011-03-24

As a part of the Actinide Removal Process (ARP)/Modular Caustic Side Solvent Extraction Unit (MCU) Life Extension Project, a next generation solvent (NG-CSSX), a new strip acid, and modified monosodium titanate (mMST) will be deployed. The strip acid will be changed from dilute nitric acid to dilute boric acid (0.01 M). Because of these changes, experimental testing with the next generation solvent and mMST is required to determine the impact of these changes in 512-S operations as well as Chemical Process Cell (CPC), Defense Waste Processing Facility (DWPF) glass formulation activities, and melter operations at DWPF. To support programmatic objectives,more » the downstream impacts of the boric acid strip effluent (SE) to the glass formulation activities and melter operations are considered in this study. More specifically, the impacts of boric acid additions to the projected SB7b operating windows, potential impacts to frit production temperatures, and the potential impact of boron volatility are evaluated. Although various boric acid molarities have been reported and discussed, the baseline flowsheet used to support this assessment was 0.01M boric acid. The results of the paper study assessment indicate that Frit 418 and Frit 418-7D are robust to the implementation of the 0.01M boric acid SE into the SB7b flowsheet (sludge-only or ARP-added). More specifically, the projected operating windows for the nominal SB7b projections remain essentially constant (i.e., 25-43 or 25-44% waste loading (WL)) regardless of the flowsheet options (sludge-only, ARP added, and/or the presence of the new SE). These results indicate that even if SE is not transferred to the Sludge Receipt and Adjustment Tank (SRAT), there would be no need to add boric acid (from a trim tank) to compositionally compensate for the absence of the boric acid SE in either a sludge-only or ARP-added SB7b flowsheet. With respect to boron volatility, the Measurement Acceptability Region (MAR) assessments also suggest that Slurry Mix Evaporator (SME) acceptability decisions would not be different assuming either 100% of the B{sub 2}O{sub 3} from the SE were retained or volatilized. More specifically, the 0.84 wt% B{sub 2}O{sub 3} in the SE is so minor that its presence in the SME analysis does not influence SME acceptability decisions. In fact, using the 100% retention and 100% volatilization composition projections, only minor differences in the predicted properties of the glass product occur with all of the glasses being acceptable over a WL interval of 32-42%. Based on the 0.01M boric acid flowsheet, there is very little difference between Frit 418 and Frit 418-7D (a frit that was compositionally altered to account for the 0.84 wt% B{sub 2}O{sub 3} in the SE) with respect to melt temperature. In fact, when one evaluates the composition of Frit 418-7D, it lies within the current Frit 418 vendor specifications and therefore could have been produced by the vendor targeting the nominal composition of Frit 418.« less

YIELD STRESS REDUCTION OF DWPF MELTER FEED SLURRIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, M; Michael02 Smith, M

2006-12-28

The Defense Waste Processing Facility (DWPF) at the Savannah River Site vitrifies High Level Waste for repository internment. The process consists of three major steps: waste pretreatment, vitrification, and canister decontamination/sealing. The HLW consists of insoluble metal hydroxides (primarily iron, aluminum, magnesium, manganese, and uranium) and soluble sodium salts (carbonate, hydroxide, nitrite, nitrate, sulfate). The pretreatment process acidifies the sludge with nitric and formic acids, adds the glass formers as glass frit, then concentrates the resulting slurry to approximately 50 weight percent (wt%) total solids. This slurry is fed to the joule-heated melter where the remaining water is evaporated followedmore » by calcination of the solids and conversion to glass. The Savannah River National Laboratory (SRNL) is currently assisting DWPF efforts to increase throughput of the melter. As part of this effort, SRNL has investigated methods to increase the solids content of the melter feed to reduce the heat load required to complete the evaporation of water and allow more of the energy available to calcine and vitrify the waste. The process equipment in the facility is fixed and cannot process materials with high yield stresses, therefore increasing the solids content will require that the yield stress of the melter feed slurries be reduced. Changing the glass former added during pretreatment from an irregularly shaped glass frit to nearly spherical beads was evaluated. The evaluation required a systems approach which included evaluations of the effectiveness of beads in reducing the melter feed yield stress as well as evaluations of the processing impacts of changing the frit morphology. Processing impacts of beads include changing the settling rate of the glass former (which effects mixing and sampling of the melter feed slurry and the frit addition equipment) as well as impacts on the melt behavior due to decreased surface area of the beads versus frit. Beads were produced from the DWPF process frit by fire polishing. The frit was allowed to free fall through a flame, then quenched with a water spray. Approximately 90% of the frit was converted to beads by this process, as shown in Figure 1. Borosilicate beads of various diameters were also procured for initial testing.« less

REDUCTION OF CONSTRAINTS FOR COUPLED OPERATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raszewski, F.; Edwards, T.

2009-12-15

The homogeneity constraint was implemented in the Defense Waste Processing Facility (DWPF) Product Composition Control System (PCCS) to help ensure that the current durability models would be applicable to the glass compositions being processed during DWPF operations. While the homogeneity constraint is typically an issue at lower waste loadings (WLs), it may impact the operating windows for DWPF operations, where the glass forming systems may be limited to lower waste loadings based on fissile or heat load limits. In the sludge batch 1b (SB1b) variability study, application of the homogeneity constraint at the measurement acceptability region (MAR) limit eliminated muchmore » of the potential operating window for DWPF. As a result, Edwards and Brown developed criteria that allowed DWPF to relax the homogeneity constraint from the MAR to the property acceptance region (PAR) criterion, which opened up the operating window for DWPF operations. These criteria are defined as: (1) use the alumina constraint as currently implemented in PCCS (Al{sub 2}O{sub 3} {ge} 3 wt%) and add a sum of alkali constraint with an upper limit of 19.3 wt% ({Sigma}M{sub 2}O < 19.3 wt%), or (2) adjust the lower limit on the Al{sub 2}O{sub 3} constraint to 4 wt% (Al{sub 2}O{sub 3} {ge} 4 wt%). Herman et al. previously demonstrated that these criteria could be used to replace the homogeneity constraint for future sludge-only batches. The compositional region encompassing coupled operations flowsheets could not be bounded as these flowsheets were unknown at the time. With the initiation of coupled operations at DWPF in 2008, the need to revisit the homogeneity constraint was realized. This constraint was specifically addressed through the variability study for SB5 where it was shown that the homogeneity constraint could be ignored if the alumina and alkali constraints were imposed. Additional benefit could be gained if the homogeneity constraint could be replaced by the Al{sub 2}O{sub 3} and sum of alkali constraint for future coupled operations processing based on projections from Revision 14 of the High Level Waste (HLW) System Plan. As with the first phase of testing for sludge-only operations, replacement of the homogeneity constraint with the alumina and sum of alkali constraints will ensure acceptable product durability over the compositional region evaluated. Although these study glasses only provide limited data in a large compositional region, the approach and results are consistent with previous studies that challenged the homogeneity constraint for sludge-only operations. That is, minimal benefit is gained by imposing the homogeneity constraint if the other PCCS constraints are satisfied. The normalized boron releases of all of the glasses are well below the Environmental Assessment (EA) glass results, regardless of thermal history. Although one of the glasses had a normalized boron release of approximately 10 g/L and was not predictable, the glass is still considered acceptable. This particular glass has a low Al{sub 2}O{sub 3} concentration, which may have attributed to the anomalous behavior. Given that poor durability has been previously observed in other glasses with low Al{sub 2}O{sub 3} and Fe{sub 2}O{sub 3} concentrations, including the sludge-only reduction of constraints study, further investigations appear to be warranted. Based on the results of this study, it is recommended that the homogeneity constraint (in its entirety with the associated low frit/high frit constraints) be eliminated for coupled operations as defined by Revision 14 of the HLW System Plan with up to 2 wt% TiO{sub 2}. The use of the alumina and sum of alkali constraints should be continued along with the variability study to determine the predictability of the current durability models and/or that the glasses are acceptable with respect to durability. The use of a variability study for each batch is consistent with the glass product control program and it will help to assess new streams or compositional changes. It is also recommended that the influence of alumina and alkali on durability be studied in greater detail. Limited data suggests that there may be a need to adjust the lower Al{sub 2}O{sub 3} limit and/or the upper alkali limit in order to prevent the fabrication of unacceptable glasses. An in-depth evaluation of all previous data as well as any new data would help to better define an alumina and alkali combination that would avoid potential phase separation and ensure glass durability.« less

Corrosion Testing of Monofrax K-3 Refractory in Defense Waste Processing Facility (DWPF) Alternate Reductant Feeds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, M.; Jantzen, C.; Burket, P.

The Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS) uses a combination of reductants and oxidants while converting high level waste (HLW) to a borosilicate waste form. A reducing flowsheet is maintained to retain radionuclides in their reduced oxidation states which promotes their incorporation into borosilicate glass. For the last 20 years of processing, the DWPF has used formic acid as the main reductant and nitric acid as the main oxidant. During reaction in the Chemical Process Cell (CPC), formate and formic acid release measurably significant H 2 gas which requires monitoring of certain vessel’s vapor spaces.more » A switch to a nitric acid-glycolic acid (NG) flowsheet from the nitric-formic (NF) flowsheet is desired as the NG flowsheet releases considerably less H 2 gas upon decomposition. This would greatly simplify DWPF processing from a safety standpoint as close monitoring of the H 2 gas concentration could become less critical. In terms of the waste glass melter vapor space flammability, the switch from the NF flowsheet to the NG flowsheet showed a reduction of H 2 gas production from the vitrification process as well. Due to the positive impact of the switch to glycolic acid determined on the flammability issues, evaluation of the other impacts of glycolic acid on the facility must be examined.« less

Material Compatibility Evaluation for DWPF Nitric-Glycolic Acid - Literature Review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mickalonis, J. I.; Skidmore, T. E.

Glycolic acid is being evaluated as an alternative for formic and nitric acid in the DWPF flowsheet. Demonstration testing and modeling for this new flowsheet has shown that glycolic acid and glycolate has a potential to remain in certain streams generated during the production of the nuclear waste glass. A literature review was conducted to assess the impact of glycolic acid on the corrosion of the materials of construction for the DWPF facility as well as facilities downstream which may have residual glycolic acid and glycolates present. The literature data was limited to solutions containing principally glycolic acid. The reportedmore » corrosion rates and degradation characteristics have shown the following for the materials of construction.« less

Preliminary analysis of species partitioning in the DWPF melter. Sludge batch 7A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, A. S.; Smith III, F. G.; McCabe, D. J.

2017-01-01

The work described in this report is preliminary in nature since its goal was to demonstrate the feasibility of estimating the off-gas carryover from the Defense Waste Processing Facility (DWPF) melter based on a simple mass balance using measured feed and glass pour stream (PS) compositions and time-averaged melter operating data over the duration of one canister-filling cycle. The DWPF has been in radioactive operation for over 20 years processing a wide range of high-level waste (HLW) feed compositions under varying conditions such as bubbled vs. non-bubbled and feeding vs. idling. So it is desirable to find out how themore » varying feed compositions and operating parameters would have impacted the off-gas entrainment. However, the DWPF melter is not equipped with off-gas sampling or monitoring capabilities, so it is not feasible to measure off-gas entrainment rates directly. The proposed method provides an indirect way of doing so.« less

Sludge Washing and Demonstration of the DWPF Nitric/Formic Flowsheet in the SRNL Shielded Cells for Sludge Batch 9 Qualification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pareizs, J.; Newell, D.; Martino, C.

Savannah River National Laboratory (SRNL) was requested by Savannah River Remediation (SRR) to qualify the next batch of sludge – Sludge Batch 9 (SB9). Current practice is to prepare sludge batches in Tank 51 by transferring sludge to Tank 51 from other tanks. The sludge is washed and transferred to Tank 40, the current Defense Waste Process Facility (DWPF) feed tank. Prior to sludge transfer from Tank 51 to Tank 40, the Tank 51 sludge must be qualified. SRNL qualifies the sludge in multiple steps. First, a Tank 51 sample is received, then characterized, washed, and again characterized. SRNL thenmore » demonstrates the DWPF Chemical Process Cell (CPC) flowsheet with the sludge. The final step of qualification involves chemical durability measurements of glass fabricated in the DWPF CPC demonstrations. In past sludge batches, SRNL had completed the DWPF demonstration with Tank 51 sludge. For SB9, SRNL has been requested to process a blend of Tank 51 and Tank 40 at a targeted ratio of 44% Tank 51 and 56% Tank 40 on an insoluble solids basis.« less

Interim glycol flowsheet reduction/oxidation (redox) model for the Defense Waste Processing Facility (DWPF)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C. M.; Williams, M. S.; Zamecnik, J. R.

Control of the REDuction/OXidation (REDOX) state of glasses containing high concentrations of transition metals, such as High Level Waste (HLW) glasses, is critical in order to eliminate processing difficulties caused by overly reduced or overly oxidized melts. Operation of a HLW melter at Fe +2/ΣFe ratios of between 0.09 and 0.33, a range which is not overly oxidizing or overly reducing, helps retain radionuclides in the melt, i.e. long-lived radioactive 99Tc species in the less volatile reduced Tc 4+ state, 104Ru in the melt as reduced Ru +4 state as insoluble RuO 2, and hazardous volatile Cr 6+ in themore » less soluble and less volatile Cr +3 state in the glass. The melter REDOX control balances the oxidants and reductants from the feed and from processing additives such as antifoam. Currently, the Defense Waste Processing Facility (DWPF) is running a formic acid-nitric acid (FN) flowsheet where formic acid is the main reductant and nitric acid is the main oxidant. During decomposition formate and formic acid releases H 2 gas which requires close control of the melter vapor space flammability. A switch to a nitric acid-glycolic acid (GN) flowsheet is desired as the glycolic acid flowsheet releases considerably less H 2 gas upon decomposition. This would greatly simplify DWPF processing. Development of an EE term for glycolic acid in the GN flowsheet is documented in this study.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raszewski, F; Tommy Edwards, T; David Peeler, D

Sludge Batch 4 (SB4) is currently being processed in the Defense Waste Processing Facility (DWPF) using Frit 510. The slurry pumps in Tank 40 are experiencing in-leakage of bearing water, which is causing the sludge slurry in Tank 40 to become dilute at a rapid rate. Currently, the DWPF is removing this dilution water by performing caustic boiling during the Sludge Receipt and Adjustment Tank (SRAT) cycle. In order to alleviate prolonged SRAT cycle times, which may eventually impact canister production rates, the Liquid Waste Organization (LWO) performed a 100K gallon supernate decant of Tank 40 in April 2008. SRNLmore » performed a supplemental glass variability study to support the April 2008 100K gallon decant incorporating the impact of coupled operations (addition of the Actinide Removal Process (ARP) stream). Recently LWO requested that SRNL assess the impact of a second decant (up to 100K gallon) to the Frit 510-SB4 system. This second decant occurred in June 2008. LWO provided nominal compositions on May 6, 2008 representing Tank 40 prior to the second decant, following the second decant, and the SB4 Heel prior to blending with Tank 51 to constitute SB5. Paper study assessments were performed for these options based on sludge-only and coupled operations processing (ARP addition), as well as possible Na{sub 2}O additions (via NaOH additions) to both flowsheets. A review of the ComProTM database relative to the compositional region defined by the projections after the second decant coupled with Frit 510 identified only a few glasses with similar glass compositions. These glasses were acceptable from a durability perspective, but did not sufficiently cover the new glass compositional region. Therefore, SRNL recommended that a supplemental variability study be performed to support the June 2008 Tank 40 decant. Glasses were selected for the variability study based on three sludge compositional projections (sludge-only, coupled and coupled + 2 wt% Na{sub 2}O) at waste loadings (WLs) of interest to DWPF (32%, 35% and 38%). These nine glasses were fabricated and characterized using chemical composition analysis, X-ray Diffraction (XRD) and the Product Consistency Test (PCT). All of the glasses that were selected for this study satisfy the Product Composition Control System (PCCS) criteria and are deemed processable and acceptable for the DWPF, except for the SB4VS2-03 (sludge-only at 38% WL) target composition. This glass fails the T{sub L} criterion and would not be considered processable based on Slurry Mix Evaporator (SME) acceptability decisions. The durabilities of all of the study glasses (both quenched and ccc) are well below that of the normalized leachate for boron (NL [B]) of the reference EA glass (16.695 g/L) and are predictable using the current PCCS models. Very little variation exists between the NL [B] of the quenched and ccc versions of the glasses. There is some evidence of a trend toward a less durable glass as WL increases for some of the sludge projections. Frit 510 is a viable option for the processing of SB4 after a second Tank 40 decant with or without the addition of products from the ARP stream as well as the 2 wt% Na{sub 2}O addition. The addition of ARP had no negative impacts on the acceptability and predictability of the variability study glasses.« less

ANALYTICAL PLANS SUPPORTING THE SWPF GAP ANALYSIS BEING CONDUCTED WITH ENERGYSOLUTIONS AND THE VITREOUS STATE LABORATORY AT THE CUA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, T.; Peeler, D.

2014-10-28

EnergySolutions (ES) and its partner, the Vitreous State Laboratory (VSL) of The Catholic University of America (CUA), are to provide engineering and technical services support to Savannah River Remediation, LLC (SRR) for ongoing operation of the Defense Waste Processing Facility (DWPF) flowsheet as well as for modifications to improve overall plant performance. SRR has requested that the glass formulation team of Savannah River National Laboratory (SRNL) and ES-VSL develop a technical basis that validates the current Product Composition Control System models for use during the processing of the coupled flowsheet or that leads to the refinements of or modifications tomore » the models that are needed so that they may be used during the processing of the coupled flowsheet. SRNL has developed a matrix of test glasses that are to be batched and fabricated by ES-VSL as part of this effort. This document provides two analytical plans for use by ES-VSL: one plan is to guide the measurement of the chemical composition of the study glasses while the second is to guide the measurement of the durability of the study glasses based upon the results of testing by ASTM’s Product Consistency Test (PCT) Method A.« less

The Impact Of The MCU Life Extension Solvent On Sludge Batch 8 Projected Operating Windows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peeler, D. K.; Edwards, T. B.; Stone, M. E.

2013-08-14

As a part of the Actinide Removal Process (ARP)/Modular Caustic Side Solvent Extraction Unit (MCU) Life Extension Project, a next generation solvent (NGS) and a new strip acid will be deployed. The strip acid will be changed from dilute nitric acid to dilute boric acid (0.01 M). Because of these changes, experimental testing or evaluations with the next generation solvent are required to determine the impact of these changes (if any) to Chemical Process Cell (CPC) activities, glass formulation strategies, and melter operations at the Defense Waste Processing Facility (DWPF). The introduction of the dilute (0.01M) boric acid stream intomore » the DWPF flowsheet has a potential impact on glass formulation and frit development efforts since B2O3 is a major oxide in frits developed for DWPF. Prior knowledge of this stream can be accounted for during frit development efforts but that was not the case for Sludge Batch 8 (SB8). Frit 803 has already been recommended and procured for SB8 processing; altering the frit to account for the incoming boron from the strip effluent (SE) is not an option for SB8. Therefore, the operational robustness of Frit 803 to the introduction of SE including its compositional tolerances (i.e., up to 0.0125M boric acid) is of interest and was the focus of this study. The primary question to be addressed in the current study was: What is the impact (if any) on the projected operating windows for the Frit 803 – SB8 flowsheet to additions of B2O3 from the SE in the Sludge Receipt and Adjustment Tank (SRAT)? More specifically, will Frit 803 be robust to the potential compositional changes occurring in the SRAT due to sludge variation, varying additions of ARP and/or the introduction of SE by providing access to waste loadings (WLs) of interest to DWPF? The Measurement Acceptability Region (MAR) results indicate there is very little, if any, impact on the projected operating windows for the Frit 803 – SB8 system regardless of the presence or absence of ARP and SE (up to 2 wt% B2O3 contained in the SRAT and up to 2000 gallons of ARP). It should be noted that 0.95 wt% B2O3 is the nominal projected concentration in the SRAT based on a 0.0125M boric acid flowsheet with 70,000 liters of SE being added to the SRAT. The impact on CPC processing of a 0.01M boric acid solution for elution of cesium during Modular Caustic Side Solvent Extraction Unit (MCU) processing has previously been evaluated by the Savannah River National Laboratory (SRNL). Increasing the acid strength to 0.0125M boric acid to account for variations in the boric acid strength has been reviewed versus the previous evaluation. The amount of acid from the boric acid represented approximately 5% of the total acid during the previous evaluation. An increase from 0.01 to 0.0125M boric acid represents a change of approximately 1.3% which is well within the error of the acid calculation. Therefore, no significant changes to CPC processing (hydrogen generation, metal solubilities, rheological properties, REDOX control, etc.) are expected from an increase in allowable boric acid concentration from 0.01M to 0.0125M.« less

SCIX IMPACT ON DWPF CPC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koopman, D.

2011-07-14

A program was conducted to systematically evaluate potential impacts of the proposed Small Column Ion Exchange (SCIX) process on the Defense Waste Processing Facility (DWPF) Chemical Processing Cell (CPC). The program involved a series of interrelated tasks. Past studies of the impact of crystalline silicotitanate (CST) and monosodium titanate (MST) on DWPF were reviewed. Paper studies and material balance calculations were used to establish reasonable bounding levels of CST and MST in sludge. Following the paper studies, Sludge Batch 10 (SB10) simulant was modified to have both bounding and intermediate levels of MST and ground CST. The SCIX flow sheetmore » includes grinding of the CST which is larger than DWPF frit when not ground. Nominal ground CST was not yet available, therefore a similar CST ground previously in Savannah River National Laboratory (SRNL) was used. It was believed that this CST was over ground and that it would bound the impact of nominal CST on sludge slurry properties. Lab-scale simulations of the DWPF CPC were conducted using SB10 simulants with no, intermediate, and bounding levels of CST and MST. Tests included both the Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) cycles. Simulations were performed at high and low acid stoichiometry. A demonstration of the extended CPC flowsheet was made that included streams from the site interim salt processing operations. A simulation using irradiated CST and MST was also completed. An extensive set of rheological measurements was made to search for potential adverse consequences of CST and MST and slurry rheology in the CPC. The SCIX CPC impact program was conducted in parallel with a program to evaluate the impact of SCIX on the final DWPF glass waste form and on the DWPF melter throughput. The studies must be considered together when evaluating the full impact of SCIX on DWPF. Due to the fact that the alternant flowsheet for DWPF has not been selected, this study did not consider the impact of proposed future alternative DWPF CPC flowsheets. The impact of the SCIX streams on DWPF processing using the selected flowsheet need to be considered as part of the technical baseline studies for coupled processing with the selected flowsheet. In addition, the downstream impact of aluminum dissolution on waste containing CST and MST has not yet been evaluated. The current baseline would not subject CST to the aluminum dissolution process and technical concerns with performing the dissolution with CST have been expressed. Should this option become feasible, the downstream impact should be considered. The main area of concern for DWPF from aluminum dissolution is an impact on rheology. The SCIX project is planning for SRNL to complete MST, CST, and sludge rheology testing to evaluate any expected changes. The impact of ground CST transport and flush water on the DWPF CPC feed tank (and potential need for decanting) has not been defined or studied.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fox, K. M.

The U.S. Department of Energy (DOE), Office of Environmental Management (EM) is sponsoring an international, collaborative project to develop a fundamental model for sulfate solubility in nuclear waste glass. The solubility of sulfate has a significant impact on the achievable waste loading for nuclear waste forms within the DOE complex. These wastes can contain relatively high concentrations of sulfate, which has low solubility in borosilicate glass. This is a significant issue for low-activity waste (LAW) glass and is projected to have a major impact on the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Sulfate solubility has also been amore » limiting factor for recent high level waste (HLW) sludge processed at the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF). The low solubility of sulfate in glass, along with melter and off-gas corrosion constraints, dictate that the waste be blended with lower sulfate concentration waste sources or washed to remove sulfate prior to vitrification. The development of enhanced borosilicate glass compositions with improved sulfate solubility will allow for higher waste loadings and accelerate mission completion.The objective of the current scope being pursued by SHU is to mature the sulfate solubility model to the point where it can be used to guide glass composition development for DWPF and WTP, allowing for enhanced waste loadings and waste throughput at these facilities. A series of targeted glass compositions was selected to resolve data gaps in the model and is identified as Stage III. SHU fabricated these glasses and sent samples to SRNL for chemical composition analysis. SHU will use the resulting data to enhance the sulfate solubility model and resolve any deficiencies. In this report, SRNL provides chemical analyses for the Stage III, simulated HLW glasses fabricated by SHU in support of the sulfate solubility model development.« less

IMPACTS OF ANTIFOAM ADDITIONS AND ARGON BUBBLING ON DEFENSE WASTE PROCESSING FACILITY REDUCTION/OXIDATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C.; Johnson, F.

2012-06-05

During melting of HLW glass, the REDOX of the melt pool cannot be measured. Therefore, the Fe{sup +2}/{Sigma}Fe ratio in the glass poured from the melter must be related to melter feed organic and oxidant concentrations to ensure production of a high quality glass without impacting production rate (e.g., foaming) or melter life (e.g., metal formation and accumulation). A production facility such as the Defense Waste Processing Facility (DWPF) cannot wait until the melt or waste glass has been made to assess its acceptability, since by then no further changes to the glass composition and acceptability are possible. therefore, themore » acceptability decision is made on the upstream process, rather than on the downstream melt or glass product. That is, it is based on 'feed foward' statistical process control (SPC) rather than statistical quality control (SQC). In SPC, the feed composition to the melter is controlled prior to vitrification. Use of the DWPF REDOX model has controlled the balanjce of feed reductants and oxidants in the Sludge Receipt and Adjustment Tank (SRAT). Once the alkali/alkaline earth salts (both reduced and oxidized) are formed during reflux in the SRAT, the REDOX can only change if (1) additional reductants or oxidants are added to the SRAT, the Slurry Mix Evaporator (SME), or the Melter Feed Tank (MFT) or (2) if the melt pool is bubble dwith an oxidizing gas or sparging gas that imposes a different REDOX target than the chemical balance set during reflux in the SRAT.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, M. S.; Miller, D. H.; Fowley, M. D.

The Savannah River National Laboratory (SRNL) was tasked to support validation of the Defense Waste Processing Facility (DWPF) melter offgas flammability model for the nitric-glycolic (NG) flowsheet. The work supports Deliverable 4 of the DWPF & Saltstone Facility Engineering Technical Task Request (TTR)1 and is supplemental to the Cold Cap Evaluation Furnace (CEF) testing conducted in 2014.2 The Slurry-fed Melt Rate Furnace (SMRF) was selected for the supplemental testing as it requires significantly less resources than the CEF and could provide a tool for more rapid analysis of melter feeds in the future. The SMRF platform has been used previouslymore » to evaluate melt rate behavior of DWPF glasses, but was modified to accommodate analysis of the offgas stream. Additionally, the Melt Rate Furnace (MRF) and Quartz Melt Rate Furnace (QMRF) were utilized for evaluations. MRF data was used exclusively for melt behavior observations and REDuction/OXidation (REDOX) prediction comparisons and will be briefly discussed in conjunction with its support of the SMRF testing. The QMRF was operated similarly to the SMRF for the same TTR task, but will be discussed in a separate future report. The overall objectives of the SMRF testing were to; 1) Evaluate the efficacy of the SMRF as a platform for steady state melter testing with continuous feeding and offgas analysis; and 2) Generate supplemental melter offgas flammability data to support the melter offgas flammability modelling effort for DWPF implementation of the NG flowsheet.« less

DWPF Simulant CPC Studies For SB8

DOE Office of Scientific and Technical Information (OSTI.GOV)

Newell, J. D.

2013-09-25

Prior to processing a Sludge Batch (SB) in the Defense Waste Processing Facility (DWPF), flowsheet studies using simulants are performed. Typically, the flowsheet studies are conducted based on projected composition(s). The results from the flowsheet testing are used to 1) guide decisions during sludge batch preparation, 2) serve as a preliminary evaluation of potential processing issues, and 3) provide a basis to support the Shielded Cells qualification runs performed at the Savannah River National Laboratory (SRNL). SB8 was initially projected to be a combination of the Tank 40 heel (Sludge Batch 7b), Tank 13, Tank 12, and the Tank 51more » heel. In order to accelerate preparation of SB8, the decision was made to delay the oxalate-rich material from Tank 12 to a future sludge batch. SB8 simulant studies without Tank 12 were reported in a separate report.1 The data presented in this report will be useful when processing future sludge batches containing Tank 12. The wash endpoint target for SB8 was set at a significantly higher sodium concentration to allow acceptable glass compositions at the targeted waste loading. Four non-coupled tests were conducted using simulant representing Tank 40 at 110-146% of the Koopman Minimum Acid requirement. Hydrogen was generated during high acid stoichiometry (146% acid) SRAT testing up to 31% of the DWPF hydrogen limit. SME hydrogen generation reached 48% of of the DWPF limit for the high acid run. Two non-coupled tests were conducted using simulant representing Tank 51 at 110-146% of the Koopman Minimum Acid requirement. Hydrogen was generated during high acid stoichiometry SRAT testing up to 16% of the DWPF limit. SME hydrogen generation reached 49% of the DWPF limit for hydrogen in the SME for the high acid run. Simulant processing was successful using previously established antifoam addition strategy. Foaming during formic acid addition was not observed in any of the runs. Nitrite was destroyed in all runs and no N2O was detected during SME processing. Mercury behavior was consistent with that seen in previous SRAT runs. Mercury was stripped below the DWPF limit on 0.8 wt% for all runs. Rheology yield stress fell within or below the design basis of 1-5 Pa. The low acid Tank 40 run (106% acid stoichiometry) had the highest yield stress at 3.78 Pa.« less

Inhibiting localized corrosion during storage of dilute SRP wastes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oblath, S.B.; Congdon, J.W.

1986-01-01

High-level radioactive waste will be incorporated in borosilicate glass in the Defense Waste Processing Facility (DWPF) at the Savannah River Plant (SRP). As part of this process, large volumes of inorganic salt wastes will be decontaminated for disposal as low-level waste. The principal contaminants, /sup 137/Cs and /sup 90/Sr, are removed by treatment with sodium tetraphenylborate and sodium titanate. The resulting solids will be slurried with a dilute salt solution and stored in existing carbon steel tanks for several years prior to processing and disposal. Initial tests indicated a tendency for localized corrosion of the tanks. An investigation, using nonradioactivemore » simulants for the expected solution compositions, identified inhibitors which would protect the steel. Changes in solution compositions over time, due to radiolytic effects, were also accounted for by the simulants. Six inhibitors were identified which would protect the steel tanks. The effects these inhibitors would have on later processing steps in the DWPF were then evaluated. After this process, only sodium nitrite remained as an inhibitor that was both effective and compatible with the DWPF. The use of this inhibitor has been demonstrated on a real waste slurry.« less

Evaluation of quartz melt rate furnace with the nitric-glycolic flowsheet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, M. S.; Miller, D. H.

The Savannah River National Laboratory (SRNL) was tasked to support validation of the Defense Waste Processing Facility (DWPF) melter offgas flammability model for the Nitric-Glycolic (NG) flowsheet. The work is supplemental to the Cold Cap Evaluation Furnace (CEF) testing conducted in 20141 and the Slurry-fed Melt Rate Furnace (SMRF) testing conducted in 20162 that supported Deliverable 4 of the DWPF & Saltstone Facility Engineering Technical Task Request (TTR).3 The Quartz Melt Rate Furnace (QMRF) was evaluated as a bench-scale scoping tool to potentially be used in lieu of or simply prior to the use of the larger-scale SMRF or CEF.more » The QMRF platform has been used previously to evaluate melt rate behavior and offgas compositions of DWPF glasses prepared from the Nitric-Formic (NF) flowsheet but not for the NG flowsheet and not with continuous feeding.4 The overall objective of the 2016-2017 testing was to evaluate the efficacy of the QMRF as a lab-scale platform for steady state, continuously fed melter testing with the NG flowsheet as an alternative to more expensive and complex testing with the SMRF or CEF platforms.« less

DWPF simulant CPC studies for SB8

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koopman, D. C.; Zamecnik, J. R.

2013-06-25

The Savannah River National Laboratory (SRNL) accepted a technical task request (TTR) from Waste Solidification Engineering to perform simulant tests to support the qualification of Sludge Batch 8 (SB8) and to develop the flowsheet for SB8 in the Defense Waste Processing Facility (DWPF). These efforts pertained to the DWPF Chemical Process Cell (CPC). Separate studies were conducted for frit development and glass properties (including REDOX). The SRNL CPC effort had two primary phases divided by the decision to drop Tank 12 from the SB8 constituents. This report focuses on the second phase with SB8 compositions that do not contain themore » Tank 12 piece. A separate report will document the initial phase of SB8 testing that included Tank 12. The second phase of SB8 studies consisted of two sets of CPC studies. The first study involved CPC testing of an SB8 simulant for Tank 51 to support the CPC demonstration of the washed Tank 51 qualification sample in the SRNL Shielded Cells facility. SB8-Tank 51 was a high iron-low aluminum waste with fairly high mercury and moderate noble metal concentrations. Tank 51 was ultimately washed to about 1.5 M sodium which is the highest wash endpoint since SB3-Tank 51. This study included three simulations of the DWPF Sludge Receipt and Adjustment Tank (SRAT) cycle and Slurry Mix Evaporator (SME) cycle with the sludge-only flowsheet at nominal DWPF processing conditions and three different acid stoichiometries. These runs produced a set of recommendations that were used to guide the successful SRNL qualification SRAT/SME demonstration with actual Tank 51 washed waste. The second study involved five SRAT/SME runs with SB8-Tank 40 simulant. Four of the runs were designed to define the acid requirements for sludge-only processing in DWPF with respect to nitrite destruction and hydrogen generation. The fifth run was an intermediate acid stoichiometry demonstration of the coupled flowsheet for SB8. These runs produced a set of processing recommendations for DWPF along with some data related to Safety Class documentation at DWPF. Some significant observations regarding SB8 follow: Reduced washing in Tank 51 led to an increase in the wt.% soluble solids of the DWPF feed. If wt.% total solids for the SRAT and SME product weren’t adjusted upward to maintain insoluble solids levels similar to past sludge batches, then the rheological properties of the slurry went below the low end of the DWPF design bases for the SRAT and SME. Much higher levels of dissolved manganese were found in the SRAT and SME products than in recent sludge batches. Closed crucible melts were more reduced than expected. The working hypothesis is that the soluble Mn is less oxidizing than assumed in the REDOX calculations. A change in the coefficient for Mn in the REDOX equation was recommended in a separate report. The DWPF (Hsu) stoichiometric acid equation was examined in detail to better evaluate how to control acid in DWPF. The existing DWPF equation can likely be improved without changing the required sample analyses through a paper study using existing data. The recommended acid stoichiometry for initial SB8 SRAT batches is 115-120% stoichiometry until some processing experience is gained. The conservative range (based on feed properties) of stoichiometric factors derived in this study was from 110-147%, but SRNL recommends using only the lower half of this range, 110-126% even after initial batches provide processing experience. The stoichiometric range for sludge-only processing appears to be suitable for coupled operation based on results from the run in the middle of the range. Catalytic hydrogen was detectable (>0.005 vol%) in all SRAT and SME cycles. Hydrogen reached 30-35% of the SRAT and SME limits at the mid-point of the stoichiometry window (bounding noble metals and acid demand).« less

SLUDGE WASHING AND DEMONSTRATION OF THE DWPF FLOWSHEET IN THE SRNL SHIELDED CELLS FOR SLUDGE BATCH 7A QUALIFICATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pareizs, J.; Billings, A.; Click, D.

2011-07-08

Waste Solidification Engineering (WSE) has requested that characterization and a radioactive demonstration of the next batch of sludge slurry (Sludge Batch 7a*) be completed in the Shielded Cells Facility of the Savannah River National Laboratory (SRNL) via a Technical Task Request (TTR). This characterization and demonstration, or sludge batch qualification process, is required prior to transfer of the sludge from Tank 51 to the Defense Waste Processing Facility (DWPF) feed tank (Tank 40). The current WSE practice is to prepare sludge batches in Tank 51 by transferring sludge from other tanks. Discharges of nuclear materials from H Canyon are oftenmore » added to Tank 51 during sludge batch preparation. The sludge is washed and transferred to Tank 40, the current DWPF feed tank. Prior to transfer of Tank 51 to Tank 40, SRNL simulates the Tank Farm and DWPF processes with a Tank 51 sample (referred to as the qualification sample). Sludge Batch 7a (SB7a) is composed of portions of Tanks 4, 7, and 12; the Sludge Batch 6 heel in Tank 51; and a plutonium stream from H Canyon. SRNL received the Tank 51 qualification sample (sample ID HTF-51-10-125) following sludge additions to Tank 51. This report documents: (1) The washing (addition of water to dilute the sludge supernate) and concentration (decanting of supernate) of the SB7a - Tank 51 qualification sample to adjust sodium content and weight percent insoluble solids to Tank Farm projections. (2) The performance of a DWPF Chemical Process Cell (CPC) simulation using the washed Tank 51 sample. The simulation included a Sludge Receipt and Adjustment Tank (SRAT) cycle, where acid was added to the sludge to destroy nitrite and reduce mercury, and a Slurry Mix Evaporator (SME) cycle, where glass frit was added to the sludge in preparation for vitrification. The SME cycle also included replication of five canister decontamination additions and concentrations. Processing parameters were based on work with a non-radioactive simulant. (3) Vitrification of a portion of the SME product and characterization and durability testing (as measured by the Product Consistency Test (PCT)) of the resulting glass. (4) Rheology measurements of the initial slurry samples and samples after each phase of CPC processing. This program was controlled by a Task Technical and Quality Assurance Plan (TTQAP), and analyses were guided by an Analytical Study Plan. This work is Technical Baseline Research and Development (R&D) for the DWPF. It should be noted that much of the data in this document has been published in interoffice memoranda. The intent of this technical report is bring all of the SB7a related data together in a single permanent record and to discuss the overall aspects of SB7a processing.« less

Description of Defense Waste Processing Facility reference waste form and canister. Revision 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baxter, R.G.

1983-08-01

The Defense Waste Processing Facility (DWPF) will be located at the Savannah River Plant in Aiken, SC, and is scheduled for construction authorization during FY-1984. The reference waste form is borosilicate glass containing approx. 28 wt % sludge oxides, with the balance glass frit. Borosilicate glass was chosen because of its high resistance to leaching by water, its relatively high solubility for nuclides found in the sludge, and its reasonably low melting temperature. The glass frit contains about 58% SiO/sub 2/ and 15% B/sub 2/O/sub 3/. Leachabilities of SRP waste glasses are expected to approach 10/sup -8/ g/m/sup 2/-day basedmore » upon 1000-day tests using glasses containing SRP radioactive waste. Tests were performed under a wide variety of conditions simulating repository environments. The canister is filled with 3260 lb of glass which occupies about 85% of the free canister volume. The filled canister will generate approx. 470 watts when filled with oxides from 5-year-old sludge and 15-year-old supernate from the sludge and supernate processes. The radionuclide content of the canister is about 177,000 ci, with a radiation level of 5500 rem/h at canister surface contact. The reference canister is fabricated of standard 24-in.-OD, Schedule 20, 304L stainless steel pipe with a dished bottom, domed head, and a combined lifting and welding flange on the head neck. The overall canister length is 9 ft 10 in. with a 3/8-in. wall thickness. The 3-m canister length was selected to reduce equipment cell height in the DWPF to a practical size. The canister diameter was selected as an optimum size from glass quality considerations, a logical size for repository handling and to ensure that a filled canister with its double containment shipping cask could be accommodated on a legal-weight truck. The overall dimensions and weight appear to be compatible with preliminary assessments of repository requirements. 10 references.« less

Solidification of Savannah River plant high level waste

NASA Astrophysics Data System (ADS)

Maher, R.; Shafranek, L. F.; Kelley, J. A.; Zeyfang, R. W.

1981-11-01

Authorization for construction of the Defense Waste Processing Facility (DWPF) is expected in FY-83. The optimum time for stage 2 authorization is about three years later. Detailed design and construction will require approximately five years for stage 1, with stage 2 construction completed about two to three years later. Production of canisters of waste glass would begin in 1988, and the existing backlog of high level waste sludge stored at SRP would be worked off by about the year 2000. Stage 2 operation could begin in 1990. The technology and engineering are ready for construction and eventual operation of the DWPF for immobilizing high level radioactive waste at Savannah River Plant (SRP). Proceeding with this project will provide the public, and the leadership of this country, with a crucial demonstration that a major quanitity of existing high level nuclear wastes can be safely and permanently immobilized.

DWPF Melt Cell Crawler

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ward, C.R.

2003-04-08

On December 2, 2002, Remote and Specialty Equipment Systems (RSES) of the Savannah River Technology Center (SRTC) was requested to build a remotely operated crawler to assist in cleaning the Defense Waste Processing Facility (DWPF) melt cell floor of glass, tools, and other debris. The crawler was to assist a grapple and vacuum system in cleaning the cell. The crawler was designed to push glass and debris into piles so that the grapple could pick up the material and place it in waste bins. The crawler was also designed to maneuver the end of the vacuum hose, if needed. Inmore » addition, the crawler was designed to clean the area beneath the cell worktable that was inaccessible to the grapple and vacuum system. Originally, the system was to be ready for deployment by December 17. The date was moved up to December 12 to better utilize the available time for clean up. The crawler was designed and built in 10 days and completed cleaning the melt cell in 8 days. Due to initial problems with the grapple and vacuum system, the crawler completed essentially all of the cleanup tasks by itself. The crawler also cleaned an area on the west side of the cell that was not initially slated for cleaning.« less

SLUDGE BATCH 7B QUALIFICATION ACTIVITIES WITH SRS TANK FARM SLUDGE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pareizs, J.; Click, D.; Lambert, D.

2011-11-16

Waste Solidification Engineering (WSE) has requested that characterization and a radioactive demonstration of the next batch of sludge slurry - Sludge Batch 7b (SB7b) - be completed in the Shielded Cells Facility of the Savannah River National Laboratory (SRNL) via a Technical Task Request (TTR). This characterization and demonstration, or sludge batch qualification process, is required prior to transfer of the sludge from Tank 51 to the Defense Waste Processing Facility (DWPF) feed tank (Tank 40). The current WSE practice is to prepare sludge batches in Tank 51 by transferring sludge from other tanks. Discharges of nuclear materials from Hmore » Canyon are often added to Tank 51 during sludge batch preparation. The sludge is washed and transferred to Tank 40, the current DWPF feed tank. Prior to transfer of Tank 51 to Tank 40, SRNL typically simulates the Tank Farm and DWPF processes with a Tank 51 sample (referred to as the qualification sample). With the tight schedule constraints for SB7b and the potential need for caustic addition to allow for an acceptable glass processing window, the qualification for SB7b was approached differently than past batches. For SB7b, SRNL prepared a Tank 51 and a Tank 40 sample for qualification. SRNL did not receive the qualification sample from Tank 51 nor did it simulate all of the Tank Farm washing and decanting operations. Instead, SRNL prepared a Tank 51 SB7b sample from samples of Tank 7 and Tank 51, along with a wash solution to adjust the supernatant composition to the final SB7b Tank 51 Tank Farm projections. SRNL then prepared a sample to represent SB7b in Tank 40 by combining portions of the SRNL-prepared Tank 51 SB7b sample and a Tank 40 Sludge Batch 7a (SB7a) sample. The blended sample was 71% Tank 40 (SB7a) and 29% Tank 7/Tank 51 on an insoluble solids basis. This sample is referred to as the SB7b Qualification Sample. The blend represented the highest projected Tank 40 heel (as of May 25, 2011), and thus, the highest projected noble metals content for SB7b. Characterization was performed on the Tank 51 SB7b samples and SRNL performed DWPF simulations using the Tank 40 SB7b material. This report documents: (1) The preparation and characterization of the Tank 51 SB7b and Tank 40 SB7b samples. (2) The performance of a DWPF Chemical Process Cell (CPC) simulation using the SB7b Tank 40 sample. The simulation included a Sludge Receipt and Adjustment Tank (SRAT) cycle, where acid was added to the sludge to destroy nitrite and reduce mercury, and a Slurry Mix Evaporator (SME) cycle, where glass frit was added to the sludge in preparation for vitrification. The SME cycle also included replication of five canister decontamination additions and concentrations. Processing parameters were based on work with a nonradioactive simulant. (3) Vitrification of a portion of the SME product and characterization and durability testing (as measured by the Product Consistency Test (PCT)) of the resulting glass. (4) Rheology measurements of the SRAT receipt, SRAT product, and SME product. This program was controlled by a Task Technical and Quality Assurance Plan (TTQAP), and analyses were guided by an Analytical Study Plan. This work is Technical Baseline Research and Development (R&D) for the DWPF. It should be noted that much of the data in this document has been published in interoffice memoranda. The intent of this technical report is bring all of the SB7b related data together in a single permanent record and to discuss the overall aspects of SB7b processing.« less

Yield Stress Reduction of DWPF Melter Feed Slurries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, M.E.; Smith, M.E.

2007-07-01

The Defense Waste Processing Facility (DWPF) at the Savannah River Site vitrifies High Level Waste for repository internment. The process consists of three major steps: waste pretreatment, vitrification, and canister decontamination/sealing. The HLW consists of insoluble metal hydroxides and soluble sodium salts. The pretreatment process acidifies the sludge with nitric and formic acids, adds the glass formers as glass frit, then concentrates the resulting slurry to approximately 50 weight percent (wt%) total solids. This slurry is fed to the joule-heated melter where the remaining water is evaporated followed by calcination of the solids and conversion to glass. The Savannah Rivermore » National Laboratory (SRNL) is currently assisting DWPF efforts to increase throughput of the melter. As part of this effort, SRNL has investigated methods to increase the solids content of the melter feed to reduce the heat load required to complete the evaporation of water and allow more of the energy available to calcine and vitrify the waste. The process equipment in the facility is fixed and cannot process materials with high yield stresses, therefore increasing the solids content will require that the yield stress of the melter feed slurries be reduced. Changing the glass former added during pretreatment from an irregularly shaped glass frit to nearly spherical beads was evaluated. The evaluation required a systems approach which included evaluations of the effectiveness of beads in reducing the melter feed yield stress as well as evaluations of the processing impacts of changing the frit morphology. Processing impacts of beads include changing the settling rate of the glass former (which effects mixing and sampling of the melter feed slurry and the frit addition equipment) as well as impacts on the melt behavior due to decreased surface area of the beads versus frit. Beads were produced from the DWPF process frit by fire polishing. The frit was allowed to free fall through a flame, then quenched with a water spray. Approximately 90% of the frit was converted to beads by this process. Yield stress reduction was measured by preparing melter feed slurries (using nonradioactive HLW simulants) that contain beads and comparing the yield stress with melter feed containing frit. A second set of tests was performed with beads of various diameters to determine if a decrease in diameter affected the results. Smaller particle size was shown to increase yield stress when frit is utilized. The settling rate of the beads was required to match the settling rate of the frit, therefore a decrease in particle size was anticipated. Settling tests were conducted in water, xanthan gum solutions, and in non-radioactive simulants of the HLW. The tests used time-lapse video-graphy as well as solids sampling to evaluate the settling characteristics of beads compared to frit of the same particle size. A preliminary melt rate evaluation was performed using a dry-fed Melt Rate Furnace (MRF) developed by SRNL. Preliminary evaluation of the impact of beading the frit on the frit addition system were completed by conducting flow loop testing. A recirculation loop was built with a total length of about 30 feet. Pump power, flow rate, outlet pressure, and observations of the flow in the horizontal upper section of the loop were noted. The recirculation flow was then gradually reduced and the above items recorded until settling was noted in the recirculation line. Overall, the data shows that the line pressure increased as the solids were increased for the same flow rate. In addition, the line pressure was higher for Frit 320 than the beads at the same solids level and flow. With the observations, a determination of minimum velocity to prevent settling could be done, but a graph of the line pressures versus velocity for the various tests was deemed to more objective. The graph shows that the inflection point in pressure drop is about the same for the beads and Frit 320. This indicates that the bead slurry would not require higher flows rates than frit slurry at DWPF during transfers. Another key finding was that the pump impeller was not significantly damaged by the bead slurry, while the Frit 320 slurry rapidly destroyed the impeller. Evidence of this was first observed when black particles were seen in the Frit 320 slurry being recirculated and then confirmed by a post-test inspection of the impeller. Finally, the pumping of bead slurry could be recovered even if flow is stopped. The Frit 320 slurry could not be restarted after stopping flow due to the nature of the frit to pack tightly when settled. Beads were shown to represent a significant process improvement versus frit for the DWPF process in lowering yield stress of the melter feed. Lower erosion of process equipment is another expected benefit.« less

Using polymerization, glass structure, and quasicrystalline theory to produce high level radioactive borosilicate glass remotely: a 20+ year legacy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, Carol M.

Vitrification is currently the most widely used technology for the treatment of high level radioactive wastes (HLW) throughout the world. Most of the nations that have generated HLW are immobilizing in borosilicate glass. One of the primary reasons that glass has become the most widely used immobilization media is the relative simplicity of the vitrification process, e.g. melt a highly variable waste with some glass forming additives such as SiO 2 and B 2O 3 in the form of a premelted frit and pour the molten mixture into a stainless steel canister. Seal the canister before moisture can enter themore » canister (10’ tall by 2’ in diameter) so the canister does not corrode from the inside out. Glass has also become widely used for HLW is that due to the fact that the short range order (SRO) and medium range order (MRO) found in the structure of glass atomistically bonds the radionuclides and hazardous species in the waste. The SRO and MRO have also been found to govern the melt properties such as viscosity and resistivity of the melt and the crystallization potential and solubility of certain species. Furthermore, the molecular structure of the glass also controls the glass durability, i.e. the contaminant/radionuclide release, by establishing the distribution of ion exchange sites, hydrolysis sites, and the access of water to those sites. The molecular structure is flexible and hence accounts for the flexibility of glass formulations to HLW waste variability. Nuclear waste glasses melt between 1050-1150°C which minimizes the volatility of radioactive components such as 99Tc, 137Cs, and 129I. Nuclear waste glasses have good long term stability including irradiation resistance. Process control models were developed based on the molecular structure of glass, polymerization theory of glass, and quasicrystalline theory of glass crystallization. These models create a glass which is durable, pourable, and processable with 95% accuracy without knowing from batch to batch what the composition of the waste coming out of the storage tanks will be. These models have operated the Savannah River Site Defense Waste Processing Facility (SRS DWPF), which is the world’s largest HLW Joule heated ceramic melter, since 1996. This unique “feed forward” process control, which qualifies the durability, pourability, and processability of the waste plus glass additive mixture before it enters the melter, has enabled ~8000 tons of HLW glass and 4242 canisters to be produced since 1996 with only one melter replacement.« less

Using polymerization, glass structure, and quasicrystalline theory to produce high level radioactive borosilicate glass remotely: a 20+ year legacy

DOE PAGES

Jantzen, Carol M.

2017-03-27

Vitrification is currently the most widely used technology for the treatment of high level radioactive wastes (HLW) throughout the world. Most of the nations that have generated HLW are immobilizing in borosilicate glass. One of the primary reasons that glass has become the most widely used immobilization media is the relative simplicity of the vitrification process, e.g. melt a highly variable waste with some glass forming additives such as SiO 2 and B 2O 3 in the form of a premelted frit and pour the molten mixture into a stainless steel canister. Seal the canister before moisture can enter themore » canister (10’ tall by 2’ in diameter) so the canister does not corrode from the inside out. Glass has also become widely used for HLW is that due to the fact that the short range order (SRO) and medium range order (MRO) found in the structure of glass atomistically bonds the radionuclides and hazardous species in the waste. The SRO and MRO have also been found to govern the melt properties such as viscosity and resistivity of the melt and the crystallization potential and solubility of certain species. Furthermore, the molecular structure of the glass also controls the glass durability, i.e. the contaminant/radionuclide release, by establishing the distribution of ion exchange sites, hydrolysis sites, and the access of water to those sites. The molecular structure is flexible and hence accounts for the flexibility of glass formulations to HLW waste variability. Nuclear waste glasses melt between 1050-1150°C which minimizes the volatility of radioactive components such as 99Tc, 137Cs, and 129I. Nuclear waste glasses have good long term stability including irradiation resistance. Process control models were developed based on the molecular structure of glass, polymerization theory of glass, and quasicrystalline theory of glass crystallization. These models create a glass which is durable, pourable, and processable with 95% accuracy without knowing from batch to batch what the composition of the waste coming out of the storage tanks will be. These models have operated the Savannah River Site Defense Waste Processing Facility (SRS DWPF), which is the world’s largest HLW Joule heated ceramic melter, since 1996. This unique “feed forward” process control, which qualifies the durability, pourability, and processability of the waste plus glass additive mixture before it enters the melter, has enabled ~8000 tons of HLW glass and 4242 canisters to be produced since 1996 with only one melter replacement.« less

EVALUATION OF ARG-1 SAMPLES PREPARED BY CESIUM CARBONATE DISSOLUTION DURING THE ISOLOK SME ACCEPTABILITY TESTING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, T.; Hera, K.; Coleman, C.

2011-12-05

Evaluation of Defense Waste Processing Facility (DWPF) Chemical Process Cell (CPC) cycle time identified several opportunities to improve the CPC processing time. The Mechanical Systems & Custom Equipment Development (MS&CED) Section of the Savannah River National Laboratory (SRNL) recently completed the evaluation of one of these opportunities - the possibility of using an Isolok sampling valve as an alternative to the Hydragard valve for taking DWPF process samples at the Slurry Mix Evaporator (SME). The use of an Isolok for SME sampling has the potential to improve operability, reduce maintenance time, and decrease CPC cycle time. The SME acceptability testingmore » for the Isolok was requested in Task Technical Request (TTR) HLW-DWPF-TTR-2010-0036 and was conducted as outlined in Task Technical and Quality Assurance Plan (TTQAP) SRNLRP-2011-00145. RW-0333P QA requirements applied to the task, and the results from the investigation were documented in SRNL-STI-2011-00693. Measurement of the chemical composition of study samples was a critical component of the SME acceptability testing of the Isolok. A sampling and analytical plan supported the investigation with the analytical plan directing that the study samples be prepared by a cesium carbonate (Cs{sub 2}CO{sub 3}) fusion dissolution method and analyzed by Inductively Coupled Plasma - Optical Emission Spectroscopy (ICP-OES). The use of the cesium carbonate preparation method for the Isolok testing provided an opportunity for an additional assessment of this dissolution method, which is being investigated as a potential replacement for the two methods (i.e., sodium peroxide fusion and mixed acid dissolution) that have been used at the DWPF for the analysis of SME samples. Earlier testing of the Cs{sub 2}CO{sub 3} method yielded promising results which led to a TTR from Savannah River Remediation, LLC (SRR) to SRNL for additional support and an associated TTQAP to direct the SRNL efforts. A technical report resulting from this work was issued that recommended that the mixed acid method be replaced by the Cs{sub 2}CO{sub 3} method for the measurement of magnesium (Mg), sodium (Na), and zirconium (Zr) with additional testing of the method by DWPF Laboratory being needed before further implementation of the Cs{sub 2}CO{sub 3} method at that laboratory. While the SME acceptability testing of the Isolok does not address any of the open issues remaining after the publication of the recommendation for the replacement of the mixed acid method by the Cs{sub 2}CO{sub 3} method (since those issues are to be addressed by the DWPF Laboratory), the Cs{sub 2}CO{sub 3} testing associated with the Isolok testing does provide additional insight into the performance of the method as conducted by SRNL. The performance is to be investigated by looking to the composition measurement data generated by the samples of a standard glass, the Analytical Reference Glass - 1 (ARG-1), that were prepared by the Cs{sub 2}CO{sub 3} method and included in the SME acceptability testing of the Isolok. The measurements of these samples were presented as part of the study results, but no statistical analysis of these measurements was conducted as part of those results. It is the purpose of this report to provide that analysis, which was supported using JMP Version 7.0.2.« less

PRELIMINARY EVALUATION OF DWPF IMPACTS OF BORIC ACID USE IN CESIUM STRIP FOR SWPF AND MCU

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, M.

2010-09-28

A new solvent system is being evaluated for use in the Modular Caustic-Side Solvent Extraction Unit (MCU) and in the Salt Waste Processing Facility (SWPF). The new system includes the option to replace the current dilute nitric acid strip solution with boric acid. To support this effort, the impact of using 0.01M, 0.1M, 0.25M and 0.5M boric acid in place of 0.001M nitric acid was evaluated for impacts on the DWPF facility. The evaluation only covered the impacts of boric acid in the strip effluent and does not address the other changes in solvents (i.e., the new extractant, called MaxCalix,more » or the new suppressor, guanidine). Boric acid additions may lead to increased hydrogen generation during the SRAT and SME cycles as well as change the rheological properties of the feed. The boron in the strip effluent will impact glass composition and could require each SME batch to be trimmed with boric acid to account for any changes in the boron from strip effluent additions. Addition of boron with the strip effluent will require changes in the frit composition and could lead to changes in melt behavior. The severity of the impacts from the boric acid additions is dependent on the amount of boric acid added by the strip effluent. The use of 0.1M or higher concentrations of boric acid in the strip effluent was found to significantly impact DWPF operations while the impact of 0.01M boric acid is expected to be relatively minor. Experimental testing is required to resolve the issues identified during the preliminary evaluation. The issues to be addressed by the testing are: (1) Impact on SRAT acid addition and hydrogen generation; (2) Impact on melter feed rheology; (3) Impact on glass composition control; (4) Impact on frit production; and (5) Impact on melter offgas. A new solvent system is being evaluated for use in the Modular Caustic-Side Solvent Extraction Unit (MCU) and in the Salt Waste Processing Facility (SWPF). The new system includes the option to replace the current dilute nitric acid strip solution with boric acid. To support this effort, the impact of using 0.01M, 0.1M, 0.25M and 0.5M boric acid in place of 0.001M nitric acid was evaluated for impacts on the DWPF facility. The evaluation only covered the impacts of boric acid in the strip effluent and does not address the other changes in solvents (i.e., the new extractant, called MaxCalix, or the new suppressor, guanidine). Experimental testing with the improved solvent is required to determine the impact of any changes in the entrained solvent on DWPF processing.« less

DWPF RECYCLE EVAPORATOR FLOWSHEET EVALUATION (U)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, M

2005-04-30

The Defense Waste Processing Facility (DWPF) converts the high level waste slurries stored at the Savannah River Site into borosilicate glass for long-term storage. The vitrification process results in the generation of approximately five gallons of dilute recycle streams for each gallon of waste slurry vitrified. This dilute recycle stream is currently transferred to the H-area Tank Farm and amounts to approximately 1,400,000 gallons of effluent per year. Process changes to incorporate salt waste could increase the amount of effluent to approximately 2,900,000 gallons per year. The recycle consists of two major streams and four smaller streams. The first majormore » recycle stream is condensate from the Chemical Process Cell (CPC), and is collected in the Slurry Mix Evaporator Condensate Tank (SMECT). The second major recycle stream is the melter offgas which is collected in the Off Gas Condensate Tank (OGCT). The four smaller streams are the sample flushes, sump flushes, decon solution, and High Efficiency Mist Eliminator (HEME) dissolution solution. These streams are collected in the Decontamination Waste Treatment Tank (DWTT) or the Recycle Collection Tank (RCT). All recycle streams are currently combined in the RCT and treated with sodium nitrite and sodium hydroxide prior to transfer to the tank farm. Tank Farm space limitations and previous outages in the 2H Evaporator system due to deposition of sodium alumino-silicates have led to evaluation of alternative methods of dealing with the DWPF recycle. One option identified for processing the recycle was a dedicated evaporator to concentrate the recycle stream to allow the solids to be recycled to the DWPF Sludge Receipt and Adjustment Tank (SRAT) and the condensate from this evaporation process to be sent and treated in the Effluent Treatment Plant (ETP). In order to meet process objectives, the recycle stream must be concentrated to 1/30th of the feed volume during the evaporation process. The concentrated stream must be pumpable to the DWPF SRAT vessel and should not precipitate solids to avoid fouling the evaporator vessel and heat transfer coils. The evaporation process must not generate excessive foam and must have a high Decontamination Factor (DF) for many species in the evaporator feed to allow the condensate to be transferred to the ETP. An initial scoping study was completed in 2001 to evaluate the feasibility of the evaporator which concluded that the concentration objectives could be met. This initial study was based on initial estimates of recycle concentration and was based solely on OLI modeling of the evaporation process. The Savannah River National Laboratory (SRNL) has completed additional studies using simulated recycle streams and OLI{reg_sign} simulations. Based on this work, the proposed flowsheet for the recycle evaporator was evaluated for feasibility, evaporator design considerations, and impact on the DWPF process. This work was in accordance with guidance from DWPF-E and was performed in accordance with the Technical Task and Quality Assurance Plan.« less

Definition of an Acceptable Glass composition Region (AGCR) via an Index System and a Partitioning Function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peeler, D. K.; Taylor, A. S.; Edwards, T.B.

2005-06-26

The objective of this investigation was to appeal to the available ComPro{trademark} database of glass compositions and measured PCTs that have been generated in the study of High Level Waste (HLW)/Low Activity Waste (LAW) glasses to define an Acceptable Glass Composition Region (AGCR). The term AGCR refers to a glass composition region in which the durability response (as defined by the Product Consistency Test (PCT)) is less than some pre-defined, acceptable value that satisfies the Waste Acceptance Product Specifications (WAPS)--a value of 10 g/L was selected for this study. To assess the effectiveness of a specific classification or index systemmore » to differentiate between acceptable and unacceptable glasses, two types of errors (Type I and Type II errors) were monitored. A Type I error reflects that a glass with an acceptable durability response (i.e., a measured NL [B] < 10 g/L) is classified as unacceptable by the system of composition-based constraints. A Type II error occurs when a glass with an unacceptable durability response is classified as acceptable by the system of constraints. Over the course of the efforts to meet this objective, two approaches were assessed. The first (referred to as the ''Index System'') was based on the use of an evolving system of compositional constraints which were used to explore the possibility of defining an AGCR. This approach was primarily based on ''glass science'' insight to establish the compositional constraints. Assessments of the Brewer and Taylor Index Systems did not result in the definition of an AGCR. Although the Taylor Index System minimized Type I errors which allowed access to composition regions of interest to improve melt rate or increase waste loadings for DWPF as compared to the current durability model, Type II errors were also committed. In the context of the application of a particular classification system in the process control system, Type II errors are much more serious than Type I errors. A Type I error only reflects that the particular constraint system being used is overly conservative (i.e., its application restricts access to glasses that have an acceptable measured durability response). A Type II error results in a more serious misclassification that could result in allowing the transfer of a Slurry Mix Evaporator (SME) batch to the melter, which is predicted to produce a durable product based on the specific system applied but in reality does not meet the defined ''acceptability'' criteria. More specifically, a nondurable product could be produced in DWPF. Given the presence of Type II errors, the Index System approach was deemed inadequate for further implementation consideration at the DWPF. The second approach (the JMP partitioning process) was purely data driven and empirically derived--glass science was not a factor. In this approach, the collection of composition--durability data in ComPro was sequentially partitioned or split based on the best available specific criteria and variables. More specifically, the JMP software chose the oxide (Al{sub 2}O{sub 3} for this dataset) that most effectively partitions the PCT responses (NL [B]'s)--perhaps not 100% effective based on a single oxide. Based on this initial split, a second request was made to split a particular set of the ''Y'' values (good or bad PCTs based on the 10 g/L limit) based on the next most critical ''X'' variable. This ''splitting'' or ''partitioning'' process was repeated until an AGCR was defined based on the use of only 3 oxides (Al{sub 2}O{sub 3}, CaO, and MgO) and critical values of > 3.75 wt% Al{sub 2}O{sub 3}, {ge} 0.616 wt% CaO, and < 3.521 wt% MgO. Using this set of criteria, the ComPro database was partitioned in which no Type II errors were committed. The automated partitioning function screened or removed 978 of the 2406 ComPro glasses which did cause some initial concerns regarding excessive conservatism regardless of its ability to identify an AGCR. However, a preliminary review of glasses within the 1428 ''acceptable'' glasses defining the ACGR includes glass systems of interest to support the accelerated mission.« less

DWPF SIMULANT CPC STUDIES FOR SB7B

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koopman, D.

2011-11-01

Lab-scale DWPF simulations of Sludge Batch 7b (SB7b) processing were performed. Testing was performed at the Savannah River National Laboratory - Aiken County Technology Laboratory (SRNL-ACTL). The primary goal of the simulations was to define a likely operating window for acid stoichiometry for the DWPF Sludge Receipt and Adjustment Tank (SRAT). In addition, the testing established conditions for the SRNL Shielded Cells qualification simulation of SB7b-Tank 40 blend, supported validation of the current glass redox model, and validated the coupled process flowsheet at the nominal acid stoichiometry. An acid window of 105-140% by the Koopman minimum acid (KMA) equation (107-142%more » DWPF Hsu equation) worked for the sludge-only flowsheet. Nitrite was present in the SRAT product for the 105% KMA run at 366 mg/kg, while SME cycle hydrogen reached 94% of the DWPF Slurry Mix Evaporator (SME) cycle limit in the 140% KMA run. The window was determined for sludge with added caustic (0.28M additional base, or roughly 12,000 gallons 50% NaOH to 820,000 gallons waste slurry). A suitable processing window appears to be 107-130% DWPF acid equation for sludge-only processing allowing some conservatism for the mapping of lab-scale simulant data to full-scale real waste processing including potentially non-conservative noble metal and mercury concentrations. This window should be usable with or without the addition of up to 7,000 gallons of caustic to the batch. The window could potentially be wider if caustic is not added to SB7b. It is recommended that DWPF begin processing SB7b at 115% stoichiometry using the current DWPF equation. The factor could be increased if necessary, but changes should be made with caution and in small increments. DWPF should not concentrate past 48 wt.% total solids in the SME cycle if moderate hydrogen generation is occurring simultaneously. The coupled flowsheet simulation made more hydrogen in the SRAT and SME cycles than the sludge-only run with the same acid stoichiometric factor. The slow acid addition in MCU seemed to alter the reactions that consumed the small excess acid present such that hydrogen generation was promoted relative to sludge-only processing. The coupled test reached higher wt.% total solids, and this likely contributed to the SME cycle hydrogen limit being exceeded at 110% KMA. It is clear from the trends in the SME processing GC data, however, that the frit slurry formic acid contributed to driving the hydrogen generation rate above the SME cycle limit. Hydrogen generation rates after the second frit addition generally exceeded those after the first frit addition. SRAT formate loss increased with increasing acid stoichiometry (15% to 35%). A substantial nitrate gain which was observed to have occurred after acid addition (and nitrite destruction) was reversed to a net nitrate loss in runs with higher acid stoichiometry (nitrate in SRAT product less than sum of sludge nitrate and added nitric acid). Increased ammonium ion formation was also indicated in the runs with nitrate loss. Oxalate loss on the order 20% was indicated in three of the four acid stoichiometry runs and in the coupled flowsheet run. The minimum acid stoichiometry run had no indicated loss. The losses were of the same order as the official analytical uncertainty of the oxalate concentration measurement, but were not randomly distributed about zero loss, so some actual loss was likely occurring. Based on the entire set of SB7b test data, it is recommended that DWPF avoid concentrating additional sludge solids in single SRAT batches to limit the concentrations of noble metals to SB7a processing levels (on a grams noble metal per SRAT batch basis). It is also recommended that DWPF drop the formic acid addition that accompanies the process frit 418 additions, since SME cycle data showed considerable catalytic activity for hydrogen generation from this additional acid (about 5% increase in stoichiometry occurred from the frit formic acid). Frit 418 also does not appear to need formic acid addition to prevent gel formation in the frit slurry. Simulant processing was successful using 100 ppm of 747 antifoam added prior to nitric acid instead of 200 ppm. This is a potential area for DWPF to cut antifoam usage in any future test program. An additional 100 ppm was added before formic acid addition. Foaming during formic acid addition was not observed. No build-up of oily or waxy material was observed in the off-gas equipment. Lab-scale mercury stripping behavior was similar to SB6 and SB7a. More mercury was unaccounted for as the acid stoichiometry increased.« less

Baseline LAW Glass Formulation Testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, Albert A.; Mooers, Cavin; Bazemore, Gina

2013-06-13

The major objective of the baseline glass formulation work was to develop and select glass formulations that are compliant with contractual and processing requirements for each of the LAW waste streams. Other objectives of the work included preparation and characterization of glasses with respect to the properties of interest, optimization of sulfate loading in the glasses, evaluation of ability to achieve waste loading limits, testing to demonstrate compatibility of glass melts with melter materials of construction, development of glass formulations to support ILAW qualification activities, and identification of glass formulation issues with respect to contract specifications and processing requirements.

Characterization of DWPF recycle condensate materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C. J.; Adamson, D. J.; King, W. D.

2015-04-01

A Defense Waste Processing Facility (DWPF) Recycle Condensate Tank (RCT) sample was delivered to the Savannah River National Laboratory (SRNL) for characterization with particular interest in the concentration of I-129, U-233, U-235, total U, and total Pu. Since a portion of Salt Batch 8 will contain DWPF recycle materials, the concentration of I-129 is important to understand for salt batch planning purposes. The chemical and physical characterizations are also needed as input to the interpretation of future work aimed at determining the propensity of the RCT material to foam, and methods to remediate any foaming potential. According to DWPF themore » Tank Farm 2H evaporator has experienced foaming while processing DWPF recycle materials. The characterization work on the RCT samples has been completed and is reported here.« less

Final Report. Baseline LAW Glass Formulation Testing, VSL-03R3460-1, Rev. 0

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muller, Isabelle S.; Pegg, Ian L.; Gan, Hao

2015-06-18

The major objective of the baseline glass formulation work was to develop and select glass formulations that are compliant with contractual and processing requirements for each of the LAW waste streams. Other objectives of the work included preparation and characterization of glasses with respect to the properties of interest, optimization of sulfate loading in the glasses, evaluation of ability to achieve waste loading limits, testing to demonstrate compatibility of glass melts with melter materials of construction, development of glass formulations to support ILAW qualification activities, and identification of glass formulation issues with respect to contract specifications and processing requirements.

EVALUATION OF REQUIREMENTS FOR THE DWPF HIGHER CAPACITY CANISTER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, D.; Estochen, E.; Jordan, J.

2014-08-05

The Defense Waste Processing Facility (DWPF) is considering the option to increase canister glass capacity by reducing the wall thickness of the current production canister. This design has been designated as the DWPF Higher Capacity Canister (HCC). A significant decrease in the number of canisters processed during the life of the facility would be achieved if the HCC were implemented leading to a reduced overall reduction in life cycle costs. Prior to implementation of the change, Savannah River National Laboratory (SRNL) was requested to conduct an evaluation of the potential impacts. The specific areas of interest included loading and deformationmore » of the canister during the filling process. Additionally, the effect of the reduced wall thickness on corrosion and material compatibility needed to be addressed. Finally the integrity of the canister during decontamination and other handling steps needed to be determined. The initial request regarding canister fabrication was later addressed in an alternate study. A preliminary review of canister requirements and previous testing was conducted prior to determining the testing approach. Thermal and stress models were developed to predict the forces on the canister during the pouring and cooling process. The thermal model shows the HCC increasing and decreasing in temperature at a slightly faster rate than the original. The HCC is shown to have a 3°F ΔT between the internal and outer surfaces versus a 5°F ΔT for the original design. The stress model indicates strain values ranging from 1.9% to 2.9% for the standard canister and 2.5% to 3.1% for the HCC. These values are dependent on the glass level relative to the thickness transition between the top head and the canister wall. This information, along with field readings, was used to set up environmental test conditions for corrosion studies. Small 304-L canisters were filled with glass and subjected to accelerated environmental testing for 3 months. No evidence of stress corrosion cracking was indicated on either the canisters or U-bend coupons. Calculations and finite element modeling were used to determine forces over a range of handling conditions along with possible forces during decontamination. While expected reductions in some physical characteristics were found in the HCC, none were found to be significant when compared to the required values necessary to perform its intended function. Based on this study and a review of successful testing of thinner canisters at West Valley Demonstration Project (WVDP), the mechanical properties obtained with the thinner wall do not significantly undermine the ability of the canister to perform its intended function.« less

Testing of the Defense Waste Processing Facility Cold Chemical Dissolution Method in Sludge Batch 9 Qualification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, T.; Pareizs, J.; Coleman, C.

For each sludge batch that is processed in the Defense Waste Processing Facility (DWPF), the Savannah River National Laboratory (SRNL) tests the applicability of the digestion methods used by the DWPF Laboratory for elemental analysis of Sludge Receipt and Adjustment Tank (SRAT) Receipt samples and SRAT Product process control samples. DWPF SRAT samples are typically dissolved using a method referred to as the DWPF Cold Chemical or Cold Chem Method (CC), (see DWPF Procedure SW4- 15.201). Testing indicates that the CC method produced mixed results. The CC method did not result in complete dissolution of either the SRAT Receipt ormore » SRAT Product with some fine, dark solids remaining. However, elemental analyses did not reveal extreme biases for the major elements in the sludge when compared with analyses obtained following dissolution by hot aqua regia (AR) or sodium peroxide fusion (PF) methods. The CC elemental analyses agreed with the AR and PF methods well enough that it should be adequate for routine process control analyses in the DWPF after much more extensive side-by-side tests of the CC method and the PF method are performed on the first 10 SRAT cycles of the Sludge Batch 9 (SB9) campaign. The DWPF Laboratory should continue with their plans for further tests of the CC method during these 10 SRAT cycles.« less

VERIFICATION OF THE DEFENSE WASTE PROCESSING FACILITY PROCESS DIGESTION METHOD FOR THE SLUDGE BATCH 6 QUALIFICATION SAMPLE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Click, D.; Jones, M.; Edwards, T.

2010-06-09

For each sludge batch that is processed in the Defense Waste Processing Facility (DWPF), the Savannah River National Laboratory (SRNL) confirms applicability of the digestion method to be used by the DWPF lab for elemental analysis of Sludge Receipt and Adjustment Tank (SRAT) receipt samples and SRAT product process control samples.1 DWPF SRAT samples are typically dissolved using a room temperature HF-HNO3 acid dissolution (i.e., DWPF Cold Chem (CC) Method, see DWPF Procedure SW4-15.201) and then analyzed by inductively coupled plasma - atomic emission spectroscopy (ICPAES). In addition to the CC method confirmation, the DWPF lab's mercury (Hg) digestion methodmore » was also evaluated for applicability to SB6 (see DWPF procedure 'Mercury System Operating Manual', Manual: SW4-15.204. Section 6.1, Revision 5, Effective date: 12-04-03). This report contains the results and comparison of data generated from performing the Aqua Regia (AR), Sodium Peroxide/Hydroxide Fusion (PF) and DWPF Cold Chem (CC) method digestion of Sludge Batch 6 (SB6) SRAT Receipt and SB6 SRAT Product samples. For validation of the DWPF lab's Hg method, only SRAT receipt material was used and compared to AR digestion results. The SB6 SRAT Receipt and SB6 SRAT Product samples were prepared in the SRNL Shielded Cells, and the SRAT Receipt material is representative of the sludge that constitutes the SB6 Batch or qualification composition. This is the sludge in Tank 51 that is to be transferred into Tank 40, which will contain the heel of Sludge Batch 5 (SB5), to form the SB6 Blend composition. In addition to the 16 elements currently measured by the DWPF, this report includes Hg and thorium (Th) data (Th comprising {approx}2.5 - 3 Wt% of the total solids in SRAT Receipt and SRAT Product, respectively) and provides specific details of ICP-AES analysis of Th. Thorium was found to interfere with the U 367.007 nm emission line, and an inter-element correction (IEC) had to be applied to U data, which is also discussed. The results for any one particular element should not be used in any way to identify the form or speciation of a particular element without support from XRD analysis or used to estimate ratios of compounds in the sludge.« less

Long-term high-level waste technology. Composite report

NASA Astrophysics Data System (ADS)

Cornman, W. R.

1981-12-01

Research and development studies on the immobilization of high-level wastes from the chemical reprocessing of nuclear reactor fuels are summarized. The reports are grouped under the following tasks: (1) program management and support; (2) waste preparation; (3) waste fixation; and (4) final handling. Some of the highlights are: leaching properties were obtained for titanate and tailored ceramic materials being developed at ICPP to immobilize zirconia calcine; comparative leach tests, hot-cell tests, and process evaluations were conducted of waste form alternatives to borosilicate glass for the immobilization of SRP high-level wastes, experiments were run at ANL to qualify neutron activation analysis and radioactive tracers for measuring leach rates from simulated waste glasses; comparative leach test samples of SYNROC D were prepared, characterized, and tested at LLNL; encapsulation of glass marbles with lead or lead alloys was demonstrated on an engineering scale at PNL; a canister for reference Commercial HLW was designed at PNL; a study of the optimization of salt-crete was completed at SRL; a risk assessment showed that an investment for tornado dampers in the interim storage building of the DWPF is unjustified.

Nuclear Waste: Defense Waste Processing Facility-Cost, Schedule, and Technical Issues.

DTIC Science & Technology

1992-06-17

gallons of high-level radioactive waste stored in underground tanks at the savannah major facility involved Is the Defense Waste Processing Facility ( DwPF ...As a result of concerns about potential problems with the DWPF and delays in its scheduled start-up, the Chairman of the Environment, Energy, and...Natural Resources Subcommittee, House Committee on Government Operations, asked GAO to review the status of the DWPF and other facilities. This report

DETERMINATION OF REPORTABLE RADIONUCLIDES FOR DWPF SLUDGE BATCH 7B (MACROBATCH 9)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crawford, C. L.; Diprete, D. P.

The Waste Acceptance Product Specifications (WAPS) 1.2 require that “The Producer shall report the inventory of radionuclides (in Curies) that have half-lives longer than 10 years and that are, or will be, present in concentrations greater than 0.05 percent of the total inventory for each waste type indexed to the years 2015 and 3115”. As part of the strategy to comply with WAPS 1.2, the Defense Waste Processing Facility (DWPF) will report for each waste type, all radionuclides (with half-lives greater than 10 years) that have concentrations greater than 0.01 percent of the total inventory from time of production throughmore » the 1100 year period from 2015 through 3115. The initial listing of radionuclides to be included is based on the design-basis glass as identified in the Waste Form Compliance Plan (WCP) and Waste Form Qualification Report (WQR). However, it is required that this list be expanded if other radionuclides with half-lives greater than 10 years are identified that may meet the greater than 0.01% criterion for Curie content. Specification 1.6 of the WAPS, International Atomic Energy Agency (IAEA) Safeguards Reporting for High Level Waste (HLW), requires that the ratio by weights of the following uranium and plutonium isotopes be reported: U-233, U-234, U-235, U-236, U-238, Pu-238, Pu-239, Pu-240, Pu-241, and Pu- 242. Therefore, the complete set of reportable radionuclides must also include this set of U and Pu isotopes. The DWPF is receiving radioactive sludge slurry from HLW Tank 40. The radioactive sludge slurry in Tank 40 is a blend of the heel from Sludge Batch 7a (SB7a) and Sludge Batch 7b (SB7b) that was transferred to Tank 40 from Tank 51. The blend of sludge in Tank 40 is also referred to as Macrobatch 9 (MB9). This report develops the list of reportable radionuclides and associated activities as a function of time. The DWPF will use this list and the activities as one of the inputs for the development of the Production Records that relate to radionuclide inventory. This work was initiated through Technical Task Request (TTR) HLW-DWPF-TTR-2011-0004; Rev. 0 entitled Sludge Batch 7b Qualification Studies. Specifically, this report details results from performing Subtask II, Item 2 of the TTR and, in part, meets Deliverable 6 of the TTR. The work was performed following the Task Technical and Quality Assurance Plan (TTQAP), SRNL-RP-2011-00247, Rev. 0 and Analytical Study Plan (ASP), SRNL-RP-2011-00248, Rev. 0. In order to determine the reportable radionuclides for SB7b (MB9), a list of radioisotopes that may meet the criteria as specified by the Department of Energy’s (DOE) WAPS was developed. All radioactive U- 235 fission products and all radioactive activation products that could be in the SRS HLW were considered. In addition, all U and Pu isotopes identified in WAPS 1.6 were included in the list. This list was then evaluated and some isotopes were excluded from the projection calculations. Based on measurements and analytical detection limits, 27 radionuclides have been identified as reportable for DWPF SB7b as specified by WAPS 1.2. The WCP and WQR require that all of the radionuclides present in the Design Basis glass be considered as the initial set of reportable radionuclides. For SB7b, all of the radionuclides in the Design Basis glass are reportable except for three radionuclides: Pd-107, Cs-135, and Th-230. At no time during the 1100- year period between 2015 and 3115 did any of these three radionuclides contribute to more than 0.01% of the radioactivity on a Curie basis. Two additional uranium isotopes (U-235 and -236) must be added to the list of reportable radionuclides in order to meet WAPS 1.6. All of the Pu isotopes (Pu-238, -239, -240, -241, and -242) and other U isotopes (U-233, -234, and -238) identified in WAPS 1.6 were already determined to be reportable according to WAPS 1.2 This brings the total number of reportable radionuclides for SB7b to 29. The radionuclide measurements made for SB7b are similar to those performed in the previous SB7a MB8 work. Some method development/refinement occurred during the conduct of these measurements, leading to lower detection limits and more accurate measurement of some isotopes than was previously possible. Improvement in the analytical measurements will likely continue, and this in turn should lead to improved detection limit values for some radionuclides and actual measurements for still others.« less

Determination Of Reportable Radionuclides For DWPF Sludge Batch 7B (Macrobatch 9)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crawford, C. L.; DiPrete, D. P.

The Waste Acceptance Product Specifications (WAPS) 1.2 require that “The Producer shall report the inventory of radionuclides (in Curies) that have half-lives longer than 10 years and that are, or will be, present in concentrations greater than 0.05 percent of the total inventory for each waste type indexed to the years 2015 and 3115”. As part of the strategy to comply with WAPS 1.2, the Defense Waste Processing Facility (DWPF) will report for each waste type, all radionuclides (with half-lives greater than 10 years) that have concentrations greater than 0.01 percent of the total inventory from time of production throughmore » the 1100 year period from 2015 through 3115. The initial listing of radionuclides to be included is based on the design-basis glass as identified in the Waste Form Compliance Plan (WCP) and Waste Form Qualification Report (WQR). However, it is required that this list be expanded if other radionuclides with half-lives greater than 10 years are identified that may meet the greater than 0.01% criterion for Curie content. Specification 1.6 of the WAPS, International Atomic Energy Agency (IAEA) Safeguards Reporting for High Level Waste (HLW), requires that the ratio by weights of the following uranium and plutonium isotopes be reported: U-233, U-234, U-235, U-236, U-238, Pu-238, Pu-239, Pu-240, Pu-241, and Pu-242. Therefore, the complete set of reportable radionuclides must also include this set of U and Pu isotopes. The DWPF is receiving radioactive sludge slurry from HLW Tank 40. The radioactive sludge slurry in Tank 40 is a blend of the heel from Sludge Batch 7a (SB7a) and Sludge Batch 7b (SB7b) that was transferred to Tank 40 from Tank 51. The blend of sludge in Tank 40 is also referred to as Macrobatch 9 (MB9). This report develops the list of reportable radionuclides and associated activities as a function of time. The DWPF will use this list and the activities as one of the inputs for the development of the Production Records that relate to radionuclide inventory. This work was initiated through Technical Task Request (TTR) HLW-DWPF-TTR-2011-0004; Rev. 0 entitled Sludge Batch 7b Qualification Studies. Specifically, this report details results from performing Subtask II, Item 2 of the TTR and, in part, meets Deliverable 6 of the TTR. The work was performed following the Task Technical and Quality Assurance Plan (TTQAP), SRNL-RP-2011-00247, Rev. 0 and Analytical Study Plan (ASP), SRNL-RP-2011-00248, Rev. 0. In order to determine the reportable radionuclides for SB7b (MB9), a list of radioisotopes that may meet the criteria as specified by the Department of Energy’s (DOE) WAPS was developed. All radioactive U-235 fission products and all radioactive activation products that could be in the SRS HLW were considered. In addition, all U and Pu isotopes identified in WAPS 1.6 were included in the list. This list was then evaluated and some isotopes were excluded from the projection calculations. Based on measurements and analytical detection limits, 27 radionuclides have been identified as reportable for DWPF SB7b as specified by WAPS 1.2. The WCP and WQR require that all of the radionuclides present in the Design Basis glass be considered as the initial set of reportable radionuclides. For SB7b, all of the radionuclides in the Design Basis glass are reportable except for three radionuclides: Pd-107, Cs-135, and Th-230. At no time during the 1100-year period between 2015 and 3115 did any of these three radionuclides contribute to more than 0.01% of the radioactivity on a Curie basis. Two additional uranium isotopes (U-235 and -236) must be added to the list of reportable radionuclides in order to meet WAPS 1.6. All of the Pu isotopes (Pu-238, -239, -240, -241, and -242) and other U isotopes (U-233, -234, and -238) identified in WAPS 1.6 were already determined to be reportable according to WAPS 1.2 This brings the total number of reportable radionuclides for SB7b to 29. The radionuclide measurements made for SB7b are similar to those performed in the previous SB7a MB8 work. Some method development/refinement occurred during the conduct of these measurements, leading to lower detection limits and more accurate measurement of some isotopes than was previously possible. Improvement in the analytical measurements will likely continue, and this in turn should lead to improved detection limit values for some radionuclides and actual measurements for still others.« less

Glycolic acid physical properties and impurities assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, D. P.; Pickenheim, B. R.; Bibler, N. E.

This document has been revised due to recent information that the glycolic acid used in Savannah River National Laboratory (SRNL) experiments contains both formaldehyde and methoxyacetic acid. These impurities were in the glycolic acid used in the testing included in this report and in subsequent testing using DuPont (now called Chemours) supplied Technical Grade 70 wt% glycolic acid. However, these impurities were not reported in earlier revisions. Additional data concerning the properties of glycolic acid have also been added to this report. The Defense Waste Processing Facility (DWPF) is planning to implement a nitric-glycolic acid flowsheets to increase attainment tomore » meet closure commitment dates during Sludge Batch 9. In fiscal year 2009, SRNL was requested to determine the physical properties of formic and glycolic acid blends. Blends of formic acid in glycolic acid were prepared and their physical properties tested. Increasing amounts of glycolic acid led to increases in blend density, viscosity and surface tension as compared to the 90 wt% formic acid that is currently used at DWPF. These increases are small, however, and are not expected to present any difficulties in terms of processing. The effect of sulfur impurities in Technical Grade glycolic acid was studied for its impact on DWPF glass quality. While the glycolic acid specification allows for more sulfate than the current formic acid specification, the ultimate impact is expected to be on the order of 0.033 wt% sulfur in glass. Note that lower sulfur content glycolic acid could likely be procured at some increased cost if deemed necessary. A paper study on the effects of radiation on glycolic acid was performed. The analysis indicates that substitution of glycolic acid for formic acid would not increase the radiolytic production rate of H2 and cause an adverse effect in the Slurry Receipt and Adjustment Tank (SRAT) or Slurry Mix Evaporator (SME) process. It has been cited that glycolic acid solutions that are depleted of O2 when subjected to large radiation doses produced considerable quantities of a non-diffusive polymeric material. Considering a constant air purge is maintained in the SRAT and the solution is continuously mixed, oxygen depletion seems unlikely, however, if this polymer is formed in the SRAT solution, the rheology of the solution may be affected and pumping of the solution may be hindered. However, an irradiation test with a simulated SRAT product supernate containing glycolic acid in an oxygen depleted atmosphere found no evidence of polymerization.« less

Infrasound Detection of Rocket Launches

DTIC Science & Technology

2000-09-01

infrasound pressure, and λ and µ are the Lame and shear modulii. Seismic data was available from the IRIS data center for the seismic station DWPF ...the bandwidth of interest. Figure 4 shows a recording of STS-93 (07/24/99 04:31:00GMT) at DWPF (97 km). The largest seismic amplitudes are consistent...lasts ~400 seconds. The dominant frequency (~4 Hz) at DWPF is consistent with the long-range infrasound signals observed at DLIAR. Figure 3. Seismic

Glass Property Models, Constraints, and Formulation Approaches for Vitrification of High-Level Nuclear Wastes at the US Hanford Site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Dong-Sang

2015-03-02

The legacy nuclear wastes stored in underground tanks at the US Department of Energy’s Hanford site is planned to be separated into high-level waste and low-activity waste fractions and vitrified separately. Formulating optimized glass compositions that maximize the waste loading in glass is critical for successful and economical treatment and immobilization of nuclear wastes. Glass property-composition models have been developed and applied to formulate glass compositions for various objectives for the past several decades. The property models with associated uncertainties and combined with composition and property constraints have been used to develop preliminary glass formulation algorithms designed for vitrification processmore » control and waste form qualification at the planned waste vitrification plant. This paper provides an overview of current status of glass property-composition models, constraints applicable to Hanford waste vitrification, and glass formulation approaches that have been developed for vitrification of hazardous and highly radioactive wastes stored at the Hanford site.« less

Results for the DWPF Slurry Mix Evaporator Condensate Tank, Off Gas Condensate Tank, And Recycle Collection Tank Samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

TERRI, FELLINGER

2004-12-21

The Defense Waste Processing Facility, DWPF, currently generates approximately 1.4 million gallons of recycle water per year during Sludge-Only operations. DWPF has minimized condensate generation to 1.4 million gallons by not operating the Steam Atomized Scrubbers, SASs, for the melter off gas system. By not operating the SASs, DWPF has reduced the total volume by approximately 800,000 gallons of condensate per year. Currently, the recycle stream is sent to back to the Tank Farm and processed through the 2H Evaporator system. To alleviate the load on the 2H Evaporator system, an acid evaporator design is being considered as an alternatemore » processing and/or concentration method for the DWPF recycle stream. In order to support this alternate processing option, the DWPF has requested that the chemical and radionuclide compositions of the Off Gas Condensate Tank, OGCT, Slurry Mix Evaporator Condensate Tank, SMECT, Recycle Collection Tank, RCT, and the Decontamination Waste Treatment Tank, DWTT, be determined as a part of the process development work for the acid evaporator design. Samples have been retrieved from the OGCT, RCT, and SMECT and have been sent to the Savannah River National Laboratory, SRNL for this characterization. The DWTT samples have been recently shipped to SRNL. The results for the DWTT samples will be issued at later date.« less

Melter Throughput Enhancements for High-Iron HLW

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, A. A.; Gan, Hoa; Joseph, Innocent

2012-12-26

This report describes work performed to develop and test new glass and feed formulations in order to increase glass melting rates in high waste loading glass formulations for HLW with high concentrations of iron. Testing was designed to identify glass and melter feed formulations that optimize waste loading and waste processing rate while meeting all processing and product quality requirements. The work included preparation and characterization of crucible melts to assess melt rate using a vertical gradient furnace system and to develop new formulations with enhanced melt rate. Testing evaluated the effects of waste loading on glass properties and themore » maximum waste loading that can be achieved. The results from crucible-scale testing supported subsequent DuraMelter 100 (DM100) tests designed to examine the effects of enhanced glass and feed formulations on waste processing rate and product quality. The DM100 was selected as the platform for these tests due to its extensive previous use in processing rate determination for various HLW streams and glass compositions.« less

Dentine Tubule Occlusion by Novel Bioactive Glass-Based Toothpastes

PubMed Central

Hill, Robert G.; Chen, Xiaojing

2018-01-01

There are numerous over-the-counter (OTC) and professionally applied (in-office) products and techniques currently available for the treatment of dentine hypersensitivity (DH), but more recently, the use of bioactive glasses in toothpaste formulations have been advocated as a possible solution to managing DH. Aim. The aim of the present study, therefore, was to compare several bioactive glass formulations to investigate their effectiveness in an established in vitro model. Materials and Methods. A 45S5 glass was synthesized in the laboratory together with several other glass formulations: (1) a mixed glass (fluoride and chloride), (2) BioMinF, (3) a chloride glass, and (4) an amorphous chloride glass. The glass powders were formulated into five different toothpaste formulations. Dentine discs were sectioned from extracted human teeth and prepared for the investigation by removing the cutting debris (smear layer) following sectioning using a 6% citric acid solution for 2 minutes. Each disc was halved to provide test and control halves for comparison following the brushing of the five toothpaste formulations onto the test halves for each toothpaste group. Following the toothpaste application, the test discs were immersed in either artificial saliva or exposed to an acid challenge. Results. The dentine samples were analyzed using scanning electron microscopy (SEM), and observation of the SEM images indicated that there was good surface coverage following artificial saliva immersion. Furthermore, although the acid challenge removed the hydroxyapatite layer on the dentine surface for most of the samples, except for the amorphous chloride glass, there was evidence of tubular occlusion in the dentine tubules. Conclusions. The conclusions from the study would suggest that the inclusion of bioactive glass into a toothpaste formulation may be an effective approach to treat DH. PMID:29849637

Compositional Models of Glass/Melt Properties and their Use for Glass Formulation

DOE PAGES

Vienna, John D.; USA, Richland Washington

2014-12-18

Nuclear waste glasses must simultaneously meet a number of criteria related to their processability, product quality, and cost factors. The properties that must be controlled in glass formulation and waste vitrification plant operation tend to vary smoothly with composition allowing for glass property-composition models to be developed and used. Models have been fit to the key glass properties. The properties are transformed so that simple functions of composition (e.g., linear, polynomial, or component ratios) can be used as model forms. The model forms are fit to experimental data designed statistically to efficiently cover the composition space of interest. Examples ofmore » these models are found in literature. The glass property-composition models, their uncertainty definitions, property constraints, and optimality criteria are combined to formulate optimal glass compositions, control composition in vitrification plants, and to qualify waste glasses for disposal. An overview of current glass property-composition modeling techniques is summarized in this paper along with an example of how those models are applied to glass formulation and product qualification at the planned Hanford high-level waste vitrification plant.« less

Ecological studies related to the construction of the Defense Waste Processing Facility on the Savannah River Site. Annual report, FY-1991 and FY-1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scott, D.E.; Chazel, A.C.; Pechmann, J.H.K.

1993-06-01

The Defense Waste Processing Facility (DWPF) was built on the Savannah River Site (SRS) during the mid-1980`s. The Savannah River Ecology Laboratory (SREL) has completed 14 years of ecological studies related to the construction of the DWPF complex. Prior to construction, the 600-acre site (S-Area) contained a Carolina bay and the headwaters of a stream. Research conducted by the SREL has focused primarily on four questions related to these wetlands: (1) Prior to construction, what fauna and flora were present at the DWPF site and at similar, yet undisturbed, alternative sites? (2) By comparing the Carolina bay at the DWPFmore » site (Sun Bay) with an undisturbed control Carolina bay (Rainbow Bay), what effect is construction having on the organisms that inhabited the DWPF site? (3) By comparing control streams with streams on the periphery of the DWPF site, what effect is construction having on the peripheral streams? (4) How effective have efforts been to lessen the impacts of construction, both with respect to erosion control measures and the construction of ``refuge ponds`` as alternative breeding sites for amphibians that formerly bred at Sun Bay? Through the long-term census-taking of biota at the DWPF site and Rainbow Bay, SREL has begun to evaluate the impact of construction on the biota and the effectiveness of mitigation efforts. Similarly, the effects of erosion from the DWPF site on the water quality of S-Area peripheral streams are being assessed. This research provides supporting data relevant to the National Environmental Policy Act (NEPA) of 1969, the Endangered Species Act of 1973, Executive Orders 11988 (Floodplain Management) and 11990 (Protection of Wetlands), and United States Department of Energy (DOE) Guidelines for Compliance with Floodplain/Wetland Environmental Review Requirements (10 CFR 1022).« less

Technical Status Report: Preliminary Glass Formulation Report for INEEL HAW

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peeler, D.; Reamer, I.; Vienna, J.

1998-03-01

This study was performed by a team comprising experts in glass chemistry, glass technology, and statistics at both SRTC and PNNL. This joint effort combined the strengths of each discipline and site to quickly develop a glass formulation for specific INEEL HAW.

Final Report. LAW Glass Formulation to Support AP-101 Actual Waste Testing, VSL-03R3470-2, Rev. 0

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muller, I. S.; Pegg, I. L.; Rielley, Elizabeth

2015-06-22

The main objective of the work was to develop and select a glass formulation for vitrification testing of the actual waste sample of LAW AP-101 at Battelle - Pacific Northwest Division (PNWD). Other objectives of the work included preparation and characterization of glasses to demonstrate compliance with contract and processing requirements, evaluation of the ability to achieve waste loading requirements, testing to demonstrate compatibility of the glass melts with melter materials of construction, comparison of the properties of simulant and actual waste glasses, and identification of glass formulation issues with respect to contract specifications and processing requirements.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prod'homme, A.; Drouvot, O.; Gregory, J.

In 2009, Savannah River Remediation LLC (SRR) assumed the management lead of the Liquid Waste (LW) Program at the Savannah River Site (SRS). The four SRR partners and AREVA, as an integrated subcontractor are performing the ongoing effort to safely and reliably: - Close High Level Waste (HLW) storage tanks; - Maximize waste throughput at the Defense Waste Processing Facility (DWPF); - Process salt waste into stable final waste form; - Manage the HLW liquid waste material stored at SRS. As part of these initiatives, SRR and AREVA deployed a performance management methodology based on Overall Equipment Effectiveness (OEE) atmore » the DWPF in order to support the required production increase. This project took advantage of lessons learned by AREVA through the deployment of Total Productive Maintenance and Visual Management methodologies at the La Hague reprocessing facility in France. The project also took advantage of measurement data collected from different steps of the DWPF process by the SRR team (Melter Engineering, Chemical Process Engineering, Laboratory Operations, Plant Operations). Today the SRR team has a standard method for measuring processing time throughout the facility, a reliable source of objective data for use in decision-making at all levels, and a better balance between engineering department goals and operational goals. Preliminary results show that the deployment of this performance management methodology to the LW program at SRS has already significantly contributed to the DWPF throughput increases and is being deployed in the Saltstone facility. As part of the liquid waste program on Savannah River Site, SRR committed to enhance production throughput of DWPF. Beyond technical modifications implemented at different location of the facility, SRR deployed performance management methodology based on OEE metrics. The implementation benefited from the experience gained by AREVA in its own facilities in France. OEE proved to be a valuable tool in order to support the enhancement program in DWPF by providing unified metrics to measure plant performances, identify bottleneck location, and rank the most time consuming causes from objective data shared between the different groups belonging to the organization. Beyond OEE, the Visual Management tool adapted from the one used at La Hague were also provided in order to further enhance communication within the operating teams. As a result of all the initiatives implemented on DWPF, achieved production has been increased to record rates from FY10 to FY11. It is expected that thanks to the performance management tools now available within DWPF, these results will be sustained and even improved in the future to meet system plan targets. (authors)« less

Nitric-glycolic flowsheet reduction/oxidation (redox) model for the defense waste processing facility (DWPF)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C. M.; Williams, M. S.; Edwards, T. B.

Control of the REDuction/OXidation (REDOX) state of glasses containing high concentrations of transition metals, such as High Level Waste (HLW) glasses, is critical in order to eliminate processing difficulties caused by overly reduced or overly oxidized melts. Operation of a HLW melter at Fe +2/ΣFe ratios of between 0.09 and 0.33, retains radionuclides in the melt and thus the final glass. Specifically, long-lived radioactive 99Tc species are less volatile in the reduced Tc 4+ state as TcO 2 than as NaTcO 4 or Tc 2O 7, and ruthenium radionuclides in the reduced Ru 4+ state are insoluble RuO 2 inmore » the melt which are not as volatile as NaRuO 4 where the Ru is in the +7 oxidation state. Similarly, hazardous volatile Cr 6+ occurs in oxidized melt pools as Na 2CrO 4 or Na 2Cr 2O 7, while the Cr +3 state is less volatile and remains in the melt as NaCrO 2 or precipitates as chrome rich spinels. The melter REDOX control balances the oxidants and reductants from the feed and from processing additives such as antifoam.« less

Final Report - Crystal Settling, Redox, and High Temperature Properties of ORP HLW and LAW Glasses, VSL-09R1510-1, Rev. 0, dated 6/18/09

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, Albert A.; Wang, C.; Gan, H.

2013-11-13

The radioactive tank waste treatment programs at the U. S. Department of Energy (DOE) have featured joule heated ceramic melter technology for the vitrification of high level waste (HLW). The Hanford Tank Waste Treatment and Immobilization Plant (WTP) employs this same basic technology not only for the vitrification of HLW streams but also for the vitrification of Low Activity Waste (LAW) streams. Because of the much greater throughput rates required of the WTP as compared to the vitrification facilities at the West Valley Demonstration Project (WVDP) or the Defense Waste Processing Facility (DWPF), the WTP employs advanced joule heated meltersmore » with forced mixing of the glass pool (bubblers) to improve heat and mass transport and increase melting rates. However, for both HLW and LAW treatment, the ability to increase waste loadings offers the potential to significantly reduce the amount of glass that must be produced and disposed and, therefore, the overall project costs. This report presents the results from a study to investigate several glass property issues related to WTP HLW and LAW vitrification: crystal formation and settling in selected HLW glasses; redox behavior of vanadium and chromium in selected LAW glasses; and key high temperature thermal properties of representative HLW and LAW glasses. The work was conducted according to Test Plans that were prepared for the HLW and LAW scope, respectively. One part of this work thus addresses some of the possible detrimental effects due to considerably higher crystal content in waste glass melts and, in particular, the impact of high crystal contents on the flow property of the glass melt and the settling rate of representative crystalline phases in an environment similar to that of an idling glass melter. Characterization of vanadium redox shifts in representative WTP LAW glasses is the second focal point of this work. The third part of this work focused on key high temperature thermal properties of representative WTP HLW and LAW glasses over a wide range of temperatures, from the melter operating temperature to the glass transition.« less

Actual Waste Demonstration of the Nitric-Glycolic Flowsheet for Sludge Batch 9 Qualification

DOE Office of Scientific and Technical Information (OSTI.GOV)

J. D. Newell; Pareizs, J. M.; Martino, C. J.

For each sludge batch that is processed in the Defense Waste Processing Facility (DWPF), the Savannah River National Laboratory (SRNL) performs qualification testing to demonstrate that the sludge batch is processable. Testing performed by the Savannah River National Laboratory has shown glycolic acid to be effective in replacing the function of formic acid in the DWPF chemical process. The nitric-glycolic flowsheet reduces mercury, significantly lowers the catalytic generation of hydrogen and ammonia which could allow purge reduction in the Sludge Receipt and Adjustment Tank (SRAT), stabilizes the pH and chemistry in the SRAT and the Slurry Mix Evaporator (SME), allowsmore » for effective rheology adjustment, and is favorable with respect to melter flammability. In order to implement the new flowsheet, SRAT and SME cycles, designated SC-18, were performed using a Sludge Batch (SB) 9 slurry blended from SB8 Tank 40H and Tank 51H samples. The SRAT cycle involved adding nitric and glycolic acids to the sludge, refluxing to steam strip mercury, and dewatering to a targeted solids concentration. Data collected during the SRAT cycle included offgas analyses, process temperatures, heat transfer, and pH measurements. The SME cycle demonstrated the addition of glass frit and the replication of six canister decontamination additions. The demonstration concluded with dewatering to a targeted solids concentration. Data collected during the SME cycle included offgas analyses, process temperatures, heat transfer, and pH measurements. Slurry and condensate samples were collected for subsequent analysis« less

Development of Damp-Heat Resistant Self-Primed EVA and Non-EVA Encapsulant Formulations at NREL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pern, F. J.; Jorgensen, G. J.

2005-11-01

Self-primed ethylene-vinyl acetate (EVA) and non-EVA (PMG) encapsulant formulations were developed that have greater resistance to damp heat exposure at 85 deg C and 85% relative humidity (RH) (in terms of adhesion strength to glass substrates) than a commonly used commercial EVA product. The self-primed EVA formulations were developed on the basis of high-performing glass priming formulations that have previously proven to significantly enhance the adhesion strength of unprimed and primed EVA films on glass substrates during damp heat exposure. The PMG encapsulant formulations were based on an ethylene-methylacrylate copolymer containing glycidyl methacrylate.

Characterization of Radioactive Waste Melter Feed Vitrified By Microwave Energy,

DTIC Science & Technology

processed in the Defense Waste Processing Facility ( DWPF ) and poured into stainless steel canisters for eventual disposal in a geologic repository...Vitrification of melter feed samples is necessary for DWPF process and product control. Microwave fusion of melter feed at approximately 12OO deg C for 10

Urban Fire Simulation. Version 2

DTIC Science & Technology

1993-02-01

of the building. In this case the distribution of windows in the tract per floor ( DWPF (FLOORHT)) is calculated under the assumption that the number of...given urban area. The probability that no room on the subject floor will flash over is calculated at label (V) from PNRFOF DWPF (FLOORHT) (1 - FFORF

Glass Property Models and Constraints for Estimating the Glass to be Produced at Hanford by Implementing Current Advanced Glass Formulation Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vienna, John D.; Kim, Dong-Sang; Skorski, Daniel C.

2013-07-01

Recent glass formulation and melter testing data have suggested that significant increases in waste loading in HLW and LAW glasses are possible over current system planning estimates. The data (although limited in some cases) were evaluated to determine a set of constraints and models that could be used to estimate the maximum loading of specific waste compositions in glass. It is recommended that these models and constraints be used to estimate the likely HLW and LAW glass volumes that would result if the current glass formulation studies are successfully completed. It is recognized that some of the models are preliminarymore » in nature and will change in the coming years. Plus the models do not currently address the prediction uncertainties that would be needed before they could be used in plant operations. The models and constraints are only meant to give an indication of rough glass volumes and are not intended to be used in plant operation or waste form qualification activities. A current research program is in place to develop the data, models, and uncertainty descriptions for that purpose. A fundamental tenet underlying the research reported in this document is to try to be less conservative than previous studies when developing constraints for estimating the glass to be produced by implementing current advanced glass formulation efforts. The less conservative approach documented herein should allow for the estimate of glass masses that may be realized if the current efforts in advanced glass formulations are completed over the coming years and are as successful as early indications suggest they may be. Because of this approach there is an unquantifiable uncertainty in the ultimate glass volume projections due to model prediction uncertainties that has to be considered along with other system uncertainties such as waste compositions and amounts to be immobilized, split factors between LAW and HLW, etc.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zamecnik, J. R.; Edwards, T. B.

The conversions of nitrite to nitrate, the destruction of glycolate, and the conversion of glycolate to formate and oxalate were modeled for the Nitric-Glycolic flowsheet using data from Chemical Process Cell (CPC) simulant runs conducted by SRNL from 2011 to 2015. The goal of this work was to develop empirical correlations for these variables versus measureable variables from the chemical process so that these quantities could be predicted a-priori from the sludge composition and measurable processing variables. The need for these predictions arises from the need to predict the REDuction/OXidation (REDOX) state of the glass from the Defense Waste Processingmore » Facility (DWPF) melter. This report summarizes the initial work on these correlations based on the aforementioned data. Further refinement of the models as additional data is collected is recommended.« less

Ecological studies related to construction of the Defense Waste Processing Facility on the Savannah River Site. Annual report, FY 1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1994-11-01

Construction of the Defense Waste Processing Facility (DWPF) on the Savannah River Site (SRS) began during FY-1984. The Savannah River Ecology Laboratory (SREL) has completed 15 years of ecological studies related to the construction of the DWPF complex. Prior to construction, the 600-acre site (S-Area) contained a Carolina bay and the headwaters of a stream. Through the long-term census taking of biota at the DWPF site and Rainbow Bay, SREL has been evaluating the impact of construction on the biota and the effectiveness of mitigation efforts. similarly, the effects of erosion from the DWPF site on the water quality ofmore » S-Area peripheral streams are being assessed. This research provides supporting data relevant to the National Environmental Policy Act (NEPA) of 1969, the Endangered Species Act of 1973, Executive orders 11988 (Floodplain Management) and 11990 (Protection of Wetlands), and United States Department of Energy (DOE) Guidelines for Compliance with Floodplain/Wetland Environmental Review Requirements (10 CFR 1022).« less

Assessment of the impact of TOA partitioning on DWPF off-gas flammability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daniel, W. E.

2013-06-01

An assessment has been made to evaluate the impact on the DWPF melter off-gas flammability of increasing the amount of TOA in the current solvent used in the Modular Caustic-Side Solvent Extraction Process Unit (MCU) process. The results of this study showed that the concentrations of nonvolatile carbon of the current solvent limit (150 ppm) in the Slurry Mix Evaporator (SME) product would be about 7% higher and the nonvolatile hydrogen would be 2% higher than the actual current solvent (126 ppm) with an addition of up to 3 ppm of TOA when the concentration of Isopar L in themore » effluent transfer is controlled below 87 ppm and the volume of MCU effluent transfer to DWPF is limited to 15,000 gallons per Sludge Receipt and Adjustment Tank (SRAT)/SME cycle. Therefore, the DWPF melter off-gas flammability assessment is conservative for up to an additional 3 ppm of TOA in the effluent based on these assumptions. This report documents the calculations performed to reach this conclusion.« less

Characterization of DWPF recycle condensate tank materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C. J.

2015-01-01

A Defense Waste Processing Facility (DWPF) Recycle Condensate Tank (RCT) sample was delivered to the Savannah River National Laboratory (SRNL) for characterization with particular interest in the concentration of I-129, U-233, U-235, total U, and total Pu. Since a portion of Salt Batch 8 will contain DWPF recycle materials, the concentration of I-129 is important to undertand for salt batch planning purposes. The chemical and physical characterizations are also needed as input to the interpretation of future work aimed at determining the propensity of the RCT material to foam, and methods to remediate any foaming potential. According to DWPF themore » Tank Farm 2H evaporator has experienced foaming while processing DWPF recycle materials. The characterization work on the RCT samples has been completed and is reported here. The composition of the Sludge Batch 8 (SB8) RCT material is largely a low base solution of 0.2M NaNO 2 and 0.1M NaNO 3 with a small amount of formate present. Insoluble solids comprise only 0.05 wt.% of the slurry. The solids appear to be largely sludge-like solids based on elemental composition and SEM-EDS analysis. The sample contains an elevated concentration of I-129 (38x) and substantial 59% fraction of Tc-99, as compared to the incoming SB8 Tank 40 feed material. The Hg concentration is 5x, when compared to Fe, of that expected based on sludge carryover. The total U and Pu concentrations are reduced significantly, 0.536 wt.% TS and 2.42E-03 wt.% TS, respectively, with the fissile components, U-233, U-235, Pu-239, and Pu-241, an order of magnitude lower in concentration than those in the SB8 Tank 40 DWPF feed material. This report will be revised to include the foaming study requested in the TTR and outlined in the TTQAP when that work is concluded.« less

Corrosion impact of reductant on DWPF and downstream facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mickalonis, J. I.; Imrich, K. J.; Jantzen, C. M.

2014-12-01

Glycolic acid is being evaluated as an alternate reductant in the preparation of high level waste for the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS). During processing, the glycolic acid is not completely consumed and small quantities of the glycolate anion are carried forward to other high level waste (HLW) facilities. The impact of the glycolate anion on the corrosion of the materials of construction throughout the waste processing system has not been previously evaluated. A literature review had revealed that corrosion data in glycolate-bearing solution applicable to SRS systems were not available. Therefore, testing wasmore » recommended to evaluate the materials of construction of vessels, piping and components within DWPF and downstream facilities. The testing, conducted in non-radioactive simulants, consisted of both accelerated tests (electrochemical and hot-wall) with coupons in laboratory vessels and prototypical tests with coupons immersed in scale-up and mock-up test systems. Eight waste or process streams were identified in which the glycolate anion might impact the performance of the materials of construction. These streams were 70% glycolic acid (DWPF feed vessels and piping), SRAT/SME supernate (Chemical Processing Cell (CPC) vessels and piping), DWPF acidic recycle (DWPF condenser and recycle tanks and piping), basic concentrated recycle (HLW tanks, evaporators, and transfer lines), salt processing (ARP, MCU, and Saltstone tanks and piping), boric acid (MCU separators), and dilute waste (HLW evaporator condensate tanks and transfer line and ETF components). For each stream, high temperature limits and worst-case glycolate concentrations were identified for performing the recommended tests. Test solution chemistries were generally based on analytical results of actual waste samples taken from the various process facilities or of prototypical simulants produced in the laboratory. The materials of construction for most vessels, components and piping were not impacted with the presence of glycolic acid or the impact is not expected to affect the service life. However, the presence of the glycolate anion was found to affect corrosion susceptibility of some materials of construction in the DWPF and downstream facilities, especially at elevated temperatures. The following table summarizes the results of the electrochemical and hot wall testing and indicates expected performance in service with the glycolate anion present.« less

Degradable borate glass polyalkenoate cements.

PubMed

Shen, L; Coughlan, A; Towler, M; Hall, M

2014-04-01

Glass polyalkenoate cements (GPCs) containing aluminum-free borate glasses having the general composition Ag2O-Na2O-CaO-SrO-ZnO-TiO2-B2O3 were evaluated in this work. An initial screening study of sixteen compositions was used to identify regions of glass formation and cement compositions with promising rheological properties. The results of the screening study were used to develop four model borate glass compositions for further study. A second round of rheological experiments was used to identify a preferred GPC formulation for each model glass composition. The model borate glasses containing higher levels of TiO2 (7.5 mol %) tended to have longer working times and shorter setting times. Dissolution behavior of the four model GPC formulations was evaluated by measuring ion release profiles as a function of time. All four GPC formulations showed evidence of incongruent dissolution behavior when considering the relative release profiles of sodium and boron, although the exact dissolution profile of the glass was presumably obscured by the polymeric cement matrix. Compression testing was undertaken to evaluate cement strength over time during immersion in water. The cements containing the borate glass with 7.5 mol % TiO2 had the highest initial compressive strength, ranging between 20 and 30 MPa. No beneficial aging effect was observed-instead, the strength of all four model GPC formulations was found to degrade with time.

WTP Waste Feed Qualification: Glass Fabrication Unit Operation Testing Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, M. E.; Newell, J. D.; Johnson, F. C.

The waste feed qualification program is being developed to protect the Hanford Tank Waste Treatment and Immobilization Plant (WTP) design, safety basis, and technical basis by assuring waste acceptance requirements are met for each staged waste feed campaign prior to transfer from the Tank Operations Contractor to the feed receipt vessels inside the Pretreatment Facility. The Waste Feed Qualification Program Plan describes the three components of waste feed qualification: 1. Demonstrate compliance with the waste acceptance criteria 2. Determine waste processability 3. Test unit operations at laboratory scale. The glass fabrication unit operation is the final step in the processmore » demonstration portion of the waste feed qualification process. This unit operation generally consists of combining each of the waste feed streams (high-level waste (HLW) and low-activity waste (LAW)) with Glass Forming Chemicals (GFCs), fabricating glass coupons, performing chemical composition analysis before and after glass fabrication, measuring hydrogen generation rate either before or after glass former addition, measuring rheological properties before and after glass former addition, and visual observation of the resulting glass coupons. Critical aspects of this unit operation are mixing and sampling of the waste and melter feeds to ensure representative samples are obtained as well as ensuring the fabrication process for the glass coupon is adequate. Testing was performed using a range of simulants (LAW and HLW simulants), and these simulants were mixed with high and low bounding amounts of GFCs to evaluate the mixing, sampling, and glass preparation steps in shielded cells using laboratory techniques. The tests were performed with off-the-shelf equipment at the Savannah River National Laboratory (SRNL) that is similar to equipment used in the SRNL work during qualification of waste feed for the Defense Waste Processing Facility (DWPF) and other waste treatment facilities at the Savannah River Site. It is not expected that the exact equipment used during this testing will be used during the waste feed qualification testing for WTP, but functionally similar equipment will be used such that the techniques demonstrated would be applicable. For example, the mixing apparatus could use any suitable mixer capable of being remoted and achieving similar mixing speeds to those tested.« less

Designing of Hybrid Structured Glass Laminated Transparent Nano Composites through Vacuum infusion Technique

NASA Astrophysics Data System (ADS)

Mukherji, A.; Tarapure, N. D.; Wakure, G. N.

2017-05-01

Glass is the most commonly used transparent material. However, glass is not suitable in applications where low weight, high strength is required. The present invention comprises a method of making a Transparent Glass Laminated Nano composite product. The product contains a Bidirectionally oriented E-Glass Fabric an essentially bidirectional yarn woven fabrics is stretched Bidirectionally by specially fabricated steel frame associated with both co and counter rotating device. These fibers include glass fibrics/cloths or mixtures of any of these. The synthetic fiber may be any synthetic silica based oven waived bi-directional or Uni-directional fabrics. Engaged gear provided in the device develops uniform tension on fabric, in both direction. Nano particle dispersed resin to be used is formulated with their respective curing agents and extenders. The formulated resin contains 0.1-0.5% of Nano additives and the product composed from 5-10 % of Glass fabric, between 10 to 20 % of ordinary glass, and between 60-80 % of the product is the Nano particles dispersed formulated resin, all measured by volume.

SIMULANT DEVELOPMENT FOR SAVANNAH RIVER SITE HIGH LEVEL WASTE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, M; Russell Eibling, R; David Koopman, D

2007-09-04

The Defense Waste Processing Facility (DWPF) at the Savannah River Site vitrifies High Level Waste (HLW) for repository internment. The process consists of three major steps: waste pretreatment, vitrification, and canister decontamination/sealing. The HLW consists of insoluble metal hydroxides (primarily iron, aluminum, magnesium, manganese, and uranium) and soluble sodium salts (carbonate, hydroxide, nitrite, nitrate, and sulfate). The HLW is processed in large batches through DWPF; DWPF has recently completed processing Sludge Batch 3 (SB3) and is currently processing Sludge Batch 4 (SB4). The composition of metal species in SB4 is shown in Table 1 as a function of the ratiomore » of a metal to iron. Simulants remove radioactive species and renormalize the remaining species. Supernate composition is shown in Table 2.« less

Digestion of Crystalline Silicotitanate (CST)

DOE Office of Scientific and Technical Information (OSTI.GOV)

DARREL, WALKER

2004-11-04

Researchers tested methods for chemically dissolving crystalline silicotitanate (CST) as a substitute for mechanical grinding to reduce particle size before vitrification. Testing used the commercially available form of CST, UOP IONSIV(R) IE-911. Reduction of the particle size to a range similar to that of the glass frit used by the Defense Waste Processing Facility (DWPF) could reduce problems with coupling cesium ion exchange to the vitrification process. This study found that IONSIV(R) IE-911 dissolves completely using a combination of acid, hydrogen peroxide, and fluoride ion. Neutralization of the resulting acidic solution precipitates components of the IONSIV(R) IE-911. Digestion requires extremelymore » corrosive conditions. Also, large particles may reform during neutralization, and the initiation and rate of gas generation are unpredictable. Therefore, the method is not recommended as a substitute for mechanical grinding.« less

Short Term Weather Forecasting in Real Time in a Base Weather Station Setting

DTIC Science & Technology

1993-10-01

SMSL DWPF Figure 25. Plot of surface airways observations at 18 UTC, I April 1993. Data is plotted in conventional notation. 35 mu eb 23 -:.-j-32 29292 3...34 38 3 ... .. :......:.. . . O0i-02-93 0600 GMT CLCT TMPF WSYM SMSL DWPF Figure 26. As in Figure 25, except for 06 UTC, 2 April 1993. 36 Figure 27

Nitric-glycolic flowsheet testing for maximum hydrogen generation rate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martino, C. J.; Newell, J. D.; Williams, M. S.

The Defense Waste Processing Facility (DWPF) at the Savannah River Site is developing for implementation a flowsheet with a new reductant to replace formic acid. Glycolic acid has been tested over the past several years and found to effectively replace the function of formic acid in the DWPF chemical process. The nitric-glycolic flowsheet reduces mercury, significantly lowers the chemical generation of hydrogen and ammonia, allows purge reduction in the Sludge Receipt and Adjustment Tank (SRAT), stabilizes the pH and chemistry in the SRAT and the Slurry Mix Evaporator (SME), allows for effective adjustment of the SRAT/SME rheology, and is favorablemore » with respect to melter flammability. The objective of this work was to perform DWPF Chemical Process Cell (CPC) testing at conditions that would bound the catalytic hydrogen production for the nitric-glycolic flowsheet.« less

Recycling of inorganic waste in monolithic and cellular glass-based materials for structural and functional applications.

PubMed

Rincón, Acacio; Marangoni, Mauro; Cetin, Suna; Bernardo, Enrico

2016-07-01

The stabilization of inorganic waste of various nature and origin, in glasses, has been a key strategy for environmental protection for the last decades. When properly formulated, glasses may retain many inorganic contaminants permanently, but it must be acknowledged that some criticism remains, mainly concerning costs and energy use. As a consequence, the sustainability of vitrification largely relies on the conversion of waste glasses into new, usable and marketable glass-based materials, in the form of monolithic and cellular glass-ceramics. The effective conversion in turn depends on the simultaneous control of both starting materials and manufacturing processes. While silica-rich waste favours the obtainment of glass, iron-rich wastes affect the functionalities, influencing the porosity in cellular glass-based materials as well as catalytic, magnetic, optical and electrical properties. Engineered formulations may lead to important reductions of processing times and temperatures, in the transformation of waste-derived glasses into glass-ceramics, or even bring interesting shortcuts. Direct sintering of wastes, combined with recycled glasses, as an example, has been proven as a valid low-cost alternative for glass-ceramic manufacturing, for wastes with limited hazardousness. The present paper is aimed at providing an up-to-date overview of the correlation between formulations, manufacturing technologies and properties of most recent waste-derived, glass-based materials. © 2016 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Literature Review: Assessment of DWPF Melter and Melter Off-gas System Lifetime

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reigel, M.

2015-07-30

Testing to date for the MOC for the Hanford Waste Treatment and Immobilization Plant (WTP) melters is being reviewed with the lessons learned from DWPF in mind and with consideration to the changes in the flowsheet/feed compositions that have occurred since the original testing was performed. This information will be presented in a separate technical report that identifies any potential gaps for WTP processing.

TANK 40 FINAL SB7B CHEMICAL CHARACTERIZATION RESULTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C.

2012-03-15

A sample of Sludge Batch 7b (SB7b) was taken from Tank 40 in order to obtain radionuclide inventory analyses necessary for compliance with the Waste Acceptance Product Specifications (WAPS). The SB7b WAPS sample was also analyzed for chemical composition including noble metals and fissile constituents, and these results are reported here. These analyses along with the WAPS radionuclide analyses will help define the composition of the sludge in Tank 40 that is currently being fed to the Defense Waste Processing Facility (DWPF) as SB7b. At the Savannah River National Laboratory (SRNL) the 3-L Tank 40 SB7b sample was transferred frommore » the shipping container into a 4-L high density polyethylene bottle and solids were allowed to settle over the weekend. Supernate was then siphoned off and circulated through the shipping container to complete the transfer of the sample. Following thorough mixing of the 3-L sample, a 558 g sub-sample was removed. This sub-sample was then utilized for all subsequent analytical samples. Eight separate aliquots of the slurry were digested, four with HNO{sub 3}/HCl (aqua regia) in sealed Teflon{reg_sign} vessels and four with NaOH/Na{sub 2}O{sub 2} (alkali or peroxide fusion) using Zr crucibles. Two Analytical Reference Glass - 1 (ARG-1) standards were digested along with a blank for each preparation. Each aqua regia digestion and blank was diluted to 1:100 mL with deionized water and submitted to Analytical Development (AD) for inductively coupled plasma - atomic emission spectroscopy (ICP-AES) analysis, inductively coupled plasma - mass spectrometry (ICP-MS) analysis, atomic absorption spectroscopy (AA) for As and Se, and cold vapor atomic absorption spectroscopy (CV-AA) for Hg. Equivalent dilutions of the alkali fusion digestions and blank were submitted to AD for ICP-AES analysis. Tank 40 SB7b supernate was collected from a mixed slurry sample in the SRNL Shielded Cells and submitted to AD for ICP-AES, ion chromatography (IC), total base/free OH{sup -}/other base, total inorganic carbon/total organic carbon (TIC/TOC) analyses, and Cs-137 gamma scan. Weighted dilutions of slurry were submitted for IC, TIC/TOC, and total base/free OH{sup -}/other base analyses. Activities for U-233, U-235, and Pu-239 were determined from the ICP-MS data for the aqua regia digestions of the Tank 40 WAPS slurry using the specific activity of each isotope. The Pu-241 value was determined from a Pu-238/-241 method developed by SRNL AD and previously described. The following conclusions were drawn from the analytical results reported here: (1) The ratios of the major elements for the SB7b WAPS sample are different from those measured for the SB7a WAPS sample. There is less Al and Mn relative to Fe than the previous sludge batch. (2) The elemental composition of this sample and the analyses conducted here are reasonable and consistent with DWPF batch data measurements in light of DWPF pre-sample concentration and SRAT product heel contributions to the DWPF SRAT receipt analyses. The element ratios for Al/Fe, Ca/Fe, Mn/Fe, and U/Fe agree within 10% between this work and the DWPF Sludge Receipt and Adjustment Tank (SRAT) receipt analyses. (3) Sulfur in the SB7b WAPS sample is 82% soluble, slightly less than results reported for SB3, SB4, and SB6 samples but unlike the 50% insoluble sulfur observed in the SB5 WAPS sample. In addition, 23% of the soluble sulfur is not present as sulfate in SB7b. (4) The average activities of the fissile isotopes of interest in the SB7b WAPS sample are (in {mu}Ci/g of total dried solids): 4.22E-02 U-233, 6.12E-04 U-235, 1.08E+01 Pu-239, and 5.09E+01 Pu-241. The full radionuclide composition will be reported in a future document. (5) The fission product noble metal and Ag concentrations appear to have largely peaked in previous DWPF sludge batches, with the exception of Ru, which still shows a slight increase in SB7b.« less

Survey of glass plutonium contents and poison selection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plodinec, M.J.; Ramsey, W.G.; Ellison, A.J.G.

1996-05-01

If plutonium and other actinides are to be immobilized in glass, then achieving high concentrations in the glass is desirable. This will lead to reduced costs and more rapid immobilization. However, glasses with high actinide concentrations also bring with them undersirable characteristics, especially a greater concern about nuclear criticality, particularly in a geologic repository. The key to achieving a high concentration of actinide elements in a glass is to formulate the glass so that the solubility of actinides is high. At the same time, the glass must be formulated so that the glass also contains neutron poisons, which will preventmore » criticality during processing and in a geologic repository. In this paper, the solubility of actinides, particularly plutonium, in three types of glasses are discussed. Plutonium solubilities are in the 2-4 wt% range for borosilicate high-level waste (HLW) glasses of the type which will be produced in the US. This type of glass is generally melted at relatively low temperatures, ca. 1150{degrees}C. For this melting temperature, the glass can be reformulated to achieve plutonium solubilities of at least 7 wt%. This low melting temperature is desirable if one must retain volatile cesium-137 in the glass. If one is not concerned about cesium volatility, then glasses can be formulated which can contain much larger amounts of plutonium and other actinides. Plutonium concentrations of at least 15 wt% have been achieved. Thus, there is confidence that high ({ge}5 wt%) concentrations of actinides can be achieved under a variety of conditions.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raszewski, F; Tommy Edwards, T; David Peeler, D

The Liquid Waste Organization (LWO) has requested that the Savannah River National Laboratory (SRNL) to assess the impact of a 100K gallon decant volume from Tank 40H on the existing sludge-only Sludge Batch 4 (SB4)-Frit 510 flowsheet and the coupled operations flowsheet (SB4 with the Actinide Removal Process (ARP)). Another potential SB4 flowsheet modification of interest includes the addition of 3 wt% sodium (on a calcined oxide basis) to a decanted sludge-only or coupled operations flowsheet. These potential SB4 flowsheet modifications could result in significant compositional shifts to the SB4 system. This paper study provides an assessment of the impactmore » of these compositional changes to the projected glass operating windows and to the variability study for the Frit 510-SB4 system. The influence of the compositional changes on melt rate was not assessed in this study nor was it requested. Nominal Stage paper study assessments were completed using the projected compositions for the various flowsheet options coupled with Frit 510 (i.e., variation was not applied to the sludge and frit compositions). In order to gain insight into the impacts of sludge variation and/or frit variation (due to the procurement specifications) on the projected operating windows, three versions of the Variation Stage assessment were performed: (1) the traditional Variation Stage assessment in which the nominal Frit 510 composition was coupled with the extreme vertices (EVs) of each sludge, (2) an assessment of the impact of possible frit variation (within the accepted frit specification tolerances) on each nominal SB4 option, and (3) an assessment of the impact of possible variation in the Frit 510 composition due to the vendor's acceptance specifications coupled with the EVs of each sludge case. The results of the Nominal Stage assessment indicate very little difference among the various flowsheet options. All of the flowsheets provide DWPF with the possibility of targeting waste loadings (WLs) from the low 30s to the low 40s with Frit 510. In general, the Tank 40H decant has a slight negative impact on the operating window, but DWPF still has the ability to target current WLs (34%) and higher WLs if needed. While the decant does not affect practical WL targets in DWPF, melt rate could be reduced due to the lower Na{sub 2}O content. If true, the addition of 3 wt% Na{sub 2}O to the glass system may regain melt rate, assuming that the source of alkali is independent of the impact on melt rate. Coupled operations with Frit 510 via the addition of ARP to the decanted SB4 flowsheet also appears to be viable based on the projected operating windows. The addition of both ARP and 3 wt% Na{sub 2}O to a decanted Tank 40H sludge may be problematic using Frit 510. Although the Nominal Stage assessments provide reasonable operating windows for the SB4 flowsheets being considered with Frit 510, introduction of potential sludge and/or frit compositional variation does have a negative impact. The magnitude of the impact on the projected operating windows is dependent on the specific flowsheet options as well as the applied variation. The results of the traditional Variation Stage assessments indicate that the three proposed Tank 40H decanted flowsheet options (Case No.2--100K gallon decant, Case No.3--100K gallon decant and 3 wt% Na{sub 2}O addition and Case No.4--100K gallon decant and ARP) demonstrate a relatively high degree of robustness to possible sludge variation over WLs of interest with Frit 510. However, the case where the addition of both ARP and 3 wt% Na{sub 2}O is considered was problematic during the traditional Variation Stage assessment. The impact of coupling the frit specifications with the nominal SB4 flowsheet options on the projected operating windows is highly dependent on whether the upper WLs are low viscosity or liquidus temperature limited in the Nominal Stage assessments. Systems that are liquidus temperature limited exhibit a high degree of robustness to the applied frit and sludge variation, while those that are low viscosity limited show significant reductions (6 percentage points) in the upper WLs that can be obtained. When both frit and sludge variations are applied, the paper study results indicate that DWPF could be severely restricted in terms of projected operating windows for the ARP and Na{sub 2}O addition options. An experimental variability study was not performed using the final SB4 composition and Frit 510 since glasses in the ComPro{trademark} data base were identified that bounded the potential operating window of this system. The bounding ARP case was not considered in that assessment. After the flowsheet cases were identified, an electronic search of ComPro{trademark} identified approximately 12 historical glasses within the compositional regions defined by at least one of the five flowsheet options, but the compositional coverage did not appear adequate to bound all cases.« less

SUMMARY OF 2010 DOE EM INTERNATIONAL PROGRAM STUDIES OF WASTE GLASS STRUCTURE AND PROPERTIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fox, K.; Choi, A.; Marra, J.

2011-02-07

Collaborative work between the Savannah River National Laboratory (SRNL) and SIA Radon in Russia was divided among three tasks for calendar year 2010. The first task focused on the study of simplified high level waste glass compositions with the objective of identifying the compositional drivers that lead to crystallization and poor chemical durability. The second task focused on detailed characterization of more complex waste glass compositions with unexpectedly poor chemical durabilities. The third task focused on determining the structure of select high level waste glasses made with varying frit compositions in order to improve models under development for predicting themore » melt rate of the Defense Waste Processing Facility (DWPF) glasses. The majority of these tasks were carried out at SIA Radon. Selection and fabrication of the glass compositions, along with chemical composition measurements and evaluations of durability were carried out at SRNL and are described in this report. SIA Radon provided three summary reports based on the outcome of the three tasks. These reports are included as appendices to this document. Briefly, the result of characterization of the Task 1 glasses may indicate that glass compositions where iron is predominantly tetrahedrally coordinated have more of a tendency to crystallize nepheline or nepheline-like phases. For the Task 2 glasses, the results suggested that the relatively low fraction of tetrahedrally coordinated boron and the relatively low concentrations of Al{sub 2}O{sub 3} available to form [BO{sub 4/2}]{sup -}Me{sup +} and [AlO{sub 4/2}]{sup -}Me{sup +} tetrahedral units are not sufficient to consume all of the alkali ions, and thus these alkali ions are easily leached from the glasses. All of the twelve Task 3 glass compositions were determined to be mainly amorphous, with some minor spinel phases. Several key structural units such as metasilicate chains and rings were identified, which confirms the current modeling approach for the silicate phase. The coordination of aluminum and iron was found to be mainly tetrahedral, with some octahedral iron ions. In all samples, trigonally-coordinated boron was determined to dominate over tetrahedrally-coordinated boron. The results further suggested that BO{sub 4} tetrahedra and BO{sub 3} triangles form complex borate units and may be present as separate constituents. However, no quantification of tetrahedral-to-trigonal boron ratio was made.« less

Actual waste demonstration of the nitric-glycolic flowsheet for sludge batch 9 qualification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Newell, D.; Pareizs, J.; Martino, C.

For each sludge batch that is processed in the Defense Waste Processing Facility (DWPF), the Savannah River National Laboratory (SRNL) performs qualification testing to demonstrate that the sludge batch is processable. Based on the results of this actual-waste qualification and previous simulant studies, SRNL recommends implementation of the nitric-glycolic acid flowsheet in DWPF. Other recommendations resulting from this demonstration are reported in section 5.0.

IMPROVED ANTIFOAM AGENT STUDY END OF YEAR REPORT, EM PROJECT 3.2.3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, D.; Koopman, D.; Newell, J.

2011-09-30

Antifoam 747 is added to minimize foam produced by process gases and water vapor during chemical processing of sludge in the Defense Waste Processing Facility (DWPF). This allows DWPF to maximize acid addition and evaporation rates to minimize the cycle time in the Chemical Processing Cell (CPC). Improvements in DWPF melt rate due to the addition of bubblers in the melter have resulted in the need for further reductions in cycle time in the CPC. This can only be accomplished with an effective antifoam agent. DWPF production was suspended on March 22, 2011 as the result of a Flammable Gasmore » New Information/(NI) Potential Inadequacy in the Safety Analysis (PISA). The issue was that the DWPF melter offgas flammability strategy did not take into account the H and C in the antifoam, potentially flammable components, in the melter feed. It was also determined the DWPF was using much more antifoam than anticipated due to a combination of longer processing in the CPC due to high Hg, longer processing due to Actinide Removal Process (ARP)/Modular Caustic Side Solvent Extraction Unit (MCU) additions, and adding more antifoam than recommended. The resolution to the PISA involved and assessment of the impact of the antifoam on melter flammability and the implementation of a strategy to control additions within acceptable levels. This led to the need to minimize the use of Antifoam 747 in processing beginning in May 2011. DWPF has had limited success in using Antifoam 747 in caustic processing. Since starting up the ARP facility, the ARP product (similar chemically to caustic sludge) is added to the Sludge Receipt and Adjustment Tank (SRAT) at boiling and evaporated to maintain a constant SRAT volume. Although there is very little offgas generated during caustic boiling, there is a large volume of water vapor produced which can lead to foaming. High additions and more frequent use of antifoam are used to mitigate the foaming during caustic boiling. The result of these three issues above is that DWPF had three antifoam needs in FY2011: (1) Determine the cause of the poor Antifoam 747 performance during caustic boiling; (2) Determine the decomposition products of Antifoam 747 during CPC processing; and (3) Improve the effectiveness of Antifoam 747, in order to minimize the amount used. Testing was completed by Illinois Institute of Technology (IIT) and Savannah River National Laboratory (SRNL) researchers to address these questions. The testing results reported were funded by both DWPF and DOE/EM 31. Both sets of results are reported in this document for completeness. The results of this research are summarized: (1) The cause for the poor Antifoam 747 performance during caustic boiling was the high hydrolysis rate, cleaving the antifoam molecule in two, leading to poor antifoam performance. In testing with pH solutions from 1 to 13, the antifoam degraded quickly at a pH < 4 and pH > 10. As the antifoam decomposed it lost its spreading ability (wetting agent performance), which is crucial to its antifoaming performance. During testing of a caustic sludge simulants, there was more foam in tests with added Antifoam 747 than in tests without added antifoam. (2) Analyses were completed to determine the composition of the two antifoam components and Antifoam 747. In addition, the decomposition products of Antifoam 747 were determined during CPC processing of sludge simulants. The main decomposition products were identified primarily as Long Chain Siloxanes, boiling point > 400 C. Total antifoam recovery was 33% by mass. In a subsequent study, various compounds potentially related to antifoam were found using semi-volatile organic analysis and volatile organic analysis on the hexane extractions and hexane rinses. These included siloxanes, trimethyl silanol, methoxy trimethyl silane, hexamethyl disiloxane, aliphatic hydrocarbons, dioctyl phthalate, and emulsifiers. Cumulatively, these species amounted to less than 3% of the antifoam mass. The majority of the antifoam was identified using carbon analysis of the SRAT product (40-80% by mass) and silicon analysis (23-83% by mass) of the condensate. Both studies recommended a better solvent for antifoam and more specific tests for antifoam degradation products than the Si and C analyses used. (3) The DWPF Antifoam 747 Purchase Specification was revised in Month, 2011 with a goal of increasing the quality of Antifoam 747. The purchase specification was changed to specify the manufacturer and product for both components that are blended by Siovation to produce Antifoam 747 for DWPF. Testing of Antifoam produced using both the old and new antifoam specifications perform very similarly in testing. Since the change in purchase specification has not improved antifoam performance, an improved antifoam agent is required.« less

Results from tests of TFL Hydragard sampling loop

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steimke, J.L.

When the Defense Waste Processing Facility (DWPF) is operational, processed radioactive sludge will be transferred in batches to the Slurry Mix Evaporator (SME), where glass frit will be added and the contents concentrated by boiling. Batches of the slurry mixture are transferred from the SME to the Melter Feed Tank (MFT). Hydragard{reg_sign} sampling systems are used on the SME and the MFT for collecting slurry samples in vials for chemical analysis. An accurate replica of the Hydragard sampling system was built and tested in the thermal Fluids Laboratory (TFL) to determine the hydragard accuracy. It was determined that the originalmore » Hydragard valve frequently drew a non-representative sample stream through the sample vial that ranged from frit enriched to frit depleted. The Hydragard valve was modified by moving the plunger and its seat backwards so that the outer surface of the plunger was flush with the inside diameter of the transfer line when the valve was open. The slurry flowing through the vial accurately represented the composition of the slurry in the reservoir for two types of slurries, different dilution factors, a range of transfer flows and a range of vial flows. It was then found that the 15 ml of slurry left in the vial when the Hydragard valve was closed, which is what will be analyzed at DWPF, had a lower ratio of frit to sludge as characterized by the lithium to iron ratio than the slurry flowing through it. The reason for these differences is not understood at this time but it is recommended that additional experimentation be performed with the TFL Hydragard loop to determine the cause.« less

Advanced High-Level Waste Glass Research and Development Plan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peeler, David K.; Vienna, John D.; Schweiger, Michael J.

2015-07-01

The U.S. Department of Energy Office of River Protection (ORP) has implemented an integrated program to increase the loading of Hanford tank wastes in glass while meeting melter lifetime expectancies and process, regulatory, and product quality requirements. The integrated ORP program is focused on providing a technical, science-based foundation from which key decisions can be made regarding the successful operation of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) facilities. The fundamental data stemming from this program will support development of advanced glass formulations, key process control models, and tactical processing strategies to ensure safe and successful operations formore » both the low-activity waste (LAW) and high-level waste (HLW) vitrification facilities with an appreciation toward reducing overall mission life. The purpose of this advanced HLW glass research and development plan is to identify the near-, mid-, and longer-term research and development activities required to develop and validate advanced HLW glasses and their associated models to support facility operations at WTP, including both direct feed and full pretreatment flowsheets. This plan also integrates technical support of facility operations and waste qualification activities to show the interdependence of these activities with the advanced waste glass (AWG) program to support the full WTP mission. Figure ES-1 shows these key ORP programmatic activities and their interfaces with both WTP facility operations and qualification needs. The plan is a living document that will be updated to reflect key advancements and mission strategy changes. The research outlined here is motivated by the potential for substantial economic benefits (e.g., significant increases in waste throughput and reductions in glass volumes) that will be realized when advancements in glass formulation continue and models supporting facility operations are implemented. Developing and applying advanced glass formulations will reduce the cost of Hanford tank waste management by reducing the schedule for tank waste treatment and reducing the amount of HLW glass for storage, transportation, and disposal. Additional benefits will be realized if advanced glasses are developed that demonstrate more tolerance for key components in the waste (such as Al 2O 3, Cr 2O 3, SO 3 and Na 2O) above the currently defined WTP constraints. Tolerating these higher concentrations of key waste loading limiters may reduce the burden on (or even eliminate the need for) leaching to remove Cr and Al and washing to remove excess S and Na from the HLW fraction. Advanced glass formulations may also make direct vitrification of the HLW fraction without significant pretreatment more cost effective. Finally, the advanced glass formulation efforts seek not only to increase waste loading in glass, but also to increase glass production rate. When coupled with higher waste loading, ensuring that all of the advanced glass formulations are processable at or above the current contract processing rate leads to significant improvements in waste throughput (the amount of waste being processed per unit time),which could significantly reduce the overall WTP mission life. The integration of increased waste loading, reduced leaching/washing requirements, and improved melting rates provides a system-wide approach to improve the effectiveness of the WTP process.« less

Integration of the Uncertainties of Anion and TOC Measurements into the Flammability Control Strategy for Sludge Batch 8 at the DWPF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, T. B.

2013-03-14

The Savannah River National Laboratory (SRNL) has been working with the Savannah River Remediation (SRR) Defense Waste Processing Facility (DWPF) in the development and implementation of a flammability control strategy for DWPF’s melter operation during the processing of Sludge Batch 8 (SB8). SRNL’s support has been in response to technical task requests that have been made by SRR’s Waste Solidification Engineering (WSE) organization. The flammability control strategy relies on measurements that are performed on Slurry Mix Evaporator (SME) samples by the DWPF Laboratory. Measurements of nitrate, oxalate, formate, and total organic carbon (TOC) standards generated by the DWPF Laboratory aremore » presented in this report, and an evaluation of the uncertainties of these measurements is provided. The impact of the uncertainties of these measurements on DWPF’s strategy for controlling melter flammability also is evaluated. The strategy includes monitoring each SME batch for its nitrate content and its TOC content relative to the nitrate content and relative to the antifoam additions made during the preparation of the SME batch. A linearized approach for monitoring the relationship between TOC and nitrate is developed, equations are provided that integrate the measurement uncertainties into the flammability control strategy, and sample calculations for these equations are shown to illustrate the impact of the uncertainties on the flammability control strategy.« less

Antifoam degradation testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, D. P.; Zamecnik, J. R.; Newell, D. D.

2015-08-20

This report describes the results of testing to quantify the degradation products resulting from the dilution and storage of Antifoam 747. Antifoam degradation is of concern to the Defense Waste Processing Facility (DWPF) due to flammable decomposition products in the vapor phase of the Chemical Process Cell vessels, as well as the collection of flammable and organic species in the offgas condensate. The discovery that hexamethyldisiloxane is formed from the antifoam decomposition was the basis for a Potential Inadequacy in the Safety Analysis declaration by the DWPF.

The Preparation and Characterization of INTEC HAW Phase I Composition Variation Study Glasses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Musick, C. A.; Peeler, D. K.; Piepel, G. F.

1999-03-01

A glass composition variation study (CVS) is in progress to define formulations for the vitrification of high activity waste (HAW) proposed to be separated from dissolved calcine stored at the Idaho National Engineering and Environmental Laboratory (INEEL). Estimates of calcine and HAW compositions prepared in FY97 were used to define test matrix glasses. The HAW composition is of particular interest because high aluminum, zirconium, phosphorous and potassium, and low iron and sodium content places it outside the realm of vitrification experience in the Department of Energy (DOE) complex. Through application of statistical techniques, a test matrix was defined for Phasemore » 1 of the CVS. From this matrix, formulations were systematically selected for preparation and characterization with respect to homogeneity, viscosity, liquidus temperature (TL), and leaching response when subjected to the Product Consistency Test (PCT). Based on the properties determined, certain formulations appear suitable for further development including use in planning Phase 2 of the study. It is recommended that glasses to be investigated in Phase 2 be limited to 3-5 wt % phosphate. The results of characterizing the Phase 1 glasses are presented in this document. A full analysis of the composition-property relationships of glasses being developed for immobilizing HAWs will be performing at the completion of CVS phases. This analysis will be needed for the optimization of the glass formulations of vitrifying HAW. Contributions were made to this document by personnel working at the INEEL, Pacific Northwest National Laboratories (PNNL), and the Savannah River Technology Center (SRTC).« less

Final Report - Enhanced LAW Glass Formulation Testing, VSL-07R1130-1, Rev. 0, dated 10/05/07

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, Albert A.; Pegg, I. L.; Matlack, K. S.

2013-11-13

The principal objective of this work was to extend the glass formulation methodology developed in the earlier work [2, 5, 6] for Envelope A, B and C waste compositions for development of compliant glass compositions targeting five high sodium-sulfur waste loading regions. This was accomplished through a combination of crucible-scale tests, and tests on the DM10 melter system. The DM10 was used for several previous tests on LAW compositions to determine the maximum feed sulfur concentrations that can be processed without forming secondary sulfate phases on the surface of the melt pool. This melter is the most efficient melter platformmore » for screening glass compositions over a wide range of sulfate concentrations and therefore was selected for the present tests. The tests were conducted to provide information on melter processing characteristics and off-gas data, including sulfur incorporation and partitioning. As described above, the main objective was to identify the limits of waste loading in compliant glass formulations spanning the range of expected Na{sub 2}O and SO{sub 3} concentrations in the LAW glasses.« less

DWPF Melter Off-Gas Flammability Assessment for Sludge Batch 9

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, A. S.

2016-07-11

The slurry feed to the Defense Waste Processing Facility (DWPF) melter contains several organic carbon species that decompose in the cold cap and produce flammable gases that could accumulate in the off-gas system and create potential flammability hazard. To mitigate such a hazard, DWPF has implemented a strategy to impose the Technical Safety Requirement (TSR) limits on all key operating variables affecting off-gas flammability and operate the melter within those limits using both hardwired/software interlocks and administrative controls. The operating variables that are currently being controlled include; (1) total organic carbon (TOC), (2) air purges for combustion and dilution, (3)more » melter vapor space temperature, and (4) feed rate. The safety basis limits for these operating variables are determined using two computer models, 4-stage cold cap and Melter Off-Gas (MOG) dynamics models, under the baseline upset scenario - a surge in off-gas flow due to the inherent cold cap instabilities in the slurry-fed melter.« less

HLW system plan - revision 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1994-01-14

The projected ability of the Tank Farm to support DWPF startup and continued operation has diminished somewhat since revision 1 of this Plan. The 13 month delay in DWPF startup, which actually helps the Tank Farm condition in the near term, was more than offset by the 9 month delay in ITP startup, the delay in the Evaporator startups and the reduction to Waste Removal funding. This Plan does, however, describe a viable operating strategy for the success of the HLW System and Mission, albeit with less contingency and operating flexibility than in the past. HLWM has focused resources frommore » within the division on five near term programs: The three evaporator restarts, DWPF melter heatup and completion of the ITP outage. The 1H Evaporator was restarted 12/28/93 after a 9 month shutdown for an extensive Conduct of Operations upgrade. The 2F and 2H Evaporators are scheduled to restart 3/94 and 4/94, respectively. The RHLWE startup remains 11/17/97.« less

Assessment of the Impact of a New Guanidine Suppressor In NGS on F/H Laboratory Analyses For DWPF and Saltstone MCU Transfers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C. J.

2013-04-29

Implementation of the Next Generation Solvent (NGS) in the Modular Caustic-Side Solvent Extraction Unit (MCU) will now proceed with a new suppressor compound, 1,2,3-tris(3,7-dimethyloctyl)guanidine (TiDG), replacing the originally planned suppressor for NGS, 1,3-dicyclohexyl-2-(11-methyldodecyl) guanidine (DCiTG). The Savannah River National Laboratory (SRNL) was tasked with evaluating the potential impact to F/H Laboratory analyses supporting the Defense Waste Processing Facility (DWPF) Waste Acceptance Criteria (WAC) used to qualify transfers of MCU Strip Effluent (SE) into the facility and the Saltstone WAC used to qualify transfers of Tank 50 containing Decontaminated Salt Solution (DSS) from MCU into Saltstone. This assigned scope is coveredmore » by a Task Technical and Quality Assurance Plan (TTQAP). Previous impact evaluations were conducted when the DCiTG suppressor was planned for NGS and concluded that there was no impact to either the determination of MCU SE pH nor the analysis of Isopar® L carryover in the MCU SE and DSS streams. SRNL reported on this series of cross-check studies between the SRNL and F/H Laboratories. The change in suppressor from DCiTG to TiDG in the NGS should not impact the measurement of Isopar® L or pH in SE or DSS necessary to satisfy DWPF and Saltstone WAC (Tank 50) criteria, respectively. A statistical study of the low bias observed in Isopar® L measurements in both SRNL and F/H Laboratories may be necessary now that the final NGS composition is fixed in order to quantify the low bias so that a proper correction can be applied to measurements critical to the DWPF and Saltstone WACs. Depending upon the final DWPF WAC requirement put in place for SE pH, it could become necessary to implement an alternative ICP-AES measurement of boron. The current blended solvent system testing in SRNL should address any impacts to Isopar® L carryover into either the DSS or the SE. It is recommended that SRNL monitor the current blended solvent work underway with simulants in SRNL as well as any DWPF CPC testing done with the new SE stream to ascertain whether any need develops that could result in modification of any currently planned F/H Laboratory testing protocols.« less

Glass science tutorial: Lecture No. 7, Waste glass technology for Hanford

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, A.A.

1995-07-01

This paper presents the details of the waste glass tutorial session that was held to promote knowledge of waste glass technology and how this can be used at the Hanford Reservation. Topics discussed include: glass properties; statistical approach to glass development; processing properties of nuclear waste glass; glass composition and the effects of composition on durability; model comparisons of free energy of hydration; LLW glass structure; glass crystallization; amorphous phase separation; corrosion of refractories and electrodes in waste glass melters; and glass formulation for maximum waste loading.

Aluminum in erythropoietin formulations: lyophilized versus liquid forms.

PubMed

Veiga, Marlei; Bohrer, Denise; Noremberg, Simone; Mattiazzi, Patricia; do Nascimento, Paulo C; de Carvalho, Leandro M

2013-01-01

Erythropoietin (EPO) formulations may comprise aluminum (Al) as a contaminant. Due to the toxicity of Al in chronic kidney disease patients, possible sources of Al were investigated. Since EPO formulations are stored in container-closure systems made of glass and rubber, and both contain Al, formulation ingredients may enable its leaching into the solution during shelf-life. Individual solutions of formulation ingredients were stored in new glass vials and in contact with the rubber stopper and kept at 4 ± 2 °C. For 12 months, aliquots of each solution were collected for analysis. Fifteen commercial samples of EPO were analyzed for their Al content. Aluminum was determined by atomic absorption spectrometry. Glass and rubber are sources of Al for EPO formulations. Storage assay showed that citrate and phosphate (used as buffers) extracted high amounts of Al from the container/closure parts. The most important difference, however, was found when comparing liquid and lyophilized samples. While in liquid forms the Al level reached 943 μg/L, in lyophilized forms the level did not exceed 20 μg/L. The container system was also confirmed as a source of Al in reconstituted lyophilized samples. Al in reconstituted samples stored in their own vials increased 19-fold in 12 months. Lyophilized powders stored for 2 years in glass vials contained less Al than in 1 month after dissolution. The difference in the Al measured in liquid forms of EPO and in lyophilized powders suggests that the latter would be the best pharmaceutical form for CKD patients.

Examination Of Sulfur Measurements In DWPF Sludge Slurry And SRAT Product Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C. J.; Wiedenman, B. J.

2012-11-29

Savannah River National Laboratory (SRNL) was asked to re-sample the received SB7b WAPS material for wt. % solids, perform an aqua regia digestion and analyze the digested material by inductively coupled plasma - atomic emission spectroscopy (ICP-AES), as well as re-examine the supernate by ICP-AES. The new analyses were requested in order to provide confidence that the initial analytical subsample was representative of the Tank 40 sample received and to replicate the S results obtained on the initial subsample collected. The ICP-AES analyses for S were examined with both axial and radial detection of the sulfur ICP-AES spectroscopic emission linesmore » to ascertain if there was any significant difference in the reported results. The outcome of this second subsample of the Tank 40 WAPS material is the first subject of this report. After examination of the data from the new subsample of the SB7b WAPS material, a team of DWPF and SRNL staff looked for ways to address the question of whether there was in fact insoluble S that was not being accounted for by ion chromatography (IC) analysis. The question of how much S is reaching the melter was thought best addressed by examining a DWPF Slurry Mix Evaporator (SME) Product sample, but the significant dilution of sludge material, containing the S species in question, that results from frit addition was believed to add additional uncertainty to the S analysis of SME Product material. At the time of these discussions it was believed that all S present in a Sludge Receipt and Adjustment Tank (SRAT) Receipt sample would be converted to sulfate during the course of the SRAT cycle. A SRAT Product sample would not have the S dilution effect resulting from frit addition, and hence, it was decided that a DWPF SRAT Product sample would be obtained and submitted to SRNL for digestion and sample preparation followed by a round-robin analysis of the prepared samples by the DWPF Laboratory, F/H Laboratories, and SRNL for S and sulfate. The results of this round-robin analytical study are the second subject of this report.« less

Thermal performance of glass fiber reinforced intumescent fire retardant coating for structural applications

NASA Astrophysics Data System (ADS)

Ahmad, Faiz; Ullah, Sami; Aziz, Hammad; Omar, Nor Sharifah

2015-07-01

The results of influence of glass fiber addition into the basic intumescent coating formulation towards the enhancement of its thermal insulation properties are presented. The intumescent coatings were formulated from expandable graphite, ammonium polyphosphate, melamine, boric acid, bisphenol A epoxy resin BE-188, polyamide amine H-2310 hardener and fiberglass (FG) of length 3.0 mm. Eight intumescent formulations were developed and the samples were tested for their fire performance by burning them at 450°C, 650°C and 850°C in the furnace for two hours. The effects of each fire test at different temperatures; low and high temperature were evaluated. Scanning Electron Microscope, X-Ray Diffraction technique and Thermo Gravimetric Analysis were conducted on the samples to study the morphology, the chemical components of char and the residual weight of the coatings. The formulation, FG08 containing 7.0 wt% glass fiber provided better results with enhanced thermal insulation properties of the coatings.

FY2016 Update on ILAW Glass Testing for Disposal at IDF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, E. E.; Swanberg, D. J.; Muller, Isabelle S.

2017-04-12

This status report provides a FY2016 update on work performed to collect information on the corrosion behavior of LAW glasses to support the IDF PA. In addition to the development of the baseline operating envelope for the WTP, since 2003, VSL has developed a wide range of LAW formulations that achieve considerably higher waste loadings than the WTP baseline formulations.

Defense Waste Processing Facility Simulant Chemical Processing Cell Studies for Sludge Batch 9

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Tara E.; Newell, J. David; Woodham, Wesley H.

The Savannah River National Laboratory (SRNL) received a technical task request from Defense Waste Processing Facility (DWPF) and Saltstone Engineering to perform simulant tests to support the qualification of Sludge Batch 9 (SB9) and to develop the flowsheet for SB9 in the DWPF. These efforts pertained to the DWPF Chemical Process Cell (CPC). CPC experiments were performed using SB9 simulant (SB9A) to qualify SB9 for sludge-only and coupled processing using the nitric-formic flowsheet in the DWPF. Two simulant batches were prepared, one representing SB8 Tank 40H and another representing SB9 Tank 51H. The simulant used for SB9 qualification testing wasmore » prepared by blending the SB8 Tank 40H and SB9 Tank 51H simulants. The blended simulant is referred to as SB9A. Eleven CPC experiments were run with an acid stoichiometry ranging between 105% and 145% of the Koopman minimum acid equation (KMA), which is equivalent to 109.7% and 151.5% of the Hsu minimum acid factor. Three runs were performed in the 1L laboratory scale setup, whereas the remainder were in the 4L laboratory scale setup. Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) cycles were performed on nine of the eleven. The other two were SRAT cycles only. One coupled flowsheet and one extended run were performed for SRAT and SME processing. Samples of the condensate, sludge, and off-gas were taken to monitor the chemistry of the CPC experiments.« less

Results of Hg speciation testing on DWPF SMECT-8, OGCT-1, AND OGCT-2 samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C.

2016-02-22

The Savannah River National Laboratory (SRNL) was tasked with preparing and shipping samples for Hg speciation by Eurofins Frontier Global Sciences, Inc. in Seattle, WA on behalf of the Savannah River Remediation (SRR) Mercury Task Team. The sixteenth shipment of samples was designated to include a Defense Waste Processing Facility (DWPF) Slurry Mix Evaporator Condensate Tank (SMECT) sample from Sludge Receipt and Adjustment Tank (SRAT) Batch 738 processing and two Off-Gas Condensate Tank (OGCT) samples, one following Batch 736 and one following Batch 738. The DWPF sample designations for the three samples analyzed are provided. The Batch 738 ‘End ofmore » SME Cycle’ SMECT sample was taken at the conclusion of Slurry Mix Evaporator (SME) operations for this batch and represents the fourth SMECT sample examined from Batch 738. Batch 738 experienced a sludge slurry carryover event, which introduced sludge solids to the SMECT that were particularly evident in the SMECT-5 sample, but less evident in the ‘End of SME Cycle’ SMECT-8 sample.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarrack, A.G.

The purpose of this report is to document fault tree analyses which have been completed for the Defense Waste Processing Facility (DWPF) safety analysis. Logic models for equipment failures and human error combinations that could lead to flammable gas explosions in various process tanks, or failure of critical support systems were developed for internal initiating events and for earthquakes. These fault trees provide frequency estimates for support systems failures and accidents that could lead to radioactive and hazardous chemical releases both on-site and off-site. Top event frequency results from these fault trees will be used in further APET analyses tomore » calculate accident risk associated with DWPF facility operations. This report lists and explains important underlying assumptions, provides references for failure data sources, and briefly describes the fault tree method used. Specific commitments from DWPF to provide new procedural/administrative controls or system design changes are listed in the ''Facility Commitments'' section. The purpose of the ''Assumptions'' section is to clarify the basis for fault tree modeling, and is not necessarily a list of items required to be protected by Technical Safety Requirements (TSRs).« less

Impact of Glycolate Anion on Aqueous Corrosion in DWPF and Downstream Facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mickalonis, J.

Glycolic acid is being evaluated as an alternate reductant in the preparation of high level waste for the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS). During processing, the glycolic acid may not be completely consumed with small quantities of the glycolate anion being carried forward to other high level waste (HLW) facilities. The SRS liquid waste contractor requested an assessment of the impact of the glycolate anion on the corrosion of the materials of construction (MoC) throughout the waste processing system since this impact had not been previously evaluated. A literature review revealed that corrosion datamore » were not available for the MoCs in glycolic-bearing solutions applicable to SRS systems. Data on the material compatibility with only glycolic acid or its derivative products were identified; however, data were limited for solutions containing glycolic acid or the glycolate anion. For the proprietary coating systems applied to the DWPF concrete, glycolic acid was deemed compatible since the coatings were resistant to more aggressive chemistries than glycolic acid. Additionally, similar coating resins showed acceptable resistance to glycolic acid.« less

Impact of Glycolate Anion on Aqueous Corrosion in DWPF and Downstream Facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mickalonis, J.

Glycolic acid is being evaluated as an alternate reductant in the preparation of high level waste for the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS). During processing, the glycolic acid may not be completely consumed with small quantities of the glycolate anion being carried forward to other high level waste (HLW) facilities. The SRS liquid waste contractor requested an assessment of the impact of the glycolate anion on the corrosion of the materials of construction (MoC) throughout the waste processing system since this impact had not been previously evaluated. A literature review revealed that corrosion datamore » were not available for the MoCs in glycolic-bearing solutions applicable to SRS systems. Data on the material compatibility with only glycolic acid or its derivative products were identified; however, data were limited for solutions containing glycolic acid or the glycolate anion. For the proprietary coating systems applied to the DWPF concrete, glycolic acid was deemed compatible since the coatings were resistant to more aggressive chemistries than glycolic acid. Additionally similar coating resins showed acceptable resistance to glycolic acid.« less

2013 CEF RUN - PHASE 1 DATA ANALYSIS AND MODEL VALIDATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, A.

2014-05-08

Phase 1 of the 2013 Cold cap Evaluation Furnace (CEF) test was completed on June 3, 2013 after a 5-day round-the-clock feeding and pouring operation. The main goal of the test was to characterize the CEF off-gas produced from a nitric-formic acid flowsheet feed and confirm whether the CEF platform is capable of producing scalable off-gas data necessary for the revision of the DWPF melter off-gas flammability model; the revised model will be used to define new safety controls on the key operating parameters for the nitric-glycolic acid flowsheet feeds including total organic carbon (TOC). Whether the CEF off-gas datamore » were scalable for the purpose of predicting the potential flammability of the DWPF melter exhaust was determined by comparing the predicted H{sub 2} and CO concentrations using the current DWPF melter off-gas flammability model to those measured during Phase 1; data were deemed scalable if the calculated fractional conversions of TOC-to-H{sub 2} and TOC-to-CO at varying melter vapor space temperatures were found to trend and further bound the respective measured data with some margin of safety. Being scalable thus means that for a given feed chemistry the instantaneous flow rates of H{sub 2} and CO in the DWPF melter exhaust can be estimated with some degree of conservatism by multiplying those of the respective gases from a pilot-scale melter by the feed rate ratio. This report documents the results of the Phase 1 data analysis and the necessary calculations performed to determine the scalability of the CEF off-gas data. A total of six steady state runs were made during Phase 1 under non-bubbled conditions by varying the CEF vapor space temperature from near 700 to below 300°C, as measured in a thermowell (T{sub tw}). At each steady state temperature, the off-gas composition was monitored continuously for two hours using MS, GC, and FTIR in order to track mainly H{sub 2}, CO, CO{sub 2}, NO{sub x}, and organic gases such as CH{sub 4}. The standard deviation of the average vapor space temperature during each steady state ranged from 2 to 6°C; however, those of the measured off-gas data were much larger due to the inherent cold cap instabilities in the slurry-fed melters. In order to predict the off-gas composition at the sampling location downstream of the film cooler, the measured feed composition was charge-reconciled and input into the DWPF melter off-gas flammability model, which was then run under the conditions for each of the six Phase 1 steady states. In doing so, it was necessary to perform an overall heat/mass balance calculation from the melter to the Off-Gas Condensate Tank (OGCT) in order to estimate the rate of air inleakage as well as the true gas temperature in the CEF vapor space (T{sub gas}) during each steady state by taking into account the effects of thermal radiation on the measured temperature (T{sub tw}). The results of Phase 1 data analysis and subsequent model runs showed that the predicted concentrations of H{sub 2} and CO by the DWPF model correctly trended and further bounded the respective measured data in the CEF off-gas by over predicting the TOC-to-H{sub 2} and TOC-to-CO conversion ratios by a factor of 2 to 5; an exception was the 7X over prediction of the latter at T{sub gas} = 371°C but the impact of CO on the off-gas flammability potential is only minor compared to that of H{sub 2}. More importantly, the seemingly-excessive over prediction of the TOC-to-H{sub 2} conversion by a factor of 4 or higher at T{sub gas} < ~350°C was attributed to the conservative antifoam decomposition scheme added recently to the model and therefore is considered a modeling issue and not a design issue. At T{sub gas} > ~350°C, the predicted TOC-to-H{sub 2} conversions were closer to but still higher than the measured data by a factor of 2, which may be regarded as adequate from the safety margin standpoint. The heat/mass balance calculations also showed that the correlation between T{sub tw} and T{sub gas} in the CEF vapor space was close to that of the ½ scale SGM, whose data were taken as directly applicable to the DWPF melter and thus used to set all the parameters of the original model. Based on these results of the CEF Phase 1 off-gas and thermal data analyses, it is concluded that: (1) The thermal characteristics of the CEF vapor space are prototypic thanks to its prototypic design; and (2) The CEF off-gas data are scalable in terms of predicting the flammability potential of the DWPF melter off-gas. These results also show that the existing DWPF safety controls on the TOC and antifoam as a function of nitrate are conservative by the same order of magnitude shown by the Phase 1 data at T{sub gas} < ~350°C, since they were set at T{sub gas} = 294°C, which falls into the region of excessive conservatism for the current DWPF model in terms of predicting the TOC-to-H{sub 2} conversion. In order to remedy the overly-conservative antifoam decomposition scheme used in the current DWPF model, the data from two recent tests will be analyzed in detail in order to gain additional insights into the antifoam decomposition chemistry in the cold cap. The first test was run in a temperature-programmed furnace using both normal and spiked feeds with fresh antifoam under inert and slightly oxidizing vapor space conditions. Phase 2 of the CEF test was run with the baseline nitric-glycolic acid flowsheet feeds that contained the “processed antifoam” and those spiked with fresh antifoam in order to study the effects of antifoam concentration as well as processing history on its decomposition chemistry under actual melter conditions. The goal is to develop an improved antifoam decomposition model from the analysis of these test data and incorporate it into a new multistage cold cap model to be developed concurrently for the nitric-glycolic acid flowsheet feeds. These activities will be documented in the Phase 2 report. Finally, it is recommended that some of the conservatism in the existing DWPF safety controls be removed by improving the existing measured-vs.-true gas temperature correlation used in the melter vapor space combustion calculations. The basis for this recommendation comes from the fact that the existing correlation was developed by linearly extrapolating the SGM data taken over a relatively narrow temperature range down to the safety basis minimum of 460°C, thereby under predicting the true gas temperature considerably, as documented in this report. Specifically, the task of improving the current temperature correlation will involve; (1) performing a similar heat/mass balance analysis used in this study on actual DWPF data, (2) validating the measured-vs.-true gas temperature correlation for the CEF developed in this study against the DWPF melter heat/mass balance results, and (3) making adjustments to the CEF correlation, if necessary, before incorporating it into the DWPF safety basis calculations. The steps described here can be completed with relatively minimum efforts.« less

Glass/Ceramic Composites for Sealing Solid Oxide Fuel Cells

NASA Technical Reports Server (NTRS)

Bansal, Narottam P.; Choi, Sung R.

2007-01-01

A family of glass/ceramic composite materials has been investigated for use as sealants in planar solid oxide fuel cells. These materials are modified versions of a barium calcium aluminosilicate glass developed previously for the same purpose. The composition of the glass in mole percentages is 35BaO + 15CaO + 5Al2O3 + 10B2O3 + 35SiO2. The glass seal was found to be susceptible to cracking during thermal cycling of the fuel cells. The goal in formulating the glass/ ceramic composite materials was to (1) retain the physical and chemical advantages that led to the prior selection of the barium calcium aluminosilicate glass as the sealant while (2) increasing strength and fracture toughness so as to reduce the tendency toward cracking. Each of the composite formulations consists of the glass plus either of two ceramic reinforcements in a proportion between 0 and 30 mole percent. One of the ceramic reinforcements consists of alumina platelets; the other one consists of particles of yttria-stabilized zirconia wherein the yttria content is 3 mole percent (3YSZ). In preparation for experiments, panels of the glass/ceramic composites were hot-pressed and machined into test bars.

Defense Waste Processing Facility Nitric- Glycolic Flowsheet Chemical Process Cell Chemistry: Part 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zamecnik, J.; Edwards, T.

The conversions of nitrite to nitrate, the destruction of glycolate, and the conversion of glycolate to formate and oxalate were modeled for the Nitric-Glycolic flowsheet using data from Chemical Process Cell (CPC) simulant runs conducted by Savannah River National Laboratory (SRNL) from 2011 to 2016. The goal of this work was to develop empirical correlation models to predict these values from measureable variables from the chemical process so that these quantities could be predicted a-priori from the sludge or simulant composition and measurable processing variables. The need for these predictions arises from the need to predict the REDuction/OXidation (REDOX) statemore » of the glass from the Defense Waste Processing Facility (DWPF) melter. This report summarizes the work on these correlations based on the aforementioned data. Previous work on these correlations was documented in a technical report covering data from 2011-2015. This current report supersedes this previous report. Further refinement of the models as additional data are collected is recommended.« less

Modified EVA Encapsulant Formulations for Low Temperature Processing: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mei, Z.; Pern, F. J.; Glick, S. H.

2001-10-01

Presented at the 2001 NCPV Program Review Meeting: We have developed several new ethylene-vinyl acetate (EVA) formulations modified on the basis of NREL patented EVA formulations [1]. The new formulations can be cured to a desired gel content of {approx}80% in the ambient at temperatures 20-30 C lower than the typical conditions in vacuum (i.e. {approx}150 C). Glass/glass laminates showed transmittance spectra that are essentially the same as that of EVA 15295P in the visible and NIR regions but higher in the UV region. Results of fluorescence analysis of the ambient-processed new EVA formulations showed the concentrations of the curing-generatedmore » {alpha},{beta}-unsaturated carbonyl chromophores, which are responsible for the UV induced EVA discoloration and photodegradation, were considerably lower than that of EVA 15295P, therefore suggesting a better photochemical stability of new EVA formulations.« less

Modeling and simulation of large scale stirred tank

NASA Astrophysics Data System (ADS)

Neuville, John R.

The purpose of this dissertation is to provide a written record of the evaluation performed on the DWPF mixing process by the construction of numerical models that resemble the geometry of this process. There were seven numerical models constructed to evaluate the DWPF mixing process and four pilot plants. The models were developed with Fluent software and the results from these models were used to evaluate the structure of the flow field and the power demand of the agitator. The results from the numerical models were compared with empirical data collected from these pilot plants that had been operated at an earlier date. Mixing is commonly used in a variety ways throughout industry to blend miscible liquids, disperse gas through liquid, form emulsions, promote heat transfer and, suspend solid particles. The DOE Sites at Hanford in Richland Washington, West Valley in New York, and Savannah River Site in Aiken South Carolina have developed a process that immobilizes highly radioactive liquid waste. The radioactive liquid waste at DWPF is an opaque sludge that is mixed in a stirred tank with glass frit particles and water to form slurry of specified proportions. The DWPF mixing process is composed of a flat bottom cylindrical mixing vessel with a centrally located helical coil, and agitator. The helical coil is used to heat and cool the contents of the tank and can improve flow circulation. The agitator shaft has two impellers; a radial blade and a hydrofoil blade. The hydrofoil is used to circulate the mixture between the top region and bottom region of the tank. The radial blade sweeps the bottom of the tank and pushes the fluid in the outward radial direction. The full scale vessel contains about 9500 gallons of slurry with flow behavior characterized as a Bingham Plastic. Particles in the mixture have an abrasive characteristic that cause excessive erosion to internal vessel components at higher impeller speeds. The desire for this mixing process is to ensure the agitation of the vessel is adequate to produce a homogenous mixture but not so high that it produces excessive erosion to internal components. The main findings reported by this study were: (1) Careful consideration of the fluid yield stress characteristic is required to make predictions of fluid flow behavior. Laminar Models can predict flow patterns and stagnant regions in the tank until full movement of the flow field occurs. Power Curves and flow patterns were developed for the full scale mixing model to show the differences in expected performance of the mixing process for a broad range of fluids that exhibit Herschel--Bulkley and Bingham Plastic flow behavior. (2) The impeller power demand is independent of the flow model selection for turbulent flow fields in the region of the impeller. The laminar models slightly over predicted the agitator impeller power demand produced by turbulent models. (3) The CFD results show that the power number produced by the mixing system is independent of size. The 40 gallon model produced the same power number results as the 9300 gallon model for the same process conditions. (4) CFD Results show that the Scale-Up of fluid motion in a 40 gallon tank should compare with fluid motion at full scale, 9300 gallons by maintaining constant impeller Tip Speed.

SLUDGE BATCH 4 BASELINE MELT RATE FURNACE AND SLURRY-FED MELT RATE FURNACE TESTS WITH FRITS 418 AND 510 (U)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, M. E.; Jones, T. M.; Miller, D. H.

Several Slurry-Fed Melt Rate Furnace (SMRF) tests with earlier projections of the Sludge Batch 4 (SB4) composition have been performed.1,2 The first SB4 SMRF test used Frits 418 and 320, however it was found after the test that the REDuction/OXidation (REDOX) correlation at that time did not have the proper oxidation state for manganese. Because the manganese level in the SB4 sludge was higher than previous sludge batches tested, the impact of the higher manganese oxidation state was greater. The glasses were highly oxidized and very foamy, and therefore the results were inconclusive. After resolving this REDOX issue, Frits 418,more » 425, and 503 were tested in the SMRF with the updated baseline SB4 projection. Based on dry-fed Melt Rate Furnace (MRF) tests and the above mentioned SMRF tests, two previous frit recommendations were made by the Savannah River National Laboratory (SRNL) for processing of SB4 in the Defense Waste Processing Facility (DWPF). The first was Frit 503 based on the June 2006 composition projections.3 The recommendation was changed to Frit 418 as a result of the October 2006 composition projections (after the Tank 40 decant was implemented as part of the preparation plan). However, the start of SB4 processing was delayed due to the control room consolidation outage and the repair of the valve box in the Tank 51 to Tank 40 transfer line. These delays resulted in changes to the projected SB4 composition. Due to the slight change in composition and based on preliminary dry-fed MRF testing, SRNL believed that Frit 510 would increase throughput in processing SB4 in DWPF. Frit 418, which was used in processing Sludge Batch 3 (SB3), was a viable candidate and available in DWPF. Therefore, it was used during the initial SB4 processing. Due to the potential for higher melt rates with Frit 510, SMRF tests with the latest SB4 composition (1298 canisters) and Frits 510 and 418 were performed at a targeted waste loading (WL) of 35%. The '1298 canisters' describes the number of equivalent canisters that would be produced from the beginning of the current contract period before SB3 is blended with SB4. The melt rate for the SMRF SB4/Frit 510 test was 14.6 grams/minute. Due to cold cap mounding problems with the SMRF SB4/Frit 418 feed at 50 weight % solids that prevented a melt rate determination, this feed was diluted to 45 weight % solids. The melt rate for this diluted feed was 8.9 grams/minute. A correction factor of 1.2 for estimating the melt rate at 50 weight % solids from 45 weight % solids test results (based on previous SMRF testing5) was then used to estimate a melt rate of 10.7 grams/minute for SB4/Frit 418 at 50 weight % solids. Therefore, the use of Frit 510 versus Frit 418 with SB4 resulted in a higher melt rate (14.6 versus an estimated 10.7 grams/minute). For reference, a previous SMRF test with SB3/Frit 418 feed at 35% waste loading and 50 weight % solids resulted in a melt rate of 14.1 grams/minute. Therefore, depending on the actual feed rheology, the use of Frit 510 with SB4 could result in similar melt rates as experienced with SB3/Frit 418 feed in the DWPF.« less

Winter Severe Weather: A Case Study of the Intense Squall Line of 6-7 January 1995 in the Carolinas

DTIC Science & Technology

1996-01-01

line. 51 U- U- )C nM-,L Cz2r r Zr’.r - -52 cz bi2 0z CPIu Inu leu bts 533 rMPF DWPF 39 36- 30------- - - - - - - - - - - - - PMiL 014- Gusr DARR 10- 6...14u cz lo0 Go0 Go a- Nr, lou 58 ,t, 7!Ch 59 Lr, CC 7 ~ cr cz 60 z u-, II Zn zc z 11 L1X - CL Aar- c- 61 100 CCu ac- Go 62 mm IflIN Z N _ m 63 TMPF DWPF

Incorporation de particules de verre post-consommation dans un enrobe bitumineux de type ESG14

NASA Astrophysics Data System (ADS)

Lachance Tremblay, Eric

In 2008, around 244,000 tons of glass was produced by the Quebec population. From this number, 128,000 tons were collected by various means of collection. Glass recycling is problematic because all the glass that cannot be classified according to the type can't be used to manufacture new products. It is therefore necessary to find new sources of uses for this material. Because the use of recycled materials in road structure material is beneficial from an environmental and sometimes structural point of view, the idea of using recycled glass into asphalt mixture was recently studied at the LCMB. Nowadays, the use of recycled glass in asphalt mixture is not regulated by the MTQ. This research goal was to verify the possibility of using recycled glass particles in a ESG14 asphalt mixture while maintaining equivalent properties and performance compared to a conventional mix. Different dosages of recycled glass particles have been studied to evaluate the effect of glass on the asphalt mixture volumetric characteristics, the ability of compaction and the rutting resistance. These mixes were formulated according to the LC formulation of the MTQ. The first part allowed selecting an optimal dosage of recycled glass particles. Thereafter, the thermo mechanical performance (resistance to low temperatures (TSRST), complex modulus (E*) and resistance to fatigue cracking), physical characteristics (macro texture and surface grip) and durability (resistance to water damage) of the asphalt mixture with the optimal dosage were evaluated and compared with a reference mixture. The results show that the ESG14 mixture with recycled glass formulated with the LC method is more susceptible to rutting than the reference mixture. Therefore, a reduction of the bitumen content can increase the rutting resistance while conserving equivalent properties to a conventional mix regarding resistance to low temperatures, complex modulus, resistance to fatigue cracking as well as the physical characteristics. Therefore, the use of recycled in glass seems to modify the asphalt behavior and increase the moisture susceptibility.

Bioactive Glasses with Low Ca/P Ratio and Enhanced Bioactivity

PubMed Central

Araújo, Marco; Miola, Marta; Baldi, Giovanni; Perez, Javier; Verné, Enrica

2016-01-01

Three new silica-based glass formulations with low molar Ca/P ratio (2–3) have been synthesized. The thermal properties, the crystalline phases induced by thermal treatments and the sintering ability of each glass formulation have been investigated by simultaneous differential scanning calorimetry-thermogravimetric analysis (DSC-TG), X-ray diffraction (XRD) and hot stage microscopy (HSM). The glasses exhibited a good sintering behavior, with two samples achieving shrinkage of 85%–95% prior to crystallization. The bioactivity of the glasses in simulated body fluid (SBF) has been investigated by performing XRD and Fourier transform infrared spectroscopy (FTIR) on the samples prior and after immersion. The glasses with lower MgO contents were able to form a fully crystallized apatite layer after three days of immersion in simulated body fluid (SBF), while for the glass exhibiting a higher MgO content in its composition, the crystallization of the Ca–P layer was achieved after seven days. The conjugation of these properties opens new insights on the synthesis of highly bioactive and mechanically strong prosthetic materials. PMID:28773350

In vivo bone tissue response to a canasite glass-ceramic.

PubMed

da Rocha Barros, V M; Salata, L A; Sverzut, C E; Xavier, S P; van Noort, R; Johnson, A; Hatton, P V

2002-07-01

The aim of this study was to determine the biocompatibility and osteoconductive potential of a high-strength canasite glass ceramic. Glass-ceramic rods were produced using the lost-wax casting technique and implanted in the mid-shafts rabbit femurs. Implants were harvested at 4, 13 and 22 weeks and prepared for light and electron microscopy. Hydroxyapatite was used as a control material. Hydroxyapatite implants were surrounded by new mineralised bone tissue after 4 weeks of implantation. The amount of bone surrounding the implant increased slightly at 13 weeks. In contrast, canasite glass and glass ceramic implants were almost entirely surrounded by soft tissue during all the time periods. Close contact between bone and canasite glass-ceramic implant without the intervening fibrous tissue was observed in only a few regions. The canasite formulation evaluated was not osteoconductive and appeared to degrade in the biological environment. It was therefore concluded that the canasite formulation used was unsuitable for use as implant. Further work is required to improve the biocompatibility of these materials with bone tissue. It is possible that this could be achieved by reducing the solubility of the glass and glass ceramic.

DWPF Recycle Evaporator Simulant Tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, M

2005-04-05

Testing was performed to determine the feasibility and processing characteristics of an evaporation process to reduce the volume of the recycle stream from the Defense Waste Processing Facility (DWPF). The concentrated recycle would be returned to DWPF while the overhead condensate would be transferred to the Effluent Treatment Plant. Various blends of evaporator feed were tested using simulants developed from characterization of actual recycle streams from DWPF and input from DWPF-Engineering. The simulated feed was evaporated in laboratory scale apparatus to target a 30X volume reduction. Condensate and concentrate samples from each run were analyzed and the process characteristics (foaming,more » scaling, etc) were visually monitored during each run. The following conclusions were made from the testing: Concentration of the ''typical'' recycle stream in DWPF by 30X was feasible. The addition of DWTT recycle streams to the typical recycle stream raises the solids content of the evaporator feed considerably and lowers the amount of concentration that can be achieved. Foaming was noted during all evaporation tests and must be addressed prior to operation of the full-scale evaporator. Tests were conducted that identified Dow Corning 2210 as an antifoam candidate that warrants further evaluation. The condensate has the potential to exceed the ETP WAC for mercury, silicon, and TOC. Controlling the amount of equipment decontamination recycle in the evaporator blend would help meet the TOC limits. The evaporator condensate will be saturated with mercury and elemental mercury will collect in the evaporator condensate collection vessel. No scaling on heating surfaces was noted during the tests, but splatter onto the walls of the evaporation vessels led to a buildup of solids. These solids were difficult to remove with 2M nitric acid. Precipitation of solids was not noted during the testing. Some of the aluminum present in the recycle streams was converted from gibbsite to aluminum oxide during the evaporation process. The following recommendations were made: Recycle from the DWTT should be metered in slowly to the ''typical'' recycle streams to avoid spikes in solids content to allow consistent processing and avoid process upsets. Additional studies should be conducted to determine acceptable volume ratios for the HEME dissolution and decontamination solutions in the evaporator feed. Dow Corning 2210 antifoam should be evaluated for use to control foaming. Additional tests are required to determine the concentration of antifoam required to prevent foaming during startup, the frequency of antifoam additions required to control foaming during steady state processing, and the ability of the antifoam to control foam over a range of potential feed compositions. This evaluation should also include evaluation of the degradation of the antifoam and impact on the silicon and TOC content of the condensate. The caustic HEME dissolution recycle stream should be neutralized to at least pH of 7 prior to blending with the acidic recycle streams. Dow Corning 2210 should be used during the evaporation testing using the radioactive recycle samples received from DWPF. Evaluation of additional antifoam candidates should be conducted as a backup for Dow Corning 2210. A camera and/or foam detection instrument should be included in the evaporator design to allow monitoring of the foaming behavior during operation. The potential for foam formation and high solids content should be considered during the design of the evaporator vessel.« less

Consistency of the free-volume approach to the homogeneous deformation of metallic glasses

NASA Astrophysics Data System (ADS)

Blétry, Marc; Thai, Minh Thanh; Champion, Yannick; Perrière, Loïc; Ochin, Patrick

2014-05-01

One of the most widely used approaches to model metallic-glasses high-temperature homogeneous deformation is the free-volume theory, developed by Cohen and Turnbull and extended by Spaepen. A simple elastoviscoplastic formulation has been proposed that allows one to determine various parameters of such a model. This approach is applied here to the results obtained by de Hey et al. on a Pd-based metallic glass. In their study, de Hey et al. were able to determine some of the parameters used in the elastoviscoplastic formulation through DSC modeling coupled with mechanical tests, and the consistency of the two viewpoints was assessed.

EFFECTS OF ONE WEEK TRITIUM EXPOSURE ON EPDM ELASTOMER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, E

This report documents test results for the exposure of four formulations of EPDM (ethylene-propylene diene monomer) elastomer to tritium gas at one atmosphere for approximately one week and characterization of material property changes and changes to the exposure gas during exposure. All EPDM samples were provided by Los Alamos National Laboratory (LANL). Material properties that were characterized include mass, sample dimensions, appearance, flexibility, and dynamic mechanical properties. The glass transition temperature was determined by analysis of the dynamic mechanical property data per ASTM standards. No change of glass transition temperature due to the short tritium gas exposure was observed. Filledmore » and unfilled formulations of Dupont{reg_sign} Nordel{trademark} 1440 had a slightly higher glass transition temperature than filled and unfilled formulations of Uniroyal{reg_sign} Royalene{reg_sign} 580H; filled formulations had the same glass transition as unfilled. The exposed samples appeared the same as before exposure--there was no evidence of discoloration, and no residue on stainless steel spacers contacting the samples during exposure was observed. The exposed samples remained flexible--all formulations passed a break test without failing. The unique properties of polymers make them ideal for certain components in gas handling systems. Specifically, the resiliency of elastomers is ideal for sealing surfaces, for example in valves. EPDM, initially developed in the 1960s, is a hydrocarbon polymer used extensively for sealing applications. EPDM is used for its excellent combination of properties including high/low-temperature resistance, radiation resistance, aging resistance, and good mechanical properties. This report summarizes initial work to characterize effects of tritium gas exposure on samples of four types of EPDM elastomer: graphite filled and unfilled formulations of Nordel{trademark} 1440 and Royalene{reg_sign} 580H.« less

Assessment of the impact of the next generation solvent on DWPF melter off-gas flammability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daniel, W. E.

2013-02-13

An assessment has been made to evaluate the impact on the DWPF melter off-gas flammability of replacing the current solvent used in the Modular Caustic-Side Solvent Extraction Process Unit (MCU) process with the Next Generation Solvent (NGS-MCU) and blended solvent. The results of this study showed that the concentrations of nonvolatile carbon and hydrogen of the current solvent in the Slurry Mix Evaporator (SME) product would both be about 29% higher than their counterparts of the NGS-MCU and blended solvent in the absence of guanidine partitioning. When 6 ppm of guanidine (TiDG) was added to the effluent transfer to DWPFmore » to simulate partitioning for the NGS-MCU and blended solvent cases and the concentration of Isopar{reg_sign} L in the effluent transfer was controlled below 87 ppm, the concentrations of nonvolatile carbon and hydrogen of the NGS-MCU and blended solvent were still about 12% and 4% lower, respectively, than those of the current solvent. It is, therefore, concluded that as long as the volume of MCU effluent transfer to DWPF is limited to 15,000 gallons per Sludge Receipt and Adjustment Tank (SRAT)/SME cycle and the concentration of Isopar{reg_sign} L in the effluent transfer is controlled below 87 ppm, using the current solvent assumption of 105 ppm Isopar{reg_sign} L or 150 ppm solvent in lieu of NGS-MCU or blended solvent in the DWPF melter off-gas flammability assessment is conservative for up to an additional 6 ppm of TiDG in the effluent due to guanidine partitioning. This report documents the calculations performed to reach this conclusion.« less

Enhanced Adhesion of EVA Laminates to Primed Glass Substrates Subjected to Damp-Heat Exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pern, F. J.; Jorgensen, G. J.

2005-02-01

We investigated the effectiveness of glass-surface priming to promote enhanced adhesion of EVA laminates during damp-heat exposure at 85 C and 85% relative humidity. The primary objective was to develop advanced encapsulant formulations by incorporation of various primer formulations that exhibit improved adhesion during damp-heat exposure. Several primer formulations were identified that greatly enhanced the EVA adhesion strength, including to the extent that peeling could not be initiated, even for the laminates of the glass substrate/fast-cure EVA15295P/TPE backsheet (a Tedlar/polyester/EVA tri-laminate) that were exposed in a damp-heat test chamber for more than 750 h. The results show that a synergisticmore » increase in the interfacial hydrophobicity, siloxane density, and cross-linking density are the key attributes to the improvement in the EVA adhesion strength.« less

Advances in Glass Formulations for Hanford High-Aluminum, High-Iron and Enhanced Sulphate Management in HLW Streams - 13000

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, Albert A.

2013-07-01

The current estimates and glass formulation efforts have been conservative in terms of achievable waste loadings. These formulations have been specified to ensure that the glasses are homogenous, contain essentially no crystalline phases, are processable in joule-heated, ceramic-lined melters and meet Hanford Tank Waste Treatment and Immobilization Plant (WTP) Contract terms. The WTP's overall mission will require the immobilization of tank waste compositions that are dominated by mixtures of aluminum (Al), chromium (Cr), bismuth (Bi), iron (Fe), phosphorous (P), zirconium (Zr), and sulphur (S) compounds as waste-limiting components. Glass compositions for these waste mixtures have been developed based upon previousmore » experience and current glass property models. Recently, DOE has initiated a testing program to develop and characterize HLW glasses with higher waste loadings and higher throughput efficiencies. Results of this work have demonstrated the feasibility of increases in waste loading from about 25 wt% to 33-50 wt% (based on oxide loading) in the glass depending on the waste stream. In view of the importance of aluminum limited waste streams at Hanford (and also Savannah River), the ability to achieve high waste loadings without adversely impacting melt rates has the potential for enormous cost savings from reductions in canister count and the potential for schedule acceleration. Consequently, the potential return on the investment made in the development of these enhancements is extremely favorable. Glass composition development for one of the latest Hanford HLW projected compositions with sulphate concentrations high enough to limit waste loading have been successfully tested and show tolerance for previously unreported tolerance for sulphate. Though a significant increase in waste loading for high-iron wastes has been achieved, the magnitude of the increase is not as substantial as those achieved for high-aluminum, high-chromium, high-bismuth or sulphur. Waste processing rate increases for high-iron streams as a combined effect of higher waste loadings and higher melt rates resulting from new formulations have been achieved. (author)« less

Advances in Glass Formulations for Hanford High-Alumimum, High-Iron and Enhanced Sulphate Management in HLW Streams - 13000

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, Albert A.

2013-01-16

The current estimates and glass formulation efforts have been conservative in terms of achievable waste loadings. These formulations have been specified to ensure that the glasses are homogenous, contain essentially no crystalline phases, are processable in joule-heated, ceramic-lined melters and meet Hanford Tank Waste Treatment and Immobilization Plant (WTP) Contract terms. The WTP?s overall mission will require the immobilization of tank waste compositions that are dominated by mixtures of aluminum (Al), chromium (Cr), bismuth (Bi), iron (Fe), phosphorous (P), zirconium (Zr), and sulphur (S) compounds as waste-limiting components. Glass compositions for these waste mixtures have been developed based upon previousmore » experience and current glass property models. Recently, DOE has initiated a testing program to develop and characterize HLW glasses with higher waste loadings and higher throughput efficiencies. Results of this work have demonstrated the feasibility of increases in waste loading from about 25 wt% to 33-50 wt% (based on oxide loading) in the glass depending on the waste stream. In view of the importance of aluminum limited waste streams at Hanford (and also Savannah River), the ability to achieve high waste loadings without adversely impacting melt rates has the potential for enormous cost savings from reductions in canister count and the potential for schedule acceleration. Consequently, the potential return on the investment made in the development of these enhancements is extremely favorable. Glass composition development for one of the latest Hanford HLW projected compositions with sulphate concentrations high enough to limit waste loading have been successfully tested and show tolerance for previously unreported tolerance for sulphate. Though a significant increase in waste loading for high-iron wastes has been achieved, the magnitude of the increase is not as substantial as those achieved for high-aluminum, high-chromium, high-bismuth or sulphur. Waste processing rate increases for high-iron streams as a combined effect of higher waste loadings and higher melt rates resulting from new formulations have been achieved.« less

Recycling of inorganic waste in monolithic and cellular glass‐based materials for structural and functional applications

PubMed Central

Rincón, Acacio; Marangoni, Mauro; Cetin, Suna

2016-01-01

Abstract The stabilization of inorganic waste of various nature and origin, in glasses, has been a key strategy for environmental protection for the last decades. When properly formulated, glasses may retain many inorganic contaminants permanently, but it must be acknowledged that some criticism remains, mainly concerning costs and energy use. As a consequence, the sustainability of vitrification largely relies on the conversion of waste glasses into new, usable and marketable glass‐based materials, in the form of monolithic and cellular glass‐ceramics. The effective conversion in turn depends on the simultaneous control of both starting materials and manufacturing processes. While silica‐rich waste favours the obtainment of glass, iron‐rich wastes affect the functionalities, influencing the porosity in cellular glass‐based materials as well as catalytic, magnetic, optical and electrical properties. Engineered formulations may lead to important reductions of processing times and temperatures, in the transformation of waste‐derived glasses into glass‐ceramics, or even bring interesting shortcuts. Direct sintering of wastes, combined with recycled glasses, as an example, has been proven as a valid low‐cost alternative for glass‐ceramic manufacturing, for wastes with limited hazardousness. The present paper is aimed at providing an up‐to‐date overview of the correlation between formulations, manufacturing technologies and properties of most recent waste‐derived, glass‐based materials. © 2016 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:27818564

ISOLOK VALVE ACCEPTANCE TESTING FOR DWPF SME SAMPLING PROCESS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, T.; Hera, K.; Coleman, C.

2011-12-05

Evaluation of the Defense Waste Processing Facility (DWPF) Chemical Process Cell (CPC) cycle time identified several opportunities to improve the CPC processing time. Of the opportunities, a focus area related to optimizing the equipment and efficiency of the sample turnaround time for DWPF Analytical Laboratory was identified. The Mechanical Systems & Custom Equipment Development (MS&CED) Section of the Savannah River National Laboratory (SRNL) evaluated the possibility of using an Isolok{reg_sign} sampling valve as an alternative to the Hydragard{reg_sign} valve for taking process samples. Previous viability testing was conducted with favorable results using the Isolok sampler and reported in SRNL-STI-2010-00749 (1).more » This task has the potential to improve operability, reduce maintenance time and decrease CPC cycle time. This report summarizes the results from acceptance testing which was requested in Task Technical Request (TTR) HLW-DWPF-TTR-2010-0036 (2) and which was conducted as outlined in Task Technical and Quality Assurance Plan (TTQAP) SRNL-RP-2011-00145 (3). The Isolok to be tested is the same model which was tested, qualified, and installed in the Sludge Receipt Adjustment Tank (SRAT) sample system. RW-0333P QA requirements apply to this task. This task was to qualify the Isolok sampler for use in the DWPF Slurry Mix Evaporator (SME) sampling process. The Hydragard, which is the current baseline sampling method, was used for comparison to the Isolok sampling data. The Isolok sampler is an air powered grab sampler used to 'pull' a sample volume from a process line. The operation of the sampler is shown in Figure 1. The image on the left shows the Isolok's spool extended into the process line and the image on the right shows the sampler retracted and then dispensing the liquid into the sampling container. To determine tank homogeneity, a Coliwasa sampler was used to grab samples at a high and low location within the mixing tank. Data from the two locations were compared to determine if the contents of the tank were well mixed. The Coliwasa sampler is a tube with a stopper at the bottom and is designed to obtain grab samples from specific locations within the drum contents. A position paper (4) was issued to address the prototypic flow loop issues and simulant selections. A statistically designed plan (5) was issued to address the total number of samples each sampler needed to pull, to provide the random order in which samples were pulled and to group samples for elemental analysis. The TTR required that the Isolok sampler perform as well as the Hydragard sampler during these tests to ensure the acceptability of the Isolok sampler for use in the DWPF sampling cells. Procedure No.L9.4-5015 was used to document the sample parameters and process steps. Completed procedures are located in R&D Engineering job folder 23269.« less

The In Vitro Bioactivity, Degradation, and Cytotoxicity of Polymer-Derived Wollastonite-Diopside Glass-Ceramics

PubMed Central

Juraski, Amanda De Castro; Dorion Rodas, Andrea Cecilia; Elsayed, Hamada; Bernardo, Enrico; Oliveira Soares, Viviane; Daguano, Juliana

2017-01-01

Ca-Mg silicates are receiving a growing interest in the field of bioceramics. In a previous study, wollastonite-diopside (WD) glass-ceramics were successfully prepared by a new processing route, consisting of the heat treatment of a silicone resin embedding reactive oxide particles and a Ca/Mg-rich glass. The in vitro degradation, bioactivity, and cell response of these new WD glass-ceramics, fired at 900–1100 °C for 1 h, as a function of the Ca/Mg-rich glass content, are the aim of this investigation The results showed that WD glass-ceramics from formulations comprising different glass contents (70–100% at 900 °C, 30% at 1100 °C) exhibit the formation of an apatite-like layer on their surface after immersion in SBF for seven days, thus confirming their surface bioactivity. The XRD results showed that these samples crystallized, mainly forming wollastonite (CaSiO3) and diopside (CaMgSi2O6), but combeite (Na2Ca2Si3O9) crystalline phase was also detected. Besides in vitro bioactivity, cytotoxicity and osteoblast adhesion and proliferation tests were applied after all characterizations, and the formulation comprising 70% glass was demonstrated to be promising for further in vivo studies. PMID:28772783

Formulation of portland composite cement using waste glass as a supplementary cementitious material

NASA Astrophysics Data System (ADS)

Manullang, Ria Julyana; Samadhi, Tjokorde Walmiki; Purbasari, Aprilina

2017-09-01

Utilization of waste glass in cement is an attractive options because of its pozzolanic behaviour and the market of glass-composite cement is potentially available. The objective of this research is to evaluate the formulation of waste glass as supplementary cementitious material (SCM) by an extreme vertices mixture experiment, in which clinker, waste glass and gypsum proportions are chosen as experimental variables. The composite cements were synthesized by mixing all of powder materials in jar mill. The compressive strength of the composite cement mortars after being cured for 28 days ranges between 229 to 268 kg/cm2. Composite cement mortars exhibit lower compressive strength than ordinary Portland cement (OPC) mortars but is still capable of meeting the SNI 15-7064-2004 standards. The highest compressive strength is obtained by shifting the cement blend composition to the direction of increasing clinker and gypsum proportions as well as reducing glass proportion. The lower compressive strength of composite cement is caused by expansion due to ettringite and ASR gel. Based on the experimental result, the composite cement containing 80% clinker, 15% glass and 5% gypsum has the highest compressive strength. As such, the preliminary technical feasibility of reuse of waste glass as SCM has been confirmed.

Turning nuclear waste into glass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pegg, Ian L.

2015-02-15

Vitrification has emerged as the treatment option of choice for the most dangerous radioactive waste. But dealing with the nuclear waste legacy of the Cold War will require state-of-the-art facilities and advanced glass formulations.

Practical Considerations for Determination of Glass Transition Temperature of a Maximally Freeze Concentrated Solution.

PubMed

Pansare, Swapnil K; Patel, Sajal Manubhai

2016-08-01

Glass transition temperature is a unique thermal characteristic of amorphous systems and is associated with changes in physical properties such as heat capacity, viscosity, electrical resistance, and molecular mobility. Glass transition temperature for amorphous solids is referred as (T g), whereas for maximally freeze concentrated solution, the notation is (T g'). This article is focused on the factors affecting determination of T g' for application to lyophilization process design and frozen storage stability. Also, this review provides a perspective on use of various types of solutes in protein formulation and their effect on T g'. Although various analytical techniques are used for determination of T g' based on the changes in physical properties associated with glass transition, the differential scanning calorimetry (DSC) is the most commonly used technique. In this article, an overview of DSC technique is provided along with brief discussion on the alternate analytical techniques for T g' determination. Additionally, challenges associated with T g' determination, using DSC for protein formulations, are discussed. The purpose of this review is to provide a practical industry perspective on determination of T g' for protein formulations as it relates to design and development of lyophilization process and/or for frozen storage; however, a comprehensive review of glass transition temperature (T g, T g'), in general, is outside the scope of this work.

SLUDGE BATCH 6/TANK 40 SIMULANT CHEMICAL PROCESS CELL SIMULATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koopman, David

2010-04-28

Phase III simulant flowsheet testing was completed using the latest composition estimates for SB6/Tank 40 feed to DWPF. The goals of the testing were to determine reasonable operating conditions and assumptions for the startup of SB6 processing in the DWPF. Testing covered the region from 102-159% of the current DWPF stoichiometric acid equation. Nitrite ion concentration was reduced to 90 mg/kg in the SRAT product of the lowest acid run. The 159% acid run reached 60% of the DWPF Sludge Receipt and Adjustment Tank (SRAT) limit of 0.65 lb H2/hr, and then sporadically exceeded the DWPF Slurry Mix Evaporator (SME)more » limit of 0.223 lb H2/hr. Hydrogen generation rates peaked at 112% of the SME limit, but higher than targeted wt% total solids levels may have been partially responsible for rates seen. A stoichiometric factor of 120% met both objectives. A processing window for SB6 exists from 102% to something close to 159% based on the simulant results. An initial recommendation for SB6 processing is at 115-120% of the current DWPF stoichiometric acid equation. The addition of simulated Actinide Removal Process (ARP) and Modular Caustic Side Solvent Extraction Unit (MCU) streams to the SRAT cycle had no apparent impact on the preferred stoichiometric factor. Hydrogen generation occurred continuously after acid addition in three of the four tests. The three runs at 120%, 118.4% with ARP/MCU, and 159% stoichiometry were all still producing around 0.1 lb hydrogen/hr at DWPF scale after 36 hours of boiling in the SRAT. The 120% acid run reached 23% of the SRAT limit and 37% of the SME limit. Conversely, nitrous oxide generation was subdued compared to previous sludge batches, staying below 29 lb/hr in all four tests or about a fourth as much as in comparable SB4 testing. Two processing issues, identified during SB6 Phase II flowsheet testing and qualification simulant testing, were monitored during Phase III. Mercury material balance closure was impacted by acid stoichiometry, and significant mercury was not accounted for in the highest acid run. Coalescence of elemental mercury droplets in the mercury water wash tank (MWWT) appeared to degrade with increasing stoichiometry. Observations were made of mercury scale formation in the SRAT condenser and MWWT. A tacky mercury amalgam with Rh, Pd, and Cu, plus some Ru and Ca formed on the impeller at 159% acid. It contained a significant fraction of the available Pd, Cu, and Rh as well as about 25% of the total mercury charged. Free (elemental) mercury was found in all of the SME products. Ammonia scrubbers were used during the tests to capture off-gas ammonia for material balance purposes. Significant ammonium ion formation was again observed during the SRAT cycle, and ammonia gas entered the off-gas as the pH rose during boiling. Ammonium ion production was lower than in the SB6 Phase II and the qualification simulant testing. Similar ammonium ion formation was seen in the ARP/MCU simulation as in the 120% flowsheet run. A slightly higher pH caused most of the ammonium to vaporize and collect in the ammonia scrubber reflux solution. Two periods of foaminess were noted. Neither required additional antifoam to control the foam growth. A steady foam layer formed during reflux in the 120% acid run. It was about an inch thick, but was 2-3 times more volume of bubbles than is typically seen during reflux. A similar foam layer also was seen during caustic boiling of the simulant during the ARP addition. While frequently seen with the radioactive sludge, foaminess during caustic boiling with simulants has been relatively rare. Two further flowsheet tests were performed and will be documented separately. One test was to evaluate the impact of process conditions that match current DWPF operation (lower rates). The second test was to evaluate the impact of SRAT/SME processing on the rheology of a modified Phase III simulant that had been made five times more viscous using ultrasonication.« less

Practical fundamentals of glass, rubber, and plastic sterile packaging systems.

PubMed

Sacha, Gregory A; Saffell-Clemmer, Wendy; Abram, Karen; Akers, Michael J

2010-01-01

Sterile product packaging systems consist of glass, rubber, and plastic materials that are in intimate contact with the formulation. These materials can significantly affect the stability of the formulation. The interaction between the packaging materials and the formulation can also affect the appropriate delivery of the product. Therefore, a parenteral formulation actually consists of the packaging system as well as the product that it contains. However, the majority of formulation development time only considers the product that is contained in the packaging system. Little time is spent studying the interaction of the packaging materials with the contents. Interaction between the packaging and the contents only becomes a concern when problems are encountered. For this reason, there are few scientific publications that describe the available packaging materials, their advantages and disadvantages, and their important product attributes. This article was created as a reference for product development and describes some of the packaging materials and systems that are available for parenteral products.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marra, James; Kim, Dong -Sang; Maio, Vincent

A number of waste components in US defense high level radioactive wastes (HLW) have proven challenging for current Joule heated ceramic melter (JHCM) operations and have limited the ability to increase waste loadings beyond already realized levels. Many of these “troublesome" waste species cause crystallization in the glass melt that can negatively impact product quality or have a deleterious effect on melter processing. Recent efforts at US Department of Energy laboratories have focused on understanding crystallization behavior within HLW glass melts and investigating approaches to mitigate the impacts of crystallization so that increases in waste loading can be realized. Advancedmore » glass formulations have been developed to highlight the unique benefits of next-generation melter technologies such as the Cold Crucible Induction Melter (CCIM). Crystal-tolerant HLW glasses have been investigated to allow sparingly soluble components such as chromium to crystallize in the melter but pass out of the melter before accumulating.The Hanford site AZ-101 tank waste composition represents a waste group that is waste loading limited primarily due to high concentrations of Fe 2O 3 (also with high Al 2O 3 concentrations). Systematic glass formulation development utilizing slightly higher process temperatures and higher tolerance to spinel crystals demonstrated that an increase in waste loading of more than 20% could be achieved for this waste composition, and by extension higher loadings for wastes in the same group. An extended duration CCIM melter test was conducted on an AZ-101 waste simulant using the CCIM platform at the Idaho National Laboratory (INL). The melter was continually operated for approximately 80 hours demonstrating that the AZ-101 high waste loading glass composition could be readily processed using the CCIM technology. The resulting glass was close to the targeted composition and exhibited excellent durability in both the as poured state and after being slowly cooled according to the canister centerline cooling (CCC) profile. Glass formulation development was also completed on other Hanford tank wastes that were identified to further challenge waste loading due to the presence of appreciable quantities (>750 g) of plutonium in the waste tanks. In addition to containing appreciable Pu quantities, the C-102 waste tank and the 244-TX waste tank contain high concentrations of aluminum and iron, respectively that will further challenge vitrification processing. Glass formulation testing also demonstrated that high waste loadings could be achieved with these tank compositions using the attributes afforded by the CCIM technology.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahmad, Faiz, E-mail: faizahmad@petronas.com.my; Ullah, Sami; Aziz, Hammad, E-mail: engr.hammad.aziz03@gmail.com

The results of influence of glass fiber addition into the basic intumescent coating formulation towards the enhancement of its thermal insulation properties are presented. The intumescent coatings were formulated from expandable graphite, ammonium polyphosphate, melamine, boric acid, bisphenol A epoxy resin BE-188, polyamide amine H-2310 hardener and fiberglass (FG) of length 3.0 mm. Eight intumescent formulations were developed and the samples were tested for their fire performance by burning them at 450°C, 650°C and 850°C in the furnace for two hours. The effects of each fire test at different temperatures; low and high temperature were evaluated. Scanning Electron Microscope, X-Ray Diffractionmore » technique and Thermo Gravimetric Analysis were conducted on the samples to study the morphology, the chemical components of char and the residual weight of the coatings. The formulation, FG08 containing 7.0 wt% glass fiber provided better results with enhanced thermal insulation properties of the coatings.« less

DWPF DECON FRIT SUPERNATE ANALYSIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peeler, D.; Crawford, C.

2010-09-22

The Savannah River National Laboratory (SRNL) has been requested to perform analyses on samples of the Defense Waste Processing Facility (DWPF) decon frit slurry (i.e., supernate samples and sump solid samples). Four 1-L liquid slurry samples were provided to SRNL by Savannah River Remediation (SRR) from the 'front-end' decon activities. Additionally, two 1-L sump solids samples were provided to SRNL for compositional and physical analysis. This report contains the results of the supernate analyses, while the solids (sump and slurry) results will be reported in a supplemental report. The analytical data from the decon frit supernate indicate that all ofmore » the radionuclide, organic, and inorganic concentrations met the limits in Revision 4 of the Effluent Treatment Plant (ETP) Waste Acceptance Criteria (WAC) with the exception of boron. The ETP WAC limit for boron is 15.0 mg/L while the average measured concentration (based on quadruplicate analysis) was 15.5 mg/L. The measured concentrations of Li, Na, and Si were also relatively high in the supernate analysis. These results are consistent with the relatively high measured value of B given the compositional make-up of Frit 418. Given these results, it was speculated that either (a) Frit 418 was dissolving into the supernate or aqueous fraction and/or (b) fine frit particulates were carried forward to the analytical instrument based on the sampling procedure used (i.e., the supernate samples were not filtered - only settled with the liquid fraction being transferred with a pipette). To address this issue, a filtered supernate sample (using a 0.45 um filter) was prepared and submitted for analysis. The results of the filtered sample were consistent with 'unfiltered or settled' sample - relatively high values of B, Li, Na, and Si were found. This suggests that Frit 418 is dissolving in the liquid phase which could be enhanced by the high surface area of the frit fines or particulates in suspension. Based on the results of this study, it is recommended that DWPF re-evaluate the technical basis for the B WAC limit (the only component that exceeds the ETP WAC limit from the supernate analyses) or assess if a waiver or exception can be obtained for exceeding this limit. Given the possible dissolution of B, Li, Na, and Si into the supernate (due to dissolution of frit), DWPF may need to assess if the release of these frit components into the supernate are a concern for the disposal options being considered. It should be noted that the results of this study may not be representative of future decon frit solutions or sump/slurry solids samples. Therefore, future DWPF decisions regarding the possible disposal pathways for either the aqueous or solid portions of the Decon Frit system need to factor in the potential differences. More specifically, introduction of a different frit or changes to other DWPF flowsheet unit operations (e.g., different sludge batch or coupling with other process streams) may impact not only the results but also the conclusions regarding acceptability with respect to the ETF WAC limits.« less

Technical Status Report: Preliminary Glass Formulation Report for INEEL HAW. Revision 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peeler, D.; Reamer, I.; Vienna, J.

1998-03-01

Preliminary glass formulation work has been initiated at Pacific Northwest National Laboratory (PNNL) and the Savannah River Technology Center (SRTC) to support immobilization efforts of Idaho National Engineering and Environmental Laboratory (INEEL) high activity waste (HAW). Based on current pretreatment flow sheet assumptions, several glasses were fabricated and tested using an average `All Blend` waste stream composition which is dominated by the presence of ZrO{sub 2} (i.e., approximately 80 wt percent). The results of this initial work show that immobilization via vitrification is a viable option for a specific INEEL HAW waste stream. Waste loadings of at least 19 wtmore » percent can be achieved for the `All Blend` stream while maintaining targeted processing and product performance criteria. This waste loading translates into a ZrO{sub 2} content in excess of 15 wt percent in the final glass waste form. Frits developed for this work are based in the alkali borosilicate system. Although the results indicate that vitrification can be used to immobilize the `All Blend` waste stream, the glass compositions are by no means optimized.« less

Glass Development for Treatment of LANL Evaporator Bottoms Waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

DE Smith; GF Piepel; GW Veazey

1998-11-20

Vitrification is an attractive treatment option for meeting the stabilization and final disposal requirements of many plutonium (Pu) bearing materials and wastes at the Los Alamos National Laboratory (LANL) TA-55 facility, Rocky Flats Environmental Technology Site (RFETS), Hanford, and other Department of Energy (DOE) sites. The Environmental Protection Agency (EPA) has declared that vitrification is the "best demonstrated available technology" for high- level radioactive wastes (HLW) (Federal Register 1990) and has produced a handbook of vitriilcation technologies for treatment of hazardous and radioactive waste (US EPA, 1992). This technology has been demonstrated to convert Pu-containing materials (Kormanos, 1997) into durablemore » (Lutze, 1988) and accountable (Forsberg, 1995) waste. forms with reduced need for safeguarding (McCulhun, 1996). The composition of the Evaporator Bottoms Waste (EVB) at LANL, like that of many other I%-bearing materials, varies widely and is generally unpredictable. The goal of this study is to optimize the composition of glass for EVB waste at LANL, and present the basic techniques and tools for developing optimized glass compositions for other Pu-bearing materials in the complex. This report outlines an approach for glass formulation with fixed property restrictions, using glass property-composition databases. This approach is applicable to waste glass formulation for many variable waste streams and vitrification technologies.. Also reported are the preliminary property data for simulated evaporator bottom glasses, including glass viscosity and glass leach resistance using the Toxicity Characteristic Leaching Procedure (TCLP).« less

Thermodynamic model of natural, medieval and nuclear waste glass durability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C.M.; Plodinec, M.J.

1983-01-01

A thermodynamic model of glass durability based on hydration of structural units has been applied to natural glass, medieval window glasses, and glasses containing nuclear waste. The relative durability predicted from the calculated thermodynamics correlates directly with the experimentally observed release of structural silicon in the leaching solution in short-term laboratory tests. By choosing natural glasses and ancient glasses whose long-term performance is known, and which bracket the durability of waste glasses, the long-term stability of nuclear waste glasses can be interpolated among these materials. The current Savannah River defense waste glass formulation is as durable as natural basalt frommore » the Hanford Reservation (10/sup 6/ years old). The thermodynamic hydration energy is shown to be related to the bond energetics of the glass. 69 references, 2 figures, 1 table.« less

Study of the glass formation of high temperature superconductors

NASA Technical Reports Server (NTRS)

Ethridge, Edwin C.; Kaukler, William F.; Rolin, Terry

1992-01-01

A number of compositions of ceramic oxide high T(sub c) superconductors were elevated for their glass formation ability by means of rapid thermal analysis during quenching, optical, and electron microscopy of the quenched samples, and with subsequent DSC measurements. Correlations between experimental measurements and the methodical composition changes identified the formulations of superconductors that can easily form glass. The superconducting material was first formed as a glass; then, with subsequent devitrification, it was formed into a bulk crystalline superconductor by a series of processing methods.

Mercury Reduction and Removal from High Level Waste at the Defense Waste Processing Facility - 12511

DOE Office of Scientific and Technical Information (OSTI.GOV)

Behrouzi, Aria; Zamecnik, Jack

2012-07-01

The Defense Waste Processing Facility processes legacy nuclear waste generated at the Savannah River Site during production of enriched uranium and plutonium required by the Cold War. The nuclear waste is first treated via a complex sequence of controlled chemical reactions and then vitrified into a borosilicate glass form and poured into stainless steel canisters. Converting the nuclear waste into borosilicate glass is a safe, effective way to reduce the volume of the waste and stabilize the radionuclides. One of the constituents in the nuclear waste is mercury, which is present because it served as a catalyst in the dissolutionmore » of uranium-aluminum alloy fuel rods. At high temperatures mercury is corrosive to off-gas equipment, this poses a major challenge to the overall vitrification process in separating mercury from the waste stream prior to feeding the high temperature melter. Mercury is currently removed during the chemical process via formic acid reduction followed by steam stripping, which allows elemental mercury to be evaporated with the water vapor generated during boiling. The vapors are then condensed and sent to a hold tank where mercury coalesces and is recovered in the tank's sump via gravity settling. Next, mercury is transferred from the tank sump to a purification cell where it is washed with water and nitric acid and removed from the facility. Throughout the chemical processing cell, compounds of mercury exist in the sludge, condensate, and off-gas; all of which present unique challenges. Mercury removal from sludge waste being fed to the DWPF melter is required to avoid exhausting it to the environment or any negative impacts to the Melter Off-Gas system. The mercury concentration must be reduced to a level of 0.8 wt% or less before being introduced to the melter. Even though this is being successfully accomplished, the material balances accounting for incoming and collected mercury are not equal. In addition, mercury has not been effectively purified and collected in the Mercury Purification Cell (MPC) since 2008. A significant cleaning campaign aims to bring the MPC back up to facility housekeeping standards. Two significant investigations are being undertaken to restore mercury collection. The SMECT mercury pump has been removed from the tank and will be functionally tested. Also, research is being conducted by the Savannah River National Laboratory to determine the effects of antifoam addition on the behavior of mercury. These path forward items will help us better understand what is occurring in the mercury collection system and ultimately lead to an improved DWPF production rate and mercury recovery rate. (authors)« less

Stability of an extemporaneous oral liquid aprepitant formulation.

PubMed

Dupuis, L Lee; Lingertat-Walsh, Karen; Walker, Scott E

2009-06-01

Aprepitant is currently recommended for the prevention of acute antineoplastic-induced nausea and vomiting in adults receiving highly emetogenic therapy. The lack of an oral liquid dosage form is one barrier to its use in children. The purpose of this study was to develop a stable oral liquid formulation of aprepitant using the marketed aprepitant capsules. Aprepitant 20-mg/mL oral liquid was prepared from 125-mg capsule contents in Orablend(R). Twelve test samples were prepared: six packaged in amber glass and six in polyethylene terephthalate (PET) containers, three of each stored at either 23 degrees C or 4 degrees C. The physical characteristics of the oral aprepitant liquid stored in amber glass bottles were evaluated at the time of compounding and on days 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, and 91. The aprepitant content of three test solutions of each container type and storage temperature was determined using a stability-indicating assay at 5, 9, 14, 29, 48, 62, 73, and 111 days after compounding. All samples stored in glass demonstrated suitable physical characteristics and those stored in either glass or PET retained more than 94.0% of the initial concentration. Based on the higher limit of the 95% confidence interval of the degradation rate, suspensions stored at 23 degrees C achieved 10% loss within 66 to 85 days, compared to greater than 100 days when stored at 4 degrees C. The extemporaneous aprepitant oral suspension formulation described is physically and chemically stable for at least 90 days when refrigerated. The bioavailability of this formulation is unknown.

The Influence of Formulation and Manufacturing Process Parameters on the Characteristics of Lyophilized Orally Disintegrating Tablets

PubMed Central

Jones, Rhys J.; Rajabi-Siahboomi, Ali; Levina, Marina; Perrie, Yvonne; Mohammed, Afzal R.

2011-01-01

Gelatin is a principal excipient used as a binder in the formulation of lyophilized orally disintegrating tablets. The current study focuses on exploiting the physicochemical properties of gelatin by varying formulation parameters to determine their influence on orally disintegrating tablet (ODT) characteristics. Process parameters, namely pH and ionic strength of the formulations, and ball milling were investigated to observe their effects on excipient characteristics and tablet formation. The properties and characteristics of the formulations and tablets which were investigated included: glass transition temperature, wettability, porosity, mechanical properties, disintegration time, morphology of the internal structure of the freeze-dried tablets, and drug dissolution. The results from the pH study revealed that adjusting the pH of the formulation away from the isoelectric point of gelatin, resulted in an improvement in tablet disintegration time possibly due to increase in gelatin swelling resulting in greater tablet porosity. The results from the ionic strength study revealed that the inclusion of sodium chloride influenced tablet porosity, tablet morphology and the glass transition temperature of the formulations. Data from the milling study showed that milling the excipients influenced formulation characteristics, namely wettability and powder porosity. The study concludes that alterations of simple parameters such as pH and salt concentration have a significant influence on formulation of ODT. PMID:24310589

Application of inorganic carrier-based formulations of fluorescent pseudomonads and Piriformospora indica on tomato plants and evaluation of their efficacy.

PubMed

Sarma, M V R K; Kumar, V; Saharan, K; Srivastava, R; Sharma, A K; Prakash, A; Sahai, V; Bisaria, V S

2011-08-01

Fluorescent pseudomonads are widely used as bioinoculants for improving plant growth and controlling phytopathogenic fungi. Piriformospora indica (Pi), a symbiotic root endophyte, also has beneficial effects on a number of plants. The present study focuses on the improvement of growth yields of tomato plants and control of Fusarium wilt using inorganic carrier-based formulations of two fluorescent pseudomonad strains (R62 and R81) and Pi. The inorganic carrier-based formulations of pseudomonad strains and Pi were tested for plant growth promotion of tomato plants under glass house and field conditions. In controlled glass house experiments, 8·8-fold increase in dry root weight and 8·6-fold increase in dry shoot weight were observed with talcum powder-based consortium formulation of R81 and Pi. Field trial experiments ascertained the glfass house results with a considerable amount of increase in plant growth responses, and amongst all the treatments, R81 + Pi treatment performed consistently well in field conditions with an increase of 2·6-, 3·1- and 3·9-fold increase in dry root weight, shoot weight and fruit yield, respectively. The fluorescent pseudomonad R81 and Pi also acted as biocontrol agents, as their treatments could control the incidence of wilt disease caused by Fusarium oxysporum f.sp. lycopersici in tomato plants under glass house conditions. The culture broths of pseudomonads R62, R81 and Pi were successfully used for development of talcum- and vermiculite-based bioinoculant formulations. In controlled glasshouse experiments, the talcum-based bioinoculant formulations performed significantly better over vermiculite-based formulations. In field experiments the talcum-based consortium formulation of pseudomonad R81 and Pi was most effective. This study suggests that the formulations of pseudomonad strains (R62 and R81) and Pi can be used as bioinoculants for improving the productivity of tomato plants. The application of such formulations is a step forward towards sustainable agriculture. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Newell, J; Miller, D; Stone, M

The Savannah River National Laboratory (SRNL) was tasked to provide an assessment of the downstream impacts to the Defense Waste Processing Facility (DWPF) of decisions regarding the implementation of Al-dissolution to support sludge mass reduction and processing. Based on future sludge batch compositional projections from the Liquid Waste Organization's (LWO) sludge batch plan, assessments have been made with respect to the ability to maintain comparable projected operating windows for sludges with and without Al-dissolution. As part of that previous assessment, candidate frits were identified to provide insight into melt rate for average sludge batches representing with and without Al-dissolution flowsheets.more » Initial melt rate studies using the melt rate furnace (MRF) were performed using five frits each for Cluster 2 and Cluster 4 compositions representing average without and with Al-dissolution. It was determined, however, that the REDOX endpoint (Fe{sup 2+}/{Sigma}Fe for the glass) for Clusters 2 and 4 resulted in an overly oxidized feed which negatively affected the initial melt rate tests. After the sludge was adjusted to a more reduced state, additional testing was performed with frits that contained both high and low concentrations of sodium and boron oxides. These frits were selected strictly based on the ability to ascertain compositional trends in melt rate and did not necessarily apply to any acceptability criteria for DWPF processing. The melt rate data are in general agreement with historical trends observed at SRNL and during processing of SB3 (Sludge Batch 3)and SB4 in DWPF. When MAR acceptability criteria were applied, Frit 510 was seen to have the highest melt rate at 0.67 in/hr for Cluster 2 (without Al-dissolution), which is compositionally similar to SB4. For Cluster 4 (with Al-dissolution), which is compositionally similar to SB3, Frit 418 had the highest melt rate at 0.63 in/hr. Based on this data, there appears to be a slight advantage of the Frit 510 based system without Al-dissolution relative to the Frit 418 based system with Al-dissolution. Though the without aluminum dissolution scenario suggests a slightly higher melt rate with frit 510, several points must be taken into consideration: (1) The MRF does not have the ability to assess liquid feeds and, thus, rheology impacts. Instead, the MRF is a 'static' test bed in which a mass of dried melter feed (SRAT product plus frit) is placed in an 'isothermal' furnace for a period of time to assess melt rate. These conditions, although historically effective in terms of identifying candidate frits for specific sludge batches and mapping out melt rate versus waste loading trends, do not allow for assessments of the potential impact of feed rheology on melt rate. That is, if the rheological properties of the slurried melter feed resulted in the mounding of the feed in the melter (i.e., the melter feed was thick and did not flow across the cold cap), melt rate and/or melter operations (i.e., surges) could be negatively impacted. This could affect one or both flowsheets. (2) Waste throughput factors were not determined for Frit 510 and Frit 418 over multiple waste loadings. In order to provide insight into the mission life versus canister count question, one needs to define the maximum waste throughput for both flowsheets. Due to funding limitations, the melt rate testing only evaluated melt rate at a fixed waste loading. (3) DWPF will be processing SB5 through their facility in mid-November 2008. Insight into the over arching questions of melt rate, waste throughput, and mission life can be obtained directly from the facility. It is recommended that processing of SB5 through the facility be monitored closely and that data be used as input into the decision making process on whether to implement Al-dissolution for future sludge batches.« less

Organics Characterization Of DWPF Alternative Reductant Simulants, Glycolic Acid, And Antifoam 747

DOE Office of Scientific and Technical Information (OSTI.GOV)

White, T. L.; Wiedenman, B. J.; Lambert, D. P.

The present study examines the fate of glycolic acid and other organics added in the Chemical Processing Cell (CPC) of the Defense Waste Processing Facility (DWPF) as part of the glycolic alternate flowsheet. Adoption of this flowsheet is expected to provide certain benefits in terms of a reduction in the processing time, a decrease in hydrogen generation, simplification of chemical storage and handling issues, and an improvement in the processing characteristics of the waste stream including an increase in the amount of nitrate allowed in the CPC process. Understanding the fate of organics in this flowsheet is imperative because tankmore » farm waste processed in the CPC is eventually immobilized by vitrification; thus, the type and amount of organics present in the melter feed may affect optimal melt processing and the quality of the final glass product as well as alter flammability calculations on the DWPF melter off gas. To evaluate the fate of the organic compounds added as the part of the glycolic flowsheet, mainly glycolic acid and antifoam 747, samples of simulated waste that was processed using the DWPF CPC protocol for tank farm sludge feed were generated and analyzed for organic compounds using a variety of analytical techniques at the Savannah River National Laboratory (SRNL). These techniques included Ion Chromatography (IC), Gas Chromatography-Mass Spectrometry (GC-MS), Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES), and Nuclear Magnetic Resonance (NMR) Spectroscopy. A set of samples were also sent to the Catholic University of America Vitreous State Laboratory (VSL) for analysis by NMR Spectroscopy at the University of Maryland, College Park. Analytical methods developed and executed at SRNL collectively showed that glycolic acid was the most prevalent organic compound in the supernatants of Slurry Mix Evaporator (SME) products examined. Furthermore, the studies suggested that commercially available glycolic acid contained minor amounts of impurities such as formic and diglycolic acid that were then carried over in the SME products. Oxalic acid present in the simulated tank farm waste was also detected. Finally, numerous other compounds, at low concentrations, were observed present in etheric extracts of aqueous supernate solutions of the SME samples and are thought to be breakdown products of antifoam 747. The data collectively suggest that although addition of glycolic acid and antifoam 747 will introduce a number of impurities and breakdown products into the melter feed, the concentrations of these organics is expected to remain low and may not significantly impact REDOX or off-gas flammability predictions. In the SME products examined presently, which contained variant amounts of glycolic acid and antifoam 747, no unexpected organic degradation product was found at concentrations above 500 mg/kg, a reasonable threshold concentration for an organic compound to be taken into account in the REDOX modeling. This statement does not include oxalic or formic acid that were sometimes observed above 500 mg/kg and acetic acid that has an analytical detection limit of 1250 mg/kg due to high glycolate concentration in the SME products tested. Once a finalized REDOX equation has been developed and implemented, REDOX properties of known organic species will be determined and their impact assessed. Although no immediate concerns arose during the study in terms of a negative impact of organics present in SME products of the glycolic flowsheet, evidence of antifoam degradation suggest that an alternative antifoam to antifoam 747 is worth considering. The determination and implementation of an antifoam that is more hydrolysis resistant would have benefits such as increasing its effectiveness over time and reducing the generation of degradation products.« less

Results of Hg speciation testing on DWPF SMECT-4, SMECT-6, and RCT-2 samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C. J.

2016-02-04

The Savannah River National Laboratory (SRNL) was tasked with preparing and shipping samples for Hg speciation by Eurofins Frontier Global Sciences, Inc. in Seattle, WA on behalf of the Savannah River Remediation (SRR) Mercury Task Team.i,ii The fifteenth shipment of samples was designated to include Defense Waste Processing Facility (DWPF) Slurry Mix Evaporator Condensate Tank (SMECT) samples from Sludge Receipt and Adjustment Tank (SRAT) Batch 738 and a Recycle Condensate Tank (RCT) sample from SRAT Batch 736. The DWPF sample designations for the three samples analyzed are provided in Table 1. The Batch 738 ‘Baseline’ SMECT sample was taken priormore » to Precipitate Reactor Feed Tank (PRFT) addition and concentration and therefore, precedes the SMECT-5 sample reported previously. iii The Batch 738 ‘End of SRAT Cycle’ SMECT sample was taken at the conclusion of SRAT operations for this batch (PRFT addition/concentration, acid additions, initial concentration, MCU addition, and steam stripping). Batch 738 experienced a sludge slurry carryover event, which introduced sludge solids to the SMECT that were particularly evident in the SMECT-5 sample, but less evident in the ‘End of SRAT Cycle’ SMECT-6 sample. The Batch 736 ‘After SME’ RCT sample was taken after completion of SMECT transfers at the end of the SME cycle.« less

DATA SUMMARY REPORT SMALL SCALE MELTER TESTING OF HLW ALGORITHM GLASSES MATRIX1 TESTS VSL-07S1220-1 REV 0 7/25/07

DOE Office of Scientific and Technical Information (OSTI.GOV)

KRUGER AA; MATLACK KS; PEGG IL

2011-12-29

Eight tests using different HLW feeds were conducted on the DM100-BL to determine the effect of variations in glass properties and feed composition on processing rates and melter conditions (off-gas characteristics, glass processing, foaming, cold cap, etc.) at constant bubbling rate. In over seven hundred hours of testing, the property extremes of glass viscosity, electrical conductivity, and T{sub 1%}, as well as minimum and maximum concentrations of several major and minor glass components were evaluated using glass compositions that have been tested previously at the crucible scale. Other parameters evaluated with respect to glass processing properties were +/-15% batching errorsmore » in the addition of glass forming chemicals (GFCs) to the feed, and variation in the sources of boron and sodium used in the GFCs. Tests evaluating batching errors and GFC source employed variations on the HLW98-86 formulation (a glass composition formulated for HLW C-106/AY-102 waste and processed in several previous melter tests) in order to best isolate the effect of each test variable. These tests are outlined in a Test Plan that was prepared in response to the Test Specification for this work. The present report provides summary level data for all of the tests in the first test matrix (Matrix 1) in the Test Plan. Summary results from the remaining tests, investigating minimum and maximum concentrations of major and minor glass components employing variations on the HLW98-86 formulation and glasses generated by the HLW glass formulation algorithm, will be reported separately after those tests are completed. The test data summarized herein include glass production rates, the type and amount of feed used, a variety of measured melter parameters including temperatures and electrode power, feed sample analysis, measured glass properties, and gaseous emissions rates. More detailed information and analysis from the melter tests with complete emission chemistry, glass durability, and melter operating details will be provided in the final report. A summary of the tests that were conducted is provided in Table 1. Each of the seven tests was of nominally one hundred hours in duration. Test B was conducted in two equal segments: the first with nominal additives, and the second with the replacement of borax with a mixture of boric acid and soda ash to determine the effect of alternative OPC sources on production rates and processing characteristics. Interestingly, sugar additions were required near mid points of Tests W and Z to reduce excessive foaming that severely limited feed processing rates. The sugar additions were very effective in recovering manageable processing conditions, albeit over the relatively short remainder of the test duration. Tests W and Z employed the highest melt viscosities but not by a particularly wide margin. Other tests, which did not exhibit such foaming Issues, employed higher concentrations of manganese or iron or both. These results highlight the need for the development of protocols for the a priori determination of which HLW feeds will require sugar additions and the appropriate amounts of sugar to be added in order to control foaming (and maintain throughput) without over-reduction of the melt (which could lead to molten metal formation). In total, over 8,800 kg of feed was processed to produce over 3200 kg of glass. Steady-state processing rates were achieved, and no secondary sulfate phases were observed during any of the tests. Analysis was performed on samples of the glass product taken throughout the tests to verify composition and properties. Sampling and analysis was also performed on melter exhaust to determine the effect of the feed and glass changes on melter emissions.« less

Glass Waste Forms for Oak Ridge Tank Wastes: Fiscal Year 1998 Report for Task Plan SR-16WT-31, Task B

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andrews, M.K.

1999-05-10

Using ORNL information on the characterization of the tank waste sludges, SRTC performed extensive bench-scale vitrification studies using simulants. Several glass systems were tested to ensure the optimum glass composition (based on the glass liquidus temperature, viscosity and durability) is determined. This optimum composition will balance waste loading, melt temperature, waste form performance and disposal requirements. By optimizing the glass composition, a cost savings can be realized during vitrification of the waste. The preferred glass formulation was selected from the bench-scale studies and recommended to ORNL for further testing with samples of actual OR waste tank sludges.

Single-Phase Rare-Earth Oxide/Aluminum Oxide Glasses

NASA Technical Reports Server (NTRS)

Weber, J. K. Richard; Abadie, John G.; Hixson, April D.; Nordine, Paul C.

2006-01-01

Glasses that comprise rare-earth oxides and aluminum oxide plus, optionally, lesser amounts of other oxides, have been invented. The other oxide(s) can include SiO2, B2O3, GeO2, and/or any of a variety of glass-forming oxides that have been used heretofore in making a variety of common and specialty glasses. The glasses of the invention can be manufactured in bulk single-phase forms to ensure near uniformity in optical and mechanical characteristics, as needed for such devices as optical amplifiers, lasers, and optical waveguides (including optical fibers). These glasses can also be formulated to have high indices of refraction, as needed in some of such devices.

Glass formability of high T(sub c) Bi-Sr-Ca-Cu-O superconductors

NASA Technical Reports Server (NTRS)

Kaukler, William F.

1992-01-01

A number of compositions of ceramic oxide high T(sub c) superconductors were evaluated for their glass formation ability by means of rapid thermal analysis during quenching, optical and electron microscopy of the quenched samples, and with subsequent DSC measurements. Correlations between experimental measurements and the methodical composition changes identified the formulations of superconductors that can easily form glass. The superconducting material was first formed as a glass, then with subsequent devitrification it was formed into bulk crystalline superconductor by a series of processing methods.

Glass-ionomer cement formulations. II. The synthesis of novel polycarobxylic acids.

PubMed

Crisp, S; Kent, B E; Lewis, B G; Ferner, A J; Wilson, A D

1980-06-01

The synthesis of many polycarboxylic acids is reported. An account is given of their stability in aqueous solution and the properties of cements formed by their reaction with ion-leachable glasses. A copolymer of acrylic and itaconic acids was found to combine several favorable characteristics.

Glass binder development for a glass-bonded sodalite ceramic waste form

NASA Astrophysics Data System (ADS)

Riley, Brian J.; Vienna, John D.; Frank, Steven M.; Kroll, Jared O.; Peterson, Jacob A.; Canfield, Nathan L.; Zhu, Zihua; Zhang, Jiandong; Kruska, Karen; Schreiber, Daniel K.; Crum, Jarrod V.

2017-06-01

This paper discusses work to develop Na2O-B2O3-SiO2 glass binders for immobilizing LiCl-KCl eutectic salt waste in a glass-bonded sodalite waste form following electrochemical reprocessing of used metallic nuclear fuel. Here, five new glasses with ∼20 mass% Na2O were designed to generate waste forms with high sodalite. The glasses were then used to produce ceramic waste forms with a surrogate salt waste. The waste forms made using these new glasses were formulated to generate more sodalite than those made with previous baseline glasses for this type of waste. The coefficients of thermal expansion for the glass phase in the glass-bonded sodalite waste forms made with the new binder glasses were closer to the sodalite phase in the critical temperature region near and below the glass transition temperature than previous binder glasses used. These improvements should result in lower probability of cracking in the full-scale monolithic ceramic waste form, leading to better long-term chemical durability.

The U.S. Department of Energy - Office of Environmental Management Cooperation Program with the Russian Federal Atomic Energy Agency (ROSATOM)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gerdes, K.D.; Holtzscheiter, E.W.

2006-07-01

The U.S. Department of Energy's (DOE) Office of Environmental Management (EM) has collaborated with the Russian Federal Atomic Energy Agency - Rosatom (formerly Minatom) for 14 years on waste management challenges of mutual concern. Currently, EM is cooperating with Rosatom to explore issues related to high-level waste and investigate Russian experience and technologies that could support EM site cleanup needs. EM and Rosatom are currently implementing six collaborative projects on high-level waste issues: 1) Advanced Melter Technology Application to the U.S. DOE Defense Waste Processing Facility (DWPF) - Cold Crucible Induction Heated Melter (CCIM); 2) - Design Improvements to themore » Cold Crucible Induction Heated Melter; 3) Long-term Performance of Hanford Low-Activity Glasses in Burial Environments; 4) Low-Activity-Waste (LAW) Glass Sulfur Tolerance; 5) Improved Retention of Key Contaminants of Concern in Low Temperature Immobilized Waste Forms; and, 6) Documentation of Mixing and Retrieval Experience at Zheleznogorsk. Preliminary results and the path forward for these projects will be discussed. An overview of two new projects 7) Entombment technology performance and methodology for the Future 8) Radiation Migration Studies at Key Russian Nuclear Disposal Sites is also provided. The purpose of this paper is to provide an overview of EM's objectives for participating in cooperative activities with the Russian Federal Atomic Energy Agency, present programmatic and technical information on these activities, and outline specific technical collaborations currently underway and planned to support DOE's cleanup and closure mission. (authors)« less

Tin Valence and Local Environments in Silicate Glasses as Determined From X-ray Absorption Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

McKeown,D.; Buechele, A.; Gan, H.

2008-01-01

X-ray absorption spectroscopy (XAS) was used to characterize the tin (Sn) environments in four borosilicate glass nuclear waste formulations, two silicate float glasses, and three potassium aluminosilicate glasses. Sn K-edge XAS data of most glasses investigated indicate Sn4+O6 units with average Sn-O distances near 2.03 Angstroms. XAS data for a float glass fabricated under reducing conditions show a mixture of Sn4+O6 and Sn2+O4 sites. XAS data for three glasses indicate Sn-Sn distances ranging from 3.43 to 3.53 Angstroms, that suggest Sn4+O6 units linking with each other, while the 4.96 Angstroms Sn-Sn distance for one waste glass suggests clustering of unlinkedmore » Sn4+O6 units.« less

Optically stimulated luminescence of borate glasses containing magnesia, quicklime, lithium and potassium carbonates

NASA Astrophysics Data System (ADS)

Valença, J. V. B.; Silveira, I. S.; Silva, A. C. A.; Dantas, N. O.; Antonio, P. L.; Caldas, L. V. E.; d'Errico, F.; Souza, S. O.

2017-11-01

The OSL characteristics of three different borate glass matrices containing magnesia (LMB), quicklime (LCB) or potassium carbonate (LKB) were examined. Five different formulations for each composition were produced using a melt-quenching method and analyzed in terms of both dose-response curves and OSL shape decay. The samples were irradiated using a 90Sr/90Y beta source with doses up to 30 Gy. Dose-response curves were plotted using the initial OSL intensity as the chosen parameter. The OSL analysis showed that LKB glasses are the most sensitive to beta irradiation. For the most sensitive LKB composition, the irradiation process was also done using a 60Co gamma source in a dose range from 200 to 800 Gy. In all cases, no saturation was observed. A fitting process using a three-term exponential function was performed for the most sensitive formulations of each composition, which suggested a similar behavior in the OSL decay.

Defense Waste Processing Facility Process Enhancements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bricker, Jonathan

2010-11-01

Jonathan Bricker provides an overview of process enhancements currently being done at the Defense Waste Processing Facility (DWPF) at SRS. Some of these enhancements include: melter bubblers; reduction in water use, and alternate reductant.

Impact of glycolate anion on aqueous corrosion in DWPF and downstream facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mickalonis, J. I.

2015-12-15

Glycolic acid is being evaluated as an alternate reductant in the preparation of high level waste for the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS). During processing, the glycolic acid may not be completely consumed with small quantities of the glycolate anion being carried forward to other high level waste (HLW) facilities. The impact of the glycolate anion on the corrosion of the materials of construction (MoC) throughout the waste processing system has not been previously evaluated. A literature review had revealed that corrosion data were not available for the MoCs in glycolic-bearing solutions applicable tomore » SRS systems. Data on the material compatibility with only glycolic acid or its derivative products were identified; however, data were limited for solutions containing glycolic acid or the glycolate anion.« less

Characterization Of The As-Received Sludge Batch 9 Qualification Sample (Htf-51-15-81)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pareizs, J.

Savannah River National Laboratory (SRNL) personnel have been requested to qualify the next sludge batch (Sludge Batch 9 – SB9) for processing at the Defense Waste Processing Facility (DWPF). To accomplish this task, Savannah River Remediation (SRR) has sent SRNL a 3-L slurried sample of Tank 51H (HTF-51-15-81) to be characterized, washed, and then used in a lab-scale demonstration of the DWPF flowsheet (potentially after combining with Tank 40H sludge). This report documents the first steps of the qualification process – characterization of the as-received Tank 51H qualification sample. These results will be used to support a reprojection of SB9more » by SRR from which final Tank 51H washing, frit development, and Chemical Processing Cell (CPC) activities will be based.« less

Sludge batch 9 simulant runs using the nitric-glycolic acid flowsheet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, D. P.; Williams, M. S.; Brandenburg, C. H.

Testing was completed to develop a Sludge Batch 9 (SB9) nitric-glycolic acid chemical process flowsheet for the Defense Waste Processing Facility’s (DWPF) Chemical Process Cell (CPC). CPC simulations were completed using SB9 sludge simulant, Strip Effluent Feed Tank (SEFT) simulant and Precipitate Reactor Feed Tank (PRFT) simulant. Ten sludge-only Sludge Receipt and Adjustment Tank (SRAT) cycles and four SRAT/Slurry Mix Evaporator (SME) cycles, and one actual SB9 sludge (SRAT/SME cycle) were completed. As has been demonstrated in over 100 simulations, the replacement of formic acid with glycolic acid virtually eliminates the CPC’s largest flammability hazards, hydrogen and ammonia. Recommended processingmore » conditions are summarized in section 3.5.1. Testing demonstrated that the interim chemistry and Reduction/Oxidation (REDOX) equations are sufficient to predict the composition of DWPF SRAT product and SME product. Additional reports will finalize the chemistry and REDOX equations. Additional testing developed an antifoam strategy to minimize the hexamethyldisiloxane (HMDSO) peak at boiling, while controlling foam based on testing with simulant and actual waste. Implementation of the nitric-glycolic acid flowsheet in DWPF is recommended. This flowsheet not only eliminates the hydrogen and ammonia hazards but will lead to shorter processing times, higher elemental mercury recovery, and more concentrated SRAT and SME products. The steady pH profile is expected to provide flexibility in processing the high volume of strip effluent expected once the Salt Waste Processing Facility starts up.« less

Thermal processing of EVA encapsulants and effects of formulation additives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pern, F.J.; Glick, S.H.

1996-05-01

The authors investigated the in-situ processing temperatures and effects of various formulation additives on the formation of ultraviolet (UV) excitable chromophores, in the thermal lamination and curing of ethylene-vinyl acetate (EVA) encapsulants. A programmable, microprocessor-controlled, double-bag vacuum laminator was used to study two commercial as formulated EVA films, A9918P and 15295P, and solution-cast films of Elvaxrm (EVX) impregnated with various curing agents and antioxidants. The results show that the actual measured temperatures of EVA lagged significantly behind the programmed profiles for the heating elements and were affected by the total thermal mass loaded inside the laminator chamber. The antioxidant Naugardmore » P{trademark}, used in the two commercial EVA formulations, greatly enhances the formation of UV-excitable, short chromophores upon curing, whereas other tested antioxidants show little effect. A new curing agent chosen specifically for the EVA formulation modification produces little or no effect on chromophore formation, no bubbling problems in the glass/EVX/glass laminates, and a gel content of {approximately}80% when cured at programmed 155{degrees}C for 4 min. Also demonstrated is the greater discoloring effect with higher concentrations of curing-generated chromophores.« less

Thermal processing of EVA encapsulants and effects of formulation additives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pern, F.J.; Glick, S.H.

1996-09-01

The authors investigated the in-situ processing temperatures and effects of various formulation additives on the formation of ultraviolet (UV) excitable chromophores in the thermal lamination and curing of ethylene-vinyl acetate (EVA) encapsulants. A programmable, microprocessor-controlled, double-bag vacuum laminator was used to study two commercial as-formulated EVA films. A9918P and 15295P, and solution-cast films of Elvax{trademark} (EVX) impregnated with various curing agents and antioxidants. The results show that the actual measured temperatures of EVA lagged significantly behind the programmed profiles for the heating elements and were affected by the total thermal mass loaded inside the laminator chamber. The antioxidant Naugard P{trademark},more » used in the two commercial EVA formulations, greatly enhances the formation of UV-excitable, short chromophores upon curing, whereas other tested antioxidants show little effect. A new curing agent chosen specifically for the EVA formulation modification produces little or no effect on chromophore formation, no bubbling problems in the glass/EVX/glass laminates, and a gel content of {approximately}80% when cured at programmed 155 C for 4 min. Also demonstrated is the greater discoloring effect with higher concentrations of curing-generated chromophores.« less

Influence of humidity on the phase behavior of API/polymer formulations.

PubMed

Prudic, Anke; Ji, Yuanhui; Luebbert, Christian; Sadowski, Gabriele

2015-08-01

Amorphous formulations of APIs in polymers tend to absorb water from the atmosphere. This absorption of water can induce API recrystallization, leading to reduced long-term stability during storage. In this work, the phase behavior of different formulations was investigated as a function of relative humidity. Indomethacin and naproxen were chosen as model APIs and poly(vinyl pyrrolidone) (PVP) and poly(vinyl pyrrolidone-co-vinyl acetate) (PVPVA64) as excipients. The formulations were prepared by spray drying. The water sorption in pure polymers and in formulations was measured at 25°C and at different values of relative humidity (RH=25%, 50% and 75%). Most water was absorbed in PVP-containing systems, and water sorption was decreasing with increasing API content. These trends could also be predicted in good agreement with the experimental data using the thermodynamic model PC-SAFT. Furthermore, the effect of absorbed water on API solubility in the polymer and on the glass-transition temperature of the formulations was predicted with PC-SAFT and the Gordon-Taylor equation, respectively. The absorbed water was found to significantly decrease the API solubility in the polymer as well as the glass-transition temperature of the formulation. Based on a quantitative modeling of the API/polymer phase diagrams as a function of relative humidity, appropriate API/polymer compositions can now be selected to ensure long-term stable amorphous formulations at given storage conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of Feed Composition on Cold-Cap Formation in Laboratory-Scale Melter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dixon, Derek R.; Schweiger, Michael J.; Lee, Seung Min

The development of advanced glass formulations are a part of the plan for reducing the cost and time for treatment and vitrification of the 210,000 m3 of nuclear waste at the Hanford Site in southeastern Washington State. One property of interest in this development is melt viscosity, which has a decisive influence on the rate of glass production. In an electric melter, the conversion process from feed-to-glass above the melt pool occurs in the cold cap. At the final stage of conversion when the glass-forming melt becomes connected, gas evolving reactions cause foaming. The melt viscosity affects foam stability. Threemore » glasses were formulated with viscosities of 1.5, 3.5, and 9.5 Pa s at 1150°C by varying the SiO2 content at the expense of B2O3, Li2O, and Na2O kept at constant proportions. Cold caps were produced by charging simulated high-alumina, high-level waste feeds in a laboratory-scale melter (LSM). The spread of the feed on the cold cap during charging and the cross-sectional structure of the final cold caps were compared. The amount of the foam and the size of the bubbles increased as the viscosity increased.« less

Glass binder development for a glass-bonded sodalite ceramic waste form

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riley, Brian J.; Vienna, John D.; Frank, Steven M.

This paper discusses work to develop Na 2O-B 2O 3-SiO 2 glass binders for immobilizing LiCl-KCl eutectic salt waste in a glass-bonded sodalite waste form following electrochemical reprocessing of used metallic nuclear fuel. In this paper, five new glasses with ~20 mass% Na 2O were designed to generate waste forms with high sodalite. The glasses were then used to produce ceramic waste forms with a surrogate salt waste. The waste forms made using these new glasses were formulated to generate more sodalite than those made with previous baseline glasses for this type of waste. The coefficients of thermal expansion formore » the glass phase in the glass-bonded sodalite waste forms made with the new binder glasses were closer to the sodalite phase in the critical temperature region near and below the glass transition temperature than previous binder glasses used. Finally, these improvements should result in lower probability of cracking in the full-scale monolithic ceramic waste form, leading to better long-term chemical durability.« less

Glass binder development for a glass-bonded sodalite ceramic waste form

DOE PAGES

Riley, Brian J.; Vienna, John D.; Frank, Steven M.; ...

2017-06-01

This paper discusses work to develop Na 2O-B 2O 3-SiO 2 glass binders for immobilizing LiCl-KCl eutectic salt waste in a glass-bonded sodalite waste form following electrochemical reprocessing of used metallic nuclear fuel. In this paper, five new glasses with ~20 mass% Na 2O were designed to generate waste forms with high sodalite. The glasses were then used to produce ceramic waste forms with a surrogate salt waste. The waste forms made using these new glasses were formulated to generate more sodalite than those made with previous baseline glasses for this type of waste. The coefficients of thermal expansion formore » the glass phase in the glass-bonded sodalite waste forms made with the new binder glasses were closer to the sodalite phase in the critical temperature region near and below the glass transition temperature than previous binder glasses used. Finally, these improvements should result in lower probability of cracking in the full-scale monolithic ceramic waste form, leading to better long-term chemical durability.« less

Chemical composition analysis and product consistency tests supporting refinement of the Nepheline model for the high aluminum Hanford Glass composition region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fox, K. M.; Edwards, T. B.; Mcclane, D. L.

2016-02-17

In this report, SRNL provides chemical analyses and Product Consistency Test (PCT) results for a series of simulated HLW glasses fabricated by Pacific Northwest National Laboratory (PNNL) as part of an ongoing nepheline crystallization study. The results of these analyses will be used to improve the ability to predict crystallization of nepheline as a function of composition and heat treatment for glasses formulated at high alumina concentrations.

Chemical composition analysis and product consistency tests supporting refinement of the Nepheline Model for the high aluminum Hanford glass composition region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fox, K. M.; Edwards, T. B.; Mcclane, D. L.

2016-03-01

In this report, Savannah River National Laboratory provides chemical analyses and Product Consistency Test (PCT) results for a series of simulated high level waste (HLW) glasses fabricated by Pacific Northwest National Laboratory (PNNL) as part of an ongoing nepheline crystallization study. The results of these analyses will be used to improve the ability to predict crystallization of nepheline as a function of composition and heat treatment for glasses formulated at high alumina concentrations.

Fiberglass goes green: Developing phosphate glass for use in biodegradable composites

NASA Astrophysics Data System (ADS)

Arendt, Christina Lee

Composite materials, such as the glass fiber reinforced polyester thermosets known as "fiberglass," are used in many applications. However, recycling processes for these materials are inefficient and not widely available. Specially engineered degradable polymers offer an opportunity to redesign these composites. Additionally, the composite could be tailored to be multi-use, such that upon degradation, the resulting products could be used as part of a zeoponic substrate (artificial soil) for growing plants. Such a material would be beneficial for long-duration space missions, terraforming, or in other agricultural applications. The research presented in this dissertation focuses on developing phosphate glass for use as the fiber reinforcement for such a composite. Due to the under-utilization of phosphate systems, there is a lack of thermodynamic data on these systems. The modified associate species method of phase diagram calculation was used in an attempt to gain more information about the desired system, as it is a good predictor of the phase relations in oxide melts, slags, and glasses and requires less data than other methods. Further research into the thermodynamic properties of phosphates is still needed to develop accurate phase diagrams and melting temperatures for this system. Seventeen glass formulations were developed and melted. Six of these formulations were chosen for dissolution testing. Of these six, Glass 17 was chosen for intensive testing and characterization. This glass was tested in water, hydrochloric acid solutions, and citric acid solutions. The weight loss was measured and ICP-OES was performed on the leachate solution. Scanning electron microscopy (SEM) and X-ray diffraction were performed on the tested specimens. Shrinking-core models were fit to the dissolution data. Fibers were drawn from the glass and characterized using SEM. The data shows that this glass is not dissolving congruently, as is expected of phosphate glasses. Instead, selective leaching is occurring, leading to the development of a non-protective surface layer during dissolution.

Towards increased waste loading in high level waste glasses: Developing a better understanding of crystallization behavior

DOE PAGES

Marra, James C.; Kim, Dong -Sang

2014-12-18

A number of waste components in US defense high level radioactive wastes (HLW) have proven challenging for current Joule heated ceramic melter (JCHM) operations and have limited the ability to increase waste loadings beyond already realized levels. Many of these ''troublesome'' waste species cause crystallization in the glass melt that can negatively impact product quality or have a deleterious effect on melter processing. Thus, recent efforts at US Department of Energy laboratories have focused on understanding crystallization behavior within HLW glass melts and investigating approaches to mitigate the impacts of crystallization so that increases in waste loading can be realized.more » Advanced glass formulations have been developed to highlight the unique benefits of next-generation melter technologies such as the Cold Crucible Induction Melter (CCIM). Crystal-tolerant HLW glasses have been investigated to allow sparingly soluble components such as chromium to crystallize in the melter but pass out of the melter before accumulating. The Hanford site AZ-101 tank waste composition represents a waste group that is waste loading limited primarily due to high concentrations of Fe 2O 3 (with higher Al 2O 3). Systematic glass formulation development utilizing slightly higher process temperatures and higher tolerance to spinel crystals demonstrated that an increase in waste loading of more than 20% could be achieved for this waste composition, and by extension higher loadings for wastes in the same group.« less

Stability of total nutrient admixtures with lipid injectable emulsions in glass versus plastic packaging.

PubMed

Driscoll, David F; Silvestri, Anthony P; Bistrian, Bruce R; Mikrut, Bernard A

2007-02-15

The physical stability of two emulsions compounded as part of a total nutrient admixture (TNA) was studied in lipids packaged in either glass or plastic containers. Five weight-based adult TNA formulations that were designed to meet the full nutritional needs of adults with body weights between 40 and 80 kg were studied. Triplicate preparations of each TNA were assessed over 30 hours at room temperature by applying currently proposed United States Pharmacopeia (USP) criteria for mean droplet diameter, large-diameter tail, and globule-size distribution (GSD) for lipid injectable emulsions. In accordance with conditions set forth in USP chapter 729, the higher levels of volume-weighted percent of fat exceeding 5 microm (PFAT(5)) should not exceed 0.05% of the total lipid concentration. Significant differences were noted among TNA admixtures based on whether the lipid emulsion product was manufactured in glass or plastic. The plastic-contained TNAs failed the proposed USP methods for large-diameter fat globules in all formulations from the outset, and 60% had significant growth in large-diameter fat globules over time. In contrast, glass-contained TNAs were stable throughout and in all cases would have passed proposed USP limits. Certain lipid injectable emulsions packaged in plastic containers have baseline abnormal GSD profiles compared with those packaged in glass containers. When used to compound TNAs, the abnormal profile worsens and produces less stable TNAs than those compounded with lipid injectable emulsions packaged in glass containers.

World first in high level waste vitrification - A review of French vitrification industrial achievements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brueziere, J.; Chauvin, E.; Piroux, J.C.

2013-07-01

AREVA has more than 30 years experience in operating industrial HLW (High Level radioactive Waste) vitrification facilities (AVM - Marcoule Vitrification Facility, R7 and T7 facilities). This vitrification technology was based on borosilicate glasses and induction-heating. AVM was the world's first industrial HLW vitrification facility to operate in-line with a reprocessing plant. The glass formulation was adapted to commercial Light Water Reactor fission products solutions, including alkaline liquid waste concentrates as well as platinoid-rich clarification fines. The R7 and T7 facilities were designed on the basis of the industrial experience acquired in the AVM facility. The AVM vitrification process wasmore » implemented at a larger scale in order to operate the R7 and T7 facilities in-line with the UP2 and UP3 reprocessing plants. After more than 30 years of operation, outstanding record of operation has been established by the R7 and T7 facilities. The industrial startup of the CCIM (Cold Crucible Induction Melter) technology with enhanced glass formulation was possible thanks to the close cooperation between CEA and AREVA. CCIM is a water-cooled induction melter in which the glass frit and the waste are melted by direct high frequency induction. This technology allows the handling of highly corrosive solutions and high operating temperatures which permits new glass compositions and a higher glass production capacity. The CCIM technology has been implemented successfully at La Hague plant.« less

Verification Of The Defense Waste Processing Facility's (DWPF) Process Digestion Methods For The Sludge Batch 8 Qualification Sample

DOE Office of Scientific and Technical Information (OSTI.GOV)

Click, D. R.; Edwards, T. B.; Wiedenman, B. J.

2013-03-18

This report contains the results and comparison of data generated from inductively coupled plasma – atomic emission spectroscopy (ICP-AES) analysis of Aqua Regia (AR), Sodium Peroxide/Sodium Hydroxide Fusion Dissolution (PF) and Cold Chem (CC) method digestions and Cold Vapor Atomic Absorption analysis of Hg digestions from the DWPF Hg digestion method of Sludge Batch 8 (SB8) Sludge Receipt and Adjustment Tank (SRAT) Receipt and SB8 SRAT Product samples. The SB8 SRAT Receipt and SB8 SRAT Product samples were prepared in the SRNL Shielded Cells, and the SRAT Receipt material is representative of the sludge that constitutes the SB8 Batch ormore » qualification composition. This is the sludge in Tank 51 that is to be transferred into Tank 40, which will contain the heel of Sludge Batch 7b (SB7b), to form the SB8 Blend composition.« less

Antifoam Degradation Products in Off Gas and Condensate of Sludge Batch 9 Simulant Nitric-Formic Flowsheet Testing for the Defense Waste Processing Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, T.

Ten chemical processing cell (CPC) experiments were performed using simulant to evaluate Sludge Batch 9 for sludge-only and coupled processing using the nitric-formic flowsheet in the Defense Waste Processing Facility (DWPF). Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) cycles were performed on eight of the ten. The other two were SRAT cycles only. Samples of the condensate, sludge, and off gas were taken to monitor the chemistry of the CPC experiments. The Savannah River National Laboratory (SRNL) has previously shown antifoam decomposes to form flammable organic products, (hexamethyldisiloxane (HMDSO), trimethylsilanol (TMS), and propanal), that are presentmore » in the vapor phase and condensate of the CPC vessels. To minimize antifoam degradation product formation, a new antifoam addition strategy was implemented at SRNL and DWPF to add antifoam undiluted.« less

Leaching of plutonium from a radioactive waste glass by eight groundwaters from the western United States

USGS Publications Warehouse

Rees, T.F.; Cleveland, J.M.; Nash, K.L.

1985-01-01

The leachability of a radioactive waste glass formulated to Battelle Pacific Northwest Laboratory specification 80-270 has been studied using eight actual groundwaters with a range of chemical compositions as leachants. Waters collected from the Grande Ronde Basalt (Washington State) and from alluvial deposits in the Hualapai Valley (Arizona) were the most effective at removing plutonium from this glass. Leaching was shown to be incongruent; plutonium was removed from the glass more slowly than the overall glass matrix. The results of these experiments indicate the need to study the leachability of actual waste forms using the actual projected groundwaters that are most likely to come into contact with the waste should a radioactive waste repository be breached.

EFFECTS OF TRITIUM GAS EXPOSURE ON EPDM ELASTOMER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, E.

2009-12-11

Samples of four formulations of ethylene-propylene diene monomer (EPDM) elastomer were exposed to initially pure tritium gas at one atmosphere and ambient temperature for various times up to about 420 days in closed containers. Two formulations were carbon-black-filled commercial formulations, and two were the equivalent formulations without filler synthesized for this work. Tritium effects on the samples were characterized by measuring the sample volume, mass, flexibility, and dynamic mechanical properties and by noting changes in appearance. The glass transition temperature was determined by analysis of the dynamic mechanical properties. The glass transition temperature increased significantly with tritium exposure, and themore » unfilled formulations ceased to behave as elastomers after the longest tritium exposure. The filled formulations were more resistant to tritium exposure. Tritium exposure made all samples significantly stiffer and therefore much less able to form a reliable seal when employed as O-rings. No consistent change of volume or density was observed; there was a systematic lowering of sample mass with tritium exposure. In addition, the significant radiolytic production of gas, mainly protium (H{sub 2}) and HT, by the samples when exposed to tritium was characterized by measuring total pressure in the container at the end of each exposure and by mass spectroscopy of a gas sample at the end of each exposure. The total pressure in the containers more than doubled after {approx}420 days tritium exposure.« less

Long-Term Viscoelastic Response of E-glass/Bismaleimide Composite in Seawater Environment

NASA Astrophysics Data System (ADS)

Yian, Zhao; Zhiying, Wang; Keey, Seah Leong; Boay, Chai Gin

2015-12-01

The effect of seawater absorption on the long-term viscoelastic response of E-glass/BMI composite is presented in this paper. The diffusion of seawater into the composite shows a two-stage behavior, dominated by Fickian diffusion initially and followed by polymeric relaxation. The Glass transition temperature (Tg) of the composite with seawater absorption is considerably lowered due to the plasticization effect. However the effect of water absorption at 50 °C is found to be reversible after drying process. The time-temperature superposition (TTS) was performed based on the results of Dynamic Mechanical Analysis to construct the master curve of storage modulus. The shift factors exhibit Arrhenius behavior when temperature is well below Tg and Vogel-Fulcher-Tammann (VFT) like behavior when temperature gets close to glass transition region. As a result, a semi-empirical formulation is proposed to account for the seawater absorption effect in predicting long-term viscoelastic response of BMI composites based on temperature dependent storage modulus and TTS. The predicted master curves show that the degradation of storage modulus accelerates with both seawater exposure and increasing temperature. The proposed formulation can be applied to predict the long-term durability of any thermorheologically simple composite materials in seawater environment.

EFFECTS OF GAMMA IRRADIATION ON EPDM ELASTOMERS (REVISION 1)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, E.

Two formulations of EPDM elastomer, one substituting a UV stabilizer for the normal antioxidant in this polymer, and the other the normal formulation, were synthesized and samples of each were exposed to gamma irradiation in initially pure deuterium gas to compare their radiation stability. Stainless steel containers having rupture disks were designed for this task. After 130 MRad dose of cobalt-60 radiation in the SRNL Gamma Irradiation Facility, a significant amount of gas was created by radiolysis; however the composition indicated by mass spectroscopy indicated an unexpected increase in the total amount deuterium in both formulations. The irradiated samples retainedmore » their ductility in a bend test. No change of sample weight, dimensions, or density was observed. No change of the glass transition temperature as measured by dynamic mechanical analysis was observed, and most of the other dynamic mechanical properties remained unchanged. There appeared to be an increase in the storage modulus of the irradiated samples containing the UV stabilizer above the glass transition, which may indicate hardening of the material by radiation damage. Revision 1 adds a comparison with results of a study of tritium exposed EPDM. The amount of gas produced by the gamma irradiation was found to be equivalent to about 280 days exposure to initially pure tritium gas at one atmosphere. The glass transition temperature of the tritium exposed EPDM rose about 10°C. over 280 days, while no glass transition temperature change was observed for gamma irradiated EPDM. This means that gamma irradiation in deuterium cannot be used as a surrogate for tritium exposure.« less

DEVELOPMENT OF REMOTE HANFORD CONNECTOR GASKET REPLACEMENT TOOLING FOR DWPF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krementz, D.; Coughlin, Jeffrey

2009-05-05

The Defense Waste Processing Facility (DWPF) requested the Savannah River National Laboratory (SRNL) to develop tooling and equipment to remotely replace gaskets in mechanical Hanford connectors to reduce personnel radiation exposure as compared to the current hands-on method. It is also expected that radiation levels will continually increase with future waste streams. The equipment is operated in the Remote Equipment Decontamination Cell (REDC), which is equipped with compressed air, two master-slave manipulators (MSM's) and an electro-mechanical manipulator (EMM) arm for operation of the remote tools. The REDC does not provide access to electrical power, so the equipment must be manuallymore » or pneumatically operated. The MSM's have a load limit at full extension of ten pounds, which limited the weight of the installation tool. In order to remotely replace Hanford connector gaskets several operations must be performed remotely, these include: removal of the spent gasket and retaining ring (retaining ring is also called snap ring), loading the new snap ring and gasket into the installation tool and installation of the new gasket into the Hanford connector. SRNL developed and tested tools that successfully perform all of the necessary tasks. Removal of snap rings from horizontal and vertical connectors is performed by separate air actuated retaining ring removal tools and is manipulated in the cell by the MSM. In order install a new gasket, the snap ring loader is used to load a new snap ring into a groove in the gasket installation tool. A new gasket is placed on the installation tool and retained by custom springs. An MSM lifts the installation tool and presses the mounted gasket against the connector block. Once the installation tool is in position, the gasket and snap ring are installed onto the connector by pneumatic actuation. All of the tools are located on a custom work table with a pneumatic valve station that directs compressed air to the desired tool and vents the tools as needed. Extensive testing of tooling operation was performed in the DWPF manipulator repair shop. This testing allowed the operators to gain confidence before the equipment was exposed to radioactive contamination. The testing also led to multiple design improvements. On July 17 and 29, 2008 the Remote Gasket Replacement Tooling was successfully demonstrated in the REDC at the DWPF of The Savannah River Site.« less

RESULTS OF THE FY09 ENHANCED DOE HIGH LEVEL WASTE MELTER THROUGHPUT STUDIES AT SRNL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, F.; Edwards, T.

2010-06-23

High-level waste (HLW) throughput (i.e., the amount of waste processed per unit time) is a function of two critical parameters: waste loading (WL) and melt rate. For the Waste Treatment and Immobilization Plant (WTP) at the Hanford Site and the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS), increasing HLW throughput would significantly reduce the overall mission life cycle costs for the Department of Energy (DOE). The objective of this task is to develop data, assess property models, and refine or develop the necessary models to support increased WL of HLW at SRS. It is a continuationmore » of the studies initiated in FY07, but is under the specific guidance of a Task Change Request (TCR)/Work Authorization received from DOE headquarters (Project Number RV071301). Using the data generated in FY07, FY08 and historical data, two test matrices (60 glasses total) were developed at the Savannah River National Laboratory (SRNL) in order to generate data in broader compositional regions. These glasses were fabricated and characterized using chemical composition analysis, X-ray Diffraction (XRD), viscosity, liquidus temperature (TL) measurement and durability as defined by the Product Consistency Test (PCT). The results of this study are summarized below: (1) In general, the current durability model predicts the durabilities of higher waste loading glasses quite well. A few of the glasses exhibited poorer durability than predicted. (2) Some of the glasses exhibited anomalous behavior with respect to durability (normalized leachate for boron (NL [B])). The quenched samples of FY09EM21-02, -07 and -21 contained no nepheline or other wasteform affecting crystals, but have unacceptable NL [B] values (> 10 g/L). The ccc sample of FY09EM21-07 has a NL [B] value that is more than one half the value of the quenched sample. These glasses also have lower concentrations of Al{sub 2}O{sub 3} and SiO{sub 2}. (3) Five of the ccc samples (EM-13, -14, -15, -29 and -30) completely crystallized with both magnetite and nepheline, and still had extremely low NL [B] values. These particular glasses have more CaO present than any of the other glasses in the matrix. It appears that while all of the glasses contain nepheline, the NL [B] values decrease as the CaO concentration increases from 2.3 wt% to 4.3 wt%. A different form of nepheline may be created at higher concentrations of CaO that does not significantly reduce glass durability. (4) The T{sub L} model appears to be under-predicting the measured values of higher waste loading glasses. Trends in T{sub L} with composition are not evident in the data from these studies. (5) A small number of glasses in the FY09 matrix have measured viscosities that are much lower than the viscosity range over which the current model was developed. The decrease in viscosity is due to a higher concentration of non-bridging oxygens (NBO). A high iron concentration is the cause of the increase in NBO. Durability, viscosity and T{sub L} data collected during FY07 and FY09 that specifically targeted higher waste loading glasses was compiled and assessed. It appears that additional data may be required to expand the coverage of the T{sub L} and viscosity models for higher waste loading glasses. In general, the compositional regions of the higher waste loading glasses are very different than those used to develop these models. On the other hand, the current durability model seems to be applicable to the new data. At this time, there is no evidence to modify this model; however additional experimental studies should be conducted to determine the cause of the anomalous durability data.« less

IgG1 adsorption to siliconized glass vials-influence of pH, ionic strength, and nonionic surfactants.

PubMed

Höger, Kerstin; Mathes, Johannes; Frieß, Wolfgang

2015-01-01

In this study, the adsorption of an IgG1 antibody to siliconized vials was investigated with focus on the formulation parameters pH, ionic strength, and nonionic surfactants. Electrophoretic mobility measurements were performed to investigate the charge characteristics of protein and siliconized glass particles at different pH values. Calculation of the electrokinetic charge density allowed further insight into the energetic conditions in the protein-sorbent interface. Maximum adsorption of IgG1 was found at acidic pH values and could be correlated with energetically favorable minimal ion incorporation into the interface. The importance of electrostatic interactions for IgG1 adsorption at acidic pH values was also confirmed by the efficient adsorption reduction at decreased solution ionic strength. A second adsorption maximum around the pI of the protein was assigned to hydrophobic interactions with the siliconized surface. Addition of the nonionic surfactants poloxamer 188 or polysorbate 80 resulted in almost complete suppression of adsorption at pH 7.2, and a strong but less efficient effect at pH 4 on siliconized glass vials. This adsorption suppression was much less pronounced on borosilicate glass vials. From these results, it can be concluded that electrostatic interactions contribute substantially to IgG1 adsorption to siliconized glass vials especially at acidic formulation pH. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Development of Room Temperature Stable Formulation of Formoterol Fumarate/Beclomethasone HFA pMDI

PubMed Central

Purohit, D.; Trehan, A.; Arora, V.

2009-01-01

The primary aim of present investigation was to develop and formulate room temperature stable formulation of formoterol fumarate and beclomethasone dipropionate with extra fine part size of hydrofluoroalkane pressurized metered dose inhalers. Particle size distribution of hydrofluoroalkane pressurized metered dose inhalers was evaluated using Twin Stage Glass Impinger and Anderson Cascade Impactor. A tetrafluoroethane and/or heptafluoropropane were evaluated for preparation of hydrofluoroalkane pressurized metered dose inhalers. The fine particle fractions delivered from hydrofluoroalkane propellant suspension pressurized metered dose inhalers can be predicted on the basis of formulation parameters and is dependent of metering chamber of valve and orifice size of actuators. The results presented in investigation showed the importance of formulation excipients with formulation of pressurized metered dose inhalers viz, canister, valve and actuators used in formulations.

IMPACT OF NOBLE METALS AND MERCURY ON HYDROGEN GENERATION DURING HIGH LEVEL WASTE PRETREATMENT AT THE SAVANNAH RIVER SITE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, M; Tommy Edwards, T; David Koopman, D

2009-03-03

The Defense Waste Processing Facility (DWPF) at the Savannah River Site vitrifies radioactive High Level Waste (HLW) for repository internment. The process consists of three major steps: waste pretreatment, vitrification, and canister decontamination/sealing. HLW consists of insoluble metal hydroxides (primarily iron, aluminum, calcium, magnesium, manganese, and uranium) and soluble sodium salts (carbonate, hydroxide, nitrite, nitrate, and sulfate). The pretreatment process in the Chemical Processing Cell (CPC) consists of two process tanks, the Sludge Receipt and Adjustment Tank (SRAT) and the Slurry Mix Evaporator (SME) as well as a melter feed tank. During SRAT processing, nitric and formic acids are addedmore » to the sludge to lower pH, destroy nitrite and carbonate ions, and reduce mercury and manganese. During the SME cycle, glass formers are added, and the batch is concentrated to the final solids target prior to vitrification. During these processes, hydrogen can be produced by catalytic decomposition of excess formic acid. The waste contains silver, palladium, rhodium, ruthenium, and mercury, but silver and palladium have been shown to be insignificant factors in catalytic hydrogen generation during the DWPF process. A full factorial experimental design was developed to ensure that the existence of statistically significant two-way interactions could be determined without confounding of the main effects with the two-way interaction effects. Rh ranged from 0.0026-0.013% and Ru ranged from 0.010-0.050% in the dried sludge solids, while initial Hg ranged from 0.5-2.5 wt%, as shown in Table 1. The nominal matrix design consisted of twelve SRAT cycles. Testing included: a three factor (Rh, Ru, and Hg) study at two levels per factor (eight runs), three duplicate midpoint runs, and one additional replicate run to assess reproducibility away from the midpoint. Midpoint testing was used to identify potential quadratic effects from the three factors. A single sludge simulant was used for all tests and was spiked with the required amount of noble metals immediately prior to performing the test. Acid addition was kept effectively constant except to compensate for variations in the starting mercury concentration. SME cycles were also performed during six of the tests.« less

Optimal glass-ceramic structures: Components of giant mirror telescopes

NASA Technical Reports Server (NTRS)

Eschenauer, Hans A.

1990-01-01

Detailed investigations are carried out on optimal glass-ceramic mirror structures of terrestrial space technology (optical telescopes). In order to find an optimum design, a nonlinear multi-criteria optimization problem is formulated. 'Minimum deformation' at 'minimum weight' are selected as contradictory objectives, and a set of further constraints (quilting effect, optical faults etc.) is defined and included. A special result of the investigations is described.

On the structure and radiation chemistry of iron phosphate glasses: New insights from electron spin resonance, Mössbauer, and evolved-gas mass spectroscopy

NASA Astrophysics Data System (ADS)

Griscom, D. L.; Merzbacher, C. I.; Bibler, N. E.; Imagawa, H.; Uchiyama, S.; Namiki, A.; Marasinghe, G. K.; Mesko, M.; Karabulut, M.

1998-05-01

Several vitreous forms for immobilization of plutonium and/or high-level nuclear wastes have been surveyed by electron spin resonance (ESR) to gain insights into their atomic-scale structures and to look for signs of radiolytic decomposition resulting from exposures to γ-ray doses of 30 MGy. While preliminary results are reported for Defense Waste Processing Facility (DWPF) borosilicate compositions and an experimental lanthanum-silicate glass, this paper focusses primarily on a class of glasses containing 40-75 mol% P 2O 5 and up to 40 mol% Fe 2O 3. Each of the six diverse compositions investigated displayed characteristic ESR signals (not resembling those of the iron-containing phosphorus-free glasses) comprising combinations of an extremely broad "X resonance" and a narrow "Z resonance", both centered near g=2.00 and both displaying nearly perfect Lorentzian line shapes (peak-to-peak derivative widths ˜300-600 mT and ˜30 mT, respectively, at 300 K). The X-resonance intensities in the air-melted glasses correlated linearly with Fe:P ratio up to [Fe 2O 3]/[P 2O 5] ≈ 0.6, where intensity values ˜1 spin/phosphorus were reached. Mössbauer studies showed that the [Fe 3+]/[Fe] tot ratio could be varied from 0.82 to 0.49 by raising the melting temperature in air from 1150°C to 1450°C and/or by employing mildly reducing atmospheres. The combined X + Z-resonance intensities were reduced to zero for [Fe 3+]/[Fe] tot less than ˜0.6, leaving only a much weaker spectrum attributable to Fe 3+ ions. The X and Z ESR signals of the iron phosphate glasses resemble nothing else in the literature except the correspondingly denoted signals in an iron-free amorphous peroxyborate (APB) preparation. The X and Z resonances in the latter are deemed to arise from superoxide ions (O 2-) in the borate network and in a separated Na 2O 2 phase, respectively. An asymmetric Z resonance signal attributable to interstitial O 2- species was a radiation-induced manifestation in phosphate glass of composition 50P 2O 5-20Fe 2O 3-23Li 2O-7CeO 2. Irradiated and unirradiated samples of this same glass were studied by ESR isochronal annealing and differential thermal analysis, revealing a one-for-one conversion of X to Z upon partial crystallization near 670°C and a Z → X reconversion upon partial remelting near 970°C. Heating to 1070°C in dry Ar resulted in a weight loss of ˜5 wt%, while quadrupole mass spectrometry (QMS) during ramped heating to 1550°C at a pressure of 10 -5 Pa revealed the evolution of O 2 molecules with (radiation sensitive) ion-current peaks near 1170°C and 1350-1400°C. To account for the totality of these and other results, it is suggested that air-melted iron phosphate glasses may contain macroscopic numbers of superoxide ions as an intrinsic chemical feature of their as-quenched structures. A specific four-connected phosphorus-oxygen glass network incorporating O 2- ions is proposed.

Structure and properties of barium tin boro-phosphate glass systems with very low photoelastic constant

NASA Astrophysics Data System (ADS)

Itadani, M.; Tricot, G.; Doumert, B.; Takebe, H.; Saitoh, A.

2017-08-01

Glasses in the BaO-SnO-P2O5-B2O3 system were prepared and evaluated in order to formulate preform glasses suitable for the fabrication of fiber cores with a very low photoelastic constant. A first glass system (I: xBaO-(60-x)SnO-40P2O5) was designed with a constant P2O5 content and various BaO contents (0-40 mol. %). Introduction of 3 mol. % of B2O3 to enhance the glass stability leads to the second glass system (II: x'BaO-(57-x')SnO-40P2O5-3B2O3) with 33-38 mol. % BaO. The structure of both systems was investigated by 1D/2D magic-angle spinning nuclear magnetic resonance, Raman, and Fourier transform infrared spectroscopic techniques. 31P NMR showed the presence of Q2 and Q1 units in the first system and correlation 11B/31P NMR indicated that boron enters into the network as B(OP)4 structural units. The photoelastic constant was determined and the stability of the best formulations as well as their refractive index dispersion was established. The drawing temperature and isothermal heating time (without crystal precipitation) parameters were also accurately measured by using experimental time-temperature-transition. Considering that the refractive indices of the core and the cladding materials must match, detailed core and cladding compositions for a fiber enabling single-mode waveguide transmission were proposed.

Glass binder development for a glass-bonded sodalite ceramic waste form

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riley, Brian J.; Vienna, John D.; Frank, Steven M.

This paper discusses work to develop Na2O-B2O3-SiO2 glass binders for immobilizing LiCl-KCl eutectic salt waste in a glass-bonded sodalite waste form following electrochemical reprocessing of used metallic nuclear fuel. Here, five new glasses with high Na2O contents were designed to generate waste forms having higher sodalite contents and fewer stress fractures. The structural, mechanical, and thermal properties of the new glasses were measured using variety of analytical techniques. The glasses were then used to produce ceramic waste forms with surrogate salt waste. The materials made using the glasses developed during this study were formulated to generate more sodalite than materialsmore » made with previous baseline glasses used. The coefficients of thermal expansion for the glass phase in the glass-bonded sodalite waste forms made with the new binder glasses were closer to the sodalite phase in the critical temperature region near and below the glass transition temperature. These improvements should result in lower probability of cracking in the full-scale monolithic ceramic waste form, leading to better long-term chemical durability. Additionally, a model generated during this study for predicting softening temperature of silicate binder glasses is presented.« less

Thermally stable laminating resins

NASA Technical Reports Server (NTRS)

Jones, R. J.; Vaughan, R. W.; Burns, E. A.

1972-01-01

Improved thermally stable laminating resins were developed based on the addition-type pyrolytic polymerization. Detailed monomer and polymer synthesis and characterization studies identified formulations which facilitate press molding processing and autoclave fabrication of glass and graphite fiber reinforced composites. A specific resin formulation, termed P10P was utilized to prepare a Courtaulds HMS reinforced simulated airfoil demonstration part by an autoclave molding process.

Phase 2 Report--Mercury Behavior In The Defense Waste Processing Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C.; Fellinger, T.

2016-07-27

The purpose of this report is to provide a summary of the DWPF processing history in regards to mercury, document the mercury results obtained on the product and condensate samples, and provide further recommendations based on the data obtained.

Amorphization within the tablet: Using microwave irradiation to form a glass solution in situ.

PubMed

Doreth, Maria; Hussein, Murtadha Abdul; Priemel, Petra A; Grohganz, Holger; Holm, René; Lopez de Diego, Heidi; Rades, Thomas; Löbmann, Korbinian

2017-03-15

In situ amorphization is a concept that allows to amorphize a given drug in its final dosage form right before administration. Hence, this approach can potentially be used to circumvent recrystallization issues that other amorphous formulation approaches are facing during storage. In this study, the feasibility of microwave irradiation to prepare amorphous solid dispersions (glass solutions) in situ was investigated. Indomethacin (IND) and polyvinylpyrrolidone K12 (PVP) were tableted at a 1:2 (w/w) ratio. In order to study the influence of moisture content and energy input on the degree of amorphization, tablet formulations were stored at different relative humidity (32, 43 and 54% RH) and subsequently microwaved using nine different power-time combinations up to a maximum energy input of 90kJ. XRPD results showed that up to 80% (w/w) of IND could be amorphized within the tablet. mDSC measurements revealed that with increasing microwaving power and time, the fractions of crystalline IND and amorphous PVP reduced, whereas the amount of in situ formed IND-PVP glass solution increased. Intrinsic dissolution showed that the dissolution rate of the microwaved solid dispersion was similar to that of a quench cooled, fully amorphous glass solution even though the microwaved samples contained residual crystalline IND. Copyright © 2017 Elsevier B.V. All rights reserved.

Understanding the glass-forming ability of active pharmaceutical ingredients for designing supersaturating dosage forms.

PubMed

Kawakami, Kohsaku; Usui, Toshinori; Hattori, Mitsunari

2012-09-01

Amorphous solid dispersions have great potential for enhancing oral absorption of poorly soluble drugs. Crystallization behavior during storage and after exposure to aqueous media must be examined in detail for designing stable and effective amorphous formulations, and it is significantly affected by the intrinsic properties of an amorphous drug. Many attempts have been made to correlate various thermodynamic parameters of pharmaceutical glasses with their crystallization behavior; however, variations in model drugs that could be used for such investigation has been limited because the amorphous characteristics of drugs possessing a high crystallization tendency are difficult to evaluate. In this study, high-speed differential scanning calorimetry, which could inhibit their crystallization using high cooling rates up to 2000°C/s, was employed for assessing such drugs. The thermodynamic parameters of the glasses, including glass transition temperature (T(g)) and fragility, were obtained to show that their crystallization tendency cannot be explained simply by the parameters, although there have been general thought that fragility may be correlated with crystallization tendency. Also investigated was correlation between the thermodynamic parameters and crystallization tendency upon contact with water, which influences in vivo efficacy of amorphous formulations. T(g) was correlated well with the crystallization tendency upon contact with water. Copyright © 2012 Wiley Periodicals, Inc.

Synthesis of N-vinylpyrrolidone modified acrylic acid copolymer in supercritical fluids and its application in dental glass-ionomer cements.

PubMed

Moshaverinia, Alireza; Roohpour, Nima; Billington, Richard W; Darr, Jawwad A; Rehman, Ihtesham U

2008-07-01

Compressed fluids such as supercritical CO(2) offer marvellous opportunities for the synthesis of polymers, particularly in applications in medicine and dentistry. It has several advantages in comparison to conventional polymerisation solvents, such as enhanced kinetics and simplified solvent removal process. In this study, poly(acrylic acid-co-itaconic acid-co-N-vinylpyrrolidone) (PAA-IA-NVP), a modified glass-ionomer polymer, was synthesised in supercritical CO(2) (sc-CO(2)) and methanol as a co-solvent. The synthesised polymer was characterized by (1)H-NMR, Raman and FT-IR spectroscopy and viscometry. The molecular weight of the final product was also measured using static light scattering method. The synthesised polymers were subsequently used in several glass ionomer cement formulations (Fuji II commercial GIC) in which mechanical strength (compressive strength (CS), diametral tensile strength (DTS) and biaxial flexural strength (BFS)) and handling properties (working and setting time) of the resulting cements were evaluated. The polymerisation reaction in sc-CO(2)/methanol was significantly faster than the corresponding polymerisation reaction in water and the purification procedures were simpler for the former. Furthermore, glass ionomer cement samples made from the terpolymer prepared in sc-CO(2)/methanol exhibited higher CS and DTS and comparable BFS compared to the same polymer synthesised in water. The working properties of glass ionomer formulations made in sc-CO(2)/methanol were comparable and in selected cases better than the values of those made from polymers synthesised in water.

Development and evaluation of elastomeric materials for geothermal applications

NASA Technical Reports Server (NTRS)

Mueller, W. A.; Kalfayan, S. H.; Reilly, W. W.; Ingham, J. D.

1978-01-01

A material for a casing packer for service for 24 hours in a geothermal environment was developed by synthesis of new elastomers and formulation of available materials. Formulation included use of commercial elastomer gumstocks and also crosslinking of plastic (high Tg) materials. Fibrous reinforcement of fluorocarbon rubbers was emphasized. Organic fiber reinforcement did not increase hot properties significantly. Glass fiber reinforcement gave significant increase in tensile properties. Elongation was reduced, and the glass-reinforced composition examined so far did not hold up well in the geothermal environment. Colloidal asbestos fibers were also investigated. A few experiments with polyphenyl ether gave material with low tensile and high compression set. Available high styrene SBR compositions were studied. Work to date suggests that new synthetic polymers will be required for service in geothermal environments.

A Review of Glass-Ionomer Cements for Clinical Dentistry

PubMed Central

Sidhu, Sharanbir K.; Nicholson, John W.

2016-01-01

This article is an updated review of the published literature on glass-ionomer cements and covers their structure, properties and clinical uses within dentistry, with an emphasis on findings from the last five years or so. Glass-ionomers are shown to set by an acid-base reaction within 2–3 min and to form hard, reasonably strong materials with acceptable appearance. They release fluoride and are bioactive, so that they gradually develop a strong, durable interfacial ion-exchange layer at the interface with the tooth, which is responsible for their adhesion. Modified forms of glass-ionomers, namely resin-modified glass-ionomers and glass carbomer, are also described and their properties and applications covered. Physical properties of the resin-modified glass-ionomers are shown to be good, and comparable with those of conventional glass-ionomers, but biocompatibility is somewhat compromised by the presence of the resin component, 2 hydroxyethyl methacrylate. Properties of glass carbomer appear to be slightly inferior to those of the best modern conventional glass-ionomers, and there is not yet sufficient information to determine how their bioactivity compares, although they have been formulated to enhance this particular feature. PMID:27367737

A new glass option for parenteral packaging.

PubMed

Schaut, Robert A; Peanasky, John S; DeMartino, Steven E; Schiefelbein, Susan L

2014-01-01

Glass is the ideal material for parenteral packaging because of its chemical durability, hermeticity, strength, cleanliness, and transparency. Alkali borosilicate glasses have been used successfully for a long time, but they do have some issues relating to breakage, delamination, and variation in hydrolytic performance. In this paper, alkali aluminosilicate glasses are introduced as a possible alternative to alkali borosilicate glasses. An example alkali aluminosilicate glass is shown to meet the compendial requirements, and to have similar thermal, optical, and mechanical attributes as the current alkali borosilicate glasses. In addition, the alkali aluminosilicate performed as well or better than the current alkali borosilicates in extractables tests and stability studies, which suggests that it would be suitable for use with the studied liquid product formulation. The physical, mechanical, and optical properties of glass make it an ideal material for packaging injectable drugs and biologics. Alkali borosilicate glasses have been used successfully for a long time for these applications, but there are some issues. In this paper, alkali aluminosilicate glasses are introduced as a possible alternative to alkali borosilicate glasses. An example alkali aluminosilicate glass is shown to meet the requirements for packaging injectable drugs and biologics, and to be suitable for use with a particular liquid drug. © PDA, Inc. 2014.

Characterization of the SRNL-Washed tank 51 sludge batch 9 qualification sample

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pareizs, J. M.

2016-01-01

Savannah River National Laboratory (SRNL) personnel have been requested to qualify the next sludge batch (Sludge Batch 9 – SB9) for processing at the Defense Waste Processing Facility (DWPF). To accomplish this task, Savannah River Remediation (SRR) sent SRNL a 3-L sample of Tank 51H slurry to be characterized, washed, and then used in a lab-scale demonstration of the DWPF flowsheet (after combining with Tank 40H sludge). SRNL has washed the Tank 51H sample per the Tank Farm washing strategy as of October 20, 2015. A part of the qualification process is extensive radionuclide and chemical characterization of the SRNL-washedmore » Tank 51H slurry. This report documents the chemical characterization of the washed slurry; radiological characterization is in progress and will be documented in a separate report. The analytical results of this characterization are comparable to the Tank Farm projections. Therefore, it is recommended that SRNL use this washed slurry for the ongoing SB9 qualification activities.« less

Measurement of chalcogenide glass optical dispersion using a mid-infrared prism coupler

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiao, Hong; Anheier, Norman C.; Musgraves, Jonathan D.

2011-05-01

Physical properties of chalcogenide glass, including broadband infrared transparency, high refractive index, low glass transition temperature, and nonlinear properties, make them attractive candidates for advanced mid-infrared (3 to 12 {micro}m) optical designs. Efforts focused at developing new chalcogenide glass formulations and processing methods require rapid quantitative evaluation of their optical contents to guide the materials research. However, characterization of important optical parameters such as optical dispersion remains a slow and costly process, generally with limited accuracy. The recent development of a prism coupler at the Pacific Northwest National Laboratory (PNNL) now enables rapid, high precision measurement of refractive indices atmore » discrete wavelengths from the visible to the mid-infrared. Optical dispersion data of several chalcogenide glass families were collected using this method. Variations in the optical dispersion were correlated to glass composition and compared against measurements using other methods. While this work has been focused on facilitating chalcogenide glass synthesis, mid-infrared prism coupler analysis has broader applications to other mid-infrared optical material development efforts, including oxide glasses and crystalline materials.« less

Application of a computational glass model to the shock response of soda-lime glass

DOE PAGES

Gorfain, Joshua E.; Key, Christopher T.; Alexander, C. Scott

2016-04-20

This article details the implementation and application of the glass-specific computational constitutive model by Holmquist and Johnson [1] to simulate the dynamic response of soda-lime glass under high rate and high pressure shock conditions. The predictive capabilities of this model are assessed through comparison of experimental data with numerical results from computations using the CTH shock physics code. The formulation of this glass model is reviewed in the context of its implementation within CTH. Using a variety of experimental data compiled from the open literature, a complete parameterization of the model describing the observed behavior of soda-lime glass is developed.more » Simulation results using the calibrated soda-lime glass model are compared to flyer plate and Taylor rod impact experimental data covering a range of impact and failure conditions spanning an order of magnitude in velocity and pressure. In conclusion, the complex behavior observed in the experimental testing is captured well in the computations, demonstrating the capability of the glass model within CTH.« less

Microfluidic routing of aqueous and organic flows at high pressures: fabrication and characterization of integrated polymer microvalve elements.

PubMed

Kirby, Brian J; Reichmuth, David S; Renzi, Ronald F; Shepodd, Timothy J; Wiedenman, Boyd J

2005-02-01

This paper presents the first systematic engineering study of the impact of chemical formulation and surface functionalization on the performace of free-standing microfluidic polymer elements used for high-pressure fluid control in glass microsystems. System design, chemical wet-etch processes, and laser-induced polymerization techniques are described, and parametric studies illustrate the effects of polymer formulation, glass surface modification, and geometric constraints on system performance parameters. In particular, this study shows that highly crosslinked and fluorinated polymers can overcome deficiencies in previously-reported microvalve architectures, particularly limited solvent compatibility. Substrate surface modification is shown effective in reducing the friction of the polymer-glass interface and thereby facilitating valve actuation. A microchip one-way valve constructed using this architecture shows a 2 x 10(8) ratio of forward and backward flow rates at 7 MPa. This valve architecture is integrated on chip with minimal dead volumes (70 pl), and should be applicable to systems (including chromatography and chemical synthesis devices) requiring high pressures and solvents of varying polarity.

Stability of pyrimethamine in a liquid dosage formulation stored for three months.

PubMed

Nahata, M C; Morosco, R S; Hipple, T F

1997-12-01

The stability of pyrimethamine in a liquid dosage formulation stored for up to three months was studies. Commercially available 25-mg pyrimethamine tablets were crushed with a mortar and pestle and mixed with a 1:1 mixture of Simple Syrup, NF, and 1% methylcellulose to yield a suspension with a pyrimethamine concentration of 2 mg/mL. The suspension was poured into 10 amber plastic and 10 amber glass prescription bottles; 5 plastic and 5 glass bottles were stored at 4 degrees C, and the remaining bottles were kept at 25 degrees C. Samples were collected at intervals up to 91 days and tested for pyrimethamine concentration by stability-indicating high-performance liquid chromatography. Pyrimethamine remained stable throughout the three-month study period under all conditions. At 4 degrees C, pyrimethamine concentrations remained above 96% of the initial concentration; at 25 degrees C, pyrimethamine concentrations remained above 91%. No substantial changes in pH were observed. Pyrimethamine was stable for at least 91 days in an oral suspension stored in plastic or glass prescription bottles at 4 or 25 degrees C.

Enhanced LAW Glass Correlation - Phase 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muller, Isabelle S.; Matlack, Keith S.; Pegg, Ian L.

About 50 million gallons of high-level mixed waste is currently stored in underground tanks at the United States Department of Energy’s (DOE’s) Hanford site in the State of Washington. The Hanford Tank Waste Treatment and Immobilization Plant (WTP) will provide DOE’s Office of River Protection (ORP) with a means of treating this waste by vitrification for subsequent disposal. The tank waste will be separated into low- and high-activity waste fractions, which will then be vitrified respectively into Immobilized Low Activity Waste (ILAW) and Immobilized High Level Waste (IHLW) products. The ILAW product will be disposed in an engineered facility onmore » the Hanford site while the IHLW product is designed for acceptance into a national deep geological disposal facility for high-level nuclear waste. The ILAW and IHLW products must meet a variety of requirements with respect to protection of the environment before they can be accepted for disposal. Acceptable glass formulations for vitrification of Hanford low activity waste (LAW) must meet a variety of product quality, processability, and waste loading requirements. To this end, The Vitreous State Laboratory (VSL) at The Catholic University of America (CUA) developed and tested a number of glass formulations during Part A, Part B1 and Part B2 of the WTP development program. The testing resulted in the selection of target glass compositions for the processing of eight of the Phase I LAW tanks. The selected glass compositions were tested at the crucible scale to confirm their compliance with ILAW performance requirements. Duramelter 100 (DM100) and LAW Pilot Melter tests were then conducted to demonstrate the viability of these glass compositions for LAW vitrification at high processing rates.« less

Office of River Protection Advanced Low-Activity Waste Glass Research and Development Plan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peeler, David K.; Kim, Dong-Sang; Vienna, John D.

2015-11-01

The U.S. Department of Energy Office of River Protection (ORP) has initiated and leads an integrated Advanced Waste Glass (AWG) program to increase the loading of Hanford tank wastes in glass while meeting melter lifetime expectancies and process, regulatory, and product performance requirements. The integrated ORP program is focused on providing a technical, science-based foundation for making key decisions regarding the successful operation of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) facilities in the context of an optimized River Protection Project (RPP) flowsheet. The fundamental data stemming from this program will support development of advanced glass formulations, keymore » product performance and process control models, and tactical processing strategies to ensure safe and successful operations for both the low-activity waste (LAW) and high-level waste vitrification facilities. These activities will be conducted with the objective of improving the overall RPP mission by enhancing flexibility and reducing cost and schedule. The purpose of this advanced LAW glass research and development plan is to identify the near-term, mid-term, and longer-term research and development activities required to develop and validate advanced LAW glasses, property-composition models and their uncertainties, and an advanced glass algorithm to support WTP facility operations, including both Direct Feed LAW and full pretreatment flowsheets. Data are needed to develop, validate, and implement 1) new glass property-composition models and 2) a new glass formulation algorithm. Hence, this plan integrates specific studies associated with increasing the Na2O and SO3/halide concentrations in glass, because these components will ultimately dictate waste loadings for LAW vitrification. Of equal importance is the development of an efficient and economic strategy for 99Tc management. Specific and detailed studies are being implemented to understand the fate of Tc throughout the WTP flowsheet and the underlying mechanisms that dictate its partitioning between streams within the LAW vitrification facility. These studies are aimed at increasing the single-pass Tc retention in glass and the potential use of high-temperature mineral phases to capture Tc. The Tc-bearing mineral phases would be thermally stable and resistant to Tc release during feed melting reactions or they could serve as alternative waste forms. The LAW glass research and development is focused on reducing the total volume of LAW glass produced and minimizing the impact of (or potentially eliminating) the need for recycle.« less

Development of new EVA formulations for improved performance at NREL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pern, F.J.

1997-02-01

We review in chronological order the research stages and fundamental concepts involved in developing modified and new EVA formulations for improved performance against photo-induced degradation and discoloration. The new NREL EVA formulations use additives totally different from the present commercial formulations (EVA A9918 and EVA 15295). Validation of their long-term photostability and thermostability is presently under way. Together with UV-absorbing glass superstrates, they may offer better success in achieving a more reliable module performance and longer service life without significant EVA discoloration problems, which are commonly experienced with EVA A9918 and, at a lesser rate, EVA 15295. {copyright} {ital 1997more » American Institute of Physics.}« less

Commercial Ion Exchange Resin Vitrification in Borosilicate Glass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cicero-Herman, C.A.; Workman, P.; Poole, K.

1998-05-01

Bench-scale studies were performed to determine the feasibility of vitrification treatment of six resins representative of those used in the commercial nuclear industry. Each resin was successfully immobilized using the same proprietary borosilicate glass formulation. Waste loadings varied from 38 to 70 g of resin/100 g of glass produced depending on the particular resin, with volume reductions of 28 percent to 68 percent. The bench-scale results were used to perform a melter demonstration with one of the resins at the Clemson Environmental Technologies Laboratory (CETL). The resin used was a weakly acidic meth acrylic cation exchange resin. The vitrification processmore » utilized represented a approximately 64 percent volume reduction. Glass characterization, radionuclide retention, offgas analyses, and system compatibility results will be discussed in this paper.« less

Filling of High-Concentration Monoclonal Antibody Formulations into Pre-filled Syringes: Investigating Formulation-Nozzle Interactions To Minimize Nozzle Clogging.

PubMed

Shieu, Wendy; Stauch, Oliver B; Maa, Yuh-Fun

2015-01-01

Syringe filling of high-concentration/viscosity monoclonal antibody formulations is a complex process that is not fully understood. This study, which builds on a previous investigation that used a bench-top syringe filling unit to examine formulation drying at the filling nozzle tip and subsequent nozzle clogging, further explores the impact of formulation-nozzle material interactions on formulation drying and nozzle clogging. Syringe-filling nozzles made of glass, stainless steel, or plastic (polypropylene, silicone, and Teflon®), which represent a full range of materials with hydrophilic and hydrophobic properties as quantified by contact angle measurements, were used to fill liquids of different viscosity, including a high-concentration monoclonal antibody formulation. Compared with hydrophilic nozzles, hydrophobic nozzles offered two unique features that discouraged formulation drying and nozzle clogging: (1) the liquid formulation is more likely to be withdrawn into the hydrophobic nozzle under the same suck-back conditions, and (2) the residual liquid film left on the nozzle wall when using high suck-back settings settles to form a liquid plug away from the hydrophobic nozzle tip. Making the tip of the nozzle hydrophobic (silicone-coating on glass and Teflon-coating stainless steel) could achieve the same suck-back performance as plastic nozzles. This study demonstrated that using hydrophobic nozzles are most effective in reducing the risk of nozzle clogging by drying of high-concentration monoclonal antibody formulation during extended nozzle idle time in a large-scale filling facility and environment. Syringe filling is a well-established manufacturing process and has been implemented by numerous contract manufacturing organizations and biopharmaceutical companies. However, its technical details and associated critical process parameters are rarely published. Information on high-concentration/viscosity formulation filling is particularly lacking. This study is the continuation of a previous investigation with a focus on understanding the impact of nozzle material on the suck-back function of liquid formulations. The findings identified the most critical parameter-nozzle material hydrophobicity-in alleviating formulation drying at the nozzle tip and eventually limiting the occurrence of nozzle clogging during the filling process. The outcomes of this study will benefit scientists and engineers who develop pre-filled syringe products by providing a better understanding of high-concentration formulation filling principles and challenges. © PDA, Inc. 2015.

High temperature electrical conductivity of rigid polyurethane foam

NASA Astrophysics Data System (ADS)

Johnson, R. T., Jr.

1984-03-01

The temperature dependence of the electrical conductivity of three rigid polyurethane foams prepared using different formulations was measured to approx. 320 C. The materials exhibit similar conductivity characteristics, showing a pronounced increase in conductivity with increasing temperature. The insulating characteristics to approx. 200 C are better than that for phenolic materials (glass fabric reinforced), and are similar to those for silicone materials (glass microsphere reinforced). At higher temperatures (500 to 600 C), the phenolics and silicones are better insulators.

Synthesis of a proline-modified acrylic acid copolymer in supercritical CO2 for glass-ionomer dental cement applications.

PubMed

Moshaverinia, Alireza; Roohpour, Nima; Darr, Jawwad A; Rehman, Ihtesham U

2009-06-01

Supercritical (sc-) fluids (such as sc-CO(2)) represent interesting media for the synthesis of polymers in dental and biomedical applications. Sc-CO(2) has several advantages for polymerization reactions in comparison to conventional organic solvents. It has several advantages in comparison to conventional polymerization solvents, such as enhanced kinetics, being less harmful to the environment and simplified solvent removal process. In our previous work, we synthesized poly(acrylic acid-co-itaconic acid-co-N-vinylpyrrolidone) (PAA-IA-NVP) terpolymers in a supercritical CO(2)/methanol mixture for applications in glass-ionomer dental cements. In this study, proline-containing acrylic acid copolymers were synthesized, in a supercritical CO(2) mixture or in water. Subsequently, the synthesized polymers were used in commercially available glass-ionomer cement formulations (Fuji IX commercial GIC). Mechanical strength (compressive strength (CS), diametral tensile strength (DTS) and biaxial flexural strength (BFS)) and handling properties (working and setting time) of the resulting modified cements were evaluated. It was found that the polymerization reaction in an sc-CO(2)/methanol mixture was significantly faster than the corresponding polymerization reaction in water and the purification procedures were simpler for the former. Furthermore, glass-ionomer cement samples made from the terpolymer prepared in sc-CO(2)/methanol exhibited higher CS and DTS and comparable BFS compared to the same polymer synthesized in water. The working properties of glass-ionomer formulations made in sc-CO(2)/methanol were comparable and better than the values of those for polymers synthesized in water.

Fenitrothion: an alternative insecticide for the control of deltamethrin-resistant populations of Triatoma infestans in northern Argentina.

PubMed

Germano, M; Picollo, M I; Spillmann, C; Mougabure-Cueto, G

2014-03-01

Deltamethrin-based campaigns to control Triatoma infestans (Klug) (Hemiptera: Reduviidae) have decreased in success as a result of the development of insecticide resistance. We compared the in vitro effects of the pyrethroid deltamethrin and two doses of the organophosphate fenitrothion, presented on different materials, on T. infestans from La Esperanza, Argentina. Laboratory tests demonstrated a decrease in susceptibility to deltamethrin in the field population [LD50 : 30.32 nanograms per insect (ng/i)] compared with the reference population (LD50 : 0.13 ng/i), giving a high resistance ratio of 233.42. By contrast, similar susceptibility to fenitrothion was assessed in both the field and reference populations (LD50 : 21.65 ng/i and 21.38 ng/i, respectively). The effectiveness of the formulated insecticides varied according to the surfaces to which they were applied. The application of fenitrothion formulations to glass or brick resulted in mortality of 90-100%. The application of fenitrothion formulations to wood or mud caused mortality in the range of 6.7-56.7%. Resistant insects presented low mortality when exposed to the deltamethrin formulation and high mortality when exposed to fenitrothion formulations. Moreover, the insecticides demonstrated residual activity only when applied to glass. The present work demonstrates that fenitrothion is an alternative to pyrethroids for the management of deltamethrin-resistant insects in La Esperanza. However, this effectiveness is not sustained over time. © 2013 The Royal Entomological Society.

Characterization of surface properties of glass vials used as primary packaging material for parenterals.

PubMed

Ditter, Dominique; Mahler, Hanns-Christian; Roehl, Holger; Wahl, Michael; Huwyler, Joerg; Nieto, Alejandra; Allmendinger, Andrea

2018-04-01

The appropriate selection of adequate primary packaging, such as the glass vial, rubber stopper, and crimp cap for parenteral products is of high importance to ensure product stability, microbiological quality (integrity) during storage as well as patient safety. A number of issues can arise when inadequate vial material is chosen, and sole compliance to hydrolytic class I is sometimes not sufficient when choosing a glass vial. Using an appropriate pre-treatment, such as surface modification or coating of the inner vial surface after the vial forming process the glass container quality is often improved and interactions of the formulation with the surface of glass may be minimized. This study aimed to characterize the inner surface of different type I glass vials (Exp33, Exp51, Siliconized, TopLyo™ and Type I plus®) at the nanoscale level. All vials were investigated topographically by colorimetric staining and Scanning Electron Microscopy (SEM). Glass composition of the surface was studied by Time-of-Flight - Secondary Ion Mass Spectrometry (ToF-SIMS) and X-ray Photoelectron Spectroscopy (XPS), and hydrophobicity/hydrophilicity of the inner surface was assessed by dye tests and surface energy measurements. All containers were studied unprocessed, as received from the vendor, i.e. in unwashed and non-depyrogenized condition. Clear differences were found between the different vial types studied. Especially glass vials without further surface modifications, like Exp33 and Exp51 vials, showed significant (I) vial-to-vial variations within one vial lot as well as (II) variations along the vertical axis of a single vial when studying topography and chemical composition. In addition, differences and heterogeneity in surface energy were found within a given tranche (circumferential direction) of Exp51 as well as Type I plus® vials. Most consistent quality was achieved with TopLyo™ vials. The present comprehensive characterization of surface properties of the different vial types may serve as basis to further guide the selection of adequate primary packaging based on the desired quality target product profile and to support studies of glass surface interactions with formulations. The proposed analytical method panel can be used for characterization of future glass vials either before delivery to the manufacturer or drug product manufacturing. Copyright © 2018 Elsevier B.V. All rights reserved.

Direction of CRT waste glass processing: electronics recycling industry communication.

PubMed

Mueller, Julia R; Boehm, Michael W; Drummond, Charles

2012-08-01

Cathode Ray Tube, CRT, waste glass recycling has plagued glass manufacturers, electronics recyclers and electronics waste policy makers for decades because the total supply of waste glass exceeds demand, and the formulations of CRT glass are ill suited for most reuse options. The solutions are to separate the undesirable components (e.g. lead oxide) in the waste and create demand for new products. Achieving this is no simple feat, however, as there are many obstacles: limited knowledge of waste glass composition; limited automation in the recycling process; transportation of recycled material; and a weak and underdeveloped market. Thus one of the main goals of this paper is to advise electronic glass recyclers on how to best manage a diverse supply of glass waste and successfully market to end users. Further, this paper offers future directions for academic and industry research. To develop the recommendations offered here, a combination of approaches were used: (1) a thorough study of historic trends in CRT glass chemistry; (2) bulk glass collection and analysis of cullet from a large-scale glass recycler; (3) conversations with industry members and a review of potential applications; and (4) evaluation of the economic viability of specific uses for recycled CRT glass. If academia and industry can solve these problems (for example by creating a database of composition organized by manufacturer and glass source) then the reuse of CRT glass can be increased. Copyright © 2012 Elsevier Ltd. All rights reserved.

Ion-Exchange Interdiffusion Model with Potential Application to Long-Term Nuclear Waste Glass Performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neeway, James Joseph; Kerisit, Sebastien N.; Liu, Jia

2016-05-05

Abstract: Ion exchange is an integral mechanism influencing the corrosion of glasses. Due to the formation of alteration layers in aqueous conditions, it is difficult to conclusively deconvolute the process of ion exchange from other processes, principally dissolution of the glass matrix. Therefore, we have developed a method to isolate alkali diffusion that involves contacting glass coupons with a solution of 6LiCl dissolved in functionally inert dimethyl sulfoxide. We employ the method at temperatures ranging from 25 to 150 °C with various glass formulations. Glass compositions include simulant nuclear waste glasses, such as SON68 and the international simple glass (ISG),more » glasses in which the nature of the alkali element was varied, and glasses that contained more than one alkali element. An interdiffusion model based on Fick’s second law was developed and applied to all experiments to extract diffusion coefficients. The model expands established models of interdiffusion to the case where multiple types of alkali sites are present in the glass. Activation energies for alkali ion exchange were calculated and the results are in agreement with those obtained in glass strengthening experiments but are nearly five times higher than values reported for diffusion-controlled processes in nuclear waste glass corrosion experiments. A discussion of the root causes for this apparent discrepancy is provided. The interdiffusion model derived from laboratory experiments is expected to be useful for modeling glass corrosion in a geological repository when the silicon concentration is high.« less

N-vinylpyrrolidone modified glass-ionomer resins for improved dental restoratives

NASA Astrophysics Data System (ADS)

Xie, Dong

The studies described in this dissertation focus on improvement of mechanical properties of current glass-ionomer cements. Thermal properties and microstructures of the cements were correlated with their mechanical strengths. The first study evaluated mechanical properties of selected commercial glass-ionomer cements and examined their microstructures. The results showed that resin-modified glass-ionomer cements (RM GICs) exhibited much higher flexural (FS) and diametral tensile strengths (DTS), compared to conventional GICs (C GICs). In addition, they exhibited comparable compressive strength (CS), relatively low microhardness and less wear resistance than C GICs. The C GICs exhibited brittle behavior, whereas the RM GICs underwent substantial plastic deformation in compression. The mechanical properties of the GICs were closely related to their microstructures. Factors such as the density of the microstructure, the integrity of the interface between the glass particles and polymer matrix, particle size and the number and size of voids have important roles in determining the mechanical properties. The second study evaluated thermal properties of these GICs. The results showed that the RM GICs exhibited higher thermal transition temperatures than those of the C GICs, thermal expansion coefficients of these cements were close to those of human teeth, and the indentation creep of the RM GICs were higher than the C GICs. The third study explored and evaluated the effect of a water-soluble monomer, N-vinylpyrrolidone (NVP), on the performance of current C GICs, indicating a significant improvement in both mechanical and working properties. The fourth study demonstrated the process of determining the optimal molar ratio of the NVP-containing copolymers, using design of experiment. The results showed that the optimal molar ratio for these copolymers was 7:1:3 for poly(acrylic acid-co-itaconic acid-co-N-vinylpyrrolidone), based on the FS test. The molar ratio of 8:2:1 (AA:IA:NVP) was considered as the best molar ratio for these copolymers, based on the DTS and CS tests. The fifth study formulated the NVP-containing RM GICs using a statistical design of experiment. The results indicated that the best graft ratio for 2-isocyanatoethyl methacrylate (IEM) in this system was 15% of the terpolymer by a molar ratio. The optimal formulation was found to be at the weight ratio of 55:15:30 (RM NVP-containing terpolymer: 2-hydroxyethyl methacrylate (HEMA): Hsb2O). Stress-strain curves showed that a relatively high amount of water in the formulation led to higher elastic modulus and proportional limit and lower malleability, whereas a relatively high amount of HEMA gave the opposite results. The sixth study evaluated the NVP modified GICs (NVPM GICs) with the best molar ratios and optimal formulations in the mechanical, thermal and working properties. The results showed that the effect of molecular weight on mechanical properties of the NVPM GICs were evident. Different glass powders exhibited different effects on properties of the NVPM GICs, due to different compositions, size and affinity. Powder/liquid ratios had significant effects on the mechanical properties of NVPM GICs, especially on FS. P/W ratios are only beneficial to the NVPM GICs mixed with the Fuji II glass powders. The NVPM GICs showed a higher WT than the models, due to water retention of the NVP ring. Thermal expansion coefficients for the NVPM GICs were close to those for the natural tooth. Mismatch between the glass powders used and the polymer matrix was a big concern in this study and should be solved in the future.

CHARACTERIZATION OF A PRECIPITATE REACTOR FEED TANK (PRFT) SAMPLE FROM THE DEFENSE WASTE PROCESSING FACILITY (DWPF)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crawford, C.; Bannochie, C.

2014-05-12

A sample of from the Defense Waste Processing Facility (DWPF) Precipitate Reactor Feed Tank (PRFT) was pulled and sent to the Savannah River National Laboratory (SRNL) in June of 2013. The PRFT in DWPF receives Actinide Removal Process (ARP)/ Monosodium Titanate (MST) material from the 512-S Facility via the 511-S Facility. This 2.2 L sample was to be used in small-scale DWPF chemical process cell testing in the Shielded Cells Facility of SRNL. A 1L sub-sample portion was characterized to determine the physical properties such as weight percent solids, density, particle size distribution and crystalline phase identification. Further chemical analysismore » of the PRFT filtrate and dissolved slurry included metals and anions as well as carbon and base analysis. This technical report describes the characterization and analysis of the PRFT sample from DWPF. At SRNL, the 2.2 L PRFT sample was composited from eleven separate samples received from DWPF. The visible solids were observed to be relatively quick settling which allowed for the rinsing of the original shipping vials with PRFT supernate on the same day as compositing. Most analyses were performed in triplicate except for particle size distribution (PSD), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and thermogravimetric analysis (TGA). PRFT slurry samples were dissolved using a mixed HNO3/HF acid for subsequent Inductively Coupled Plasma Atomic Emission Spectroscopy (ICPAES) and Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) analyses performed by SRNL Analytical Development (AD). Per the task request for this work, analysis of the PRFT slurry and filtrate for metals, anions, carbon and base were primarily performed to support the planned chemical process cell testing and to provide additional component concentrations in addition to the limited data available from DWPF. Analysis of the insoluble solids portion of the PRFT slurry was aimed at detailed characterization of these solids (TGA, PSD, XRD and SEM) in support of the Salt IPT chemistry team. The overall conclusions from analyses performed in this study are that the PRFT slurry consists of 0.61 Wt.% insoluble MST solids suspended in a 0.77 M [Na+] caustic solution containing various anions such as nitrate, nitrite, sulfate, carbonate and oxalate. The corresponding measured sulfur level in the PRFT slurry, a critical element for determining how much of the PRFT slurry gets blended into the SRAT, is 0.437 Wt.% TS. The PRFT slurry does not contain insoluble oxalates nor significant quantities of high activity sludge solids. The lack of sludge solids has been alluded to by the Salt IPT chemistry team in citing that the mixing pump has been removed from Tank 49H, the feed tank to ARP-MCU, thus allowing the sludge solids to settle out. The PRFT aqueous slurry from DWPF was found to contain 5.96 Wt.% total dried solids. Of these total dried solids, relatively low levels of insoluble solids (0.61 Wt.%) were measured. The densities of both the filtrate and slurry were 1.05 g/mL. Particle size distribution of the PRFT solids in filtered caustic simulant and XRD analysis of washed/dried PRFT solids indicate that the PRFT slurry contains a bimodal distribution of particles in the range of 1 and 6 μm and that the particles contain sodium titanium oxide hydroxide Na2Ti2O4(OH)2 crystalline material as determined by XRD. These data are in excellent agreement with similar data obtained from laboratory sampling of vendor supplied MST. Scanning Electron Microscopy (SEM) combined with Energy Dispersive X-ray Spectroscopy (EDS) analysis of washed/dried PRFT solids shows the particles to be like previous MST analyses consisting of irregular shaped micron-sized solids consisting primarily of Na and Ti. Thermogravimetric analysis of the washed and unwashed PRFT solids shows that the washed solids are very similar to MST solids. The TGA mass loss signal for the unwashed solids shows similar features to TGA performed on cellulose nitrate filter paper indicating significant presence of the deteriorated filter in this unwashed sample. Neither the washed nor unwashed PRFT solids TGA traces showed any features that would indicate presence of sodium oxalate solids. The PRFT Filtrate elemental analysis shows that Na, S and Al are major soluble species with trace levels of B, Cr, Cu, K, Li, Si, Tc, Th and U present. Nitrate, nitrite, sulfate, oxalate, carbonate and hydroxide are major soluble anion species. There is good agreement between the analyzed TOC and the total carbon calculated from the sum of oxalate and minor species formate. Comparison of the amount and speciation of the carbon species between filtrate and slurry indicates no significant carbon-containing species, e.g., sodium oxalate, are present in the slurry solids. Dissolution of the PRFT slurry and subsequent analysis shows that Na, Ti, Si and U are the major elements present on a Wt.% total dried solids basis with 30, 5.8 and 0.47 and 0.11 Wt.% total dried solids, respectively. The amount of Al in the dissolved PRFT slurry is less than that calculated from the PRFT filtrate alone which suggests that the mixed acid digestion used in this work is not optimized for Al recovery. The concentrations of Ca, Fe, Hg and U are all low (at or below 0.11 wt%) and there is no detectable Mn or Ni present which indicates no significant HLW sludge solids are present in the PRFT slurry sample.« less

Impact Damage on a Thin Glass Plate with a Thin Polycarbonate Backing

DTIC Science & Technology

2013-07-13

fixed and equals 0.25 in 3D (close to the soda-lime glass Poisson ratio of 0.22), and 1/3 in 2D, since the assumption is that material points interact...only through a pair-potential. The Poisson ratio limitation is removed in the state-based formulation of peridynamics (see Ref. [26]), however, here...we use the bond-based for simplicity. We note that, in dynamic fracture problems of the type considered in this work, the Poisson ratio value does not

Chaotic behavior of a spin-glass model on a Cayley tree

NASA Astrophysics Data System (ADS)

da Costa, F. A.; de Araújo, J. M.; Salinas, S. R.

2015-06-01

We investigate the phase diagram of a spin-1 Ising spin-glass model on a Cayley tree. According to early work of Thompson and collaborators, this problem can be formulated in terms of a set of nonlinear discrete recursion relations along the branches of the tree. Physically relevant solutions correspond to the attractors of these mapping equations. In the limit of infinite coordination of the tree, and for some choices of the model parameters, we make contact with findings for the phase diagram of more recently investigated versions of the Blume-Emery-Griffiths spin-glass model. In addition to the anticipated phases, we numerically characterize the existence of modulated and chaotic structures.

Slow Crack Growth of Brittle Materials With Exponential Crack-Velocity Formulation. Part 2; Constant Stress Rate Experiments

NASA Technical Reports Server (NTRS)

Choi, Sung R.; Nemeth, Noel N.; Gyekenyesi, John P.

2002-01-01

The previously determined life prediction analysis based on an exponential crack-velocity formulation was examined using a variety of experimental data on glass and advanced structural ceramics in constant stress rate and preload testing at ambient and elevated temperatures. The data fit to the relation of strength versus the log of the stress rate was very reasonable for most of the materials. Also, the preloading technique was determined equally applicable to the case of slow-crack-growth (SCG) parameter n greater than 30 for both the power-law and exponential formulations. The major limitation in the exponential crack-velocity formulation, however, was that the inert strength of a material must be known a priori to evaluate the important SCG parameter n, a significant drawback as compared with the conventional power-law crack-velocity formulation.

Development of dense glass-ceramic from recycled soda-lime-silicate glass and fly ash for tiling

NASA Astrophysics Data System (ADS)

Mustaffar, Mohd Idham; Mahmud, Mohamad Haniza; Hassan, Mahadi Abu

2017-12-01

Dense glass-ceramics were prepared by sinter-crystallization process from a combination of soda-lime-silicate glass waste and fly ash. Bentonite clay that acted as a binder was also added in a prepared formulation. The powder mixture of soda-lime glass, fly ash and bentonite clay were compacted by using uniaxial hydraulic press machine and sintered at six (6) various temperatures namely 750, 800, 850, 900, 950 and 1000 °C. The heating rate and sintering time were set at 5 °C/min and 30 minutes respectively. The results revealed that modulus of rupture (MOR), density and linear shrinkage increase first from 750 to 800 °C but decrease later after 800 to 1000 °C. In the meantime, water absorption was showing completely an opposite trend. The glass-ceramic sintered at 800 °C was found to have the best combination of physical-mechanical properties and has the potential to be applied in the construction industry particularly as floor and wall tiles because of the simple manufacturing process at low temperature.

Characterization of Dynamics in Complex Lyophilized Formulations: I. Comparison of Relaxation Times Measured by Isothermal Calorimetry with Data Estimated from the Width of the Glass Transition Temperature Region

PubMed Central

Chieng, Norman; Mizuno, Masayasu; Pikal, Michael

2013-01-01

The purposes of this study are to characterize the relaxation dynamics in complex freeze dried formulations and to investigate the quantitative relationship between the structural relaxation time as measured by thermal activity monitor (TAM) and that estimated from the width of the glass transition temperature (ΔTg). The latter method has advantages over TAM because it is simple and quick. As part of this objective, we evaluate the accuracy in estimating relaxation time data at higher temperatures (50°C and 60°C) from TAM data at lower temperature (40°C) and glass transition region width (ΔTg) data obtained by differential scanning calorimetry. Formulations studied here were hydroxyethyl starch (HES)-disaccharide, HES-polyol and HES-disaccharide-polyol at various ratios. We also re-examine, using TAM derived relaxation times, the correlation between protein stability (human growth hormone, hGH) and relaxation times explored in a previous report, which employed relaxation time data obtained from ΔTg. Results show that most of the freeze dried formulations exist in single amorphous phase, and structural relaxation times were successfully measured for these systems. We find a reasonably good correlation between TAM measured relaxation times and corresponding data obtained from estimates based on ΔTg, but the agreement is only qualitative. The comparison plot showed that TAM data is directly proportional to the 1/3 power of ΔTg data, after correcting for an offset. Nevertheless, the correlation between hGH stability and relaxation time remained qualitatively the same as found with using ΔTg derived relaxation data, and it was found that the modest extrapolation of TAM data to higher temperatures using ΔTg method and TAM data at 40°C resulted in quantitative agreement with TAM measurements made at 50 °C and 60 °C, provided the TAM experiment temperature is well below the Tg of the sample. PMID:23608636

Biological Impact of Bioactive Glasses and Their Dissolution Products.

PubMed

Hoppe, Alexander; Boccaccini, Aldo R

2015-01-01

For many years, bioactive glasses (BGs) have been widely considered for bone tissue engineering applications due to their ability to bond to hard as well as soft tissue (a property termed bioactivity) and for their stimulating effects on bone formation. Ionic dissolution products released during the degradation of the BG matrix induce osteogenic gene expression leading to enhanced bone regeneration. Recently, adding bioactive metallic ions (e.g. boron, copper, cobalt, silver, zinc and strontium) to silicate (or phosphate and borate) glasses has emerged as a promising route for developing novel BG formulations with specific therapeutic functionalities, including antibacterial, angiogenic and osteogenic properties. The degradation behaviour of BGs can be tailored by adjusting the glass chemistry making these glass matrices potential carrier systems for controlled therapeutic ion release. This book chapter summarises the fundamental aspects of the effect of ionic dissolution products from BGs on osteogenesis and angiogenesis, whilst discussing novel BG compositions with controlled therapeutic ion release. © 2015 S. Karger AG, Basel.

The role of troublesome components in plutonium vitrification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Hong; Vienna, J.D.; Peeler, D.K.

1996-05-01

One option for immobilizing surplus plutonium is vitrification in a borosilicate glass. Two advantages of the glass form are (1) high tolerance to feed variability and, (2) high solubility of some impurity components. The types of plutonium-containing materials in the United States inventory include: pits, metals, oxides, residues, scrap, compounds, and fuel. Many of them also contain high concentrations of carbon, chloride, fluoride, phosphate, sulfate, and chromium oxide. To vitrify plutonium-containing scrap and residues, it is critical to understand the impact of each component on glass processing and chemical durability of the final product. This paper addresses glass processing issuesmore » associated with these troublesome components. It covers solubility limits of chlorine, fluorine, phosphate, sulfate, and chromium oxide in several borosilicate based glasses, and the effect of each component on vitrification (volatility, phase segregation, crystallization, and melt viscosity). Techniques (formulation, pretreatment, removal, and/or dilution) to mitigate the effect of these troublesome components are suggested.« less

DEVELOPMENT OF AN ANTIFOAM TRACKING SYSTEM AS AN OPTION TO SUPPORT THE MELTER OFF-GAS FLAMMABILITY CONTROL STRATEGY AT THE DWPF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, T.; Lambert, D.

The Savannah River National Laboratory (SRNL) has been working with the Savannah River Remediation (SRR) Defense Waste Processing Facility (DWPF) in the development and implementation of an additional strategy for confidently satisfying the flammability controls for DWPF’s melter operation. An initial strategy for implementing the operational constraints associated with flammability control in DWPF was based upon an analytically determined carbon concentration from antifoam. Due to the conservative error structure associated with the analytical approach, its implementation has significantly reduced the operating window for processing and has led to recurrent Slurry Mix Evaporator (SME) and Melter Feed Tank (MFT) remediation. Tomore » address the adverse operating impact of the current implementation strategy, SRR issued a Technical Task Request (TTR) to SRNL requesting the development and documentation of an alternate strategy for evaluating the carbon contribution from antifoam. The proposed strategy presented in this report was developed under the guidance of a Task Technical and Quality Assurance Plan (TTQAP) and involves calculating the carbon concentration from antifoam based upon the actual mass of antifoam added to the process assuming 100% retention. The mass of antifoam in the Additive Mix Feed Tank (AMFT), in the Sludge Receipt and Adjustment Tank (SRAT), and in the SME is tracked by mass balance as part of this strategy. As these quantities are monitored, the random and bias uncertainties affecting their values are also maintained and accounted for. This report documents: 1) the development of an alternate implementation strategy and associated equations describing the carbon concentration from antifoam in each SME batch derived from the actual amount of antifoam introduced into the AMFT, SRAT, and SME during the processing of the batch. 2) the equations and error structure for incorporating the proposed strategy into melter off-gas flammability assessments. Sample calculations of the system are also included in this report. Please note that the system developed and documented in this report is intended as an alternative to the current, analytically-driven system being utilized by DWPF; the proposed system is not intended to eliminate the current system. Also note that the system developed in this report to track antifoam mass in the AMFT, SRAT, and SME will be applicable beyond just Sludge Batch 8. While the model used to determine acceptability of the SME product with respect to melter off-gas flammability controls must be reassessed for each change in sludge batch, the antifoam mass tracking methodology is independent of sludge batch composition and as such will be transferable to future sludge batches.« less

Qualitative and quantitative measures of various compounded formulations of 17-hydroxyprogesterone caproate

PubMed Central

CARITIS, Steve N.; ZHAO, Yang; BETTINGER, Joseph; VENKATARAMANAN, Raman

2013-01-01

Objectives 17-hydroxyprogesterone caproate (17-OHPC) is available both as an FDA – approved medication and as a product prepared for individual patients by compounding pharmacies. Compounding pharmacies may omit the preservative used in the FDA approved formulation or use an alternate preservative and may dispense 17-OHPC in containers that differ from the FDA-approved product. The objective of this study was to assess the stability, microbiological and pyrogen status of 17-OHPC formulations under various compounding and dispensing conditions. Methods 17-OHPC was prepared by a local compounding pharmacy. The formulations prepared included one identical to the FDA approved product with benzyl alcohol as a preservative, one with benzalkonium chloride as a preservative and one without a preservative. These various formulations were dispensed into either single dose 1 ml plastic syringes or glass vials or 10 ml glass vials. Concentration of 17-OHPC and microbial and pyrogen status were evaluated at various time intervals over the ensuing 19 weeks. Results The concentration of 17-OHPC did not change over the duration of study regardless of the dispensing medium used or the absence or presence of any preservatives. The preparations remained microbe and pyrogen free during the study period regardless of the dispensing medium used or the absence of presence of any preservatives. Conclusions Products containing 17-OPHC tested in this study were quite stable over the 19-week period of study in different dispensing containers and in absence or presence of a different preservative. The compounded products remained sterile and pyrogen free during the period of observation. PMID:23453884

Preliminary study of the effects of a reversible chemical reaction on gas bubble dissolution. [for space glass refining

NASA Technical Reports Server (NTRS)

Weinberg, M. C.

1982-01-01

A preliminary investigation is carried out of the effects of a reversible chemical reaction on the dissolution of an isolated, stationary gas bubble in a glass melt. The exact governing equations for the model system are formulated and analyzed. The approximate quasi-steady-state version of these equations is solved analytically, and a calculation is made of bubble dissolution rates. The results are then compared with numerical solutions obtained from the finite difference form of the exact governing equations. It is pointed out that in the microgravity condition of space, the buoyant rise of a gas bubble in a glass melt will be negligible on the time scale of most experiments. For this reason, a determination of the behavior of a stationary gas bubble in a melt is relevant for an understanding of glass refining in space.

Effect of powder to liquid ratio on tensile strength and glass transition temperature of alumina filled poly methyl methacrylate (PMMA) denture base material.

PubMed

Mohamed, S H; Arifin, A; Mohd Ishak, Z A; Nizam, A; Samsudin, A R

2004-05-01

The aim of this study was to evaluate the mechanical properties and glass transition temperature (Tg) of a denture base material prepared from high molecular weight poly methyl methacrylate (PMMA) and alumina (Al2O3). The glass transition temperature was studied by using differential scanning calorimetry (DSC). The effect of powder-to-liquid ratio was investigated. The result showed that the tensile properties and the Tg were slightly effected by the powder-to-liquid ratio. The ratio of 2.2:1 by weight of powder to liquid was found to be the best ratio for mixing the material to give the best result in this formulation.

Examining porous bio-active glass as a potential osteo-odonto-keratoprosthetic skirt material.

PubMed

Huhtinen, Reeta; Sandeman, Susan; Rose, Susanna; Fok, Elsie; Howell, Carol; Fröberg, Linda; Moritz, Niko; Hupa, Leena; Lloyd, Andrew

2013-05-01

Bio-active glass has been developed for use as a bone substitute with strong osteo-inductive capacity and the ability to form strong bonds with soft and hard tissue. The ability of this material to enhance tissue in-growth suggests its potential use as a substitute for the dental laminate of an osteo-odonto-keratoprosthesis. A preliminary in vitro investigation of porous bio-active glass as an OOKP skirt material was carried out. Porous glass structures were manufactured from bio-active glasses 1-98 and 28-04 containing varying oxide formulation (1-98, 28-04) and particle size range (250-315 μm for 1-98 and 28-04a, 315-500 μm for 28-04b). Dissolution of the porous glass structure and its effect on pH was measured. Structural 2D and 3D analysis of porous structures were performed. Cell culture experiments were carried out to study keratocyte adhesion and the inflammatory response induced by the porous glass materials. The dissolution results suggested that the porous structure made out of 1-98 dissolves faster than the structures made from glass 28-04. pH experiments showed that the dissolution of the porous glass increased the pH of the surrounding solution. The cell culture results showed that keratocytes adhered onto the surface of each of the porous glass structures, but cell adhesion and spreading was greatest for the 98a bio-glass. Cytokine production by all porous glass samples was similar to that of the negative control indicating that the glasses do not induce a cytokine driven inflammatory response. Cell culture results support the potential use of synthetic porous bio-glass as an OOKP skirt material in terms of limited inflammatory potential and capacity to induce and support tissue ingrowth.

Prediction of glass durability as a function of environmental conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C M

1988-01-01

A thermodynamic model of glass durability is applied to natural, ancient, and nuclear waste glasses. The durabilities of over 150 different natural and man-made glasses, including actual ancient Roman and Islamic glasses (Jalame ca. 350 AD, Nishapur 10-11th century AD and Gorgon 9-11th century AD), are compared. Glass durability is a function of the thermodynamic hydration free energy, ..delta..G/sub hyd/, which can be calculated from glass composition and solution pH. The durability of the most durable nuclear waste glasses examined was /approximately/10/sup 6/ years. The least durable waste glass formulations were comparable in durability to the most durable simulated medievalmore » window glasses of /approximately/10/sup 3/ years. In this manner, the durability of nuclear waste glasses has been interpolated to be /approximately/10/sup 6/ years and no less than 10/sup 3/ years. Hydration thermodynamics have been shown to be applicable to the dissolution of glass in various natural environments. Groundwater-glass interactions relative to geologic disposal of nuclear waste, hydration rind dating of obsidians, andor other archeological studies can be modeled, e.g., the relative durabilities of six simulated medieval window glasses have been correctly predicted for both laboratory (one month) and burial (5 years) experiments. Effects of solution pH on glass dissolution has been determined experimentally for the 150 different glasses and can be predicted theoretically by hydration thermodynamics. The effects of solution redox on dissolution of glass matrix elements such as SI and B have shown to be minimal. The combined effects of solution pH and Eh have been described and unified by construction of thermodynamically calculated Pourbaix (pH-Eh) diagrams for glass dissolution. The Pourbaix diagrams have been quantified to describe glass dissolution as a function of environmental conditions by use of the data derived from hydration thermodynamics. 56 refs., 7 figs.« less

[Study of Interaction between Fluorinated Coating Glass and the Medicines].

PubMed

Kawano, Yayoi; Otsu, Saki; Bamba, Takao; Hanawa, Takehisa

2017-11-01

 The adsorption of active pharmaceutical ingredients on the surface of medical devices such as polyvinl chloride, ethylene-vinyl acetate copolymer and glass often prevent the acuurate dose of drug. At dispensing of pharmaceuticals, mètre glass (MG) has been widely used for dispensing syrup. When measuring the viscous syrup, it often takes long time to dispense the accurate volume due to their adhesiveness on the glass surface. In this study, we investigate the adhesion of various syrups to MG made with uncoated glass or glass with a strongly hydrophobic silicone or fluorinated coating in terms of the following formulation parameters: viscosity, surface tension, contact angle, and surface free energy. The contact angles for syrups on the coated glass surfaces were significantly higher than those on the uncoated glass surface. In addition, the relationship between surface tension and contact angle was examined. We found that the contact angle was independent of surface tension for the uncoated glass, while it increased with increasing surface tension for the coated glasses. These results can be explained as follows: the silicone or fluorinated coatings inhibit the hydrogen bonding that usually takes place between water and silanol and siloxane groups at glass surfaces. The coatings reduced the surface free energy and increased the hydrophobicity of the glass, reduced its wettability by the syrups, and thus reduced the adhesion loss for the syrups. It was considered that as for the hydrophobic action, properties of matter of sample influence the coated device by coating in order that it is reinforced.

Burn/Blast Tests of Miscellaneous Graphite Composite Parts.

DTIC Science & Technology

1979-11-01

accommodate the size of the test fixture sample holder. The QCSEE fan blade consisted of various layers of KEVLAR (polyaramid fiber), S-glass, AS graphite...panel tested was a 14-ply laminate of W-134 graphite and MXG 6070 modified phenolic resin. This was an experimental formulation pro- posed as an...166/X-130 T-Section T-300/5209 epoxy 17 x 26 20 1122 skin-to-spar ST-163/X-127 QCSEE Kevlar /AS/Glass/B/PR 24 x 29 20 1204 fan blade BT-164/X-128 Le1C

Anti-reflective and anti-soiling coatings for self-cleaning properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brophy, Brenor L.; Nair, Vinod; Dave, Bakul Champaklal

The disclosure discloses abrasion resistant, persistently hydrophobic and oleophobic, anti-reflective and anti-soiling coatings for glass. The coatings described herein have wide application, including for example the front cover glass of solar modules. Methods of applying the coatings using various apparatus are disclosed. Methods for using the coatings in solar energy generation plants to achieve greater energy yield and reduced operations costs are disclosed. Coating materials are formed by combinations of hydrolyzed silane-base precursors through sol-gel processes. Several methods of synthesis and formulation of coating materials are disclosed.

Formulation design for optimal high-shear wet granulation using on-line torque measurements.

PubMed

Cavinato, Mauro; Bresciani, Massimo; Machin, Marianna; Bellazzi, Guido; Canu, Paolo; Santomaso, Andrea C

2010-03-15

An alternative procedure for achieving formulation design in a high-shear wet granulation process has been developed. Particularly, a new formulation map has been proposed which describes the onset of a significant granule growth as a function of the formulation variables (diluent, dry and liquid binder). Granule growth has been monitored using on-line impeller torque and evaluated as changes in granule particle size distribution with respect to the dry formulation. It is shown how the onset of granule growth is denoted by an abrupt increase in the torque value requires the amount of binder liquid added to be greater than a certain threshold that is identified here as 'minimum liquid volume'. This minimum liquid volume is determined as a function of dry binder type, amount, hygroscopicity and particle size distribution of diluent. It is also demonstrated how this formulation map can be constructed from independent measurements of binder glass transition temperatures using a static humidity conditioning system. 2009 Elsevier B.V. All rights reserved.

Improved photostability of NREL-developed EVA pottant formulations for PV module encapsulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pern, F.J.; Glick, S.H.

1997-12-31

Several new formulations of ethylene vinyl acetate (EVA)-based encapsulant have been developed at NREL and have greatly improved photostability against UV-induced discoloration. The new EVA formulations use stabilizers and a curing agent entirely different from any of those used in existing formulations known to the authors. No discoloration was observed for the laminated and cured samples that were exposed to a {approximately}5-sun UV light (300--400 nm) from a solar simulator at a black panel temperature (BPT) of 44 {+-} 2 C for {approximately}3250 h followed by at 85 C for {approximately}850 h, an equivalent of approximately 9.4 years for anmore » average 6-h daily, 1-sun solar exposure in Golden, Colorado. Under the same conditions, substantial discoloration and premature delamination were observed for two commercial EVA formulations. Encapsulation with the new EVA formulations should extend the long-term stability for PV modules in the field, especially when coupled with UV-filtering, Ce-containing glass superstrates.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vienna, John D.; Schweiger, Michael J.; Bonham, Charles C.

Roughly half of the projected Hanford high-level waste batches will have waste loadings limited by relatively high concentration of Al2O3. Individual glasses have been formulated and tested to demonstrate that it is possible to increase the loading of these high-Al2O3 wastes in glass by as much as 50%. To implement such increases in waste loading in the Hanford Tank Waste Treatment and Immobilization Plant, the impact of composition on the properties of high-Al2O3 waste glasses must be quantified in the form of validated glass property-composition models. To collect the data necessary for glass property-composition models, a multi-phase experimental approach wasmore » developed. In the first phase of the study, a set of 46 glass compositions were statistically designed to most efficiently backfill existing data in the composition region for high-Al2O3 (15 to 30 wt%) waste glasses. The glasses were fabricated and key glass properties were tested: •Product Consistency Test (PCT) on quench (Q) and canister centerline cooled (CCC) samples •Toxicity Characteristic Leaching Procedure (TCLP) on Q and CCC samples •Crystallinity as a function of temperature (T) at equilibrium and of CCC samples •Viscosity and electrical conductivity as a function of T The measured properties of these glasses were compared to predictions from previously existing models developed over lower Al2O3 concentration ranges. Areas requiring additional testing and modeling were highlighted.« less

Tuning the morphology of silver nanostructures photochemically coated on glass substrates: an effective approach to large-scale functional surfaces

NASA Astrophysics Data System (ADS)

Zaier, Mohamed; Vidal, Loic; Hajjar-Garreau, Samar; Bubendorff, Jean-Luc; Balan, Lavinia

2017-03-01

This paper reports on a simple and environmentally friendly photochemical process capable of generating nano-layers (8-22 nm) of silver nanostructures directly onto glass surfaces. This approach opens the way to large-scale functionalized surfaces with plasmonic properties through a single light-induced processing. Thus, Ag nanostructures top-coated were obtained through photo-reduction, at room temperature, of a photosensitive formulation containing a metal precursor, free from extra toxic stabilizers or reducing agents. The reactive formulation was confined between two glass slides and exposed to a continuous near-UV source. In this way, stable silver nano-layers can be generated directly on the substrate with a very good control of the morphology of as-synthesized nanostructures that allows tailoring the optical properties of the coated layers. The position and width of the corresponding surface plasmon resonance bands can be adjusted over a broad spectral window. By extension, this low-cost and easy-to-apply process can also be used to coat ultra thin layers of metal nanostructures on a variety of substrates. The possibility of controlling of nanostructures shape should achieve valuable developments in many fields, as diverse as plasmonics, surface enhanced Raman scattering, nano-electronic circuitry, or medical devices.

Direction of CRT waste glass processing: Electronics recycling industry communication

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mueller, Julia R., E-mail: mueller.143@osu.edu; Boehm, Michael W.; Drummond, Charles

2012-08-15

Highlights: Black-Right-Pointing-Pointer Given a large flow rate of CRT glass {approx}10% of the panel glass stream will be leaded. Black-Right-Pointing-Pointer The supply of CRT waste glass exceeded demand in 2009. Black-Right-Pointing-Pointer Recyclers should use UV-light to detect lead oxide during the separation process. Black-Right-Pointing-Pointer Recycling market analysis techniques and results are given for CRT glass. Black-Right-Pointing-Pointer Academic initiatives and the necessary expansion of novel product markets are discussed. - Abstract: Cathode Ray Tube, CRT, waste glass recycling has plagued glass manufacturers, electronics recyclers and electronics waste policy makers for decades because the total supply of waste glass exceeds demand, andmore » the formulations of CRT glass are ill suited for most reuse options. The solutions are to separate the undesirable components (e.g. lead oxide) in the waste and create demand for new products. Achieving this is no simple feat, however, as there are many obstacles: limited knowledge of waste glass composition; limited automation in the recycling process; transportation of recycled material; and a weak and underdeveloped market. Thus one of the main goals of this paper is to advise electronic glass recyclers on how to best manage a diverse supply of glass waste and successfully market to end users. Further, this paper offers future directions for academic and industry research. To develop the recommendations offered here, a combination of approaches were used: (1) a thorough study of historic trends in CRT glass chemistry; (2) bulk glass collection and analysis of cullet from a large-scale glass recycler; (3) conversations with industry members and a review of potential applications; and (4) evaluation of the economic viability of specific uses for recycled CRT glass. If academia and industry can solve these problems (for example by creating a database of composition organized by manufacturer and glass source) then the reuse of CRT glass can be increased.« less

Final Report - Melt Rate Enhancement for High Aluminum HLW Glass Formulation, VSL-08R1360-1, Rev. 0, dated 12/19/08

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, Albert A.; Pegg, I. L.; Chaudhuri, M.

2013-11-13

The principal objective of the work reported here was to develop and identify HLW glass compositions that maximize waste processing rates for the aluminum limted waste composition specified by ORP while maintaining high waste loadings and acceptable glass properties. This was accomplished through a combination of crucible-scale tests, confirmation tests on the DM100 melter system, and demonstration at pilot scale (DM1200). The DM100-BL unit was selected for these tests since it was used previously with the HLW waste streams evaluated in this study, was used for tests on HLW glass compositions to support subsequent tests on the HLW Pilot Melter,more » conduct tests to determine the effect of various glass properties (viscosity and conductivity) and oxide concentrations on glass production rates with HLW feed streams, and to assess the volatility of cesium and technetium during the vitrification of an HLW AZ-102 composition. The same melter was selected for the present tests in order to maintain comparisons between the previously collected data. These tests provide information on melter processing characteristics and off-gas data, including formation of secondary phases and partitioning. Once DM100 tests were completed, one of the compositions was selected for further testing on the DM1200; the DM1200 system has been used for processing a variety of simulated Hanford waste streams. Tests on the larger melter provide processing data at one third of the scale of the actual WTP HLW melter and, therefore, provide a more accurate and reliable assessment of production rates and potential processing issues. The work focused on maximizing waste processing rates for high aluminum HLW compositions. In view of the diversity of forms of aluminum in the Hanford tanks, tests were also conducted on the DM100 to determine the effect of changes in the form of aluminum on feed properties and production rate. In addition, the work evaluated the effect on production rate of modest increases in melter operating temperature. Glass composition development was based on one of the HLW waste compositions specified by ORP that has a high concentration of aluminum. Small-scale tests were used to provide an initial screening of various glass formulations with respect to melt rates; more definitive screening was provided by the subsequent DM100 tests. Glass properties evaluated included: viscosity, electrical conductivity, crystallinity, gross glass phase separation and the 7- day Product Consistency Test (ASTM-1285). Glass property limits were based upon the reference properties for the WTP HLW melter. However, the WTP crystallinity limit (< 1 vol% at 950oC) was relaxed slightly as a waste loading constraint for the crucible melts.« less

Prediction of glass transition temperature of freeze-dried formulations by molecular dynamics simulation.

PubMed

Yoshioka, Sumie; Aso, Yukio; Kojima, Shigeo

2003-06-01

To examine whether the glass transition temperature (Tg) of freeze-dried formulations containing polymer excipients can be accurately predicted by molecular dynamics simulation using software currently available on the market. Molecular dynamics simulations were carried out for isomaltodecaose, a fragment of dextran, and alpha-glucose, the repeated unit of dextran. in the presence or absence of water molecules. Estimated values of Tg were compared with experimental values obtained by differential scanning calorimetry (DSC). Isothermal-isobaric molecular dynamics simulations (NPTMD) and isothermal molecular dynamics simulations at a constant volume (NVTMD) were carried out using the software package DISCOVER (Material Studio) with the Polymer Consortium Force Field. Mean-squared displacement and radial distribution function were calculated. NVTMD using the values of density obtained by NPTMD provided the diffusivity of glucose-ring oxygen and water oxygen in amorphous alpha-glucose and isomaltodecaose, which exhibited a discontinuity in temperature dependence due to glass transition. Tg was estimated to be approximately 400K and 500K for pure amorphous a-glucose and isomaltodecaose, respectively, and in the presence of one water molecule per glucose unit, Tg was 340K and 360K, respectively. Estimated Tg values were higher than experimentally determined values because of the very fast cooling rates in the simulations. However, decreases in Tg on hydration and increases in Tg associated with larger fragment size could be demonstrated. The results indicate that molecular dynamics simulation is a useful method for investigating the effects of hydration and molecular weight on the Tg of lyophilized formulations containing polymer excipients. although the relationship between cooling rates and Tg must first be elucidated to predict Tg vales observed by DSC measurement. January 16.

Developing a molecular picture for polymer glasses under large deformation

NASA Astrophysics Data System (ADS)

Wang, Shi-Qing; Cheng, Shiwang; Wang, Panpan

2014-03-01

Polymer glasses differ from most other types of glassy materials because they can be ductile under tensile extension. Remarkably, a ductile polymer can turn brittle and vice versa. For example, upon cooling, the glass changes from ductile to brittle at a temperature known as the brittle-ductile transition temperature (BDT). Aging causes the ductile glass to be brittle. Mechanical ``rejuvenation'' or pressurization brings a brittle glass into a ductile state. Finally, one glass can be ductile 100 degrees below Tg while another polymer is already brittle even just 10 degree below Tg. Polystyrene and bisphenol A polycarbonate are at the two extremes in the family of polymer glasses. How to rationale such a wide range of behavior in terms of a molecular picture has been a challenging task. What is the role of ``chain entanglement''? Since many of the procedures including the temperature change do not alter the ``chain entanglement'', it is clearly insufficient to explain the nature of the BDT in terms of the entanglement density. Our work attempts to answer the question of what then is the role of chain networking. We have formulated a molecular picture that presents a unifying and coherent explanation for all the known phenomenology concerning the BDT and condition for crazing. This work is supported, in part, by NSF (CMMI-0926522 and DMR-1105135).

Bubblers Speed Nuclear Waste Processing at SRS

ScienceCinema

None

2018-05-23

At the Department of Energy's Savannah River Site, American Recovery and Reinvestment Act funding has supported installation of bubbler technology and related enhancements in the Defense Waste Processing Facility (DWPF). The improvements will accelerate the processing of radioactive waste into a safe, stable form for storage and permit expedited closure of underground waste tanks holding 37 million gallons of liquid nuclear waste.

Analysis Of Condensate Samples In Support Of The Antifoam Degradation Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hay, M.; Martino, C.

2016-01-12

The degradation of Antifoam 747 to form flammable decomposition products has resulted in declaration of a Potential Inadequacy in the Safety Analysis (PISA) for the Defense Waste Processing Facility (DWPF). Savannah River National Laboratory (SRNL) testing with simulants showed that hexamethyldisiloxane (HMDSO), trimethylsilanol (TMS), and 1-propanal are formed in the offgas from the decomposition of the antifoam. A total of ten DWPF condensate samples from Batch 735 and 736 were analyzed by SRNL for three degradation products and additional analytes. All of the samples were analyzed to determine the concentrations of HMDSO, TMS, and propanal. The results of the organicmore » analysis found concentrations for propanal and HMDSO near or below the detection limits for the analysis. The TMS concentrations ranged from below detection to 11 mg/L. The samples from Batch 736 were also analyzed for formate and oxalate anions, total organic carbon, and aluminum, iron, manganese, and silicon. Most of the samples contained low levels of formate and therefore low levels of organic carbon. These two values for each sample show reasonable agreement in most cases. Low levels of all the metals (Al, Fe, Mn, and Si) were present in most of the samples.« less

ANALYSIS OF CONDENSATE SAMPLES IN SUPPORT OF THE ANTIFOAM DEGRADATION STUDY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hay, M.; Martino, C.

2016-02-29

The degradation of Antifoam 747 to form flammable decomposition products has resulted in declaration of a Potential Inadequacy in the Safety Analysis (PISA) for the Defense Waste Processing Facility (DWPF). Savannah River National Laboratory (SRNL) testing with simulants showed that hexamethyldisiloxane (HMDSO), trimethylsilanol (TMS), and 1-propanal are formed in the offgas from the decomposition of the antifoam. A total of ten DWPF condensate samples from Batch 735 and 736 were analyzed by SRNL for three degradation products and additional analytes. All of the samples were analyzed to determine the concentrations of HMDSO, TMS, and propanal. The results of the organicmore » analysis found concentrations for propanal and HMDSO near or below the detection limits for the analysis. The TMS concentrations ranged from below detection to 11 mg/L. The samples from Batch 736 were also analyzed for formate and oxalate anions, total organic carbon, and aluminum, iron, manganese, and silicon. Most of the samples contained low levels of formate and therefore low levels of organic carbon. These two values for each sample show reasonable agreement in most cases. Low levels of all the metals (Al, Fe, Mn, and Si) were present in most of the samples.« less

Iron specificity of a biosensor based on fluorescent pyoverdin immobilized in sol-gel glass

PubMed Central

2011-01-01

Two current technologies used in biosensor development are very promising: 1. The sol-gel process of making microporous glass at room temperature, and 2. Using a fluorescent compound that undergoes fluorescence quenching in response to a specific analyte. These technologies have been combined to produce an iron biosensor. To optimize the iron (II or III) specificity of an iron biosensor, pyoverdin (a fluorescent siderophore produced by Pseudomonas spp.) was immobilized in 3 formulations of porous sol-gel glass. The formulations, A, B, and C, varied in the amount of water added, resulting in respective R values (molar ratio of water:silicon) of 5.6, 8.2, and 10.8. Pyoverdin-doped sol-gel pellets were placed in a flow cell in a fluorometer and the fluorescence quenching was measured as pellets were exposed to 0.28 - 0.56 mM iron (II or III). After 10 minutes of exposure to iron, ferrous ion caused a small fluorescence quenching (89 - 97% of the initial fluorescence, over the range of iron tested) while ferric ion caused much greater quenching (65 - 88%). The most specific and linear response was observed for pyoverdin immobilized in sol-gel C. In contrast, a solution of pyoverdin (3.0 μM) exposed to iron (II or III) for 10 minutes showed an increase in fluorescence (101 - 114%) at low ferrous concentrations (0.45 - 2.18 μM) while exposure to all ferric ion concentrations (0.45 - 3.03 μM) caused quenching. In summary, the iron specificity of pyoverdin was improved by immobilizing it in sol-gel glass C. PMID:21554740

An observational study of the effect of vibration on the caking of suspensions in oily vehicles.

PubMed

Jain, Rohit; Bork, Olaf; Alawi, Fadil; Nanjan, Karthigeyan; Tucker, Ian G

2016-11-30

An oily suspension of penethamate (PNT) that was physically stable on storage, caked solidly during road/air transport. This paper reports on the caking behaviour of PNT oily suspension formulations exposed to vibrations in a lab-based test designed to simulate road/air transport. The lab-test was used to study the effects of container type (glass v PET) and formulation (oil, surfactant type and concentration) on the physical stability of suspension under vibration. Redispersibility of the sediment was lower at longer vibrations times and at higher intensity of vibration. Caking on vibration was strongly influenced by the type of container (caking in glass but not in PET) possibly due to tribo-charging of particles. Caking on vibration was dependent on the formulation: type and concentration of surfactant; type of oil. The physical stability of oily suspensions, and the effect of vibration are two areas which have been largely neglected in the pharmaceutical literature. This paper discusses some potential mechanisms for the observations but studies using fully characterised materials are required. Finally we conclude that static testing of physical stability of oily suspensions is not sufficient and that a vibrational stress test is required. Copyright © 2016 Elsevier B.V. All rights reserved.

Localized chemistry of 99Tc in simulated low activity waste glass

NASA Astrophysics Data System (ADS)

Weaver, Jamie L.

A priority of the United States Department of Energy (DOE) is to dispose of the nuclear waste accumulated in the underground tanks at the Hanford Nuclear Reservation in Richland, WA. Incorporation and stabilization of technetium (99Tc) from these tanks into vitrified waste forms is a concern to the waste glass community and DOE due to 99Tc's long half-life ( 2.13˙105 y), and its high mobility in the subsurface environment under oxidizing conditions. Working in collaboration with researchers at Pacific Northwest National Laboratory (PNNL) and other national laboratories, plans were formulated to obtain first-of-a-kind chemical structure determination of poorly understood and environmentally relevant technetium compounds that relate to the chemistry of the Tc in nuclear waste glasses. Knowledge of the structure and spectral signature of these compounds aid in refining the understanding of 99Tc incorporation into and release from oxide based waste glass. In this research a first-of-its kind mechanism for the behavior of 99Tc during vitrification is presented, and the structural role of Tc(VII) and (IV) in borosilicate waste glasses is readdressed.

A Theoretical Model for Estimation of Yield Strength of Fiber Metal Laminate

NASA Astrophysics Data System (ADS)

Bhat, Sunil; Nagesh, Suresh; Umesh, C. K.; Narayanan, S.

2017-08-01

The paper presents a theoretical model for estimation of yield strength of fiber metal laminate. Principles of elasticity and formulation of residual stress are employed to determine the stress state in metal layer of the laminate that is found to be higher than the stress applied over the laminate resulting in reduced yield strength of the laminate in comparison with that of the metal layer. The model is tested over 4A-3/2 Glare laminate comprising three thin aerospace 2014-T6 aluminum alloy layers alternately bonded adhesively with two prepregs, each prepreg built up of three uni-directional glass fiber layers laid in longitudinal and transverse directions. Laminates with prepregs of E-Glass and S-Glass fibers are investigated separately under uni-axial tension. Yield strengths of both the Glare variants are found to be less than that of aluminum alloy with use of S-Glass fiber resulting in higher laminate yield strength than with the use of E-Glass fiber. Results from finite element analysis and tensile tests conducted over the laminates substantiate the theoretical model.

Final Report - Management of High Sulfur HLW, VSL-13R2920-1, Rev. 0, dated 10/31/2013

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, Albert A.; Gan, H.; Pegg, I. L.

2013-11-13

The present report describes results from a series of small-scale crucible tests to determine the extent of corrosion associated with sulfur containing HLW glasses and to develop a glass composition for a sulfur-rich HLW waste stream, which was then subjected to small-scale melter testing to determine the maximum acceptable sulfate loadings. In the present work, a new glass formulation was developed and tested for a projected Hanford HLW composition with sulfate concentrations high enough to limit waste loading. Testing was then performed on the DM10 melter system at successively higher waste loadings to determine the maximum waste loading without themore » formation of a separate sulfate salt phase. Small scale corrosion testing was also conducted using the glass developed in the present work, the glass developed in the initial phase of this work [26], and a high iron composition, all at maximum sulfur concentrations determined from melter testing, in order to assess the extent of Inconel 690 and MA758 corrosion at elevated sulfate contents.« less

The concept of the phases ratio control during the formation of composite filamentary nanocrystals xInSe-(1-x)In2O3 on glass substrates

NASA Astrophysics Data System (ADS)

Gasanly, S. A.; Tomaev, V. V.; Stoyanova, T. V.

2017-11-01

The method of vacuum deposition on substrates of glass marks the C-29 series PbSe deposited film and the film In the area 3x3 mm2 and a thickness of ˜1 μm. Films are oxidized in dry air at a temperature of 550 °C. Based on studies by X-ray microanalysis and scanning electron microscopy shows the principal possibility of formation of nanowires xInSe-(1-x)In2O3 on the PbSe/In structure. The results allowed to formulate the concept of the control of phases ratio in the forming nanowires xInSe-(1-x)In2O3 on glass substrates.

Characterization of dynamics in complex lyophilized formulations: I. Comparison of relaxation times measured by isothermal calorimetry with data estimated from the width of the glass transition temperature region.

PubMed

Chieng, Norman; Mizuno, Masayasu; Pikal, Michael

2013-10-01

The purposes of this study are to characterize the relaxation dynamics in complex freeze dried formulations and to investigate the quantitative relationship between the structural relaxation time as measured by thermal activity monitor (TAM) and that estimated from the width of the glass transition temperature (ΔT(g)). The latter method has advantages over TAM because it is simple and quick. As part of this objective, we evaluate the accuracy in estimating relaxation time data at higher temperatures (50 °C and 60 °C) from TAM data at lower temperature (40 °C) and glass transition region width (ΔT(g)) data obtained by differential scanning calorimetry. Formulations studied here were hydroxyethyl starch (HES)-disaccharide, HES-polyol, and HES-disaccharide-polyol at various ratios. We also re-examine, using TAM derived relaxation times, the correlation between protein stability (human growth hormone, hGH) and relaxation times explored in a previous report, which employed relaxation time data obtained from ΔT(g). Results show that most of the freeze dried formulations exist in single amorphous phase, and structural relaxation times were successfully measured for these systems. We find a reasonably good correlation between TAM measured relaxation times and corresponding data obtained from estimates based on ΔT(g), but the agreement is only qualitative. The comparison plot showed that TAM data are directly proportional to the 1/3 power of ΔT(g) data, after correcting for an offset. Nevertheless, the correlation between hGH stability and relaxation time remained qualitatively the same as found with using ΔT(g) derived relaxation data, and it was found that the modest extrapolation of TAM data to higher temperatures using ΔT(g) method and TAM data at 40 °C resulted in quantitative agreement with TAM measurements made at 50 °C and 60 °C, provided the TAM experiment temperature, is well below the Tg of the sample. Copyright © 2013 Elsevier B.V. All rights reserved.

One year comparative clinical evaluation of EQUIA with resin-modified glass ionomer and a nanohybrid composite in noncarious cervical lesions

PubMed Central

Vaid, Deepa Sunil; Shah, Nimisha Chinmay; Bilgi, Priyanka Shripad

2015-01-01

Aims: Comparative evaluation of EQUIA with a resin-modified glass ionomer cement (RMGIC; GC Gold Label glass ionomer light cured universal restorative cement) and a nanohybrid composite (Tetric N-Ceram) in noncarious cervical lesions (NCCLs). Background: To establish the most suitable material for the restoration of NCCLs. Settings and Design: In vivo study. Materials and Methods: Eighty-seven NCCLs were randomly restored with EQUIA, a RMGIC, and a nanohybrid composite. Clinical evaluation of the restorations was done following the Unites States Public Health criteria by a single-blinded investigator. Data were formulated, and statistical analysis was done by Chi-square test. Statistical Analysis Used: Chi-square test. Results: No significant difference was found between EQUIA, RMGIC, and nanohybrid composite at 1-month, at 6 months, and at 1-year (P > 0.05). Conclusions: EQUIA, resin-modified glass ionomer, and nanohybrid composite performed equally at 1-month, 6 months, and 1-year follow-up periods. PMID:26752837

Office of River Protection Advanced Low-Activity Waste Glass Research and Development Plan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, A. A.; Peeler, D. K.; Kim, D. S.

2015-11-23

The U.S. Department of Energy Office of River Protection (ORP) has initiated and leads an integrated Advanced Waste Glass (AWG) program to increase the loading of Hanford tank wastes in glass while meeting melter lifetime expectancies and process, regulatory, and product performance requirements. The integrated ORP program is focused on providing a technical, science-based foundation for making key decisions regarding the successful operation of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) facilities in the context of an optimized River Protection Project (RPP) flowsheet. The fundamental data stemming from this program will support development of advanced glass formulations, keymore » product performance and process control models, and tactical processing strategies to ensure safe and successful operations for both the low-activity waste (LAW) and high-level waste vitrification facilities. These activities will be conducted with the objective of improving the overall RPP mission by enhancing flexibility and reducing cost and schedule.« less

The role of frit in nuclear waste vitrification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vienna, J.D.; Smith, P.A.; Dorn, D.A.

1994-04-01

Vitrification of nuclear waste requires additives which are often vitrified independently to form a frit. Frit composition is formulated to meet the needs of glass composition and processing. The effects of frit on melter feed and melt processing, glass acceptance, and waste loading is of practical interest in understanding the trade-offs associated with the competing demands placed on frit composition. Melter feed yield stress, viscosity and durability of frits and corresponding waste glasses as well as the kinetics of elementary melting processes have been measured. The results illustrate the competing requirements on frit. Four frits (FY91, FY93, HW39-4, and SR202)more » and simulated neutralized current acid waste (NCAW) were used in this study. The experimental evidence shows that optimization of frit for one processing related property often results in poorer performance for the remaining properties. The difficulties associated with maximum waste loading and durability are elucidated for glasses which could be processed using technology available for the previously proposed Hanford Waste Vitrification Plant.« less

Behavior of Aging, Micro-Void, and Self-Healing of Glass/Ceramic Materials and Its Effect on Mechanical Properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Wenning N.; Sun, Xin; Khaleel, Mohammad A.

This chapter first describes tests to investigate the temporal evolution of the volume fraction of ceramic phases, the evolution of micro-damage, and the self-healing behavior of the glass ceramic sealant used in SOFCs, then a phenomenological model based on mechanical analogs is developed to describe the temperature dependent Young’s modulus of glass ceramic seal materials. It was found that after the initial sintering process, further crystallization of the glass ceramic sealant does not stop, but slows down and reduces the residual glass content while boosting the ceramic crystalline content. Under the long-term operating environment, distinct fibrous and needle-like crystals inmore » the amorphous phase disappeared, and smeared/diffused phase boundaries between the glass phase and ceramic phase were observed. Meanwhile, the micro-damage was induced by the cooling-down process from the operating temperature to the room temperature, which can potentially degrade the mechanical properties of the glass/ceramic sealant. The glass/ceramic sealant self-healed upon reheating to the SOFC operating temperature, which can restore the mechanical performance of the glass/ceramic sealant. The phenomenological model developed here includes the effects of continuing aging and devitrification on the ceramic phase volume fraction and the resulted mechanical properties of glass ceramic seal material are considered. The effects of micro-voids and self-healing are also considered using a continuum damage mechanics (CDM) model. The formulation is for glass/ceramic seal in general, and it can be further developed to account for effects of various processing parameters. This model was applied to G18, and the temperature-dependent experimental measurements were used to calibrate the modeling parameters and to validate the model prediction.« less

Toughened uni-piece, fibrous, reinforced, oxidization-resistant composite

NASA Technical Reports Server (NTRS)

Stewart, David A. (Inventor); Leiser, Daniel B. (Inventor)

2008-01-01

A composite thermal protection structure, for applications such as atmospheric re-entry vehicles, that can withstand temperatures as high as 3600.degree. F. The structure includes an exposed surface cap having a specially formulated coating, an insulator base adjacent to the cap with another specially formulated coating, and one or more pins that extend from the cap through the insulator base to tie the cap and base together, through ceramic bonding and mechanical attachment. The cap and insulator base have corresponding depressions and projections that mate and allow for differences in thermal expansion of the cap and base. A thin coating of a reaction cured glass formulation is optionally provided on the structure to allow reduce oxidization and/or to reduce catalytic efficiency.

In vitro dissolution of strontium titanate to estimate clearance rates in human lungs

NASA Astrophysics Data System (ADS)

Anderson, Jeri Lynn

At the In-Tank Precipitation facility (ITP) of the Savannah River Site, strontium and other radionuclides are removed from high-level radioactive waste and sent to the Defense Waste Processing Facility (DWPF). Strontium removal is accomplished by ion-exchange using monosodium titanate slurry which creates a form of strontium titanate with unknown solubility characteristics. In the case of accidental inhalation of a compound containing radioactive strontium, the ICRP, in Publication 66, recommends using default values for rates of absorption into body fluids at the lungs in the absence of reliable human or animal data. The default value depends on whether the absorption is considered to be fast, moderate, or slow (Type F, M, or S). Current dose assessment for an individual upon inadvertent exposure to airborne radioactive strontium assumes that all strontium compounds are Type F (soluble) or Type S (insoluble). Pure high-fired strontium titanate (SrTiOsb3) is considered Type S. The purpose of this project was to determine the solubility of strontium titanate in the form created at the ITP facility. An in vitro dissolution study was done with a precipitate simulant and with several types of strontium titanate and the results were compared. An in vivo study was also performed with high-fired SrTiOsb3 in rats. The data from both studies were used independently to assign the compounds to absorption type based on criteria specified in ICRP 71. Results of the in vitro studies showed that the DWPF simulant should be assigned to Type M and the strontium titanate should be assigned to Type S. It is possible the difference in the DWPF simulant is due to the other chemicals present. Results of the in vivo study verified that SrTiOsb3 should be assigned to Type S. Lung clearance data of SrTiOsb3 from rats showed that 85% cleared within the first 24 hours and the remaining 15% with a half-time of 130 days. The initial rapid clearance is attributed to deposition in airways as compared to the alveolar region.

Wetting and adhesion evaluation of cosmetic ingredients and products: correlation of in vitro-in vivo contact angle measurements.

PubMed

Capra, P; Musitelli, G; Perugini, P

2017-08-01

The aim of this work was to use the contact angle measurement in order to predict the behaviour of ingredients and finished cosmetic products on skin to improve skin feel and product texture. Different classes of cosmetic ingredients and formulations were evaluated. The contact angle measurements were carried out by the sessile drop method using an apparatus, designed and set up in laboratory. Glass, Teflon and human skin were the reference substrates. In a preliminary phase, TEWL parameter, sebum content and hydration of human skin were measured to set up method. Data demonstrated that glass substrate may be used as replacement of the skin:critical surface tension of skin and glass were about of 27 and 31 dyne cm -1 , respectively. Non-ionic surfactant with increasing HLB was evaluated: a correlation between contact angle measured and HLB was not observed because of different and complex molecular structure. In detail, ethylhexyl hydroxystearate (θ glass = 17.1°) showed lower contact angle value with respect to Polysorbate 20 (θ glass = 28.1°). Sodium laureth sulphate and stearalkonium chloride were also evaluated: anionic molecule showed more affinity for glass with respect to Teflon (θ glass = 21.7° and θ Teflon = 52.3°). Lipids and silicones showed different affinity for substrate according to hydrophilic groups and hydrocarbon chain: contact angles of silicones remained unchanged independently from substrate. Finished cosmetic products (O/W, W/O emulsions, cleansing oil, dry skin oil) showed different profiles according to surfactant and its affinity for continuous phase of the formulation. Comparing the values of the contact angle on skin of non-ionic surfactants, as ethylhexyl hydroxystearate and Polysorbate 20, they showed values lower (near to zero) than ones of sodium laureth sulphate and Stearalkonium Chloride (21.7° and 66.8°, respectively). Finally, finished cosmetic products tested on human skin showed different profile: corresponded contact angle values were less than 20°. The product tended to be quickly adsorbed on human skin. Systematic study carried out by evaluating the wettability of single cosmetic ingredients on different substrates allowed to find correlations between the use of certain ingredients and the final performance of a cosmetic product. © 2017 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Potential of Prolamins from Maize and Sorghum to Form Gluten-like Structures in Wheat-free Bread

USDA-ARS?s Scientific Manuscript database

Prolamins from maize (zeins) are known to form viscoelastic, extensible, cohesive dough when mixed together with starch and water above their glass transition temperature (Tg, approximately 28 °C). By adding hydroxypropyl methylcellulose (HPMC, a surface-active hydrocolloid) to this formulation, lea...

Glass-liquid phase separation in highly supersaturated aqueous solutions of telaprevir.

PubMed

Mosquera-Giraldo, Laura I; Taylor, Lynne S

2015-02-02

Amorphous solid dispersions are of great current interest because they can improve the delivery of poorly water-soluble compounds. It has been recently noted that the highly supersaturated solutions generated by dissolution of some ASDs can undergo a phase transition to a colloidal, disordered, drug-rich phase when the concentration exceeds the "amorphous solubility" of the drug. The purpose of this study was to investigate the phase behavior of supersaturated solutions of telaprevir, which is formulated as an amorphous solid dispersion in the commercial product. Different analytical techniques including proton nuclear magnetic resonance spectroscopy (NMR), ultraviolet spectroscopy (UV), fluorescence spectroscopy and flux measurements were used to evaluate the properties of aqueous supersaturated solutions of telaprevir. It was found that highly supersaturated solutions of telaprevir underwent glass-liquid phase separation (GLPS) when the concentration exceeded 90 μg/mL, forming a water-saturated colloidal, amorphous drug-rich phase with a glass transition temperature of 52 °C. From flux measurements, it was observed that the "free" drug concentration reached a maximum at the concentration where GLPS occurred, and did not increase further as the concentration was increased. This phase behavior, which results in a precipitate and a metastable equilibrium between a supersaturated solution and a drug-rich phase, is obviously important in the context of evaluating amorphous solid dispersion formulations and their crystallization routes.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ebert, W. L.; Snyder, C. T.; Frank, Steven

This report describes the scientific basis underlying the approach being followed to design and develop “advanced” glass-bonded sodalite ceramic waste form (ACWF) materials that can (1) accommodate higher salt waste loadings than the waste form developed in the 1990s for EBR-II waste salt and (2) provide greater flexibility for immobilizing extreme waste salt compositions. This is accomplished by using a binder glass having a much higher Na 2O content than glass compositions used previously to provide enough Na+ to react with all of the Cl– in the waste salt and generate the maximum amount of sodalite. The phase compositions andmore » degradation behaviors of prototype ACWF products that were made using five new binder glass formulations and with 11-14 mass% representative LiCl/KCl-based salt waste were evaluated and compared with results of similar tests run with CWF products made using the original binder glass with 8 mass% of the same salt to demonstrate the approach and select a composition for further studies. About twice the amount of sodalite was generated in all ACWF materials and the microstructures and degradation behaviors confirmed our understanding of the reactions occurring during waste form production and the efficacy of the approach. However, the porosities of the resulting ACWF materials were higher than is desired. These results indicate the capacity of these ACWF waste forms to accommodate LiCl/KCl-based salt wastes becomes limited by porosity due to the low glass-to-sodalite volume ratio. Three of the new binder glass compositions were acceptable and there is no benefit to further increasing the Na content as initially planned. Instead, further studies are needed to develop and evaluate alternative production methods to decrease the porosity, such as by increasing the amount of binder glass in the formulation or by processing waste forms in a hot isostatic press. Increasing the amount of binder glass to eliminate porosity will decrease the waste loading from about 12% to 10% on a mass basis, but this will not significantly impact the waste loading on a volume basis. It is likely that heat output will limit the amount of waste salt that can be accommodated in a waste canister rather than the salt loading in an ACWF, and that the increase from 8 mass% to about 10 mass% salt loadings in ACWF materials will be sufficient to optimize these waste forms. Although the waste salt composition used in this study contained a moderate amount of NaCl, the test results suggest waste salts with little or no NaCl can be accommodated in ACWF materials by using the new binder glass, albeit at waste loadings lower than 8 mass%. The higher glass contents that will be required for ACWF materials made with salt wastes that do not contain NaCl are expected to result in much lower porosities in those waste forms.« less

Kinetics of Cold-Cap Reactions for Vitrification of Nuclear Waste Glass Based on Simultaneous Differential Scanning Calorimetry - Thermogravimetry (DSC-TGA) and Evolved Gas Analysis (EGA)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodriguez, Carmen P.; Pierce, David A.; Schweiger, Michael J.

2013-12-03

For vitrifying nuclear waste glass, the feed, a mixture of waste with glass-forming and modifying additives, is charged onto the cold cap that covers 90-100% of the melt surface. The cold cap consists of a layer of reacting molten glass floating on the surface of the melt in an all-electric, continuous glass melter. As the feed moves through the cold cap, it undergoes chemical reactions and phase transitions through which it is converted to molten glass that moves from the cold cap into the melt pool. The process involves a series of reactions that generate multiple gases and subsequent massmore » loss and foaming significantly influence the mass and heat transfers. The rate of glass melting, which is greatly influenced by mass and heat transfers, affects the vitrification process and the efficiency of the immobilization of nuclear waste. We studied the cold-cap reactions of a representative waste glass feed using both the simultaneous differential scanning calorimetry thermogravimetry (DSC-TGA) and the thermogravimetry coupled with gas chromatography-mass spectrometer (TGA-GC-MS) as complementary tools to perform evolved gas analysis (EGA). Analyses from DSC-TGA and EGA on the cold-cap reactions provide a key element for the development of an advanced cold-cap model. It also helps to formulate melter feeds for higher production rate.« less

Final Report - "Foaming and Antifoaming and Gas Entrainment in Radioactive Waste Pretreatment and Immobilization Processes"

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wasan, Darsh T.

2007-10-09

The Savannah River Site (SRS) and Hanford site are in the process of stabilizing millions of gallons of radioactive waste slurries remaining from production of nuclear materials for the Department of Energy (DOE). The Defense Waste Processing Facility (DWPF) at SRS is currently vitrifying the waste in borosilicate glass, while the facilities at the Hanford site are in the construction phase. Both processes utilize slurry-fed joule-heated melters to vitrify the waste slurries. The DWPF has experienced difficulty during operations. The cause of the operational problems has been attributed to foaming, gas entrainment and the rheological properties of the process slurries.more » The rheological properties of the waste slurries limit the total solids content that can be processed by the remote equipment during the pretreatment and meter feed processes. Highly viscous material can lead to air entrainment during agitation and difficulties with pump operations. Excessive foaming in waste evaporators can cause carryover of radionuclides and non-radioactive waste to the condensate system. Experimental and theoretical investigations of the surface phenomena, suspension rheology and bubble generation of interactions that lead to foaming and air entrainment problems in the DOE High Level and Low Activity Radioactive Waste separation and immobilization processes were pursued under this project. The first major task accomplished in the grant proposal involved development of a theoretical model of the phenomenon of foaming in a three-phase gas-liquid-solid slurry system. This work was presented in a recently completed Ph.D. thesis (9). The second major task involved the investigation of the inter-particle interaction and microstructure formation in a model slurry by the batch sedimentation method. Both experiments and modeling studies were carried out. The results were presented in a recently completed Ph.D. thesis. The third task involved the use of laser confocal microscopy to study the effectiveness of three slurry rheology modifiers. An effective modifier was identified which resulted in lowering the yield stress of the waste simulant. Therefore, the results of this research have led to the basic understanding of the foaming/antifoaming mechanism in waste slurries as well as identification of a rheology modifier, which enhances the processing throughput, and accelerates the DOE mission. The objectives of this research effort were to develop a fundamental understanding of the physico-chemical mechanisms that produced foaming and air entrainment in the DOE High Level (HLW) and Low Activity (LAW) radioactive waste separation and immobilization processes, and to develop and test advanced antifoam/defoaming/rheology modifier agents. Antifoams/rheology modifiers developed from this research ere tested using non-radioactive simulants of the radioactive wastes obtained from Hanford and the Savannah River Site (SRS).« less

Composite bone cements loaded with a bioactive and ferrimagnetic glass-ceramic: Leaching, bioactivity and cytocompatibility.

PubMed

Verné, Enrica; Bruno, Matteo; Miola, Marta; Maina, Giovanni; Bianco, Carlotta; Cochis, Andrea; Rimondini, Lia

2015-08-01

In this work, composite bone cements, based on a commercial polymethylmethacrylate matrix (Palamed®) loaded with ferrimagnetic bioactive glass-ceramic particles (SC45), were produced and characterized in vitro. The ferrimagnetic bioactive glass-ceramic belongs to the system SiO2-Na2O-CaO-P2O5-FeO-Fe2O3 and contains magnetite (Fe3O4) crystals into a residual amorphous bioactive phase. Three different formulations (containing 10, 15 and 20 wt.% of glass-ceramic particles respectively) have been investigated. These materials are intended to be applied as bone fillers for the hyperthermic treatment of bone tumors. The morphological, compositional, calorimetric and mechanical properties of each formulation have been already discussed in a previous paper. The in vitro properties of the composite bone cements described in the present paper are related to iron ion leaching test (by graphite furnace atomic absorption spectrometer), bioactivity (i.e. the ability to stimulate the formation of a hydroxyapatite - HAp - layer on their surface after soaking in simulated body fluid SBF) and cytocompatibility toward human osteosarcoma cells (ATCC CRL-1427, Mg63). Morphological and chemical characterizations by scanning electron microscopy and energy dispersion spectrometry have been performed on the composite samples after each test. The iron release was negligible and all the tested samples showed the growth of HAp on their surface after 28 days of immersion in a simulated body fluid (SBF). Cells showed good viability, morphology, adhesion, density and the ability to develop bridge-like structures on all investigated samples. A synergistic effect between bioactivity and cell mineralization was also evidenced. Copyright © 2015 Elsevier B.V. All rights reserved.

The role of Sr2+ on the structure and reactivity of SrO-CaO-ZnO-SiO2 ionomer glasses.

PubMed

Boyd, Daniel; Towler, Mark R; Watts, Sally; Hill, Robert G; Wren, Anthony W; Clarkin, Owen M

2008-02-01

The suitability of Glass Polyalkenoate Cements (GPCs) for use in orthopaedics is retarded by the presence in the glass phase of aluminium, a neurotoxin. Unfortunately, the aluminium ion plays an integral role in the setting process of GPCs and its absence is likely to hinder cement formation. However, the authors have previously shown that aluminium free GPCs may be formulated based on calcium zinc silicate glasses and these novel materials exhibit significant potential as hard tissue biomaterials. To further improve their potential, and given that Strontium (Sr) based drugs have had success in the treatment of osteoporosis, the authors have substituted Calcium (Ca) with Sr in the glass phase of a series of aluminium free GPCs. However to date little data exists on the effect SrO has on the structure and reactivity of SrO-CaO-ZnO-SiO(2) glasses. The objective of this work was to characterise the effect of the Ca/Sr substitution on the structure of such glasses, and evaluate the subsequent reactivity of these glasses with an aqueous solution of Polyacrylic acid (PAA). To this end (29)Si MAS-NMR, differential scanning calorimetry (DSC), X-ray diffraction, and network connectivity calculations, were used to characterize the structure of four strontium calcium zinc silicate glasses. Following glass characterization, GPCs were produced from each glass using a 40 wt% solution of PAA (powder:liquid = 2:1.5). The working times and setting times of the GPCs were recorded as per International standard ISO9917. The results acquired as part of this research indicate that the substitution of Ca for Sr in the glasses examined did not appear to significantly affect the structure of the glasses investigated. However it was noted that increasing the amount of Ca substituted for Sr did result in a concomitant increase in setting times, a feature that may be attributable to the higher basicity of SrO over CaO.

Aggregation and Particle Formation of Therapeutic Proteins in Contact With a Novel Fluoropolymer Surface Versus Siliconized Surfaces: Effects of Agitation in Vials and in Prefilled Syringes.

PubMed

Teska, Brandon M; Brake, Jeffrey M; Tronto, Gregory S; Carpenter, John F

2016-07-01

We examined the effects of an accelerated agitation protocol on 2 protein therapeutics, intravenous immunoglobulin (IVIG) and Avastin (bevacizumab), in contact with a novel fluoropolymer surface and more typical siliconized surfaces. The fluoropolymer surface provides "solid-phase" lubrication for the syringe plunger-obviating the need for silicone oil lubrication in prefilled syringes. We tested the 2 surfaces in a vial system and in prefilled glass syringes. We also examined the effects of 2 buffers, phosphate-buffered saline (PBS) and 0.2-M glycine, with and without the addition of polysorbate 20, on agitation-induced aggregation of IVIG. Aggregation was monitored by measuring subvisible particle formation and soluble protein loss. In both vials and syringes, protein particle formation was much lower during agitation with the fluoropolymer surface than with the siliconized surface. Also, particle formation was greater in PBS than in glycine buffer, an effect attributed to lower colloidal stability of IVIG in PBS. Polysorbate 20 in the formulation greatly inhibited protein particle formation. Overall, the fluoropolymer plunger surface in an unsiliconized glass barrel was demonstrated to be a viable solution for eliminating silicone oil droplets from prefilled syringe formulations and providing a consistent system for rationale formulation development and simplified particle analysis. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Irradiation effect of low-energy ion on polyurethane nanocoating containing metal oxide nanoparticles

NASA Astrophysics Data System (ADS)

Verma, Jaya; Nigam, Subhasha; Sinha, Surbhi; Sikarwar, B. S.; Bhattacharya, Arpita

2017-12-01

Irradiation effect of low-energy ion beam has been investigated on nanocoating developed with silica, titania and silica-titania core-shell nanoparticles embedded in an organic binder for nanopaint application. In this work, we have taken polyurethane as a model organic binder. Silica nanoparticles have been prepared through sol-gel synthesis with a particle size of 85 nm. Titania and core-shell nanoparticles have been prepared through both sol-gel and peptization process. Particle sizes obtained were 107 nm for titania and 240 nm for core-shell nanoparticles prepared through sol-gel process and 75 nm for TiO2 and 144 nm for core-shell nanoparticles prepared through peptization process. The coating formulations were developed with the above nanoparticles individually and nanoparticle concentration was varied from 1 to 6 wt% and the best performance in terms of hydrophobicity was obtained with 4 wt % of the nanoparticles in polyurethane coating formulation. All the coating formulations prepared were applied on a glass substrate and dried at 100°C. The dry film thickness obtained was around 100 µm in each case. These films dried on glass substrate were irradiated by nitrogen and argon ion beam with energy of 26 keV at fluences of 1014 to 1016 ions/cm2. The anti-algal property of the irradiated samples was improved and hydrophobicity was reduced.

Iron Phosphate Glass-Containing Hanford Waste Simulant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sevigny, Gary J.; Kimura, Marcia L.; Fischer, Christopher M.

2012-01-18

Resolution of the nation's high-level tank waste legacy requires the design, construction, and operation of large and technically complex one-of-a-kind processing waste treatment and vitrification facilities. While the ultimate limits for waste loading and melter efficiency have yet to be defined or realized, significant reductions in glass volumes for disposal and mission life may be possible with advancements in melter technologies and/or glass formulations. This test report describes the experimental results from a small-scale test using the research-scale melter (RSM) at Pacific Northwest National Laboratory (PNNL) to demonstrate the viability of iron-phosphate-based glass with a selected waste composition that ismore » high in sulfate (4.37 wt% SO3). The primary objective of the test was to develop data to support a cost-benefit analysis related to the implementation of phosphate-based glasses for Hanford low-activity waste (LAW) and/or other high-level waste streams within the U.S. Department of Energy complex. The testing was performed by PNNL and supported by Idaho National Laboratory, Savannah River National Laboratory, Missouri University of Science and Technology, and Mo-Sci Corporation.« less

Diametral and compressive strength of dental core materials.

PubMed

Cho, G C; Kaneko, L M; Donovan, T E; White, S N

1999-09-01

Strength greatly influences the selection of core materials. Many disparate material types are now recommended for use as cores. Cores must withstand forces due to mastication and parafunction for many years. This study compared the compressive and diametral tensile strengths of 8 core materials of various material classes and formulations (light-cured hybrid composite, autocured titanium containing composite, amalgam, glass ionomer, glass ionomer cermet, resin-modified glass ionomer, and polyurethane). Materials were manipulated according to manufacturers' instructions for use as cores. Mean compressive and diametral strengths with associated standard errors were calculated for each material (n = 10). Analyses of variance were computed (P <.0001) and multiple comparisons tests discerned many differences among materials. Compressive strengths varied widely from 61.1 MPa for a polyurethane to 250 MPa for a resin composite. Diametral tensile strengths ranged widely from 18.3 MPa for a glass ionomer cermet to 55.1 MPa for a resin composite. Some resin composites had compressive and tensile strengths equal to those of amalgam. Light-cured hybrid resin composites were stronger than autocured titanium containing composites. The strengths of glass ionomer-based materials and of a polyurethane material were considerably lower than for resin composites or amalgam.

Calorimetric analysis of cryopreservation and freeze-drying formulations.

PubMed

Sun, Wendell Q

2015-01-01

Differential scanning calorimetry (DSC) is a commonly used thermal analysis technique in cryopreservation and freeze-drying research. It has been used to investigate crystallization, eutectic formation, glass transition, devitrification, recrystallization, melting, polymorphism, molecular relaxation, phase separation, water transport, thermochemistry, and kinetics of complex reactions (e.g., protein denaturation). Such information can be used for the optimization of protective formulations and process protocols. This chapter gives an introduction to beginners who are less familiar with this technique. It covers the instrument and its basic principles, followed by a discussion of the methods as well as examples of specific applications.

Results Of Hg Speciation Testing On DWPF SMECT-1, SMECT-3, And SMECT-5 Samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C.

2016-01-07

The Savannah River National Laboratory (SRNL) was tasked with preparing and shipping samples for Hg speciation by Eurofins Frontier Global Sciences, Inc. in Seattle, WA on behalf of the Savannah River Remediation (SRR) Mercury Task Team. The thirteenth shipment of samples was designated to include Defense Waste Processing Facility (DWPF) Slurry Mix Evaporator Condensate Tank (SMECT) from Sludge Receipt and Adjustment Tank (SRAT) Batch 736 and 738 samples. Triplicate samples of each material were prepared for this shipment. Each replicate was analyzed for seven Hg species: total Hg, total soluble (dissolved) Hg, elemental Hg [Hg(0)], ionic (inorganic) Hg [Hg(I) andmore » Hg(II)], methyl Hg [CH 3Hg-X, where X is a counter anion], ethyl Hg [CH 3CH 2-Hg-X, where X is a counter anion], and dimethyl Hg [(CH 3) 2Hg]. The difference between the total Hg and total soluble Hg measurements gives the particulate Hg concentration, i.e. Hg adsorbed to the surface of particulate matter in the sample but without resolution of the specific adsorbed species. The average concentrations of Hg species in the aqueous samples derived from Eurofins reported data corrected for dilutions performed by SRNL are tabulated.« less

Inhibition Of Washed Sludge With Sodium Nitrite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Congdon, J. W.; Lozier, J. S.

2012-09-25

This report describes the results of electrochemical tests used to determine the relationship between the concentration of the aggressive anions in washed sludge and the minimum effective inhibitor concentration. Sodium nitrate was added as the inhibitor because of its compatibility with the DWPF process. A minimum of 0.05M nitrite is required to inhibit the washed sludge simulant solution used in this study. When the worst case compositions and safety margins are considered, it is expected that a minimum operating limit of nearly 0.1M nitrite will be specified. The validity of this limit is dependent on the accuracy of the concentrationsmore » and solubility splits previously reported. Sodium nitrite additions to obtain 0.1M nitrite concentrations in washed sludge will necessitate the additional washing of washed precipitate in order to decrease its sodium nitrite inhibitor requirements sufficiently to remain below the sodium limits in the feed to the DWPF. Nitrite will be the controlling anion in "fresh" washed sludge unless the soluble chloride concentration is about ten times higher than predicted by the solubility splits. Inhibition of "aged" washed sludge will not be a problem unless significant chloride dissolution occurs during storage. It will be very important tomonitor the composition of washed sludge during processing and storage.« less

Hydrogen Production in Radioactive Solutions in the Defense Waste Processing Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

CRAWFORD, CHARLES L.

2004-05-26

In the radioactive slurries and solutions to be processed in the Defense Waste Processing Facility (DWPF), hydrogen will be produced continuously by radiolysis. This production results from alpha, beta, and gamma rays from decay of radionuclides in the slurries and solutions interacting with the water. More than 1000 research reports have published data concerning this radiolytic production. The results of these studies have been reviewed in a comprehensive monograph. Information about radiolytic hydrogen production from the different process tanks is necessary to determine air purge rates necessary to prevent flammable mixtures from accumulating in the vapor spaces above these tanks.more » Radiolytic hydrogen production rates are usually presented in terms of G values or molecules of hydrogen produced per 100ev of radioactive decay energy absorbed by the slurry or solution. With the G value for hydrogen production, G(H2), for a particular slurry and the concentrations of radioactive species in that slurry, the rate of H2 production for that slurry can be calculated. An earlier investigation estimated that the maximum rate that hydrogen could be produced from the sludge slurry stream to the DWPF is with a G value of 0.45 molecules per 100ev of radioactive decay energy sorbed by the slurry.« less

COOL ROOF COATINGS INCORPORATING GLASS HOLLOW MICROSPHERES FOR IMPROVED SOLAR REFLECTANCE

EPA Science Inventory

Elastomeric cool-roof coatings can be applied to buildings to decrease heat gain, yielding energy savings and mitigating the “urban heat island” effect. Most cool-roof formulations are based on titanium dioxide (TiO₂). While TiO₂ and several TiO₂

Matt waste from glass separated collection: an eco-sustainable addition for new building materials.

PubMed

Bignozzi, M C; Saccani, A; Sandrolini, F

2009-01-01

Matt waste (MW), a by-product of purification processes of cullet derived from separated glass waste collection, has been studied as filler for self-compacting concrete and as an addition for newly blended cement. Properties of self-compacting concrete compared to reference samples are reported. They include characteristics at the fresh and hardened states, and the compressive strength and porosity of mortar samples that were formulated with increasing amounts of MW to be used as cement replacement (up to 50wt.%). The effects of matt waste are discussed with respect to the mechanical and microstructural characteristics of the resulting new materials.

Marshall Convergent Spray Formulation Improvement for High Temperatures

NASA Technical Reports Server (NTRS)

Scarpa, Jack; Patterson,Chat

2011-01-01

The Marshall Convergent Coating-1 (MCC-1) formulation was produced in the 1990s, and uses a standard bisphenol A epoxy resin system with a triamine accelerator. With the increasing heat rates forecast for the next generation of vehicles, higher-temperature sprayable coatings are needed. This work substitutes the low-temperature epoxy resins used in the MCC-1 coating with epoxy phenolic, epoxy novalac, or resorcinolinic resins (higher carbon content), which will produce a higher char yield upon exposure to high heat and increased glass transition temperature. High-temperature filler materials, such as granular cork and glass ecospheres, are also incorporated as part of the convergent spray process, but other sacrificial (ablative) materials are possible. In addition, the use of polyhedral oligomeric silsesquioxanes (POSS) nanoparticle hybrids will increase both reinforcement aspects and contribute to creating a tougher silacious char, which will reduce recession at higher heat rates. Use of expanding epoxy resin (lightweight MCC) systems are also useful in that they reduce system weight, have greater insulative properties, and a decrease in application times can be realized.

A new brominated polymeric additive for flame retardant glass-filled polybutylene terephthalate

NASA Technical Reports Server (NTRS)

Nir, Z.; Kourtides, D. A.; Parker, J. A.; Bar-Yaacov, Y.; Minke, R.; Touval, I.

1982-01-01

Attention is called to the undesirable effects (poor ultraviolet light stability and blooming) sometimes introduced by brominated flame retarders. A brominated polymeric additive (BPA) with little or none of these undesirable side effects is compared with decabromobiphenyl oxide (DBBPO). The additive bears the product name F-2300. It is found to be more easily dispersed than DBBPO. The F-2300 is as effective as the DBBPO in the oxygen index test. The improved efficiency of the F-2300 may be explained by its better dispersion in polybutylene terephthalate (PBT). Glass-filled PBT containing F-2300 is found to be more resistant to UV degradation than DBBPO-containing formulas. Formulations with F-2300 therefore have a longer useful outdoor life. F-2300 is a diglycidyl-type polymer containing 50 percent aromatically bound bromine. Its melting point is 112 C, and it is stable up to 372 C. It is pointed out that since its melts at a relatively low temperature, it can be introduced into the formulation as a large agglomerate and still be dispersed evenly throughout the polymer.

Power Law Versus Exponential Form of Slow Crack Growth of Advanced Structural Ceramics: Dynamic Fatigue

NASA Technical Reports Server (NTRS)

Choi, Sung R.; Gyekenyesi, John P.

2002-01-01

The life prediction analysis based on an exponential crack velocity formulation was examined using a variety of experimental data on glass and advanced structural ceramics in constant stress-rate ("dynamic fatigue") and preload testing at ambient and elevated temperatures. The data fit to the strength versus In (stress rate) relation was found to be very reasonable for most of the materials. It was also found that preloading technique was equally applicable for the case of slow crack growth (SCG) parameter n > 30. The major limitation in the exponential crack velocity formulation, however, was that an inert strength of a material must be known priori to evaluate the important SCG parameter n, a significant drawback as compared to the conventional power-law crack velocity formulation.

Investigating the Crystallization Propensity of Structurally Similar Organic Molecules From Amorphous State

NASA Astrophysics Data System (ADS)

Kalra, Arjun

Combinatorial chemistry and high-throughput screening approaches utilized during drug discovery have resulted in many potent pharmacologically active molecules with low aqueous solubility and consequently poor bioavailability. Enabling technologies, such as amorphous solid dispersions (ASD's), can obviate these challenges and provide an efficient route to formulate the drug as an oral solid dosage form. However, high-energy amorphous materials have an inherent tendency to crystallize and in doing so can negate the apparent solubility advantage achieved by using such formulations. Crystallization can occur during (1) cooling the drug molecule from the melt state (such as during hot melt extrusion); (2) during storage of an amorphous formulation; (3) during pharmaceutical processing unit operations such as compression, granulation etc. Current knowledge with regards to the relationship between crystallization propensity of an active pharmaceutical ingredient (API) from the amorphous state (supercooled liquid and glass) and its thermodynamic, kinetic and molecular properties is limited. Furthermore, examining the mechanistic steps involved in crystallization of organic molecules under conditions of supercooling provides an opportunity to examine supramolecular aggregation events occurring during early stages of crystallization. Studying crystallization mechanism from amorphous state is important for pharmaceutical formulation development because a molecular-level understanding of the crystallization process would provide clues regarding the intermolecular interactions at the early stages of nucleation and help in rational selection of polymeric excipients to hinder such events. The primary goal of this research is to develop an understanding of phase transition from amorphous pharmaceuticals, specifically focusing on the role of thermodynamic, kinetic and molecular properties of a series of structurally similar compounds. It is hypothesized that the there exists a link between thermodynamics quantities, kinetic properties, molecular interactions and glass forming ability. Furthermore, it is hypothesized that the molecular heterogeneity in supercooled liquids and glassy state, manifested through intermolecular interactions and conformational flexibility impacts the observed crystallization behavior. Understanding the phase transition kinetics and mechanism of crystallization from amorphous pharmaceuticals is critical for development of stable formulations for drug delivery. The specific goals of this research include: (1) Investigating the link between thermodynamic and kinetic factors affecting the crystallization propensity of organic compounds from supercooled liquid state. (2) Evaluating the role of intermolecular interactions and conformational distribution on glass forming ability and stability. (3) Examining the relationship between supramolecular aggregates present in glassy state and polymorphic outcome. It is believed that successful completion of this research will provide a fundamental understanding of amorphous solid-state chemistry as well as provide useful tools for the implementation of ASD's as solid oral dosage forms.

X-ray absorption studies of chlorine valence and local environments in borosilicate waste glasses

NASA Astrophysics Data System (ADS)

McKeown, David A.; Gan, Hao; Pegg, Ian L.; Stolte, W. C.; Demchenko, I. N.

2011-01-01

Chlorine (Cl) is a constituent of certain types of nuclear wastes and its presence can affect the physical and chemical properties of silicate melts and glasses developed for the immobilization of such wastes. Cl K-edge X-ray absorption spectra (XAS) were collected and analyzed to characterize the unknown Cl environments in borosilicate waste glass formulations, ranging in Cl-content from 0.23 to 0.94 wt.%. Both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) data for the glasses show trends dependent on calcium (Ca) content. Near-edge data for the Ca-rich glasses are most similar to the Cl XANES of CaCl 2, where Cl - is coordinated to three Ca atoms, while the XANES for the Ca-poor glasses are more similar to the mineral davyne, where Cl is most commonly coordinated to two Ca in one site, as well as Cl and oxygen nearest-neighbors in other sites. With increasing Ca content in the glass, Cl XANES for the glasses approach that for CaCl 2, indicating more Ca nearest-neighbors around Cl. Reliable structural information obtained from the EXAFS data for the glasses is limited, however, to Cl sbnd Cl, Cl sbnd O, and Cl sbnd Na distances; Cl sbnd Ca contributions could not be fit to the glass data, due to the narrow k-space range available for analysis. Structural models that best fit the glass EXAFS data include Cl sbnd Cl, Cl sbnd O, and Cl sbnd Na correlations, where Cl sbnd O and Cl sbnd Na distances decrease by approximately 0.16 Å as glass Ca content increases. XAS for the glasses indicates Cl - is found in multiple sites where most Cl-sites have Ca neighbors, with oxygen, and possibly, Na second-nearest neighbors. EXAFS analyses suggest that Cl sbnd Cl environments may also exist in the glasses in minor amounts. These results are generally consistent with earlier findings for silicate glasses, where Cl - was associated with Ca 2+ and Na + in network modifier sites.

Dielectric spectroscopy for the determination of the glass transition temperature of pharmaceutical solid dispersions.

PubMed

O'Donnell, Kevin P; Woodward, W H Hunter

2015-06-01

The purpose of this study was to evaluate analytical techniques for the measurement of the glass transition temperature of HPMC and formulated solid dispersions thereof. Unmodified samples of various grades of HPMC and solid dispersions of HPMC and itraconazole produced by hot melt extrusion were analyzed by thermomechanical analysis, differential scanning calorimetry, thermally stimulated depolarization current and dielectric spectroscopy. It was found that dielectric spectroscopy offers the best accuracy and reproducibility for analysis of the base HPMC powders regardless of the substitution type or viscosity grade and that the obtained results were not frequency dependent. The results of dielectric measurements of solid dispersions prepared by hot melt extrusion were compared with predicted values of the Gordon-Taylor equation. It was found that time-temperature superposition effects and small molecule frequency dependence makes broadly applying determination of the glass transition temperature in drug dispersions by dielectric spectroscopy prohibitively difficult.

Preliminary evaluation of Glass Resin materials for solar cell cover use

NASA Technical Reports Server (NTRS)

Marsik, S. J.; Swartz, C. K.; Baraona, C. R.

1978-01-01

The glass resins were deposited by several techniques on 200 micron thick cells and on 50 microns thick wafers. The covered cells were exposed to ultraviolet light in vacuum to an intensity of 10 UV energy-equivalent solar constants at air mass zero for 728 hr. The exposure was followed by a single long thermal cycle from ambient temperature to -150 C. Visual inspection of the samples indicated that all samples had darkened to varying degrees. The loss in short-circuit current was found to range from 8 to 24%, depending on the resin formulation. In another test over 40 glass resin-coated silicon wafers withstood 15 thermal cycles from 100 to-196 C in one or more of the thicknesses tested. Several of the resin-coated wafers were tested at 65 C and 90% relative humidity for 170 hr. No change in physical appearance was detected.

Final Report - IHLW PCT, Spinel T1%, Electrical Conductivity, and Viscosity Model Development, VSL-07R1240-4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, Albert A.; Piepel, Gregory F.; Landmesser, S. M.

2013-11-13

This report is the last in a series of currently scheduled reports that presents the results from the High Level Waste (HLW) glass formulation development and testing work performed at the Vitreous State Laboratory (VSL) of the Catholic University of America (CUA) and the development of IHLW property-composition models performed jointly by Pacific Northwest National Laboratory (PNNL) and VSL for the River Protection Project-Waste Treatment and Immobilization Plant (RPP-WTP). Specifically, this report presents results of glass testing at VSL and model development at PNNL for Product Consistency Test (PCT), one-percent crystal fraction temperature (T1%), electrical conductivity (EC), and viscosity ofmore » HLW glasses. The models presented in this report may be augmented and additional validation work performed during any future immobilized HLW (IHLW) model development work. Completion of the test objectives is addressed.« less

Glass Polyalkenoate Cements Designed for Cranioplasty Applications: An Evaluation of Their Physical and Mechanical Properties

PubMed Central

Khader, Basel A.; Curran, Declan J.; Peel, Sean; Towler, Mark R.

2016-01-01

Glass polyalkenoate cements (GPCs) have potential for skeletal cementation. Unfortunately, commercial GPCs all contain, and subsequently release, aluminum ions, which have been implicated in degenerative brain disease. The purpose of this research was to create a series of aluminum-free GPCs constructed from silicate (SiO2), calcium (CaO), zinc (ZnO) and sodium (Na2O)-containing glasses mixed with poly-acrylic acid (PAA) and to evaluate the potential of these cements for cranioplasty applications. Three glasses were formulated based on the SiO2-CaO-ZnO-Na2O parent glass (KBT01) with 0.03 mol % (KBT02) and 0.06 mol % (KBT03) germanium (GeO2) substituted for ZnO. Each glass was then mixed with 50 wt % of a patented SiO2-CaO-ZnO-strontium (SrO) glass composition and the resultant mixtures were subsequently reacted with aqueous PAA (50 wt % addition) to produce three GPCs. The incorporation of Ge in the glass phase was found to result in decreased working (142 s to 112 s) and setting (807 s to 448 s) times for the cements manufactured from them, likely due to the increase in crosslink formation between the Ge-containing glasses and the PAA. Compressive (σc) and biaxial flexural (σf) strengths of the cements were examined at 1, 7 and 30 days post mixing and were found to increase with both maturation and Ge content. The bonding strength of a titanium cylinder (Ti) attached to bone by the cements increased from 0.2 MPa, when placed, to 0.6 MPa, after 14 days maturation. The results of this research indicate that Germano-Silicate based GPCs have suitable handling and mechanical properties for cranioplasty fixation. PMID:27023623

Theoretical Considerations of the Prigogine-Defay Ration with Regard to the Glass-Forming Ability of Drugs from Undercooled Melts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wyttenbach, Nicole; Kirchmeyer, Wiebke; Alsenz, Jochem

Drug behavior in undercooled melts is highly important for pharmaceutics with regard to amorphous solid dispersions, and therefore, categories were recently introduced that differentiate glass formers (GFs) from other drugs that are nonglass formers (nGFs). The present study is based on the assumption that molecular properties relevant for the so-called Prigogine–Defay (PD) ratio would be indicative of a drug’s glass-forming ability. The PD ratio depends in theory on the entropy of fusion and molar volume. Experimental data were gathered from a broad set of pharmaceutical compounds (n = 54) using differential scanning calorimetry. The obtained entropy of fusion and molarmore » volume were indeed found to significantly discriminate GFs from nGFs. In a next step, the entropy of fusion was predicted by different in silico methods. A first group contribution method provided rather unreliable estimates for the entropy of fusion, while an alternative in silico approach seemed more promising for drug categorization. Thus, a significant discrimination model employed molar volume, a so-called effective hydrogen bond number, and effective number of torsional bonds (or torsional units) to categorize GFs and nGFs (p ≤ 0.0000). The results led to new insights into drug vitrification and to practical rules of thumb. The latter may serve as guidance in pharmaceutical profiling and early formulation development with respect to amorphous drug formulations.« less

A Review of Iron Phosphate Glasses and Recommendations for Vitrifying Hanford Waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delbert E. Ray; Chandra S. Ray

2013-11-01

This report contains a comprehensive review of the research conducted, world-wide, on iron phosphate glass over the past ~30 years. Special attention is devoted to those iron phosphate glass compositions which have been formulated for the purpose of vitrifying numerous types of nuclear waste, with special emphasis on the wastes stored in the underground tanks at Hanford WA. Data for the structural, chemical, and physical properties of iron phosphate waste forms are reviewed for the purpose of understanding their (a) outstanding chemical durability which meets all current DOE requirements, (b) high waste loadings which can exceed 40 wt% (up tomore » 75 wt%) for several Hanford wastes, (c) low melting temperatures, can be as low as 900°C for certain wastes, and (d) high tolerance for “problem” waste components such as sulfates, halides, and heavy metals (chromium, actinides, noble metals, etc.). Several recommendations are given for actions that are necessary to smoothly integrate iron phosphate glass technology into the present waste treatment plans and vitrification facilities at Hanford.« less

Semiautomated Sample Preparation for Protein Stability and Formulation Screening via Buffer Exchange.

PubMed

Ying, William; Levons, Jaquan K; Carney, Andrea; Gandhi, Rajesh; Vydra, Vicky; Rubin, A Erik

2016-06-01

A novel semiautomated buffer exchange process workflow was developed to enable efficient early protein formulation screening. An antibody fragment protein, BMSdab, was used to demonstrate the workflow. The process afforded 60% to 80% cycle time and scientist time savings and significant material efficiencies. These efficiencies ultimately facilitated execution of this stability work earlier in the drug development process, allowing this tool to inform the developability of potential candidates for development from a formulation perspective. To overcome the key technical challenges, the protein solution was buffer-exchanged by centrifuge filtration into formulations for stability screening in a 96-well plate with an ultrafiltration membrane, leveraging automated liquid handling and acoustic volume measurements to allow several cycles of exchanges. The formulations were transferred into a vacuum manifold and sterile filtered into a rack holding 96 glass vials. The vials were sealed with a capmat of individual caps and placed in stability stations. Stability of the samples prepared by this process and by the standard process was demonstrated to be comparable. This process enabled screening a number of formulations of a protein at an early pharmaceutical development stage with a short sample preparation time. © 2015 Society for Laboratory Automation and Screening.

Stabilization of a Recombinant Ricin Toxin A Subunit Vaccine through Lyophilization

PubMed Central

Hassett, Kimberly J.; Cousins, Megan C.; Rabia, Lilia A.; Chadwick, Chrystal M.; O’Hara, Joanne M.; Nandi, Pradyot; Brey, Robert N.; Mantis, Nicholas J.; Carpenter, John F.; Randolph, Theodore W.

2013-01-01

Lyophilization was used to prepare dry, glassy solid vaccine formulations of recombinant ricin toxin A-chain containing suspensions of colloidal aluminum hydroxide adjuvant. Four lyophilized formulations were prepared by using combinations of rapid or slow cooling during lyophilization and one of two buffers, histidine or ammonium acetate. Trehalose was used as the stabilizing excipient. Aggregation of the colloidal aluminum hydroxide suspension was reduced in formulations processed with a rapid cooling rate. Aluminum hydroxide particle size distributions, glass transition temperatures, water contents, and immunogenicities of lyophilized vaccines were independent of incubation time at 40°C for up to 15 weeks. Mice immunized with reconstituted ricin toxin subunit A (RTA) vaccines produced RTA-specific antibodies and toxin-neutralizing antibodies (TNA) regardless of the length of high temperature vaccine storage or the degree of aluminum adjuvant aggregation that occurred during lyophilization. In murine studies, lyophilized formulations of vaccines conferred protection against exposure to lethal doses of ricin, even after the lyophilized formulations had been stored at 40°C for 4 weeks. A corresponding liquid formulation of vaccine stored at 40°C elicited RTA-specific antibody titers but failed to confer immunity during a ricin challenge. PMID:23583494

Stabilization of a recombinant ricin toxin A subunit vaccine through lyophilization.

PubMed

Hassett, Kimberly J; Cousins, Megan C; Rabia, Lilia A; Chadwick, Chrystal M; O'Hara, Joanne M; Nandi, Pradyot; Brey, Robert N; Mantis, Nicholas J; Carpenter, John F; Randolph, Theodore W

2013-10-01

Lyophilization was used to prepare dry, glassy solid vaccine formulations of recombinant ricin toxin A-chain containing suspensions of colloidal aluminum hydroxide adjuvant. Four lyophilized formulations were prepared by using combinations of rapid or slow cooling during lyophilization and one of two buffers, histidine or ammonium acetate. Trehalose was used as the stabilizing excipient. Aggregation of the colloidal aluminum hydroxide suspension was reduced in formulations processed with a rapid cooling rate. Aluminum hydroxide particle size distributions, glass transition temperatures, water contents, and immunogenicities of lyophilized vaccines were independent of incubation time at 40 °C for up to 15 weeks. Mice immunized with reconstituted ricin toxin subunit A (RTA) vaccines produced RTA-specific antibodies and toxin-neutralizing antibodies (TNAs) regardless of the length of high temperature vaccine storage or the degree of aluminum adjuvant aggregation that occurred during lyophilization. In murine studies, lyophilized formulations of vaccines conferred protection against exposure to lethal doses of ricin, even after the lyophilized formulations had been stored at 40 °C for 4 weeks. A corresponding liquid formulation of vaccine stored at 40 °C elicited RTA-specific antibody titers but failed to confer immunity during a ricin challenge. Copyright © 2013 Elsevier B.V. All rights reserved.

Putty-like bone fillers based on CaP ceramics or Biosilicate® combined with carboxymethylcellulose: Characterization, optimization, and evaluation.

PubMed

Gabbai-Armelin, Paulo R; Renno, Ana Cm; Crovace, Murilo C; Magri, Angela Mp; Zanotto, Edgar D; Peitl, Oscar; Leeuwenburgh, Sander Cg; Jansen, John A; van den Beucken, Jeroen Jjp

2017-08-01

Calcium phosphates and bioactive glass ceramics have been considered promising biomaterials for use in surgeries. However, their moldability should be further enhanced. We here thereby report the handling, physicochemical features, and morphological characteristics of formulations consisting of carboxymethylcellulose-glycerol and hydroxyapatite-tricalcium phosphate or Biosilicate® particles. We hypothesized that combining either material with carboxymethylcellulose-glycerol would improve handling properties, retaining their bioactivity. In addition to scanning electron microscopy, cohesion, mineralization, pH, and viscoelastic properties of the novel formulations, cell culture experiments were performed to evaluate the cytotoxicity and cell proliferation. Putty-like formulations were obtained with improved cohesion and moldability. Remarkably, mineralization in simulated body fluid of hydroxyapatite-tricalcium phosphate/carboxymethylcellulose-glycerol formulations was enhanced compared to pure hydroxyapatite-tricalcium phosphate. Cell experiments showed that all formulations were noncytotoxic and that HA-TCP60 and BGC50 extracts led to an increased cell proliferation. We conclude that combining carboxymethylcellulose-glycerol with either hydroxyapatite-tricalcium phosphate or Biosilicate® allows for the generation of moldable putties, improves handling properties, and retains the ceramic bioactivity.

Incidence of hypertriglyceridemia in critically ill neonates receiving lipid injectable emulsions in glass versus plastic containers: a retrospective analysis.

PubMed

Martin, Camilia R; Dumas, Gregory J; Shoaie, Claire; Zheng, Zheng; Mackinnon, Brenda; Al-Aweel, Issa; Bistrian, Bruce R; Pursley, DeWayne M; Driscoll, David F

2008-02-01

To evaluate plasma clearance of lipid injectable emulsions packaged in either glass or plastic containers in neonates from 2 7-month periods, 1 year apart. Clinical records from June 1 to December 31, 2003 (glass [G] period) and the same months in 2004 (plastic [P] period) were assessed. Neonates who received lipid injectable emulsions were studied. Lipid container (glass vs plastic) was the independent variable. Of the 197 patients studied, 122 (G, 50/81; P, 72/116) had evaluable triglyceride (TG) levels, for an overall rate of 62%. Only birth weight (G, 1.09 +/- 0.32 kg vs P, 1.23 +/- .45 kg) and birth length (G, 36.4 +/- 3.5 cm vs P, 37.9 +/- 3.5 cm) were significantly different between the 2 groups (P = .047 and .028, respectively). There were no differences in the day of life on which lipid injection was started, the lipid dose, or the timing of TG measurements. The incidence of hypertriglyceridemia was significantly higher in the P period (G, 3/50 vs P, 19/72; P = .004). Administration of the same lipid formulation in plastic bags compared with glass containers is associated with higher rates of hypertriglyceridemia. The poorer clearance of lipids could be due to a higher proportion of large-diameter fat globules in plastic bags compared with those in glass containers.

A study of the interactions between glass-ionomer cement and S. sanguis biofilms

NASA Astrophysics Data System (ADS)

Hengtrakool, Chanotai

Glass-ionomer cements (GIC) have been used for dental procedures for many years and more recently in other medical applications such as bone cements, for bone reconstruction and also as drug release agents. The postulated caries-preventive activities of GIC are thought to result from their sealing ability, remineralization potential and antibacterial effects. Extensive 'in vitro' investigations have attempted to quantify these effects. In this study, an artificial mouth model, simulating 'in vivo' conditions at the tooth surface, was used to achieve a better understanding of the interaction of oral bacteria with the cements. This study investigated the interaction of Streptococcus sanguis, a common mouth commensal, with two glass-ionomer formulations (one containing fluoride and the other without fluoride ion) with particular reference to bacterial growth, changes in surface roughness and hardness of the glass-ionomer cement with respect to time. Restorative materials with rough surfaces will promote bacterial accumulation 'in vivo' and plaque formation is one factor in surface degradation. The constant depth film fermenter (CDFF) permits the examination of these phenomena and was used to investigate glass-ionomer/S. sanguis biofilm interaction over periods up to 14 days. In conjunction with these studies, surface roughness was measured using a 3-dimension laser profilometer and the surface hardness evaluated using a micro-indenter. Fluoride release from the cement was measured over 84 days. The results showed that autoclaving the CDFF prior to bacterial innoculate did not appear to affect the long-term fluoride release of the GIC. Laser profilometry revealed that the initial roughness and surface area of the GICs was significantly greater than the hydroxyapatite control. S. sanguis viable counts were significantly reduced for both glass-ionomer formulations in the shortterm, the greater reduction being with fluoride-GIC. S. sanguis biofilms produced similar hardness reduction on the surface of GIC:A to those observed with lactic acid pH 5 and artificial saliva whereas the effect on GIC:B was equivalent to that of lactic acid pH between 4 and 5. GICs showed changes in surface roughness after removal the biofilms. This indicates that while S. sanguis biofilm is affected by the GIC, there is also an increase in roughness of the cement indicating some degradation.

Polyfunctional epoxies. I - Rubber-toughened brominated and nonbrominated formulations for graphite composites. II - Nonrubber versus rubber-toughened brominated formulations for graphite composites

NASA Technical Reports Server (NTRS)

Nir, Z.; Gilwee, W. J.; Kourtides, D. A.; Parker, J. A.

1985-01-01

A new trifunctional epoxy resin, Tris-(hydroxyphenyl) methane triglycidyl ether, is compared to a state-of-the-art tetraglycidyl 4,4'-diaminodiphenyl methane (TGDDM), in graphite composites. Rubber-toughened brominated formulations of the epoxy resin are compared to nonbrominated ones in terms of their mechanical performance, environmental stability, thermochemical behavior, and flame retardancy. It is shown that the new resin performs almost the same way as the TGDDM does, but has improved glass transition temperature and environmental properties. Brominated polymeric additives (BPA) of different molecular weights are tested as a Br source to flame retardant graphite epoxy composites. The optimal molecular weight of the BPA and its polymeric backbone length are derived and compared with a 10 percent rubber-toughened formulation of the epoxy resin. Results indicate that when the Br content in the graphite composite is increased without the use of rubber, the mechanical properties improved. The use of BPAs as tougheners for graphite composites is also considered.

QUANTIFICATION OF GLYCYRRHIZIN BIOMARKER IN GLYCYRRHIZA GLABRA RHIZOME AND BABY HERBAL FORMULATIONS BY VALIDATED RP-HPTLC METHODS

PubMed Central

Alam, Prawez; Foudah, Ahmed I.; Zaatout, Hala H.; T, Kamal Y; Abdel-Kader, Maged S.

2017-01-01

Background: A simple and sensitive thin-layer chromatographic method has been established for quantification of glycyrrhizin in Glycyrrhiza glabra rhizome and baby herbal formulations by validated Reverse Phase HPTLC method. Materials and Methods: RP-HPTLC Method was carried out using glass coated with RP-18 silica gel 60 F254S HPTLC plates using methanol-water (7: 3 v/v) as mobile phase. Results: The developed plate was scanned and quantified densitometrically at 256 nm. Glycyrrhizin peaks from Glycyrrhiza glabra rhizome and baby herbal formulations were identified by comparing their single spot at Rf = 0.63 ± 0.01. Linear regression analysis revealed a good linear relationship between peak area and amount of glycyrrhizin in the range of 2000-7000 ng/band. Conclusion: The method was validated, in accordance with ICH guidelines for precision, accuracy, and robustness. The proposed method will be useful to enumerate the therapeutic dose of glycyrrhizin in herbal formulations as well as in bulk drug. PMID:28573236

Carbon-deuterium rotational-echo double-resonance NMR spectroscopy of lyophilized aspartame formulations.

PubMed

Luthra, Suman A; Utz, Marcel; Gorman, Eric M; Pikal, Michael J; Munson, Eric J; Lubach, Joseph W

2012-01-01

In this study, changes in the local conformation of aspartame were observed in annealed lyophilized glasses by monitoring changes in the distance between two labeled sites using C-(2)H rotational-echo double-resonance (REDOR) nuclear magnetic resonance (NMR) spectroscopy. Confirmation that the REDOR experiments were producing accurate distance measurement was ensured by measuring the (13)C-(15)N distance in glycine. The experiment was further verified by measuring the REDOR dephasing curve on (13)C-(2)H methionine. (13)C-(2)H REDOR dephasing curves were then measured on lyophilized aspartame-disaccharide formulations. In aspartame-sucrose formulation, the internuclear distances increased upon annealing, which correlated with decreased chemical reactivity. By contrast, annealing had only a minimal effect on the dephasing curve in aspartame-trehalose formulation. The results show that stability is a function of both mobility and local structure (conformation), even in a small molecule system such as lyophilized aspartame-sucrose. Copyright © 2011 Wiley-Liss, Inc.

DWPF DECON FRIT: SUMP AND SLURRY SOLIDS ANALYSIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crawford, C.; Peeler, D.; Click, D.

The Savannah River National Laboratory (SRNL) has been requested to perform analyses on samples of the Defense Waste Processing Facility (DWPF) decon frit slurry (i.e., supernate samples and sump solid samples). Four 1-L liquid slurry samples were provided to SRNL by Savannah River Remediation (SRR) from the 'front-end' decon activities. Additionally, two 1-L sump solids samples were provided to SRNL for compositional and physical analysis. In this report, the physical and chemical characterization results of the slurry solids and sump solids are reported. Crawford et al. (2010) provide the results of the supernate analysis. The results of the sump solidsmore » are reported on a mass basis given the samples were essentially dry upon receipt. The results of the slurry solids were converted to a volume basis given approximately 2.4 grams of slurry solids were obtained from the {approx}4 liters of liquid slurry sample. Although there were slight differences in the analytical results between the sump solids and slurry solids the following general summary statements can be made. Slight differences in the results are also captured for specific analysis. (1) Physical characterization - (a) SEM/EDS analysis suggested that the samples were enriched in Li and Si (B and Na not detectable using the current EDS system) which is consistent with two of the four principle oxides of Frit 418 (B{sub 2}O{sub 3}, Na{sub 2}O, Li{sub 2}O and SiO{sub 2}). (b) SEM/EDS analysis also identified impurities which were elementally consistent with stainless steel (i.e., Fe, Ni, Cr contamination). (c) XRD results indicated that the sump solids samples were amorphous which is consistent with XRD results expected for a Frit 418 based sample. (d) For the sump solids, SEM/EDS analysis indicated that the particle size of the sump solids were consistent with that of an as received Frit 418 sample from a current DWPF vendor. (e) For the slurry solids, SEM/EDS analysis indicated that the particle size range of the slurry solids was much broader than compared to the sump solids. More specifically, there were significantly more fines in the slurry solids as compared to the sump solids. (f) PSD results indicated that > 99% of both the sump and slurry solids were less than 350 microns. The PSD results also supported SEM/EDS analysis that there were significantly more fines in the slurry solids as compared to the sump solids. (2) Weight Percent Solids - Based on the measured supernate density and mass of insoluble solids (2.388 grams) filtered from the four liters of liquid slurry samples, the weight percent insoluble solids was estimated to be 0.060 wt%. This level of insoluble solids is higher than the ETP WAC limit of 100 mg/L, or 0.01 wt% which suggests a separation technology of some type would be required. (3) Chemical Analysis - (a) Elemental results from ICP-ES analysis indicated that the sump solids and slurry were very consistent with the nominal composition of Frit 418. There were other elements identified by ICP analysis which were either consistent with the presence of stainless steel (as identified by SEM/EDS analysis) or impurities that have been observed in 'as received' Frit 418 from the vendor. (b) IC anion analysis of the sump solids and slurry solids indicated all of the species were less than detection limits. (c) Radionuclide analysis of the sump solids also indicated that most of the analytes were either at or below the detection limits. (d) Organic analysis of the sump solids and slurry solids indicated all of the species were less than detection limits. It should be noted that the results of this study may not be representative of future decon frit solutions or sump/slurry solids samples. Therefore, future DWPF decisions regarding the possible disposal pathways for either the aqueous or solid portions of the Decon Frit system need to factor in the potential differences. More specifically, introduction of a different frit or changes to other DWPF flowsheet unit operations (e.g., different sludge batch or coupling with other process streams) may impact not only the results but also the conclusions regarding acceptability with respect to the ETF WAC limits or other alternative disposal options.« less

Freeze-dried snake antivenoms formulated with sorbitol, sucrose or mannitol: comparison of their stability in an accelerated test.

PubMed

Herrera, María; Tattini, Virgilio; Pitombo, Ronaldo N M; Gutiérrez, José María; Borgognoni, Camila; Vega-Baudrit, José; Solera, Federico; Cerdas, Maykel; Segura, Alvaro; Villalta, Mauren; Vargas, Mariángela; León, Guillermo

2014-11-01

Freeze-drying is used to improve the long term stability of pharmaceutical proteins. Sugars and polyols have been successfully used in the stabilization of proteins. However, their use in the development of freeze-dried antivenoms has not been documented. In this work, whole IgG snake antivenom, purified from equine plasma, was formulated with different concentrations of sorbitol, sucrose or mannitol. The glass transition temperatures of frozen formulations, determined by Differential Scanning Calorimetry (DSC), ranged between -13.5 °C and -41 °C. In order to evaluate the effectiveness of the different stabilizers, the freeze-dried samples were subjected to an accelerated stability test at 40 ± 2 °C and 75 ± 5% relative humidity. After six months of storage at 40 °C, all the formulations presented the same residual humidity, but significant differences were observed in turbidity, reconstitution time and electrophoretic pattern. Moreover, all formulations, except antivenoms freeze-dried with mannitol, exhibited the same potency for the neutralization of lethal effect of Bothrops asper venom. The 5% (w:v) sucrose formulation exhibited the best stability among the samples tested, while mannitol and sorbitol formulations turned brown. These results suggest that sucrose is a better stabilizer than mannitol and sorbitol in the formulation of freeze-dried antivenoms under the studied conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Quantifying the mode II critical strain energy release rate of borate bioactive glass coatings on Ti6Al4V substrates.

PubMed

Matinmanesh, A; Li, Y; Clarkin, O; Zalzal, P; Schemitsch, E H; Towler, M R; Papini, M

2017-11-01

Bioactive glasses have been used as coatings for biomedical implants because they can be formulated to promote osseointegration, antibacterial behavior, bone formation, and tissue healing through the incorporation and subsequent release of certain ions. However, shear loading on coated implants has been reported to cause the delamination and loosening of such coatings. This work uses a recently developed fracture mechanics testing methodology to quantify the critical strain energy release rate under nearly pure mode II conditions, G IIC , of a series of borate-based glass coating/Ti6Al4V alloy substrate systems. Incorporating increasing amounts of SrCO 3 in the glass composition was found to increase the G IIC almost twofold, from 25.3 to 46.9J/m 2 . The magnitude and distribution of residual stresses in the coating were quantified, and it was found that the residual stresses in all cases distributed uniformly over the cross section of the coating. The crack was driven towards, but not into, the glass/Ti6Al4V substrate interface due to the shear loading. This implied that the interface had a higher fracture toughness than the coating itself. Copyright © 2017 Elsevier Ltd. All rights reserved.

Composition formulas of Fe-based transition metals-metalloid bulk metallic glasses derived from dual-cluster model of binary eutectics.

PubMed

Naz, Gul Jabeen; Dong, Dandan; Geng, Yaoxiang; Wang, Yingmin; Dong, Chuang

2017-08-22

It is known that bulk metallic glasses follow simple composition formulas [cluster](glue atom) 1 or 3 with 24 valence electrons within the framework of the cluster-plus-glue-atom model. Though the relevant nearest-neighbor cluster can be readily identified from a devitrification phase, the glue atoms remains poorly defined. The present work is devoted to understanding the composition rule of Fe-(B,P,C) based multi-component bulk metallic glasses, by introducing a cluster-based eutectic liquid model. This model regards a eutectic liquid to be composed of two stable liquids formulated respectively by cluster formulas for ideal metallic glasses from the two eutectic phases. The dual cluster formulas are first established for binary Fe-(B,C,P) eutectics: [Fe-Fe 14 ]B 2 Fe + [B-B 2 Fe 8 ]Fe ≈ Fe 83.3 B 16.7 for eutectic Fe 83 B 17 , [P-Fe 14 ]P + [P-Fe 9 ]P 2 Fe≈Fe 82.8 P 17.2 for Fe 83 P 17 , and [C-Fe 6 ]Fe 3  + [C-Fe 9 ]C 2 Fe ≈ Fe 82.6 C 17.4 for Fe 82.7 C 17.3 . The second formulas in these dual-cluster formulas, being respectively relevant to devitrification phases Fe 2 B, Fe 3 P, and Fe 3 C, well explain the compositions of existing Fe-based transition metals-metalloid bulk metallic glasses. These formulas also satisfy the 24-electron rule. The proposition of the composition formulas for good glass formers, directly from known eutectic points, constitutes a new route towards understanding and eventual designing metallic glasses of high glass forming abilities.

Glass Composition Constraint Recommendations for Use in Life-Cycle Mission Modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCloy, John S.; Vienna, John D.

2010-05-03

The component concentration limits that most influence the predicted Hanford life-cycle HLW glass volume by HTWOS were re-evaluated. It was assumed that additional research and development work in glass formulation and melter testing would be performed to improve the understanding of component effects on the processability and product quality of these HLW glasses. Recommendations were made to better estimate the potential component concentration limits that could be applied today while technology development is underway to best estimate the volume of HLW glass that will eventually be produced at Hanford. The limits for concentrations of P2O5, Bi2O3, and SO3 were evaluatedmore » along with the constraint used to avoid nepheline formation in glass. Recommended concentration limits were made based on the current HLW glass property models being used by HTWOS (Vienna et al. 2009). These revised limits are: 1) The current ND should be augmented by the OB limit of OB ≤ 0.575 so that either the normalized silica (NSi) is less that the 62% limit or the OB is below the 0.575 limit. 2) The mass fraction of P2O5 limit should be revised to allow for up to 4.5 wt%, depending on CaO concentrations. 3) A Bi2O3 concentration limit of 7 wt% should be used. 4) The salt accumulation limit of 0.5 wt% SO3 may be increased to 0.6 wt%. Again, these revised limits do not obviate the need for further testing, but make it possible to more accurately predict the impact of that testing on ultimate HLW glass volumes.« less

Physicochemical characterization and drug-release properties of celecoxib hot-melt extruded glass solutions.

PubMed

Andrews, Gavin P; Abu-Diak, Osama; Kusmanto, Febe; Hornsby, Peter; Hui, Zhai; Jones, David S

2010-11-01

The interest in hot-melt extrusion (HME) as a drug delivery technology for the production of glass solutions is growing rapidly. HME glass solutions have a tendency to recrystallize during storage and also typically have a very dense structure, restricting the ingress of dissolution fluid and retarding drug release. In this study, we have used HME to manufacture glass solutions containing celecoxib (CX) and polyvinylpyrrolidone (PVP) and have assessed the use of supercritical carbon dioxide (scCO2) as a pore-forming agent to enhance drug release. Differential scanning calorimetry confirmed the formation of glass solutions following extrusion. All extrudates exhibited a single glass transition temperature (Tg), positioned between the Tg values of CX and PVP. The instability of glass solutions is a significant problem during storage. Stabilization may be improved through the appropriate choice of excipient to facilitate drug–polymer interactions. The Gordon–Taylor equation showed that the Tg values of all extrudates expected on ideal mixing were lower than those observed experimentally. This may be indicative of drug–polymer interactions that decrease free volume and elevate the Tg. Molecular interactions between CX and PVP were further confirmed using Fourier transform infrared and Raman spectroscopy. Storage stability of the extrudates was shown to be dependent on drug loading. Samples containing a higher CX loading were less stable, which we ascribed to decreased Tg and hence increased mobility within the drug–polymer matrix. The solubility of CX was improved through the formulation of extruded glass solutions, but release rate was relatively slow. Exposure of extrudates to scCO2 had no effect on the solid-state properties of CX but did produce a highly porous structure. The drug-release rate from extrudates after scCO2 exposure was significantly higher.

The effect of colouring agent on the physical properties of glass ceramic produced from waste glass for antimicrobial coating deposition

NASA Astrophysics Data System (ADS)

Juoi, J. M.; Ayoob, N. F.; Rosli, Z. M.; Rosli, N. R.; Husain, K.

2016-07-01

Domestic waste glass is utilized as raw material for the production of glass ceramic material (GCM) via sinter crystallisation route. The glass ceramic material in a form of tiles is to be utilized for the deposition of Ag-TiO2 antimicrobial coating. Two types of soda lime glass (SLG) that are non-coloured and green SLG are utilised as main raw materials during the batch formulation in order to study the effect of colouring agent (Fe2O3) on the physical and mechanical properties of glass ceramic produced. Glass powder were prepared by crushing bottles using hammer milled with milling machine and sieved until they passed through 75 µm sieve. The process continues by mixing glass powder with ball clay with ratio of 95:5 wt. %, 90:10 wt. % and 85:15 wt. %. Each batch mixture was then uniaxial pressed and sintered at 800°C, 825 °C and 850 °C. The physical and mechanical properties were then determined and compared between those produced from non-coloured and green coloured SLG in order to evaluate the effect of colouring agent (Fe2O3) on the GCM produced. The optimum properties of non-coloured SLG is produced with smaller ball clay content (10 wt. %) compared to green SLG (15 wt. %). The physical properties (determined thru ASTM C373) of the optimized GCM produced from non-coloured SLG and green SLG are 0.69 % of porosity, 1.92 g/cm3 of bulk density, 0.36 % of water absorption; and 1.96 % of porosity, 2.69 g/cm3 of bulk density, 0.73 % of water absorption; respectively. Results also indicate that the most suitable temperature in producing GCM from both glasses with optimized physical and mechanical properties is at 850 °C.

Implementation of flowsheet change to minimize hydrogen and ammonia generation during chemical processing of high level waste in the Defense Waste Processing Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, Dan P.; Woodham, Wesley H.; Williams, Matthew S.

Testing was completed to develop a chemical processing flowsheet for the Defense Waste Processing Facility (DWPF), designed to vitrify and stabilize high level radioactive waste. DWPF processing uses a reducing acid (formic acid) and an oxidizing acid (nitric acid) to rheologically thin the slurry and complete the necessary acid base and reduction reactions (primarily mercury and manganese). Formic acid reduces mercuric oxide to elemental mercury, allowing the mercury to be removed during the boiling phase of processing through steam stripping. In runs with active catalysts, formic acid can decompose to hydrogen and nitrate can be reduced to ammonia, both flammablemore » gases, due to rhodium and ruthenium catalysis. Replacement of formic acid with glycolic acid eliminates the generation of rhodium- and ruthenium-catalyzed hydrogen and ammonia. In addition, mercury reduction is still effective with glycolic acid. Hydrogen, ammonia and mercury are discussed in the body of the report. Ten abbreviated tests were completed to develop the operating window for implementation of the flowsheet and determine the impact of changes in acid stoichiometry and the blend of nitric and glycolic acid as it impacts various processing variables over a wide processing region. Three full-length 4-L lab-scale simulations demonstrated the viability of the flowsheet under planned operating conditions. The flowsheet is planned for implementation in early 2017.« less

Sludge batch 9 (SB9) acceptance evaluation. Radionuclide concentrations in tank 51 SB9 qualification sample prepared at SRNL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C. J.; Diprete, D. P.; Pareizs, J. M.

Presented in this report are radionuclide concentrations required as part of the program of qualifying Sludge Batch 9 (SB9) for processing in the Defense Waste Processing Facility (DWPF). The SB9 material is currently in Tank 51 and has been washed and prepared for transfer to Tank 40. The acceptance evaluation needs to be completed prior to the transfer of the material in Tank 51 to Tank 40. The sludge slurry in Tank 40 has already been qualified for DWPF processing and is currently being processed as Sludge Batch 8 (SB8). The radionuclide concentrations were measured or estimated in the Tankmore » 51 SB9 Washed Qualification Sample prepared at Savannah River National Laboratory (SRNL). This sample was prepared from a three liter sample of Tank 51 sludge slurry (HTF-51-15-81) taken on July 23, 2015. The sample was delivered to SRNL where it was initially characterized in the Shielded Cells. Under the direction of Savannah River Remediation (SRR) it was then adjusted per the Tank Farm washing strategy as of October 20, 2015. This final slurry now has a composition expected to be similar to that of the slurry in Tank 51 after final preparations have been made for transfer of that slurry to Tank 40.« less

Sludge batch 9 (SB9) accepance evaluation: Radionuclide concentrations in tank 51 SB9 qualification sample prepared at SRNL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C.; Diprete, D.; Pareizs, J.

Presented in this report are radionuclide concentrations required as part of the program of qualifying Sludge Batch 9 (SB9) for processing in the Defense Waste Processing Facility (DWPF). The SB9 material is currently in Tank 51 and has been washed and prepared for transfer to Tank 40. The acceptance evaluation needs to be completed prior to the transfer of the material in Tank 51 to Tank 40. The sludge slurry in Tank 40 has already been qualified for DWPF processing and is currently being processed as Sludge Batch 8 (SB8). The radionuclide concentrations were measured or estimated in the Tankmore » 51 SB9 Washed Qualification Sample prepared at Savannah River National Laboratory (SRNL). This sample was prepared from a three liter sample of Tank 51 sludge slurry (HTF-51-15-81) taken on July 23, 2015. The sample was delivered to SRNL where it was initially characterized in the Shielded Cells. Under the direction of Savannah River Remediation (SRR) it was then adjusted per the Tank Farm washing strategy as of October 20, 2015. This final slurry now has a compositioniv expected to be similar to that of the slurry in Tank 51 after final preparations have been made for transfer of that slurry to Tank 40.« less

Development of the rectal dosage form with silver-coated glass beads for local-action applications in lower sections of the gastrointestinal tract.

PubMed

Siczek, Krzysztof; Fichna, Jakub; Zatorski, Hubert; Karolewicz, Bożena; Klimek, Leszek; Owczarek, Artur

2018-03-01

Recent findings indicating the anti-inflammatory action of silver preparations through modulation of the gut microbiota and apoptosis of inflammatory cells predestine silver use in inflammatory bowel disease (IBD). The aim of our study was to validate the possibility of effective silver release from silver-coated glass beads for anti-inflammatory local application in the lower sections of the gastrointestinal (GI) tract. Silver-coated glass beads were prepared using magnetron method. Release of silver from the silver-coated glass bead surface was carried out in BIO-DIS reciprocating cylinder apparatus. Erosion of silver coating and indirect estimation of the silver release dynamics was assessed using scanning electron microscope. Rectal suppositories containing silver-coated glass beads were prepared using five different methods (M1-M5) and X-ray scanned for their composition. The XR microanalysis and the chemical composition analysis evidenced for a rapid (within 30 min) release of nearly 50% of silver from the coating of the glass beads, which remained stable up to 24 h of incubation. The most homogeneous distribution of beads in the entire volume of the suppository was obtained for formulation M5, where the molten base was poured into mold placed in an ice bath, and the beads were added after 10 s. Our study is the first to present the concept of enclosing silver-coated glass beads in the lipophilic suppository base to attenuate inflammation in the lower GI tract and promises efficient treatment with reduced side effects.

Stable sugar-based protein formulations by supercritical fluid drying.

PubMed

Jovanović, Natasa; Bouchard, Andréanne; Sutter, Marc; Van Speybroeck, Michiel; Hofland, Gerard W; Witkamp, Geert-Jan; Crommelin, Daan J A; Jiskoot, Wim

2008-01-04

The aim of this work was to produce stable, sugar-containing protein formulations by supercritical fluid (SCF) drying. Lysozyme solutions with and without added sucrose or trehalose were dried by spraying them in an SCF composed of CO(2) and ethanol or CO(2) only. The protein-to-sugar ratio was varied between 1:0 and 1:10 (w/w). Dried formulations were stored at 4 degrees C for three months and analyzed by Karl Fischer titration, scanning electron microscopy, X-ray powder diffraction, differential scanning calorimetry and Fourier transform infrared spectroscopy. Lysozyme stability after reconstitution was determined by an enzymatic activity assay, UV/Vis spectroscopy, and SDS-PAGE. Smooth, spherical particles of 1-25 microm size were obtained. All formulations were initially amorphous. Crystallization during storage only occurred with a protein-to-sugar ratio of 1:10 and could be avoided by performing SCF drying without ethanol. Absence of residual ethanol in dried trehalose formulations increased the glass transition temperature up to 120 degrees C. Lysozyme in dried formulations was structurally stable, with exception of the 1:0 and 1:1 protein-to-sugar ratios, where reversible protein aggregation occurred. The results show that by avoiding ethanol, which up to now has been considered mandatory for efficient drying of aqueous solutions, and by choosing the proper protein-to-sugar ratio, it is possible to obtain stable, sugar-based protein formulations through SCF drying.

Biorelevant Dissolution Models for a Weak Base To Facilitate Formulation Development and Overcome Reduced Bioavailability Caused by Hypochlordyria or Achlorhydria.

PubMed

Kou, Dawen; Dwaraknath, Sudharsan; Fischer, Yannick; Nguyen, Daniel; Kim, Myeonghui; Yiu, Hiuwing; Patel, Preeti; Ng, Tania; Mao, Chen; Durk, Matthew; Chinn, Leslie; Winter, Helen; Wigman, Larry; Yehl, Peter

2017-10-02

In this study, two dissolution models were developed to achieve in vitro-in vivo relationship for immediate release formulations of Compound-A, a poorly soluble weak base with pH-dependent solubility and low bioavailability in hypochlorhydric and achlorhydric patients. The dissolution models were designed to approximate the hypo-/achlorhydric and normal fasted stomach conditions after a glass of water was ingested with the drug. The dissolution data from the two models were predictive of the relative in vivo bioavailability of various formulations under the same gastric condition, hypo-/achlorhydric or normal. Furthermore, the dissolution data were able to estimate the relative performance under hypo-/achlorhydric and normal fasted conditions for the same formulation. Together, these biorelevant dissolution models facilitated formulation development for Compound-A by identifying the right type and amount of key excipient to enhance bioavailability and mitigate the negative effect of hypo-/achlorhydria due to drug-drug interaction with acid-reducing agents. The dissolution models use readily available USP apparatus 2, and their broader utility can be evaluated on other BCS 2B compounds with reduced bioavailability caused by hypo-/achlorhydria.

Near-infrared analysis of hydrogen-bonding in glass- and rubber-state amorphous saccharide solids.

PubMed

Izutsu, Ken-ichi; Hiyama, Yukio; Yomota, Chikako; Kawanishi, Toru

2009-01-01

Near-infrared (NIR) spectroscopic analysis of noncrystalline polyols and saccharides (e.g., glycerol, sorbitol, maltitol, glucose, sucrose, maltose) was performed at different temperatures (30-80 degrees C) to elucidate the effect of glass transition on molecular interaction. Transmission NIR spectra (4,000-12,000 cm(-1)) of the liquids and cooled-melt amorphous solids showed broad absorption bands that indicate random configuration of molecules. Heating of the samples decreased an intermolecular hydrogen-bonding OH vibration band intensity (6,200-6,500 cm(-1)) with a concomitant increase in a free and intramolecular hydrogen-bonding OH group band (6,600-7,100 cm(-1)). Large reduction of the intermolecular hydrogen-bonding band intensity at temperatures above the glass transition (T(g)) of the individual solids should explain the higher molecular mobility and lower viscosity in the rubber state. Mixing of the polyols with a high T(g) saccharide (maltose) or an inorganic salt (sodium tetraborate) shifted both the glass transition and the inflection point of the hydrogen-bonding band intensity to higher temperatures. The implications of these results for pharmaceutical formulation design and process monitoring (PAT) are discussed.

Water Absorption and Thickness Swelling Behavior of Polypropylene Reinforced with Hybrid Recycled Newspaper and Glass Fiber

NASA Astrophysics Data System (ADS)

Shakeri, Alireza; Ghasemian, Ali

2010-04-01

This study aims to investigate the moisture absorption of recycled newspaper fiber and recycled newspaper-glass fiber hybrid reinforced polypropylene composites to study their suitability in outdoor applications. In this work composite materials were made from E-glass fiber (G), recycled newspaper (NP) and polypropylene (PP), by using internal mixing and hot-pressing molding. Long-term water absorption (WA) and thickness swelling (TS) kinetics of the composites was investigated with water immersion. It was found that the WA and TS increase with NP content in composite and water immersion time before an equilibrium condition was reached. Composites made from the NP show comparable results as those made of the hybrid fiber. The results suggest that the water absorption and thickness swelling composite decrease with increasing glass fiber contents in hybrid fiber composite. It is interesting to find that the WA and TS can be reduced significantly with incorporation of a coupling agent (maleated polypropylene) in the composite formulation. Further studies were conducted to model the water diffusion and thickness swelling of the composites. Diffusion coefficients and swelling rate parameters in the models were obtained by fitting the model predictions with the experimental data.

Extremal Optimization for Quadratic Unconstrained Binary Problems

NASA Astrophysics Data System (ADS)

Boettcher, S.

We present an implementation of τ-EO for quadratic unconstrained binary optimization (QUBO) problems. To this end, we transform modify QUBO from its conventional Boolean presentation into a spin glass with a random external field on each site. These fields tend to be rather large compared to the typical coupling, presenting EO with a challenging two-scale problem, exploring smaller differences in couplings effectively while sufficiently aligning with those strong external fields. However, we also find a simple solution to that problem that indicates that those external fields apparently tilt the energy landscape to a such a degree such that global minima become more easy to find than those of spin glasses without (or very small) fields. We explore the impact of the weight distribution of the QUBO formulation in the operations research literature and analyze their meaning in a spin-glass language. This is significant because QUBO problems are considered among the main contenders for NP-hard problems that could be solved efficiently on a quantum computer such as D-Wave.

Effect of sodium chloride on the glass transition of condensed starch systems.

PubMed

Chuang, Lillian; Panyoyai, Naksit; Shanks, Robert; Kasapis, Stefan

2015-10-01

The present investigation deals with the structural properties of condensed potato starch-sodium chloride systems undergoing a thermally induced glass transition. Sample preparation included hot pressing at 120°C for 7 min to produce extensive starch gelatinisation. Materials covered a range of moisture contents from 3.6% to 18.8%, which corresponded to relative humidity values of 11% and 75%. Salt addition was up to 6.0% in formulations. Instrumental work was carried out with dynamic mechanical analysis in tension, modulated differential scanning calorimetry, Fourier transform infrared spectroscopy, scanning electron microscopy and wide angle X-ray diffraction. Experimental conditions ensured the development of amorphous matrices that exhibited thermally reversible glassy consistency. Both moisture content and addition of sodium chloride affected the mechanical strength and glass transition temperature of polymeric systems. Sodium ions interact with chemical moieties of the polysaccharide chain to alter considerably structural properties, as compared to the starch-water matrix. Copyright © 2015. Published by Elsevier Ltd.

Polyglycerol coatings of glass vials for protein resistance.

PubMed

Höger, Kerstin; Becherer, Tobias; Qiang, Wei; Haag, Rainer; Friess, Wolfgang; Küchler, Sarah

2013-11-01

Proteins are surface active molecules which undergo non-specific adsorption when getting in contact with surfaces such as the primary packaging material. This process is critical as it may cause a loss of protein content or protein aggregation. To prevent unspecific adsorption, protein repellent coatings are of high interest. We describe the coating of industrial relevant borosilicate glass vials with linear methoxylated polyglycerol, hyperbranched polyglycerol, and hyperbranched methoxylated polyglycerol. All coatings provide excellent protein repellent effects. The hyperbranched, non-methoxylated coating performed best. The protein repellent properties were maintained also after applying industrial relevant sterilization methods (≥200 °C). Marginal differences in antibody stability between formulations stored in bare glass vials and coated vials were detected after 3 months storage; the protein repellent effect remained largely stable. Here, we describe a new material suitable for the coating of primary packaging material of proteins which significantly reduces the protein adsorption and thus could present an interesting new possibility for biomedical applications. Copyright © 2013 Elsevier B.V. All rights reserved.

Risk assessment of amorphous silicon dioxide nanoparticles in a glass cleaner formulation

PubMed Central

Scheel, Julia; Karsten, Stefan; Stelter, Norbert; Wind, Thorsten

2013-01-01

Since nanomaterials are a heterogeneous group of substances used in various applications, risk assessment needs to be done on a case-by-case basis. Here the authors assess the risk (hazard and exposure) of a glass cleaner with synthetic amorphous silicon dioxide (SAS) nanoparticles during production and consumer use (spray application). As the colloidal material used is similar to previously investigated SAS, the hazard profile was considered to be comparable. Overall, SAS has a low toxicity. Worker exposure was analysed to be well controlled. The particle size distribution indicated that the aerosol droplets were in a size range not expected to reach the alveoli. Predictive modelling was used to approximate external exposure concentrations. Consumer and environmental exposure were estimated conservatively and were not of concern. It was concluded based on the available weight-of-evidence that the production and application of the glass cleaner is safe for humans and the environment under intended use conditions. PMID:22548260

Sensitivity of novel silicate and borate-based glass structures on in vitro bioactivity and degradation behaviour.

PubMed

Mancuso, Elena; Bretcanu, Oana; Marshall, Martyn; Dalgarno, Kenneth W

2017-10-15

Three novel glass compositions, identified as NCL2 (SiO 2 -based), NCL4 (B 2 O 3 -based) and NCL7 (SiO 2 -based), along with apatite-wollastonite (AW) were processed to form sintered dense pellets, and subsequently evaluated for their in vitro bioactive potential, resulting physico-chemical properties and degradation rate. Microstructural analysis showed the carbonated hydroxyapatite (HCA) precipitate morphology following SBF testing to be composition-dependent. AW and the NCL7 formulation exhibited greater HCA precursor formation than the NCL2 and NCL4-derived pellets. Moreover, the NCL4 borate-based samples showed the highest biodegradation rate; with silicate-derived structures displaying the lowest weight loss after SBF immersion. The results of this study suggested that glass composition has significant influence on apatite-forming ability and also degradation rate, indicating the possibility to customise the properties of this class of materials towards the bone repair and regeneration process.

Rubber-toughened polyfunctional epoxies - Brominated vs nonbrominated formulated for graphite composites

NASA Technical Reports Server (NTRS)

Nir, Z.; Gilwee, W. J.; Kourtides, D. A.; Parker, J. A.

1983-01-01

A new, commercially available, trifunctional epoxy resin (tris-(hydroxyphenyl)-methane triglycidyl ether) was modified with synthetic rubber to increase the impact resistance of epoxy/graphite composites. These composites were reinforced with commercially available satin-weave carbon cloth using two formulations of epoxies (brominated and nonbrominated) containing various amounts of carboxy-terminated butadience acrylonitrile (CTBN) rubber that had been prereacted with epoxy resin. The impact resistance was determined by measuring the interlaminar shear strength of the composites after impact. The mechanical properties, such as flexural strength and modulus at room temperature and at 93 C, were also determined. Measurements were taken of the flammability and glass transition temperature (Tg); and a thermal-gravimetric analysis was made.

Mercury Phase II Study - Mercury Behavior across the High-Level Waste Evaporator System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C. J.; Crawford, C. L.; Jackson, D. G.

2016-06-17

The Mercury Program team’s effort continues to develop more fundamental information concerning mercury behavior across the liquid waste facilities and unit operations. Previously, the team examined the mercury chemistry across salt processing, including the Actinide Removal Process/Modular Caustic Side Solvent Extraction Unit (ARP/MCU), and the Defense Waste Processing Facility (DWPF) flowsheets. This report documents the data and understanding of mercury across the high level waste 2H and 3H evaporator systems.

Medical imaging scintillators from glass-ceramics using mixed rare-earth halides

NASA Astrophysics Data System (ADS)

Beckert, M. Brooke; Gallego, Sabrina; Ding, Yong; Elder, Eric; Nadler, Jason H.

2016-10-01

Recent years have seen greater interest in developing new luminescent materials to replace scintillator panels currently used in medical X-ray imaging systems. The primary areas targeted for improvement are cost and image resolution. Cost reduction is somewhat straightforward in that less expensive raw materials and processing methods will yield a less expensive product. The path to improving image resolution is more complex because it depends on several properties of the scintillator material including density, transparency, and composition, among others. The present study focused on improving image resolution using composite materials, known as glass-ceramics that contain nanoscale scintillating crystallites formed within a transparent host glass matrix. The small size of the particles and in-situ precipitation from the host glass are key to maintaining transparency of the composite scintillator, which ensures that a majority of the light produced from absorbed X-rays can actually be used to create an image of the patient. Because light output is the dominating property that determines the image resolution achievable with a given scintillator, it was used as the primary metric to evaluate performance of the glass-ceramics relative to current scintillators. Several glass compositions were formulated and then heat treated in a step known as "ceramization" to grow the scintillating nanocrystals, whose light output was measured in response to a 65 kV X-ray source. Performance was found to depend heavily on the thermal history of the glass and glass-ceramic, and so additional studies are required to more precisely determine optimal process temperatures. Of the compositions investigated, an alumino-borosilicate host glass containing 56mol% scintillating rare-earth halides (BaF2, GdF3, GdBr3, TbF3) produced the highest recorded light output at nearly 80% of the value recorded using a commercially-available GOS:Tb panel as a reference.

Effects of Al2O3, B2O3, Li2O, Na2O, and SiO2 on Nepheline Crystallization in Hanford High Level Waste Glasses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kroll, Jared O.; Vienna, John D.; Schweiger, Michael J.

2016-09-15

Nepheline (nominally NaAlSiO4) formation during slow cooling of high-alumina (25.4 - 34.5 mass% Al2O3) Hanford high level waste glasses may significantly reduce product durability. To investigate the effects of composition on nepheline crystallization, 29 compositions were formulated by adjusting Al2O3, B2O3, Li2O, Na2O, and SiO2 around a baseline glass that precipitated 12 mass% nepheline. Thirteen of these compositions were generated by adjusting one-component-at-a-time, while two or three components were adjusted to produce the other 16 (with all remaining components staying in the same relative proportions). Quantitative X-ray diffraction was used to determine nepheline concentration in each sample. Twenty two glassesmore » precipitated nepheline, two of which also precipitated eucryptite (nominally LiAlSiO4), and one glass formed only eucryptite upon slow cooling. Increasing Na2O and Li2O had the strongest effect in promoting nepheline formation. Increasing B2O3 inhibited nepheline formation. SiO2 and Al2O3 showed non-linear behavior related to nepheline formation. The composition effects on nepheline formation in these glasses are reported.« less

Effect of ambient light on monoclonal antibody product quality during small-scale mammalian cell culture process in clear glass bioreactors.

PubMed

Mallaney, Mary; Wang, Szu-Han; Sreedhara, Alavattam

2014-01-01

During a small-scale cell culture process producing a monoclonal antibody, a larger than expected difference was observed in the charge variants profile of the harvested cell culture fluid (HCCF) between the 2 L and larger scales (e.g., 400 L and 12 kL). Small-scale studies performed at the 2 L scale consistently showed an increase in acidic species when compared with the material made at larger scale. Since the 2 L bioreactors were made of clear transparent glass while the larger scale reactors are made of stainless steel, the effect of ambient laboratory light on cell culture process in 2 L bioreactors as well as handling the HCCF was carefully evaluated. Photoreactions in the 2 L glass bioreactors including light mediated increase in acidic variants in HCCF and formulation buffers were identified and carefully analyzed. While the acidic variants comprised of a mixture of sialylated, reduced disulfide, crosslinked (nonreducible), glycated, and deamidated forms, an increase in the nonreducible forms, deamidation and Met oxidation was predominantly observed under light stress. The monoclonal antibody produced in glass bioreactors that were protected from light behaved similar to the one produced in the larger scale. Our data clearly indicate that care should be taken when glass bioreactors are used in cell culture studies during monoclonal antibody production. © 2014 American Institute of Chemical Engineers.

Strontium-based glass polyalkenoate cements for luting applications in the skeleton.

PubMed

Clarkin, O; Boyd, D; Towler, M R

2010-02-01

Glass Polyalkenoate Cements (GPCs) based on strontium calcium zinc silicate (Sr-Ca-Zn-SiO2) glasses and high molecular weight poly(acrylic acid) (PAA) have been shown to exhibit suitable mechanical properties for orthopaedic arthroplasty applications, however for vertebroplasty and other medical luting applications these cements have working and setting times which are unsuitable for such applications. In this study GPCs based on Sr-Ca-Zn-SiO2 glasses and low molecular weight PAA were evaluated for orthopaedic luting applications. GPCs based on four different glasses; BT100 (0.16CaO, 0.36ZnO, 0.48SiO2), BT101 (0.04SrO, 0.12CaO, 0.36ZnO, 0.48SiO2), BT102 (0.08SrO 0.08CaO, 0.36ZnO, 0.48SiO2) and BT103 (0.12SrO 0.04CaO, 0.36ZnO, 0.48SiO2) and two PAAs (MW; 12,700 and 25,700) were examined. These cement formulations exhibited handling properties potentially suitable for luting applications as well as mechanical strengths which were similar to those of trabecular bone. Upon immersion in simulated body fluid, the GPCs showed sustained growth of a calcium phosphate layer on the surface of the cement indicating that these cements were bioactive in nature.

Final Report - LAW Envelope C Glass Formulation Testing to Increase Waste Loading, VSL-05R5900-1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, Albert A.; Pegg, I. L.; Matlack, K. S.

2013-12-03

This report describes the results of testing specified by Test Plan VSL-05R5900-1 Rev.0. The work was performed in compliance with the quality assurance requirements specified in the Test Plan. Results required by the Test Plan are reported. The test results and this report have been reviewed for correctness, technical adequacy, completeness, and accuracy.

Prediction of the Formulation Dependence of the Glass Transition Temperature for Amine-Epoxy Copolymers Using a Quantitative Structure-Property Relationship Based on the AM1 Method

DTIC Science & Technology

2004-02-01

Products and Chemicals , Inc . The stoichiometry of the DGEBA-PACM polymerization reaction was varied to yield epoxy/amine ratios ranging from ~2:1 through...equivalent). The DGEBA epoxy resin was cured with bis(p-aminocyclohexyl)methane (PACM) (EEW = 52.5 g/equivalent), which was acquired from Air

Modification of conventional glass-ionomer cements with N-vinylpyrrolidone containing polyacids, nano-hydroxy and fluoroapatite to improve mechanical properties.

PubMed

Moshaverinia, Alireza; Ansari, Sahar; Movasaghi, Zanyar; Billington, Richard W; Darr, Jawwad A; Rehman, Ihtesham U

2008-10-01

The objective of this study was to enhance the mechanical strength of glass-ionomer cements, while preserving their unique clinical properties. Copolymers incorporating several different segments including N-vinylpyrrolidone (NVP) in different molar ratios were synthesized. The synthesized polymers were copolymers of acrylic acid and NVP with side chains containing itaconic acid. In addition, nano-hydroxyapatite and fluoroapatite were synthesized using an ethanol-based sol-gel technique. The synthesized polymers were used in glass-ionomer cement formulations (Fuji II commercial GIC) and the synthesized nanoceramic particles (nano-hydroxy or fluoroapatite) were also incorporated into commercial glass-ionomer powder, respectively. The synthesized materials were characterized using FTIR and Raman spectroscopy and scanning electron microscopy. Compressive, diametral tensile and biaxial flexural strengths of the modified glass-ionomer cements were evaluated. After 24h setting, the NVP modified glass-ionomer cements exhibited higher compressive strength (163-167 MPa), higher diametral tensile strength (DTS) (13-17 MPa) and much higher biaxial flexural strength (23-26 MPa) in comparison to Fuji II GIC (160 MPa in CS, 12MPa in DTS and 15 MPa in biaxial flexural strength). The nano-hydroxyapatite/fluoroapatite added cements also exhibited higher CS (177-179 MPa), higher DTS (19-20 MPa) and much higher biaxial flexural strength (28-30 MPa) as compared to the control group. The highest values for CS, DTS and BFS were found for NVP-nanoceramic powder modified cements (184 MPa for CS, 22 MPa for DTS and 33 MPa for BFS) which were statistically higher than control group. It was concluded that, both NVP modified and nano-HA/FA added glass-ionomer cements are promising restorative dental materials with improved mechanical properties.

Adhesion Strength Study of EVA Encapsulants on Glass Substrates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pern, F. J.; Glick, S. H.

2003-05-01

An extensive peel-test study was conducted to investigate the various factors that may affect the adhesion strength of photovoltaic module encapsulants, primarily ethylene-vinyl acetate (EVA), on glass substrates of various laminates based on a common configuration of glass/encapsulant/backfoil. The results show that"pure" or"absolute" adhesion strength of EVA-to-glass was very difficult to obtain because of tensile deformation of the soft, semi-elastic EVA layer upon pulling. A mechanically"strong enough" backing foil on the EVA was critical to achieving the"apparent" adhesion strength. Peel test method with a 90-degree-pull yielded similar results to a 180-degree-pull. The 90-degree-pull method better revealed the four stages ofmore » delamination failure of the EVA/backfoil layers. The adhesion strength is affected by a number of factors, which include EVA type, formulation, backfoil type and manufacturing source, glass type, and surface priming treatment on the glass surface or on the backfoil. Effects of the glass-cleaning method and surface texture are not obvious. Direct priming treatments used in the work did not improve, or even worsened, the adhesion. Aging of EVA by storage over~5 years reduced notably the adhesion strength. Lower adhesion strengths were observed for the blank (unformulated) EVA and non-EVA copolymers, such as poly(ethylene-co-methacrylate) (PEMA) or poly(ethylene-co-butylacrylate) (PEBA). Their adhesion strengths increased if the copolymers were cross-linked. Transparent fluoropolymer superstrates such as TefzelTM and DureflexTM films used for thin-film PV modules showed low adhesion strengths to the EVA at a level of~2 N/mm.« less

Bovine serum albumin release from novel chitosan-fluoro-aluminosilicate glass ionomer cement: stability and cytotoxicity studies.

PubMed

Limapornvanich, Araya; Jitpukdeebodintra, Suwanna; Hengtrakool, Chanothai; Kedjarune-Leggat, Ureporn

2009-09-01

This study aimed to evaluate the effect of adding chitosan (CS) to conventional glass ionomer cement (GIC) on protein release and its cytotoxicity. Bovine serum albumin (BSA) was used as the released protein from two glass ionomer formulations. One (GIC+BSA) contained fluoro-aluminosilicate glass mixed with BSA, and another (GIC:CS+BSA) used a similar glass and BSA with 20% chitosan. Six disc specimens per group (10mm in diameter, 2mm in height) were prepared and placed in phosphate buffer saline, which was replaced at various times over 2 weeks. The released protein was determined by a BCA assay. Cytotoxicity of the extracts from these materials for 1, 2 and 7 days to dental pulp cells was evaluated using MTT assay. The GIC:CS+BSA released a burst of BSA in the first 6h, and slowly released at different rates over the 2 weeks. GIC+BSA showed a similar result, but protein could not be detected at the 12h. The protein release rate of GIC:CS+BSA was significantly greater than GIC+BSA (P<0.01); nearly three times higher. The released BSA had the same molecular weight as evaluated by SDS-PAGE. From the MTT assay, the percentages of viable cells were significantly different and can be arranged as: GIC:CS+BSA>GIC:CS>GI+BSA>GI and the cytotoxicity was increased by time of extraction. Chitosan added in glass ionomer cement can prolong release of BSA as well as not increasing the toxicity to pulp cells. This material may be useful for protein delivery.

The regional cerebral blood flow changes in major depressive disorder with and without psychotic features.

PubMed

Gonul, Ali Saffet; Kula, Mustafa; Bilgin, Arzu Guler; Tutus, Ahmet; Oguz, Aslan

2004-09-01

Depressive patients with psychotic features demonstrate distinct biological abnormalities in the hypothalamic-pituitary-adrenal axis (HPA), dopaminergic activity, electroencephalogram sleep profiles and measures of serotonergic function when compared to nonpsychotic depressive patients. However, very few functional neuroimaging studies were specifically designed for studying the effects of psychotic features on neuroimaging findings in depressed patients. The objective of the present study was to compare brain Single Photon Emission Tomography (SPECT) images in a group of unmedicated depressive patients with and without psychotic features. Twenty-eight patients who fully met DSM-IV criteria for major depressive disorder (MDD, 12 had psychotic features) were included in the study. They were compared with 16 control subjects matched for age, gender and education. Both psychotic and nonpsychotic depressed patients showed significantly lower regional cerebral blood flow (rCBF) values in the left and right superior frontal cortex, and left anterior cingulate cortex compared to those of controls. In comparison with depressive patients without psychotic features (DwoPF), depressive patients with psychotic features (DwPF) showed significantly lower rCBF perfusion ratios in left parietal cortex, left cerebellum but had higher rCBF perfusion ratio in the left inferior frontal cortex and caudate nucleus. The present study showed that DwPF have a different rCBF pattern compared to patients without psychotic features. Abnormalities involving inferior frontal cortex, striatum and cerebellum may play an important role in the generation of psychotic symptoms in depression.

Simulated Waste Testing Of Glycolate Impacts On The 2H-Evaporator System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martino, C. J.

2013-08-13

Glycolic acid is being studied as a total or partial replacement for formic acid in the Defense Waste Processing Facility (DWPF) feed preparation process. After implementation, the recycle stream from DWPF back to the high-level waste tank farm will contain soluble sodium glycolate. Most of the potential impacts of glycolate in the tank farm were addressed via a literature review, but several outstanding issues remained. This report documents the non-radioactive simulant tests impacts of glycolate on storage and evaporation of Savannah River Site high-level waste. The testing for which non-radioactive simulants could be used involved the following: the partitioning ofmore » glycolate into the evaporator condensate, the impacts of glycolate on metal solubility, and the impacts of glycolate on the formation and dissolution of sodium aluminosilicate scale within the evaporator. The following are among the conclusions from this work: Evaporator condensate did not contain appreciable amounts of glycolate anion. Of all tests, the highest glycolate concentration in the evaporator condensate was 0.38 mg/L. A significant portion of the tests had glycolate concentration in the condensate at less than the limit of quantification (0.1 mg/L). At ambient conditions, evaporator testing did not show significant effects of glycolate on the soluble components in the evaporator concentrates. Testing with sodalite solids and silicon containing solutions did not show significant effects of glycolate on sodium aluminosilicate formation or dissolution.« less

Preparation and evaluation of a novel glass-ionomer cement with antibacterial functions.

PubMed

Xie, Dong; Weng, Yiming; Guo, Xia; Zhao, Jun; Gregory, Richard L; Zheng, Cunge

2011-05-01

The objective of this study was to use the newly synthesized poly(quaternary ammonium salt) (PQAS)-containing polyacid to formulate the light-curable glass-ionomer cements and study the effect of the PQAS on the compressive strength and antibacterial activity of the formed cements. The functional QAS and their constructed PQAS were synthesized, characterized and formulated into the experimental high-strength cements. Compressive strength (CS) and Streptococcus mutans viability were used to evaluate the mechanical strength and antibacterial activity of the cements. Fuji II LC cement was used as control. The specimens were conditioned in distilled water at 37°C for 24 h prior to testing. The effects of the substitute chain length, loading as well as grafting ratio of the QAS and aging on CS and S. mutans viability were investigated. All the PQAS-containing cements showed a significant antibacterial activity, accompanying with an initial CS reduction. The effects of the chain length, loading and grafting ratio of the QAS were significant. Increasing chain length, loading, grafting ratio significantly enhanced antibacterial activity but reduced the initial CS. Under the same substitute chain length, the cements containing QAS bromide were found to be more antibacterial than those containing QAS chloride although the CS values of the cements were not statistically different from each other, suggesting that we can use QAS bromide directly without converting bromide to chloride. The experimental cement showed less CS reduction and higher antibacterial activity than Fuji II LC. The long-term aging study suggests that the cements may have a long-lasting antibacterial function. This study developed a novel antibacterial glass-ionomer cement. Within the limitations of this study, it appears that the experimental cement is a clinically attractive dental restorative due to its high mechanical strength and antibacterial function. Published by Elsevier Ltd.

Preparation and evaluation of a novel star-shaped polyacid-constructed dental glass-ionomer system.

PubMed

Howard, Leah; Weng, Yiming; Xie, Dong

2014-06-01

The objective of this study was to synthesize and characterize novel star-shaped poly(acrylic acid-co-itaconic acid)s via chain-transfer radical polymerization technique, use these polyacids to formulate the resin-modified glass-ionomer cements, and evaluate the mechanical strengths of the formed cements The star-shaped poly(acrylic acid-co-itaconic acid)s were synthesized via a chain-transfer radical polymerization reaction using a newly synthesized star-shaped chain-transfer agent. The effects of MW, GM-tethering ratio, P/L ratio and aging on the compressive properties of the formed experimental cements were studied. Compressive, diametral tensile as well as flexural strengths were evaluated and compared to those of Fuji II and Fuji II LC cements. The star-shaped polyacids showed significantly lower viscosities in water as compared to their linear counterparts. The cements formulated with these novel polyacids showed significantly improved mechanical strengths i.e., 49% in yield strength, 41% in modulus, 25% in CS, 20% in DTS and 36% in FS, higher than commercial Fuji II LC. After aging in water for 30 days, the compressive strengths of the experimental cements were significantly changed with an increase of 29% in YS, 19% in modulus as well as 23% in CS and a decrease of 5% in toughness, indicating that aging in water enhances the salt-bridge formation and increases brittleness. A novel light-cured glass-ionomer cement system composed of the star-shaped poly(carboxylic acid)s has been developed via a cost-effective and time-efficient chain-transfer radical polymerization. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Is imidacloprid an effective alternative for controlling pyrethroid-resistant populations of Triatoma infestans (Hemiptera: Reduviidae) in the Gran Chaco ecoregion?

PubMed

Carvajal, Guillermo; Picollo, María Inés; Toloza, Ariel Ceferino

2014-09-01

The prevention of Chagas disease is based primarily on the chemical control of Triatoma infestans (Klug) using pyrethroid insecticides. However, high resistance levels, correlated with control failures, have been detected in Argentina and Bolivia. A previous study at our laboratory found that imidacloprid could serve as an alternative to pyrethroid insecticides. We studied the delayed toxicity of imidacloprid and the influence of the blood feeding condition of the insect on the toxicity of this insecticide; we also studied the effectiveness of various commercial imidacloprid formulations against a pyrethroid-resistant T. infestans population from the Gran Chaco ecoregion. Variations in the toxic effects of imidacloprid were not observed up to 72 h after exposure and were not found to depend on the blood feeding condition of susceptible and resistant individuals. Of the three different studied formulations of imidacloprid on glass and filter paper, only the spot-on formulation was effective. This formulation was applied to pigeons at doses of 1, 5, 20 and 40 mg/bird. The nymphs that fed on pigeons treated with 20 mg or 40 mg of the formulation showed a higher mortality rate than the control group one day and seven days post-treatment (p < 0.01). A spot-on formulation of imidacloprid was effective against pyrethroid-resistant T. infestans populations at the laboratory level.

Is imidacloprid an effective alternative for controlling pyrethroid-resistant populations of Triatoma infestans (Hemiptera: Reduviidae) in the Gran Chaco ecoregion?

PubMed Central

Carvajal, Guillermo; Picollo, María Inés; Toloza, Ariel Ceferino

2014-01-01

The prevention of Chagas disease is based primarily on the chemical control of Triatoma infestans (Klug) using pyrethroid insecticides. However, high resistance levels, correlated with control failures, have been detected in Argentina and Bolivia. A previous study at our laboratory found that imidacloprid could serve as an alternative to pyrethroid insecticides. We studied the delayed toxicity of imidacloprid and the influence of the blood feeding condition of the insect on the toxicity of this insecticide; we also studied the effectiveness of various commercial imidacloprid formulations against a pyrethroid-resistant T. infestans population from the Gran Chaco ecoregion. Variations in the toxic effects of imidacloprid were not observed up to 72 h after exposure and were not found to depend on the blood feeding condition of susceptible and resistant individuals. Of the three different studied formulations of imidacloprid on glass and filter paper, only the spot-on formulation was effective. This formulation was applied to pigeons at doses of 1, 5, 20 and 40 mg/bird. The nymphs that fed on pigeons treated with 20 mg or 40 mg of the formulation showed a higher mortality rate than the control group one day and seven days post-treatment (p < 0.01). A spot-on formulation of imidacloprid was effective against pyrethroid-resistant T. infestans populations at the laboratory level. PMID:25141281

Evaluation of soyscreen in an oil-based formulation for UV protection of Beauveria bassiana conidia.

PubMed

Behle, Robert W; Compton, David L; Laszlo, Joseph A; Shapiro-Ilan, David I

2009-10-01

Soyscreen oil was studied as a formulation ingredient to protect Beauveria bassiana (Balsamo) Vuillemin conidia from UV degradation. Feruloylated soy glycerides, referred to as Soyscreen oil, are biobased UV-absorbing molecules made by combining molecules of soybean oil with ferulic acid. Conidia stored in Soyscreen oil for 28 wk at 25, 30, and 35 degrees C retained viability as well as conidia stored in sunflower oil, demonstrating that Soyscreen did not adversely affect viability with prolonged storage. For samples applied to glass and exposed to simulated sunlight (xenon light), conidia in sunflower oil with or without sunscreens (Soyscreen or oxyl methoxycinnimate) had similar conidia viability after exposure. These oil formulations retained conidia viability better than conidia applied as an aqueous treatment. However, the 10% Soyscreen oil formulation applied to field grown cabbage (Brassica oleracea L.) and bean (Phaseolus vulgaris L.) plants, did not improve residual insecticidal activity compared with aqueous applications of unformulated conidia or two commercial formulations when assayed against Trichoplusia ni (Hübner) larvae. Our results suggest that the oil applications lose UV protection because the oil was absorbed by the leaf. This conclusion was supported in subsequent laboratory exposures of conidia in oil-based formulations with UV screens applied to cabbage leaves or balsa wood, which lost protection as measured by decreased viability of conidia when exposed to simulated sunlight. As a result, additional formulation techniques such as encapsulation to prevent separation of the protective oil from the conidia may be required to extend protection when oil formulations are applied in the field.

Alternate Reductant Cold Cap Evaluation Furnace Phase II Testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, F. C.; Stone, M. E.; Miller, D. H.

2014-09-03

Savannah River Remediation (SRR) conducted a Systems Engineering Evaluation (SEE) to determine the optimum alternate reductant flowsheet for the Defense Waste Processing Facility (DWPF). Specifically, two proposed flowsheets (nitric–formic–glycolic and nitric–formic–sugar) were evaluated based upon results from preliminary testing. Comparison of the two flowsheets among evaluation criteria indicated a preference towards the nitric–formic–glycolic flowsheet. Further research and development of this flowsheet eliminated the formic acid, and as a result, the nitric–glycolic flowsheet was recommended for further testing. Based on the development of a roadmap for the nitric–glycolic acid flowsheet, Waste Solidification Engineering (WS-E) issued a Technical Task Request (TTR) tomore » address flammability issues that may impact the implementation of this flowsheet. Melter testing was requested in order to define the DWPF flammability envelope for the nitric-glycolic acid flowsheet. The Savannah River National Laboratory (SRNL) Cold Cap Evaluation Furnace (CEF), a 1/12 th scale DWPF melter, was selected by the SRR Alternate Reductant project team as the melter platform for this testing. The overall scope was divided into the following sub-tasks as discussed in the Task Technical and Quality Assurance Plan (TTQAP): Phase I - A nitric–formic acid flowsheet melter test (unbubbled) to baseline the CEF cold cap and vapor space data to the benchmark melter flammability models; Phase II - A nitric–glycolic acid flowsheet melter test (unbubbled and bubbled) to: Define new cold cap reactions and global kinetic parameters in support of the melter flammability model development; Quantify off-gas surging potential of the feed; Characterize off-gas condensate for complete organic and inorganic carbon species. After charging the CEF with cullet from Phase I CEF testing, the melter was slurry-fed with glycolic flowsheet based SB6-Frit 418 melter feed at 36% waste loading and was operated continuously for 25 days. Process data was collected throughout testing and included melter operation parameters and off-gas chemistry. In order to generate off-gas data in support of the flammability model development for the nitric-glycolic flowsheet, vapor space steady state testing in the range of ~300-750°C was conducted under the following conditions, (i) 100% (nominal and excess antifoam levels) and 125% stoichiometry feed and (ii) with and without argon bubbling. Adjustments to feed rate, heater outputs and purge air flow were necessary in order to achieve vapor space temperatures in this range. Surge testing was also completed under nominal conditions for four days with argon bubbling and one day without argon bubbling.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiedenman, B. J.; White, T. L.; Mahannah, R. N.

Ion Chromatography (IC) is the principal analytical method used to support studies of Sludge Reciept and Adjustment Tank (SRAT) chemistry at DWPF. A series of prior analytical ''Round Robin'' (RR) studies included both supernate and sludge samples from SRAT simulant, previously reported as memos, are tabulated in this report.2,3 From these studies it was determined to standardize IC column size to 4 mm diameter, eliminating the capillary column from use. As a follow on test, the DWPF laboratory, the PSAL laboratory, and the AD laboratory participated in the current analytical RR to determine a suite of anions in SRAT simulantmore » by IC, results also are tabulated in this report. The particular goal was to confirm the laboratories ability to measure and quantitate glycolate ion. The target was + or - 20% inter-lab agreement of the analyte averages for the RR. Each of the three laboratories analyzed a batch of 12 samples. For each laboratory, the percent relative standard deviation (%RSD) of the averages on nitrate, glycolate, and oxalate, was 10% or less. The three laboratories all met the goal of 20% relative agreement for nitrate and glycolate. For oxalate, the PSAL laboratory reported an average value that was 20% higher than the average values reported by the DWPF laboratory and the AD laboratory. Because of this wider window of agreement, it was concluded to continue the practice of an additional acid digestion for total oxalate measurement. It should also be noted that large amounts of glycolate in the SRAT samples will have an impact on detection limits of near eluting peaks, namely Fluoride and Formate. A suite of scoping experiments are presented in the report to identify and isolate other potential interlaboratory disceprancies. Specific ion chromatography inter-laboratory method conditions and differences are tabulated. Most differences were minor but there are some temperature control equipment differences that are significant leading to a recommendation of a heated jacket for analytical columns that are remoted for use in radiohoods. A suggested method improvement would be to implement column temperture control at a temperature slightly above ambient to avoid peak shifting due to temperature fluctuations. Temperature control in this manner would improve short and longer term peak retention time stability. An unknown peak was observed during the analysis of glycolic acid and SRAT simulant. The unknown peak was determined to best match diglycolic acid. The development of a method for acetate is summaraized, and no significant amount of acetate was observed in the SRAT products tested. In addition, an alternative Gas Chromatograph (GC) method for glycolate is summarized.« less

ACTUAL WASTE TESTING OF GYCOLATE IMPACTS ON THE SRS TANK FARM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martino, C.

2014-05-28

Glycolic acid is being studied as a replacement for formic acid in the Defense Waste Processing Facility (DWPF) feed preparation process. After implementation, the recycle stream from DWPF back to the high-level waste Tank Farm will contain soluble sodium glycolate. Most of the potential impacts of glycolate in the Tank Farm were addressed via a literature review and simulant testing, but several outstanding issues remained. This report documents the actual-waste tests to determine the impacts of glycolate on storage and evaporation of Savannah River Site high-level waste. The objectives of this study are to address the following: Determine the extentmore » to which sludge constituents (Pu, U, Fe, etc.) dissolve (the solubility of sludge constituents) in the glycolate-containing 2H-evaporator feed. Determine the impact of glycolate on the sorption of fissile (Pu, U, etc.) components onto sodium aluminosilicate solids. The first objective was accomplished through actual-waste testing using Tank 43H and 38H supernatant and Tank 51H sludge at Tank Farm storage conditions. The second objective was accomplished by contacting actual 2H-evaporator scale with the products from the testing for the first objective. There is no anticipated impact of up to 10 g/L of glycolate in DWPF recycle to the Tank Farm on tank waste component solubilities as investigated in this test. Most components were not influenced by glycolate during solubility tests, including major components such as aluminum, sodium, and most salt anions. There was potentially a slight increase in soluble iron with added glycolate, but the soluble iron concentration remained so low (on the order of 10 mg/L) as to not impact the iron to fissile ratio in sludge. Uranium and plutonium appear to have been supersaturated in 2H-evaporator feed solution mixture used for this testing. As a result, there was a reduction of soluble uranium and plutonium as a function of time. The change in soluble uranium concentration was independent of added glycolate concentration. The change in soluble plutonium content was dependent on the added glycolate concentration, with higher levels of glycolate (5 g/L and 10 g/L) appearing to suppress the plutonium solubility. The inclusion of glycolate did not change the dissolution of or sorption onto actual-waste 2H-evaporator pot scale to an extent that will impact Tank Farm storage and concentration. The effects that were noted involved dissolution of components from evaporator scale and precipitation of components onto evaporator scale that were independent of the level of added glycolate.« less

Final Report - LAW Envelope A and B Glass Formulations Testing in Increase Waste Loading. VSL-06R6900-1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, Albert A.; Joseph, I.; Muller, I. S.

This report describes the results of testing specified by the Test Plan VSL-06R6900-1 Rev 0. The work was performed in compliance with quality assurance requirements specified in the Test Plan. Results required by the Test Plan are reported. The test results and this report have been reviewed for correctness, technical adequacy, completeness, and accuracy.

Effect of polymer properties and adherend surfaces on adhesion

NASA Technical Reports Server (NTRS)

Dwight, D. W.; Wightman, J. P.

1976-01-01

High temperature polymer surface characteristics associated with joint strength were evaluated. Selected samples represented composite adherends, aluminum filler and fiber glass carrier cloth. Detailed analysis of fractured joint surfaces revealed unique characteristics typical of the specific adhesive formulations and test conditions. A fracture mechanism model was developed for correlating macroscopic shear strength and microstructure of fracture surfaces. Applications were made to unpublished data on polyimides and fluoropolymers.

Setting of commercial glass ionomer cement Fuji IX by (27)Al and (19)F MAS-NMR.

PubMed

Munhoz, Tais; Karpukhina, Natalia; Hill, Robert G; Law, Robert V; De Almeida, L H

2010-04-01

To investigate the long term setting reaction in the glass ionomer restorative, Fuji IX, by monitoring the structural evolution of aluminium and fluorine species using (27)Al and (19)F MAS-NMR spectroscopy. Fuji IX cements aged from 5min up to 3 months were prepared according to the manufacturer instructions from the commercial material. The (27)Al and (19)F MAS-NMR studies were carried out on powders made after terminating the setting reaction. (27)Al MAS-NMR results show conversion of aluminium from the glass phase, where it has coordination number four, Al(IV), into the cement matrix where it has a coordination number of six, Al(VI). At least two different Al(VI) species were detected at short ageing time cements. Assignment of these species is discussed and compared with the data from other sources. The possibility for a condensed aluminium species [Al(13)(OH)(24)(H(2)O)(12)](7+) to form is considered. The ratio of aluminium in the cement, Al(VI), to the remaining unreacted in glass has been evaluated by deconvolution of the spectra. Various theoretical ratios of aluminium species in the cement matrix to the unreacted ones remaining in glass have been estimated. The (19)F MAS-NMR spectra are identical for the glass and cements at the early times and contain a dominant signal assigned to Al-F-Sr(n). The data confirms that the conversion of aluminium is a diffusion-controlled process at early stage less than 1h and it is largely complete between 1 and 6h. The comparison with the experimental data shows that the majority of aluminium cations do not form tricarboxylates but are coordinated with one or two carboxylic groups and other ligands. Insufficient amount of water and excess of glass in this cement formulation affect glass degradation mechanism. Crown Copyright 2009. Published by Elsevier Ltd. All rights reserved.

Effect of boron oxide addition on the viscosity-temperature behaviour and structure of phosphate-based glasses.

PubMed

Sharmin, Nusrat; Hasan, Muhammad S; Rudd, Chris D; Boyd, Daniel; Werner-Zwanziger, Ulrike; Ahmed, Ifty; Parsons, Andrew J

2017-05-01

In this study, nine phosphate-based glass formulations from the system P 2 O 5 -CaO-Na 2 O-MgO-B 2 O 3 were prepared with P 2 O 5 content fixed as 40, 45 and 50 mol%, where Na 2 O was replaced by 5 and 10 mol% B 2 O 3 and MgO and CaO were fixed to 24 and 16 mol%, respectively. The effect of B 2 O 3 addition on the viscosity-temperature behaviour, fragility index and structure of the glasses was investigated. The composition of the glasses was confirmed by ICP-AES. The viscosity-temperature behaviour of the glasses were measured using beam-bending and parallel -plate viscometers. The viscosity of the glasses investigated was found to shift to higher temperature with increasing B 2 O 3 content. The kinetic fragility parameter, m and F 1/2 , estimated from the viscosity curve were found to decease with increasing B 2 O 3 content. The structural analysis was achieved by a combination of Fourier transform infrared spectroscopy and solid state nuclear magnetic resonance. 31 P solid-state magic-angle-spinning nuclear magnetic resonance (MAS-NMR) showed that the local structure of the glasses changes with increasing B 2 O 3 content. As B 2 O 3 was added to the glass systems, the phosphate connectivity increases as the as the Q 1 units transforms into Q 2 units. The 11 B NMR results confirmed the presence of tetrahedral boron (BO 4 ) units for all the compositions investigated. Structural analysis indicates an increasing level of cross-linking with increasing B 2 O 3 content. Evidence of the presence of P-O-B bonds was also observed from the FTIR and 31 P NMR analysis. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 764-777, 2017. © 2016 Wiley Periodicals, Inc.

Preparation and In Vitro/Ex Vivo Evaluation of Moxifloxacin-Loaded PLGA Nanosuspensions for Ophthalmic Application.

PubMed

Mudgil, Meetali; Pawar, Pravin K

2013-01-01

The aim of the present investigation was to prepare a colloidal ophthalmic formulation to improve the residence time of moxifloxacin. Moxifloxacin-loaded poly(dl-lactide-co-glycolide) (PLGA) nanosuspensions were prepared by using the solvent evaporation technique. The nanosuspensions were characterised physically by using different techniques like particle size, zeta potential, FTIR, DSC, and XRD analysis. In vitro and ex vivo studies of nanosuspensions were carried out using a modified USP dissolution apparatus and all-glass Franz diffusion cells, respectively. The antibacterial activities of the nanosuspension and marketed formulations were performed against S. aureus and P. aeroginosa. The moxifloxacin-loaded PLGA nanosuspensions showed uniform particle size, ranging between 164-490 nm with negative zeta potential for all batches. The percentage entrapment efficiency of the drug-loaded nano-suspension was found to be between 84.09 to 92.05%. In vitro drug release studies suggest that all of the formulations showed extended drug release profiles and follow Korsemeyer-Peppas release kinetics. In vitro corneal permeability was found to be comparable with that of the marketed formulation across isolated goat cornea, indicating the suitability of the nanosuspension formulation in the ophthalmic delivery of moxifloxacin. The optimised nano-suspension was found to be more active against S. aureus and P. aeruginosa compared to the marketed eye drops.

Development of a Mechanistic-Based Healing Model for Self-Healing Glass Seals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Wei; Stephens, Elizabeth V.; Sun, Xin

Self-healing glass, a recent development of hermetic sealant materials, has the ability to effectively repair damage when heated to elevated temperatures; thus, able to extend its service life. Since crack healing morphological changes in the glass material are usually temperature and stress dependent, quantitative studies to determine the effects of thermo-mechanical conditions on the healing behavior of the self-healing glass sealants are extremely useful to accommodate the design and optimization of the sealing systems within SOFCs. The goal of this task is to develop a mechanistic-based healing model to quantify the stress and temperature dependent healing behavior. A two-step healingmore » mechanism was developed and implemented into finite element (FE) models through user-subroutines. Integrated experimental/kinetic Monte Carlo (kMC) simulation methodology was taken to calibrate the model parameters. The crack healing model is able to investigate the effects of various thermo-mechanical factors; therefore, able to determine the critical conditions under which the healing mechanism will be activated. Furthermore, the predicted results can be used to formulate the continuum damage-healing model and to assist the SOFC stack level simulations in predicting and evaluating the effectiveness and the performance of various engineering seal designs.« less

Investigating factors leading to fogging of glass vials in lyophilized drug products.

PubMed

Abdul-Fattah, Ahmad M; Oeschger, Richard; Roehl, Holger; Bauer Dauphin, Isabelle; Worgull, Martin; Kallmeyer, Georg; Mahler, Hanns-Christian

2013-10-01

Vial "Fogging" is a phenomenon observed after lyophilization due to drug product creeping upwards along the inner vial surface. After the freeze-drying process, a haze of dried powder is visible inside the drug product vial, making it barely acceptable for commercial distribution from a cosmetic point of view. Development studies were performed to identify the root cause for fogging during manufacturing of a lyophilized monoclonal antibody drug product. The results of the studies indicate that drug product creeping occurs during the filling process, leading to vial fogging after lyophilization. Glass quality/inner surface, glass conversion/vial processing (vial "history") and formulation excipients, e.g., surfactants (three different surfactants were tested), all affect glass fogging to a certain degree. Results showed that the main factor to control fogging is primarily the inner vial surface hydrophilicity/hydrophobicity. While Duran vials were not capable of reliably improving the level of fogging, hydrophobic containers provided reliable means to improve the cosmetic appearance due to reduction in fogging. Varying vial depyrogenation treatment conditions did not lead to satisfying results in removal of the fogging effect. Processing conditions of the vial after filling with drug product had a strong impact on reducing but not eliminating fogging. Copyright © 2013 Elsevier B.V. All rights reserved.

Common display performance requirements for military and commercial aircraft product lines

NASA Astrophysics Data System (ADS)

Hoener, Steven J.; Behrens, Arthur J.; Flint, John R.; Jacobsen, Alan R.

2001-09-01

Obtaining high quality Active Matrix Liquid Crystal (AMLCD) glass to meet the needs of the commercial and military aerospace business is a major challenge, at best. With the demise of all domestic sources of AMLCD substrate glass, the industry is now focused on overseas sources, which are primarily producing glass for consumer electronics. Previous experience with ruggedizing commercial glass leads to the expectation that the aerospace industry can leverage off the commercial market. The problem remains, while the commercial industry is continually changing and improving its products, the commercial and military aerospace industries require stable and affordable supplies of AMLCD glass for upwards of 20 years to support production and maintenance operations. The Boeing Engineering and Supplier Management Process Councils have chartered a group of displays experts from multiple aircraft product divisions within the Boeing Company, the Displays Process Action Team (DPAT), to address this situation from an overall corporate perspective. The DPAT has formulated a set of Common Displays Performance Requirements for use across the corporate line of commercial and military aircraft products. Though focused on the AMLCD problem, the proposed common requirements are largely independent of display technology. This paper describes the strategy being pursued within the Boeing Company to address the AMLCD supply problem and details the proposed implementation process, centered on common requirements for both commercial and military aircraft displays. Highlighted in this paper are proposed common, or standard, display sizes and the other major requirements established by the DPAT, along with the rationale for these requirements.

A continuum thermo-inelastic model for damage and healing in self-healing glass materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Wei; Sun, Xin; Koeppel, Brian J.

Self-healing glass, a recent advancement in the class of smart sealing materials, has attracted great attention from both research and industrial communities because of its unique capability of repairing itself at elevated temperatures. However, further development and optimization of this material rely on a more fundamental and thorough understanding of its essential thermo-mechanical response characteristics, which is also pivotal in predicting the coupling and interactions between the nonlinear stress and temperature dependent damage and healing behaviors. In the current study, a continuum three-dimensional thermo-inelastic damage-healing constitutive framework has been developed for the compliant self-healing glass material. The important feature ofmore » the present model is that various phenomena governing the mechanical degradation and recovery process, i.e. the nucleation, growth, and healing of the cracks and pores, are described with distinct mechanism-driven kinetics, where the healing constitutive relations are propagated from lower-length scale simulations. The proposed formulations are implemented into finite element analyses and the effects of various loading conditions and material properties on the material’s mechanical resistance are investigated.« less

Degradation in PV Encapsulant Strength of Attachment: An Interlaboratory Study Towards a Climate-Specific Test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, David C.; Annigoni, Eleonora; Ballion, Amal

Reduced strength of attachment of the encapsulant resulting from the outdoor environment, including ultraviolet (UV) radiation, may decrease photovoltaic (PV) module lifetime by enabling widespread corrosion of internal components. To date, few studies exist showing how the adhesion of PV components varies with environmental stress. We have conducted an interlaboratory experiment to provide an understanding that will be used to develop climatic specific module tests. Factors examined in the study included the UV light source (lamp type), temperature, and humidity to be proposed for use in accelerated aging tests. A poly (ethylene-co-vinyl acetate) (EVA) formulation often used in veteran PVmore » installations was studied using a compressive shear test - to quantify the strength of attachment at the EVA/glass interface. Replicate laminated glass/polymer/glass coupon specimens were weathered at 12 institutions using a variety of indoor chambers or field aging. Shear strength, shear strain, and toughness were measured using a mechanical load-frame for the compressive shear test, with subsequent optical imaging and electron microscopy of the separated surfaces.« less

Degradation in PV Encapsulation Strength of Attachment: An Interlaboratory Study Towards a Climate-Specific Test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, David; Annigoni, Eleonora; Ballion, Amal

Reduced strength of attachment of the encapsulant resulting from the outdoor environment, including ultraviolet (UV) radiation, may decrease photovoltaic (PV) module lifetime by enabling widespread corrosion of internal components. To date, few studies exist showing how the adhesion of PV components varies with environmental stress. We have conducted an interlaboratory experiment to provide an understanding that will be used to develop climatic specific module tests. Factors examined in the study included the UV light source (lamp type), temperature, and humidity to be proposed for use in accelerated aging tests. A poly (ethylene-co-vinyl acetate) (EVA) formulation often used in veteran PVmore » installations was studied using a compressive shear test - to quantify the strength of attachment at the EVA/glass interface. Replicate laminated glass/polymer/glass coupon specimens were weathered at 12 institutions using a variety of indoor chambers or field aging. Shear strength, shear strain, and toughness were measured using a mechanical load-frame for the compressive shear test, with subsequent optical imaging and electron microscopy of the separated surfaces.« less

Degradation in PV Encapsulant Strength of Attachment: An Interlaboratory Study Towards a Climate-Specific Test: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, David C.; Annigoni, Eleonora; Ballion, Amal

Reduced strength of attachment of the encapsulant resulting from outdoor environment, including ultraviolet (UV) radiation, may decrease photovoltaic (PV) module lifetime by enabling widespread corrosion of internal components. To date, few studies exist showing how the adhesion of PV components varies with environmental stress. We have conducted an interlaboratory experiment to provide an understanding that will be used to develop climatic specific module tests. Factors examined in the study included the UV light source (lamp type), temperature, and humidity to be proposed for use in accelerated aging tests. A poly (ethylene-co-vinyl acetate) (EVA) formulation often used in veteran PV installationsmore » was studied using a compressive shear test - to quantify the strength of attachment at the EVA/glass interface. Replicate laminated glass/polymer/glass coupon specimens were weathered at 12 institutions using a variety of indoor chambers or field aging. Shear strength, shear strain, and toughness were measured using a mechanical load-frame for the compressive shear test, with subsequent optical imaging and electron microscopy of the separated surfaces.« less

EFFECTS OF TRITIUM GAS EXPOSURE ON THE GLASS TRANSITION TEMPERATURE OF EPDM ELASTOMER AND ON THE CONDUCTIVITY OF POLYANILINE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, E; Marie Kane, M

2008-12-12

Four formulations of EPDM (ethylene-propylene diene monomer) elastomer were exposed to tritium gas initially at one atmosphere and ambient temperature for between three and four months in closed containers. Material properties that were characterized include density, volume, mass, appearance, flexibility, and dynamic mechanical properties. The glass transition temperature was determined by analysis of the dynamic mechanical property data per ASTM standards. EPDM samples released significant amounts of gas when exposed to tritium, and the glass transition temperature increased by about 3 C. during the exposure. Effects of ultraviolet and gamma irradiation on the surface electrical conductivity of two types ofmore » polyaniline films are also documented as complementary results to planned tritium exposures. Future work will determine the effects of tritium gas exposure on the electrical conductivity of polyaniline films, to demonstrate whether such films can be used as a sensor to detect tritium. Surface conductivity was significantly reduced by irradiation with both gamma rays and ultraviolet light. The results of the gamma and UV experiments will be correlated with the tritium exposure results.« less

LaRC(TM)-IA Copolyimides

NASA Technical Reports Server (NTRS)

St. Clair, Terry L.; Chang, Alice C.

1995-01-01

Copolyimides modified versions of LaRC(TM)-IA thermoplastic polyimide formulated by incorporating moieties of 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) and, alternatively, isophthaloyldiphthalic anhydride (IDPA) into LaRC(TM)-IA polymer backbones. Exhibit higher glass-transition temperatures and retain greater fractions of lower-temperature shear moduli at higher temperatures. Copolyimides spun into fibers or used as adhesives, molding powders, or matrix resins in many applications, especially in fabrication of strong, lightweight structural components of aircraft.

Environmentally Friendly Bio-Based Vinyl Ester Resins for Military Composite Structures

DTIC Science & Technology

2008-12-01

composites, fatty acid , vinyl ester 9. Distribution $tatement (requr’iedl lsmanuscript subjectto export control? E ruo I yes Circfe appropriate l tter and...resins is to replace some or all of the styrene with fatty acid -based monomers. These fatty acid vinyl ester resins allow for the formulation of high...validation studies have been performed, showing that the fatty acid -based resins have sufficient, modulus, strength, glass transition temperature, and

Fire-through Ag contact formation for crystalline Si solar cells using single-step inkjet printing.

PubMed

Kim, Hyun-Gang; Cho, Sung-Bin; Chung, Bo-Mook; Huh, Joo-Youl; Yoon, Sam S

2012-04-01

Inkjet-printed Ag metallization is a promising method of forming front-side contacts on Si solar cells due to its non-contact printing nature and fine grid resolution. However, conventional Ag inks are unable to punch through the SiN(x) anti-reflection coating (ARC) layer on emitter Si surfaces. In this study, a novel formulation of Ag ink is examined for the formation of fire-through contacts on a SiN(x)-coated Si substrate using the single-step printing of Ag ink, followed by rapid thermal annealing at 800 degrees C. In order to formulate Ag inks with fire-through contact formation capabilities, a liquid etching agent was first formulated by dissolving metal nitrates in an organic solvent and then mixing the resulting solution with a commercial Ag nanoparticle ink at various volume ratios. During the firing process, the dissolved metal nitrates decomposed into metal oxides and acted in a similar manner to the glass frit contained in Ag pastes for screen-printed Ag metallization. The newly formulated ink with a 1 wt% loading ratio of metal oxides to Ag formed finely distributed Ag crystallites on the Si substrate after firing at 800 degrees C for 1 min.

Stability of Prednisone in Oral Mix Suspending Vehicle.

PubMed

Friciu, Mihaela; Plourde, Kevin; Leclair, Grégoire; Danopoulos, Panagiota; Savji, Taslim

2015-01-01

The stability of prednisone (5 mg/mL) formulated as a suspension in Oral Mix vehicle was evaluated. Oral Mix is a novel oral, dye-free suspending vehicle developed by Medisca Pharmaceutique Inc. for preparation of extemporaneous dosage forms. This drug was chosen based on its high frequency of prescription among the pediatric population. Suspensions were prepared from both pure active and commercial tablets utilizing two different container closures: amber glass bottles and polypropylene syringes (PreciseDose Dispenser Medisca Pharmaceutique Inc.). Formulations were stored at 5°C or 25°C and organoleptic properties, pH, and concentration were evaluated at predetermined time points up to 90 days. Validated stability-indicating high-performance liquid chromatography methods were developed. Beyond-use date was evaluated by statistical analysis of the overall degradation trend. Prednisone was stable for at least 90 days at 25°C. No changes in organoleptic properties or pH were observed for either of the formulations, and the global stability was roughly equivalent and sometimes superior to the stability of the same drugs in other previously used vehicles. Thus, Oral Mix was found to be a suitable dye-free vehicle for extemporaneous formulations.

Evaluation of Beeswax Influence on Physical Properties of Lipstick Using Instrumental and Sensory Methods.

PubMed

Kasparaviciene, Giedre; Savickas, Arunas; Kalveniene, Zenona; Velziene, Saule; Kubiliene, Loreta; Bernatoniene, Jurga

2016-01-01

The aim of this study was to optimize the lipsticks formulation according to the physical properties and sensory attributes and investigate the relationship between instrumental and sensory analyses and evaluate the influence of the main ingredients, beeswax and oil, with analysis of lipsticks properties. Central composite design was used to optimize the mixture of oils and beeswax and cocoa butter for formulation of lipsticks. Antioxidant activity was evaluated by DPPH free radical scavenging method spectrophotometrically. Physical properties of lipsticks melting point were determined in a glass tube; the hardness was investigated with texture analyzer. Sensory analysis was performed with untrained volunteers. The optimized mixture of sea buckthorn oil and grapeseed oil mixture ratio 13.96 : 6.18 showed the highest antioxidative activity (70 ± 0.84%) and was chosen for lipstick formulation. According to the sensory and instrumental analysis results, optimal ingredients amounts for the lipstick were calculated: 57.67% mixture of oils, 19.58% beeswax, and 22.75% cocoa butter. Experimentally designed and optimized lipstick formulation had good physical properties and high scored sensory evaluation. Correlation analysis showed a significant relationship between sensory and instrumental evaluations.

Evaluation of Beeswax Influence on Physical Properties of Lipstick Using Instrumental and Sensory Methods

PubMed Central

Kasparaviciene, Giedre; Savickas, Arunas; Kalveniene, Zenona; Velziene, Saule; Kubiliene, Loreta

2016-01-01

The aim of this study was to optimize the lipsticks formulation according to the physical properties and sensory attributes and investigate the relationship between instrumental and sensory analyses and evaluate the influence of the main ingredients, beeswax and oil, with analysis of lipsticks properties. Central composite design was used to optimize the mixture of oils and beeswax and cocoa butter for formulation of lipsticks. Antioxidant activity was evaluated by DPPH free radical scavenging method spectrophotometrically. Physical properties of lipsticks melting point were determined in a glass tube; the hardness was investigated with texture analyzer. Sensory analysis was performed with untrained volunteers. The optimized mixture of sea buckthorn oil and grapeseed oil mixture ratio 13.96 : 6.18 showed the highest antioxidative activity (70 ± 0.84%) and was chosen for lipstick formulation. According to the sensory and instrumental analysis results, optimal ingredients amounts for the lipstick were calculated: 57.67% mixture of oils, 19.58% beeswax, and 22.75% cocoa butter. Experimentally designed and optimized lipstick formulation had good physical properties and high scored sensory evaluation. Correlation analysis showed a significant relationship between sensory and instrumental evaluations. PMID:27994631

Electrical transport properties of CuXSn1-X metallic glasses

NASA Astrophysics Data System (ADS)

Vora, A. M.; Gajjar, P. N.

2018-05-01

In the present paper, we report the electrical resistivity (ρ), the thermoelectric power (TEP) and thermal conductivity (σ) of CuXSn1-X metallic glasses computed from Faber-Ziman formulation with Percus-Yevic (PY) hard sphere structure factors of Ashcroft and Langreth. Our well-recognized model potential is used to represent ionic interaction for the first time with seven local field correction functions due to Hartree (H), Hubbard-Sham (HS), Vashishta-Singwi (VS), Taylor (T), Ichimaru-Utsumi (IU), Farid et al. (F) and Sarkar et al. (S) in the present computation and found suitable for such study. The percentile influence of various local field corrections with respect to Hartree (H) is found in the range of 17.35%-71.55%. It is concluded that, the comparison of present and experimental findings of electrical resistivity (ρ) is highly promising.

Thermal shock fracture in cross-ply fibre-reinforced ceramic-matrix composites

NASA Astrophysics Data System (ADS)

Kastritseas, C.; Smith, P. A.; Yeomans, J. A.

2010-11-01

The onset of matrix cracking due to thermal shock in a range of simple and multi-layer cross-ply laminates comprising a calcium aluminosilicate (CAS) matrix reinforced with Nicalon® fibres is investigated analytically. A comprehensive stress analysis under conditions of thermal shock, ignoring transient effects, is performed and fracture criteria based on either a recently derived model for the thermal shock resistance of unidirectional Nicalon®/glass ceramic-matrix composites or fracture mechanics considerations are formulated. The effect of material thickness on the apparent thermal shock resistance is also modelled. Comparison with experimental results reveals that the accuracy of the predictions is satisfactory and the reasons for some discrepancies are discussed. In addition, a theoretical argument based on thermal shock theory is formulated to explain the observed cracking patterns.

SMA Hybrid Composites for Dynamic Response Abatement Applications

NASA Technical Reports Server (NTRS)

Turner, Travis L.

2000-01-01

A recently developed constitutive model and a finite element formulation for predicting the thermomechanical response of Shape Memory Alloy (SMA) hybrid composite (SMAHC) structures is briefly described. Attention is focused on constrained recovery behavior in this study, but the constitutive formulation is also capable of modeling restrained or free recovery. Numerical results are shown for glass/epoxy panel specimens with embedded Nitinol actuators subjected to thermal and acoustic loads. Control of thermal buckling, random response, sonic fatigue, and transmission loss are demonstrated and compared to conventional approaches including addition of conventional composite layers and a constrained layer damping treatment. Embedded SMA actuators are shown to be significantly more effective in dynamic response abatement applications than the conventional approaches and are attractive for combination with other passive and/or active approaches.

TRITIUM EFFECTS ON DYNAMIC MECHANICAL PROPERTIES OF POLYMERIC MATERIALS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, E

2008-11-12

Dynamic mechanical analysis has been used to characterize the effects of tritium gas (initially 1 atm. pressure, ambient temperature) exposure over times up to 2.3 years on several thermoplastics-ultrahigh molecular weight polyethylene (UHMW-PE), polytetrafluoroethylene (PTFE), and Vespel{reg_sign} polyimide, and on several formulations of elastomers based on ethylene propylene diene monomer (EPDM). Tritium exposure stiffened the elastic modulus of UHMW-PE up to about 1 year and then softened it, and reduced the viscous response monotonically with time. PTFE initially stiffened, however the samples became too weak to handle after nine months exposure. The dynamic properties of Vespel{reg_sign} were not affected. Themore » glass transition temperature of the EPDM formulations increased approximately 4 C. following three months tritium exposure.« less

Defense Waste Processing Facility Canister Closure Weld Current Validation Testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Korinko, P. S.; Maxwell, D. N.

Two closure welds on filled Defense Waste Processing Facility (DWPF) canisters failed to be within the acceptance criteria in the DWPF operating procedure SW4-15.80-2.3 (1). In one case, the weld heat setting was inadvertently provided to the canister at the value used for test welds (i.e., 72%) and this oversight produced a weld at a current of nominally 210 kA compared to the operating procedure range (i.e., 82%) of 240 kA to 263 kA. The second weld appeared to experience an instrumentation and data acquisition upset. The current for this weld was reported as 191 kA. Review of the datamore » from the Data Acquisition System (DAS) indicated that three of the four current legs were reading the expected values, approximately 62 kA each, and the fourth leg read zero current. Since there is no feasible way by further examination of the process data to ascertain if this weld was actually welded at either the target current or the lower current, a test plan was executed to provide assurance that these Nonconforming Welds (NCWs) meet the requirements for strength and leak tightness. Acceptance of the welds is based on evaluation of Test Nozzle Welds (TNW) made specifically for comparison. The TNW were nondestructively and destructively evaluated for plug height, heat tint, ultrasonic testing (UT) for bond length and ultrasonic volumetric examination for weld defects, burst pressure, fractography, and metallography. The testing was conducted in agreement with a Task Technical and Quality Assurance Plan (TTQAP) (2) and applicable procedures.« less

Computational prediction of formulation strategies for beyond-rule-of-5 compounds.

PubMed

Bergström, Christel A S; Charman, William N; Porter, Christopher J H

2016-06-01

The physicochemical properties of some contemporary drug candidates are moving towards higher molecular weight, and coincidentally also higher lipophilicity in the quest for biological selectivity and specificity. These physicochemical properties move the compounds towards beyond rule-of-5 (B-r-o-5) chemical space and often result in lower water solubility. For such B-r-o-5 compounds non-traditional delivery strategies (i.e. those other than conventional tablet and capsule formulations) typically are required to achieve adequate exposure after oral administration. In this review, we present the current status of computational tools for prediction of intestinal drug absorption, models for prediction of the most suitable formulation strategies for B-r-o-5 compounds and models to obtain an enhanced understanding of the interplay between drug, formulation and physiological environment. In silico models are able to identify the likely molecular basis for low solubility in physiologically relevant fluids such as gastric and intestinal fluids. With this baseline information, a formulation scientist can, at an early stage, evaluate different orally administered, enabling formulation strategies. Recent computational models have emerged that predict glass-forming ability and crystallisation tendency and therefore the potential utility of amorphous solid dispersion formulations. Further, computational models of loading capacity in lipids, and therefore the potential for formulation as a lipid-based formulation, are now available. Whilst such tools are useful for rapid identification of suitable formulation strategies, they do not reveal drug localisation and molecular interaction patterns between drug and excipients. For the latter, Molecular Dynamics simulations provide an insight into the interplay between drug, formulation and intestinal fluid. These different computational approaches are reviewed. Additionally, we analyse the molecular requirements of different targets, since these can provide an early signal that enabling formulation strategies will be required. Based on the analysis we conclude that computational biopharmaceutical profiling can be used to identify where non-conventional gateways, such as prediction of 'formulate-ability' during lead optimisation and early development stages, are important and may ultimately increase the number of orally tractable contemporary targets. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Formulation and preparation of Hanford Waste Treatment Plant direct feed low activity waste Effluent Management Facility core simulant

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCabe, Daniel J.; Nash, Charles A.; Adamson, Duane J.

The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream (LAW Melter Off-Gas Condensate, LMOGC) from the off-gas system. The baseline plan for disposition of this stream during full WTP operations is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility. However, during the Direct Feed LAW (DFLAW) scenario, planned disposition of this stream is to evaporate it in a new evaporator in the Effluent Management Facility (EMF) and then return it tomore » the LAW melter. It is important to understand the composition of the effluents from the melter and new evaporator so that the disposition of these streams can be accurately planned and accommodated. Furthermore, alternate disposition of the LMOGC stream would eliminate recycling of problematic components, and would enable less integrated operation of the LAW melter and the Pretreatment Facilities. Alternate disposition would also eliminate this stream from recycling within WTP when it begins operations and would decrease the LAW vitrification mission duration and quantity of glass waste, amongst the other problems such a recycle stream present. This LAW Melter Off-Gas Condensate stream will contain components that are volatile at melter temperatures and are problematic for the glass waste form, such as halides and sulfate. Because this stream will recycle within WTP, these components accumulate in the Melter Condensate stream, exacerbating their impact on the number of LAW glass containers that must be produced. Diverting the stream reduces the halides and sulfate in the recycled Condensate and is a key outcome of this work. This overall program examines the potential treatment and immobilization of this stream to enable alternative disposal. The objective of this task was to formulate and prepare a simulant of the LAW Melter Off-gas Condensate expected during DFLAW operations. That simulant can be used in evaporator testing to predict the composition of the effluents from the Effluent Management Facility (EMF) evaporator to aid in planning for their disposition. This document describes the method used to formulate a simulant of this LAW Melter Off-Gas Condensate stream, which, after pH adjustment, is the feed to the evaporator in the EMF.« less

Influence of Molecular Weight of Carriers and Processing Parameters on the Extrudability, Drug Release, and Stability of Fenofibrate Formulations Processed by Hot-Melt Extrusion.

PubMed

Alsulays, Bader B; Park, Jun-Bom; Alshehri, Sultan M; Morott, Joseph T; Alshahrani, Saad M; Tiwari, Roshan V; Alshetaili, Abdullah S; Majumdar, Soumyajit; Langley, Nigel; Kolter, Karl; Gryczke, Andreas; Repka, Michael A

2015-10-01

The objective of this study was to investigate the extrudability, drug release, and stability of fenofibrate (FF) formulations utilizing various hot-melt extrusion processing parameters and polyvinylpyrrolidone (PVP) polymers of various molecular weights. The different PVP grades selected for this study were Kollidon ® 12 PF (K12), Kollidon ® 30 (K30), and Kollidon ® 90 F (K90). FF was extruded with these polymers at three drug loadings (15%, 25%, and 35% w/w). Additionally, for FF combined with each of the successfully extruded PVP grades (K12 and K30), the effects of two levels of processing parameters for screw design, screw speed, and barrel temperature were assessed. It was found that the FF with (K90) was not extrudable up to 35% drug loading. With low drug loading, the polymer viscosity significantly influenced the release of FF. The crystallinity remaining was vital in the highest drug-loaded formulation dissolution profile, and the glass transition temperature of the polymer significantly affected its stability. Modifying the screw configuration resulted in more than 95% post-extrusion drug content of the FF-K30 formulations. In contrast to FF-K30 formulations, FF release and stability with K12 were significantly influenced by the extrusion temperature and screw speed.

Artificial neural networks to model formulation-property correlations in the process of inline-compounding on an injection moulding machine

NASA Astrophysics Data System (ADS)

Moritzer, Elmar; Müller, Ellen; Martin, Yannick; Kleeschulte, Rainer

2015-05-01

Today the global market poses great challenges for industrial product development. Complexity, diversity of variants, flexibility and individuality are just some of the features that products have to offer today. In addition, the product series have shorter lifetimes. Because of their high capacity for adaption, polymers are increasingly able to displace traditional materials such as wood, glass and metals from various fields of application. Polymers can only be used to substitute other materials, however, if they are optimally suited to the applications in question. Hence, product-specific material development is becoming increasingly important. Integrating the compounding step in the injection moulding process permits a more efficient and faster development process for a new polymer formulation, making it possible to create new product-specific materials. This process is called inline-compounding on an injection moulding machine. The entire process sequence is supported by software from Bayer Technology called Product Design Workbench (PDWB), which provides assistance in all the individual steps from data management, via analysis and model compilation, right through to the optimization of the formulation and the design of experiments. The software is based on artificial neural networks and can model the formulation-property correlations and thus enable different formulations to be optimized. In the study presented, the workflow and the modelling with the software are presented.

Scalable organic solvent free supercritical fluid spray drying process for producing dry protein formulations.

PubMed

Nuchuchua, O; Every, H A; Hofland, G W; Jiskoot, W

2014-11-01

In this study, we evaluated the influence of supercritical carbon dioxide (scCO2) spray drying conditions, in the absence of organic solvent, on the ability to produce dry protein/trehalose formulations at 1:10 and 1:4 (w/w) ratios. When using a 4L drying vessel, we found that decreasing the solution flow rate and solution volume, or increasing the scCO2 flow rate resulted in a significant reduction in the residual water content in dried products (Karl Fischer titration). The best conditions were then used to evaluate the ability to scale the scCO2 spray drying process from 4L to 10L chamber. The ratio of scCO2 and solution flow rate was kept constant. The products on both scales exhibited similar residual moisture contents, particle morphologies (SEM), and glass transition temperatures (DSC). After reconstitution, the lysozyme activity (enzymatic assay) and structure (circular dichroism, HP-SEC) were fully preserved, but the sub-visible particle content was slightly increased (flow imaging microscopy, nanoparticle tracking analysis). Furthermore, the drying condition was applicable to other proteins resulting in products of similar quality as the lysozyme formulations. In conclusion, we established scCO2 spray drying processing conditions for protein formulations without an organic solvent that holds promise for the industrial production of dry protein formulations. Copyright © 2014 Elsevier B.V. All rights reserved.

Preparation and In Vitro/Ex Vivo Evaluation of Moxifloxacin-Loaded PLGA Nanosuspensions for Ophthalmic Application

PubMed Central

Mudgil, Meetali; Pawar, Pravin K.

2013-01-01

The aim of the present investigation was to prepare a colloidal ophthalmic formulation to improve the residence time of moxifloxacin. Moxifloxacin-loaded poly(dl-lactide-co-glycolide) (PLGA) nanosuspensions were prepared by using the solvent evaporation technique. The nanosuspensions were characterised physically by using different techniques like particle size, zeta potential, FTIR, DSC, and XRD analysis. In vitro and ex vivo studies of nanosuspensions were carried out using a modified USP dissolution apparatus and all-glass Franz diffusion cells, respectively. The antibacterial activities of the nanosuspension and marketed formulations were performed against S. aureus and P. aeroginosa. The moxifloxacin-loaded PLGA nanosuspensions showed uniform particle size, ranging between 164–490 nm with negative zeta potential for all batches. The percentage entrapment efficiency of the drug-loaded nano-suspension was found to be between 84.09 to 92.05%. In vitro drug release studies suggest that all of the formulations showed extended drug release profiles and follow Korsemeyer-Peppas release kinetics. In vitro corneal permeability was found to be comparable with that of the marketed formulation across isolated goat cornea, indicating the suitability of the nanosuspension formulation in the ophthalmic delivery of moxifloxacin. The optimised nano-suspension was found to be more active against S. aureus and P. aeruginosa compared to the marketed eye drops. PMID:23833723

Mesoporous Nitrogen Doped Carbon-Glass Ceramic Cathode for High Performance Lithium-Oxygen Battery

DTIC Science & Technology

2012-06-01

dry room with controlled moisture content. Composite 3 films on nickel foam were used as working cathodes along with lithium metal as anode and the...cathode formulation [6,7,8,9,10], efficient oxygen reduction catalysts [11,12], electrolyte compositions [13,14], effect of moisture [15], etc...specimens. Structure and purity of these materials were performed by powder X-ray diffraction (XRD) on a Rigaku D/MAX-2250 diffractometer fitted with CuKα

Fundamentals of freeze-drying.

PubMed

Nail, Steven L; Jiang, Shan; Chongprasert, Suchart; Knopp, Shawn A

2002-01-01

Given the increasing importance of reducing development time for new pharmaceutical products, formulation and process development scientists must continually look for ways to "work smarter, not harder." Within the product development arena, this means reducing the amount of trial and error empiricism in arriving at a formulation and identification of processing conditions which will result in a quality final dosage form. Characterization of the freezing behavior of the intended formulation is necessary for developing processing conditions which will result in the shortest drying time while maintaining all critical quality attributes of the freeze-dried product. Analysis of frozen systems was discussed in detail, particularly with respect to the glass transition as the physical event underlying collapse during freeze-drying, eutectic mixture formation, and crystallization events upon warming of frozen systems. Experiments to determine how freezing and freeze-drying behavior is affected by changes in the composition of the formulation are often useful in establishing the "robustness" of a formulation. It is not uncommon for seemingly subtle changes in composition of the formulation, such as a change in formulation pH, buffer salt, drug concentration, or an additional excipient, to result in striking differences in freezing and freeze-drying behavior. With regard to selecting a formulation, it is wise to keep the formulation as simple as possible. If a buffer is needed, a minimum concentration should be used. The same principle applies to added salts: If used at all, the concentration should be kept to a minimum. For many proteins a combination of an amorphous excipient, such as a disaccharide, and a crystallizing excipient, such as glycine, will result in a suitable combination of chemical stability and physical stability of the freeze-dried solid. Concepts of heat and mass transfer are valuable in rational design of processing conditions. Heat transfer by conduction--the dominant mechanism of heat transfer in freeze-drying--is inefficient at the pressures used in freeze-drying. Steps should be taken to improve the thermal contact between the product and the shelf of the freeze dryer, such as eliminating metal trays from the drying process. Quantitation of the heat transfer coefficient for the geometry used is a useful way of assessing the impact of changes in the system such as elimination of product trays and changes in the vial. Because heat transfer by conduction through the vapor increases with increasing pressure, the commonly held point of view that "the lower the pressure, the better" is not true with respect to process efficiency. The optimum pressure for a given product is a function of the temperature at which freeze-drying is carried out, and lower pressures are needed at low product temperatures. The controlling resistance to mass transfer is almost always the resistance of the partially dried solids above the submination interface. This resistance can be minimized by avoiding fill volumes of more than about half the volume of the container. The development scientist should also recognize that very high concentrations of solute may not be appropriate for optimum freeze-drying, particularly if the resistance of the dried product layer increases sharply with concentration. Although the last 10 years has seen the publication of a significant body of literature of great value in allowing development scientists and engineers to "work smarter," there is still much work needed in both the science and the technology of freeze-drying. Scientific development is needed for improving analytical methodology for characterization of frozen systems and freeze-dried solids. A better understanding of the relationship between molecular mobility and reactivity is needed to allow accurate prediction of product stability at the intended storage temperature based on accelerated stability at higher temperatures. This requires that the temperature dependence of glass transition-associated mobility, particularly at temperatures below the glass transition, be studied in greater depth. The relevance of the concept of strong and fragile glasses to frozen systems and freeze-dried solids has only begun to be explored. The list of pharmaceutically acceptable protective solutes is very short, and more imagination--and work--is needed in order to develop pharmaceutically acceptable alternative stabilizers. There is a need for technology development in process monitoring, particularly in developing a way to measure the status of the product during freezing and freeze-drying without placing temperature measurement probes in individual vials of product. The current practice of placing thermocouples in vials is uncertain with respect to reliability of the data, inconsistent with elimination of personnel in close proximity to open vials of product in an aseptic environment, and incompatible with technology for automatic material handling in freeze-drying. In addition, a method for controlling the degree of supercooling during freezing would allow better control of freezing rate and would, in many cases, result in more consistent product quality.

Multiple Glass Transitions and Freezing Events of Aqueous Citric Acid

PubMed Central

2014-01-01

Calorimetric and optical cryo-microscope measurements of 10–64 wt % citric acid (CA) solutions subjected to moderate (3 K/min) and slow (0.5 and 0.1 K/min) cooling/warming rates and also to quenching/moderate warming between 320 and 133 K are presented. Depending on solution concentration and cooling rate, the obtained thermograms show one freezing event and from one to three liquid–glass transitions upon cooling and from one to six liquid–glass and reverse glass–liquid transitions, one or two freezing events, and one melting event upon warming of frozen/glassy CA/H2O. The multiple freezing events and glass transitions pertain to the mother CA/H2O solution itself and two freeze-concentrated solution regions, FCS1 and FCS2, of different concentrations. The FCS1 and FCS2 (or FCS22) are formed during the freezing of CA/H2O upon cooling and/or during the freezing upon warming of partly glassy or entirely glassy mother CA/H2O. The formation of two FCS1 and FCS22 regions during the freezing upon warming to our best knowledge has never been reported before. Using an optical cryo-microscope, we are able to observe the formation of a continuous ice framework (IF) and its morphology and reciprocal distribution of IF/(FCS1 + FCS2). Our results provide a new look at the freezing and glass transition behavior of aqueous solutions and can be used for the optimization of lyophilization and freezing of foods and biopharmaceutical formulations, among many other applications where freezing plays a crucial role. PMID:25482069

Oligosaccharide-based Surfactant/Citric Acid Buffer System Stabilizes Lactate Dehydrogenase during Freeze-drying and Storage without the Addition of Natural Sugar.

PubMed

Ogawa, Shigesaburo; Kawai, Ryuichiro; Koga, Maito; Asakura, Kouichi; Takahashi, Isao; Osanai, Shuichi

2016-06-01

Experiments were conducted to assess the maintenance effects of oligosaccharide-based surfactants on the enzymatic activity of a model protein, lactate dehydrogenase (LDH), during freeze-drying and room temperature storage using the citric acid buffer system. Oligosaccharide-based surfactants, which exhibit a high glass transition temperature (Tg), promoted the eminent retention of enzymatic activity during these protocols, whereas monosaccharide-based surfactants with a low Tg displayed poor performance at high concentration, albeit much better than that of Tween 80 at middle concentration. The increase in the alkyl chain length did not exert positive effects as observed for the maintenance effect during freeze-thawing, but an amphiphilic nature and a glass forming ability were crucial for the effective stabilization at a low excipient concentration during freeze-drying. Even a low oligosaccharide-based surfactant content (0.1 mg mL(-1)) could maintain LDH activity during freeze-drying, but a high surfactant content (1.0 mg mL(-1)) was required to prevent buffer precipitation and retain high LDH activity on storage. Regarding storage, glass formation restricted molecular mobility in the lyophilized matrix, and LDH activity was effectively retained. The present results describe a strategy based on the glass-forming ability of surfactant-type excipients that affords a natural sugar-free formulation or an alternative use for polysorbate-type surfactants.

A circumzenithal arc to study optics concepts with geometrical optics

NASA Astrophysics Data System (ADS)

Isik, Hakan

2017-05-01

This paper describes the formation of a circumzenithal arc for the purpose of teaching light and optics. A circumzenithal arc, an optic formation rarely witnessed by people, is formed in this study using a water-filled cylindrical glass illuminated by sunlight. Sunlight refracted at the top and side surfaces of the glass of water is dispersed into its constituent colours. First, multi-colour arcs are observed on paper at the bottom of the glass. Then, a single arc for each colour is observed on the floor when the rays are allowed to propagate to the furthest points from the glass. The change in observations is explained by formulating an equation for the geometry of the situation. The formula relates each point on the first refracting surface for an incoming light ray to a point further from the second refracting surface. Then, a parallel graph is drawn to visualize the superposition of colours to the formation of a single arc. The geometrical optics studies in this paper exemplify the concept of Snell’s law, total internal reflection and dispersion. The duration of the observation on a circumzenithal arc is limited by the altitude of the Sun in the sky. This study depends on the use of astronomy software to track solar altitude. Pedagogical aspects of the study are discussed for inquiry-based teaching and learning of light and optics concepts.

Understanding the structural drivers governing glass-water interactions in borosilicate based model bioactive glasses.

PubMed

Stone-Weiss, Nicholas; Pierce, Eric M; Youngman, Randall E; Gulbiten, Ozgur; Smith, Nicholas J; Du, Jincheng; Goel, Ashutosh

2018-01-01

The past decade has witnessed a significant upsurge in the development of borate and borosilicate based resorbable bioactive glasses owing to their faster degradation rate in comparison to their silicate counterparts. However, due to our lack of understanding about the fundamental science governing the aqueous corrosion of these glasses, most of the borate/borosilicate based bioactive glasses reported in the literature have been designed by "trial-and-error" approach. With an ever-increasing demand for their application in treating a broad spectrum of non-skeletal health problems, it is becoming increasingly difficult to design advanced glass formulations using the same conventional approach. Therefore, a paradigm shift from the "trial-and-error" approach to "materials-by-design" approach is required to develop new-generations of bioactive glasses with controlled release of functional ions tailored for specific patients and disease states, whereby material functions and properties can be predicted from first principles. Realizing this goal, however, requires a thorough understanding of the complex sequence of reactions that control the dissolution kinetics of bioactive glasses and the structural drivers that govern them. While there is a considerable amount of literature published on chemical dissolution behavior and apatite-forming ability of potentially bioactive glasses, the majority of this literature has been produced on silicate glass chemistries using different experimental and measurement protocols. It follows that inter-comparison of different datasets reveals inconsistencies between experimental groups. There are also some major experimental challenges or choices that need to be carefully navigated to unearth the mechanisms governing the chemical degradation behavior and kinetics of boron-containing bioactive glasses, and to accurately determine the composition-structure-property relationships. In order to address these challenges, a simplified borosilicate based model melt-quenched bioactive glass system has been studied to depict the impact of thermal history on its molecular structure and dissolution behavior in water. It has been shown that the methodology of quenching of the glass melt impacts the dissolution rate of the studied glasses by 1.5×-3× depending on the changes induced in their molecular structure due to variation in thermal history. Further, a recommendation has been made to study dissolution behavior of bioactive glasses using surface area of the sample - to - volume of solution (SA/V) approach instead of the currently followed mass of sample - to - volume of solution approach. The structural and chemical dissolution data obtained from bioactive glasses following the approach presented in this paper can be used to develop the structural descriptors and potential energy functions over a broad range of bioactive glass compositions. Realizing the goal of designing third generation bioactive glasses requires a thorough understanding of the complex sequence of reactions that control their rate of degradation (in physiological fluids) and the structural drivers that control them. In this article, we have highlighted some major experimental challenges and choices that need to be carefully navigated in order to unearth the mechanisms governing the chemical dissolution behavior of borosilicate based bioactive glasses. The proposed experimental approach allows us to gain a new level of conceptual understanding about the composition-structure-property relationships in these glass systems, which can be applied to attain a significant leap in designing borosilicate based bioactive glasses with controlled dissolution rates tailored for specific patient and disease states. Copyright © 2017 Acta Materialia Inc. All rights reserved.

Results For The Fourth Quarter 2014 Tank 50 WAC Slurry Sample: Chemical And Radionuclide Contaminants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crawford, C.

2015-09-30

This report details the chemical and radionuclide contaminant results for the characterization of the Calendar Year (CY) 2014 Fourth Quarter sampling of Tank 50 for the Saltstone Waste Acceptance Criteria (WAC) in effect at that time. Information from this characterization will be used by DWPF & Saltstone Facility Engineering (DSFE) to support the transfer of low-level aqueous waste from Tank 50 to the Salt Feed Tank in the Saltstone Facility in Z-Area, where the waste will be immobilized. This information is also used to update the Tank 50 Waste Characterization System.

Rheological Characterization of Unusual DWPF Slurry Samples (U)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koopman, D. C.

2005-09-01

A study was undertaken to identify and clarify examples of unusual rheological behavior in Defense Waste Processing Facility (DWPF) simulant slurry samples. Identification was accomplished by reviewing sludge, Sludge Receipt and Adjustment Tank (SRAT) product, and Slurry Mix Evaporator (SME) product simulant rheological results from the prior year. Clarification of unusual rheological behavior was achieved by developing and implementing new measurement techniques. Development of these new methods is covered in a separate report, WSRC-TR-2004-00334. This report includes a review of recent literature on unusual rheological behavior, followed by a summary of the rheological measurement results obtained on a set ofmore » unusual simulant samples. Shifts in rheological behavior of slurries as the wt. % total solids changed have been observed in numerous systems. The main finding of the experimental work was that the various unusual DWPF simulant slurry samples exhibit some degree of time dependent behavior. When a given shear rate is applied to a sample, the apparent viscosity of the slurry changes with time rather than remaining constant. These unusual simulant samples are more rheologically complex than Newtonian liquids or more simple slurries, neither of which shows significant time dependence. The study concludes that the unusual rheological behavior that has been observed is being caused by time dependent rheological properties in the slurries being measured. Most of the changes are due to the effect of time under shear, but SB3 SME products were also changing properties while stored in sample bottles. The most likely source of this shear-related time dependence for sludge is in the simulant preparation. More than a single source of time dependence was inferred for the simulant SME product slurries based on the range of phenomena observed. Rheological property changes were observed on the time-scale of a single measurement (minutes) as well as on a time scale of hours to weeks. The unusual shape of the slurry flow curves was not an artifact of the rheometric measurement. Adjusting the user-specified parameters in the rheometer measurement jobs can alter the shape of the flow curve of these time dependent samples, but this was not causing the unusual behavior. Variations in the measurement parameters caused the time dependence of a given slurry to manifest at different rates. The premise of the controlled shear rate flow curve measurement is that the dynamic response of the sample to a change in shear rate is nearly instantaneous. When this is the case, the data can be fitted to a time independent rheological equation, such as the Bingham plastic model. In those cases where this does not happen, interpretation of the data is difficult. Fitting time dependent data to time independent rheological equations, such as the Bingham plastic model, is also not appropriate.« less

LITERATURE REVIEW ON IMPACT OF GLYCOLATE ON THE 2H EVAPORATOR AND THE EFFLUENT TREATMENT FACILITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adu-Wusu, K.

2012-05-10

Glycolic acid (GA) is being studied as an alternate reductant in the Defense Waste Processing Facility (DWPF) feed preparation process. It will either be a total or partial replacement for the formic acid that is currently used. A literature review has been conducted on the impact of glycolate on two post-DWPF downstream systems - the 2H Evaporator system and the Effluent Treatment Facility (ETF). The DWPF recycle stream serves as a portion of the feed to the 2H Evaporator. Glycolate enters the evaporator system from the glycolate in the recycle stream. The overhead (i.e., condensed phase) from the 2H Evaporatormore » serves as a portion of the feed to the ETF. The literature search revealed that virtually no impact is anticipated for the 2H Evaporator. Glycolate may help reduce scale formation in the evaporator due to its high complexing ability. The drawback of the solubilizing ability is the potential impact on the criticality analysis of the 2H Evaporator system. It is recommended that at least a theoretical evaluation to confirm the finding that no self-propagating violent reactions with nitrate/nitrites will occur should be performed. Similarly, identification of sources of ignition relevant to glycolate and/or update of the composite flammability analysis to reflect the effects from the glycolate additions for the 2H Evaporator system are in order. An evaluation of the 2H Evaporator criticality analysis is also needed. A determination of the amount or fraction of the glycolate in the evaporator overhead is critical to more accurately assess its impact on the ETF. Hence, use of predictive models like OLI Environmental Simulation Package Software (OLI/ESP) and/or testing are recommended for the determination of the glycolate concentration in the overhead. The impact on the ETF depends on the concentration of glycolate in the ETF feed. The impact is classified as minor for feed glycolate concentrations {le} 33 mg/L or 0.44 mM. The ETF unit operations that will have minor/major impacts are chlorination, pH adjustment, 1st mercury removal, organics removal, 2nd mercury removal, and ion exchange. For minor impacts, the general approach is to use historical process operations data/modeling software like OLI/ESP and/or monitoring/compiled process operations data to resolve any uncertainties with testing as a last resort. For major impacts (i.e., glycolate concentrations > 33 mg/L or 0.44 mM), testing is recommended. No impact is envisaged for the following ETF unit operations regardless of the glycolate concentration - filtration, reverse osmosis, ion exchange resin regeneration, and evaporation.« less

Bismaleimide resins for flame resistant honeycomb sandwich panels

NASA Technical Reports Server (NTRS)

Stenzenberger, H. D.

1978-01-01

Bismaleimide resins are prime candidates for nonflammable aircraft interior panels. Three resin types with different structures and processing characteristics were formulated. Resin M 751 was used to fabricate 100 kg of glass fabric prepregs which were used for the preparation of face sheets for honeycomb sandwich panels. Prepreg characteristics and curing cycles for laminate fabrication are provided. In order to advance beyond the current solvent resin technology for fibre and fabric impregnation, a hot melt solvent-less resin system was prepared and characterized. Preliminary tests were performed to develop a wet bonding process for the fabrication of advanced sandwich honeycomb panels by use of polybismaleimide glass fabric face sheets and polybismaleimide Nomex honeycomb core. B-stage material was used for both the core and the face sheet, providing flatwise tensile properties equivalent to those obtained by the state-of-the-art 3-step process which includes an epoxy adhesive resin.

Dynamics of a molecular glass former: Energy landscapes for diffusion in ortho-terphenyl

NASA Astrophysics Data System (ADS)

Niblett, S. P.; de Souza, V. K.; Stevenson, J. D.; Wales, D. J.

2016-07-01

Relaxation times and transport processes of many glass-forming supercooled liquids exhibit a super-Arrhenius temperature dependence. We examine this phenomenon by computer simulation of the Lewis-Wahnström model for ortho-terphenyl. We propose a microscopic definition for a single-molecule cage-breaking transition and show that, when correlation behaviour is taken into account, these rearrangements are sufficient to reproduce the correct translational diffusion constants over an intermediate temperature range in the supercooled regime. We show that super-Arrhenius behaviour can be attributed to increasing negative correlation in particle movement at lower temperatures and relate this to the cage-breaking description. Finally, we sample the potential energy landscape of the model and show that it displays hierarchical ordering. Substructures in the landscape, which may correspond to metabasins, have boundaries defined by cage-breaking transitions. The cage-breaking formulation provides a direct link between the potential energy landscape and macroscopic diffusion behaviour.

Hanford High-Level Waste Vitrification Program at the Pacific Northwest National Laboratory: technology development - annotated bibliography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Larson, D.E.

1996-09-01

This report provides a collection of annotated bibliographies for documents prepared under the Hanford High-Level Waste Vitrification (Plant) Program. The bibliographies are for documents from Fiscal Year 1983 through Fiscal Year 1995, and include work conducted at or under the direction of the Pacific Northwest National Laboratory. The bibliographies included focus on the technology developed over the specified time period for vitrifying Hanford pretreated high-level waste. The following subject areas are included: General Documentation; Program Documentation; High-Level Waste Characterization; Glass Formulation and Characterization; Feed Preparation; Radioactive Feed Preparation and Glass Properties Testing; Full-Scale Feed Preparation Testing; Equipment Materials Testing; Meltermore » Performance Assessment and Evaluations; Liquid-Fed Ceramic Melter; Cold Crucible Melter; Stirred Melter; High-Temperature Melter; Melter Off-Gas Treatment; Vitrification Waste Treatment; Process, Product Control and Modeling; Analytical; and Canister Closure, Decontamination, and Handling« less

Out-of-equilibrium dynamical mean-field equations for the perceptron model

NASA Astrophysics Data System (ADS)

Agoritsas, Elisabeth; Biroli, Giulio; Urbani, Pierfrancesco; Zamponi, Francesco

2018-02-01

Perceptrons are the building blocks of many theoretical approaches to a wide range of complex systems, ranging from neural networks and deep learning machines, to constraint satisfaction problems, glasses and ecosystems. Despite their applicability and importance, a detailed study of their Langevin dynamics has never been performed yet. Here we derive the mean-field dynamical equations that describe the continuous random perceptron in the thermodynamic limit, in a very general setting with arbitrary noise and friction kernels, not necessarily related by equilibrium relations. We derive the equations in two ways: via a dynamical cavity method, and via a path-integral approach in its supersymmetric formulation. The end point of both approaches is the reduction of the dynamics of the system to an effective stochastic process for a representative dynamical variable. Because the perceptron is formally very close to a system of interacting particles in a high dimensional space, the methods we develop here can be transferred to the study of liquid and glasses in high dimensions. Potentially interesting applications are thus the study of the glass transition in active matter, the study of the dynamics around the jamming transition, and the calculation of rheological properties in driven systems.

Vibration characteristics and optimization for panel elastically supported in mobile phone

NASA Astrophysics Data System (ADS)

Kaito, Y.; Honda, S.; Narita, Y.

2016-09-01

In recent years, usage of smartphones and tablet terminals have spread around the world. These devices using touchscreen as a user interface are currently mainstream. Also, in order to let information of input or output surely know to users, there are some types of equipment having vibrational function in touchscreen. Here, the material of touchscreen consists of glass and the glass panel is fixed to a mobile phone's body by adhesive tapes along the edge of the panel. However, due to the difficulty of design of vibration, it needs investigation with a vast number of manufacturing prototypes. Moreover, the vibration characteristic of panels is not enough regarding intensity and a tactile impression. Therefore, in this study, the authors consider the vibration characteristic of glass panel elastically fixed by adhesive tapes along edges. First, they show modeling of adhesive tapes along edges of panel by using translational and rotational springs. Second, they show formulating vibration characteristic by using an energy method. Third, they optimize spring constants of translational and rotational springs by using Genetic Algorithm(GA) from the obtained expression. Finally, they consider natural frequencies and eigenmodes which were acquired from experiments and simulations.

Stability of collapse lyophilized influenza vaccine formulations.

PubMed

Anamur, Cihad; Winter, Gerhard; Engert, Julia

2015-04-10

A clear limitation of many liquid vaccines is the obligatory cold-chain distribution system. Therefore, distribution of a dried vaccine formulation may be beneficial in terms of vaccine stability, handling and transport. Collapse freeze-drying is a process which utilizes fairly aggressive but at the same time economic lyophilization cycles where the formulation is dried above its glass transition temperature. In this study, we used collapse freeze-drying for a thermosensitive model influenza vaccine (Pandemrix(®)). The dried lyophilizates were further cryo-milled to engineer powder particles in the size range of approximately 20-80 μm which is applicable for epidermal powder immunization. Vaccine potency and stability were neither affected by high temperature input during collapse lyophilization nor over a storage period of six months. Furthermore, cryo-milled vaccine lyophilizates showed good storage stability of up to three months at high storage temperature (40 °C). This technique can provide a powerful tool for the worldwide distribution of vaccine and for new application technologies such as engineered powder immunization. Copyright © 2015 Elsevier B.V. All rights reserved.

Thermal Gradient Mid- and Far-Infrared Spectroscopy as Tools for Characterization of Protein Carbohydrate Lyophilizates.

PubMed

Mensink, M A; Šibík, J; Frijlink, H W; van der Voort Maarschalk, K; Hinrichs, W L J; Zeitler, J A

2017-10-02

Protein drugs play an important role in modern day medicine. Typically, these proteins are formulated as liquids requiring cold chain processing. To circumvent the cold chain and achieve better storage stability, these proteins can be dried in the presence of carbohydrates. We demonstrate that thermal gradient mid- and far-infrared spectroscopy (FTIR and THz-TDS, respectively) can provide useful information about solid-state protein carbohydrate formulations regarding mobility and intermolecular interactions. A model protein (BSA) was lyophilized in the presence of three carbohydrates with different size and protein stabilizing capacity. A gradual increase in mobility was observed with increasing temperature in formulations containing protein and/or larger carbohydrates (oligo- or polysaccharides), lacking a clear onset of fast mobility as was observed for smaller molecules. Furthermore, both techniques are able to identify the glass transition temperatures (T g ) of the samples. FTIR provides additional information as it can independently monitor changes in protein and carbohydrate bands at the T g . Lastly, THz-TDS confirms previous findings that protein-carbohydrate interactions decrease with increasing molecular weight of the carbohydrate, which results in decreased protein stabilization.

The "Biogenetic Law" in zoology: from Ernst Haeckel's formulation to current approaches.

PubMed

Olsson, Lennart; Levit, Georgy S; Hoßfeld, Uwe

2017-06-01

150 years ago, in 1866, Ernst Haeckel published a book in two volumes called "Generelle Morphologie der Organismen" (General Morphology of Organisms) in which he formulated his biogenetic law, famously stating that ontogeny recapitulates phylogeny. Here we describe Haeckel's original idea and follow its development in the thinking of two scientists inspired by Haeckel, Alexei Sewertzoff and Adolf Naef. Sewertzoff and Naef initially approached the problem of reformulating Haeckel's law in similar ways, and formulated comparable hypotheses at a purely descriptive level. But their theoretical viewpoints were crucially different. While Sewertzoff laid the foundations for a Darwinian evolutionary morphology and is regarded as a forerunner of the Modern Synthesis, Naef was one of the most important figures in 'idealistic morphology', usually seen as a type of anti-Darwinism. Both Naef and Sewertzoff aimed to revise Haeckel's biogenetic law and came to comparable conclusions at the empirical level. We end our review with a brief look at the present situation in which molecular data are used to test the "hour-glass model", which can be seen as a modern version of the biogenetic law.

Healing efficiency and dynamic mechanical properties of self-healing epoxy systems

NASA Astrophysics Data System (ADS)

Guadagno, Liberata; Raimondo, Marialuigia; Naddeo, Carlo; Longo, Pasquale; Mariconda, Annaluisa; Binder, Wolfgang H.

2014-03-01

Several systems to develop self-repairing epoxy resins have recently been formulated. In this paper the effect of matrix nature and curing cycle on the healing efficiency and dynamic mechanical properties of self-healing epoxy resins were investigated. We discuss several aspects by transferring self-healing systems from the laboratory scale to real applications in the aeronautic field, such as the possibility to choose systems with increased glass transition temperature, high storage modulus and high values in the healing functionality under real working conditions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walker, J.M.

The physical properties: mechanical, electrical, and thermal of a general purpose epoxy potting compound, filled with either glass microspheres, aluminum oxide or beta-eucryptite and catalyzed with either an aliphatic amine, a liquid aromatic amine eutectic blend, or a liquid anhydride are discussed. The properties of a CTBN modified epoxy are also included. Twelve formulation-cure cycle combinations were chosen for evaluation. The temperature dependent properties from -65/sup 0/ to 400/sup 0/F (-54/sup 0/ to 204/sup 0/C) for the 12 combinations are given.

Development of a novel dry powder inhalation formulation for the delivery of rivastigmine hydrogen tartrate.

PubMed

Simon, Alice; Amaro, Maria Inês; Cabral, Lucio Mendes; Healy, Anne Marie; de Sousa, Valeria Pereira

2016-03-30

The purpose of this study was to prepare engineered particles of rivastigmine hydrogen tartrate (RHT) and to characterize the physicochemical and aerodynamic properties, in comparison to a lactose carrier formulation (LCF). Microparticles were prepared from ethanol/water solutions containing RHT with and without the incorporation of L-leucine (Leu), using a spray dryer. Dry powder inhaler formulations prepared were characterized by scanning electron microscopy, powder X-ray diffraction, laser diffraction particle sizing, ATR-FTIR, differential scanning calorimetry, bulk and tapped density, dynamic vapour sorption and in vitro aerosol deposition behaviour using a next generation impactor. The smooth-surfaced spherical morphology of the spray dried microparticles was altered by adding Leu, resulting in particles becoming increasingly wrinkled with increasing Leu. Powders presented low densities. The glass transition temperature was sufficiently high (>90 °C) to suggest good stability at room temperature. As Leu content increased, spray dried powders presented lower residual solvent content, lower particle size, higher fine particle fraction (FPF<5 μm), and lower mass median aerodynamic diameter (MMAD). The LCF showed a lower FPF and higher MMAD, relative to the spray dried formulations containing more than 10% Leu. Spray dried RHT powders presented better aerodynamic properties, constituting a potential drug delivery system for oral inhalation. Copyright © 2016. Published by Elsevier B.V.

Pediatric oral solutions with propranolol hydrochloride for extemporaneous compounding: the formulation and stability study.

PubMed

Klovrzová, Sylva; Zahálka, Lukáš; Matysová, Ludmila; Horák, Petr; Sklubalová, Zdenka

2013-02-01

The aim of this study is to formulate an extemporaneous pediatric oral solution of propranolol hydrochloride (PRO) 2 mg/ml for the therapy of infantile haemangioma or hypertension in a target age group of 1 month to school children and to evaluate its stability. A citric acid solution and/or a citrate-phosphate buffer solution, respectively, were used as the vehicles to achieve pH value of about 3, optimal for the stability of PRO. In order to mask the bitter taste of PRO, simple syrup was used as the sweetener. All solutions were stored in tightly closed brown glass bottles at 5 ± 3 °C and/or 25 ± 3 °C, respectively. The validated HPLC method was used to evaluate the concentration of PRO and a preservative, sodium benzoate, at time intervals of 0-180 days. All preparations were stable at both storage temperatures with pH values in the range of 2.8-3.2. According to pharmacopoeial requirements, the efficacy of sodium benzoate 0.05 % w/v was proved (Ph.Eur., 5.1.3). The preparation formulated with the citrate-phosphate buffer, in our experience, had better palatability than that formulated with the citric acid solution. propranolol hydrochloride pediatric preparation extemporaneous preparation solution stability testing HPLC.

An investigation into the crystallization tendency/kinetics of amorphous active pharmaceutical ingredients: A case study with dipyridamole and cinnarizine.

PubMed

Baghel, Shrawan; Cathcart, Helen; Redington, Wynette; O'Reilly, Niall J

2016-07-01

Amorphous drug formulations have great potential to enhance solubility and thus bioavailability of BCS class II drugs. However, the higher free energy and molecular mobility of the amorphous form drive them towards the crystalline state which makes them unstable. Accurate determination of the crystallization tendency/kinetics is the key to the successful design and development of such systems. In this study, dipyridamole (DPM) and cinnarizine (CNZ) have been selected as model compounds. Thermodynamic fragility (mT) was measured from the heat capacity change at the glass transition temperature (Tg) whereas dynamic fragility (mD) was evaluated using methods based on extrapolation of configurational entropy to zero [Formula: see text] , and heating rate dependence of Tg [Formula: see text] . The mean relaxation time of amorphous drugs was calculated from the Vogel-Tammann-Fulcher (VTF) equation. Furthermore, the correlation between fragility and glass forming ability (GFA) of the model drugs has been established and the relevance of these parameters to crystallization of amorphous drugs is also assessed. Moreover, the crystallization kinetics of model drugs under isothermal conditions has been studied using Johnson-Mehl-Avrami (JMA) approach to determine the Avrami constant 'n' which provides an insight into the mechanism of crystallization. To further probe into the crystallization mechanism, the non-isothermal crystallization kinetics of model systems were also analysed by statistically fitting the crystallization data to 15 different kinetic models and the relevance of model-free kinetic approach has been established. The crystallization mechanism for DPM and CNZ at each extent of transformation has been predicted. The calculated fragility, glass forming ability (GFA) and crystallization kinetics are found to be in good correlation with the stability prediction of amorphous solid dispersions. Thus, this research work involves a multidisciplinary approach to establish fragility, GFA and crystallization kinetics as stability predictors for amorphous drug formulations. Copyright © 2016 Elsevier B.V. All rights reserved.

Preliminary Technology Maturation Plan for Immobilization of High-Level Waste in Glass Ceramics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vienna, John D.; Crum, Jarrod V.; Sevigny, Gary J.

2012-09-30

A technology maturation plan (TMP) was developed for immobilization of high-level waste (HLW) raffinate in a glass ceramics waste form using a cold-crucible induction melter (CCIM). The TMP was prepared by the following process: 1) define the reference process and boundaries of the technology being matured, 2) evaluate the technology elements and identify the critical technology elements (CTE), 3) identify the technology readiness level (TRL) of each of the CTE’s using the DOE G 413.3-4, 4) describe the development and demonstration activities required to advance the TRLs to 4 and 6 in order, and 5) prepare a preliminary plan tomore » conduct the development and demonstration. Results of the technology readiness assessment identified five CTE’s and found relatively low TRL’s for each of them: • Mixing, sampling, and analysis of waste slurry and melter feed: TRL-1 • Feeding, melting, and pouring: TRL-1 • Glass ceramic formulation: TRL-1 • Canister cooling and crystallization: TRL-1 • Canister decontamination: TRL-4 Although the TRL’s are low for most of these CTE’s (TRL-1), the effort required to advance them to higher values. The activities required to advance the TRL’s are listed below: • Complete this TMP • Perform a preliminary engineering study • Characterize, estimate, and simulate waste to be treated • Laboratory scale glass ceramic testing • Melter and off-gas testing with simulants • Test the mixing, sampling, and analyses • Canister testing • Decontamination system testing • Issue a requirements document • Issue a risk management document • Complete preliminary design • Integrated pilot testing • Issue a waste compliance plan A preliminary schedule and budget were developed to complete these activities as summarized in the following table (assuming 2012 dollars). TRL Budget Year MSA FMP GCF CCC CD Overall $M 2012 1 1 1 1 4 1 0.3 2013 2 2 1 1 4 1 1.3 2014 2 3 1 1 4 1 1.8 2015 2 3 2 2 4 2 2.6 2016 2 3 2 2 4 2 4.9 2017 2 3 3 2 4 2 9.8 2018 3 3 3 3 4 3 7.9 2019 3 3 3 3 4 3 5.1 2020 3 3 3 3 4 3 14.6 2021 3 3 3 3 4 3 7.3 2022 3 3 3 3 4 3 8.8 2023 4 4 4 4 4 4 9.1 2024 5 5 5 5 5 5 6.9 2025 6 6 6 6 6 6 6.9 CCC = canister cooling and crystallization; FMP = feeding, melting, and pouring; GCF = glass ceramic formulation; MSA = mixing, sampling, and analyses. This TMP is intended to guide the development of the glass ceramics waste form and process to the point where it is ready for industrialization.« less

PROCESSING ALTERNATIVES FOR DESTRUCTION OF TETRAPHENYLBORATE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, D; Thomas Peters, T; Samuel Fink, S

Two processes were chosen in the 1980's at the Savannah River Site (SRS) to decontaminate the soluble High Level Waste (HLW). The In Tank Precipitation (ITP) process (1,2) was developed at SRS for the removal of radioactive cesium and actinides from the soluble HLW. Sodium tetraphenylborate was added to the waste to precipitate cesium and monosodium titanate (MST) was added to adsorb actinides, primarily uranium and plutonium. Two products of this process were a low activity waste stream and a concentrated organic stream containing cesium tetraphenylborate and actinides adsorbed on monosodium titanate (MST). A copper catalyzed acid hydrolysis process wasmore » built to process (3, 4) the Tank 48H cesium tetraphenylborate waste in the SRS's Defense Waste Processing Facility (DWPF). Operation of the DWPF would have resulted in the production of benzene for incineration in SRS's Consolidated Incineration Facility. This process was abandoned together with the ITP process in 1998 due to high benzene in ITP caused by decomposition of excess sodium tetraphenylborate. Processing in ITP resulted in the production of approximately 1.0 million liters of HLW. SRS has chosen a solvent extraction process combined with adsorption of the actinides to decontaminate the soluble HLW stream (5). However, the waste in Tank 48H is incompatible with existing waste processing facilities. As a result, a processing facility is needed to disposition the HLW in Tank 48H. This paper will describe the process for searching for processing options by SRS task teams for the disposition of the waste in Tank 48H. In addition, attempts to develop a caustic hydrolysis process for in tank destruction of tetraphenylborate will be presented. Lastly, the development of both a caustic and acidic copper catalyzed peroxide oxidation process will be discussed.« less

Stability of extemporaneously compounded dexamethasone in glass and plastic bottles and plastic syringes.

PubMed

Ensom, Mary H H; Décarie, Diane

2014-07-01

Dexamethasone is widely used to treat rheumatic and endocrine disorders and chemotherapy-induced nausea and vomiting. A palatable, alcohol-free liquid formulation, with a suitable concentration to allow reasonable administration volume, is available only via extemporaneous compounding. To evaluate the stability of dexamethasone suspensions in commercially available vehicles (Oral Mix and Oral Mix SF) in various types of containers after storage at 25°C and 4°C for up to 91 days. Dexamethasone suspensions (1 mg/mL) were prepared in Oral Mix and Oral Mix SF and then transferred to amber glass and plastic prescription bottles and plastic oral syringes. Suspensions in all 3 types of containers were stored at 25°C; suspensions in glass and plastic bottles were also stored at 4°C. Samples were collected weekly from each container up to 28 days and then every 2 weeks up to 91 days. The samples were analyzed by a validated, stability-indicating high-performance liquid chromatography - ultraviolet detection method. A suspension was considered stable if it maintained at least 90% of its initial dexamethasone concentration. Changes in colour, taste, odour, precipitation (and ease of resuspension), and pH were used to assess physical compatibility. All suspensions maintained at least 96% of the original concentration for up to 91 days with storage at 25°C or at 4°C. No notable changes in colour, taste, odour, precipitation, or pH were observed over the 91-day period. Dexamethasone suspensions (1 mg/mL) in Oral Mix and Oral Mix SF, stored in amber glass or plastic bottles or plastic syringes at 25°C or in amber glass or plastic bottles at 4°C can be expected to remain stable for up to 91 days.

Advanced development of non-discoloring EVA-based PV encapsulants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holley, W.H.; Galica, J.P.; Argo, S.C.

1996-01-01

The purpose of this investigation was to better define the problem of field yellowing of EVA-based PV encapsulant, through laboratory study of probable chemical mechanisms and the development of stabilization strategies for protecting EVA from discoloration. EVA from fielded modules was analyzed for vinyl acetate content, unsaturation, and additive levels. These test results were then compared to results from Xenon Arc Weather-Ometer aged glass/EVA/glass laminates made in the laboratory. Variables evaluated in Weather-Ometer aged laminates included ``standard-cure`` A9918P EVA, ``fast-cure`` 15295P EVA, low iron glass superstrate containing cerium oxide, and systematic elimination or addition of specific additives. Six significant findingsmore » were revealed: 1) Improved ``standard-cure`` and ``fast-cure`` type EVA encapsulants, formulations X9903P and X15303P, respectively, showed little or no yellowing after extended Weather-Ometer exposure; 2) The use of {open_quote}{open_quote}fast-cure{close_quote}{close_quote} EVA reduced discoloration when compared with {open_quote}{open_quote}standard-cure{close_quote}{close_quote} A9918P EVA; 3) Glass superstrate containing cerium oxide resulted in a reduced rate of EVA discoloration; 4) {open_quote}{open_quote}Fast-cure{close_quote}{close_quote} EVA used with glass superstrate containing cerium oxide showed no visible yellowing after 32 weeks in the Weather-Ometer{emdash}a period estimated to be roughly equivalent to 20{endash}30 years of exposure in the Southwest; 5) Severely discolored EVA samples from the field showed no measurable loss of acetate group and little detectable unsaturation; and 6) EVA encapsulant with a Tefzel cover exhibited no yellowing after extended Weather-Ometer exposure. {copyright} {ital 1996 American Institute of Physics.}« less

Mannitol/l-Arginine-Based Formulation Systems for Freeze Drying of Protein Pharmaceuticals: Effect of the l-Arginine Counter Ion and Formulation Composition on the Formulation Properties and the Physical State of Mannitol.

PubMed

Stärtzel, Peter; Gieseler, Henning; Gieseler, Margit; Abdul-Fattah, Ahmad M; Adler, Michael; Mahler, Hanns-Christian; Goldbach, Pierre

2016-10-01

Previous studies have shown that protein storage stability in freeze-dried l-arginine-based systems improved in the presence of chloride ions. However, chloride ions reduced the glass transition temperature of the freeze concentrate (Tg') and made freeze drying more challenging. In this study, l-arginine was freeze dried with mannitol to obtain partially crystalline solids that can be freeze dried in a fast process and result in elegant cakes. We characterized the effect of different l-arginine counter ions on physicochemical properties of mannitol compared with mannitol/sucrose systems. Thermal properties of formulations with different compositions were correlated to thermal history during freeze drying and to physicochemical properties (cake appearance, residual moisture, reconstitution time, crystallinity). Partially crystalline solids were obtained even at the highest l-arginine level (mannitol:l-arginine of 2:1) used in this study. All l-arginine-containing formulations yielded elegant cakes. Only cakes containing l-arginine chloride and succinate showed a surface "crust" formed by phase separation. X-ray powder diffraction showed that inhibition of mannitol crystallization was stronger for l-arginine compared with sucrose and varied with the type of l-arginine counter ion. The counter ion affected mannitol polymorphism and higher levels of mannitol hemi-hydrate were obtained at high levels of l-arginine chloride. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Final Report - Glass Formulation Testing to Increase Sulfate Volatilization from Melter, VSL-04R4970-1, Rev. 0, dated 2/24/05

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, Albert A.; Matlack, K. A.; Pegg, I. L.

2013-11-13

The principal objectives of the DM100 and DM10 tests were to determine the impact of four different organics and one inorganic feed additive on sulfate volatilization and to determine the sulfur partitioning between the glass and the off-gas system. The tests provided information on melter processing characteristics and off-gas data including sulfur incorporation and partitioning. A series of DM10 and DM100 melter tests were conducted using a LAW Envelope A feed. The testing was divided into three parts. The first part involved a series of DM10 melter tests with four different organic feed additives: sugar, polyethylene glycol (PEG), starch, andmore » urea. The second part involved two confirmatory 50-hour melter tests on the DM100 using the best combination of reductants and conditions based on the DM10 results. The third part was performed on the DM100 with feeds containing vanadium oxide (V{sub 2}O{sub 5}) as an inorganic additive to increase sulfur partitioning to the off-gas. Although vanadium oxide is not a reductant, previous testing has shown that vanadium shows promise for partitioning sulfur to the melter exhaust, presumably through its known catalytic effect on the SO{sub 2}/SO{sub 3} reaction. Crucible-scale tests were conducted prior to the melter tests to confirm that the glasses and feeds would be processable in the melter and that the glasses would meet the waste form (ILAW) performance requirements. Thus, the major objectives of these tests were to: Perform screening tests on the DM10 followed by tests on the DM100-WV system using a LAW -Envelope A feed with four organic additives to assess their impact on sulfur volatilization. Perform tests on the DM100-WV system using a LAW -Envelope A feed containing vanadium oxide to assess its impact on sulfur volatilization. Determine feed processability and product quality with the above additives. Collect melter emissions data to determine the effect of additives on sulfur partitioning and melter emissions. Collect and analyze discharged glass to determine sulfur retention in the glass. Prepare and characterize feeds and glasses with the additives to confirm that the feeds and the glass melts are suitable for processing in the DM100 melter. Prepare and characterize glasses with the additives to confirm that the glasses meet the waste form (ILAW) performance requirements.« less

Effects of N-vinylpyrrolidone (NVP) containing polyelectrolytes on surface properties of conventional glass-ionomer cements (GIC).

PubMed

Moshaverinia, Alireza; Roohpour, Nima; Ansari, Sahar; Moshaverinia, Maryam; Schricker, Scott; Darr, Jawwad A; Rehman, Ihtesham U

2009-10-01

It has been found that polyacids containing an N-vinylpyrrolidinone (NVP) comonomer produces a glass inomer cement with improved mechanical and handling properties. The objective of this study was to investigate the effect of NVP modified polyelectrolytes on the surface properties and shear bond strength to dentin of glass ionomer cements. Poly(acrylic acid (AA)-co-itaconic acid (IA)-co-N-vinylpyrrolidone) was synthesized by free radical polymerization. The terpolymer was characterized using (1)H NMR, FTIR spectroscopy and viscometry for solution properties. The synthesized polymers were used in glass ionomer cement formulations (Fuji II commercial GIC). Surface properties (wettability) of modified cements were studied by water contact angle measurements as a function of time. Work of adhesion values of different surfaces was also determined. The effect of NVP modified polyacid, on bond strength of glass-ionomer cement to dentin was also investigated. The mean data obtained from contact angle and bonding strength measurements were subjected to one- and two-way analysis of variance (ANOVA) at alpha=0.05. Results showed that NVP modified glass ionomer cements showed significantly lower contact angles (theta=47 degrees) and higher work of adhesion (WA=59.4 erg/cm(2)) in comparison to commercially available Fuji II GIC (theta=60 degrees and WA=50.3 erg/cm(2), respectively). The wettability of dentin surfaces conditioned with NVP containing terpolymer was higher (theta=21 degrees, WA=74.2 erg/cm(2)) than dentin conditioned with Fuji conditioner (theta=30 degrees, WA=69 erg/cm(2)). The experimental cement also showed higher but not statistically significant values for shear bond strength to dentin (7.8 MPa), when compared to control group (7.3 MPa). It was concluded that NVP containing polyelectrolytes are better dentin conditioners than the commercially available dentin conditioner (Fuji Cavity Conditioner, GC). NVP containing terpolymers can enhance the surface properties of GICs and also increase their bond strength to the dentin.

A novel parameter to describe the glass-forming ability of alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, E. S.; Ryu, C. W.; Kim, W. T.

2015-08-14

In this paper, we propose a new parameter for glass-forming ability (GFA) based on the combination of thermodynamic (stability of stable and metastable liquids by ΔT{sub m} = T{sub m}{sup mix} − T{sub l} and ΔT{sub x} = T{sub x} − T{sub g}, respectively) and kinetic (resistance to crystallization by T{sub x}) aspects for glass formation. The parameter is defined as ε = (ΔT{sub m} + ΔT{sub x} + T{sub x})/T{sub m}{sup mix} without directly adding T{sub g} while considering the whole temperature range for glass formation up to T{sub m}{sup mix}, which reflects the relative position of crystallization curve in continuous cooling transformation diagram. The relationship between the εmore » parameter and critical cooling rate (R{sub c}) or maximum section thickness for glass formation (Z{sub max}) clearly confirms that the ε parameter exhibits a better correlation with GFA than other commonly used GFA parameters, such as ΔT{sub x} (=T{sub x} − T{sub g}), K (=[T{sub x} − T{sub g}]/[T{sub l} − T{sub x}]), ΔT*(=(T{sub m}{sup mix} − T{sub l})/T{sub m}{sup mix}), T{sub rg} (=T{sub g}/T{sub l}), and γ (=[T{sub x}]/[T{sub l} + T{sub g}]). The relationship between the ε parameter and R{sub c} or Z{sub max} is also formulated and evaluated in the study. The results suggest that the ε parameter can effectively predict R{sub c} and Z{sub max} for various glass-forming alloys, which would permit more widespread uses of these paradigm-shifting materials in a variety of industries.« less

Deployment of Cesium Recovered from High Level Liquid Waste for Irradiation - Indian Scenario - 13128

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vincent, Tessy; Shah, J.G.; Kumar, Amar

2013-07-01

Recovery of Cs-137 from HLW and its utilisation as source pencil in place of Co-60 is vital for medical and sewage treatment applications in India. For separation of Cs, specific ion exchange resins as well as 'Calyx crown' solvent have been developed and synthesized indigenously. A flow sheet involving separation of Cs from acidic HLW using Ammonium Molybdo Phosphate (AMP) resins, recovery of Cs from the loaded AMP column by dissolving it in alkali, ion exchange purification of Cs rich alkaline solution using Resorcinol-Formaldehyde Poly condensate (RF) resins and its elution in cesium nitrate form was developed and demonstrated. Solventmore » extraction route employing 0.03 Molar, 1-3-octyl oxy Calyx (4) arene crown-6 in 30% isodecyl alcohol and dodecane was also established using mixer settlers. Cesium lithium borosilicate glass based formulations have been considered as a glass matrix for Cs irradiation pencils. While choosing this vitreous matrix, attributes addressing maximum possible Cs-137 loading, low glass pouring temperature to minimise Cs volatility, reasonably good mechanical strength and good chemical durability have been considered. Recovered cesium nitrate solution was vitrified along with glass additives in an induction heated metallic melter and subsequently poured into 12 numbers of Cs irradiation pencils positioned on turn-table equipped with the load cell. The complete cycle involving recovery of Cs from HLW followed by its conversion into Cs pencil was demonstrated. (authors)« less

Liquidus temperature in the spinel primary phase field: A comparison between optical and crystal fraction methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riley, Brian J.; Hrma, Pavel; Crum, Jarrod V.

Liquidus temperature (TL) was measured for simulated high-level waste borosilicate glasses covering a Hanford composition region, using an optical method and a crystal-fraction extrapolation method with X-ray diffraction data from isothermal heat treatments. The 38 glasses encompassed a one-component-at-a-time variation of a 16-component matrix. The TL values ranged from 1006°C to 1603°C. First-order polynomial models were fitted to data to obtain coefficients in terms of the effect of 1 mass% component addition on the TL: TL-increasing oxides Cr2O3 (264°C), “Others” (minor components, 163°C), oxides of noble metals (137°C), NiO (91°C), Al2O3 and Fe2O3 (~19–21°C); TL-decreasing oxides K2O (-26°C), Na2O (-41°C),more » and Li2O (-68°C); oxides of little effect MnO, P2O5, ZrO2, F, Bi2O3, SiO2, B2O3, and CaO (9 to -12°C). Also presented are temperatures (T1%) at which glasses contain 1 vol% of spinel as these values are considered relevant to the Hanford Tank Waste Treatment and Immobilization Plant. The measured and estimated values are compared and contrasted and the effect of TL and T1% on glass formulation is discussed.« less

Electrical conductivity and modulus formulation in zinc modified bismuth boro-tellurite glasses

NASA Astrophysics Data System (ADS)

Dhankhar, Sunil; Kundu, R. S.; Dult, Meenakshi; Murugavel, S.; Punia, R.; Kishore, N.

2016-09-01

The ac conductivity of zinc modified tellurium based quaternary glasses having composition 60 TeO2-10 B2O3-(30 - x) Bi2O3-x ZnO; x = 10, 15, 20, 25 and 30 has been investigated in the frequency range 10-1-105 Hz and in temperature range 483-593 K. Frequency and temperature dependent ac conductivity found to obey Jonscher power law modified by Almond-West. DC conductivity, crossover frequency and frequency exponent have been estimated from the fitting of the experimental data of conductivity with Jonscher power law modified by Almond-West. The ac conductivity and its frequency exponent have been analyzed by various theoretical models. In presently studied glasses ac conduction takes place via tunneling of overlapping large polaron tunneling. Activation energy is found to be increased with increase in zinc content and dc conduction takes place via variable range hopping proposed by Mott with some modification suggested by Punia et al. The value of the stretched exponent ( β) obtained by fitting of M^' ' }} reveals the presence of non-Debye type relaxation. Scaling spectra of ac conductivity and electric modulus collapse into a single master curve for all compositions and temperatures, reveals the presence of composition and temperature independent conduction and relaxation process in these glasses. Activation energy of conduction ( W) and electric modulus ( E R ) are nearly equal, indicating that polaron have to overcome the same energy barrier during conduction as well as relaxation processes.

Thermal mirror spectrometry: An experimental investigation of optical glasses

NASA Astrophysics Data System (ADS)

Zanuto, V. S.; Herculano, L. S.; Baesso, M. L.; Lukasievicz, G. V. B.; Jacinto, C.; Malacarne, L. C.; Astrath, N. G. C.

2013-03-01

The Thermal mirror technique relies on measuring laser-induced nanoscale surface deformation of a solid sample. The amplitude of the effect is directly dependent on the optical absorption and linear thermal expansion coefficients, and the time evolution depends on the heat diffusion properties of the sample. Measurement of transient signals provide direct access to thermal, optical and mechanical properties of the material. The theoretical models describing this effect can be formulated for very low optical absorbing and for absorbing materials. In addition, the theories describing the effect apply for semi-infinite and finite samples. In this work, we apply the Thermal mirror technique to measure physical properties of optical glasses. The semi-infinite and finite models are used to investigate very low optical absorbing glasses. The thickness limit for which the semi-infinite model retrieves the correct values of the thermal diffusivity and amplitude of the transient is obtained using the finite description. This procedure is also employed on absorbing glasses, and the semi-infinite Beer-Lambert law model is used to analyze the experimental data. The experimental data show the need to use the finite model for samples with very low bulk absorption coefficients and thicknesses L < 1.5 mm. This analysis helped to establish limit values of thickness for which the semi-infinite model for absorbing materials could be used, L > 1.0 mm in this case. In addition, the physical properties of the samples were calculated and absolute values derived.

Field Testing of Thermoplastic Encapsulants in High-Temperature Installations

DOE PAGES

Kempe, Michael D.; Miller, David C.; Wohlgemuth, John H.; ...

2015-11-01

Recently there has been increased interest in using thermoplastic encapsulant materials in photovoltaic modules, but concerns have been raised about whether these would be mechanically stable at high temperatures in the field. This has become a significant topic of discussion in the development of IEC 61730 and IEC 61215. We constructed eight pairs of crystalline-silicon modules and eight pairs of glass/encapsulation/glass thin-film mock modules using different encapsulant materials, of which only two were formulated to chemically crosslink. One module set was exposed outdoors with thermal insulation on the back side in Mesa, Arizona, in the summer (hot-dry), and an identicalmore » module set was exposed in environmental chambers. High-precision creep measurements (±20 μm) and electrical performance measurements indicate that despite many of these polymeric materials operating in the melt or rubbery state during outdoor deployment, no significant creep was seen because of their high viscosity, lower operating temperature at the edges, and/or the formation of chemical crosslinks in many of the encapsulants with age despite the absence of a crosslinking agent. Only an ethylene-vinyl acetate (EVA) encapsulant formulated without a peroxide crosslinking agent crept significantly. When the crystalline-silicon modules, the physical restraint of the backsheet reduced creep further and was not detectable even for the EVA without peroxide. Because of the propensity of some polymeric materials to crosslink as they age, typical thermoplastic encapsulants would be unlikely to result in creep in the vast majority of installations.« less

Extended electron energy loss fine structure simulation of the local boron environment in sodium aluminoborosilicate glasses containing gadolinium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qian, Morris; Li, Hong; Li, Liyu

Gadolinium can be dissolved in sodium-alumino-borosilicate glasses up to 47 wt% in a baseline borosilicate glass (mol%) 20 B2O3, 5 Al2O3, 60 SiO2,and 20 Na2O. Understanding of Gd dissolution in borosilicate melts is important in glass formulation optimization. Electron energy loss fine structure (ELFS) spectroscopy is chosen, which provides well resolved local atomic structure information for both amorphous and crystalline materials with high sensitivity to low Z elements such as Al, B, Na, O, and Si where the x-ray absorption fine structure (XAFS) technique faces experimental difficulty. In this study, we report our results of boron K-edge ELFS study. Twomore » borosilicate glass samples with 30 and 47 mass% Gd2O3, B20Gd30 and B20Gd47were chosen for B K-edge ELFS study. EEL spectra were acquired on a Philips 430 TEM equipped with Gatan PEELS system 666 and EL/P 2.1 software with Custom function AcqLong. The ELFS data analysis was performed using UWELFS, UWXAFS and FEFF software. From our Gd solubility study, the local structure of Gd in the borate environment possibly resembles double chain structure found in crystalline Gd(BO2)3 as proposed by Chakraborty et al. The B/Gd ratio's in both glasses are smaller then 3, which means the excess Gd atoms in the Si-sites would be 17 and 60 mol% of the total Gd atoms, respectively according to the model, yet the local environment of borate sites saturated with Gd should be remained. To verity above hypothesis, the double chain structure model was applied to fit boron K-edge. The model was shown to well fit experimental boron K-edge EELS spectra for both glasses with some degree of distance distortion which is understandable in amorphous structure. Therefore, it is very likely that Gd stabilized in borate sites has a local structure resembling the double chain Gd(BO2)3 structure as proposed by our solubility study and literature.« less

Controlling the Release of Indomethacin from Glass Solutions Layered with a Rate Controlling Membrane Using Fluid-Bed Processing. Part 1: Surface and Cross-Sectional Chemical Analysis.

PubMed

Dereymaker, Aswin; Scurr, David J; Steer, Elisabeth D; Roberts, Clive J; Van den Mooter, Guy

2017-04-03

Fluid bed coating has been shown to be a suitable manufacturing technique to formulate poorly soluble drugs in glass solutions. Layering inert carriers with a drug-polymer mixture enables these beads to be immediately filled into capsules, thus avoiding additional, potentially destabilizing, downstream processing. In this study, fluid bed coating is proposed for the production of controlled release dosage forms of glass solutions by applying a second, rate controlling membrane on top of the glass solution. Adding a second coating layer adds to the physical and chemical complexity of the drug delivery system, so a thorough understanding of the physical structure and phase behavior of the different coating layers is needed. This study aimed to investigate the surface and cross-sectional characteristics (employing scanning electron microscopy (SEM) and time of flight secondary ion mass spectrometry (ToF-SIMS)) of an indomethacin-polyvinylpyrrolidone (PVP) glass solution, top-coated with a release rate controlling membrane consisting of either ethyl cellulose or Eudragit RL. The implications of the addition of a pore former (PVP) and the coating medium (ethanol or water) were also considered. In addition, polymer miscibility and the phase analysis of the underlying glass solution were investigated. Significant differences in surface and cross-sectional topography of the different rate controlling membranes or the way they are applied (solution vs dispersion) were observed. These observations can be linked to the polymer miscibility differences. The presence of PVP was observed in all rate controlling membranes, even if it is not part of the coating solution. This could be attributed to residual powder presence in the coating chamber. The distribution of PVP among the sample surfaces depends on the concentration and the rate controlling polymer used. Differences can again be linked to polymer miscibility. Finally, it was shown that the underlying glass solution layer remains amorphous after coating of the rate controlling membrane, whether formed from an ethanol solution or an aqueous dispersion.

SOLIDIFICATION OF THE HANFORD LAW WASTE STREAM PRODUCED AS A RESULT OF NEAR-TANK CONTINUOUS SLUDGE LEACHING AND SODIUM HYDROXIDE RECOVERY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reigel, M.; Johnson, F.; Crawford, C.

2011-09-20

The U.S. Department of Energy (DOE), Office of River Protection (ORP), is responsible for the remediation and stabilization of the Hanford Site tank farms, including 53 million gallons of highly radioactive mixed wasted waste contained in 177 underground tanks. The plan calls for all waste retrieved from the tanks to be transferred to the Waste Treatment Plant (WTP). The WTP will consist of three primary facilities including pretreatment facilities for Low Activity Waste (LAW) to remove aluminum, chromium and other solids and radioisotopes that are undesirable in the High Level Waste (HLW) stream. Removal of aluminum from HLW sludge canmore » be accomplished through continuous sludge leaching of the aluminum from the HLW sludge as sodium aluminate; however, this process will introduce a significant amount of sodium hydroxide into the waste stream and consequently will increase the volume of waste to be dispositioned. A sodium recovery process is needed to remove the sodium hydroxide and recycle it back to the aluminum dissolution process. The resulting LAW waste stream has a high concentration of aluminum and sodium and will require alternative immobilization methods. Five waste forms were evaluated for immobilization of LAW at Hanford after the sodium recovery process. The waste forms considered for these two waste streams include low temperature processes (Saltstone/Cast stone and geopolymers), intermediate temperature processes (steam reforming and phosphate glasses) and high temperature processes (vitrification). These immobilization methods and the waste forms produced were evaluated for (1) compliance with the Performance Assessment (PA) requirements for disposal at the IDF, (2) waste form volume (waste loading), and (3) compatibility with the tank farms and systems. The iron phosphate glasses tested using the product consistency test had normalized release rates lower than the waste form requirements although the CCC glasses had higher release rates than the quenched glasses. However, the waste form failed to meet the vapor hydration test criteria listed in the WTP contract. In addition, the waste loading in the phosphate glasses were not as high as other candidate waste forms. Vitrification of HLW waste as borosilicate glass is a proven process; however the HLW and LAW streams at Hanford can vary significantly from waste currently being immobilized. The ccc glasses show lower release rates for B and Na than the quenched glasses and all glasses meet the acceptance criterion of < 4 g/L. Glass samples spiked with Re{sub 2}O{sub 7} also passed the PCT test. However, further vapor hydration testing must be performed since all the samples cracked and the test could not be performed. The waste loading of the iron phosphate and borosilicate glasses are approximately 20 and 25% respectively. The steam reforming process produced the predicted waste form for both the high and low aluminate waste streams. The predicted waste loadings for the monolithic samples is approximately 39%, which is higher than the glass waste forms; however, at the time of this report, no monolithic samples were made and therefore compliance with the PA cannot be determined. The waste loading in the geopolymer is approximately 40% but can vary with the sodium hydroxide content in the waste stream. Initial geopolymer mixes revealed compressive strengths that are greater than 500 psi for the low aluminate mixes and less than 500 psi for the high aluminate mixes. Further work testing needs to be performed to formulate a geopolymer waste form made using a high aluminate salt solution. A cementitious waste form has the advantage that the process is performed at ambient conditions and is a proven process currently in use for LAW disposal. The Saltstone/Cast Stone formulated using low and high aluminate salt solutions retained at least 97% of the Re that was added to the mix as a dopant. While this data is promising, additional leaching testing must be performed to show compliance with the PA. Compressive strength tests must also be performed on the Cast Stone monoliths to verify PA compliance. Based on testing performed for this report, the borosilicate glass and Cast Stone are the recommended waste forms for further testing. Both are proven technologies for radioactive waste disposal and the initial testing using simulated Hanford LAW waste shows compliance with the PA. Both are resistant to leaching and have greater than 25% waste loading.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pern, F.J.; Glick, S.H.; Czanderna, A.W.

The stabilization effects of various superstrate materials against UV-induced EVA discoloration and the effect of photocurrent enhancement by white light-reflecting substrates are summarized. Based on the results, some alternative PV module encapsulation schemes are proposed for improved module performance, where the current or modified formulations of EVA encapsulants still can be used so that the typical processing tools and conditions need not to be changed significantly. The schemes are designed in an attempt to eliminate or minimize the EVA yellow-browning and to increase the module power output. Four key experimental results from the studies of EVA discoloration and encapsulation aremore » to employ: (1) UV-absorbing (filtering) glasses as superstrates to protect EVA from UV-induced discoloration, (2) gas-permeable polymer films as superstrates and/or substrates to prevent EVA yellowing by permitting photobleaching reactions, (3) modified EVA formulations, and (4) internal reflection of the light by white substrates. {copyright} {ital 1996 American Institute of Physics.}« less

Nuclear quadrupole resonance lineshape analysis for different motional models: Stochastic Liouville approach

NASA Astrophysics Data System (ADS)

Kruk, D.; Earle, K. A.; Mielczarek, A.; Kubica, A.; Milewska, A.; Moscicki, J.

2011-12-01

A general theory of lineshapes in nuclear quadrupole resonance (NQR), based on the stochastic Liouville equation, is presented. The description is valid for arbitrary motional conditions (particularly beyond the valid range of perturbation approaches) and interaction strengths. It can be applied to the computation of NQR spectra for any spin quantum number and for any applied magnetic field. The treatment presented here is an adaptation of the "Swedish slow motion theory," [T. Nilsson and J. Kowalewski, J. Magn. Reson. 146, 345 (2000), 10.1006/jmre.2000.2125] originally formulated for paramagnetic systems, to NQR spectral analysis. The description is formulated for simple (Brownian) diffusion, free diffusion, and jump diffusion models. The two latter models account for molecular cooperativity effects in dense systems (such as liquids of high viscosity or molecular glasses). The sensitivity of NQR slow motion spectra to the mechanism of the motional processes modulating the nuclear quadrupole interaction is discussed.

Solvent-free melting techniques for the preparation of lipid-based solid oral formulations.

PubMed

Becker, Karin; Salar-Behzadi, Sharareh; Zimmer, Andreas

2015-05-01

Lipid excipients are applied for numerous purposes such as taste masking, controlled release, improvement of swallowability and moisture protection. Several melting techniques have evolved in the last decades. Common examples are melt coating, melt granulation and melt extrusion. The required equipment ranges from ordinary glass beakers for lab scale up to large machines such as fluid bed coaters, spray dryers or extruders. This allows for upscaling to pilot or production scale. Solvent free melt processing provides a cost-effective, time-saving and eco-friendly method for the food and pharmaceutical industries. This review intends to give a critical overview of the published literature on experiences, formulations and challenges and to show possibilities for future developments in this promising field. Moreover, it should serve as a guide for selecting the best excipients and manufacturing techniques for the development of a product with specific properties using solvent free melt processing.

Extemporaneous Compounding of Oral Acitretin Suspension for Pediatric Patient with Generalized Pustular Psoriasis.

PubMed

Choo, Winnie

2016-01-01

Generalized pustular psoriasis is rare in children, but it can occur and affect an extensive body surface area of a child. Treatment regimens can include medications that are not available in pediatric dosage form. Acitretin is considered one of the treatment options for acute generalized pustular psoriasis in children, but, in Singapore, it is only available as Neotigason capsules. Extemporaneous compounding of the powder content in the capsules was developed for formulating the oral acitretin suspension with a standardized formulation table and compounding process at National Skin Centre. An appropriate beyond-use date of the extemporaneous preparation was assigned after reviewing the photostability data of acitretin, compatibility of the active ingredient and excipients, and United States Pharmacopeia <795> guidelines. It is deemed appropriate to assign a beyond-use date of 14 days when the extemporaneous preparation is stored in amber glass bottles at 2 degrees C to 8 degrees C.

Dry-powder formulations of non-covalent protein complexes with linear or miktoarm copolymers for pulmonary delivery.

PubMed

Nieto-Orellana, Alejandro; Coghlan, David; Rothery, Malcolm; Falcone, Franco H; Bosquillon, Cynthia; Childerhouse, Nick; Mantovani, Giuseppe; Stolnik, Snow

2018-04-05

Pulmonary delivery of protein therapeutics has considerable clinical potential for treating both local and systemic diseases. However, poor protein conformational stability, immunogenicity and protein degradation by proteolytic enzymes in the lung are major challenges to overcome for the development of effective therapeutics. To address these, a family of structurally related copolymers comprising polyethylene glycol, mPEG 2k , and poly(glutamic acid) with linear A-B (mPEG 2k -lin-GA) and miktoarm A-B 3 (mPEG 2k -mik-(GA) 3 ) macromolecular architectures was investigated as potential protein stabilisers. These copolymers form non-covalent nanocomplexes with a model protein (lysozyme) which can be formulated into dry powders by spray-drying using common aerosol excipients (mannitol, trehalose and leucine). Powder formulations with excellent aerodynamic properties (fine particle fraction of up to 68%) were obtained with particle size (D 50 ) in the 2.5 µm range, low moisture content (<5%), and high glass transitions temperatures, i.e. formulation attributes all suitable for inhalation application. In aqueous medium, dry powders rapidly disintegrated into the original polymer-protein nanocomplexes which provided protection towards proteolytic degradation. Taken together, the present study shows that dry powders based on (mPEG 2k -polyGA)-protein nanocomplexes possess potentials as an inhalation delivery system. Copyright © 2018 Elsevier B.V. All rights reserved.

Parenteral formulation of an antileishmanial drug candidate--tackling poor solubility, chemical instability, and polymorphism.

PubMed

Kupetz, Eva; Preu, Lutz; Kunick, Conrad; Bunjes, Heike

2013-11-01

The paullon chalcone derivative KuRei300 is active against Leishmania donovani, the protozoans causing visceral leishmaniasis. The aim of this study was the development of a parenteral formulation of the virtually water insoluble compound in order to enable future studies in mice. Mixed lecithin/bile salt micelles, liposomes, supercooled smectic cholesterol myristate nanoparticles, cubic phase nanoparticles and a triglyceride emulsion were screened for their solubilizing properties. Due to the limited available amount of KuRei300 a passive loading approach with pre-formulated carriers that were incubated with drug substance deposited onto the walls of glass vials was used. The loading capacities of the nanocarriers, the influence of the solid state properties of the drug and its deposits on the loading results and chemical stability aspects of KuRei300 were investigated. Employed methods included HPLC, UV spectroscopy, (1)H NMR, XRPD, and DSC. All nanocarriers substantially improved the solubility of KuRei300; the mixed micelles exhibited the highest drug load. Related to the lipid matrix, however, the smectic nanoparticles solubilized the significantly highest amount of drug. Loading from physically altered drug deposits improved the obtainable concentration to the threefold compared with untreated drug powder. Formulations with KuRei300 must be stored excluded from light under a nitrogen atmosphere as the substance is susceptible to photoisomerization and decomposition. Copyright © 2013 Elsevier B.V. All rights reserved.

Strengthening of reinforced concrete beams with basalt-based FRP sheets: An analytical assessment

NASA Astrophysics Data System (ADS)

Nerilli, Francesca; Vairo, Giuseppe

2016-06-01

In this paper the effectiveness of the flexural strengthening of RC beams through basalt fiber-reinforced sheets is investigated. The non-linear flexural response of RC beams strengthened with FRP composites applied at the traction side is described via an analytical formulation. Validation results and some comparative analyses confirm soundness and consistency of the proposed approach, and highlight the good mechanical performances (in terms of strength and ductility enhancement of the beam) produced by basalt-based reinforcements in comparison with traditional glass or carbon FRPs.

Strengthening of reinforced concrete beams with basalt-based FRP sheets: An analytical assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nerilli, Francesca; Vairo, Giuseppe

2016-06-08

In this paper the effectiveness of the flexural strengthening of RC beams through basalt fiber-reinforced sheets is investigated. The non-linear flexural response of RC beams strengthened with FRP composites applied at the traction side is described via an analytical formulation. Validation results and some comparative analyses confirm soundness and consistency of the proposed approach, and highlight the good mechanical performances (in terms of strength and ductility enhancement of the beam) produced by basalt-based reinforcements in comparison with traditional glass or carbon FRPs.

Development of autoclave moldable addition-type polyimides

NASA Technical Reports Server (NTRS)

Vaughan, R. W.; Jones, R. J.; Orell, M. K.; Zakrzewski, G. A.

1976-01-01

Chemistry and processing modifications of the poly(Diels Alder) polyimide (PDA) resin were performed to obtain structural composites suitable for 589 K (600 F) service. This work demonstrated that the PDA resin formulation is suitable for service at 589 K (600 F) for up to 125 hours when used in combination with Hercules HTS graphite fiber. Sandwich panels were autoclave molded using PDA/HTS skins and polyimide/glass honeycomb core. Excellent adhesion between honeycomb core and the facing skins was demonstrated. Fabrication ease was demonstrated by autoclave molding three-quarter scale YF-12 wing panels.

Unidirectional fibers and polyurethane elastomer matrix based composites synthesis and properties. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Chakar, A.

1984-01-01

A study of the properties and manufacturing techniques for long-fiber reinforced elastomeric composites for flexible and damping structural materials is presented. Attention is given to the usage of polyurethane in the matrix to obtain plastic elastomeric matrices and vitreous transition temperatures which vary from -80 C to 10 C, as well as assure good fiber adhesion. Various polyurethane formulations synthesized from diisocyanate prepolymers are examined in terms of mechanical and thermal properties. The principal reinforcing fiber selected is a unidirectional glass cloth.

An analytical and experimental investigation of edge delamination in laminates subjected to tension, bending, and torsion

NASA Technical Reports Server (NTRS)

Chan, Wen S.

1989-01-01

An integrated two-dimensional finite element was developed to calculate interlaminar stresses and strain energy release rates for the study of delamination in composite laminates subjected to uniaxial tension, bending, and torsion loads. Addressed are the formulation, implementation, and verification of the model. Parametric studies were conducted on the effect of Poisson's ratio mismatch between plies and the stacking sequence on interlaminar stress, and on the effect of delamination opening height and delamination length, due to bending, on strain energy release rate for various laminates. A comparison of strain energy release rates in all-graphite and graphite/glass hybrid laminates is included. The preliminary results of laminates subjected to torsion are also included. Fatigue tension tests were conducted on Mode 1 and mixed mode edge-delamination coupons to establish the relationship between fatigue load vs. onset of delamination cycle. The effect on the fatigue delamination onset of different frequencies (1 and 5 Hz) was investigated for glass, graphite,and their hybrid laminates. Although a 20 percent increase in the static onset-of-delamination strength and a 10 percent increase in ultimate strength resulted from hybridizing the all-graphite laminate with a 90 deg glass ply, the fatigue onset is lower in the hybrid laminate than in the all-graphite laminate.

Relationship of Cure Temperature to Mechanical, Physical, and Dielectric Performance of PDMS Glass Composite for Electric Motor Insulation

NASA Technical Reports Server (NTRS)

Miller, Sandi G.; Becker, Kathleen; Williams, Tiffany S.; Scheiman, Daniel A.; McCorkle, Linda S.; Heimann, Paula J.; Ring, Andrew; Woodworth, Andrew

2017-01-01

Achieving NASAs aggressive fuel burn and emission reduction for N-plus-3 aircraft will require hybrid electric propulsion system in which electric motors driven by either power generated from turbine or energy storage system will power the fan for propulsion. Motors designed for hybrid electric aircraft are expected to operate at medium to high voltages over long durations in a high altitude service environment. Such conditions have driven research toward the development of wire insulation with improved mechanical strength, thermal stability and increased breakdown voltage. The silicone class of materials has been considered for electric wire insulation due to its inherent thermal stability, dielectric strength and mechanical integrity. This paper evaluates the dependence of these properties on the cure conditions of a polydimethyl-siloxane (PDMS) elastomer; where both cure temperature and base-to-catalyst ratio were varied. The PDMS elastomer was evaluated as a bulk material and an impregnation matrix within a lightweight glass veil support. The E-glass support was selected for mechanical stiffness and dielectric strength. This work has shown a correlation between cure conditions and material physical properties. Tensile strength increased with cure temperature whereas breakdown voltage tended to be independent of process variations. The results will be used to direct material formulation based on specific insulation requirements.

A computational study of diffusion in a glass-forming metallic liquid

DOE PAGES

Wang, T.; Zhang, F.; Yang, L.; ...

2015-06-09

In this study, liquid phase diffusion plays a critical role in phase transformations (e.g. glass transformation and devitrification) observed in marginal glass forming systems such as Al-Sm. Controlling transformation pathways in such cases requires a comprehensive description of diffusivity, including the associated composition and temperature dependencies. In our computational study, we examine atomic diffusion in Al-Sm liquids using ab initio molecular dynamics (AIMD) and determine the diffusivities of Al and Sm for selected alloy compositions. Non-Arrhenius diffusion behavior is observed in the undercooled liquids with an enhanced local structural ordering. Through assessment of our AIMD result, we construct a generalmore » formulation for Al-Sm liquid, involving a diffusion mobility database that includes composition and temperature dependence. A Volmer-Fulcher-Tammann (VFT) equation is adopted for describing the non-Arrhenius behavior observed in the undercooled liquid. Furthermore, the composition dependence of diffusivity is found quite strong, even for the Al-rich region contrary to the sole previous report on this binary system. The model is used in combination with the available thermodynamic database to predict specific diffusivities and compares well with reported experimental data for 0.6 at.% and 5.6 at.% Sm in Al-Sm alloys.« less

The Feasibility and Functional Performance of Ternary Borate-Filled Hydrophilic Bone Cements: Targeting Therapeutic Release Thresholds for Strontium

PubMed Central

MacDonald, Kathleen; Price, Richard B.; Boyd, Daniel

2017-01-01

We examine the feasibility and functionality of hydrophilic modifications to a borate glass reinforced resin composite; with the objective of meeting and maintaining therapeutic thresholds for Sr release over time, as a potential method of incorporating antiosteoporotic therapy into a vertebroplasty material. Fifteen composites were formulated with the hydrophilic agent hydroxyl ethyl methacrylate (HEMA, 15, 22.5, 30, 37.5 or 45 wt% of resin phase) and filled with a borate glass (55, 60 or 65 wt% of total cement) with known Sr release characteristics. Cements were examined with respect to degree of cure, water sorption, Sr release, and biaxial flexural strength over 60 days of incubation in phosphate buffered saline. While water sorption and glass degradation increased with increasing HEMA content, Sr release peaked with the 30% HEMA compositions, scanning electron microscope (SEM) imaging confirmed the surface precipitation of a Sr phosphate compound. Biaxial flexural strengths ranged between 16 and 44 MPa, decreasing with increased HEMA content. Degree of cure increased with HEMA content (42 to 81%), while no significant effect was seen on setting times (209 to 263 s). High HEMA content may provide a method of increasing monomer conversion without effect on setting reaction, providing sustained mechanical strength over 60 days. PMID:28708123

The Feasibility and Functional Performance of Ternary Borate-Filled Hydrophilic Bone Cements: Targeting Therapeutic Release Thresholds for Strontium.

PubMed

MacDonald, Kathleen; Price, Richard B; Boyd, Daniel

2017-07-14

We examine the feasibility and functionality of hydrophilic modifications to a borate glass reinforced resin composite; with the objective of meeting and maintaining therapeutic thresholds for Sr release over time, as a potential method of incorporating antiosteoporotic therapy into a vertebroplasty material. Fifteen composites were formulated with the hydrophilic agent hydroxyl ethyl methacrylate (HEMA, 15, 22.5, 30, 37.5 or 45 wt% of resin phase) and filled with a borate glass (55, 60 or 65 wt% of total cement) with known Sr release characteristics. Cements were examined with respect to degree of cure, water sorption, Sr release, and biaxial flexural strength over 60 days of incubation in phosphate buffered saline. While water sorption and glass degradation increased with increasing HEMA content, Sr release peaked with the 30% HEMA compositions, scanning electron microscope (SEM) imaging confirmed the surface precipitation of a Sr phosphate compound. Biaxial flexural strengths ranged between 16 and 44 MPa, decreasing with increased HEMA content. Degree of cure increased with HEMA content (42 to 81%), while no significant effect was seen on setting times (209 to 263 s). High HEMA content may provide a method of increasing monomer conversion without effect on setting reaction, providing sustained mechanical strength over 60 days.

Sorbitol crystallization-induced aggregation in frozen mAb formulations.

PubMed

Piedmonte, Deirdre Murphy; Hair, Alison; Baker, Priti; Brych, Lejla; Nagapudi, Karthik; Lin, Hong; Cao, Wenjin; Hershenson, Susan; Ratnaswamy, Gayathri

2015-02-01

Sorbitol crystallization-induced aggregation of mAbs in the frozen state was evaluated. The effect of protein aggregation resulting from sorbitol crystallization was measured as a function of formulation variables such as protein concentration and pH. Long-term studies were performed on both IgG1 and IgG2 mAbs over the protein concentration range of 0.1-120 mg/mL. Protein aggregation was measured by size-exclusion HPLC (SE-HPLC) and further characterized by capillary-electrophoresis SDS. Sorbitol crystallization was monitored and characterized by subambient differential scanning calorimetry and X-ray diffraction. Aggregation due to sorbitol crystallization is inversely proportional to both protein concentration and formulation pH. At high protein concentrations, sorbitol crystallization was suppressed, and minimal aggregation by SE-HPLC resulted, presumably because of self-stabilization of the mAbs. The glass transition temperature (Tg ') and fragility index measurements were made to assess the influence of molecular mobility on the crystallization of sorbitol. Tg ' increased with increasing protein concentration for both mAbs. The fragility index decreased with increasing protein concentration, suggesting that it is increasingly difficult for sorbitol to crystallize at high protein concentrations. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Solutions as solutions--synthesis and use of a liquid polyester excipient to dissolve lipophilic drugs and formulate sustained-release parenterals.

PubMed

Asmus, Lutz R; Gurny, Robert; Möller, Michael

2011-11-01

Solid poly(lactides) and poly(lactide-co-glycolides) are widely used polymers for sustained-release parenterals. However, they have some unfavorable properties regarding manufacturing of the formulations and administration to the patient due to their solid aggregate state. In contrast, hexyl-substituted poly(lactic acid) (hexPLA, poly(2-hydroxyoctanoic acid)) is a viscous degradable polyester. To date, a two-step ring-opening polymerization was used for its synthesis. Here, we investigated a novel one-pot one-step melt polycondensation method to prepare hexPLA for biomedical applications by a simple green chemistry process. No catalyst or solely pharmaceutically acceptable catalysts and environmentally friendly purification methods without organic solvents were used. The resulting hexPLA polymers are stable under dry heat sterilization conditions. Low molecular weight hexPLAs with less than 5000 g/mol are less viscous than high molecular weight polymers. HexPLA can dissolve lipophilic active substances, with generally high incorporation capacities in low molecular weight polymers. The incorporation of solid compounds increases the viscosity and glass transition temperature, whereas the addition of small amounts of plasticizers or sparse warming significantly decreases the viscosity. Loratadine is soluble in hexPLA up to 28%. This highly concentrated Loratadine-hexPLA formulation released the active compound entirely over 14 days without initial burst in a zero order kinetic, matching the clinical requirements for such a sustained-release formulation. This demonstrates the potential of hexPLA as an excipient for injectable sustained-release formulations. Copyright © 2011 Elsevier B.V. All rights reserved.

Laboratory and scaled up evaluation of cis-permethrin applied as a new ultra low volume formulation against Aedes aegypti (Diptera: Culicidae).

PubMed

Seccacini, Emilia; Masuh, Héctor; Licastro, Susana A; Zerba, Eduardo Nicolás

2006-01-01

Ultra low volume (ULV) aerial spraying is a common methodology for spatial treatments for Aedes aegypti (L.) control. Previous studies from our laboratory indicated that the cis isomer of permethrin has an excellent efficacy for vector control, in particular for Triatoma infestans. It was of interest to determine the efficacy of this pure isomer in a ULV water-based formulation for adult A. aegypti control, since both vectors usually are found together in South America. A method is presented to make a quick measure at laboratory level of the knock down effect (KT50) of a new EC water-based formulation of cis-permethrin, in a small Peet Grady chamber of 0.34 m3, with a specially designed glass sprayer. A deltamethrin standard ULV formulation "CISLIN" was used for comparison. cis-Permethrin showed a significantly lower KT50 value than deltamethrin (7.50 and 9.65 min, respectively). When the mosquitoes were introduced into the chamber 10 min after spraying KT50 values were almost equal (15.59 and 15.88 min, respectively). In scaled up bioassays the ULV formulation of cis-permethrin showed 100% mortality of A. aegypti adult mosquitoes at the beginning of the treatment (t=0) and some mortality at 1h post treatment of freshly introduced mosquitoes. It was concluded that cis-permethrin could be an excellent tool for control of A. aegypti and other vectors of medical importance, with fewer side effects and better cost-effectiveness than with the cyanopyrethroids.

Maintaining a stationary laser footprint during angular scan in internal-reflection experiments.

PubMed

Fontana, Eduardo; Cavalcanti, Gustavo Oliveira

2013-11-10

In internal-reflection metrology using prisms, the prism is usually mounted on a rotation/translation stage to enable adjusting angle and location of the laser footprint on the surface. If a visual inspection method is used to find the laser footprint, the task becomes impossible if invisible radiation in the near infrared is employed. In addition, it may be desirable to perform angular scan experiments with a stationary footprint on the surface during scans, or even to automatically probe specific points on an extended prism face for predetermined incidence angles. In this paper, a formulation is developed to determine the required translation along the prism face to allow maintaining the laser footprint stationary under a given rotation. A web-based app developed under the scope of this work demonstrates the applicability of the approach for silica, BK7 and SF2 glasses, in the wavelength range from 500 to 1500 nm and for an arbitrary geometry of the glass prism.

Improvement of fish freshness determination method by the application of amorphous freeze-dried enzymes.

PubMed

Srirangsan, Paveena; Hamada-Sato, Naoko; Kawai, Kiyoshi; Watanabe, Manabu; Suzuki, Toru

2010-12-08

Alkaline phosphatase (ALP), nucleoside phosphorylase (NP), and xanthine oxidase (XOD) were used in a colorimetric method for evaluation of fish freshness based on the Ki value. Two enzyme mixtures, NP-XOD and ALP-NP-XOD, were prepared with a color developing agent, and stabilities of the enzymes were improved by freeze-drying with glass-forming additives, i.e., sucrose and sucrose-gelatin. As a result, a linear relationship was obtained between the Ki values determined by the developed colorimetric method and a conventional high-performance liquid chromatography with a high correlation coefficient of 0.997. All enzyme samples containing the additive(s) were amorphous, and higher enzymes activities were maintained compared to those freeze-dried without an additive. Sucrose-gelatin/enzyme mixtures showed higher glass transition temperature; consequently, the enzymes were better stabilized than the sucrose/enzyme formulations. Using the sucrose-gelatin/enzyme mixture, Ki values of fish meat could be accurately determined even after 6-month storage of the dried enzymes at 40 °C.

Nanoengineering of bioactive glasses: hollow and dense nanospheres

NASA Astrophysics Data System (ADS)

Luz, Gisela M.; Mano, João F.

2013-02-01

The possibility of engineering bioactive glass (BG) nanoparticles into suitable sizes and shapes represents a significant achievement regarding the development of new osteoconductive biomaterials for therapeutic strategies to replace or regenerate damaged mineralised tissues. Herein we report the structural and chemical evolution of sol-gel derived BG nanoparticles for both the binary (SiO2:CaO (mol%) = 70:30) and ternary (SiO2:CaO:P2O5 (mol%) = 55:40:5) formulations, in order to understand how the particles formation can be directed. Hollow BG nanospheres were obtained through Ostwald ripening. The presence of a non ionic surfactant, poly(ethylene glycol) (PEG), allowed the formation of dense BG nanospheres with controllable diameters depending on the molecular weight of PEG. A deep insight into the genesis of BG nanoparticles formation is essential to design BG based materials with controlled compositions, morphologies and sizes at the nanoscale, in order to improve their performance in orthopaedic applications including bone tissue engineering.

Self-assembly of colloid-cholesteric composites provides a possible route to switchable optical materials

NASA Astrophysics Data System (ADS)

Stratford, K.; Henrich, O.; Lintuvuori, J. S.; Cates, M. E.; Marenduzzo, D.

2014-06-01

Colloidal particles dispersed in liquid crystals can form new materials with tunable elastic and electro-optic properties. In a periodic ‘blue phase’ host, particles should template into colloidal crystals with potential uses in photonics, metamaterials and transformational optics. Here we show by computer simulation that colloid/cholesteric mixtures can give rise to regular crystals, glasses, percolating gels, isolated clusters, twisted rings and undulating colloidal ropes. This structure can be tuned via particle concentration, and by varying the surface interactions of the cholesteric host with both the particles and confining walls. Many of these new materials are metastable: two or more structures can arise under identical thermodynamic conditions. The observed structure depends not only on the formulation protocol but also on the history of an applied electric field. This new class of soft materials should thus be relevant to design of switchable, multistable devices for optical technologies such as smart glass and e-paper.

Sol-Gel Glass Holographic Light-Shaping Diffusers

NASA Technical Reports Server (NTRS)

Yu, Kevin; Lee, Kang; Savant, Gajendra; Yin, Khin Swe (Lillian)

2005-01-01

Holographic glass light-shaping diffusers (GLSDs) are optical components for use in special-purpose illumination systems (see figure). When properly positioned with respect to lamps and areas to be illuminated, holographic GLSDs efficiently channel light from the lamps onto specified areas with specified distributions of illumination for example, uniform or nearly uniform irradiance can be concentrated with intensity confined to a peak a few degrees wide about normal incidence, over a circular or elliptical area. Holographic light diffusers were developed during the 1990s. The development of the present holographic GLSDs extends the prior development to incorporate sol-gel optical glass. To fabricate a holographic GLSD, one records a hologram on a sol-gel silica film formulated specially for this purpose. The hologram is a quasi-random, micro-sculpted pattern of smoothly varying changes in the index of refraction of the glass. The structures in this pattern act as an array of numerous miniature lenses that refract light passing through the GLSD, such that the transmitted light beam exhibits a precisely tailored energy distribution. In comparison with other light diffusers, holographic GLSDs function with remarkably high efficiency: they typically transmit 90 percent or more of the incident lamp light onto the designated areas. In addition, they can withstand temperatures in excess of 1,000 C. These characteristics make holographic GLSDs attractive for use in diverse lighting applications that involve high temperatures and/or requirements for high transmission efficiency for ultraviolet, visible, and near-infrared light. Examples include projectors, automobile headlights, aircraft landing lights, high-power laser illuminators, and industrial and scientific illuminators.

Monolithic graded-refractive-index glass-based antireflective coatings. Broadband/omnidirectional light harvesting and self-cleaning characteristics

DOE PAGES

Aytug, Tolga; Lupini, Andrew R.; Jellison, Gerald E.; ...

2015-04-23

The design of multifunctional coatings impact impact the performance of many optical systems and components. Such coatings should be mechanically robust, and combine user-defined optical and wetting functions with scalable fabrication formulations. By taking cues from the properties of some natural biological structures, we report here the formation of low-refractive index antireflective glass films that embody omni-directional optical properties over a wide range of wavelengths, while also possessing specific wetting capabilities. The coatings comprise an interconnected network of nanoscale pores surrounded by a nanostructured silica framework. These structures result from a novel fabrication method that utilizes metastable spinodal phase separationmore » in glass-based materials. The approach not only enables design of surface microstructures with graded-index antireflection characteristics, where the surface reflection is suppressed through optical impedance matching between interfaces, but also facilitates self-cleaning ability through modification of the surface chemistry. Based on near complete elimination of Fresnel reflections (yielding >95% transmission through a single-side coated glass) and corresponding increase in broadband transmission, the fabricated nanostructured surfaces are found to promote a general and an invaluable ~3–7% relative increase in current output of multiple direct/indirect bandgap photovoltaic cells. Moreover, these antireflective surfaces also demonstrate superior resistance against mechanical wear and abrasion. Unlike conventional counterparts, the present antireflective coatings are essentially monolithic, enabling simultaneous realization of graded index anti-reflectivity, self-cleaning capability, and mechanical stability within the same surface. Moreover, the concept represents a fundamental basis for development of advanced coated optical quality products, especially where environmental exposure is required.« less

Container/Closure Integrity Testing and the Identification of a Suitable Vial/Stopper Combination for Low-Temperature Storage at -80 {degrees}C.

PubMed

Zuleger, Brigitte; Werner, Uwe; Kort, Alexander; Glowienka, Rene; Wehnes, Engelbert; Duncan, Derek

2012-01-01

It was recently found that after storage of a live viral vaccine at -80 °C in glass vials closed with rubber stoppers, a phenomenon was revealed which had not been observed before with other viral products stored at -20 °C: overpressure in the vials. As this phenomenon poses a serious safety problem for medical personnel as well as for the product itself, an investigation was initiated to identify the root cause of the overpressure. After exclusion of possible root causes (differences in air temperature or atmospheric air pressure during filling and quality control testing, outgassing from the formulation buffer) the remaining hypothesis involved a possible container closure integrity issue at low temperature. The glass transition temperatures (T(g)) of many rubber stopper formulations are in the range -55 to -70 °C. At storage temperatures below T(g), the rubber stopper loses its elastic properties and there is a risk that the seal integrity of the vial could be compromised. Loss of seal integrity of the vials near storage temperatures of -80 °C would result in an ingress of cold dense gas into the vial headspace. After removal of the vials from storage at -80 °C, the rubber stoppers could regain their elastic properties and the vials would quickly reseal, thereby trapping the ingressed gas, which leads to overpressure in the vial headspace. Nondestructive laser-based headspace analysis was used to investigate the maintenance of container closure integrity as a function of the filling and capping/crimping process, storage and transport conditions, and vial/stopper designs. This analytical method is based on frequency modulation spectroscopy (FMS) and can be used for noninvasive headspace measurements of headspace pressure and headspace gas composition. Changes in the vial headspace composition and/or pressure are a clear marker for vials that have lost container closure integrity. After storage of a live viral vaccine at -80 °C in glass vials closed with rubber stoppers, overpressure in some of the vials was observed, posing a serious safety problem for medical personnel as well as for the product. A working hypothesis to explain this phenomenon involved a possible container closure integrity issue at these low temperatures. The glass transition temperatures (T(g)) of many rubber stopper formulations are in the range -55 to -70 °C. At storage temperatures below T(g), the rubber stopper loses its elastic properties, resulting in compromised seal integrity of the vial and ingress of cold dense gas into the vial headspace. Upon thawing, the rubber stoppers regain their elastic properties and the vials quickly reseal, thereby trapping the ingressed gas, which leads to overpressure in the vial headspace. Nondestructive, laser-based headspace analysis, which is able to detect changes in headspace pressure and gas composition, was used to investigate the maintenance of container closure integrity. Changes in the vial headspace composition and/or pressure are a clear marker for vials that have lost container closure integrity.

Study of the weathering effect in a natural environment on the hybrid kenaf bast/glass fibre-filled unsaturated polyester composite

NASA Astrophysics Data System (ADS)

Mohammed, Mohammed; Rozyanty, A. R.; Adam, Tijjani; Betar, Bashir O.

2017-09-01

In this research, we prepared pure kenaf composites and kenaf/glass fibre hybrid composites using the hand lay-up procedure. Also, we studied the weather effects on the mechanical, morphological and thermal properties of the pure kenaf and the kenaf/glass fibre hybrid composites. Before the weathering conditions, we determined that the tensile strength of the kenaf /glass fibre hybrid composite was 70.9 MPa, while the tensile modulus was 3030 MPa. However, during the first weathering month, there was a decrease in the tensile modulus values, which further decreased as the weathering continued. Also, there was a significant difference in the tensile modulus reduced values between the pure kenaf and the glass fibre-reinforced kenaf composites, which indicated that the glass fibre was a good reinforcement option, and could be successfully used for producing high performing composites. Based on the flexural strength results obtained, it could be noted that the natural fibre composites could not withstand the environmental conditions, as they displayed poor wettability, a higher moisture adsorption and were incompatible with some of the polymeric matrices. As they had higher moisture absorption properties, they formed voids within the composites that could decrease the composite mechanical properties like the flexural strength or the flexural modulus, which was supported BY our SEM results. However, some of the modifications do tend to improve the mechanical properties, which help in improving the composite performance with a proper composite formulation during modification. Our results showed that the thermal properties of the kenaf and the kenaf hybrid composites are significantly affected by the weather, wherein the composites display a slow and gradual initial weight loss till a massive weight loss was observed at temperatures around 390°C. However, as the weathering increased, the weight loss was seen to occur at even low temperatures of 290°C. This phenomenon was because of the moisture absorption, which was seen to increase it, and the moisture weakened the molecular interfacial bonds.

Development and effect of different bioactive silicate glass scaffolds: in vitro evaluation for use as a bone drug delivery system.

PubMed

Soundrapandian, Chidambaram; Mahato, Arnab; Kundu, Biswanath; Datta, Someswar; Sa, Biswanath; Basu, Debebrata

2014-12-01

Local drug delivery systems to bone have attracted appreciable attention due to their efficacy to improve drug delivery, healing and regeneration. In this paper, development and characterization of new formulations of bioactive glass into a porous scaffold has been reported for its suitability to act as a drug delivery system in the management of bone infections, in vitro. Two new glass compositions based on SiO2-Na2O-ZnO-CaO-MgO-P2O5 system (BGZ and MBG) have been developed which after thorough chemical and phase evaluation, studied for acellular static in vitro bioactivity in SBF. Porous scaffolds made of these glasses have been fabricated and characterized thoroughly for bioactivity study, SEM, XRD, in vitro cytotoxicity, MTT assay and wound healing assay using human osteocarcoma cells. Finally, gatifloxacin was loaded into the porous scaffold by vacuum infiltration method and in vitro drug release kinetics have been studied with varying parameters including dissolution medium (PBS and SBF) and with/without impregnation chitosan. Suitable model has also been proposed for the kinetics. 63-66% porous and 5-50μm almost unimodal porous MBG and BGZ bioactive glass scaffolds were capable of releasing drugs successfully for 43 days at concentrations to treat orthopedic infections. In addition, it was also observed that the release of drug followed Peppas-Korsmeyer release pattern based on Fickian diffusion, while 0.5-1% chitosan coating on the scaffolds decreased the burst release and overall release of drug. The results also indicated that MBG based scaffolds were bioactive, biocompatible, noncytotoxic and exhibited excellent wound healing potential while BGZ was mildly cytotoxic with moderate wound healing potential. These results strongly suggest that MBG scaffolds appear to be a suitable bone drug delivery system in orthopedic infections treatment and as bone void fillers, but BGZ should be handled with caution or studied elaborately in detail further to ascertain and confirm the cytotoxic nature and wound healing potential of this glass. Copyright © 2014 Elsevier Ltd. All rights reserved.

Failure waves in glass and ceramics under shock compression

NASA Astrophysics Data System (ADS)

Brar, N. S.

2000-04-01

The response of various types of glasses (fused silica, borosilicates, soda-lime, and lead filled) to shock wave loading, especially the failure of glass behind the shock wave through the "so called" failure wave or front, has been the subject of intense research among a number of investigators. The variations in material properties across this front include complete loss of tensile (spall) strength, loss in shear strength, reduction in acoustic impedance and opacity to light. Both the Stress and velocity history from VISAR measurements have shown that the failure front propagates at a speed of 1.5 to 2.5 mm/s, depending on the peak shock stress. The shear strength [τ=1/2(σ1-σ2)] behind the failure front, determined using embedded transverse gauges, is found to decrease to about 1 GPa for soda-lime, borosilicate, and filled glasses. Optical (high-speed photography) observations also confirm formation of this failure front. There is a general agreement among various researchers on these failure observations. However, three proposed mechanisms for the formation of failure front are based on totally different formulations. The first, due to Clifton, is based on the hypothesis of densification of glass under shock compression. Densification is followed by shear failure around inhomogeneities resulting in a phase boundary between the comminuted and the intact material. The second, proposed by Grady, involves the transfer of elastic shear strain energy to dilatant strain energy as a result of severe micro-cracking originating from impact. The third, by Espinosa and Brar, proposes that the front is created through shear micro-cracks, which nucleate and propagate from the impact face; as originally suggested by Kanel. This later mechanism is supported by the observed loss of shear strength of glass by Clifton et al. at shock stress above the threshold level. Espinosa has incorporated this mechanism in multiple-plane model and simulations predict the increase in lateral stress and an observed reduction in spall strength behind the failure front. Failure front studies, in terms of loss of shear strength, have been recently extended to alumina and SiC ceramics by Bourne et al.

Design and Evaluation of Topical Diclofenac Sodium Gel Using Hot Melt Extrusion Technology as a Continuous Manufacturing Process with Kolliphor® P407.

PubMed

Pawar, Jaywant; Narkhede, Rajkiran; Amin, Purnima; Tawde, Vaishali

2017-08-01

The aim of the present context was to develop and evaluate a Kolliphor® P407-based transdermal gel formulation of diclofenac sodium by hot melt extrusion (HME) technology; central composite design was used to optimize the formulation process. In this study, we have explored first time ever HME as an industrially feasible and continuous manufacturing technology for the manufacturing of gel formulation using Kolliphor® P407 and Kollisolv® PEG400 as a gel base. Diclofenac sodium was used as a model drug. The HME parameters such as feeding rate, screw speed, and barrel temperature were crucial for the semisolid product development, and were optimized after preliminary trials. For the processing of the gel formulation by HME, a modified screw design was used to obtain a uniform product. The obtained product was evaluated for physicochemical characterization such as differential scanning calorimetry (DSC), X-ray diffraction (XRD), pH measurement, rheology, surface tension, and texture profile analysis. Moreover, it was analyzed for general appearance, spreadibility, surface morphology, and drug content. The optimized gel formulation showed homogeneity and transparent film when applied on a glass slide under microscope, pH was 7.02 and uniform drug content of 100.04 ± 2.74 (SD = 3). The DSC and XRD analysis of the HME gel formulation showed complete melting of crystalline API into an amorphous form. The Kolliphor® P407 and Kollisolv® PEG400 formed excellent gel formulation using HME with consistent viscoelastic properties of the product. An improved drug release was found for the HME gel, which showed a 100% drug release than that of a marketed product which showed only 88% of drug release at the end of 12 h. The Flux value of the HME gel was 106 than that of a marketed formulation, which showed only about 60 value, inferring a significant difference (P < 0.05) at the end of 1 h. This study demonstrates a novel application of the hot melt extrusion process for manufacturing of topical semisolid products.

Effect of boron oxide addition on fibre drawing, mechanical properties and dissolution behaviour of phosphate-based glass fibres with fixed 40, 45 and 50 mol% P2O5

PubMed Central

Sharmin, Nusrat; Parsons, Andrew J; Rudd, Chris D

2014-01-01

Previous studies investigating manufacture of phosphate-based glass fibres from glasses fixed with P2O5 content less than 50 mol% showed that continuous manufacture without breakage was very difficult. In this study, nine phosphate-based glass formulations from the system P2O5-CaO-Na2O-MgO-B2O3 were prepared with P2O5 contents fixed at 40, 45 and 50 mol%, where Na2O was replaced by 5 and 10 mol% B2O3 and MgO and CaO were fixed to 24 and 16 mol%, respectively. The effect of B2O3 addition on the fibre drawing, fibre mechanical properties and dissolution behaviour was investigated. It was found that addition of 5 and 10 mol% B2O3 enabled successful drawing of continuous fibres from glasses with phosphate (P2O5) contents fixed at 40, 45 and 50 mol%. The mechanical properties of the fibres were found to significantly increase with increasing B2O3 content. The highest tensile strength (1200 ± 130 MPa) was recorded for 45P2O5-16CaO-5Na2O-24MgO-10B2O3 glass fibres. The fibres were annealed, and a comparison of the mechanical properties and mode of degradation of annealed and non-annealed fibres were investigated. A decrease in tensile strength and an increase in tensile modulus were observed for the annealed fibres. An assessment of the change in mechanical properties of both the annealed and non-annealed fibres was performed in phosphate-buffered saline (PBS) at 37℃ for 28 and 60 days, respectively. Initial loss of mechanical properties due to annealing was found to be recovered with degradation. The B2O3-containing glass fibres were found to degrade at a much slower rate as compared to the non-B2O3-containing fibres. Both annealed and non-annealed fibres exhibited a peeling effect of the fibre's outer layer during degradation. PMID:24939962

Effect of boron oxide addition on fibre drawing, mechanical properties and dissolution behaviour of phosphate-based glass fibres with fixed 40, 45 and 50 mol% P2O5.

PubMed

Sharmin, Nusrat; Parsons, Andrew J; Rudd, Chris D; Ahmed, Ifty

2014-11-01

Previous studies investigating manufacture of phosphate-based glass fibres from glasses fixed with P2O5 content less than 50 mol% showed that continuous manufacture without breakage was very difficult. In this study, nine phosphate-based glass formulations from the system P2O5-CaO-Na2O-MgO-B2O3 were prepared with P2O5 contents fixed at 40, 45 and 50 mol%, where Na2O was replaced by 5 and 10 mol% B2O3 and MgO and CaO were fixed to 24 and 16 mol%, respectively. The effect of B2O3 addition on the fibre drawing, fibre mechanical properties and dissolution behaviour was investigated. It was found that addition of 5 and 10 mol% B2O3 enabled successful drawing of continuous fibres from glasses with phosphate (P2O5) contents fixed at 40, 45 and 50 mol%. The mechanical properties of the fibres were found to significantly increase with increasing B2O3 content. The highest tensile strength (1200 ± 130 MPa) was recorded for 45P2O5-16CaO-5Na2O-24MgO-10B2O3 glass fibres. The fibres were annealed, and a comparison of the mechanical properties and mode of degradation of annealed and non-annealed fibres were investigated. A decrease in tensile strength and an increase in tensile modulus were observed for the annealed fibres. An assessment of the change in mechanical properties of both the annealed and non-annealed fibres was performed in phosphate-buffered saline (PBS) at 37℃ for 28 and 60 days, respectively. Initial loss of mechanical properties due to annealing was found to be recovered with degradation. The B2O3-containing glass fibres were found to degrade at a much slower rate as compared to the non-B2O3-containing fibres. Both annealed and non-annealed fibres exhibited a peeling effect of the fibre's outer layer during degradation. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Silicate release from glass for pharmaceutical preparations.

PubMed

Bohrer, Denise; Bortoluzzi, Fabiana; Nascimento, Paulo Cícero; Carvalho, Leandro Machado; Ramirez, Adrian Gustavo

2008-05-01

Glass is made of polymeric silica and other minor components, which are necessary for turning the silica into a material more easily moldable and resistant to temperature changes. Glass containers for pharmaceutical usage are classified according to their resistance to a chemical attack, a test carried out in the presence of water and heat. The test is designed to show the released alkalinity, a variable dependent on the amount of sodium oxide, one of the minor components added to the glass mass. In this work, the release of silica from glass by action of constituents from pharmaceutical formulations was investigated. The study included products used in large volumes and usually stored in glass containers. Solutions of amino acids, electrolytes, glucose, oligoelements and others such as heparin and sodium bicarbonate were individually stored in glass containers and heated at 121 degrees C for 30min, as in the water attack test. The test was also carried out only with water, where the pH varied from 2 to 12. The released silicate was measured either by photometry or atomic absorption spectrometry, depending on the nature of the sample. The results showed that silicate is released during the heating cycle even if the contact is with pure water only. The pH exerts a considerable influence on the release, being that the higher the pH, the higher the silica dissolved. An elevated pH, however, is not the only factor responsible for silica dissolution. While in the solutions of NaCl, KCl, Mg Cl2 and ZnSO4 and in most of the amino acids, the concentration of silicate was as high as in pure water (0.1-1.0mg Si/L). In the solutions of sodium acetate, bicarbonate and gluconate, its concentration was much higher, over 30mg Si/L. These results were confirmed by the analysis of commercial products, where in solutions of amino acids the level of silicate ranged from 0.14 to 0.19mg Si/L. On the other hand, calcium gluconate, sodium bicarbonate and potassium phosphate presented silicate levels from 1 to 4mg/L. Although silica is not considered a toxic substance for humans, it is necessary to be aware of its presence in solutions for parenteral nutrition due to the direct introduction into the bloodstream and the large volume usually administrated, even to pre-term infants.

Stability of Extemporaneously Compounded Dexamethasone in Glass and Plastic Bottles and Plastic Syringes

PubMed Central

Ensom, Mary H H; Décarie, Diane

2014-01-01

Background Dexamethasone is widely used to treat rheumatic and endocrine disorders and chemotherapy-induced nausea and vomiting. A palatable, alcohol-free liquid formulation, with a suitable concentration to allow reasonable administration volume, is available only via extemporaneous compounding. Objective: To evaluate the stability of dexamethasone suspensions in commercially available vehicles (Oral Mix and Oral Mix SF) in various types of containers after storage at 25°C and 4°C for up to 91 days. Methods: Dexamethasone suspensions (1 mg/mL) were prepared in Oral Mix and Oral Mix SF and then transferred to amber glass and plastic prescription bottles and plastic oral syringes. Suspensions in all 3 types of containers were stored at 25°C; suspensions in glass and plastic bottles were also stored at 4°C. Samples were collected weekly from each container up to 28 days and then every 2 weeks up to 91 days. The samples were analyzed by a validated, stability-indicating high-performance liquid chromatography − ultraviolet detection method. A suspension was considered stable if it maintained at least 90% of its initial dexamethasone concentration. Changes in colour, taste, odour, precipitation (and ease of resuspension), and pH were used to assess physical compatibility. Results: All suspensions maintained at least 96% of the original concentration for up to 91 days with storage at 25°C or at 4°C. No notable changes in colour, taste, odour, precipitation, or pH were observed over the 91-day period. Conclusion: Dexamethasone suspensions (1 mg/mL) in Oral Mix and Oral Mix SF, stored in amber glass or plastic bottles or plastic syringes at 25°C or in amber glass or plastic bottles at 4°C can be expected to remain stable for up to 91 days. PMID:25214658

A Hierarchical System for Evaluating the Biogenicity of Metavolcanic- and Ultramafic-Hosted Microalteration Textures in the Search for Extraterrestrial Life.

PubMed

McLoughlin, Nicola; Grosch, Eugene G

2015-10-01

The low-temperature alteration of submarine volcanic glasses has been argued to involve the activity of microorganisms, and analogous fluid-rock-microbial-mediated alteration has also been postulated on Mars. However, establishing the extent to which microbes are involved in volcanic glass alteration has proven to be difficult, and the reliability of resulting textural biosignatures is debated, particularly in the early rock record. We therefore propose a hierarchical scheme to evaluate the biogenicity of candidate textural biosignatures found in altered terrestrial and extraterrestrial basaltic glasses and serpentinized ultramafic rocks. The hierarchical scheme is formulated to give increasing confidence of a biogenic origin and involves (i) investigation of the textural context and syngenicity of the candidate biosignature; (ii) characterization of the morphology and size range of the microtextures; (iii) mapping of the geological and physicochemical variables controlling the occurrence and preservation of the microtextures; (iv) in situ investigation of chemical signatures that are syngenetic to the microtexture; and (v) identification of growth patterns suggestive of biological behavior and redox variations in the host minerals. The scheme results in five categories of candidate biosignature as follows: Category 1 indicates preservation of very weak evidence for biogenicity, Categories 2 through 4 indicate evidence for increasing confidence of a biogenic origin, and Category 5 indicates that biogenic origin is most likely. We apply this hierarchical approach to examine the evidence for a biogenic origin of several examples, including candidate bacterial encrustations in altered pillow lavas, granular and tubular microtextures in volcanic glass from the subseafloor and a Phanerozoic ophiolite, mineralized microtextures in Archean metavolcanic glass, and alteration textures in olivines of the martian meteorite Yamato 000593. The aim of this hierarchical approach is to provide a framework for identifying robust biosignatures of microbial life in the altered oceanic crust on Earth, and in extraterrestrial altered mafic-ultramafic rocks, particularly on Mars.

Inhibiting Sterilization-Induced Oxidation of Large Molecule Therapeutics Packaged in Plastic Parenteral Vials.

PubMed

Vieregg, Jeffrey R; Martin, Steven J; Breeland, Adam P; Weikart, Christopher M; Tirrell, Matthew V

2018-01-01

For many years, glass has been the default material for parenteral packaging, but the development of advanced plastics such as cyclic olefin polymers and the rapidly increasing importance of biologic drugs have provided new choices, as well as more stringent performance requirements. In particular, many biologics must be stored at non-neutral pH, where glass is susceptible to hydrolysis, metal extraction, and delamination. Plastic containers are not susceptible to these problems, but suffer from higher gas permeability and a propensity for sterilization-induced radical generation, heightening the risk of oxidative damage to sensitive drugs. This study evaluates the properties of a hybrid material, SiOPlas™, in which an ultrathin multilayer coating is applied to the interior of cyclic olefin polymer containers via plasma-enhanced chemical vapor deposition. Our results show that the coating decreases oxygen permeation through the vial walls 33-fold compared to uncoated cyclic olefin polymers, which should allow for improved control of oxygen levels in sensitive formulations. We also measured degradation of two biologic drugs that are known to be sensitive to oxidation, teriparatide and erythropoietin, in gamma and electron beam sterilized SiOPlas™, glass, and uncoated cyclic olefin polymer vials. In both cases, solutions stored in SiOPlas™ vials did not show elevated susceptibility to oxidation compared to either glass or unsterilized controls. Taken together, these results suggest that hybrid materials such as SiOPlas™ are attractive choices for storing high-value biologic drugs. LAY ABSTRACT: One of the most important functions of parenteral drug containers is safeguarding their contents from damage, either chemical or physical. Glass has been the container material of choice for many years, but concerns over breakage and vulnerability to chemical attack at non-neutral pH have spurred the rise of advanced plastics as alternatives. Plastics solve many problems associated with glass but introduce several of their own, including increased gas permeation and generation of oxidizing radicals during sterilization. In this article, we evaluate SiOPlas™, a hybrid material consisting of plastic with a thin multilayer coating applied to the interior, for its ability to overcome these two problems. We find that SiOPlas™ is much less permeable to oxygen than uncoated plastic, and that two biologic drugs stored in gamma and electron beam sterilized SiOPlas™ vials do not display elevated levels of oxidation compared to either glass or unsterilized vials. This suggests that hybrid materials such as SiOPlas™ can exhibit the best qualities of both glass and plastic, making them attractive materials for storing high-value parenteral drugs. © PDA, Inc. 2018.

Surface properties and bond strength measurements of N-vinylcaprolactam (NVC)-containing glass-ionomer cements.

PubMed

Moshaverinia, Alireza; Chee, Winston W; Brantley, William A; Schricker, Scott R

2011-03-01

N-vinylcaprolactam (NVC)-containing glass ionomers are promising dental restorative materials with improved mechanical properties; however, little information is available on other physical characteristics of these types of modified glass ionomers, especially their surface properties. Understanding the surface characteristics and behavior of glass ionomers is important for understanding their clinical behavior and predictability as dental restorative materials. The purpose of this study was to investigate the effect of NVC-containing terpolymers on the surface properties and bond strength to dentin of GIC (glass-ionomer cement), and to evaluate the effect of NVC-containing terpolymer as a dentin conditioner. The terpolymer of acrylic acid (AA)-itaconic acid (IA)-N-vinylcaprolactam (NVC) with a molar ratio of 8:1:1 (AA:IA:NVC) was synthesized by free radical polymerization and characterized using nuclear magnetic resonance ((1)H-NMR) and Fourier transform infrared spectroscopy (FTIR). The synthesized terpolymer was used in glass-ionomer cement formulations (Fuji IX GP). Ten disc-shaped specimens (12 × 1 mm) were mixed and fabricated at room temperature. Surface properties (wettability) of modified cements were studied by contact angle measurements as a function of time. Work of adhesion values of different surfaces were also determined. The effect of NVC-modified polyacid on the bond strength of glass-ionomer cement to dentin was investigated. The mean data obtained from contact angle and bonding strength measurements were subjected to t test and 2-way ANOVA (α=.05). NVC-modified glass-ionomer cements showed significantly (P<.05) lower contact angles (46 degrees) and higher work of adhesion (W(A)=60.33 erg/cm(2)) in comparison to commercially available Fuji IX GP (57 degrees and W(A)=53.01 erg/cm(2)). The wettability of dentin surfaces conditioned with NVC-containing terpolymer was significantly higher (P<.05) (22 degrees, WA=73.77 erg/cm(2)) than dentin conditioned with GC dentin conditioner (29 degrees, W(A)=70.52 erg/cm(2)). The experimental cement also showed significantly higher values for shear bond strength to dentin (8.7 ±0.15 MPa after 1 month) when compared to the control group (8.4 ±0.13 MPa after 1 month). NVC-containing terpolymers may enhance the surface properties of GICs and increase their bond strength to the dentin. Furthermore, NVC-containing polyelectrolytes are better dentin conditioners than a commercially available dentin conditioner (GC dentin conditioner). Copyright © 2011 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Direct and transdentinal (indirect) antibacterial activity of commercially available dental gel formulations against Streptococcus mutans.

PubMed

Tüzüner, Tamer; Ulusoy, Ayça Tuba; Baygin, Ozgul; Yahyaoglu, Gorkem; Yalcin, Ilkay; Buruk, Kurtulus; Nicholson, John

2013-01-01

To evaluate the direct and transdentinal (indirect) agar diffusion antibacterial activity of different commercially available antibacterial dental gel formulations against Streptococcus mutans. The commercially available dental gel formulations were Corsodyl® (COG, 1% chlorhexidine), Cervitec® (CEG, 0.2% chlorhexidine + 0.2% sodium fluoride), Forever Bright® (FOB, aloe vera), Gengigel® (GEG, 0.2% hyaluronic acid), 35% phosphoric acid gel and distilled water (control). Direct agar diffusion was performed by isolating three wells from brain-heart infusion agar plates using sterile glass pipettes attached to a vacuum pump and adding 0.1 ml of the gels to each well. Transdentinal (indirect) agar diffusion was performed by applying gel to 0.2- and 0.5-mm-thick human dentin discs previously etched with phosphoric acid and rinsed with distilled water. Zones formed around the wells and the dentin discs were measured and analyzed using Kruskal-Wallis and Mann-Whitney U tests with Bonferroni correction (p < 0.01). Direct agar diffusion tests showed significant differences among all gel formulations (p < 0.01) except for COG and CEG (p > 0.01). COG and CEG exhibited higher antibacterial effects compared to FOB and GEG (p < 0.01) in both direct and transdentinal (indirect) testing procedures. GEG did not show any antimicrobial activity in transdentinal (indirect) testing. Commercially available dental gels inhibited S. mutans, which may indicate their potential as cavity disinfectants. Copyright © 2013 S. Karger AG, Basel.

Effect of sugar additives on stability of human serum albumin during vacuum foam drying and storage.

PubMed

Hajare, A A; More, H N; Pisal, S S

2011-11-01

No literature on the protein stabilization of human serum albumin (HSA) by vacuum foam drying (VFD) has been reported. The purpose of this study was to investigate the effect of sugar-additive systems on the stability of HSA by VFD. For the assessment, HSA was formulated with sucrose and mannitol, respectively, alone or in combination with stabilizers, which were vacuum foam dried and stored at 25C. Protein content of the resulting dried formulations was analyzed by Lowry method. Fourier-transform infrared spectroscopy (FT-IR) analysis of the HSA secondary structure showed apparent protein structure-stabilizing effects of the amorphous sugar and phosphate combination during the VFD. In particular, sucrose-sodium phosphate monobasic mixture provide an interesting alternative to pure saccharide formulations due to their high glass transition temperatures and their increased ability to maintain a low melting transition temperature in the presence of small amounts of water. Inhibition of the sucrose crystallization in solutions under vacuum resulted in highly amorphous sucrose. Changes in the endothermic melting transition suggested reduced sucrose molecular mobility with increase in the sodium phosphate ratio. The addition of phosphate salts to sugar systems has several interesting features that merit its consideration in formulations to protect dehydrated labile biomaterials. In conclusion, our data suggest that sucrose and phosphate as additives seem to protect HSA during VFD better than lyophilized products and also maintain its stability in the VFD state during storage.

A solvent-free coating-procedure for the improved preparation of cryostat sections in light microscope histochemistry.

PubMed

Fink, S

1992-01-01

A new technique is presented for the external stabilization of cryostat sections by spraying the specimen surfaces with an aqueous solution of poly(vinyl alcohol) before each sectioning stroke. The spray freezes upon the surface and forms a tough coating which facilitates subsequent sectioning and handling especially of difficult material. The sections are affixed upon cold glass slides covered with an improved formulation of pressure-sensitive adhesive. During further processing of the affixed sections, the PVA-coating and any surrounding supporting medium dissolve without traces in the first aqueous incubation or staining solution.

Compatibility of chewing gum excipients with the amino acid L-cysteine and stability of the active substance in directly compressed chewing gum formulation.

PubMed

Kartal, Alma; Björkqvist, Mikko; Lehto, Vesa-Pekka; Juppo, Anne Mari; Marvola, Martti; Sivén, Mia

2008-09-01

Using L-cysteine chewing gum to eliminate carcinogenic acetaldehyde in the mouth during smoking has recently been introduced. Besides its efficacy, optimal properties of the gum include stability of the formulation. However, only a limited number of studies exist on the compatibility of chewing gum excipients and stability of gum formulations. In this study we used the solid-state stability method, Fourier transform infrared spectroscopy and isothermal microcalorimetry to investigate the interactions between L-cysteine (as a free base or as a salt) and excipients commonly used in gum. These excipients include xylitol, sorbitol, magnesium stearate, Pharmagum S, Every T Toco and Smily 2 Toco. The influence of temperature and relative humidity during a three-month storage period on gum formulation was also studied. Cysteine alone was stable at 25 degrees C/60% RH and 45 degrees C/75% RH whether stored in open or closed glass ambers. As a component of binary mixtures, cysteine base remained stable at lower temperature and humidity but the salt form was incompatible with all the studied excipients. The results obtained with the different methods corresponded with each other. At high temperature and humidity, excipient incompatibility with both forms of cysteine was obvious. Such sensitivity to heat and humidity during storage was also seen in studies on gum formulations. It was also found that cysteine is sensitive to high pressure and increase in temperature induced by compression. The results suggest that the final product should be well protected from temperature and humidity and, for example, cooling process before compression should be considered.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alqathami, M; Lee, H; Ibbott, G

Purpose: To develop and evaluate novel radiochromic films for quality assurance in radiotherapy dosimetry. Materials and Methods: Novel radiochromic film compositions were formulated using leuco crystal violet (LCV) as a reporting system and tetrabromoethane as a free radical source. The film matrix used consisted of polyurethane polymer mixed with dibutyl phthalate plasticizer (20 wt%). The concentration of the radical initiator was kept constant at 10 wt% and the concentration of the LCV dye varied (1 and 2 wt%). To ensure uniform thickness of the film, its precursors were sandwiched between two pieces of glass separated by a 1 mm gapmore » between during the curing process. The films were cut into pieces and were irradiated with a 6 MV X-ray beam to selected doses. The change in optical density was measured using a flatbed scanner and a spectrophotometer. Results: The results showed that all film formulations exhibited a linear response with dose and an absorption maximum at ∼ 590 nm. The formulation with 2 wt% LCV was ∼ 30% more sensitive to dose than the formulation with 1 wt% LCV. Both films were very deformable. In addition, the radiochromic response of the film was found to bleach over a short period of time (few weeks) allowing the film to be reused for dose verification measurements. Conclusion: Both film formulations displayed excellent sensitivity and linearity to radiation dose and thus can be used for the 2D dosimetry of clinical megavoltage and kilovoltage X-ray beams. In addition, the thickness of the film could easily be increased allowing for their potential use as a deformable bolus material. However, thicker films would need more optimization of the manufacturing procedure to ensure consistent material uniformity and sensitivity are recommended.« less

Characterization of dynamics in complex lyophilized formulations: II. Analysis of density variations in terms of glass dynamics and comparisons with global mobility, fast dynamics, and Positron Annihilation Lifetime Spectroscopy (PALS)

PubMed Central

Chieng, Norman; Cicerone, Marcus T.; Zhong, Qin; Liu, Ming; Pikal, Michael J.

2013-01-01

Amorphous HES/disaccharide (trehalose or sucrose) formulations, with and without added polyols (glycerol and sorbitol) and disaccharide formulations of human growth hormone (hGH), were prepared by freeze drying and characterized with particular interest in methodology for using high precision density measurements to evaluate free volume changes and a focus on comparisons between “free volume” changes obtained from analysis of density data, fast dynamics (local mobility), and PALS characterization of “free volume” hole size. Density measurements were performed using a helium gas pycnometer, and fast dynamics was characterized using incoherent neutron scattering spectrometer. Addition of sucrose and trehalose to hGH decreases free volume in the system with sucrose marginally more effective than trehalose, consistent with superior pharmaceutical stability of sucrose hGH formulations well below Tg relative to trehalose. We find that density data may be analyzed in terms of free volume changes by evaluation of volume changes on mixing and calculation of apparent specific volumes from the densities. Addition of sucrose to HES decreases free volume, but the effect of trehalose is not detectable above experimental error. Addition of sorbitol or glycerol to HES/trehalose base formulations appears to significantly decrease free volume, consistent with the positive impact of such additions on pharmaceutical stability (i.e., degradation) in the glassy state. Free volume changes, evaluated from density data, fast dynamics amplitude of local motion, and PALS hole size data generally are in qualitative agreement for the HES/disaccharide systems studied. All predict decreasing molecular mobility as disaccharides are added to HES. Global mobility as measured by enthalpy relaxation times, increases as disaccharides, particularly sucrose, are added to HES. PMID:23623797

Interaction of Environmental Moisture with Powdered Green Tea Formulations: Relationship between Catechin Stability and Moisture-Induced Phase Transformations

PubMed Central

Ortiz, Julieta; Kestur, Umesh S.; Taylor, Lynne S.; Mauer, Lisa J.

2009-01-01

This study investigated the effect of phase transformations of amorphous and deliquescent ingredients on catechin stability in green tea powder formulations. Blends of amorphous green tea and crystalline sucrose, citric acid, and/or ascorbic acid were analyzed by X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), dynamic water vapor sorption, water activity measurements, and high-performance liquid chromatography (HPLC) after storage for up to 12 weeks at 0–75% relative humidity (RH) and 22 °C. The glass transition temperature (Tg) of green tea was reduced to below room temperature (<22 °C) at 68% RH. Dissolution of deliquescent ingredients commenced at RH values below deliquescence points in blends with amorphous green tea, and these blends had greater water uptake than predicted by an additive model of individual ingredient moisture sorption. Catechin degradation was affected by Tg of green tea powder and both dissolution and deliquescence of citric and ascorbic acids. PMID:19489621

A four-lens based plenoptic camera for depth measurements

NASA Astrophysics Data System (ADS)

Riou, Cécile; Deng, Zhiyuan; Colicchio, Bruno; Lauffenburger, Jean-Philippe; Kohler, Sophie; Haeberlé, Olivier; Cudel, Christophe

2015-04-01

In previous works, we have extended the principles of "variable homography", defined by Zhang and Greenspan, for measuring height of emergent fibers on glass and non-woven fabrics. This method has been defined for working with fabric samples progressing on a conveyor belt. Triggered acquisition of two successive images was needed to perform the 3D measurement. In this work, we have retained advantages of homography variable for measurements along Z axis, but we have reduced acquisitions number to a single one, by developing an acquisition device characterized by 4 lenses placed in front of a single image sensor. The idea is then to obtain four projected sub-images on a single CCD sensor. The device becomes a plenoptic or light field camera, capturing multiple views on the same image sensor. We have adapted the variable homography formulation for this device and we propose a new formulation to calculate a depth with plenoptic cameras. With these results, we have transformed our plenoptic camera in a depth camera and first results given are very promising.

Optimization of a polymer top electrode for inverted semitransparent organic solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Yinhua; Cheun, Hyeunseok; Choi, Seungkeun

We report on semitransparent organic solar cells using a single-layer blend based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the top electrode. The PEDOT:PSS blend was prepared by mixing a high-conductivity formulation of PEDOT:PSS (H.C. Starck CLEVIOS PH-1000) and another formulation of PEDOT:PSS (H.C. Starck CLEVIOS CPP 105D). The PEDOT:PSS blend yields good wetting properties on the hydrophobic surface of a blend of poly(3-hexylthiophene) (P3HT) with phenyl-C 61-butyric acid methyl ester (PC 60 BM), and shows a conductivity over 400 S cm -1. Semitransparent organic solar cells using the PEDOT:PSS blend as the top electrode with a structure of glass/ITO/ZnO/P3HT:PC 60BM/PEDOT:PSS-blend exhibited anmore » average power conversion efficiency of 2.4% estimated for 100 mW cm -2 AM 1.5G illumination.« less

Degree of conversion and hardness of two different systems of the Vitrebond™ glass ionomer cement light cured with blue LED.

PubMed

Calixto, Luiz Rafael; Tonetto, Mateus Rodrigues; Pinto, Shelon Cristina Souza; Barros, Erico Damasceno; Borges, Alvaro Henrique; Lima, Fabricio Viana Pereira; de Andrade, Marcelo Ferrarezi; Bandéca, Matheus Coelho

2013-03-01

This study investigated the physicochemical properties of the new formulation of the glass ionomer cements through hardness test and degree of conversion by infrared spectroscopy (FTIR). Forty specimens (n = 40) were made in a metallic mold (4 mm diameter x 2 mm thickness) with two resin-modified glass ionomer cements, Vitrebond™ and Vitrebond™ Plus (3M/ ESPE). Each specimen was light cured with blue LED with power density of 500 mW/cm(2) during 30 s. Immediately after light curing, 24h, 48h and 7 days the hardness and degree of conversion was determined. The Vickers hardness was performed by the MMT-3 microhardness tester using load of 50 gm force for 30 seconds. For degree of conversion, the specimens were pulverized, pressed with KBr and analyzed with FT-IR (Nexus 470). The statistical analysis of the data by ANOVA showed that the Vitrebond™ and Vitrebond™ Plus were no difference significant between the same storage times (p > 0.05). For degree of conversion, the Vitrebond™ and Vitrebond™ Plus were statistically different in all storage times after light curing. The Vitrebond™ showed higher values than Vitrebond™ Plus (p < 0.05). The performance of Vitrebond™ had greater results for degree of conversion than Vitrebond™ Plus. The correlation between hardness and degree of conversion was no evidence in this study.

Compatibility of butorphanol and droperidol in 0.9% sodium chloride injection.

PubMed

Chen, Fu-Chao; Fang, Bao-Xia; Li, Peng; Yang, Jin-Guo; Zhou, Ben-Hong

2013-03-15

The compatibility and stability of butorphanol tartrate and droperidol in polyvinyl chloride (PVC) bags and glass bottles stored at 4°C and 25°C for up to 15 days were studied. Admixtures were assessed initially and for 15 days after preparation in PVC bags and glass bottles using 0.9% sodium chloride injection as a diluent and stored at 4°C and 25°C. The initial drug concentrations were 0.08 mg/mL for butorphanol tartrate and 0.05 mg/mL for droperidol. Samples were withdrawn from each container immediately after preparation and at predetermined intervals (2, 4, 8, 24, 48, 72, 120, 168, 240, and 360 hours after preparation). The solutions were visually inspected for precipitation, cloudiness, and discoloration at each sampling interval. Drug concentrations were determined using a validated high-pressure liquid chromatography method. After 15 days of storage, all formulations tested retained >98% of the initial concentrations of both drugs. The drug mixtures were clear in appearance, and no color change or precipitation was observed. Throughout this period, pH values remained stable. Admixtures of butorphanol tartrate 0.08 mg/mL and droperidol 0.05 mg/mL in 0.9% sodium chloride injection were stable for at least 360 hours when stored in PVC bags or glass bottles at 4°C and 25°C and protected from light.

Stability of live attenuated rotavirus vaccine with selected preservatives and primary containers.

PubMed

Lal, Manjari; Jarrahian, Courtney; Zhu, Changcheng; Hosken, Nancy A; McClurkan, Chris L; Koelle, David M; Saxon, Eugene; Roehrig, Andrew; Zehrung, Darin; Chen, Dexiang

2016-05-11

Rotavirus infection, which can be prevented by vaccination, is responsible for a high burden of acute gastroenteritis disease in children, especially in low-income countries. An appropriate formulation, packaging, and delivery device for oral rotavirus vaccine has the potential to reduce the manufacturing cost of the vaccine and the logistical impact associated with introduction of a new vaccine, simplify the vaccination procedure, and ensure that the vaccine is safely and accurately delivered to children. Single-dose prefilled presentations can be easy to use; however, they are typically more expensive, can be a bottleneck during production, and occupy a greater volume per dose vis-à-vis supply chain storage and medical waste disposal, which is a challenge in low-resource settings. Multi-dose presentations used thus far have other issues, including increased wastage of vaccine and the need for separate delivery devices. In this study, the goals were to evaluate both the technical feasibility of using preservatives to develop a liquid multi-dose formulation and the primary packaging alternatives for orally delivered, liquid rotavirus vaccines. The feasibility evaluation included evaluation of commonly used preservatives for compatibility with rotavirus vaccines and stability testing of rotavirus vaccine in various primary containers, including Lameplast's plastic tubes, BD's oral dispenser version of Uniject™ (Uniject DP), rommelag's blow-fill-seal containers, and MEDInstill's multi-dose vial and pouch. These presentations were compared to a standard glass vial. The results showed that none of the preservatives tested were compatible with a live attenuated rotavirus vaccine because they had a detrimental effect on the viability of the virus. In the presence of preservatives, vaccine virus titers declined to undetectable levels within 1 month. The vaccine formulation without preservatives maintained a stability profile over 12 months in all primary containers that was similar to its profile in standard glass vials. This study demonstrates that there are multiple options for the primary container for rotavirus vaccines intended for oral delivery. Selection of an optimal primary container should take into consideration additional factors, including stability as well as cold chain volume, usability, cost, and manufacturing feasibility. Copyright © 2016. Published by Elsevier Ltd.

Impact of scaling on the nitric-glycolic acid flowsheet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, D.

Savannah River Remediation (SRR) is considering using glycolic acid as a replacement for formic acid in Sludge Receipt and Adjustment Tank (SRAT) processing in the Defense Waste Processing Facility (DWPF). Catalytic decomposition of formic acid is responsible for the generation of hydrogen, a potentially flammable gas, during processing. To prevent the formation of a flammable mixture in the offgas, an air purge is used to dilute the hydrogen concentration below the 60% of the Composite Lower Flammability Limit (CLFL). The offgas is continuously monitored for hydrogen using Gas Chromatographs (GCs). Since formic acid is much more volatile and toxic thanmore » glycolic acid, a formic acid spill would lead to the release of much larger quantities to the environment. Switching from formic acid to glycolic acid is expected to eliminate the hydrogen flammability hazard leading to lower air purges, thus downgrading of Safety Significant GCs to Process Support GCs, and minimizing the consequence of a glycolic acid tank leak in DWPF. Overall this leads to a reduction in process operation costs and an increase in safety margin. Experiments were completed at three different scales to demonstrate that the nitric-glycolic acid flowsheet scales from the 4-L lab scale to the 22-L bench scale and 220-L engineering scale. Ten process demonstrations of the sludge-only flowsheet for SRAT and Slurry Mix Evaporator (SME) cycles were performed using Sludge Batch 8 (SB8)-Tank 40 simulant. No Actinide Removal Process (ARP) product or strip effluent was added during the runs. Six experiments were completed at the 4-L scale, two experiments were completed at the 22-L scale, and two experiments were completed at the 220-L scale. Experiments completed at the 4-L scale (100 and 110% acid stoichiometry) were repeated at the 22-L and 220-L scale for scale comparisons.« less

Thiol-vinyl systems as shape memory polymers and novel two-stage reactive polymer systems

NASA Astrophysics Data System (ADS)

Nair, Devatha P.

2011-12-01

The focus of this research was to formulate, characterize and tailor the reaction methodologies and material properties of thiol-vinyl systems to develop novel polymer platforms for a range of engineering applications. Thiol-ene photopolymers were demonstrated to exhibit several advantageous characteristics for shape memory polymer systems for a range of biomedical applications. The thiol-ene shape memory polymer systems were tough and flexible as compared to the acrylic control systems with glass transition temperatures between 30 and 40 °C; ideal for actuation at body temperature. The thiol-ene polymers also exhibited excellent shape fixity and a rapid and distinct shape memory actuation response along with free strain recoveries of greater than 96% and constrained stress recoveries of 100%. Additionally, two-stage reactive thiol-acrylate systems were engineered as a polymer platform technology enabling two independent sets of polymer processing and material properties. There are distinct advantages to designing polymer systems that afford two distinct sets of material properties -- an intermediate polymer that would enable optimum handling and processing of the material (stage 1), while maintaining the ability to tune in different, final properties that enable the optimal functioning of the polymeric material (stage 2). To demonstrate the range of applicability of the two-stage reactive systems, three specific applications were demonstrated; shape memory polymers, lithographic impression materials, and optical materials. The thiol-acrylate reactions exhibit a wide range of application versatility due to the range of available thiol and acrylate monomers as well as reaction mechanisms such as Michael Addition reactions and free radical polymerizations. By designing a series of non-stoichiometeric thiol-acrylate systems, a polymer network is initially formed via a base catalyzed 'click' Michael addition reaction. This self-limiting reaction results in a Stage 1 polymer with excess acrylic functional groups within the network. At a later point in time, the photoinitiated, free radical polymerization of the excess acrylic functional groups results in a highly crosslinked, robust material system. By varying the monomers within the system as well as the stoichiometery of thiol to acrylate functional groups, the ability of the two-stage reactive systems to encompass a wide range of properties at the end of both the stage 1 and stage 2 polymerizations was demonstrated. The thiol-acrylate networks exhibited intermediate Stage 1 rubbery moduli and glass transition temperatures that range from 0.5 MPa and -10 ºC to 22 MPa and 22 ºC respectively. The same polymer networks can then attain glass transition temperatures that range from 5 ºC to 195 ºC and rubbery moduli of up to 200 MPa after the subsequent photocure stage. Two-stage reactive polymer composite systems were also formulated and characterized for thermomechanical and mechanical properties. Thermomechanical analysis showed that the fillers resulted in a significant increase in the modulus at both stage 1 and stage 2 polymerizations without a significant change in the glass transition temperatures (Tg). The two-stage reactive matrix composite formed with a hexafunctional acrylate matrix and 20 volume % silica particles showed a 125% increase in stage 1 modulus and 101% increase in stage 2 modulus, when compared with the modulus of the neat matrix. Finally, the two-stage reactive polymeric devices were formulated and designed as orthopedic suture anchors for arthroscopic surgeries and mechanically characterized. The Stage 1 device was designed to exhibit properties ideal for arthroscopic delivery and device placement with glass transition temperatures 25 -- 30 °C and rubbery moduli ˜ 95 MPa. The subsequent photopolymerization generated Stage 2 polymers designed to match the local bone environment with moduli ranging up to 2 GPa. Additionally, pull-out strengths of 140 N were demonstrated and are equivalent to the pull-strengths achieved by other commercially available suture anchors.

Distinctly Different Glass Transition Behaviors of Trehalose Mixed with Na2HPO 4 or NaH 2PO 4: Evidence for its Molecular Origin.

PubMed

Weng, Lindong; Elliott, Gloria D

2015-07-01

The present study is aimed at understanding how the interactions between sugar molecules and phosphate ions affect the glass transition temperature of their mixtures, and the implications for pharmaceutical formulations. The glass transition temperature (Tg) and the α-relaxation temperature (Tα) of dehydrated trehalose/sodium phosphate mixtures (monobasic or dibasic) were determined by differential scanning calorimetry and dynamic mechanical analysis, respectively. Molecular dynamics simulations were also conducted to investigate the microscopic interactions between sugar molecules and phosphate ions. The hydrogen-bonding characteristics and the self-aggregation features of these mixtures were quantified and compared. Thermal analysis measurements demonstrated that the addition of NaH2PO4 decreased both the glass transition temperature and the α-relaxation temperature of the dehydrated trehalose/NaH2PO4 mixture compared to trehalose alone while both Tg and Tα were increased by adding Na2HPO4 to pure trehalose. The hydrogen-bonding interactions between trehalose and HPO4(2-) were found to be stronger than both the trehalose-trehalose hydrogen bonds and those formed between trehalose and H2PO4(-). The HPO4(2-) ions also aggregated into smaller clusters than H2PO4(-) ions. The trehalose/Na2HPO4 mixture yielded a higher T g than pure trehalose because marginally self-aggregated HPO4(2-) ions established a strengthened hydrogen-bonding network with trehalose molecules. In contrast H2PO4(-) ions served only as plasticizers, resulting in a lower Tg of the mixtures than trehalose alone, creating large-sized ionic pockets, weakening interactions, and disrupting the original hydrogen-bonding network amongst trehalose molecules.

Development of a High Efficiency UVR/IRR Coverglass for Triple Junction Solar Cells

NASA Technical Reports Server (NTRS)

Russell, John; Jones, Glenn; Hall, James

2007-01-01

Cover glasses have been a necessary and integral part of space solar arrays since their inception. The main function of the cover glass is to protect the underlying solar cell from the harsh radiation environment of space. They are formed either from fused silica or specially formulated ceria doped glass types that are resistant to radiation damage, for example Pilkington's CMX, CMG, CMO. Solar cells have steadily increased in performance over the past years, from Silicon cells through textured Silicon cells to GaAs cells and the multijunction cells of today. The optimum coverglass solution for each of these cells has been different. The glass itself has also evolved. In some cases it has had its expansion coefficient matched to the cell substrate material, and in addition, added value has been derived from the application of thin film optical coatings to the coverglass. In the majority of cases this has taken the form of a single layer of MgF2 which acts as an antireflection coating. There are also conductive coatings to address electrostatic discharge issues (ESD) and Ultra Violet Reflective (UVR) and Infrared Reflective (IRR) coatings designed for thermal enhancement. Each type of coating can be applied singly or in combination. This paper describes a new type of UVR/IRR (or blue red reflector BRR) specifically designed for triple junction solar cells. For space applications, where radiation is the principal mechanism for removing heat from the satellite, it is the emittance and solar absorptance that primarily determine the temperature of the array. It is therefore essential that any coatings designed to have an effect on the temperature by reducing the solar absorption have a minimal effect on the overall emittance.

Distinctly Different Glass Transition Behaviors of Trehalose Mixed with Na2HPO4 or NaH2PO4: Evidence for its Molecular Origin

PubMed Central

Weng, Lindong; Elliott, Gloria D.

2015-01-01

Purpose The present study is aimed at understanding how the interactions between sugar molecules and phosphate ions affect the glass transition temperature of their mixtures, and the implications for pharmaceutical formulations. Methods The glass transition temperature (Tg) and the α-relaxation temperature (Tα) of dehydrated trehalose/sodium phosphate mixtures (monobasic or dibasic) were determined by differential scanning calorimetry and dynamic mechanical analysis, respectively. Molecular dynamics simulations were also conducted to investigate the microscopic interactions between sugar molecules and phosphate ions. The hydrogen-bonding characteristics and the self-aggregation features of these mixtures were quantified and compared. Results Thermal analysis measurements demonstrated that the addition of NaH2PO4 decreased both the glass transition temperature and the α-relaxation temperature of the dehydrated trehalose/NaH2PO4 mixture compared to trehalose alone while both Tg and Tα were increased by adding Na2HPO4 to pure trehalose. The hydrogen-bonding interactions between trehalose and HPO42− were found to be stronger than both the trehalose-trehalose hydrogen bonds and those formed between trehalose and H2PO4−. The HPO42− ions also aggregated into smaller clusters than H2PO4− ions. Conclusions The trehalose/Na2HPO4 mixture yielded a higher Tg than pure trehalose because marginally self-aggregated HPO42− ions established a strengthened hydrogen-bonding network with trehalose molecules. In contrast H2PO4− ions served only as plasticizers, resulting in a lower Tg of the mixtures than trehalose alone, creating large-sized ionic pockets, weakening interactions, and disrupting the original hydrogen-bonding network amongst trehalose molecules. PMID:25537342

Final Report - Testing of Optimized Bubbler Configuration for HLW Melter VSL-13R2950-1, Rev. 0, dated 6/12/2013

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, Albert A.; Pegg, I. L.; Callow, R. A.

2013-11-13

The principal objective of this work was to determine the glass production rate increase and ancillary effects of adding more bubbler outlets to the current WTP HLW melter baseline. This was accomplished through testing on the HLW Pilot Melter (DM1200) at VSL. The DM1200 unit was selected for these tests since it was used previously with several HLW waste streams including the four tank wastes proposed for initial processing at Hanford. This melter system was also used for the development and optimization of the present baseline WTP HLW bubbler configuration for the WTP HLW melter, as well as for MACTmore » testing for both HLW and LAW. Specific objectives of these tests were to: Conduct DM1200 melter testing with the baseline WTP bubbling configuration and as augmented with additional bubblers. Conduct DM1200 melter testing to differentiate the effects of total bubbler air flow and bubbler distribution on glass production rate and cold cap formation. Collect melter operating data including processing rate, temperatures at a variety of locations within the melter plenum space, melt pool temperature, glass melt density, and melter pressure with the baseline WTP bubbling configuration and as augmented with additional bubblers. Collect melter exhaust samples to compare particulate carryover for different bubbler configurations. Analyze all collected data to determine the effects of adding more bubblers to the WTP HLW melter to inform decisions regarding future lid re-designs. The work used a high aluminum HLW stream composition defined by ORP, for which an appropriate simulant and high waste loading glass formulation were developed and have been previously processed on the DM1200.« less

Synthesis and characterization of POSS-(PAA)8 star copolymers and GICs for dental applications.

PubMed

Zelmer, Christina; Wang, David K; Keen, Imelda; Hill, David J T; Symons, Anne L; Walsh, Laurence J; Rasoul, Firas

2016-04-01

To investigate the application of a new type of multiarm polymer resins in the formulation of Glass Ionic Cements. A series of star copolymers of t-butyl acrylate has been prepared by ATRP using a multiarm POSS-Br8 initiator. The resulting POSS-co-t-butyl acrylate star copolymers with eight arms were subsequently hydrolysed by trifluoroacetic acid to produce the corresponding POSS-co-acrylic acid star copolymers. All of the copolymers have been characterized by (1)H and (13)C NMR and FTIR spectroscopies and TGA/DSC. The as-prepared star copolymers were mixed with the glass powder from Fuji IX GP to produce the GIC samples for compression testing. The new type of multiarm polymer resins have been shown to have narrow molecular weight distributions and thermal properties of the acrylic acid copolymers are similar to that of poly(acrylic acid), with a two stage degradation profile involving transitions at ≈140°C and 250°C, corresponding to anhydride formation and loss of carbon dioxide, respectively. In aqueous solution the POSS-co-acrylic acid copolymers form aggregates with ≈33nm dimensions. When aqueous solutions of POSS-(PAA)8 are mixed with a glass powder, a rigid glass ionomer cement, GIC, is formed with a maximum compressive stress significantly greater than that for a linear PAA GIC of a comparable polymer molecular weight. Therefore, these POSS-(PAA)8 copolymers demonstrate the potential for the application of well characterized star copolymers in the future development of new GICs as dental materials. Copyright © 2016 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Fragility correlates thermodynamic and kinetic properties of glass forming liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reddy, C.Narayana; Viswanatha, R.; Chethana, B.K.

2015-03-15

Graphical abstract: The suggested new fragility parameter correlates viscosity and configurational entropy. - Highlights: • A new fragility function, F=ΔT/ΔC{sub p}×C{sub p}{sup l}/T{sub g} has been proposed. • A three parameter viscosity function using the new F reproduces Angell fragility plot. • A new ΔC{sub p} function is derived which directly relates Adam–Gibbs function with the fragility based viscosity function. - Abstract: In our earlier communication we proposed a simple fragility determining function, ([NBO]/V{sub m}{sup 3}T{sub g}), which we have now used to analyze several glass systems using available thermal data. A comparison with similar fragility determining function, ΔC{sub p}/C{submore » p}{sup l}, introduced by Chryssikos et al. in their investigation of lithium borate glasses has also been performed and found to be more convenient quantity for discussing fragilities. We now propose a new function which uses both ΔC{sub p} and ΔT and which gives a numerical fragility parameter, F whose value lies between 0 and 1 for glass forming liquids. F can be calculated through the use of measured thermal parameters ΔC{sub p}, C{sub p}{sup l}, T{sub g} and T{sub m}. Use of the new fragility values in reduced viscosity equation reproduces the whole range of viscosity curves of the Angell plot. The reduced viscosity equation can be directly compared with the Adam–Gibbs viscosity equation and a heat capacity function can be formulated which reproduces satisfactorily the ΔC{sub p} versus ln(T{sub r}) curves and hence the configurational entropy.« less

Crystallization of glass-forming liquids: Specific surface energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmelzer, Jürn W. P., E-mail: juern-w.schmelzer@uni-rostock.de; Abyzov, Alexander S.

2016-08-14

A generalization of the Stefan-Skapski-Turnbull relation for the melt-crystal specific interfacial energy is developed in terms of the generalized Gibbs approach extending its standard formulation to thermodynamic non-equilibrium states. With respect to crystal nucleation, this relation is required in order to determine the parameters of the critical crystal clusters being a prerequisite for the computation of the work of critical cluster formation. As one of its consequences, a relation for the dependence of the specific surface energy of critical clusters on temperature and pressure is derived applicable for small and moderate deviations from liquid-crystal macroscopic equilibrium states. Employing the Stefan-Skapski-Turnbullmore » relation, general expressions for the size and the work of formation of critical crystal clusters are formulated. The resulting expressions are much more complex as compared to the respective relations obtained via the classical Gibbs theory. Latter relations are retained as limiting cases of these more general expressions for moderate undercoolings. By this reason, the formulated, here, general relations for the specification of the critical cluster size and the work of critical cluster formation give a key for an appropriate interpretation of a variety of crystallization phenomena occurring at large undercoolings which cannot be understood in terms of the Gibbs’ classical treatment.« less

EFFECTS OF GAMMA IRRADIATION ON EPDM ELASTOMERS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, E.

Two formulations of EPDM elastomer, one substituting a UV stabilizer for the normal antioxidant in this polymer, and the other the normal formulation, were synthesized and samples of each were exposed to gamma irradiation in initially pure deuterium gas to compare their radiation stability. Stainless steel containers having rupture disks were designed for this task. After 130 MRad dose of cobalt-60 radiation in the SRNL Gamma Irradiation Facility, a significant amount of gas was created by radiolysis; however the composition indicated by mass spectroscopy indicated an unexpected increase in the total amount deuterium in both formulations. The irradiated samples retainedmore » their ductility in a bend test. No change of sample weight, dimensions, or density was observed. No change of the glass transition temperature as measured by dynamic mechanical analysis was observed, and most of the other dynamic mechanical properties remained unchanged. There appeared to be an increase in the storage modulus of the irradiated samples containing the UV stabilizer above the glass transition, which may indicate hardening of the material by radiation damage. Polymeric materials become damaged by exposure over time to ionizing radiation. Despite the limited lifetime, polymers have unique engineering material properties and polymers continue to be used in tritium handling systems. In tritium handling systems, polymers are employed mainly in joining applications such as valve sealing surfaces (eg. Stem tips, valve packing, and O-rings). Because of the continued need to employ polymers in tritium systems, over the past several years, programs at the Savannah River National Laboratory have been studying the effect of tritium on various polymers of interest. In these studies, samples of materials of interest to the SRS Tritium Facilities (ultra-high molecular weight polyethylene (UHMW-PE), polytetrafluoroethylene (PTFE, Teflon{reg_sign}), Vespel{reg_sign} polyimide, and the elastomer ethylene propylene diene monomer (EPDM)) have been exposed in closed containers to tritium gas initially at 1 atmosphere pressure. These studies have demonstrated the degradation of properties when exposed to tritium gas. Also, the radiolytic production of significant amounts of hydrogen has been observed for UHMW-PE and EPDM. The study documented in this report exposes two similar formulations of EPDM elastomer to gamma irradiation in a closed container backfilled with deuterium. Deuterium is chemically identical to protium and tritium, but allows the identification of protium that is radiolytically produced from the samples. The goal of this program is to compare and contrast the response of EPDM exposure to two different types of ionizing radiation in a similar chemical environment.« less

The impact of primary packaging on the quality of parenteral products.

PubMed

Solomun, Ljiljana; Ibric, Svetlana; Boltic, Zorana; Djuric, Zorica; Stupar, Biljana

2008-11-04

The unique approach in manufacturing of pharmaceutical dosage forms of active substances known to be unstable in aqueous solution is the introduction of lyophilization process. Nevertheless, these products must be reconstituted using the diluent from a separate container before application. The possible solution for this problem is the application of dual chamber vials comprising the freeze-dried product in a lower compartment of the vial and the solution for reconstitution in the upper chamber. The main issue in development of such product is the choice of contact packaging (rubber closures, glass vials and the container closure system as a whole). The most important parameter used for evaluation of the influence of contact material on product quality was the pH value. The results have shown that the type of vials (moulded or tubular glass) has no impact on pH shift of the solution for reconstitution (tested solution-TS), while significant differences in pH value of the TS were observed depending on the rubber closures formulation used (with some formulations, the pH shift during the test was 6.5-9.14). Benzyl alcohol assay during the tests remained unchanged. Integrity tests of the container closure system (CCS) have demonstrated the adequacy of the selected packaging system. The quality of the CCS of choice was confirmed in the course of stability studies, only parameters directly influenced by CCS being presented in this work: loss on drying and pH value. On the basis of these results, no changes in loss on drying were connected to CCS, and the pH value of the reconstituted solution remains unchanged in samples tested both ex-tempore and after in-use period of 48 h.

Support for HLW Direct Feed - Phase 2, VSL-15R3440-1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matlack, K. S.; Pegg, I.; Joseph, I.

This report describes work performed to develop and test new glass and feed formulations originating from a potential flow-sheet for the direct vitrification of High Level Waste (HLW) with minimal or no pretreatment. In the HLW direct feed option that is under consideration for early operations at the Hanford Tank Waste Treatment and Immobilization Plant (WTP), the pretreatment facility would be bypassed in order to support an earlier start-up of the vitrification facility. For HLW, this would mean that the ultrafiltration and caustic leaching operations that would otherwise have been performed in the pretreatment facility would either not be performedmore » or would be replaced by an interim pretreatment function (in-tank leaching and settling, for example). These changes would likely affect glass formulations and waste loadings and have impacts on the downstream vitrification operations. Modification of the pretreatment process may result in: (i) Higher aluminum contents if caustic leaching is not performed; (ii) Higher chromium contents if oxidative leaching is not performed; (iii) A higher fraction of supernate in the HLW feed resulting from the lower efficiency of in-tank washing; and (iv) A higher water content due to the likely lower effectiveness of in-tank settling compared to ultrafiltration. The HLW direct feed option has also been proposed as a potential route for treating HLW streams that contain the highest concentrations of fast-settling plutoniumcontaining particles, thereby avoiding some of the potential issues associated with such particles in the WTP Pretreatment facility [1]. In response, the work presented herein focuses on the impacts of increased supernate and water content on wastes from one of the candidate source tanks for the direct feed option that is high in plutonium.« less

Silicon, iron and titanium doped calcium phosphate-based glass reinforced biodegradable polyester composites as bone analogous materials

NASA Astrophysics Data System (ADS)

Shah Mohammadi, Maziar

Bone defects resulting from disease or traumatic injury is a major health care problem worldwide. Tissue engineering offers an alternative approach to repair and regenerate bone through the use of a cell-scaffold construct. The scaffold should be biodegradable, biocompatible, porous with an open pore structure, and should be able to withstand the applied forces. Phosphate-based glasses (PGs) may be used as reinforcing agents in degradable composites since their degradation can be predicted and controlled through their chemistry. This doctoral dissertation describes the development and evaluation of PGs reinforced biodegradable polyesters for intended applications in bone augmentation and regeneration. This research was divided into three main objectives: 1) Investigating the composition dependent properties of novel PG formulations by doping a sodium-free calcium phosphate-based glass with SiO2, Fe2O3, and TiO2. Accordingly, (50P2 O5-40CaO- xSiO2-(10-x)Fe2O3, where x = 10, 5 and 0 mol.%) and (50P2O5-40CaO-xSiO 2-(10-x)TiO2 where x = 10, 7, 5, 3 and 0 mol.%) formulations were developed and characterised. SiO2 incorporation led to increased solubility, ion release, pH reduction, as well as hydrophilicity, surface energy, and surface polarity. In contrast, doping with Fe2O 3 or TiO2 resulted in more durable glasses, and improved cell attachment and viability. It was hypothesised that the presence of SiO 2 in the TiO2-doped formulations could up-regulate the ionic release from the PG leading to higher alkaline phosphatase activity of MC3T3-E1 cells. 2) Incorporating Si, Fe, and Ti doped PGs as fillers, either as particulates (PGPs) or fibres (PGFs), into biodegradable polyesters (polycaprolactone (PCL) and semi-crystalline and amorphous poly(lactic acid) (PLA and PDLLA)) with the aim of developing degradable bone analogous composites. It was found that PG composition and geometry dictated the weight loss, ionic release, and mechanical properties of the composites. It was also hypothesised that a potential reaction between Si and the ester bond led to the formation of carboxylate by-products resulting in a lower molecular weight polymer, thus affecting the mechanical properties of the composites. Cytocompatibility assessment with MC3T3-E1 pre-osteoblasts showed that these composites were cytocompatible, and cell alignment along the PGFs was observed possibly due to their favourable ionic release properties. 3) Investigating the solid-state foaming using carbon dioxide (CO 2) of PDLLA-PGP composites with up to 30 vol.% filler content. While PDLLA foams resulted in 92% porosity, the porosity of the composites ranged between 79 and 91% which decreased with PGP content. In addition, a reduction in pore size was observed with increasing PGP content; however, the pore size maintained its range of 200-500 μm in all composite foams, suitable for bone tissue engineering applications. The percentage of open pores increased significantly with PGP content (up to 78% at 30 vol.% PGP). Compressive strength and modulus of PDLLA-PGP foams showed up to approximately 3-fold increase at 30 vol.% PGP content compared to neat PDLLA foams.

How do silanes affect the lubricating properties of cationic double chain surfactant on silica surfaces?

PubMed

Beauvais, Muriel; Serreau, Laurence; Heitz, Caroline; Barthel, Etienne

2009-03-01

The effect of an aminosilane on the lubricant properties of a C(18) double-chained cationic surfactant has been investigated in the context of glass fiber forming process. The surfactant adsorption was studied on silica by Fourier transform infrared (FT-IR) spectroscopy in the attenuated total reflexion (ATR) mode as a function of the aminosilane concentration in an organic water based formulation (sizing) used to coat the glass fibers during the process. A reciprocating ball-on-plate tribometer was used to compare friction properties of silica in contact with the aminosilane-surfactant mixture and in presence of each component of the sizing. Surface forces were measured between silica and an atomic force microscope (AFM) silicon nitride tip in the sizing and in the pure cationic surfactant solution. The aminosilane on its own has no lubricant property and reduces or even suppresses the cationic surfactant adsorption on silica. However, the silica-silica contact is lubricated even if the infrared spectroscopy does not detect any surfactant adsorption. The repeated contacts and shear due to the friction experiment itself induce accumulation, organization and compactness of surfactant bilayers.

A hidden variable in shear transformation zone volume versus Poisson's ratio relation in metallic glasses

NASA Astrophysics Data System (ADS)

Kim, S. Y.; Oh, H. S.; Park, E. S.

2017-10-01

Herein, we elucidate a hidden variable in a shear transformation zone (STZ) volume (Ω) versus Poisson's ratio (ν) relation and clarify the correlation between STZ characteristics and the plasticity of metallic glasses (MGs). On the basis of cooperative shear model and atomic stress theories, we carefully formulate Ω as a function of molar volume (Vm) and ν. The twofold trend in Ω and ν is attributed to a relatively large variation of Vm as compared to that of ν as well as an inverse relation between Vm and ν. Indeed, the derived equation reveals that the number of atoms in an STZ instead of Ω is a microstructural characteristic which has a close relationship with plasticity since it reflects the preference of atomistic behaviors between cooperative shearing and the generation of volume strain fluctuation under stress. The results would deepen our understanding of the correlation between microscopic behaviors (STZ activation) and macroscopic properties (plasticity) in MGs and enable a quantitative approach in associating various STZ-related macroscopic behaviors with intrinsic properties of MGs.

An Experimental Evaluation of Mechanical Properties of Hybrid Reinforcements

NASA Astrophysics Data System (ADS)

Sai Kumar, A.; Ganesan, G.; Karthikeyan, K.

2017-07-01

This paper presents the mechanical properties of unidirectional hybrid reinforcements formed from continuous fibres impregnated with a fibre binding material which are used for reinforcing the concrete. Recently FRP (Fibre Reinforced Polymer) manufacturers and suppliers have been increased all over the world because of the superior performance of FRP products in the construction industry. Its non-corrosive nature has turned the attention of many researchers to make several studies on different type of FRP products. Through a vast research, several standards also have been formulated. In this regard a new combination of FRP materials is tried in this paper and its properties have been derived. Carbon fibre and glass fibres fuse in this study to form a new hybrid rebar. The design properties such as tensile strength, tensile modulus, and compressive strength have been studied as per ASTM standards and it has been identified that the Hybrid rebar show a superior performance in comparison with GFRP (Glass FRP) and Steel rebars. This extraordinary performance of hybrid composite material increases the extensive engineering applications such as transport industry, aeronautics, naval, automotive industries.

Ferulic Acid-Based Polymers with Glycol Functionality as a Versatile Platform for Topical Applications.

PubMed

Ouimet, Michelle A; Faig, Jonathan J; Yu, Weiling; Uhrich, Kathryn E

2015-09-14

Ferulic acid-based polymers with aliphatic linkages have been previously synthesized via solution polymerization methods, yet they feature relatively slow ferulic acid release rates (∼11 months to 100% completion). To achieve a more rapid release rate as required in skin care formulations, ferulic acid-based polymers with ethylene glycol linkers were prepared to increase hydrophilicity and, in turn, increase ferulic acid release rates. The polymers were characterized using nuclear magnetic resonance and Fourier transform infrared spectroscopies to confirm chemical composition. The molecular weights, thermal properties (e.g., glass transition temperature), and contact angles were also obtained and the polymers compared. Polymer glass transition temperature was observed to decrease with increasing linker molecule length, whereas increasing oxygen content decreased polymer contact angle. The polymers' chemical structures and physical properties were shown to influence ferulic acid release rates and antioxidant activity. In all polymers, ferulic acid release was achieved with no bioactive decomposition. These polymers demonstrate the ability to strategically release ferulic acid at rates and concentrations relevant for topical applications such as skin care products.

Statistical Mechanical Theory of Penetrant Diffusion in Polymer Melts and Glasses

NASA Astrophysics Data System (ADS)

Zhang, Rui; Schweizer, Kenneth

We generalize our force-level, self-consistent nonlinear Langevin equation theory of activated diffusion of a dilute spherical penetrant in hard sphere fluids to predict the long-time diffusivity of molecular penetrants in supercooled polymer liquids and non-aging glasses. Chemical complexity is treated using an a priori mapping to a temperature-dependent hard sphere mixture model where polymers are disconnected into effective spheres based on the Kuhn length as the relevant coarse graining scale. A key parameter for mobility is the penetrant to polymer segment diameter ratio, R. Our calculations agree well with experimental measurements for a wide range of temperatures, penetrant sizes (from gas molecules with R ~0.3 to aromatic molecules with R ~1) and diverse amorphous polymers, over 10 decades variation of penetrant diffusivity. Structural parameter transferability is good. We have also formulated a theory at finite penetrant loading for the coupled penetrant-polymer dynamics in chemically (nearly) matched mixtures (e.g., toluene-polystyrene) which captures well the increase of penetrant diffusivity and decrease of polymer matrix vitrification temperature with increasing loading.

Statistical Mechanical Theory of Coupled Slow Dynamics in Glassy Polymer-Molecule Mixtures

NASA Astrophysics Data System (ADS)

Zhang, Rui; Schweizer, Kenneth

The microscopic Elastically Collective Nonlinear Langevin Equation theory of activated relaxation in one-component supercooled liquids and glasses is generalized to polymer-molecule mixtures. The key idea is to account for dynamic coupling between molecule and polymer segment motion. For describing the molecule hopping event, a temporal casuality condition is formulated to self-consistently determine a dimensionless degree of matrix distortion relative to the molecule jump distance based on the concept of coupled dynamic free energies. Implementation for real materials employs an established Kuhn sphere model of the polymer liquid and a quantitative mapping to a hard particle reference system guided by the experimental equation-of-state. The theory makes predictions for the mixture dynamic shear modulus, activated relaxation time and diffusivity of both species, and mixture glass transition temperature as a function of molecule-Kuhn segment size ratio and attraction strength, composition and temperature. Model calculations illustrate the dynamical behavior in three distinct mixture regimes (fully miscible, bridging, clustering) controlled by the molecule-polymer interaction or chi-parameter. Applications to specific experimental systems will be discussed.

Letter Report: LAW Simulant Development for Cast Stone Screening Test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Russell, Renee L.; Westsik, Joseph H.; Swanberg, David J.

2013-03-27

More than 56 million gallons of radioactive and hazardous waste are stored in 177 underground storage tanks at the U.S. Department of Energy’s (DOE’s) Hanford Site in southeastern Washington State. The Hanford Tank Waste Treatment and Immobilization Plant (WTP) is being constructed to treat the wastes and immobilize them in a glass waste form. The WTP includes a pretreatment facility to separate the wastes into a small volume of high-level waste (HLW) containing most of the radioactivity and a larger volume of low-activity waste (LAW) containing most of the nonradioactive chemicals. The HLW will be converted to glass in themore » HLW vitrification facility for ultimate disposal at an offsite federal repository. At least a portion (~35%) of the LAW will be converted to glass in the LAW vitrification facility and will be disposed of onsite at the Integrated Disposal Facility (IDF). The pretreatment and HLW vitrification facilities will have the capacity to treat and immobilize the wastes destined for each facility. However, a second facility will be needed for the expected volume of additional LAW requiring immobilization. A cementitious waste form known as Cast Stone is being considered to provide the required additional LAW immobilization capacity. The Cast Stone waste form must be acceptable for disposal in the IDF. The Cast Stone waste form and immobilization process must be tested to demonstrate that the final Cast Stone waste form can comply with waste acceptance criteria for the IDF disposal facility and that the immobilization processes can be controlled to consistently provide an acceptable waste form product. Further, the waste form must be tested to provide the technical basis for understanding the long term performance of the waste form in the IDF disposal environment. These waste form performance data are needed to support risk assessment and performance assessment (PA) analyses of the long-term environmental impact of the waste disposal in the IDF. A testing program was developed in fiscal year (FY) 2012 describing in some detail the work needed to develop and qualify Cast Stone as a waste form for the solidification of Hanford LAW (Westsik et al. 2012). Included within Westsik et al. (2012) is a section on the near-term needs to address Tri-Party Agreement Milestone M-062-40ZZ. The objectives of the testing program to be conducted in FY 2013 and FY 2014 are to: • Determine an acceptable formulation for the LAW Cast Stone waste form. • Evaluate sources of dry materials for preparing the LAW Cast Stone. • Demonstrate the robustness of the Cast Stone waste form for a range of LAW compositions. • Demonstrate the robustness of the formulation for variability in the Cast Stone process. • Provide Cast Stone contaminant release data for PA and risk assessment evaluations. The first step in determining an acceptable formulation for the LAW Cast Stone waste form is to conduct screening tests to examine expected ranges in pretreated LAW composition, waste stream concentrations, dry-materials sources, and mix ratios of waste feed to dry blend. A statistically designed test matrix will be used to evaluate the effects of these key parameters on the properties of the Cast Stone as it is initially prepared and after curing. The second phase of testing will focus on selection of a baseline Cast Stone formulation for LAW and demonstrating that Cast Stone can meet expected waste form requirements for disposal in the IDF. It is expected that this testing will use the results of the screening tests to define a smaller suite of tests to refine the composition of the baseline Cast Stone formulation (e.g. waste concentration, water to dry mix ratio, waste loading).« less

Properties of a proline-containing glass ionomer dental cement.

PubMed

Ansari, Sahar; Moshaverinia, Maryam; Roohpour, Nima; Chee, Winston W L; Schricker, Scott R; Moshaverinia, Alireza

2013-11-01

Proline-containing glass ionomers are promising fast-set dental restorative materials with superior mechanical properties; however, little information is available on other physical properties of this type of glass ionomer. The objectives of this study were to synthesize and characterize a polyacrylic acid terpolymer containing proline derivative (PD) and to investigate the physical properties of this glass ionomer cement (GIC) and its cytotoxicity in vitro. A terpolymer of AA (acrylic acid), IA (itaconic acid), and proline derivative (MP) with an 8:1:1 molar ratio was synthesized and characterized. Experimental GIC specimens were made from the synthetized terpolymer with Fuji IX (GC America, Alsip, Ill) commercial glass ionomer powder as recommended by the manufacturer. Specimens were mixed and fabricated at room temperature and were conditioned in distilled water at 37°C for 1 day and 1 week. Vickers hardness was determined with a microhardness tester. The water sorption characteristics and fluoride releasing properties of the specimens were investigated. The in vitro cytotoxicity of the experimental glass ionomer was assessed by evaluating the C2C12 cell metabolism with methyltetrazolium (MTT) assay. Commercial Fuji IX was used as a control for comparison. The data obtained for the experimental GIC (PD) were compared with the control group by using 1- and 2-way ANOVA and the Tukey multiple range test at α=.05. Proline-modified GIC (PD) exhibited significantly higher surface hardness values (Vickers hardness number [VHN] 58 ±6.1) in comparison to Fuji IX GIC (VHN 47 ±5.3) after 1 week of maturation. Statistical analysis of data showed that the water sorption properties of the experimental cement (PD) were significantly greater than those of the control group (P<.05). The experimental GIC showed a significant increase in the amounts of initial fluoride release (P<.05) with continued fluoride release from the bulk of the material. The experimental group showed slightly reduced cell metabolism and cell number in comparison to the control group. However, the results were not statistically different (P>.05). An amino acid-containing GIC had better surface hardness properties than commercial Fuji IX GIC. This formulation of fast-set glass ionomer showed increased water sorption without adversely affecting the amount of fluoride release. Considering its biocompatibility, this material shows promise not only as a dental restorative material but also as a bone cement with low cytotoxicity. Copyright © 2013 Editorial Council for the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Microscopic Theory for the Role of Attractive Forces in the Dynamics of Supercooled Liquids.

PubMed

Dell, Zachary E; Schweizer, Kenneth S

2015-11-13

We formulate a microscopic, no adjustable parameter, theory of activated relaxation in supercooled liquids directly in terms of the repulsive and attractive forces within the framework of pair correlations. Under isochoric conditions, attractive forces can nonperturbatively modify slow dynamics, but at high enough density their influence vanishes. Under isobaric conditions, attractive forces play a minor role. High temperature apparent Arrhenius behavior and density-temperature scaling are predicted. Our results are consistent with recent isochoric simulations and isobaric experiments on a deeply supercooled molecular liquid. The approach can be generalized to treat colloidal gelation and glass melting, and other soft matter slow dynamics problems.

Literature Review: An Overview of Epoxy Resin Syntactic Foams with Glass Microballoons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keller, Jennie

2014-03-12

Syntactic foams are an important category of composite materials that have abundant applications in a wide variety of fields. The bulk phase of syntactic foams is a three-part epoxy resin formulation that consists of a base resin, a curative (curing agent) and a modifier (diluent and/or accelerator) [12]. These thermoset materials [12] are used frequently for their thermal stability [9], low moisture absorption and high compressive strength [10]. The characteristic feature of a syntactic foam is a network of beads that forms pores within the epoxy matrix [3]. In this review, hollow glass beads (known as glass microballoons) are considered,more » however, solid beads or microballoons made from materials such as ceramic, polymer or metal can also be used [3M, Peter]. The network of hollow beads forms a closed-cell foam; the term closed-cell comes from the fact that the microspheres used in the resin matrix are completely closed and filled with gas (termed hollow). In contrast, the microspheres used in open-cell foams are either not completely closed or broken so that matrix material can fill the spheres [11]. Although closed foams have been found to possess higher densities than open cell foams, their rigid structures give them superior mechanical properties [12]. Past research has extensively studied the effects that changing the volume fraction of microballoons to epoxy will have on the resulting syntactic foam [3,4,9]. In addition, published literature also explores how the microballoon wall thickness affects the final product [4,9,10]. Findings detail that indeed both the mechanical and some thermal properties of syntactic foams can be tailored to a specific application by varying either the volume fraction or the wall thickness of the microballoons used [10]. The major trends in syntactic foam research show that microballoon volume fraction has an inversely proportionate relationship to dynamic properties, while microballoon wall thickness is proportional to those same properties [3,4,9,10]. The glass transition temperature has a proportional relationship to the volume fraction of microballoons used, however, there is limited research that supports correlations between other thermal variables and microballoons specifications. In fact, very little experimental data exists to relate thermal conductivity and volume fraction or wall thickness of microballoons [5]. This review proposes that thermal conductivity should be a topic of interest for future researchers because of how frequently syntactic foams are used in insulating applications. This paper will explore three aspects pertaining to epoxy resin syntactic foams with glass microballoons: the immense range of applications that syntactic foams are used for, the materials and fabrication techniques most commonly used, and lastly the results from characterization of syntactic foams with varying microballoon volume fractions and wall thicknesses. In addition to varying microballoon parameters, it is also possible to change the base, accelerator and curing agent used in the epoxy formulation. For simplicity, this paper will focus on a very common combination of materials produced by the Dow Chemical Company®.« less

Hypoxia-mimicking bioactive glass regenerative effects on dental stem cells

NASA Astrophysics Data System (ADS)

Noor, Siti Noor Fazliah Mohd; Azevedo, Maria; Mohamad, Hasmaliza; Autefage, Hélène

2016-12-01

Vascularization is an important aspect of tissue regeneration. Hypoxia, low oxygen concentration, is a known stimulus for the release of vascular endothelial growth factors (VEGF) which play important roles in vascularization. The current study aimed to assess the effect of a cobalt-containing bioactive glass (BG) in stimulating hypoxia and promoting vascularization. To incorporate cobalt into BG, 1 mol% of calcium was substituting with cobalt, and this formulation was compared to the one without cobalt. Both BGs were processed via melt-derived method. The BG powders with particle size less than 38 µm were incubated with cell culture medium for 4 hours at 37°C on continuous rolling, and then the medium was filtered using 0.22 µm syringe filters. Prior to use, the BG-conditioned media were supplemented with 10% (v/v) fetal bovine serum and 1% (v/v) antibiotic-antimycotic, and were allowed to equilibrate overnight inside a CO2 incubator. The conditioned media were used on human dental stem cells (stem cells from permanent (DPSC) and deciduous (SHED) teeth) and assessed for their capacity to stimulate the release of angiogenic factors from the cells. The results showed that cobalt ions were released from the cobalt-containing BG, following partial dissolution of the glasses in cell culture medium, and promoted VEGF release from the cells. In conclusion, the incorporation of cobalt in BG may have potential to be used for tissue regeneration by promoting vascularization through the activation of hypoxia pathway and the release of VEGF.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aytug, Tolga; Lupini, Andrew R.; Jellison, Gerald E.

The design of multifunctional coatings impact impact the performance of many optical systems and components. Such coatings should be mechanically robust, and combine user-defined optical and wetting functions with scalable fabrication formulations. By taking cues from the properties of some natural biological structures, we report here the formation of low-refractive index antireflective glass films that embody omni-directional optical properties over a wide range of wavelengths, while also possessing specific wetting capabilities. The coatings comprise an interconnected network of nanoscale pores surrounded by a nanostructured silica framework. These structures result from a novel fabrication method that utilizes metastable spinodal phase separationmore » in glass-based materials. The approach not only enables design of surface microstructures with graded-index antireflection characteristics, where the surface reflection is suppressed through optical impedance matching between interfaces, but also facilitates self-cleaning ability through modification of the surface chemistry. Based on near complete elimination of Fresnel reflections (yielding >95% transmission through a single-side coated glass) and corresponding increase in broadband transmission, the fabricated nanostructured surfaces are found to promote a general and an invaluable ~3–7% relative increase in current output of multiple direct/indirect bandgap photovoltaic cells. Moreover, these antireflective surfaces also demonstrate superior resistance against mechanical wear and abrasion. Unlike conventional counterparts, the present antireflective coatings are essentially monolithic, enabling simultaneous realization of graded index anti-reflectivity, self-cleaning capability, and mechanical stability within the same surface. Moreover, the concept represents a fundamental basis for development of advanced coated optical quality products, especially where environmental exposure is required.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cozzi, Alex D.; McCabe, Daniel J.

The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream (LAW Melter Off-Gas Condensate) from the off-gas system. The baseline plan for disposition of this stream during full WTP operations is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility. However, during the Direct Feed LAW (DFLAW) scenario, planned disposition of this stream is to evaporate it in a new evaporator in the Effluent Management Facility (EMF) and then return it to themore » LAW melter. It is important to understand the composition of the effluents from the melter and new evaporator so that the disposition of these streams can be accurately planned and accommodated. Furthermore, alternate disposition of this stream would eliminate recycling of problematic components, and would enable less integrated operation of the LAW melter and the Pretreatment Facilities. Alternate disposition would also eliminate this stream from recycling within WTP when it begins operations and would decrease the LAW vitrification mission duration and quantity of glass waste. This LAW Melter Off-Gas Condensate stream will contain components that are volatile at melter temperatures and are problematic for the glass waste form, such as halides and sulfate, along with entrained, volatile, and semi-volatile metals, such as Hg, As, and Se. Because this stream will recycle within WTP, these components accumulate in the Melter Condensate stream, exacerbating their impact on the number of LAW glass containers that must be produced. Diverting the stream reduces the halides and sulfate that get recycled to the melter, and is a key objective of this work. This overall program examines the potential treatment and immobilization of this stream to enable alternative disposal. The objective of earlier tasks was to formulate and prepare a simulant of the LAW Melter Off-gas Condensate expected during DFLAW operations and use it in evaporator testing to predict the composition of the effluents from the Effluent Management Facility (EMF) evaporator to aid in planning for their disposition. The objective of this task was to test immobilization options for this evaporator bottoms aqueous stream. This document describes the method used to formulate a simulant of this EMF evaporator bottoms stream, immobilize it, and determine if the immobilized waste forms meet disposal criteria.« less

Bioactive glass for dentin remineralization: A systematic review.

PubMed

Fernando, Delihta; Attik, Nina; Pradelle-Plasse, Nelly; Jackson, Phil; Grosgogeat, Brigitte; Colon, Pierre

2017-07-01

Strategies to achieve dentin remineralization is at present an important target of restorative dentistry. Remineralization of dentin by a bioactive material is complete only when the tissue regains its functionality. This is achieved when there is adequate apatite formation which most importantly translates into improved mechanical properties of dentin as a result of intrafibrillar mineralization. Bioactive glass (BAG) is a well-known implant material for bone regeneration and is proven to have excellent ability of apatite formation. Hence, recent studies have proposed BAGs as one of the most desired materials for remineralization of dentin. Therefore the aim of this systematic review was to scope the evidence of bioactive glass to remineralize dentin. The following research question was formulated: "Is there strong evidence for bioactive glass to remineralize dentin?" Three databases (Web of science, PubMed and Science direct) were scanned independently following PRISMA guidelines. Inclusion and exclusion criteria were set to identify relevant articles based on title and abstract screening. Finally, potentially relevant articles were downloaded and the full text was scrutinized to select the articles included in this review. The first phase of search returned 303 articles. A total of 19 papers with full text were scrutinized for inclusion, of which 3 papers were chosen for the final synthesis. All three studies confirm that BAG treatment leads to enhanced apatite formation in dentin. Only 1 of the 3 studies has reported the mechanical properties of dentin after BAG treatment and it revealed that the Young's modulus and flexural bend strength of BAG treated dentin were much lower than natural dentin even though they had similar apatite content. This review highlights the importance of assessing the mechanical properties of dentin alongside to the newly formed apatite content in order to prove BAGs efficiency to remineralize this tissue. Though studies have confirmed that BAGs stimulate excellent apatite formation in dentin, it should be concluded that there isn't sufficient evidence for bioactive glass to effectively remineralize this tissue as the mechanical properties of the BAG treated dentin haven't been well explored. Copyright © 2017 Elsevier B.V. All rights reserved.

The influence of different screw concepts while processing fibre reinforced thermoplastics with the concept of inline-compounding on an injection moulding machine

NASA Astrophysics Data System (ADS)

Moritzer, E.; Müller, E.; Kleeschulte, R.

2014-05-01

Today, the global market poses major challenges for industrial product development. Complexity, the wide range of variants, flexibility and individuality are just some of the features that products have to fulfil. Product series additionally have shorter and shorter lifetimes. Because of their high capacity for adaptation, polymers are increasingly able to substitute traditional materials such as wood, glass and metals in various fields of application [1]. But polymers can only substitute other materials if they are optimally suited to the applications in question. Hence, product-specific material development is becoming increasingly important [2]. The problem is that the traditional development process for new polymer formulations is much too complex, too slow and therefore too expensive. Product-specific material development is thus out of the question for most processors. Integrating the compounding step in the injection moulding process would lead to a more efficient and faster development process for a new polymer formulation, providing an opportunity to create new product-specific materials. This process is called inline-compounding on an injection moulding machine. In order to develop this innovative formulation concept, with the focus on fibre reinforced thermoplastics, different screw-concepts are compared with regard to the resultant performance characteristics in the part, such as mechanical properties and fibre length distribution.

Stable amorphous binary systems of glipizide and atorvastatin powders with enhanced dissolution profiles: formulation and characterization.

PubMed

Renuka; Singh, Sachin Kumar; Gulati, Monica; Narang, Rakesh

2017-02-01

The aim of this study was to enhance the dissolution profile of the combination of glipizide and atorvastatin used for simultaneous treatment of hyperglycemia and hyperlipidemia. The strategy to formulate coamorphous glipizide-atorvastatin binary mixture was explored to achieve enhancement in dissolution. The coamorphous glipizide-atorvastatin mixtures (1:1, 1:2 and 2:1) were prepared by cryomilling and characterized with respect to their dissolution profiles, preformulation parameters and physical stability. Amorphization was found to be possible by cryomilling at various tried ratios of the two drugs. The data obtained from glass transition temperatures and from Raman spectroscopy point toward practically no interaction between the two drugs. The dissolution studies revealed the highest enhancement in dissolution profiles of cryomilled coamorphous mixtures containing GPZ:ATV in ratios 1:1 (B-5) and 2:1 (B-7). These two mixtures were, therefore, subjected to studies for the evaluation of precompression parameters in order to find their amenability to satisfactory compression into tablet dosage form. The selected formulation was found to be stable when subjected to accelerated stability testing at 40°. C/75% RH for six months as per ICH guidelines. Based on all these studies, it was concluded that GPZ:ATV (1:1) combination may be able to provide an effective therapy for the comorbidities of hyperglycemia and hyperlipidemia.

Compositional design and optimization of dentin adhesive with neutralization capability.

PubMed

Song, Linyong; Ye, Qiang; Ge, Xueping; Spencer, Paulette

2015-09-01

The objective of this work was to investigate the polymerization behavior, neutralization capability, and mechanical properties of dentin adhesive formulations with the addition of the tertiary amine co-monomer, 2-N-morpholinoethyl methacrylate (MEMA). A co-monomer mixture based on HEMA/BisGMA (45/55, w/w) was used as a control adhesive. Compared with the control formulation, the MEMA-containing adhesive formulations were characterized comprehensively with regard to water miscibility of liquid resin, water sorption and solubility of cured polymer, real-time photopolymerization kinetics, dynamic mechanical analysis (DMA), and modulated differential scanning calorimetry (MDSC). The neutralization capacity was characterized by monitoring the pH shift of 1mM lactic acid (LA) solution, in which the adhesive polymers were soaked. With increasing MEMA concentrations, experimental copolymers showed higher water sorption, lower glass transition temperature and lower crosslinking density compared to the control. The pH values of LA solution gradually increased from 3.5 to about 6.0-6.5 after 90 days. With the increase in crosslinking density of the copolymers, the neutralization rate was depressed. The optimal MEMA concentration was between 20 and 40 wt%. As compared to the control, the results indicated that the MEMA-functionalized copolymer showed neutralization capability. The crosslinking density of the copolymer networks influenced the neutralization rate. Copyright © 2015 Elsevier Ltd. All rights reserved.