Real time monitoring of powder blend bulk density for coupled feed-forward/feed-back control of a continuous direct compaction tablet manufacturing process.

PubMed

Singh, Ravendra; Román-Ospino, Andrés D; Romañach, Rodolfo J; Ierapetritou, Marianthi; Ramachandran, Rohit

2015-11-10

The pharmaceutical industry is strictly regulated, where precise and accurate control of the end product quality is necessary to ensure the effectiveness of the drug products. For such control, the process and raw materials variability ideally need to be fed-forward in real time into an automatic control system so that a proactive action can be taken before it can affect the end product quality. Variations in raw material properties (e.g., particle size), feeder hopper level, amount of lubrication, milling and blending action, applied shear in different processing stages can affect the blend density significantly and thereby tablet weight, hardness and dissolution. Therefore, real time monitoring of powder bulk density variability and its incorporation into the automatic control system so that its effect can be mitigated proactively and efficiently is highly desired. However, real time monitoring of powder bulk density is still a challenging task because of different level of complexities. In this work, powder bulk density which has a significant effect on the critical quality attributes (CQA's) has been monitored in real time in a pilot-plant facility, using a NIR sensor. The sensitivity of the powder bulk density on critical process parameters (CPP's) and CQA's has been analyzed and thereby feed-forward controller has been designed. The measured signal can be used for feed-forward control so that the corrective actions on the density variations can be taken before they can influence the product quality. The coupled feed-forward/feed-back control system demonstrates improved control performance and improvements in the final product quality in the presence of process and raw material variations. Copyright © 2015 Elsevier B.V. All rights reserved.

Efficiency enhancement using voltage biasing for ferroelectric polarization in dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Kim, Sangmo; Song, Myoung Geun; Bark, Chung Wung

2018-01-01

Dye-sensitized solar cells (DSSCs) are one of the most promising third generation solar cells that have been extensively researched over the past decade as alternative to silicon-based solar cells, due to their low production cost and high energy-conversion efficiency. In general, a DSSC consists of a transparent electrode, a counter electrode, and an electrolyte such as dye. To achieve high power-conversion efficiency in cells, many research groups have focused their efforts on developing efficient dyes for liquid electrolytes. In this work, we report on the photovoltaic properties of DSSCs fabricated using a mixture of TiO2 with nanosized Fe-doped bismuth lanthanum titanate (nFe-BLT) powder). Firstly, nFe-BLT powders were prepared using a high-energy ball milling process and then, TiO2 and nFe-BLT powders were stoichiometrically blended. Direct current (DC) bias of 20 MV/m was applied to lab-made DSSCs. With the optimal concentration of nFe-BLT doped in the electrode, their light-to-electricity conversion efficiency could be improved by ∼64% compared with DSSCs where no DC bias was applied.

Quantification of synthetic cannabinoids in herbal smoking blends using NMR.

PubMed

Dunne, Simon J; Rosengren-Holmberg, Jenny P

2017-05-01

Herbal smoking blends containing synthetic cannabinoids have become popular alternatives to marijuana. These products were previously sold in pre-packaged foil bags, but nowadays seizures usually contain synthetic cannabinoid powders together with unprepared plant materials. A question often raised by the Swedish police is how much smoking blend can be prepared from certain amounts of banned substance, in order to establish the severity of the crime. To address this question, information about the synthetic cannabinoid content in both the powder and the prepared herbal blends is necessary. In this work, an extraction procedure compatible with direct NMR quantification of synthetic cannabinoids in herbal smoking blends was developed. Extraction media, time and efficiency were tested for different carrier materials containing representative synthetic cannabinoids. The developed protocol utilizes a 30 min extraction step in d 4 -methanol in presence of internal standard allowing direct quantitation of the extract using NMR. The accuracy of the developed method was tested using in-house prepared herbal smoking blends. The results showed deviations less than 0.2% from the actual content, proving that the method is sufficiently accurate for these quantifications. Using this method, ten synthetic cannabinoids present in sixty-three different herbal blends seized by the Swedish police between October 2012 and April 2015 were quantified. Obtained results showed a variation in cannabinoid contents from 1.5% (w/w) for mixtures containing MDMB-CHMICA to over 5% (w/w) for mixtures containing 5F-AKB-48. This is important information for forensic experts when making theoretical calculations of production quantities in legal cases regarding "home-made" herbal smoking blends. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

REDUCING POWER PRODUCTION COSTS BY UTILIZING PETROLEUM COKE

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

NONE

1998-09-01

A Powder River Basin subbituminous coal from the North Antelope mine and a petroleum shot coke were received from Northern States Power Company (NSP) for testing the effects of parent fuel properties on coal-coke blend grindability and evaluating the utility of petroleum coke blending as a strategy for improving electrostatic precipitator (ESP) particulate collection efficiency. Petroleum cokes are generally harder than coals, as indicated by Hardgrove grindability tests. Therefore, the weaker coal component may concentrate in the finer size fractions during the pulverizing of coal-coke blends. The possibility of a coal-coke size fractionation effect is being investigated because it maymore » adversely affect combustion performance. Although the blending of petroleum coke with coal may adversely affect combustion performance, it may enhance ESP particulate collection efficiency. Petroleum cokes contain much higher concentrations of V relative to coals. Consequently, coke blending can significantly increase the V content of fly ash resulting from coal-coke combustion. Pentavalent vanadium oxide (V{sub 2}O{sub 5}) is a known catalyst for transforming gaseous sulfur dioxide (SO{sub 2}[g]) to gaseous sulfur trioxide (SO{sub 3}[g]). The presence of SO{sub 3}(g) strongly affects fly ash resistivity and, thus, ESP performance.« less

At-line determination of pharmaceuticals small molecule's blending end point using chemometric modeling combined with Fourier transform near infrared spectroscopy

NASA Astrophysics Data System (ADS)

Tewari, Jagdish; Strong, Richard; Boulas, Pierre

2017-02-01

This article summarizes the development and validation of a Fourier transform near infrared spectroscopy (FT-NIR) method for the rapid at-line prediction of active pharmaceutical ingredient (API) in a powder blend to optimize small molecule formulations. The method was used to determine the blend uniformity end-point for a pharmaceutical solid dosage formulation containing a range of API concentrations. A set of calibration spectra from samples with concentrations ranging from 1% to 15% of API (w/w) were collected at-line from 4000 to 12,500 cm- 1. The ability of the FT-NIR method to predict API concentration in the blend samples was validated against a reference high performance liquid chromatography (HPLC) method. The prediction efficiency of four different types of multivariate data modeling methods such as partial least-squares 1 (PLS1), partial least-squares 2 (PLS2), principal component regression (PCR) and artificial neural network (ANN), were compared using relevant multivariate figures of merit. The prediction ability of the regression models were cross validated against results generated with the reference HPLC method. PLS1 and ANN showed excellent and superior prediction abilities when compared to PLS2 and PCR. Based upon these results and because of its decreased complexity compared to ANN, PLS1 was selected as the best chemometric method to predict blend uniformity at-line. The FT-NIR measurement and the associated chemometric analysis were implemented in the production environment for rapid at-line determination of the end-point of the small molecule blending operation. FIGURE 1: Correlation coefficient vs Rank plot FIGURE 2: FT-NIR spectra of different steps of Blend and final blend FIGURE 3: Predictions ability of PCR FIGURE 4: Blend uniformity predication ability of PLS2 FIGURE 5: Prediction efficiency of blend uniformity using ANN FIGURE 6: Comparison of prediction efficiency of chemometric models TABLE 1: Order of Addition for Blending Steps

[Research on whole blending end-point evaluation method of Angong Niuhuang Wan based on QbD concept].

PubMed

Liu, Xiao-Na; Zheng, Qiu-Sheng; Che, Xiao-Qing; Wu, Zhi-Sheng; Qiao, Yan-Jiang

2017-03-01

The blending end-point determination of Angong Niuhuang Wan (AGNH) is a key technology problem. The control strategy based on quality by design (QbD) concept proposes a whole blending end-point determination method, and provides a methodology for blending the Chinese materia medica containing mineral substances. Based on QbD concept, the laser induced breakdown spectroscopy (LIBS) was used to assess the cinnabar, realgar and pearl powder blending of AGNH in a pilot-scale experiment, especially the whole blending end-point in this study. The blending variability of three mineral medicines including cinnabar, realgar and pearl powder, was measured by moving window relative standard deviation (MWRSD) based on LIBS. The time profiles of realgar and pearl powder did not produce consistent results completely, but all of them reached even blending at the last blending stage, so that the whole proposal blending end point was determined. LIBS is a promising Process Analytical Technology (PAT) for process control. Unlike other elemental determination technologies such ICP-OES, LIBS does not need an elaborate digestion procedure, which is a promising and rapid technique to understand the blending process of Chinese materia medica (CMM) containing cinnabar, realgar and other mineral traditional Chinese medicine. This study proposed a novel method for the research of large varieties of traditional Chinese medicines.. Copyright© by the Chinese Pharmaceutical Association.

Downstream processing of a ternary amorphous solid dispersion: The impacts of spray drying and hot melt extrusion on powder flow, compression and dissolution.

PubMed

Davis, Mark T; Potter, Catherine B; Walker, Gavin M

2018-06-10

Downstream processing aspects of a stable form of amorphous itraconazole exhibiting enhanced dissolution properties were studied. Preparation of this ternary amorphous solid dispersion by either spray drying or hot melt extrusion led to significantly different powder processing properties. Particle size and morphology was analysed using scanning electron microscopy. Flow, compression, blending and dissolution were studied using rheometry, compaction simulation and a dissolution kit. The spray dried material exhibited poorer flow and reduced sensitivity to aeration relative to the milled extrudate. Good agreement was observed between differing forms of flow measurement, such as Flow Function, Relative flow function, Flow rate index, Aeration rate, the Hausner ratio and the Carr index. The stability index indicated that both powders were stable with respect to agglomeration, de-agglomeration and attrition. Tablet ability and compressibility studies showed that spray dried material could be compressed into stronger compacts than extruded material. Blending of the powders with low moisture, freely-flowing excipients was shown to influence both flow and compression. Porosity studies revealed that blending could influence the mechanism of densification in extrudate and blended extrudate formulations. Following blending, the powders were compressed into four 500 mg tablets, each containing a 100 mg dose of amorphous itraconazole. Dissolution studies revealed that the spray dried material released drug faster and more completely and that blending excipients could further influence the dissolution rate. Copyright © 2018 Elsevier B.V. All rights reserved.

Particle Size Effects on Flow Properties of PS304 Plasma Spray Feedstock Powder Blend

NASA Technical Reports Server (NTRS)

Stanford, Malcolm K.; DellaCorte, Christopher; Eylon, Daniel

2002-01-01

The effects of BaF2-CaF2 particle size and size distribution on PS304 feedstock powder flowability have been investigated. Angular BaF2-CaF2 eutectic powders were produced by comminution and classified by screening to obtain 38 to 45 microns 45 to 106 microns, 63 to 106 microns, 45 to 53 microns, 63 to 75 microns, and 90 to 106 microns particle size distributions. The fluorides were added incrementally from 0 to 10 wt% to the other powder constituents of the PS304 feedstock: nichrome, chromia, and silver powders. The flow rate of the powder blends decreased linearly with increasing concentration of the fluorides. Flow was degraded with decreasing BaF2-CaF2 particle size and with increasing BaF2-CaF2 particle size distribution. A semiempirical relationship is offered to describe the PS304 powder blend flow behavior. The Hausner Ratio confirmed the funnel flow test results, but was slightly less sensitive to differences in BaF2-CaF2 particle size and size distribution. These findings may have applicability to other powders that do not flow easily, such as ceramic powders.

Improved blend and tablet properties of fine pharmaceutical powders via dry particle coating.

PubMed

Huang, Zhonghui; Scicolone, James V; Han, Xi; Davé, Rajesh N

2015-01-30

The improvements in the flow and packing of fine pharmaceutical powder blends due to dry coating of micronized acetaminophen (mAPAP, ∼11μm), a model poorly flowing drug, are quantified. Poor flow and packing density of fine excipients (∼20μm) allowed testing the hypothesis that dry coating of cohesive API may counteract poor flow and packing of fine pharmaceutical powder blends. Further, fine excipients could improve compaction and reduce segregation tendency. It was found that flow function coefficient (FFC) and bulk density enhancements for 10%, 30%, and 60% (w/w), API loading blends with dry coated API are significantly higher than those without coated silica. At the highest API loading, for which coarser excipients were also used as reference, the flow and packing of dry coated mAPAP blends were significantly increased regardless of the excipient particle size, exceeding those of a well compacting excipient, Avicel 102. In addition, tensile strength of tablets with fine excipients was significantly higher, indicating improved compactibility. These results show for the first time that dry coating of fine, cohesive API powder leads to significantly improved flow and packing of high API loading blends consisting of fine excipients, while achieving improved tablet compactibility, suggesting suitability for direct compaction. Copyright © 2014 Elsevier B.V. All rights reserved.

Synthesis and Explosive Consolidation of Titanium, Aluminium, Boron and Carbon Containing Powders

NASA Astrophysics Data System (ADS)

Chikhradze, Mikheil; Oniashvili, George; Chikhradze, Nikoloz; D. S Marquis, Fernand

2016-10-01

The development of modern technologies in the field of materials science has increased the interest towards the bulk materials with improved physical, chemical and mechanical properties. Composites, fabricated in Ti-Al-B-C systems are characterized by unique physical and mechanical properties. They are attractive for aerospace, power engineering, machine and chemical applications. The technologies to fabricate ultrafine grained powder and bulk materials in Ti-Al-B-C system are described in the paper. It includes results of theoretical and experimental investigation for selection of powders composition and determination of thermodynamic conditions for bland preparation, as well as optimal technological parameters for mechanical alloying and adiabatic compaction. The crystalline coarse Ti, Al, C powders and amorphous B were used as precursors and blends with different compositions of Ti-Al, Ti-Al-C, Ti-B-C and Ti-Al-B were prepared. Preliminary determination/selection of blend compositions was made on the basis of phase diagrams. The powders were mixed according to the selected ratios of components to produce the blend. Blends were processed in “Fritsch” Planetary premium line ball mill for mechanical alloying, syntheses of new phases, amorphization and ultrafine powder production. The blends processing time was variable: 1 to 20 hours. The optimal technological regimes of nano blend preparation were determined experimentally. Ball milled nano blends were placed in metallic tube and loaded by shock waves for realization of consolidation in adiabatic regime. The structure and properties of the obtained ultrafine grained materials depending on the processing parameters are investigated and discussed. For consolidation of the mixture, explosive compaction technology is applied at room temperatures. The prepared mixtures were located in low carbon steel tube and blast energies were used for explosive consolidation compositions. The relationship of ball milling technological parameters and explosive consolidation conditions on the structure/properties of the obtained samples are described in the paper.

Efficient incorporation of silver to improve superconducting fibers

DOEpatents

Gleixner, Richard A.; LaCount, Dale F.; Finnemore, Douglas K.

1994-04-26

An improved method for the efficient incorporation of a metal such as silver in a superconducting material includes blending the metal with a high temperature superconductor or precursor powder and consolidating the same into pellets. The pellets are charged directly into a heating assembly where it is melted and heated sufficiently to a uniform temperature prior to fiberization. Droplets of the melted blend fall through a collar into a nozzle where they are subjected to a high velocity gas to break the melted material into ligaments which solidify into improved flexible fibers having the metal homogeneously dis This invention was made with Government support under a contract with the Department of Energy (DOE) and Ames Laboratory, Contract No. SC-91-225, our reference No. CRD-1272. The Government has certain rights in this invention.

First study of the evolution of the SeDeM expert system parameters based on percolation theory: Monitoring of their critical behavior.

PubMed

Galdón, Eduardo; Casas, Marta; Gayango, Manuel; Caraballo, Isidoro

2016-12-01

The deep understanding of products and processes has become a requirement for pharmaceutical industries to follow the Quality by Design principles promoted by the regulatory authorities. With this aim, SeDeM expert system was developed as a useful preformulation tool to predict the likelihood to process drugs and excipients through direct compression. SeDeM system is a step forward in the rational development of a formulation, allowing the normalisation of the rheological parameters and the identification of the weaknesses and strengths of a powder or a powder blend. However, this method is based on the assumption of a linear behavior of disordered systems. As percolation theory has demonstrated, powder blends behave as non-linear systems that can suffer abrupt changes in their properties near to geometrical phase transitions of the components. The aim of this paper was to analyze for the first time the evolution of the SeDeM parameters in drug/excipient powder blends from the point of view of the percolation theory and to compare the changes predicted by SeDeM with the predictions of Percolation theory. For this purpose, powder blends of lactose and theophylline with varying concentrations of the model drug have been prepared and the SeDeM analysis has been applied to each blend in order to monitor the evolution of their properties. On the other hand, percolation thresholds have been estimated for these powder blends where critical points have been found for important rheological parameters as the powder flow. Finally, the predictions of percolation theory and SeDeM have been compared concluding that percolation theory can complement the SeDeM method for a more accurate estimation of the Design Space. Copyright © 2016 Elsevier B.V. All rights reserved.

Evaluation of degree of blending colored diluents using color difference signal method.

PubMed

Miyazaki, Yasunori; Uchino, Tomonobu; Kagawa, Yoshiyuki

2014-01-01

We developed a color difference signal method to evaluate the degree of blending powdered medicines in pharmacies. In the method, the degree of blending is expressed as the relative standard deviation of the color difference signal value (Cb or Cr) of the YCbCr color space after digital photos of the blended medicines are analyzed by image processing. While the method is effective to determine the degree of blending colored medicines, it remains unknown whether it can be applied to uncolored or white-colored medicines. To investigate this, we examined colored diluents to identify an indicator of the degree mixtures are blended. In this study, we applied this method to Pontal® and Prednisolone® powders, which were used as uncolored and white-colored medicines, respectively. Each of these medicines was blended with the colored lactose using a pestle and mortar, and then the uniformity of blending was evaluated. The degree of blending was well-monitored in both mixtures with various blending ratios (1 : 9-9 : 1), showing a sufficient uniformity at 60 rotations of the pestle. Moreover, the Cr values of the mixtures with various blending ratios were correlated with the concentration of active pharmaceutical ingredients in these medicines, which was determined using HPLC. This indicated the usefulness of the color difference signal method for the quantitative determination of medicines. Thus, we demonstrated the applicability and effectiveness of this method to check dispensing powders.

[Near infrared analysis of blending homogeneity of Chinese medicine formula particles based on moving window F test method].

PubMed

Yang, Chan; Xu, Bing; Zhang, Zhi-Qiang; Wang, Xin; Shi, Xin-Yuan; Fu, Jing; Qiao, Yan-Jiang

2016-10-01

Blending uniformity is essential to ensure the homogeneity of Chinese medicine formula particles within each batch. This study was based on the blending process of ebony spray dried powder and dextrin(the proportion of dextrin was 10%),in which the analysis of near infrared (NIR) diffuse reflectance spectra was collected from six different sampling points in combination with moving window F test method in order to assess the blending uniformity of the blending process.The method was validated by the changes of citric acid content determined by the HPLC. The results of moving window F test method showed that the ebony spray dried powder and dextrin was homogeneous during 200-300 r and was segregated during 300-400 r. An advantage of this method is that the threshold value is defined statistically, not empirically and thus does not suffer from threshold ambiguities in common with the moving block standard deviatiun (MBSD). And this method could be employed to monitor other blending process of Chinese medicine powders on line. Copyright© by the Chinese Pharmaceutical Association.

Identification of low amount of irradiated spices (red pepper, garlic, ginger powder) with luminescence analysis

NASA Astrophysics Data System (ADS)

Kim, Byeong-Keun; Akram, Kashif; Kim, Cheong-Tae; Kang, Na-Roo; Lee, Jin-Won; Ryang, Jun-Hwan; Kwon, Joong-Ho

2012-08-01

For the identification of irradiated food, current analysis methods have limitations regarding presence and stability of radiation-induced markers. In this study, different spice blends with small quantity of different irradiated (0, 1 and 10 kGy) spice powders, such as red pepper, garlic or ginger, were investigated using PSL and TL techniques. In PSL-based screening analysis, the spice blends containing 10% of irradiated materials (1 or 10 kGy) were determined as intermediate or positive. In TL results, the blends containing 1% of 1 or 10 kGy-irradiated spices showed the typical TL glow curves that could be interpreted as positive. The blends with irradiated garlic powder provided more good results where identification was possible at 0.5% mixing of irradiated sample. However, the TL ratios of all spice blends were <0.1 and only TL glow curve shape and intensity may be used to discriminate the samples having irradiated component.

Reducing power production costs by utilizing petroleum coke. Annual report

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

Galbreath, K.C.

1998-07-01

A Powder River Basin subbituminous coal from the North Antelope mine and a petroleum shot coke were received from Northern States Power Company (NSP) for testing the effects of parent fuel properties on coal-coke blend grindability and evaluating the utility of petroleum coke blending as a strategy for improving electrostatic precipitator (ESP) particulate collection efficiency. Petroleum cokes are generally harder than coals, as indicated by Hardgrove grindability tests. Therefore, the weaker coal component may concentrate in the finer size fractions during the pulverizing of coal-coke blends. The possibility of a coal-coke size fractionation effect is being investigated because it maymore » adversely affect combustion performance, it may enhance ESP particulate collection efficiency. Petroleum cokes contain much higher concentrations of V relative to coals. Consequently, coke blending can significantly increase the V content of fly ash resulting from coal-coke combustion. Pentavalent vanadium oxide (V{sub 2}O{sub 5}) is a known catalyst for transforming gaseous sulfur dioxide (SO{sub 2}[g]) to gaseous sulfur trioxide (SO{sub 3}[g]). The presence of SO{sub 3}(g) strongly affects fly ash resistivity and, thus, ESP performance.« less

A Science and Risk-Based Pragmatic Methodology for Blend and Content Uniformity Assessment.

PubMed

Sayeed-Desta, Naheed; Pazhayattil, Ajay Babu; Collins, Jordan; Doshi, Chetan

2018-04-01

This paper describes a pragmatic approach that can be applied in assessing powder blend and unit dosage uniformity of solid dose products at Process Design, Process Performance Qualification, and Continued/Ongoing Process Verification stages of the Process Validation lifecycle. The statistically based sampling, testing, and assessment plan was developed due to the withdrawal of the FDA draft guidance for industry "Powder Blends and Finished Dosage Units-Stratified In-Process Dosage Unit Sampling and Assessment." This paper compares the proposed Grouped Area Variance Estimate (GAVE) method with an alternate approach outlining the practicality and statistical rationalization using traditional sampling and analytical methods. The approach is designed to fit solid dose processes assuring high statistical confidence in both powder blend uniformity and dosage unit uniformity during all three stages of the lifecycle complying with ASTM standards as recommended by the US FDA.

Investigation into process-induced de-aggregation of cohesive micronised API particles.

PubMed

Hoffmann, Magnus; Wray, Patrick S; Gamble, John F; Tobyn, Mike

2015-09-30

The aim of this study was to assess the impact of unit processes on the de-aggregation of a cohesive micronised API within a pharmaceutical formulation using near-infrared chemical imaging. The impact on the primary API particles was also investigated using an image-based particle characterization system with integrated Raman analysis. The blended material was shown to contain large, API rich domains which were distributed in-homogeneously across the sample, suggesting that the blending process was not aggressive enough to disperse aggregates of micronised drug particles. Cone milling, routinely used to improve the homogeneity of such cohesive formulations, was observed to substantially reduce the number and size of API rich domains; however, several smaller API domains survived the milling process. Conveyance of the cone milled formulation through the Alexanderwerk WP120 powder feed system completely dispersed all remaining aggregates. Importantly, powder feed transmission of the un-milled formulation was observed to produce an equally homogeneous API distribution. The size of the micronised primary drug particles remained unchanged during powder feed transmission. These findings provide further evidence that this powder feed system does induce shear, and is in fact better able to disperse aggregates of a cohesive micronised API within a blend than the blend-mill-blend step. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

Surface modification of lactose inhalation blends by moisture.

PubMed

Watling, C P; Elliott, J A; Scruton, C; Cameron, R E

2010-05-31

We present an investigation of the effects of relative humidity (RH) on lactose powders during storage, with the aims of determining the humidity conditions under which lactose inhalation blends are stable, and characterising the surface changes that occur as a result of water condensation. Lactose inhalation powders manufactured by milling and sieving were stored in environments of RH from 32% to 100% (at room temperature) and changes in surface properties were observed using BET nitrogen adsorption, environmental scanning electron microscopy and laser diffraction particle size analysis. We found that the specific surface area of all lactose powders decreased during storage, with the rate of decrease and final drop being larger at higher RH (ranging from a 62% decrease at 100% RH to a 34% decrease at 32% RH, at room temperature). The specific surface area decrease corresponded to a reduction in the volume of fine particles (<5 microm) in the blend. Two effects were found to contribute to the decrease in specific surface area: the smoothing of coarse particles, attributed to the surface fine particles undergoing deliquescence due to their enhanced solubility by the Kelvin effect (i.e. due to their greater curvature and consequently greater surface energy), and solid bridging between fine particles in agglomerates, such that loose fine particles disappeared from the powder blend, having bonded with coarser particles. These changes in particle properties resulting from moisture exposure are expected to influence the fine particle fraction of drug released from the powder blends, and the observation that lactose inhalation blends were unstable even at 32% RH could potentially be a concern for the pharmaceutical industry. Copyright (c) 2010 Elsevier B.V. All rights reserved.

An Investigation into the Physico-chemical Properties of Transformer Oil Blends with Antioxidants extracted from Turmeric Powder

NASA Astrophysics Data System (ADS)

Dukhi, Veresha; Bissessur, Ajay; Ngila, Catherine Jane; Ijumba, Nelson Mutatina

2013-07-01

The blending of transformer oil (used mainly as an insulating oil) with appropriate synthetic antioxidants, such as BHT (2,6-di-tert-butyl-4-methylphenol) and DBP (2,6-di-tert-butylphenol) have been previously reported. This article is focused on the use of antioxidant extracts from turmeric (Curcuma longa), a natural source. Turmeric is well known for its antimicrobial, antioxidant and anticarcinogenic properties owing to the active nature of its components. Extracts from powdered turmeric were subsequently blended into naphthenic-based uninhibited virgin transformer oil, hereinafter referred to as extract-oil blends (E-OB). Thin-layer chromatography (TLC) of the oil blends revealed that five components extracted from turmeric powder were successfully blended into the oil. Subsequent gas chromatography-mass spectrometry (GC-MS) analysis confirmed the presence of the compounds: curcumene, sesquiphellandrene, ar-turmerone, turmerone and curlone. Thermogravimetric analysis (TGA) of the extract-oil blends, containing various levels of extracts, revealed an average temperature shift of ˜8.21°C in the initial onset of degradation in comparison to virgin non-blended oil. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay showed that an increase in the mass aliquot of turmeric extracts in the transformer oil increased the free radical scavenging activity of the oil. Electrical properties of the oil investigated showed that the dissipation factor in the blended oil was found to be lower than that of virgin transformer oil. Evidently, a lower dissipation value renders the oil blend as a superior insulator over normal virgin non-blended oil. This investigation elucidated improved physico-chemical properties of transformer oil blended with turmeric antioxidant extracts.

Silicon nitride-aluminum oxide solid solution (SiAION) formation and densification by pressure sintering

NASA Technical Reports Server (NTRS)

Yeh, H. C.; Sanders, W. A.; Fiyalko, J. L.

1975-01-01

Stirred-ball-mill-blended Si3N4 and Al2O3 powders were pressure sintered in order to investigate the mechanism of solid solution formation and densification in the Si3N4-Al2O3 system. Powder blends with Si3N4:Al2O3 mole ratios of 4:1, 3:2, and 2:3 were pressure sintered at 27.6-MN/sq m pressure at temperatures to 17000 C (3090 F). The compaction behavior of the powder blends during pressure sintering was determined by observing the density of the powder compact as a function of temperature and time starting from room temperature. This information, combined with the results of X-ray diffraction and metallographic analyses regarding solutioning and phase transformation phenomena in the Si3N4-Al2O3 system, was used to describe the densification behavior.

Response to Thermal Exposure of Ball-Milled Aluminum-Borax Powder Blends

NASA Astrophysics Data System (ADS)

Birol, Yucel

2013-04-01

Aluminum-borax powder mixtures were ball milled and heated above 873 K (600 °C) to produce Al-B master alloys. Ball-milled powder blends reveal interpenetrating layers of deformed aluminum and borax grains that are increasingly refined with increasing milling time. Thermal exposure of the ball-milled powder blends facilitates a series of thermite reactions between these layers. Borax, dehydrated during heating, is reduced by Al, and B thus generated reacts with excess Al to produce AlB2 particles dispersed across the aluminum grains starting at 873 K (600 °C). AlB2 particles start to form along the interface of the aluminum and borax layers. Once nucleated, these particles grow readily to become hexagonal-shaped crystals that traverse the aluminum grains with increasing temperatures as evidenced by the increase in the size as well as in the number of the AlB2 particles. Ball milling for 1 hour suffices to achieve a thermite reaction between borax and aluminum. Ball milling further does not impact the response of the powder blend to thermal exposure. The nucleation-reaction sites are multiplied, however, with increasing milling time and thus insure a higher number of smaller AlB2 particles. The size of the AlB2 platelets may be adjusted with the ball milling time.

Evaluation of Granulated Lactose as a Carrier for Dry Powder Inhaler Formulations 2: Effect of Drugs and Drug Loading.

PubMed

Du, Ping; Du, Ju; Smyth, Hugh D C

2017-01-01

Previously, granulated lactose carriers were shown to improve uniformity and aerosolization of a low-dose model drug. In the present study, the blending uniformity and aerosol dispersion performance were assessed for 2 model drugs salbutamol sulfate (SS) and rifampicin (RIF), blended at high loadings (10% or 30% drug) with granulated lactose carriers. The model drug powders differed in particle size distribution, morphology, density, and surface energies. Content uniformity of RIF blends was better than that of SS. Aerosolization studies showed that all blend formulations had acceptable emitted fractions (>70%). The SS blends showed low induction-port deposition (6%-10%) compared to RIF (5%-30%). This difference was greater at high flow rates. At 90 L/min, the low induction port deposition of SS blends allowed high fine particle fraction (FPF) of 73%-81%, whereas the FPF of the RIF blends was around 43%-45% with higher induction port deposition. However, SS blends exhibited strong flow rate-dependent performance. Increasing the flow rate from 30 L/min to 90 L/min increased SS FPF from approximately 20% to 80%. Conversely, RIF blends were flow rate and drug loading independent. It was concluded that the aerosolization of high drug-loaded dry powder inhaler formulations using granulated lactose, particularly flow rate dependency, varies with active pharmaceutical ingredient properties. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

A robust quantitative near infrared modeling approach for blend monitoring.

PubMed

Mohan, Shikhar; Momose, Wataru; Katz, Jeffrey M; Hossain, Md Nayeem; Velez, Natasha; Drennen, James K; Anderson, Carl A

2018-01-30

This study demonstrates a material sparing Near-Infrared modeling approach for powder blend monitoring. In this new approach, gram scale powder mixtures are subjected to compression loads to simulate the effect of scale using an Instron universal testing system. Models prepared by the new method development approach (small-scale method) and by a traditional method development (blender-scale method) were compared by simultaneously monitoring a 1kg batch size blend run. Both models demonstrated similar model performance. The small-scale method strategy significantly reduces the total resources expended to develop Near-Infrared calibration models for on-line blend monitoring. Further, this development approach does not require the actual equipment (i.e., blender) to which the method will be applied, only a similar optical interface. Thus, a robust on-line blend monitoring method can be fully developed before any large-scale blending experiment is viable, allowing the blend method to be used during scale-up and blend development trials. Copyright © 2017. Published by Elsevier B.V.

Physicochemical properties of film-coated melt-extruded pellets.

PubMed

Young, Chistopher R; Crowley, Michael; Dietzsch, Caroline; McGinity, James W

2007-02-01

The purpose of this study was to investigate the physicochemical properties of poly(ethylene oxide) (PEO) and guaifenesin containing beads prepared by a melt-extrusion process and film-coated with a methacrylic acid copolymer. Solubility parameter calculations, thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), modulated differential scanning calorimetry (MDSC), X-ray powder diffraction (XRPD) and high performance liquid chromatography (HPLC) were used to determine drug/polymer miscibility and/or the thermal processibility of the systems. Powder blends of guaifenesin, PEO and functional excipients were processed using a melt-extrusion and spheronization technique and then film-coated in a fluidized bed apparatus. Solubility parameter calculations were used to predict miscibility between PEO and guaifenesin, and miscibility was confirmed by SEM and observation of a single melting point for extruded drug/polymer blends during MDSC investigations. The drug was stable following melt-extrusion as determined by TGA and HPLC; however, drug release rate from pellets decreased upon storage in sealed HDPE containers with silica desiccants at 40 degrees C/75% RH. The weight loss on drying, porosity and tortuosity determinations were not influenced by storage. Recrystallization of guaifenesin and PEO was confirmed by SEM and XRPD. Additionally, the pellets exhibited a change in adhesion behaviour during dissolution testing. The addition of ethylcellulose to the extruded powder blend decreased and stabilized the drug release rate from the thermally processed pellets. The current study also demonstrated film-coating to be an efficient process for providing melt-extruded beads with pH-dependent drug release properties that were stable upon storage at accelerated conditions.

Automated system for the on-line monitoring of powder blending processes using near-infrared spectroscopy. Part I. System development and control.

PubMed

Hailey, P A; Doherty, P; Tapsell, P; Oliver, T; Aldridge, P K

1996-03-01

An automated system for the on-line monitoring of powder blending processes is described. The system employs near-infrared (NIR) spectroscopy using fibre-optics and a graphical user interface (GUI) developed in the LabVIEW environment. The complete supervisory control and data analysis (SCADA) software controls blender and spectrophotometer operation and performs statistical spectral data analysis in real time. A data analysis routine using standard deviation is described to demonstrate an approach to the real-time determination of blend homogeneity.

Engineered particles demonstrate improved flow properties at elevated drug loadings for direct compression manufacturing.

PubMed

Trementozzi, Andrea N; Leung, Cheuk-Yui; Osei-Yeboah, Frederick; Irdam, Erwin; Lin, Yiqing; MacPhee, J Michael; Boulas, Pierre; Karki, Shyam B; Zawaneh, Peter N

2017-05-15

Optimizing powder flow and compaction properties are critical for ensuring a robust tablet manufacturing process. The impact of flow and compaction properties of the active pharmaceutical ingredient (API) becomes progressively significant for higher drug load formulations, and for scaling up manufacturing processes. This study demonstrated that flow properties of a powder blend can be improved through API particle engineering, without critically impacting blend tabletability at elevated drug loadings. In studying a jet milled API (D 50 =24μm) and particle engineered wet milled API (D 50 =70μm and 90μm), flow functions of all API lots were similarly poor despite the vast difference in average particle size (ff c <4). This finding strays from the common notion that powder flow properties are directly correlated to particle size distribution. Upon adding excipients, however, clear trends in flow functions based on API particle size were observed. Wet milled API blends had a much improved flow function (ff c >10) compared with the jet milled API blends. Investigation of the compaction properties of both wet and jet milled powder blends also revealed that both jet and wet milled material produced robust tablets at the drug loadings used. The ability to practically demonstrate this uncommon observation that similarly poor flowing APIs can lead to a marked difference upon blending is important for pharmaceutical development. It is especially important in early phase development during API selection, and is advantageous particularly when material-sparing techniques are utilized. Copyright © 2017 Elsevier B.V. All rights reserved.

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

Plasma spray processing of TiC-based coatings for sliding wear resistance

NASA Astrophysics Data System (ADS)

Mohanty, Mahesh

Titanium carbide-reinforced metallic coatings, produced by plasma spraying, can be used for sliding wear resistant applications. The sliding wear properties of such coatings are governed to a large extent by the strength, structure and stability of the bond interface between the carbide and the metallic phases. In the present investigation, the microstructure and sliding wear properties of plasma sprayed metal-bonded TiC coatings containing up to 90 v/o carbide have been studied. It was shown that alloying of the metallic phase improved carbide retention in TiC cermets due to better interface bonding, and increased wear resistance and lowered sliding coefficient of friction. TiC-based coatings were produced from both physically blended and synthesized feed powders. It was observed that the precursor TiC-based powder morphology and structure greatly affected the plasma sprayed coating microstructures and the resultant physical and mechanical characteristics. Physical blending of powders induced segregation during spraying, leading to somewhat lower deposit efficiencies and coating uniformity, while synthesized and alloyed titanium carbide/metal composite powders reduced problems of segregation and reactions associated with plasma spraying of physically blended powders where the TiC was in direct contact with the plasma jet. To understand oxidation effects of the environment, Ti and TiC-based coatings were produced under low pressure (VPS), air plasma (APS) and shrouded plasma sprayed conditions. APS Ti and TiC-based powders with reactive matrices suffered severe oxidation decomposition during flight, leading to poor deposition efficiencies and oxidized microstructures. High particle temperatures and cold air plasma spraying. Coating oxidation due to reactions of the particles with the surrounding air during spraying reduced coating hardness and wear resistance. TiC-with Ti or Ti-alloy matrix coatings with the highest hardness, density and wear resistance was achieved by spraying under vacuum plasma spray conditions. VPS coating microstructures of synthesized 40, 60 and 80 v/o TiC in Ti10Ni10Cr5Al and 80 v/o TiC in Fe30Cr alloy matrices exhibited fine and uniform distributions of spheroidal carbides. High volume fraction carbides were also obtained with no segregation effects. It was also shown that coatings produced from mechanically blended powders of 50, 70 and 90 vol. % TiC and commercially pure (C.P.) Ti, using low pressure plasma spray process (VPS), had densities >98% and were well bonded to steel, aluminum alloy or titanium alloy substrates. Reductions in jet oxygen contents by the use of an inert gas shroud enabled Ti and TiC-based coatings to be produced which were cleaner and denser than air plasma sprayed and comparable to vacuum plasma sprayed coatings. Direct oxygen concentration measurements in shrouded plasma jets made using an enthalpy probe and a gas analyzer also showed significant reductions in the entrainment of atmospheric oxygen. VPS and shrouded plasma spraying minimized carbide-matrix interface oxidation and improved coating wear resistance. The sliding wear resistance of synthesized coatings was very high and comparable with standard HVOF sprayed WC/Co and Crsb3Csb2/NiCr coatings. Shrouded plasma spray deposits of Crsb3Csb2/NiCr also performed much better than similar air plasma sprayed coatings, as result of reduced oxidation.

Method for hot pressing beryllium oxide articles

DOEpatents

Ballard, Ambrose H.; Godfrey, Jr., Thomas G.; Mowery, Erb H.

1988-01-01

The hot pressing of beryllium oxide powder into high density compacts with little or no density gradients is achieved by employing a homogeneous blend of beryllium oxide powder with a lithium oxide sintering agent. The lithium oxide sintering agent is uniformly dispersed throughout the beryllium oxide powder by mixing lithium hydroxide in an aqueous solution with beryllium oxide powder. The lithium hydroxide is converted in situ to lithium carbonate by contacting or flooding the beryllium oxide-lithium hydroxide blend with a stream of carbon dioxide. The lithium carbonate is converted to lithium oxide while remaining fixed to the beryllium oxide particles during the hot pressing step to assure uniform density throughout the compact.

Blend uniformity evaluation during continuous mixing in a twin screw granulator by in-line NIR using a moving F-test.

PubMed

Fonteyne, Margot; Vercruysse, Jurgen; De Leersnyder, Fien; Besseling, Rut; Gerich, Ad; Oostra, Wim; Remon, Jean Paul; Vervaet, Chris; De Beer, Thomas

2016-09-07

This study focuses on the twin screw granulator of a continuous from-powder-to-tablet production line. Whereas powder dosing into the granulation unit is possible from a container of preblended material, a truly continuous process uses several feeders (each one dosing an individual ingredient) and relies on a continuous blending step prior to granulation. The aim of the current study was to investigate the in-line blending capacity of this twin screw granulator, equipped with conveying elements only. The feasibility of in-line NIR (SentroPAT, Sentronic GmbH, Dresden, Germany) spectroscopy for evaluating the blend uniformity of powders after the granulator was tested. Anhydrous theophylline was used as a tracer molecule and was blended with lactose monohydrate. Theophylline and lactose were both fed from a different feeder into the twin screw granulator barrel. Both homogeneous mixtures and mixing experiments with induced errors were investigated. The in-line spectroscopic analyses showed that the twin screw granulator is a useful tool for in-line blending in different conditions. The blend homogeneity was evaluated by means of a novel statistical method being the moving F-test method in which the variance between two blocks of collected NIR spectra is evaluated. The α- and β-error of the moving F-test are controlled by using the appropriate block size of spectra. The moving F-test method showed to be an appropriate calibration and maintenance free method for blend homogeneity evaluation during continuous mixing. Copyright © 2016 Elsevier B.V. All rights reserved.

Antioxidant activity and polyphenolic compound stability of lentil-orange peel powder blend in an extrusion process.

PubMed

Rathod, Rahul P; Annapure, Uday S

2017-03-01

Lentil contains substantial amount of protein, carbohydrate, fibre and other nutrients and orange peels powder rich in carbohydrate and fiber content The present study was aimed to investigate the effects of extrusion processing parameter on the level of total phenolic content (TPC), total flavonoid content (TFC), total tannin content and antioxidant activity of lentil-orange peel powder blend, also to investigate the possibility of blend as a candidate for production of protein rich extruded product by using response surface methodology. It was observed that, the physicochemical properties and sensory characteristics of lentil-orange peel based extrudate were highly dependent on process variables. The blend of lentil and orange peel powder has a huge potential for extrusion to produce ready-to-eat extruded with good acceptance. The overall best quality product was optimized and obtained at 16% moisture, 150 °C die temperature and 200 rpm screw speed. Extrusion process increased nutritional value of extruded product with TPC and TFC of 70.4 and 67.62% respectively and antioxidant activity of 60.6%. It showed higher stability at 150 °C with intermediate feed moisture content and despite the use of high temperatures in the extrusion-cooking is possible to minimize the loss of bioactive compounds to achieve products. Thus, results indicated that blend of lentil and orange peel may be used as raw material for the production of extruded snacks with great nutritional value.

Entrainment of lactose inhalation powders: a study using laser diffraction.

PubMed

Watling, C P; Elliott, J A; Cameron, R E

2010-07-11

We have investigated the mechanism of entrainment of lactose inhalation blends released from a dry powder inhaler using a diffraction particle size analyser (Malvern Spraytec). Whether a powder blend entrains as a constant stream of powder (the "erosion" mechanism) or as a few coarse plugs (the "fracture" mechanism) was found by comparing transmission data with particle size information. This technique was then applied to a lactose grade with 0, 5 and 10wt% added fine particles. As the wt% fines increased, the entrainment mechanism was found to change from a mild fracture, consisting of multiple small plugs, to more severe fracture with fewer plugs. The most severe fracture mechanism consisted of either the powder reservoir emptying as a single plug, or of the reservoir emptying after a delay of the order of 0.1s due to the powder sticking to its surroundings. Further to this, three different inhalation grades were compared, and the severity of the fracture was found to be inversely proportional to the flowability of the powder (measured using an annular ring shear tester). By considering the volume of aerosolised fine particles in different blends it was determined that the greater the volume of fines added to a powder, the smaller the fraction of fines that were aerosolised. This was attributed to different behaviour when fines disperse from carrier particles compared with when they disperse from agglomerates of fines. In summary, this paper demonstrates how laser diffraction can provide a more detailed analysis of an inhalation powder than just its size distribution. 2010. Published by Elsevier B.V. All rights reserved.

Thermal insulation for high temperature microwave sintering operations and method thereof

DOEpatents

Holcombe, Cressie E.; Dykes, Norman L.; Morrow, Marvin S.

1995-01-01

Superior microwave transparent thermal insulations for high temperature microwave sintering operations were prepared. One embodiment of the thermal insulation comprises granules of boron nitride coated with a very thin layer of glassy carbon made by preparing a glassy carbon precursor and blending it with boron nitride powder to form a mixture. The blended mixture is granulated to form a grit which is dried and heated to form the granules of boron nitride coated with a glassy carbon. Alternatively, grains of glassy carbon are coated with boron nitride by blending a mixture of a slurry comprising boron nitride, boric acid binder, and methyl alcohol with glassy carbon grains to form a blended mixture. The blended mixture is dried to form grains of glassy carbon coated with boron nitride. In addition, a physical mixture of boron nitride powder and glassy carbon grains has also been shown to be an excellent thermal insulation material for microwave processing and sintering.

Method of preparing thermal insulation for high temperature microwave sintering operations

DOEpatents

Holcombe, Cressie E.; Dykes, Norman L.; Morrow, Marvin S.

1996-01-01

Superior microwave transparent thermal insulations for high temperature microwave sintering operations were prepared. One embodiment of the thermal insulation comprises granules of boron nitride coated with a very thin layer of glassy carbon made by preparing a glassy carbon precursor and blending it with boron nitride powder to form a mixture. The blended mixture is granulated to form a grit which is dried and heated to form the granules of boron nitride coated with a glassy carbon. Alternatively, grains of glassy carbon are coated with boron nitride by blending a mixture of a slurry comprising boron nitride, boric acid binder, and methyl alcohol with glassy carbon grains to form a blended mixture. The blended mixture is dried to form grains of glassy carbon coated with boron nitride. In addition, a physical mixture of boron nitride powder and glassy carbon grains has also been shown to be an excellent thermal insulation material for microwave processing and sintering.

DSC and TG Analysis of a Blended Binder Based on Waste Ceramic Powder and Portland Cement

NASA Astrophysics Data System (ADS)

Pavlík, Zbyšek; Trník, Anton; Kulovaná, Tereza; Scheinherrová, Lenka; Rahhal, Viviana; Irassar, Edgardo; Černý, Robert

2016-03-01

Cement industry belongs to the business sectors characteristic by high energy consumption and high {CO}2 generation. Therefore, any replacement of cement in concrete by waste materials can lead to immediate environmental benefits. In this paper, a possible use of waste ceramic powder in blended binders is studied. At first, the chemical composition of Portland cement and ceramic powder is analyzed using the X-ray fluorescence method. Then, thermal and mechanical characterization of hydrated blended binders containing up to 24 % ceramic is carried out within the time period of 2 days to 28 days. The differential scanning calorimetry and thermogravimetry measurements are performed in the temperature range of 25°C to 1000°C in an argon atmosphere. The measurement of compressive strength is done according to the European standards for cement mortars. The thermal analysis results in the identification of temperature and quantification of enthalpy and mass changes related to the liberation of physically bound water, calcium-silicate-hydrates dehydration and portlandite, vaterite and calcite decomposition. The portlandite content is found to decrease with time for all blends which provides the evidence of the pozzolanic activity of ceramic powder even within the limited monitoring time of 28 days. Taking into account the favorable results obtained in the measurement of compressive strength, it can be concluded that the applied waste ceramic powder can be successfully used as a supplementary cementing material to Portland cement in an amount of up to 24 mass%.

Process for applying a superconductive powder to a wide variety of substrates

NASA Astrophysics Data System (ADS)

Hooker, Matthew W.; Wise, Stephanie A.; Tran, Sang Q.

1992-12-01

A fine superconducting powder such as YBa2Cu3O(7-x), wherein x is less than one, is blended into a liquid mixture comprising an epoxy resin and a thinner. This liquid mixture with the blended superconducting powder is coated onto a substrate. Next, the thinner is evaporated and the remaining coating cured, resulting in a coating of cured epoxy resin having superconducting powder suspended therein. This coating exhibits the Meissner effect, i.e., it expels a magnetic flux which protects the substrate from external magnetic interference. Since the coated substrate need only be heated for evaporation and curing at relatively low temperatures compared to firing, the superconducting coating can be applied to a wide variety of different materials.

Pyrotechnic filled molding powder

DOEpatents

Hartzel, Lawrence W.; Kettling, George E.

1978-01-01

The disclosure relates to thermosetting molding compounds and more particularly to a pyrotechnic filled thermosetting compound comprising a blend of unfilled diallyl phthalate molding powder and a pyrotechnic mixture.

Predicting the quality of powders for inhalation from surface energy and area.

PubMed

Cline, David; Dalby, Richard

2002-09-01

To correlate the surface energy of active and carrier components in an aerosol powder to in vitro performance of a passive dry powder inhaler. Inverse gas chromatography (IGC) was used to assess the surface energy of active (albuterol and ipratropium bromide) and carrier (lactose monohydrate, trehalose dihydrate and mannitol) components of a dry powder inhaler formulation. Blends (1%w/w) of drug and carrier were prepared and evaluated for dry powder inhaler performance by cascade impaction. The formulations were tested with either of two passive dry powder inhalers, Rotahaler (GlaxoSmithKline) or Handihaler (Boehringer Ingelheim). In vitro performance of the powder blends was strongly correlated to surface energy interaction between active and carrier components. Plotting fine particle fraction vs. surface energy interaction yielded an R2 value of 0.9283. Increasing surface energy interaction between drug and carrier resulted in greater fine particle fraction of drug. A convincing relationship, potentially useful for rapid formulation design and screening, was found between the surface energy and area parameters derived from IGC and dry powder inhaler performance.

A Self-Propagating Foaming Process of Porous Al-Ni Intermetallics Assisted by Combustion Reactions

PubMed Central

Kobashi, Makoto; Kanetake, Naoyuki

2009-01-01

The self-propagating foaming process of porous Al-Ni intermetallics was investigated. Aluminum and nickel powders were blended, and titanium and boron carbide powders were added as reactive exothermic agents. The blended powder was extruded to make a rod-shape precursor. Only one end of the rod precursor was heated to ignite the reaction. The reaction propagated spontaneously throughout the precursor. Pore formation took place at the same time as the reaction occurred. Adding the exothermic agent was effective to increase the porosity. Preheating the precursor before the ignition was also very effective to produce porous Al-Ni intermetallics with high porosity.

Process Of Bonding Copper And Tungsten

DOEpatents

Slattery, Kevin T.; Driemeyer, Daniel E.

1999-11-23

Process for bonding a copper substrate to a tungsten substrate by providing a thin metallic adhesion promoting film bonded to a tungsten substrate and a functionally graded material (FGM) interlayer bonding the thin metallic adhesion promoting film to the copper substrate. The FGM interlayer is formed by thermal plasma spraying mixtures of copper powder and tungsten powder in a varied blending ratio such that the blending ratio of the copper powder and the tungsten powder that is fed to a plasma torch is intermittently adjusted to provide progressively higher copper content/tungsten content, by volume, ratio values in the interlayer in a lineal direction extending from the tungsten substrate towards the copper substrate. The resulting copper to tungsten joint well accommodates the difference in the coefficient of thermal expansion of the materials.

Characterization of composite materials based on cement-ceramic powder blended binder

NASA Astrophysics Data System (ADS)

Kulovaná, Tereza; Pavlík, Zbyšek

2016-06-01

Characterization of newly developed composite mortars with incorporated ceramic powder coming from precise brick cutting as partial Portland cement replacement up to 40 mass% is presented in the paper. Fine ceramic powder belongs to the pozzolanic materials. Utilization of pozzolanic materials is accompanied by lower request on energy needed for Portland clinker production which generally results in lower production costs of blended binder and lower CO2 emission. In this paper, the ceramic powder is used in cement based mortar composition in amount of 8, 16, 24, 32, and 40 mass% of cement. Chemical composition of ceramic powder is analyzed by X-Ray Fluorescence and X-Ray Diffraction. The particle size distribution of ceramics is accessed on laser diffraction principle. For 28 days cured mortar samples, basic physical and mechanical properties are experimentally determined. The obtained results demonstrate that ceramic powder has potential to replace a part of Portland cement in composition of cement based composites and to reduce negative environmental impact of their production.

Characterization of composite materials based on cement-ceramic powder blended binder

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

Kulovaná, Tereza; Pavlík, Zbyšek

Characterization of newly developed composite mortars with incorporated ceramic powder coming from precise brick cutting as partial Portland cement replacement up to 40 mass% is presented in the paper. Fine ceramic powder belongs to the pozzolanic materials. Utilization of pozzolanic materials is accompanied by lower request on energy needed for Portland clinker production which generally results in lower production costs of blended binder and lower CO{sub 2} emission. In this paper, the ceramic powder is used in cement based mortar composition in amount of 8, 16, 24, 32, and 40 mass% of cement. Chemical composition of ceramic powder is analyzedmore » by X-Ray Fluorescence and X-Ray Diffraction. The particle size distribution of ceramics is accessed on laser diffraction principle. For 28 days cured mortar samples, basic physical and mechanical properties are experimentally determined. The obtained results demonstrate that ceramic powder has potential to replace a part of Portland cement in composition of cement based composites and to reduce negative environmental impact of their production.« less

Evolution of Immiscibly Blended Functionalized Polymers with Respect to Cure Parameters and Formulation

NASA Astrophysics Data System (ADS)

Heller, Nicholas Walter Medicus

Powder coatings are becoming ubiquitous in the coating marketplace due to the absence of solvents in their formulation, but they have yet to see implementation in low-reflectance outdoor applications. This demand could be met by utilizing polymer blends formulated with low loadings of matting agents and pigments. The goal of this research is a thorough characterization of prototype low-reflectance coatings through several analytical techniques. Prototypical thermoset blends consist of functionalized polyurethanes rendered immiscible by differences in polar and hydrogen bonding characteristics, resulting in a surface roughened by droplet domains. Analysis of both pigmented and control clear films was performed. This research project had three primary aims: (1) determine the composition of the resin components of the polymer blend; (2) to monitor the evolution of domains before and during curing of clear polymer blends; (3) to monitor the evolution of these domains when pigments are added to these blends. The clear films enabled unhindered analysis by Fourier transform infrared (FTIR) and Raman spectroscopy on the binder. However, these domains provided no spectroscopic signatures despite their observation by optical microscopy. This necessitated the development of a new procedure for cross-section preparation that leaves no contamination from polishing media, which enabled Raman mapping of the morphology via an introduced marker peak from styrene monomer. The clears were analyzed as a powder and as films that were quenched at various cure-times using FTIR, Raman, transmission electron microscopy (TEM), and thermomechanical methods to construct a model of coating evolution based on cure parameters and polymer dynamics. Domains were observed in the powder, and underwent varying rates of coarsening as the cure progressed. TEM, scanning electron microscopy and thermomechanical methods were also used on pigmented systems at different states of the cure, including in powder form. TEM analysis additionally revealed the encapsulation of pigment particles by the domains, which helped explain the interaction between phase separation and pigment materials. The knowledge gained from fundamental characterization could be used to enable future generations of durable powder coatings with dead matte finishes.

Mechanical properties of melt-processed polymer blend of amorphous corn flour composite filler and styrene-butadiene rubber

USDA-ARS?s Scientific Manuscript database

The corn flour composite fillers were prepared by blending corn flour with rubber latex, dried, and cryogenically ground into powders, which were then melt-blended with rubber polymers in an internal mixer to form composites with enhanced mechanical properties. The composites prepared with melt-blen...

PREPARATION OF COMPACTS MADE FROM URANIUM AND BERYLLIUM BY SINTERING

DOEpatents

Angier, R.P.

1961-04-11

A powder metallurgical method for making high-density compacts of uranium and beryllium is reported. Powdered UBe/sub 9/ and powdered Be are blended, compacted, and then sintered by rapidly heating to a temperature of approximately 1220 to 1280 deg C in an inert atmosphere.

Method of preparing thermal insulation for high temperature microwave sintering operations

DOEpatents

Holcombe, C.E.; Dykes, N.L.; Morrow, M.S.

1996-07-16

Superior microwave transparent thermal insulations for high temperature microwave sintering operations were prepared. One embodiment of the thermal insulation comprises granules of boron nitride coated with a very thin layer of glassy carbon made by preparing a glassy carbon precursor and blending it with boron nitride powder to form a mixture. The blended mixture is granulated to form a grit which is dried and heated to form the granules of boron nitride coated with a glassy carbon. Alternatively, grains of glassy carbon are coated with boron nitride by blending a mixture of a slurry comprising boron nitride, boric acid binder, and methyl alcohol with glassy carbon grains to form a blended mixture. The blended mixture is dried to form grains of glassy carbon coated with boron nitride. In addition, a physical mixture of boron nitride powder and glassy carbon grains has also been shown to be an excellent thermal insulation material for microwave processing and sintering. 1 fig.

Thermal insulation for high temperature microwave sintering operations and method thereof

DOEpatents

Holcombe, C.E.; Dykes, N.L.; Morrow, M.S.

1995-09-12

Superior microwave transparent thermal insulations for high temperature microwave sintering operations were prepared. One embodiment of the thermal insulation comprises granules of boron nitride coated with a very thin layer of glassy carbon made by preparing a glassy carbon precursor and blending it with boron nitride powder to form a mixture. The blended mixture is granulated to form a grit which is dried and heated to form the granules of boron nitride coated with a glassy carbon. Alternatively, grains of glassy carbon are coated with boron nitride by blending a mixture of a slurry comprising boron nitride, boric acid binder, and methyl alcohol with glassy carbon grains to form a blended mixture. The blended mixture is dried to form grains of glassy carbon coated with boron nitride. In addition, a physical mixture of boron nitride powder and glassy carbon grains has also been shown to be an excellent thermal insulation material for microwave processing and sintering. 1 fig.

Dry powder segregation and flowability: Experimental and numerical studies

NASA Astrophysics Data System (ADS)

Ely, David R.

Dry powder blending is a very important industrial and physical process used in the production of numerous pharmaceutical dosage forms such as tablets, capsules, and dry powder aerosols. Key aspects of this unit operation are process monitoring and control. Process control is particularly difficult due to the complexity of particle-particle interactions, which arise from the adhesion/cohesion characteristics of interfaces and morphological characteristics such as particle size, shape, and dispersity. The effects of such characteristics need to be understood in detail in order to correlate individual particle properties to bulk powder properties. The present dissertation numerically and experimentally quantifies the mixing process to rationalize particle-particle interactions. In particular, near infrared spectroscopy (NIRS) was used to non-invasively characterize in real-time the blending processes and thus investigate the dynamics of blending under different operating conditions. A novel image analysis technique was developed to quantify the scale of segregation from images obtained non-destructively via near infrared chemical imaging (NIR-CI). Although NIR-CI data acquisition times are too long for real-time data collection, NIR-CI has an advantage, in that it provides the spatial distribution of the drug. Therefore, NIRS and NIR-CI are complementary techniques for investigating the complex process of blending dry powders and assessing end-product quality. Additionally, the discrete element method was used to investigate the effect of powder cohesion on the packing fraction. Simulations indicated an exponential relationship between the random loose packing fraction and cohesive forces. Specifically, the packing fraction decreased asymptotically with increased ratio of cohesive force to particle weight. Thus, increasing this force ratio above a critical value has negligible impact on the packing fraction. Such result directly impacts the Hausner ratio flowability measurement, which is directly related to the packing fraction. Two commonly used tests were compared to assess their utility: the rotational split-cell shear cell test and the Hausner ratio. The Hausner ratio proved to be better suited for characterizing the flowability of unconsolidated powders than the splitring shear cell. Results demonstrate that the optimal flowability test depends on the powder properties and the environment under which flow will be induced.

Challenges in detecting magnesium stearate distribution in tablets.

PubMed

Lakio, Satu; Vajna, Balázs; Farkas, István; Salokangas, Henri; Marosi, György; Yliruusi, Jouko

2013-03-01

Magnesium stearate (MS) is the most commonly used lubricant in pharmaceutical industry. During blending, MS particles form a thin layer on the surfaces of the excipient and drug particles prohibiting the bonding from forming between the particles. This hydrophobic layer decreases the tensile strength of tablets and prevents water from penetrating into the tablet restraining the disintegration and dissolution of the tablets. Although overlubrication of the powder mass during MS blending is a well-known problem, the lubricant distribution in tablets has traditionally been challenging to measure. There is currently no adequate analytical method to investigate this phenomenon. In this study, the distribution of MS in microcrystalline cellulose (MCC) tablets was investigated using three different blending scales. The crushing strength of the tablets was used as a secondary response, as its decrease is known to result from the overlubrication. In addition, coating of the MCC particles by MS in intact tablets was detected using Raman microscopic mapping. MS blending was more efficient in larger scales. Raman imaging was successfully applied to characterize MS distribution in MCC tablets despite low concentration of MS. The Raman method can provide highly valuable visual information about the proceeding of the MS blending process. However, the measuring set-up has to be carefully planned to establish reliable and reproducible results.

Effects of Blended-Cement Paste Chemical Composition Changes on Some Strength Gains of Blended-Mortars

PubMed Central

Kirgiz, Mehmet Serkan

2014-01-01

Effects of chemical compositions changes of blended-cement pastes (BCPCCC) on some strength gains of blended cement mortars (BCMSG) were monitored in order to gain a better understanding for developments of hydration and strength of blended cements. Blended cements (BC) were prepared by blending of 5% gypsum and 6%, 20%, 21%, and 35% marble powder (MP) or 6%, 20%, 21%, and 35% brick powder (BP) for CEMI42.5N cement clinker and grinding these portions in ball mill at 30 (min). Pastes and mortars, containing the MP-BC and the BP-BC and the reference cement (RC) and tap water and standard mortar sand, were also mixed and they were cured within water until testing. Experiments included chemical compositions of pastes and compressive strengths (CS) and flexural strengths (FS) of mortars were determined at 7th-day, 28th-day, and 90th-day according to TS EN 196-2 and TS EN 196-1 present standards. Experimental results indicated that ups and downs of silica oxide (SiO2), sodium oxide (Na2O), and alkali at MP-BCPCC and continuously rising movement of silica oxide (SiO2) at BP-BCPCC positively influenced CS and FS of blended cement mortars (BCM) in comparison with reference mortars (RM) at whole cure days as MP up to 6% or BP up to 35% was blended for cement. PMID:24587737

Evaluation of the degree of mixing of combinations of dry syrup, powder, and fine granule products in consideration of particle size distribution using near infrared spectrometry.

PubMed

Yamamoto, Yoshihisa; Suzuki, Toyofumi; Matsumoto, Mika; Ohtani, Michiteru; Hayano, Shuichi; Fukami, Toshiro; Tomono, Kazuo

2012-01-01

We used near infrared (NIR) spectroscopy to evaluate the degree of mixing of blended dry syrup (DS) products whose particle sizes are not specified in the Revised 16th Edition of the Japanese Pharmacopoeia, and also evaluated the degree of mixing when powder products or fine granule products were added to DS products. The data obtained were used to investigate the relationship between the particle size distributions of the products studied and the degree of mixing. We found that the particle size distribution characteristics of the 15 DS products studied can be broadly classified into 5 types. Combinations of frequently prescribed products were selected to represent 4 of the 5 particle size distribution types and were blended with a mortar and pestle. The coefficient of variation (CV) decreased as the percent mass of Asverin® Dry Syrup 2% (Asverin-DS) increased in blends of Periactin® Powder 1% (Periactin) and Asverin-DS, indicating an improved degree of mixing (uniformity). In contrast, in blends of Periactin and Mucodyne® DS 33.3%, mixing a combination at a 1:1 mass ratio 40 times resulted in a CV of 20%. Other mixing frequencies and mass ratios resulted in a CV by 50% to 70%, indicating a very poor degree of mixing (poor uniformity). These results suggest that when combining different DSs, or a DS with a powder or fine granule product, the blending obtained with a mortar and pestle improves as the particle size distributions of the components approach each other and as the ranges of the distributions narrow.

9 CFR 590.544 - Spray process powder; definitions and requirements.

Code of Federal Regulations, 2012 CFR

2012-01-01

...-blended: Provided, That the blending is done in a room as provided in § 590.548 or in a closed blending system and in accordance with clean, sanitary practices and such procedures as may be prescribed by the... accomplished in a clean, sanitary manner and in accordance with such procedures as may be prescribed by the...

9 CFR 590.544 - Spray process powder; definitions and requirements.

Code of Federal Regulations, 2014 CFR

2014-01-01

...-blended: Provided, That the blending is done in a room as provided in § 590.548 or in a closed blending system and in accordance with clean, sanitary practices and such procedures as may be prescribed by the... accomplished in a clean, sanitary manner and in accordance with such procedures as may be prescribed by the...

9 CFR 590.544 - Spray process powder; definitions and requirements.

Code of Federal Regulations, 2011 CFR

2011-01-01

...-blended: Provided, That the blending is done in a room as provided in § 590.548 or in a closed blending system and in accordance with clean, sanitary practices and such procedures as may be prescribed by the... accomplished in a clean, sanitary manner and in accordance with such procedures as may be prescribed by the...

9 CFR 590.544 - Spray process powder; definitions and requirements.

Code of Federal Regulations, 2013 CFR

2013-01-01

...-blended: Provided, That the blending is done in a room as provided in § 590.548 or in a closed blending system and in accordance with clean, sanitary practices and such procedures as may be prescribed by the... accomplished in a clean, sanitary manner and in accordance with such procedures as may be prescribed by the...

Quantitation of active pharmaceutical ingredients and excipients in powder blends using designed multivariate calibration models by near-infrared spectroscopy.

PubMed

Li, Weiyong; Worosila, Gregory D

2005-05-13

This research note demonstrates the simultaneous quantitation of a pharmaceutical active ingredient and three excipients in a simulated powder blend containing acetaminophen, Prosolv and Crospovidone. An experimental design approach was used in generating a 5-level (%, w/w) calibration sample set that included 125 samples. The samples were prepared by weighing suitable amount of powders into separate 20-mL scintillation vials and were mixed manually. Partial least squares (PLS) regression was used in calibration model development. The models generated accurate results for quantitation of Crospovidone (at 5%, w/w) and magnesium stearate (at 0.5%, w/w). Further testing of the models demonstrated that the 2-level models were as effective as the 5-level ones, which reduced the calibration sample number to 50. The models had a small bias for quantitation of acetaminophen (at 30%, w/w) and Prosolv (at 64.5%, w/w) in the blend. The implication of the bias is discussed.

The influence of direct compression powder blend transfer method from the container to the tablet press on product critical quality attributes: a case study.

PubMed

Teżyk, Michał; Jakubowska, Emilia; Milczewska, Kasylda; Milanowski, Bartłomiej; Voelkel, Adam; Lulek, Janina

2017-06-01

The aim of this article is to compare the gravitational powder blend loading method to the tablet press and manual loading in terms of their influence on tablets' critical quality attributes (CQA). The results of the study can be of practical relevance to the pharmaceutical industry in the area of direct compression of low-dose formulations, which could be prone to content uniformity (CU) issues. In the preliminary study, particle size distribution (PSD) and surface energy of raw materials were determined using laser diffraction method and inverse gas chromatography, respectively. For trials purpose, a formulation containing two pharmaceutical ingredients (APIs) was used. Tablet samples were collected during the compression progress to analyze their CQAs, namely assay and CU. Results obtained during trials indicate that tested direct compression powder blend is sensitive to applied powder handling method. Mild increase in both APIs content was observed during manual scooping. Gravitational approach (based on discharge into the drum) resulted in a decrease in CU, which is connected to a more pronounced assay increase at the end of tableting than in the case of manual loading. The correct design of blend transfer over single unit processes is an important issue and should be investigated during the development phase since it may influence the final product CQAs. The manual scooping method, although simplistic, can be a temporary solution to improve the results of API's content and uniformity when compared to industrial gravitational transfer.

Vacuum Pressureless Sintering of Ti-6Al-4V Alloy with Full Densification and Forged-Like Mechanical Properties

NASA Astrophysics Data System (ADS)

Zhang, Ce; Lu, Boxin; Wang, Haiying; Guo, Zhimeng; Paley, Vladislav; Volinsky, Alex A.

2018-01-01

Ti-6Al-4V ingots with a nearly 100% density, fine and homogeneous basket-weave microstructure, and better comprehensive mechanical properties (UTS = 935 MPa, Y.S. = 865 MPa, El. = 15.8%), have been manufactured by vacuum pressureless sintering of blended elemental powders. Coarse TiH2 powder, Al powder (2, 20 μm), V powder, and Al-V master alloy powder were used as raw materials to produce different powder mixtures ( D 50 = 10 μm). Then, the compacts made by cold isostatic pressing were consolidated by different sintering curves. A detailed investigation of different as-sintered samples revealed that a higher density can be obtained by generating transient molten Al in the sintering process. Coarse Al powder and a rapid heating rate under the melting point of Al contribute to molten Al formation. The presence of temporary liquid phase changes the sintering mechanism, accelerating the sintering neck formation, improving sinterability of the powder mixtures. Density of 99.5% was achieved at 1150 °C, which is markedly lower than the sintering temperatures reported for conventional blended elemental powder metallurgy routes. In addition, low interstitial content, especially for oxygen (0.17 wt.%), is obtained by strict process control.

Applying Massively Parallel Kinetic Monte Carlo Methods to Simulate Grain Growth and Sintering in Powdered Metals

DTIC Science & Technology

2011-09-01

Structure Evolution During Sintering From [19]. ...................................20 Figure 10. Ising Model Configuration With Eight Nearest Neighbors...INTRODUCTION A. MOTIVATION The ability to fabricate structural components from metals with a fine (micron- sized), controlled grain size is one of the...hallmarks of modern, structural metallurgy. Powder metallurgy, in particular, consists of powder manufacture, powder blending, compacting, and sintering

Abrasion resistant coating and method of making the same

DOEpatents

Sordelet, Daniel J.; Besser, Matthew F.

2001-06-05

An abrasion resistant coating is created by adding a ductile phase to a brittle matrix phase during spray coating where an Al--Cu--Fe quasicrystalline phase (brittle matrix) and an FeAl intermetallic (ductile phase) are combined. This composite coating produces a coating mostly of quasicrystal phase and an inter-splat layer of the FeAl phase to help reduce porosity and cracking within the coating. Coatings are prepared by plasma spraying unblended and blended quasicrystal and intermetallic powders. The blended powders contain 1, 5, 10 and 20 volume percent of the intermetallic powders. The unblended powders are either 100 volume percent quasicrystalline or 100 volume percent intermetallic; these unblended powders were studied for comparison to the others. Sufficient ductile phase should be added to the brittle matrix to transform abrasive wear mode from brittle fracture to plastic deformation, while at the same time the hardness of the composite should not be reduced below that of the original brittle phase material.

Influence of metallic additives on manganese ferrites sintering

NASA Astrophysics Data System (ADS)

Shevelev, S. A.; Luchnikov, P. A.; Yarullina, A. R.

2018-01-01

Influence of cuprum nanopowder additive received by electric explosion on the process of manganese ferrites MgFe2O4 consolidating at thermal sintering was researched by dilatometry method. Cuprum nanopowder at a rate of 5 mass % was added into the original commercial-grade powder of manganese ferrite MgFe2O4. Powder mixture was numerously blended with screening for better blending before pressing. Powder compacts were formed by cold one-axle static pressing. It was proved that introduction of cuprum additive caused shrinkage increase at final heating stage. There was abnormal compact enlarging at sintering in the air at isothermal stage; the specified process was not observed in vacuum. This difference can be explained by changes in conditions of gaseous discharge from volume of pores.

To evaluate the effect of various magnesium stearate polymorphs using powder rheology and thermal analysis.

PubMed

Okoye, Patrick; Wu, Stephen H; Dave, Rutesh H

2012-12-01

The effects of magnesium stearate (MgSt) polymorphs-anhydrate (MgSt-A), monohydrate (MgSt-M), and dihydrate (MgSt-D)-on rheological properties of powders were evaluated using techniques such as atomic analysis and powder rheometry. Additional evaluation was conducted using thermal analysis, micromeritics, and tableting forces. In this study, binary ratios of neat MgSt polymorphs were employed as lubricants in powder blends containing acetaminophen (APAP), microcrystalline cellulose (MCC), and lactose monohydrate (LAC-M). Powder rheometry was studied using permeability, basic flow energy (BFE), density, and porosity analysis. Thermal conductivity and differential scanning calorimetric analysis of MgSt polymorphs were employed to elucidate MgSt effect on powder blends. The impact of MgSt polymorphs on compaction characteristics were analyzed via tablet compression forces. Finally, the distribution of atomized magnesium (Mg) ions as a function of intensity was evaluated using laser-induced breakdown spectroscopy (LIBS) on tablets. The results from LIBS analysis indicated the dependency of the MgSt polymorphic forms on the atomized Mg ion intensity, with higher Mg ion intensity suggesting higher lubricity index (i.e. greater propensity to over-lubricate). The results from lubricity index suggested the tendency of blends to over-lubricate based on the MgSt polymorphic forms. Finally, tableting forces suggested that MgSt-D and MgSt-A offered processing benefits such as lower ejection and compression forces, and that MgSt-M showed the most stable compression force in single or combined polymorphic ratios. These results suggested that the initial moisture content, crystal arrangement, intra- and inter-molecular packing of the polymorphs defined their effects on the rheology of lubricated powders.

Powder treatment process

DOEpatents

Weyand, J.D.

1988-02-09

Disclosed are: (1) a process comprising spray drying a powder-containing slurry, the slurry containing a powder constituent susceptible of oxidizing under the temperature conditions of the spray drying, while reducing the tendency for oxidation of the constituent by including as a liquid constituent of the slurry an organic liquid; (2) a process comprising spray drying a powder-containing slurry, the powder having been pretreated to reduce content of a powder constituent susceptible of oxidizing under the temperature conditions of the spray drying, the pretreating comprising heating the powder to react the constituent; and (3) a process comprising reacting ceramic powder, grinding the reacted powder, slurrying the ground powder, spray drying the slurried powder, and blending the dried powder with metal powder. 2 figs.

Powder treatment process

DOEpatents

Weyand, John D.

1988-01-01

(1) A process comprising spray drying a powder-containing slurry, the slurry containing a powder constituent susceptible of oxidizing under the temperature conditions of the spray drying, while reducing the tendency for oxidation of the constituent by including as a liquid constituent of the slurry an organic liquid; (2) a process comprising spray drying a powder-containing slurry, the powder having been pretreated to reduce content of a powder constituent susceptible of oxidizing under the temperature conditions of the spray drying, the pretreating comprising heating the powder to react the constituent; and (3) a process comprising reacting ceramic powder, grinding the reacted powder, slurrying the ground powder, spray drying the slurried powder, and blending the dried powder with metal powder.

Liquid coated melt-spun Nd-Fe-B powders for bonded magnets

NASA Astrophysics Data System (ADS)

Li, D.; Gaiffi, S.; Kirk, D.; Young, K.; Herchenroeder, J.; Berwald, T.

1999-04-01

The liquid coating (LC) has been employed to apply epoxy and lubricant over the surface of rapidly solidified Nd-Fe-B powder particles. The LC led to an improvement of physical and magnetic properties for the powders and magnets compared to the dry blending and the encapsulation methods. The LC powders have excellent flowability and can be used for bonded magnets requiring very close tolerances; further bonded magnets made using this powder posses higher strength.

Improvement of sticking in tablet compaction for tocopherol acetate.

PubMed

Sakata, Yukoh; Yamaguchi, Hiroyuki

2011-09-01

We have found that the addition of xylitol solution effectively improves the sticking observed in tablet compaction using a powder prescription including kneading mixtures comprising tocopherol acetate (TA)/Florite(®) RE (FLR) blends. The aim of the present study was to investigate the distribution states of TA and xylitol in kneaded mixtures comprising TA/FLR/xylitol blends and the particle states of these mixtures in order to derive an appropriate powder formulation for tablet compaction. Nitrogen gas adsorption analysis revealed that xylitol is distributed on the interparticle and intraparticle pores of FLR in the same manner as TA. Moreover, it was found that xylitol was distributed in an incomplete crystalline form because of its interaction with FLR particles in the kneaded mixtures comprising TA/FLR/xylitol blends. It was also observed that the surfaces of the particles of the kneaded mixtures comprising TA/FLR blends changed from rough to smooth because of kneading with xylitol. The occurrence of sticking can be prevented not only by the addition of xylitol but also by changing the particle states of TA/FLR/xylitol blends.

The influence of high shear mixing on ternary dry powder inhaler formulations.

PubMed

Hertel, Mats; Schwarz, Eugen; Kobler, Mirjam; Hauptstein, Sabine; Steckel, Hartwig; Scherließ, Regina

2017-12-20

The blending process is a key step in the production of dry powder inhaler formulations, but only little is known about the influence of process parameters. This is especially true for high shear blending of ternary formulations. For this reason, this study aims to investigate the influence of high shear mixing process parameters (mixing time and rotation speed) on the fine particle fraction (FPF) of ternary mixtures when using budesonide as model drug, two different carrier materials and two different mixing orders. Prolonged mixing time and higher rotation speeds led to lower FPFs, possibly due to higher press-on forces acting on the active pharmaceutical ingredients (API). In addition, a clear correlation between the energy consumption of the blender (the energy input into the blend) and the reduction of the FPF could be shown. Furthermore blending the carrier and the fines before adding the API was also found to be favorable. Copyright © 2017 Elsevier B.V. All rights reserved.

An efficient, maintenance free and approved method for spectroscopic control and monitoring of blend uniformity: The moving F-test.

PubMed

Besseling, Rut; Damen, Michiel; Tran, Thanh; Nguyen, Thanh; van den Dries, Kaspar; Oostra, Wim; Gerich, Ad

2015-10-10

Dry powder mixing is a wide spread Unit Operation in the Pharmaceutical industry. With the advent of in-line Near Infrared (NIR) Spectroscopy and Quality by Design principles, application of Process Analytical Technology to monitor Blend Uniformity (BU) is taking a more prominent role. Yet routine use of NIR for monitoring, let alone control of blending processes is not common in the industry, despite the improved process understanding and (cost) efficiency that it may offer. Method maintenance, robustness and translation to regulatory requirements have been important barriers to implement the method. This paper presents a qualitative NIR-BU method offering a convenient and compliant approach to apply BU control for routine operation and process understanding, without extensive calibration and method maintenance requirements. The method employs a moving F-test to detect the steady state of measured spectral variances and the endpoint of mixing. The fundamentals and performance characteristics of the method are first presented, followed by a description of the link to regulatory BU criteria, the method sensitivity and practical considerations. Applications in upscaling, tech transfer and commercial production are described, along with evaluation of the method performance by comparison with results from quantitative calibration models. A full application, in which end-point detection via the F-test controls the blending process of a low dose product, was successfully filed in Europe and Australia, implemented in commercial production and routinely used for about five years and more than 100 batches. Copyright © 2015 Elsevier B.V. All rights reserved.

Effects of Coating Materials and Processing Conditions on Flow Enhancement of Cohesive Acetaminophen Powders by High-Shear Processing With Pharmaceutical Lubricants.

PubMed

Wei, Guoguang; Mangal, Sharad; Denman, John; Gengenbach, Thomas; Lee Bonar, Kevin; Khan, Rubayat I; Qu, Li; Li, Tonglei; Zhou, Qi Tony

2017-10-01

This study has investigated the surface coating efficiency and powder flow improvement of a model cohesive acetaminophen powder by high-shear processing with pharmaceutical lubricants through 2 common equipment, conical comil and high-shear mixer. Effects of coating materials and processing parameters on powder flow and surface coating coverage were evaluated. Both Carr's index and shear cell data indicated that processing with the lubricants using comil or high-shear mixer substantially improved the flow of the cohesive acetaminophen powder. Flow improvement was most pronounced for those processed with 1% wt/wt magnesium stearate, from "cohesive" for the V-blended sample to "easy flowing" for the optimally coated sample. Qualitative and quantitative characterizations demonstrated a greater degree of surface coverage for high-shear mixing compared with comilling; nevertheless, flow properties of the samples at the corresponding optimized conditions were comparable between 2 techniques. Scanning electron microscopy images demonstrated different coating mechanisms with magnesium stearate or l-leucine (magnesium stearate forms a coating layer and leucine coating increases surface roughness). Furthermore, surface coating with hydrophobic magnesium stearate did not retard the dissolution kinetics of acetaminophen. Future studies are warranted to evaluate tableting behavior of such dry-coated pharmaceutical powders. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Analysis of the Influence of Starting Materials and Processing Conditions on the Properties of W/Cu Alloys.

PubMed

Montealegre-Meléndez, Isabel; Arévalo, Cristina; Perez-Soriano, Eva M; Neubauer, Erich; Rubio-Escudero, Cristina; Kitzmantel, Michael

2017-02-08

In this work, a study of the influence of the starting materials and the processing time used to develop W/Cu alloys is carried out. Regarding powder metallurgy as a promising fabrication route, the difficulties in producing W/Cu alloys motivated us to investigate the influential factors on the final properties of the most industrially demanding alloys: 85-W/15-Cu, 80-W/20-Cu, and 75-W/25-Cu alloys. Two different tungsten powders with large variation among their particle size-fine (W f ) and coarse (W c ) powders-were used for the preparation of W/Cu alloys. Three weight ratios of fine and coarse (W f :W c ) tungsten particles were analyzed. These powders were labelled as "tungsten bimodal powders". The powder blends were consolidated by rapid sinter pressing (RSP) at 900 °C and 150 MPa, and were thus sintered and compacted simultaneously. The elemental powders and W/Cu alloys were studied by optical microscopy (OM) and scanning electron microscopy (SEM). Thermal conductivity, hardness, and densification were measured. Results showed that the synthesis of W/Cu using bimodal tungsten powders significantly affects the final alloy properties. The higher the tungsten content, the more noticeable the effect of the bimodal powder. The best bimodal W powder was the blend with 10 wt % of fine tungsten particles (10-W f :90-W c ). These specimens present good values of densification and hardness, and higher values of thermal conductivity than other bimodal mixtures.

Hardness and wear analysis of Cu/Al2O3 composite for application in EDM electrode

NASA Astrophysics Data System (ADS)

Hussain, M. Z.; Khan, U.; Jangid, R.; Khan, S.

2018-02-01

Ceramic materials, like Aluminium Oxide (Al2O3), have high mechanical strength, high wear resistance, high temperature resistance and good chemical durability. Powder metallurgy processing is an adaptable method commonly used to fabricate composites because it is a simple method of composite preparation and has high efficiency in dispersing fine ceramic particles. In this research copper and novel material aluminium oxide/copper (Al2O3/Cu) composite has been fabricated for the application of electrode in Electro-Discharge Machine (EDM) using powder metallurgy technique. Al2O3 particles with different weight percentages (0, 1%, 3% and 5%) were reinforced into copper matrix using powder metallurgy technique. The powders were blended and compacted at a load of 100MPa to produce green compacts and sintered at a temperature of 574 °C. The effect of aluminium oxide content on mass density, Rockwell hardness and wear behaviour were investigated. Wear behaviour of the composites was investigated on Die-Sink EDM (Electro-Discharge Machine). It was found that wear rate is highly depending on hardness, mass density and green protective carbonate layer formation at the surface of the composite.

Denitrification of groundwater using PHBV blends in packed bed reactors and the microbial diversity.

PubMed

Chu, Libing; Wang, Jianlong

2016-07-01

In the present study, three kinds of biopolymers, PHBV, PHBV/starch and PHBV/bamboo powder (BP) blends were used as carbon source and biofilm carriers for denitrification in packed bed reactors to remove nitrate from groundwater. Results showed that a fast start-up was obtained in bioreactors filled with both PHBV/Starch and PHBV/BP blends without external inocula and it took more than 3 month for PHBV reactor to reach the same loading rate. The PHBV/BP packed reactor exhibited a better nitrate removal efficiency (87.4 ± 7.0%) and less adverse effects in nitrite accumulation and DOC release (below 0.5 mg NO2N L(-1) and 10.5 mg DOC L(-1) in the effluent) during stable operation. Pyrosequencing analysis demonstrated that bacteria belonging to genus Clostridium in phylum Firmicus, which play the primary role in degrading the biopolymers, are the most dominant (33-15% of the sequences). The predominant species in all samples is related to Clostridium crotonatovorans. All the identified 11 genera of denitrifying bacteria affiliated with phylum Proteobacteria and constituted 30-55% in the representative sequences. The PHBV/BP blend is economically attractive carbon source with good denitrification performance. Copyright © 2016 Elsevier Ltd. All rights reserved.

Improved properties of fine active pharmaceutical ingredient powder blends and tablets at high drug loading via dry particle coating.

PubMed

Kunnath, Kuriakose; Huang, Zhonghui; Chen, Liang; Zheng, Kai; Davé, Rajesh

2018-05-30

It has been shown that dry coating cohesive active pharmaceutical ingredients (APIs) with nano-silica can improve packing and flow of their blends, facilitating high speed direct compression tableting. This paper examines the broader scope and generality of previous work by examining three fine APIs; micronized Acetaminophen (mAPAP), coarse Acetaminophen (cAPAP) and micronized Ibuprofen (mIBU), and considers dry coating with both hydrophobic or hydrophilic nano-silica to examine the effect not only on packing density and flow of their blends, but also dissolution and tensile strength of their tablets. The impact of the excipient size on blend and tablet properties are also investigated, indicating blend flow is most improved when matching API particle size with excipient particle size. In all cases where the API is dry coated, the blend packing and flow improve, so as to suggest such high drug loaded blends could enable direct compression. Using dry coated API along with finer excipients in blends lead to improved hardness of the corresponding tablets. Interestingly, dissolution profiles show dry coated API tablets generally have faster dissolution rates, regardless of silica hydrophilicity, suggesting API powder deagglomeration via nano-silica coating plays a crucial role. The most significant conclusion is that, although there are differences in properties of blends that depend on the API, hydrophobic or hydrophilic nano-silica coating, as well as large or fine excipients, in all cases, dry coating of APIs significantly improves the possibility of using the specific blend at high drug loading in direct compression tableting. Copyright © 2018 Elsevier B.V. All rights reserved.

Powder Processing of Amorphous Tungsten-bearing Alloys and Composites

DTIC Science & Technology

2015-03-01

8725 John J. Kingman Road, MS-6201 Fort Belvoir, VA 22060-6201 T E C H N IC A L R E P O R T DTRA-TR-14-73 Powder Processing of Amorphous Tungsten...Technology, Boise State University, Army Research Laboratory Project Title: Powder Processing of Amorphous Tungsten-bearing Alloys and Composites...Our year 3 tasks, as laid out in the project proposal, were to 1) Consolidate amorphous or nanocrystalline powder blends 2) Mechanical testing

Investigation into the use of microwave sensors to monitor particulate manufacturing processes

NASA Astrophysics Data System (ADS)

Austin, John Samuel, III

Knowledge of a material's properties in-line during manufacture is of critical importance to many industries, including the pharmaceutical industry, and can be used for either process or quality control. Different microwave sensor configurations were tested to determine both the moisture content and the bulk density in pharmaceutical powders during processing on-line. Although these parameters can significantly affect a material's flowability, compressibility, and cohesivity, in the presence of blends, the picture is incomplete. Due to the ease with which particulate blends tend to segregate, blend uniformity and chemical composition are two critical parameters in nearly all solids manufacturing industries. The prevailing wisdom has been that microwave sensors are not capable of or sensitive enough to measure the relative concentrations of components in a blend. Consequently, it is common to turn to near infrared sensing to determine material composition on-line. In this study, a novel microwave sensor was designed and utilized to determine, separately, the concentrations of different components in a blend of pharmaceutical powders. This custom microwave sensor was shown to have comparable accuracy to the state-of-the-art for both chemical composition and moisture content determination.

Preparing composite materials from matrices of processable aromatic polyimide thermoplastic blends

NASA Technical Reports Server (NTRS)

Johnston, Norman J. (Inventor); St.clair, Terry L. (Inventor); Baucom, Robert M. (Inventor); Gleason, John R. (Inventor)

1991-01-01

Composite materials with matrices of tough, thermoplastic aromatic polyimides are obtained by blending semi-crystalline polyimide powders with polyamic acid solutions to form slurries, which are used in turn to prepare prepregs, the consolidation of which into finished composites is characterized by excellent melt flow during processing.

Investigation of the potential for direct compaction of a fine ibuprofen powder dry-coated with magnesium stearate.

PubMed

Qu, Li; Zhou, Qi Tony; Gengenbach, Thomas; Denman, John A; Stewart, Peter J; Hapgood, Karen P; Gamlen, Michael; Morton, David A V

2015-05-01

Intensive dry powder coating (mechanofusion) with tablet lubricants has previously been shown to give substantial powder flow improvement. This study explores whether the mechanofusion of magnesium stearate (MgSt), on a fine drug powder can substantially improve flow, without preventing the powder from being directly compacted into tablets. A fine ibuprofen powder, which is both cohesive and possesses a low-melting point, was dry coated via mechanofusion with between 0.1% and 5% (w/w) MgSt. Traditional low-shear blending was also employed as a comparison. No significant difference in particle size or shape was measured following mechanofusion. For the low-shear blended powders, only marginal improvement in flowability was obtained. However, after mechanofusion, substantial improvements in the flow properties were demonstrated. Both XPS and ToF-SIMS demonstrated high degrees of a nano-scale coating coverage of MgSt on the particle surfaces from optimized mechanofusion. The study showed that robust tablets were produced from the selected mechanofused powders, at high-dose concentration and tablet tensile strength was further optimized via addition of a Polyvinylpyrrolidone (PVP) binder (10% w/w). The tablets with the mechanofused powder (with or without PVP) also exhibited significantly lower ejection stress than those made of the raw powder, demonstrating good lubrication. Surprisingly, the release rate of drug from the tablets made with the mechanofused powder was not retarded. This is the first study to demonstrate such a single-step dry coating of model drug with MgSt, with promising flow improvement, flow-aid and lubrication effects, tabletability and also non-inhibited dissolution rate.

Facile and rapid auto-combustion synthesis of nano-porous γ-Al2O3 by application of hexamethylenetetramine in fuel composition

NASA Astrophysics Data System (ADS)

Salem, Shiva; Salem, Amin; Parni, Mohammad Hosein; Jafarizad, Abbas

2018-06-01

In this article, urea, glycine and hexamethylenetetramine were blended in accordance with the mixture design algorithm to prepare γ-Al2O3 by auto-combustion technique. Aluminum nitrate was then mixed with the stoichiometric contents of prepared fuel solutions to obtain gel systems. The gels exhibited a typical self-propagating combustion behavior at low temperature, directly resulting amorphous materials. The precursors were calcined at various temperatures ranging from 700 to 900 °C. The treated powders were evaluated by determining the methylene blue (MB) adsorption efficiency. The production condition to obtain γ-Al2O3 with maximum surface area depends on fuel composition and calcination temperature. The alumina powder fabricated by this procedure was uniformly distributed and contains nano-sized secondary particles with diameter about 10-30 nm in which the average pore size is 3.2 nm induced large surface area, 240 m2g-1. The employment of hexamethylenetetramine provides a potential for synthesis of γ-Al2O3 at lower temperature, 700 °C, with maximum MB removal efficiency.

Identification of a gamma-irradiated ingredient (garlic powder) in Korean barbeque sauce by thermoluminescence analysis.

PubMed

Ahn, Jae-Jun; Akram, Kashif; Lee, Jeongeun; Kim, Kyong-Su; Kwon, Joong-Ho

2012-04-01

Thermoluminescence (TL) analysis was applied to identify gamma-irradiated garlic powder in Korean barbeque sauce before and after pasteurization (85 °C, 30 min), when blended in different ratios (1%, 3%, and 5%). The sauce sample with nonirradiated garlic powder gave a background glow curve. However, the sample blended with irradiated ingredient (1 and 10 kGy) showed typical TL glow curves at temperatures of 150 to 200 °C. The identification properties of sauce samples were more influenced by blending ratios than by irradiation doses, showing that 3% and 5% added samples produced glow curves at 150 to 250 °C. After pasteurization of the samples containing the irradiated ingredient, TL glow intensity decreased but did not change its shape or temperature range. As a result, the pasteurization of Barbeque sauces containing irradiated ingredients had reduced TL glow intensity, but the shape and temperature range of glow curve were still able to provide information required for confirming irradiation treatment. To monitor the irradiated food in international market, thermoluminescence (TL) analysis is considered most promising identification technique because of its sensitivity and long-term stability. In this study the applicability of TL analysis to detect an irradiated ingredient (garlic powder) added in low quantity to a food matrix (sauce) was investigated. The effect of processing (pasteurization) on TL results was also evaluated. © 2012 Institute of Food Technologists®

Electrochemical cell with powdered electrically insulative material as a separator

DOEpatents

Mathers, James P.; Olszanski, Theodore W.; Boquist, Carl W.

1978-01-01

A secondary electrochemical cell includes electrodes separated by a layer of electrically insulative powder. The powder includes refractory materials selected from the oxides and nitrides of metals and metaloids. The powdered refractory material, blended with electrolyte particles, can be compacted in layers with electrode materials to form an integral electrode structure or separately assembled into the cell. The assembled cell is heated to operating temperature leaving porous layers of electrically insulative, refractory particles, containing molten electrolyte between the electrodes.

Method of preparing a powdered, electrically insulative separator for use in an electrochemical cell

DOEpatents

Cooper, Tom O.; Miller, William E.

1978-01-01

A secondary electrochemical cell includes electrodes separated by a layer of electrically insulative powder. The powder includes refractory materials selected from the oxides and nitrides of metals and metaloids. The powdered refractory material, blended with electrolyte particles, is compacted as layers onto an electrode to form an integral electrode structure and assembled into the cell. The assembled cell is heated to its operating temperature leaving porous layers of electrically insulative, refractory particles, containing molten electrolyte between the electrodes.

Characterization of mutagenic activity in grain-based coffee-substitute blends and instant coffees

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

Johansson, M.A.E.; Knize, M.G.; Felton, J.S.

1994-06-01

Several grain-based coffee-substitute blends and instant coffees showed a mutagenic response in the Ames/Salmonella test using TA98, YG1024 and YG1O29 with metabolic activation. The beverage powders contained 150 to 500 TA98 and 1150 to 4050 YG1024 revertant colonies/gram, respectively. The mutagenic activity in the beverage powders was shown to be stable to heat and the products varied in resistance to acid nitrite treatment. Characterization of the mutagenic activity, using HPLC-and the Ames test of the collected fractions, showed the coffee-substitutes and instant coffees contain several mutagenic compounds, which are most likely aromatic amines.

Process Of Bonding Copper And Tungsten

DOEpatents

Slattery, Kevin T.; Driemeyer, Daniel E.; Davis, John W.

2000-07-18

Process for bonding a copper substrate to a tungsten substrate by providing a thin metallic adhesion promoting film bonded to a tungsten substrate and a functionally graded material (FGM) interlayer bonding the thin metallic adhesion promoting film to the copper substrate. The FGM interlayer is formed by sintering a stack of individual copper and tungsten powder blend layers having progressively higher copper content/tungsten content, by volume, ratio values in successive powder blend layers in a lineal direction extending from the tungsten substrate towards the copper substrate. The resulting copper to tungsten joint well accommodates the difference in the coefficient of thermal expansion of the materials.

Studies of Particle Packings in Mixtures of Pharmaceutical Excipients

NASA Astrophysics Data System (ADS)

Bentham, Craig; Dutt, Meenakshi; Hancock, Bruno; Elliott, James

2005-03-01

Pharmaceutical powder blends used to generate tablets are complex multicomponent mixtures of the drug powder and excipients which facilitate the delivery of the required drug. The individual constituents of these blends can be noncohesive and cohesive powders. We study the geometric and mechanical characteristics of idealized mixtures of excipient particle packings, for a small but representative number of dry noncohesive particles, generated via gravitational compaction followed by uniaxial compaction. We discuss particle packings in 2- and 3- component mixtures of microcrystalline cellulose (MCC) & lactose and MCC, starch & lactose, respectively. We have computed the evolution of the force and stress distributions in monodisperse and polydisperse mixtures comprised of equal parts of each excipient; comparisons are made with results for particles packings of pure blends of MCC and lactose. We also compute the stress-strain relations for these mixtures. In order to obtain insight into details of the particle packings, we calculate the coordination number, packing fraction, radial distribution functions and contact angle distributions for the various mixtures. The numerical experiments have been performed on spheroidal idealizations of the excipient grains using Discrete Element Method simulations (Dutt et al., 2004 to be published).

Effect of strain rate on mechanical properties of melt-processed soy flour composite filler and styrene-butadiene blends

USDA-ARS?s Scientific Manuscript database

Polymer composites were prepared by melt-mixing polymer and soy flour composite fillers in an internal mixer. Soy flour composite fillers were prepared by blending aqueous dispersion of soy flour with styrene-butadiene rubber latex, dried, and cryogenically ground into powders. Upon crosslinking, th...

Quality-by-design (QbD): effects of testing parameters and formulation variables on the segregation tendency of pharmaceutical powder measured by the ASTM D 6940-04 segregation tester.

PubMed

Xie, Lin; Wu, Huiquan; Shen, Meiyu; Augsburger, Larry L; Lyon, Robbe C; Khan, Mansoor A; Hussain, Ajaz S; Hoag, Stephen W

2008-10-01

The objective of this study was to examine the effects of testing parameters and formulation variables on the segregation tendency of pharmaceutical powders measured by the ASTM D 6940-04 segregation tester using design of experiments (DOE) approaches. The test blends consisted of 4% aspirin (ASP) and 96% microcrystalline cellulose (MCC) with and without magnesium stearate (MgS). The segregation tendency of a blend was determined by measuring the last/first (L/F) ratio, the ratio of aspirin concentrations between the first and last samples discharged from the tester. A 2(2) factorial design was used to determine the effects of measurement parameters [amount of material loaded (W), number of segregation cycles] with number of replicates 6. ANOVA showed that W was a critical parameter for segregation testing. The L/F value deviated further from 1 (greater segregation tendency) with increasing W. A 2(3) full factorial design was used to assess the effects of formulation variables: grade of ASP (unmilled, milled), grade of MCC, and amount of lubricant, MgS. MLR and ANOVA showed that the grade of ASP was the main effect contributing to segregation tendency. Principal Component Regression Analysis established a correlation between L/F and the physical properties of the blend related to ASP and MCC, the ASP/MCC particle size ratio (PSR) and powder cohesion. The physical properties of the blend related to density and flow were not influenced by the grade of ASP and were not related to the segregation tendency of the blend. The direct relationship between L/F and PSR was determined by univariate analysis. Segregation tendency increased as the ASP to MCC particle size increased. This study highlighted critical test parameters for segregation testing and identified critical physical properties of the blends that influence segregation tendency. (c) 2008 Wiley-Liss, Inc. and the American Pharmacists Association

Production of crispy bread snacks containing chicken meat and chicken meat powder.

PubMed

Cakmak, Hulya; Altinel, Burak; Kumcuoglu, Seher; Kisla, Duygu; Tavman, Sebnem

2016-01-01

Chicken meat in two different forms (chicken meat and chicken meat powder) were added into white flour and whole wheat blend baguette bread formulations for protein enrichment and finally developing new and healthy snacks. The chicken meat and powder levels were 10% for white flour baguette, and 15% for whole wheat blend. The dried baguette samples were packaged under 100% N2, and physical, chemical, microbiological and sensorial properties were evaluated during 3 months of storage. Protein content of chicken meat powder added samples were found statistically higher than chicken meat added samples. Hardness of the snacks was significantly affected from type of chicken meat, such as values were higher for chicken meat added samples than chicken meat powder added samples. Lipid oxidation of the snacks was determined by TBA analysis, and TBA value for whole wheat mixture snack with 15% of chicken meat was the highest among all during storage. The highest overall acceptance score was obtained from white flour snack with 10% chicken meat. There was no coliform bacteria detected during storage and the results of yeast-mold count and aerobic plate count of snacks remained between the quantitative ranges.

Analysis of the Influence of Starting Materials and Processing Conditions on the Properties of W/Cu Alloys

PubMed Central

Montealegre-Meléndez, Isabel; Arévalo, Cristina; Perez-Soriano, Eva M.; Neubauer, Erich; Rubio-Escudero, Cristina; Kitzmantel, Michael

2017-01-01

In this work, a study of the influence of the starting materials and the processing time used to develop W/Cu alloys is carried out. Regarding powder metallurgy as a promising fabrication route, the difficulties in producing W/Cu alloys motivated us to investigate the influential factors on the final properties of the most industrially demanding alloys: 85-W/15-Cu, 80-W/20-Cu, and 75-W/25-Cu alloys. Two different tungsten powders with large variation among their particle size—fine (Wf) and coarse (Wc) powders—were used for the preparation of W/Cu alloys. Three weight ratios of fine and coarse (Wf:Wc) tungsten particles were analyzed. These powders were labelled as “tungsten bimodal powders”. The powder blends were consolidated by rapid sinter pressing (RSP) at 900 °C and 150 MPa, and were thus sintered and compacted simultaneously. The elemental powders and W/Cu alloys were studied by optical microscopy (OM) and scanning electron microscopy (SEM). Thermal conductivity, hardness, and densification were measured. Results showed that the synthesis of W/Cu using bimodal tungsten powders significantly affects the final alloy properties. The higher the tungsten content, the more noticeable the effect of the bimodal powder. The best bimodal W powder was the blend with 10 wt % of fine tungsten particles (10-Wf:90-Wc). These specimens present good values of densification and hardness, and higher values of thermal conductivity than other bimodal mixtures. PMID:28772502

Process for making a ceramic composition for immobilization of actinides

DOEpatents

Ebbinghaus, Bartley B.; Van Konynenburg, Richard A.; Vance, Eric R.; Stewart, Martin W.; Walls, Philip A.; Brummond, William Allen; Armantrout, Guy A.; Herman, Connie Cicero; Hobson, Beverly F.; Herman, David Thomas; Curtis, Paul G.; Farmer, Joseph

2001-01-01

Disclosed is a process for making a ceramic composition for the immobilization of actinides, particularly uranium and plutonium. The ceramic is a titanate material comprising pyrochlore, brannerite and rutile. The process comprises oxidizing the actinides, milling the oxides to a powder, blending them with ceramic precursors, cold pressing the blend and sintering the pressed material.

Experimental Evaluation and Comparison of Thermal Conductivity of High-Voltage Insulation Materials for Vacuum Electronic Devices

NASA Astrophysics Data System (ADS)

Suresh, C.; Srikrishna, P.

2017-07-01

Vacuum electronic devices operate with very high voltage differences between their sub-assemblies which are separated by very small distances. These devices also emit large amounts of heat that needs to be dissipated. Hence, there exists a requirement for high-voltage insulators with good thermal conductivity for voltage isolation and efficient heat dissipation. However, these voltage insulators are generally poor conductors of heat. In the present work, an effort has been made to obtain good high-voltage insulation materials with substantial improvement in their thermal conductivity. New mixtures of composites were formed by blending varying percentages (by volumes) of aluminum nitride powders with that of neat room-temperature vulcanizing (RTV) silicone elastomer compound. In this work, a thermal conductivity test setup has been devised for the quantification of the thermal conductivity of the insulators. The thermal conductivities and high-voltage isolation capabilities of various blended composites were quantified and were compared with that of neat RTV to evaluate the relative improvement.

Characterization of irradiated blends of alpha-tocopherol and UHMWPE.

PubMed

Oral, Ebru; Greenbaum, Evan S; Malhi, Arnaz S; Harris, William H; Muratoglu, Orhun K

2005-11-01

Adhesive/abrasive wear in ultra-high molecular weight polyethylene (UHMWPE) has been minimized by radiation cross-linking. Irradiation is followed by melting to eliminate residual free radicals and avoid long-term oxidative embrittlement. However, post-irradiation melting reduces the crystallinity of the polymer and hence its strength and fatigue resistance. We proposed an alternative to post-irradiation melting to be the incorporation of the antioxidant alpha-tocopherol into UHMWPE prior to consolidation. alpha-Tocopherol is known to react with oxygen and oxidized lipids, stabilizing them against further oxidative degradation reactions. We blended GUR 1050 UHMWPE resin powder with alpha-tocopherol at 0.1 and 0.3 wt% and consolidated these blends. Then we gamma-irradiated these blends to 100-kGy. We characterized the effect of alpha-tocopherol on the cross-linking efficiency, oxidative stability, wear behavior and mechanical properties of the blends. (I) The cross-link density of virgin, 0.1 and 0.3 wt% alpha-tocopherol blended, 100-kGy irradiated UHMWPEs were 175+/-19, 146+/-4 and 93+/-4 mol/m3, respectively. (II) Maximum oxidation indices for 100-kGy irradiated UHMWPE previously blended with 0, 0.1 and 0.3 wt% alpha-tocopherol that were subjected to accelerated aging at 80 degrees C in air for 5 weeks were 3.32, 0.09, and 0.05, respectively. (III) The pin-on-disc wear rates of 100-kGy irradiated UHMWPE previously blended with 0.1 and 0.3 wt% alpha-tocopherol that were subjected to accelerated aging at 80 degrees C in air for 5 weeks were 2.10+/-0.17 and 5.01+/-0.76 mg/million cycles, respectively. (IV) Both accelerated aged, alpha-tocopherol-blended 100-kGy irradiated UHMWPEs showed higher ultimate tensile strength, higher yield strength, and lower elastic modulus when compared to 100-kGy irradiated, virgin UHMWPE. These results showed that alpha-tocopherol-blended 100-kGy irradiated UHMWPEs were not cross-linked to the same extent as the 100-kGy irradiated, virgin UHMWPE.

Physicochemical and Thermal Properties of Extruded Instant Functional Rice Porridge Powder as Affected by the Addition of Soybean or Mung Bean.

PubMed

Mayachiew, Pornpimon; Charunuch, Chulaluck; Devahastin, Sakamon

2015-12-01

Legumes contain protein, micronutrients, and bioactive compounds, which provide various health benefits. In this study, soybean or mung bean was mixed in rice flour to produce by extrusion instant functional legume-rice porridge powder. The effects of the type and percentage (10%, 20%, or 30%, w/w) of legumes on the expansion ratio of the extrudates were first evaluated. Amino acid composition, color, and selected physicochemical (bulk density, water absorption index, and water solubility index), thermal (onset temperature, peak temperature, and transition enthalpy), and pasting (peak viscosity, trough viscosity, and final viscosity) properties of the powder were determined. The crystalline structure and formation of amylose-lipid complexes and the total phenolics content (TPC) and antioxidant activity of the powder were also measured. Soybean-blended porridge powder exhibited higher TPC, 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity, ferric reducing antioxidant power, amino acid, and fat contents than the mung bean-blended porridge powder. Incorporating either legume affected the product properties by decreasing the lightness and bulk density, while increasing the greenness and yellowness and the peak temperature and transition enthalpy. Expansion capacity of the extrudates increased with percentage of mung bean in the mixture but decreased as the percentage of soybean increased. Amylose-lipid complexes formation was confirmed by X-ray diffraction analysis results. Addition of soybean or mung bean resulted in significant pasting property changes of the porridge powder. © 2015 Institute of Food Technologists®

Processable Aromatic Polyimide Thermoplastic Blends

NASA Technical Reports Server (NTRS)

Baucom, Robert M; Johnston, Norman J.; St. Clair, Terry L.; Nelson, James B.; Gleason, John R.; Proctor, K. Mason

1988-01-01

Method developed for preparing readily-processable thermoplastic polyimides by blending linear, high-molecular-weight, polyimic acid solutions in ether solvents with ultrafine, semicrystalline, thermoplastic polyimide powders. Slurries formed used to make prepregs. Consolidation of prepregs into finsihed composites characterized by excellent melt flow during processing. Applied to film, fiber, fabric, metal, polymer, or composite surfaces. Used to make various stable slurries from which prepregs prepared.

The use of whey or skimmed milk powder in fortified blended foods for vulnerable groups.

PubMed

Hoppe, Camilla; Andersen, Gregers S; Jacobsen, Stine; Mølgaard, Christian; Friis, Henrik; Sangild, Per T; Michaelsen, Kim F

2008-01-01

Fortified blended foods (FBF), especially corn soy blend, are used as food aid for millions of people worldwide, especially malnourished individuals and vulnerable groups. There are only a few studies evaluating the effect of FBF on health outcomes, and the potential negative effect of antinutrients has not been examined. Different lines of evidence suggest that dairy proteins have beneficial effects on vulnerable groups. Here we review the evidence on the effects of adding whey or skimmed milk powder to FBF used for malnourished infants and young children or people living with HIV or AIDS. Adding whey or skimmed milk powder to FBF improves the protein quality, allowing a reduction in total amount of protein, which could have potential metabolic advantages. It also allows for a reduced content of soy and cereal and thereby a reduction of potential antinutrients. It is possible that adding milk could improve weight gain, linear growth, and recovery from malnutrition, but this needs to be confirmed. Bioactive factors in whey might have beneficial effects on the immune system and muscle synthesis, but evidence from vulnerable groups is lacking. Milk proteins will improve flavor, which is important for acceptability in vulnerable groups. The most important disadvantage is a considerable increase in price. Adding 10-15% milk powder would double the price, which means that such a product should be used only in well-defined vulnerable groups with special needs. The potential beneficial effects of adding milk protein and lack of evidence in vulnerable groups call for randomized intervention studies.

Method of preparing porous, rigid ceramic separators for an electrochemical cell

DOEpatents

Bandyopadhyay, Gautam; Dusek, Joseph T.

1981-01-01

Porous, rigid separators for electrochemical cells are prepared by first calcining particles of ceramic material at temperatures above about 1200.degree. C. for a sufficient period of time to reduce the sinterability of the particles. A ceramic powder that has not been calcined is blended with the original powder to control the porosity of the completed separator. The ceramic blend is then pressed into a sheet of the desired shape and sintered at a temperature somewhat lower than the calcination temperature. Separator sheets of about 1 to 2.5 mm thickness and 30 to 70% porosity can be prepared by this technique. Ceramics such as yttria, magnesium oxide and magnesium-aluminum oxide have advantageously been used to form separators by this method.

Comparative study of methods to measure the density of Cementious powders

PubMed Central

Helsel, Michelle A.; Bentz, Dale

2016-01-01

The accurate measurement of the density of hydraulic cement has an essential role in the determination of concrete mixture proportions. As more supplementary cementitious materials (SCM), such as fly ash, and slag, or cement replacements materials such as limestone and calcium carbonate are used in blended cements, knowledge of the density of each powder or of the blended cement would allow a more accurate calculation of the proportions of a concrete mixture by volume instead of by mass. The current ASTM standard for measuring cement density is the “Test Method for Density of Hydraulic Cements” (ASTM C188-14), which utilizes a liquid displacement method to measure the volume of the cement. This paper will examine advantageous modifications of the current ASTM test, by alcohol substitutions for kerosene. In addition, a gas (helium) pycnometry method is evaluated as a possible alternative to the current standard. The described techniques will be compared to determine the most precise and reproducible method for measuring the density of hydraulic cements and other powders. PMID:27099404

Development of a Power Metallurgy Superalloy for Use at 1800-2000 F (980-1090 C)

NASA Technical Reports Server (NTRS)

Kortovich, C. S.

1973-01-01

A program was conducted to develop a powder metallurgy nickel-base superalloy for 1800-2000 F (980-1090 C) temperature applications. The feasibility of a unique concept for alloying carbon into a superalloy powder matrix and achieving both grain growth and a discrete particle grain boundary carbide precipitation was demonstrated. The process consisted of blending metastable carbides with a carbon free base alloy and consolidating this blend by hot extrusion. This was followed by heat treatment to grow a desired ASTM No. 2-3 grain size and to solution the metastable carbides to allow precipitation of discrete particle grain boundary carbides during subsequent aging heat treatments. The best alloy developed during this program was hydrogen-atomized, thermal-mechanically processed, modified MAR-M246 base alloy plus VC (0.28 w/o C). Although below those for cast MAR-M246, the mechanical properties exhibited by this alloy represent the best combination offered by conventional powder metallurgy processing to date.

Comparative study of methods to measure the density of Cementious powders.

PubMed

Helsel, Michelle A; Ferraris, Chiara F; Bentz, Dale

2016-11-01

The accurate measurement of the density of hydraulic cement has an essential role in the determination of concrete mixture proportions. As more supplementary cementitious materials (SCM), such as fly ash, and slag, or cement replacements materials such as limestone and calcium carbonate are used in blended cements, knowledge of the density of each powder or of the blended cement would allow a more accurate calculation of the proportions of a concrete mixture by volume instead of by mass. The current ASTM standard for measuring cement density is the "Test Method for Density of Hydraulic Cements" (ASTM C188-14), which utilizes a liquid displacement method to measure the volume of the cement. This paper will examine advantageous modifications of the current ASTM test, by alcohol substitutions for kerosene. In addition, a gas (helium) pycnometry method is evaluated as a possible alternative to the current standard. The described techniques will be compared to determine the most precise and reproducible method for measuring the density of hydraulic cements and other powders.

THE RESEARCH ON THERMAL PROPERTIES AND HYDROPHOBILITY OF THE NATIVE STARCH/HYDROLYSIS STARCH BLENDS WITH TREATED CaCO{sub 3} POWDER

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

Liu, C.-I; Huang, C.-Y.

In this research, hydrolysis starch was added into the starch blends to study the thermal properties. The enthalpy of blends had a significant decrease to 109J/g as content of treated CaCO{sub 3} increased to 5wt%. The modified starch was degraded slightly to produce glucose in the hydrolysis treatment. The amount of glucose in native starch and hydrolysis starch was 0.09 {mu}mol and 0.14 {mu}mol by the DNS measurement. Moreover, CaCO{sub 3} treated with titanium coupling agent was also added to improve miscibility and hydrophobility in the starch blends. The contact angle of the blends increased from 60 deg. to 95more » deg. when 15wt% treated CaCO{sub 3} was added. Treated CaCO{sub 3} was confirmed to improve the hydrophobility of starch blends effectively.« less

Dry powder aerosols generated by standardized entrainment tubes from alternative sugar blends: 3. Trehalose dihydrate and D-mannitol carriers.

PubMed

Mansour, Heidi M; Xu, Zhen; Hickey, Anthony J

2010-08-01

The relationship between physicochemical properties of drug/carrier blends and aerosol drug powder delivery was evaluated. Four pulmonary drugs each representing the major pulmonary therapeutic classes and with a different pharmacological action were employed. Specifically, the four pulmonary drugs were albuterol sulfate, ipratropium bromide monohydrate, disodium cromoglycate, and fluticasone propionate. The two carrier sugars, each representing a different sugar class, were D-mannitol and trehalose dihydrate. Dry powder aerosols (2%, w/w, drug in carrier) delivered using standardized entrainment tubes (SETs) were characterized by twin-stage liquid impinger. The fine particle fraction (FPF) was correlated with SET shear stress, tau(s), and the maximum fine particle fraction (FPF(max)) was correlated with a deaggregation constant, k(d), by using a powder aerosol deaggregation equation (PADE) by nonlinear and linear regression analyses applied to pharmaceutical inhalation aerosol systems in the solid state. For the four pulmonary drugs representing the major pulmonary therapeutic classes and two chemically distinct pulmonary sugar carriers (non-lactose types) aerosolized with SETs having well-defined shear stress values, excellent correlation and predictive relationships were demonstrated for the novel and rigorous application of PADE for dry powder inhalation aerosol dispersion within a well-defined shear stress range, in the context of pulmonary drug/sugar carrier physicochemical and interfacial properties. (c) 2010 Wiley-Liss, Inc. and the American Pharmacists Association

Method of preparing porous, rigid ceramic separators for an electrochemical cell. [Patent application

DOEpatents

Bandyopadhyay, G.; Dusek, J.T.

Porous, rigid separators for electrochemical cells are prepared by first calcining particles of ceramic material at temperatures above about 1200/sup 0/C for a sufficient period of time to reduce the sinterability of the particles. A ceramic powder that has not been calcined is blended with the original powder to control the porosity of the completed separator. The ceramic blend is then pressed into a sheet of the desired shape and sintered at a temperature somewhat lower than the calcination temperature. Separator sheets of about 1 to 2.5 mm thickness and 30 to 70% porosity can be prepared by this technique. Ceramics such as yttria, magnesium oxide, and magnesium-aluminium oxide have advantageously been used to form separators by this method.

Incorporation of carrot pomace powder in wheat flour: effect on flour, dough and cookie characteristics.

PubMed

Ahmad, Mukhtar; Wani, Touseef Ahmed; Wani, S M; Masoodi, F A; Gani, Adil

2016-10-01

Carrot pomace powder (CPP) of 72 and 120 mesh sizes was incorporated in wheat flour at 10, 15 and 20 % level and its impact on flour, dough and cookie characteristics was evaluated. Protein content of the flour blends (8.84-7.88 %) decreased and fibre content (4.63-6.68 %) increased upon blending of CPP in wheat flour. Wheat flour containing 120 mesh CPP showed better functional properties [water absorption (1.16-1.47 %), oil absorption (1.11-1.39 %), solubility index (41-50 %) and swelling power (1.34-1.39)] than those containing 72 mesh. Water solvent retention capacity and sucrose solvent retention capacity increased while lactic acid solvent retention capacity and sodium carbonate solvent retention capacity decreased with blending of CPP. Water absorption, dough development time and degree of softening increased whereas, dough stability and mixing tolerance decreased with increasing CPP. The highest decrease in pasting was observed flour containing 72 mesh CPP. Rheology of dough containing 120 mesh CPP closely resembled the control. Color of flour and cookies increased with blending of CPP irrespective of mesh size. Antioxidant activity of cookies was higher than the flour blends. The cookies containing CPP of 72 mesh showed the lowest hardness. However, cookies containing CPP of 120 mesh showed the best sensory properties. Incorporation of 120 mesh CPP produced low gluten cookies with manageable flour and dough characteristics and better antioxidant and sensory properties.

Preparation of refractory cermet structures for lithium compatibility testing

NASA Technical Reports Server (NTRS)

Heestand, R. L.; Jones, R. A.; Wright, T. R.; Kizer, D. E.

1973-01-01

High-purity nitride and carbide cermets were synthesized for compatability testing in liquid lithium. A process was developed for the preparation of high-purity hafnium nitride powder, which was subsequently blended with tungsten powder or tantalum nitride and tungsten powders and fabricated into 3 in diameter billets by uniaxial hot pressing. Specimens were then cut from the billets for compatability testing. Similar processing techniques were applied to produce hafnium carbide and zirconium carbide cermets for use in the testing program. All billets produced were characterized with respect to chemistry, structure, density, and strength properties.

Effective Lactobacillus plantarum and Bifidobacterium infantis encapsulation with chia seed (Salvia hispanica L.) and flaxseed (Linum usitatissimum L.) mucilage and soluble protein by spray drying.

PubMed

Bustamante, Mariela; Oomah, B Dave; Rubilar, Mónica; Shene, Carolina

2017-02-01

Mucilage (M) and soluble protein (SP) extracted from chia seed and flaxseed were used as encapsulating material for two probiotic bacteria: Bifidobacterium infantis and Lactobacillus plantarum by spray drying. Probiotic survival and viability after spray drying and during storage were evaluated. B. infantis and L. plantarum displayed high survival (⩾98%) after encapsulation with mixtures of maltodextrin (MD) combined with M and SP from flaxseed (MD:FM:FSP - 7.5:0.2:7.5%, w/w/w) and chia seed (MD:CM:CSP - 7.5:0.6:7.5%, w/w/w), respectively. These ternary blends protected the probiotics and enhanced their resistance to simulated gastric juice and bile solution. Probiotics encapsulated with the ternary blends incorporated in instant juice powder exhibited high viability (>9Log10CFU/g) after 45days refrigerated storage. Encapsulation with the ternary blends reduced particle size of the probiotic powders thereby offering additional functional benefits. Our results reveal that chia seed and flaxseed are excellent sources of probiotic encapsulating agents. Copyright © 2016 Elsevier Ltd. All rights reserved.

Method of preventing oxidation of graphite fireproof material

NASA Technical Reports Server (NTRS)

Yamauchi, S.; Suzuki, H.

1981-01-01

A method of preventing oxidation of graphite fireproof material is given. A blend of 1 to 33 weight parts alumina and 3 to 19 parts of K2O + Na2O in 100 parts of SiO2 is pulverized followed by addition of 5 to 160 parts of silicon carbide powder in 100 parts of the mixture. This is thoroughly blended and coated on the surface of graphite fireproof material.

Laser Powder Cladding of Ti-6Al-4V α/β Alloy

PubMed Central

Al-Sayed Ali, Samar Reda; Hussein, Abdel Hamid Ahmed; Nofal, Adel Abdel Menam Saleh; Elgazzar, Haytham Abdelrafea; Sabour, Hassan Abdel

2017-01-01

Laser cladding process was performed on a commercial Ti-6Al-4V (α + β) titanium alloy by means of tungsten carbide-nickel based alloy powder blend. Nd:YAG laser with a 2.2-KW continuous wave was used with coaxial jet nozzle coupled with a standard powder feeding system. Four-track deposition of a blended powder consisting of 60 wt % tungsten carbide (WC) and 40 wt % NiCrBSi was successfully made on the alloy. The high content of the hard WC particles is intended to enhance the abrasion resistance of the titanium alloy. The goal was to create a uniform distribution of hard WC particles that is crack-free and nonporous to enhance the wear resistance of such alloy. This was achieved by changing the laser cladding parameters to reach the optimum conditions for favorable mechanical properties. The laser cladding samples were subjected to thorough microstructure examinations, microhardness and abrasion tests. Phase identification was obtained by X-ray diffraction (XRD). The obtained results revealed that the best clad layers were achieved at a specific heat input value of 59.5 J·mm−2. An increase by more than three folds in the microhardness values of the clad layers was achieved and the wear resistance was improved by values reaching 400 times. PMID:29036935

Laser Powder Cladding of Ti-6Al-4V α/β Alloy.

PubMed

Al-Sayed Ali, Samar Reda; Hussein, Abdel Hamid Ahmed; Nofal, Adel Abdel Menam Saleh; Hasseb Elnaby, Salah Elden Ibrahim; Elgazzar, Haytham Abdelrafea; Sabour, Hassan Abdel

2017-10-15

Laser cladding process was performed on a commercial Ti-6Al-4V (α + β) titanium alloy by means of tungsten carbide-nickel based alloy powder blend. Nd:YAG laser with a 2.2-KW continuous wave was used with coaxial jet nozzle coupled with a standard powder feeding system. Four-track deposition of a blended powder consisting of 60 wt % tungsten carbide (WC) and 40 wt % NiCrBSi was successfully made on the alloy. The high content of the hard WC particles is intended to enhance the abrasion resistance of the titanium alloy. The goal was to create a uniform distribution of hard WC particles that is crack-free and nonporous to enhance the wear resistance of such alloy. This was achieved by changing the laser cladding parameters to reach the optimum conditions for favorable mechanical properties. The laser cladding samples were subjected to thorough microstructure examinations, microhardness and abrasion tests. Phase identification was obtained by X-ray diffraction (XRD). The obtained results revealed that the best clad layers were achieved at a specific heat input value of 59.5 J·mm -2 . An increase by more than three folds in the microhardness values of the clad layers was achieved and the wear resistance was improved by values reaching 400 times.

Relationships between surface coverage ratio and powder mechanics of binary adhesive mixtures for dry powder inhalers.

PubMed

Rudén, Jonas; Frenning, Göran; Bramer, Tobias; Thalberg, Kyrre; Alderborn, Göran

2018-04-25

The aim of this paper was to study relationships between the content of fine particles and the powder mechanics of binary adhesive mixtures and link these relationships to the blend state. Mixtures with increasing amounts of fine particles (increasing surface coverage ratios (SCR)) were prepared using Lactopress SD as carrier and micro particles of lactose as fines (2.7 µm). Indicators of unsettled bulk density, compressibility and flowability were derived and the blend state was visually examined by imaging. The powder properties studied showed relationships to the SCR characterised by stages. At low SCR, the fine particles predominantly gathered in cavities of the carriers, giving increased bulk density and unchanged or improved flow. Thereafter, increased SCR gave a deposition of particles at the enveloped carrier surface with a gradually more irregular adhesion layer leading to a reduced bulk density and a step-wise reduced flowability. The mechanics of the mixtures at a certain stage were dependent on the structure and the dynamics of the adhesion layer and transitions between the stages were controlled by the evolution of the adhesion layer. It is advisable to use techniques based on different types of flow in order to comprehensively study the mechanics of adhesive mixtures. Copyright © 2018 Elsevier B.V. All rights reserved.

Laser Additive Manufacturing of Magnetic Materials

NASA Astrophysics Data System (ADS)

Mikler, C. V.; Chaudhary, V.; Borkar, T.; Soni, V.; Jaeger, D.; Chen, X.; Contieri, R.; Ramanujan, R. V.; Banerjee, R.

2017-03-01

While laser additive manufacturing is becoming increasingly important in the context of next-generation manufacturing technologies, most current research efforts focus on optimizing process parameters for the processing of mature alloys for structural applications (primarily stainless steels, titanium base, and nickel base alloys) from pre-alloyed powder feedstocks to achieve properties superior to conventionally processed counterparts. However, laser additive manufacturing or processing can also be applied to functional materials. This article focuses on the use of directed energy deposition-based additive manufacturing technologies, such as the laser engineered net shaping (LENS™) process, to deposit magnetic alloys. Three case studies are presented: Fe-30 at.%Ni, permalloys of the type Ni-Fe-V and Ni-Fe-Mo, and Fe-Si-B-Cu-Nb (derived from Finemet) alloys. All these alloys have been processed from a blend of elemental powders used as the feedstock, and their resultant microstructures, phase formation, and magnetic properties are discussed in this paper. Although these alloys were produced from a blend of elemental powders, they exhibited relatively uniform microstructures and comparable magnetic properties to those of their conventionally processed counterparts.

Effect of storage on the chemical composition, microbiological load, and sensory properties of cassava starch-based custard powder

PubMed Central

Awoyale, Wasiu; Sanni, Lateef O; Shittu, Taofik A; Adegunwa, Mojisola O

2015-01-01

The effect of storage on the chemical, microbiological, and sensory properties of cassava starch-based custard powder (CbCP) blends as mixture of yellow-fleshed cassava root starch (YfCRS) (90–98%) and whole egg powder (WEP) (2–10%) was investigated. These were prepared using central composite rotatable design, and separately packaged in polyvinyl chloride plastic can and stored in storage box (30 ± 2°C). The chemical and microbiological analyses of the stored CbCP were evaluated at 3 weeks intervals, while the sensory property was determined at 6 weeks interval for 24 weeks. The result showed that the protein, fat, and the total-β-carotene contents of the CbCP decreased significantly (P ≤ 0.001) after storage while moisture content and microbiological load increased. All the CbCP sensory attributes were accepted at the end of storage, except taste and color. The CbCP gruel prepared from 94% YfCRS: 0.34% WEP and 90% YfCRS: 2% WEP blends were the most acceptable after storage. PMID:26405528

Effect of storage on the chemical composition, microbiological load, and sensory properties of cassava starch-based custard powder.

PubMed

Awoyale, Wasiu; Sanni, Lateef O; Shittu, Taofik A; Adegunwa, Mojisola O

2015-09-01

The effect of storage on the chemical, microbiological, and sensory properties of cassava starch-based custard powder (CbCP) blends as mixture of yellow-fleshed cassava root starch (YfCRS) (90-98%) and whole egg powder (WEP) (2-10%) was investigated. These were prepared using central composite rotatable design, and separately packaged in polyvinyl chloride plastic can and stored in storage box (30 ± 2°C). The chemical and microbiological analyses of the stored CbCP were evaluated at 3 weeks intervals, while the sensory property was determined at 6 weeks interval for 24 weeks. The result showed that the protein, fat, and the total-β-carotene contents of the CbCP decreased significantly (P ≤ 0.001) after storage while moisture content and microbiological load increased. All the CbCP sensory attributes were accepted at the end of storage, except taste and color. The CbCP gruel prepared from 94% YfCRS: 0.34% WEP and 90% YfCRS: 2% WEP blends were the most acceptable after storage.

Quantitative assessment of specific defects in roasted ground coffee via infrared-photoacoustic spectroscopy.

PubMed

Dias, Rafael Carlos Eloy; Valderrama, Patrícia; Março, Paulo Henrique; Dos Santos Scholz, Maria Brigida; Edelmann, Michael; Yeretzian, Chahan

2018-07-30

Chemical analyses and sensory evaluation are the most applied methods for quality control of roasted and ground coffee (RG). However, faster alternatives would be highly valuable. Here, we applied infrared-photoacoustic spectroscopy (FTIR-PAS) on RG powder. Mixtures of specific defective beans were blended with healthy (defect-free) Coffea arabica and Coffea canephora bases in specific ratios, forming different classes of blends. Principal Component Analysis allowed predicting the amount/fraction and nature of the defects in blends while partial Least Squares Discriminant Analysis revealed similarities between blends (=samples). A successful predictive model was obtained using six classes of blends. The model could classify 100% of the samples into four classes. The specificities were higher than 0.9. Application of FTIR-PAS on RG coffee to characterize and classify blends has shown to be an accurate, easy, quick and "green" alternative to current methods. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Effect of gamma irradiation on ethylene propylene diene terpolymer rubber composites

NASA Astrophysics Data System (ADS)

Abou Zeid, M. M.; Rabie, S. T.; Nada, A. A.; Khalil, A. M.; Hilal, R. H.

2008-01-01

Composites of ethylene propylene dine terpolymer rubber (EPDM), high density polyethylene (HDPE) and ground tire rubber powder (GTR) at different ratios were subjected to gamma irradiation at various doses up to 250 kGy. The physical, mechanical and thermal properties were investigated as a function of irradiation dose and blend composition. Gamma irradiation led to a significant improvement in the properties for all blend compositions. The results indicate that the improvement in properties is inversely proportional to the substituted ratio of GTR, attributed to the development of an interfacial adhesion between GTR and blend components. The results were confirmed by examining the fracture surfaces by scanning electron microscopy.

Sampling bias in blending validation and a different approach to homogeneity assessment.

PubMed

Kraemer, J; Svensson, J R; Melgaard, H

1999-02-01

Sampling of batches studied for validation is reported. A thief particularly suited for granules, rather than cohesive powders, was used in the study. It is shown, as has been demonstrated in the past, that traditional 1x to 3x thief sampling of a blend is biased, and that the bias decreases as the sample size increases. It is shown that taking 50 samples of tablets after blending and testing this subpopulation for normality is a discriminating manner of testing for homogeneity. As a criterion, it is better than sampling at mixer or drum stage would be even if an unbiased sampling device were available.

Dispersion strengthened nickel-yttria sheet alloy produced from comminuted powders

NASA Technical Reports Server (NTRS)

Sikora, P. F.; Quatinetz, M.

1973-01-01

An investigation was conducted to determine whether a nickel matrix with yttria as a dispersoid could be produced by a comminution and blending (wet attrition-NASCAB) approach. Concentration of yttria, powder cleaning temperature, screening (sieving) of the powders, and amount of thermomechanical working were major variables. Tensile strength and stress-rupture life at 1093 C were determined. A product containing 4v/o Y2O3, cleaned at 315 or 371 C with screening exhibited 1093 C tensile strength equivalent to NASCAB Ni-4ThO2 and to commercially produced thoriated nickel sheet.

Effects of mild processing pressures on the performance of dry powder inhaler formulations for inhalation therapy. 1: Budesonide and lactose.

PubMed

Marek, Steve R; Donovan, Martin J; Smyth, Hugh D C

2011-05-01

Batch-to-batch variability, whereby distinct batches of dry powder inhaler formulations, though manufactured with identical components and specifications, may exhibit significant variations in aerosol performance, is a major obstacle to consistent and reproducible drug delivery for inhalation therapy. This variability may arise from processing or manufacturing effects that have yet to be investigated. This study focused on the potential effects of mild compression forces experienced during powder manufacture and transport (such as during the filling of, or storage in, a hopper) on the flowability and aerosol performance of a lactose-based dry powder inhaler formulation. Different grades of inhalation lactose were subjected to typical compression forces by either placing a weight of known mass on the sample or by using a Texture Analyzer to apply a constant force while measuring the distance of compaction. Powder flowability was evaluated with a rotating drum apparatus by imaging the avalanching of the powder over time. The average avalanche angle and avalanche time were used to determine the flowability of each sample, both before and after compression treatment. Aerosol performance of treated and untreated lactose/budesonide blends (2% (w/w)) was assessed in dispersion studies using a next generation impactor. At compression forces in excess of 5 kPa, the flowability of milled lactose was decreased relative to the untreated sample. Compression of lactose prior to blending caused a decrease in in vitro aerosol dispersion performance. However, dispersion performance was unchanged when compression occurred subsequent to drug blending. In contrast, inhalation grade sieved lactose, differing from the milled grade with a lower concentration of lactose fines (<10 μm) and larger overall particle sizes, exhibited no statistical differences in either flowability or dispersion performance across all experimental treatments. Thus, the compression of the lactose fines onto the surfaces of the larger lactose particles due to mild processing pressures is hypothesized to be the cause of these observed performance variations. It was shown that simulations of storage and transport in an industrial scale hopper can induce significant variations in formulation performance, and it is speculated that this could be a source of batch-to-batch variations. Copyright © 2011 Elsevier B.V. All rights reserved.

High temperature dispersion strengthening of NiAl

NASA Technical Reports Server (NTRS)

Sherman, M.; Vedula, K.

1986-01-01

A potential high temperature strengthening mechanism for alloys based on the intermetallic compound NiAl was investigated. This study forms part of an overall program at NASA Lewis Research Center for exploring the potential of alloys based on NiAl for high temperature applications. An alloy containing 2.26 at% Nb and produced by hot extrusion of blended powders was examined in detail using optical and electron microscopy. Interdiffusion between the blended Nb and NiAl powders results in the formation of intermediate phases. A fine dispersion of precipitates of a hexagonal, ordered NiAlNb phases in a matrix of NiAl can be produced and this results in strengthening of the alloy by interfering with dislocation motion at high temperature. These precipitates are, however, found to coarsen during the high temperature (1300 K) deformation at slow strain rates and this may impose some limitatioins on the use of this strengthening mechanism.

Thermogravimetric characteristics of typical municipal solid waste fractions during co-pyrolysis.

PubMed

Zhou, Hui; Long, YanQiu; Meng, AiHong; Li, QingHai; Zhang, YanGuo

2015-04-01

The interactions of nine typical municipal solid waste (MSW) fractions during pyrolysis were investigated using the thermogravimetric analyzer (TGA). To compare the mixture results with the calculation results of superposition of single fractions quantitatively, TG overlap ratio was introduced. There were strong interactions between orange peel and rice (overlap ratio 0.9736), and rice and poplar wood (overlap ratio 0.9774). The interactions of mixture experiments postponed the peak and lowered the peak value. Intense interactions between PVC and rice, poplar wood, tissue paper, wool, terylene, and rubber powder during co-pyrolysis were observed, and the pyrolysis at low temperature was usually promoted. The residue yield was increased when PVC was blended with rice, poplar wood, tissue paper, or rubber powder; while the residue yield was decreased when PVC was blended with wool. Copyright © 2014 Elsevier Ltd. All rights reserved.

Microstructure Evolution and Rapid Solidification Behavior of Blended Nickel-Based Superalloy Powders Fabricated by Laser Powder Deposition

NASA Astrophysics Data System (ADS)

Tian, Y.; Gauvin, R.; Brochu, M.

2016-07-01

Laser powder deposition was performed on a substrate of Inconel 738 using blended powders of Mar M247 and Amdry DF3 with a ratio of 4:1 for repairing purposes. In the as-deposited condition, continuous secondary phases composed of γ-Ni3B eutectics and discrete (Cr, W)B borides were observed in inter-dendritic regions, and time-dependent nucleation simulation results confirmed that (Cr, W)B was the primary secondary phase formed during rapid solidification. Supersaturated solid solution of B was detected in the γ solid solution dendritic cores. The Kurz-Giovanola-Trivedi model was performed to predict the interfacial morphology and correlate the solidification front velocity (SFV) with dendrite tip radius. It was observed from high-resolution scanning electron microscopy that the dendrite tip radius of the upper region was in the range of 15 to 30 nm, which yielded a SFV of approx 30 cm/s. The continuous growth model for solute trapping behavior developed by Aziz and Kaplan was used to determine that the effective partition coefficient of B was approximately 0.025. Finally, the feasibility of the modeling results were rationalized with the Clyne-Kurz segregation simulation of B, where Clyne-Kurz prediction using a partition coefficient of 0.025 was in good agreement with the electron probe microanalysis results.

Predicting the tensile strength of compacted multi-component mixtures of pharmaceutical powders.

PubMed

Wu, Chuan-Yu; Best, Serena M; Bentham, A Craig; Hancock, Bruno C; Bonfield, William

2006-08-01

Pharmaceutical tablets are generally produced by compacting a mixture of several ingredients, including active drugs and excipients. It is of practical importance if the properties of such tablets can be predicted on the basis of the ones for constituent components. The purpose of this work is to develop a theoretical model which can predict the tensile strength of compacted multi-component pharmaceutical mixtures. The model was derived on the basis of the Ryshkewitch-Duckworth equation that was originally proposed for porous materials. The required input parameters for the model are the relative density or solid fraction (ratio of the volume of solid materials to the total volume of the tablets) of the multi-component tablets and parameters associated with the constituent single-component powders, which are readily accessible. The tensile strength of tablets made of various powder blends at different relative density was also measured using diametrical compression. It has been shown that the tensile strength of the multi-component powder compacts is primarily a function of the solid fraction. Excellent agreement between prediction and experimental data for tablets of binary, ternary and four-component blends of some widely used pharmaceutical excipients was obtained. It has been demonstrated that the proposed model can well predict the tensile strength of multi-component pharmaceutical tablets. Thus, the model will be a useful design tool for formulation engineers in the pharmaceutical industry.

Impact of Various Compression Ratio on the Compression Ignition Engine with Diesel and Jatropha Biodiesel

NASA Astrophysics Data System (ADS)

Sivaganesan, S.; Chandrasekaran, M.; Ruban, M.

2017-03-01

The present experimental investigation evaluates the effects of using blends of diesel fuel with 20% concentration of Methyl Ester of Jatropha biodiesel blended with various compression ratio. Both the diesel and biodiesel fuel blend was injected at 23º BTDC to the combustion chamber. The experiment was carried out with three different compression ratio. Biodiesel was extracted from Jatropha oil, 20% (B20) concentration is found to be best blend ratio from the earlier experimental study. The engine was maintained at various compression ratio i.e., 17.5, 16.5 and 15.5 respectively. The main objective is to obtain minimum specific fuel consumption, better efficiency and lesser Emission with different compression ratio. The results concluded that full load show an increase in efficiency when compared with diesel, highest efficiency is obtained with B20MEOJBA with compression ratio 17.5. It is noted that there is an increase in thermal efficiency as the blend ratio increases. Biodiesel blend has performance closer to diesel, but emission is reduced in all blends of B20MEOJBA compared to diesel. Thus this work focuses on the best compression ratio and suitability of biodiesel blends in diesel engine as an alternate fuel.

Hardgrove grindability study of Powder River Basin and Appalachian coal components in the blend to a midwestern power station

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

Padgett, P.L.; Hower, J.C.

1996-12-31

Five coals representing four distinct coal sources blended at a midwestern power station were subjected to detailed analysis of their Hardgrove grindability. The coals are: a low-sulfur, high volatile A bituminous Upper Elkhorn No. 3 coal (Pike County, KY); a medium-sulfur, high volatile A bituminous Pittsburgh coal (southwestern PA); a low-sulfur, subbituminous Wyodak coal from two mines in the eastern Powder River Basin (Campbell County, WY). The feed and all samples processed in the Hardgrove grindability test procedure were analyzed for their maceral and microlithotype content. The high-vitrinite Pittsburgh coal and the relatively more petrographically complex Upper Elkhorn No. 3more » coal exhibit differing behavior in grindability. The Pittsburgh raw feed, 16x30 mesh fraction (HGI test fraction), and the {minus}30 mesh fraction (HGI reject) are relatively similar petrographically, suggesting that the HGI test fraction is reasonably representative of the whole feed. The eastern Kentucky coal is not as representative of the whole feed, the HGI test fraction having lower vitrinite than the rejected {minus}30 mesh fraction. The Powder River Basin coals are high vitrinite and show behavior similar to the Pittsburgh coal.« less

Weldability Characteristics of Sintered Hot-Forged AISI 4135 Steel Produced through P/M Route by Using Pulsed Current Gas Tungsten Arc Welding

NASA Astrophysics Data System (ADS)

Joseph, Joby; Muthukumaran, S.; Pandey, K. S.

2016-01-01

Present investigation is an attempt to study the weldability characteristics of sintered hot-forged plates of AISI 4135 steel produced through powder metallurgy (P/M) route using matching filler materials of ER80S B2. Compacts of homogeneously blended elemental powders corresponding to the above steel were prepared on a universal testing machine (UTM) by taking pre-weighed powder blend with a suitable die, punch and bottom insert assembly. Indigenously developed ceramic coating was applied on the entire surface of the compacts in order to protect them from oxidation during sintering. Sintered preforms were hot forged to flat, approximately rectangular plates, welded by pulsed current gas tungsten arc welding (PCGTAW) processes with aforementioned filler materials. Microstructural, tensile and hardness evaluations revealed that PCGTAW process with low heat input could produce weldments of good quality with almost nil defects. It was established that PCGTAW joints possess improved tensile properties compared to the base metal and it was mainly attributed to lower heat input, resulting in finer fusion zone grains and higher fusion zone hardness. Thus, the present investigation opens a new and demanding field in research.

Nuclear Rocket Ceramic Metal Fuel Fabrication Using Tungsten Powder Coating and Spark Plasma Sintering

NASA Technical Reports Server (NTRS)

Barnes, M. W.; Tucker, D. S.; Hone, L.; Cook, S.

2017-01-01

Nuclear thermal propulsion is an enabling technology for crewed Mars missions. An investigation was conducted to evaluate spark plasma sintering (SPS) as a method to produce tungsten-depleted uranium dioxide (W-dUO2) fuel material when employing fuel particles that were tungsten powder coated. Ceramic metal fuel wafers were produced from a blend of W-60vol% dUO2 powder that was sintered via SPS. The maximum sintering temperatures were varied from 1,600 to 1,850 C while applying a 50-MPa axial load. Wafers exhibited high density (>95% of theoretical) and a uniform microstructure (fuel particles uniformly dispersed throughout tungsten matrix).

Process analytical technology in continuous manufacturing of a commercial pharmaceutical product.

PubMed

Vargas, Jenny M; Nielsen, Sarah; Cárdenas, Vanessa; Gonzalez, Anthony; Aymat, Efrain Y; Almodovar, Elvin; Classe, Gustavo; Colón, Yleana; Sanchez, Eric; Romañach, Rodolfo J

2018-03-01

The implementation of process analytical technology and continuous manufacturing at an FDA approved commercial manufacturing site is described. In this direct compaction process the blends produced were monitored with a Near Infrared (NIR) spectroscopic calibration model developed with partial least squares (PLS) regression. The authors understand that this is the first study where the continuous manufacturing (CM) equipment was used as a gravimetric reference method for the calibration model. A principal component analysis (PCA) model was also developed to identify the powder blend, and determine whether it was similar to the calibration blends. An air diagnostic test was developed to assure that powder was present within the interface when the NIR spectra were obtained. The air diagnostic test as well the PCA and PLS calibration model were integrated into an industrial software platform that collects the real time NIR spectra and applies the calibration models. The PCA test successfully detected an equipment malfunction. Variographic analysis was also performed to estimate the sampling analytical errors that affect the results from the NIR spectroscopic method during commercial production. The system was used to monitor and control a 28 h continuous manufacturing run, where the average drug concentration determined by the NIR method was 101.17% of label claim with a standard deviation of 2.17%, based on 12,633 spectra collected. The average drug concentration for the tablets produced from these blends was 100.86% of label claim with a standard deviation of 0.4%, for 500 tablets analyzed by Fourier Transform Near Infrared (FT-NIR) transmission spectroscopy. The excellent agreement between the mean drug concentration values in the blends and tablets produced provides further evidence of the suitability of the validation strategy that was followed. Copyright © 2018 Elsevier B.V. All rights reserved.

An investigation into the impact of magnesium stearate on powder feeding during roller compaction.

PubMed

Dawes, Jason; Gamble, John F; Greenwood, Richard; Robbins, Phil; Tobyn, Mike

2012-01-01

A systematic evaluation on the effect of magnesium stearate on the transmission of a placebo formulation from the hopper to the rolls during screw fed roller compaction has been carried out. It is demonstrated that, for a system with two 'knurled' rollers, addition of 0.5% w/w magnesium stearate can lead to a significant increase in ribbon mass throughput, with a consequential increase in roll gap, compared to an unlubricated formulation (manufactured at equivalent process conditions). However, this effect is reduced if one of the rollers is smooth. Roller compaction of a lubricated formulation using two smooth rollers was found to be ineffective due to a reduction in friction at the powder/roll interface, i.e. powder was not drawn through the rollers leading to a blockage in the feeding system. An increase in ribbon mass throughput could also be achieved if the equipment surfaces were pre-lubricated. However this increase was found to be temporary suggesting that the residual magnesium stearate layer was removed from the equipment surfaces. Powder sticking to the equipment surfaces, which is common during pharmaceutical manufacturing, was prevented if magnesium stearate was present either in the blend, or at the roll surface. It is further demonstrated that the influence of the hopper stirrer, which is primarily used to prevent bridge formation in the hopper and help draw powder more evenly into the auger chamber, can lead to further mixing of the formulation, and could therefore affect a change in the lubricity of the carefully blended input material.

Titanium Carbide Bipolar Plate for Electrochemical Devices

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

LaConti, Anthony B.; Griffith, Arthur E.; Cropley, Cecelia C.

Titanium carbide comprises a corrosion resistant, electrically conductive, non-porous bipolar plate for use in an electrochemical device. The process involves blending titanium carbide powder with a suitable binder material, and molding the mixture, at an elevated temperature and pressure.

Raman spectroscopy as a PAT for pharmaceutical blending: Advantages and disadvantages.

PubMed

Riolo, Daniela; Piazza, Alessandro; Cottini, Ciro; Serafini, Margherita; Lutero, Emilio; Cuoghi, Erika; Gasparini, Lorena; Botturi, Debora; Marino, Iari Gabriel; Aliatis, Irene; Bersani, Danilo; Lottici, Pier Paolo

2018-02-05

Raman spectroscopy has been positively evaluated as a tool for the in-line and real-time monitoring of powder blending processes and it has been proved to be effective in the determination of the endpoint of the mixing, showing its potential role as process analytical technology (PAT). The aim of this study is to show advantages and disadvantages of Raman spectroscopy with respect to the most traditional HPLC analysis. The spectroscopic results, obtained directly on raw powders, sampled from a two-axis blender in real case conditions, were compared with the chromatographic data obtained on the same samples. The formulation blend used for the experiment consists of active pharmaceutical ingredient (API, concentrations 6.0% and 0.5%), lactose and magnesium stearate (as excipients). The first step of the monitoring process was selecting the appropriate wavenumber region where the Raman signal of API is maximal and interference from the spectral features of excipients is minimal. Blend profiles were created by plotting the area ratios of the Raman peak of API (A API ) at 1598cm -1 and the Raman bands of excipients (A EXC ), in the spectral range between 1560 and 1630cm -1 , as a function of mixing time: the API content can be considered homogeneous when the time-dependent dispersion of the area ratio is minimized. In order to achieve a representative sampling with Raman spectroscopy, each sample was mapped in a motorized XY stage by a defocused laser beam of a micro-Raman apparatus. Good correlation between the two techniques has been found only for the composition at 6.0% (w/w). However, standard deviation analysis, applied to both HPLC and Raman data, showed that Raman results are more substantial than HPLC ones, since Raman spectroscopy enables generating data rich blend profiles. In addition, the relative standard deviation calculated from a single map (30 points) turned out to be representative of the degree of homogeneity for that blend time. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of Particle Morphology on Cold Spray Deposition of Chromium Carbide-Nickel Chromium Cermet Powders

NASA Astrophysics Data System (ADS)

Fernandez, Ruben; Jodoin, Bertrand

2017-08-01

Nickel chromium-chromium carbide coatings provide good corrosion and wear resistance at high temperatures, making them ideal for applications where a harsh environment and high temperatures are expected. Thermal spray processes are preferred as deposition technique of cermets, but the high process temperatures can lead to decarburization and reduction of the coatings properties. Cold spray uses lower temperatures preventing decarburization. Since the metallic phase remains solid, the feedstock powder morphology becomes crucial on the deposition behavior. Six commercially available powders were studied, varying in morphology and metal/ceramic ratios. The powders were categorized into 4 groups depending on their morphology. Spherical powders lead to substrate erosion due to their limited overall ductility. Porous agglomerated and sintered powders lead to severely cracked coatings. For dense agglomerated and sintered powders, the outcome depended on the initial metal/ceramic ratio: powders with 25 wt.% NiCr led to substrate erosion while 35 wt.% NiCr powders led to dense coatings. Finally, blended ceramic-metal mixtures also lead to dense coatings. All coatings obtained had lower ceramic content than the initial feedstock powders. Interrupted spray tests, combined with FEA, helped drawing conclusions on the deposition behavior to explain the obtained results.

Optimizing adsorption of blue pigment from wastewater by nano-porous modified Na-bentonite using spectrophotometry based on response surface method

NASA Astrophysics Data System (ADS)

Moradi, Neshat; Salem, Shiva; Salem, Amin

2018-03-01

This work highlighted the effective activation of bentonite paste to produce nano-porous powder for removal of cationic dye from wastewater. The effects of activation parameters such as soda and moisture contents, ageing time and temperature were analyzed using response surface methodology (RSM). The significance of independent variables and their interactions were tested by blending the obtained powders with wastewater and then the adsorption was evaluated, spectrophotometrically. The experiments were carried out by preparation of pastes according to response surface methodology and central composite design, which is the standard method, was used to evaluate the effects and interactions of four factors on the treatment efficiency. RSM was demonstrated as an appropriate approach for optimization of alkali activation. The optimal conditions obtained from the desirable responses were 5.0 wt% soda and 45.0 wt% moisture, respectively in which the powder activation was carried out at 150 °C. In order to well understand the role of nano-structured material on dye removal, the adsorbents were characterized through X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and Brunauer-Emmett-Teller surface area measurement. Finally, the analysis clearly demonstrates that the dye removal onto prepared adsorbent is well fitted with Langmuir isotherm compared to the other isotherm models. The low cost of material and facile process support the further development for commercial application purpose.

Limitations of high dose carrier based formulations.

PubMed

Yeung, Stewart; Traini, Daniela; Tweedie, Alan; Lewis, David; Church, Tanya; Young, Paul M

2018-06-10

This study was performed to investigate how increasing the active pharmaceutical ingredient (API) content within a formulation affects the dispersion of particles and the aerosol performance efficiency of a carrier based dry powder inhalable (DPI) formulation, using a custom dry powder inhaler (DPI) development rig. Five formulations with varying concentrations of API beclomethasone dipropionate (BDP) between 1% and 30% (w/w) were formulated as a multi-component carrier system containing coarse lactose and fine lactose with magnesium stearate. The morphology of the formulation and each component were investigated using scanning electron micrographs while the particle size was measured by laser diffraction. The aerosol performance, in terms of aerodynamic diameter, was assessed using the British pharmacopeia Apparatus E cascade impactor (Next generation impactor). Chemical analysis of the API was observed by high performance liquid chromatography (HPLC). Increasing the concentration of BDP in the blend resulted in increasing numbers and size of individual agglomerates and densely packed BDP multi-layers on the surface of the lactose carrier. BDP present within the multi-layer did not disperse as individual primary particles but as dense agglomerates, which led to a decrease in aerosol performance and increased percentage of BDP deposition within the Apparatus E induction port and pre-separator. As the BDP concentration in the blends increases, aerosol performance of the formulation decreases, in an inversely proportional manner. Concurrently, the percentage of API deposition in the induction port and pre-separator could also be linked to the amount of micronized particles (BDP and Micronized composite carrier) present in the formulation. The effect of such dose increase on the behaviour of aerosol dispersion was investigated to gain greater insight in the development and optimisation of higher dosed carrier-based formulations. Copyright © 2018 Elsevier B.V. All rights reserved.

Titanium carbide bipolar plate for electrochemical devices

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

LaConti, Anthony B.; Griffith, Arthur E.; Cropley, Cecelia C.

A corrosion resistant, electrically conductive, non-porous bipolar plate is made from titanium carbide for use in an eletrochemical device. The process involves blending titanium carbide powder with a suitable binder material, and molding the mixture, at an elevated temperature and pressure.

Effects of Humidity On the Flow Characteristics of PS304 Plasma Spray Feedstock Powder Blend

NASA Technical Reports Server (NTRS)

Stanford, Malcolm K.; DellaCorte, Christopher

2002-01-01

The effects of environmental humidity on the flow characteristics of PS304 feedstock have been investigated. Angular and spherical BaF2-CaF2 powder was fabricated by comminution and by atomization, respectively. The fluorides were added incrementally to the nichrome, chromia, and silver powders to produce PS304 feedstock. The powders were dried in a vacuum oven and cooled to a Tom temperature under dry nitrogen. The flow of the powder was studied from 2 to 100 percent relative humidity (RH) The results suggest that the feedstock flow is slightly degraded with increasing humidity below 66 percent RH and is more affected above 66 percent RH. There was no flow above 88 percent RH. Narrower particle size distributions of the angular fluorides allowed flow up to 95 percent RH. These results offer guidance that enhances the commercial potential for this material system.

METHOD OF PREPARING A CERAMIC FUEL ELEMENT

DOEpatents

Ross, W.T.; Bloomster, C.H.; Bardsley, R.E.

1963-09-01

A method is described for preparing a fuel element from -325 mesh PuO/ sub 2/ and -20 mesh UO/sub 2/, and the steps of screening --325 mesh UO/sub 2/ from the -20 mesh UO/sub 2/, mixing PuO/sub 2/ with the --325 mesh UO/sub 2/, blending this mixture with sufficient --20 mesh UO/sub 2/ to obtain the desired composition, introducing the blend into a metal tube, repeating the procedure until the tube is full, and vibrating the tube to compact the powder are included. (AEC)

Grinding as an approach to the production of high-strength, dispersion-strengthened nickel-base alloys

NASA Technical Reports Server (NTRS)

Orth, N. W.; Quatinetz, M.; Weeton, J. W.

1970-01-01

Mechanical process produces dispersion-strengthened metal alloys. Power surface contamination during milling is removed by a cleaning method that involves heating thin shapes or partially-compacted milled powder blends in hydrogen to carefully controlled temperature schedules.

Iron-phosphate ceramics for solidification of mixed low-level waste

DOEpatents

Aloy, Albert S.; Kovarskaya, Elena N.; Koltsova, Tatiana I.; Macheret, Yevgeny; Medvedev, Pavel G.; Todd, Terry

2000-01-01

A method of immobilizing mixed low-level waste is provided which uses low cost materials and has a relatively long hardening period. The method includes: forming a mixture of iron oxide powders having ratios, in mass %, of FeO:Fe.sub.2 O.sub.3 :Fe.sub.3 O.sub.4 equal to 25-40:40-10:35-50, or weighing a definite amount of magnetite powder. Metallurgical cinder can also be used as the source of iron oxides. A solution of the orthophosphoric acid, or a solution of the orthophosphoric acid and ferric oxide, is formed and a powder phase of low-level waste and the mixture of iron oxide powders or cinder (or magnetite powder) is also formed. The acid solution is mixed with the powder phase to form a slurry with the ratio of components (mass %) of waste:iron oxide powders or magnetite:acid solution=30-60:15-10:55-30. The slurry is blended to form a homogeneous mixture which is cured at room temperature to form the final product.

In-line Raman spectroscopic monitoring and feedback control of a continuous twin-screw pharmaceutical powder blending and tableting process.

PubMed

Nagy, Brigitta; Farkas, Attila; Gyürkés, Martin; Komaromy-Hiller, Szofia; Démuth, Balázs; Szabó, Bence; Nusser, Dávid; Borbás, Enikő; Marosi, György; Nagy, Zsombor Kristóf

2017-09-15

The integration of Process Analytical Technology (PAT) initiative into the continuous production of pharmaceuticals is indispensable for reliable production. The present paper reports the implementation of in-line Raman spectroscopy in a continuous blending and tableting process of a three-component model pharmaceutical system, containing caffeine as model active pharmaceutical ingredient (API), glucose as model excipient and magnesium stearate as lubricant. The real-time analysis of API content, blend homogeneity, and tablet content uniformity was performed using a Partial Least Squares (PLS) quantitative method. The in-line Raman spectroscopic monitoring showed that the continuous blender was capable of producing blends with high homogeneity, and technological malfunctions can be detected by the proposed PAT method. The Raman spectroscopy-based feedback control of the API feeder was also established, creating a 'Process Analytically Controlled Technology' (PACT), which guarantees the required API content in the produced blend. This is, to the best of the authors' knowledge, the first ever application of Raman-spectroscopy in continuous blending and the first Raman-based feedback control in the formulation technology of solid pharmaceuticals. Copyright © 2017 Elsevier B.V. All rights reserved.

Sorption of radionuclides by cement-based barrier materials

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

Li, Kefei, E-mail: likefei@tsinghua.edu.cn; Pang, Xiaoyun

2014-11-15

This paper investigates the sorption of radionuclide ions, {sup 137}Cs{sup +} and {sup 90}Sr{sup 2+}, by cement-based barrier materials for radioactive waste disposal. A mortar with ternary binder is prepared and powder samples are ground from the hardened material following a predetermined granulometry. After pre-equilibrium with an artificial pore solution, the sorption behaviors of powder samples are investigated through single sorption and blended sorption. The results show that: (1) no systematic difference is observed for single and blended sorptions thus the interaction between {sup 137}Cs{sup +} and {sup 90}Sr{sup 2+} sorptions must be weak; (2) the sorption kinetics is rapidmore » and all characteristic times are less than 1d; (3) the sorption capacity is enhanced by C–A–S–H hydrates and the measured K{sub d} values can be predicted from C–S–H sorption data with Ca/Si ratio equal to Ca/(Si + Al) ratio.« less

Composition optimization of self-lubricating chromium carbide-based composite coatings for use to 760 deg C

NASA Technical Reports Server (NTRS)

Dellacorte, C.; Sliney, H. E.

1986-01-01

This paper describes new compositions of self-lubricating coatings that contain chromium carbide. A bonded chromium carbide was used as the base stock because of the known excellent wear resistance and the chemical stability of chromium carbide. Additives were silver and barium fluoride/calcium fluoride eutectic. The coating constituents were treated as a ternary system consisting of: (1) the bonded carbide base material, (2) silver, and (3) the eutectic. A study to determine the optimum amounts of each constituent was performed. The various compositions were prepared by powder blending. The blended powders were then plasma sprayed onto superalloy substrates and diamond ground to the desired coating thickness. Friction and wear studies were performed at temperatures from 25 to 760 C in helium and hydrogen. A variety of counterface materials were evaluated with the objective of discovering a satisfactory metal/coating sliding combination for potential applications such as piston ring/cylinder liner couples for Stirling engines.

Composition optimization of self-lubricating chromium-carbide-based composite coatings for use to 760 C

NASA Technical Reports Server (NTRS)

Dellacorte, Chris; Sliney, Harold E.

1987-01-01

This paper describes new compositions of self-lubricating coatings that contain chromium carbide. A bonded chromium carbide was used as the base stock because of the known excellent wear resistance and the chemical stability of chromium carbide. Additives were silver and barium fluoride/calcium fluoride eutectic. The coating constituents were treated as a ternary system consisting of: (1) the bonded carbide base material, (2) silver, and (3) the eutectic. A study to determine the optimum amounts of each constituent was performed. The various compositions were prepared by powder blending. The blended powders were then plasma sprayed onto superalloy substrates and diamond ground to the desired coating thickness. Friction and wear studies were performed at temperatures from 25 to 760 C in helium and hydrogen. A variety of counterface materials were evaluated with the objective of discovering a satisfactory metal/coating sliding combination for potential applications such as piston ring/cylinder liner couples for Stirling engines.

Spark Plasma Co-Sintering of Mechanically Milled Tool Steel and High Speed Steel Powders

PubMed Central

Pellizzari, Massimo; Fedrizzi, Anna; Zadra, Mario

2016-01-01

Hot work tool steel (AISI H13) and high speed steel (AISI M3:2) powders were successfully co-sintered to produce hybrid tool steels that have properties and microstructures that can be modulated for specific applications. To promote co-sintering, which is made difficult by the various densification kinetics of the two steels, the particle sizes and structures were refined by mechanical milling (MM). Near full density samples (>99.5%) showing very fine and homogeneous microstructure were obtained using spark plasma sintering (SPS). The density of the blends (20, 40, 60, 80 wt % H13) was in agreement with the linear rule of mixtures. Their hardness showed a positive deviation, which could be ascribed to the strengthening effect of the secondary particles altering the stress distribution during indentation. A toughening of the M3:2-rich blends could be explained in view of the crack deviation and crack arrest exerted by the H13 particles. PMID:28773603

Spark Plasma Co-Sintering of Mechanically Milled Tool Steel and High Speed Steel Powders.

PubMed

Pellizzari, Massimo; Fedrizzi, Anna; Zadra, Mario

2016-06-16

Hot work tool steel (AISI H13) and high speed steel (AISI M3:2) powders were successfully co-sintered to produce hybrid tool steels that have properties and microstructures that can be modulated for specific applications. To promote co-sintering, which is made difficult by the various densification kinetics of the two steels, the particle sizes and structures were refined by mechanical milling (MM). Near full density samples (>99.5%) showing very fine and homogeneous microstructure were obtained using spark plasma sintering (SPS). The density of the blends (20, 40, 60, 80 wt % H13) was in agreement with the linear rule of mixtures. Their hardness showed a positive deviation, which could be ascribed to the strengthening effect of the secondary particles altering the stress distribution during indentation. A toughening of the M3:2-rich blends could be explained in view of the crack deviation and crack arrest exerted by the H13 particles.

Process for producing silicon nitride based articles of high fracture toughness and strength

DOEpatents

Huckabee, Marvin; Buljan, Sergej-Tomislav; Neil, Jeffrey T.

1991-01-01

A process for producing a silicon nitride-based article of improved fracture toughness and strength. The process involves densifying to at least 98% of theoretical density a mixture including (a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon nitride powder of an average particle size of about 0.2 .mu.m and a surface area of about 8-12 m.sup.2 /g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 .mu.m and a surface area of about 2-4 m.sup.2 /g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified article an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. Optionally, the mixture may be blended with a binder and injection molded to form a green body, which then may be densified by, for example, hot isostatic pressing.

Process for producing silicon nitride based articles of high fracture toughness and strength

DOEpatents

Huckabee, M.; Buljan, S.T.; Neil, J.T.

1991-09-10

A process for producing a silicon nitride-based article of improved fracture toughness and strength is disclosed. The process involves densifying to at least 98% of theoretical density a mixture including (a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon nitride powder of an average particle size of about 0.2 [mu]m and a surface area of about 8-12 m[sup 2]/g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 [mu]m and a surface area of about 2-4 m[sup 2]/g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified article an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. Optionally, the mixture may be blended with a binder and injection molded to form a green body, which then may be densified by, for example, hot isostatic pressing.

Investigation of Tin(II)2,3-naphtalocyanine molecule used as near-infrared sensitive layer in organic up-conversion devices

NASA Astrophysics Data System (ADS)

Melquíades, Mônica C.; Aderne, Rian; Cuin, Alexandre; Quirino, Welber G.; Cremona, Marco; Legnani, Cristiano

2017-07-01

In this work, a near infrared (NIR) sensitive molecule, Tin(II)2,3-naphthalocyanine (SnNc) was characterized by different techniques. UV-Vis spectroscopy and cyclic voltammetry were performed in order to determine the absorption spectrum, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies of this molecule deposited in form of thin films. We found energies of 5.0 ± 0.1 eV and 3.7 ± 0.1 eV for HOMO and LUMO, respectively. The charge carrier mobility was also investigated by space charge limit current technique showing values of μh (8.8 ± 0.1) x 10-5 cm2V-1s-1. SnNc alone or blended with fullerene was used as efficient NIR sensitive layer due to its absorption around 875 nm. The crystalline structure of SnNc was studied by X-ray powder diffraction, showing a monoclinic system and P21/c space group, with cell parameters a = (15.948 ± 6) Å, b = (15.818 ± 2) Å, c = (14.649 ± 1) Å and β = (67.096 ± 6) Å. Desorption/Ionization-Time of Flight Mass Spectrometry (LDI-TOFMS) technique was employed to obtain information of molecular structure of the SnNc in thin film, showing that the thin film of the SnNc has no dimer formation. Due to its absorption around 875 nm, SnNc blended with fullerene was used as efficient NIR sensitive layer in the fabrication of an organic up-conversion device. When the device is submitted to IR radiation, a gain of about 133% was observed in the luminous efficiency when compared to values without IR irradiation.

Energetic powder

DOEpatents

Jorgensen, Betty S.; Danen, Wayne C.

2003-12-23

Fluoroalkylsilane-coated metal particles. The particles have a central metal core, a buffer layer surrounding the core, and a fluoroalkylsilane layer attached to the buffer layer. The particles may be prepared by combining a chemically reactive fluoroalkylsilane compound with an oxide coated metal particle having a hydroxylated surface. The resulting fluoroalkylsilane layer that coats the particles provides them with excellent resistance to aging. The particles can be blended with oxidant particles to form energetic powder that releases chemical energy when the buffer layer is physically disrupted so that the reductant metal core can react with the oxidant.

Method of fabricating thin-walled articles of tungsten-nickel-iron alloy

DOEpatents

Hovis, Jr., Victor M.; Northcutt, Jr., Walter G.

1982-01-01

The present invention relates to a method for fabricating thin-walled high-density structures oftungsten-nickel-iron alloys. A powdered blend of the selected alloy constituents is plasma sprayed onto a mandrel having the desired article configuration. The sprayed deposit is removed from the mandrel and subjected to liquid phase sintering to provide the alloyed structure. The formation of the thin-walled structure by plasma spraying significantly reduces shrinkage, and cracking while increasing physical properties of the structure over that obtainable by employing previously known powder metallurgical procedures.

Method of fabricating thin-walled articles of tungsten-nickel-iron alloy

DOEpatents

Hovis, V.M. Jr.; Northcutt, W.G. Jr.

The present invention relates to a method for fabricating thin-walled high-density structures of tungsten-nickel-iron alloys. A powdered blend of the selected alloy constituents is plasma sprayed onto a mandrel having the desired article configuration. The sprayed deposit is removed from the mandrel and subjected to liquid phase sintering to provide the alloyed structure. The formation of the thin-walled structure by plasma spraying significantly reduces shrinkage, and cracking while increasing physical properties of the structure over that obtainable by employing previously known powder metallurgical procedures.

Preferred delivery method and acceptability of Wheat-Soy Blend (WSB++) as a daily complementary food supplement in northwest Bangladesh.

PubMed

Shamim, Abu Ahmed; Hanif, Abu A M; Merrill, Rebecca D; Campbell, Rebecca K; Kumkum, Mehnaz Alam; Shaikh, Saijuddin; de Pee, Saskia; Ahmed, Tahmeed; Parveen, Monira; Mehra, Sucheta; Klemm, Rolf D W; Labrique, Alain B; West, Keith P; Christian, Parul

2015-01-01

Fortified blended foods (FBFs) are widely used to prevent undernutrition in early childhood in food-insecure settings. We field tested enhanced Wheat Soy Blend (WSB++)-a FBF fortified with micronutrients, milk powder, sugar, and oil-in preparation for a complementary food supplement (CFS) trial in rural northwestern Bangladesh. Formative work was conducted to determine the optimal delivery method (cooked vs. not) for this CFS, to examine mothers' child feeding practices with and acceptance of the WSB++, and to identify potential barriers to adherence. Our results suggest WSB++ is an acceptable CFS in rural Bangladesh and the requirement for mothers to cook WSB++ at home is unlikely to be a barrier to its daily use as a CFS in this population.

Polymer/Polymer Blend Solar Cells Using Tetraazabenzodifluoranthene Diimide Conjugated Polymers as Electron Acceptors

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

Li, Haiyan; Hwang, Ye-Jin; Earmme, Taeshik

2015-03-02

Two n-type semiconducting polymers with alternating arylene (thiophene or selenophene)–tetraazabenzodifluoranthene diimide (BFI) donor–acceptor architecture have been investigated as new electron acceptors in polymer/polymer blend solar cells. The new selenophene-linked polymer, PBFI-S, has a significantly smaller optical band gap (1.13 eV) than the thiophene-linked PBFI-T (1.38 eV); however, both polymers have similar HOMO/LUMO energy levels determined from cyclic voltammetry. Blends of PBFI-T with the thiazolothiazole–dithienylsilole donor polymer (PSEHTT) gave a 2.60% power conversion efficiency (PCE) with a 7.34 mA/cm2 short-circuit current. In contrast, PBFI-S:PSEHTT blends had a 0.75% PCE with similarly reduced photocurrent and external quantum efficiency. Reduced free energy formore » charge transfer and reduced bulk electron mobility in PBFI-S:PSEHTT blends compared to PBFI-T:PSEHTT blends as well as significant differences in bulk film morphology are among the reasons for the large loss in efficiency in PBFI-S:PSEHTT blend solar cells.« less

High-performance ternary blend polymer solar cells involving both energy transfer and hole relay processes.

PubMed

Lu, Luyao; Chen, Wei; Xu, Tao; Yu, Luping

2015-06-04

The integration of multiple materials with complementary absorptions into a single junction device is regarded as an efficient way to enhance the power conversion efficiency (PCE) of organic solar cells (OSCs). However, because of increased complexity with one more component, only limited high-performance ternary systems have been demonstrated previously. Here we report an efficient ternary blend OSC with a PCE of 9.2%. We show that the third component can reduce surface trap densities in the ternary blend. Detailed studies unravel that the improved performance results from synergistic effects of enlarged open circuit voltage, suppressed trap-assisted recombination, enhanced light absorption, increased hole extraction, efficient energy transfer and better morphology. The working mechanism and high device performance demonstrate new insights and design guidelines for high-performance ternary blend solar cells and suggest that ternary structure is a promising platform to boost the efficiency of OSCs.

The rationale for consuming protein blends in sports nutrition.

PubMed

Paul, Gregory L

2009-08-01

Protein is considered by many to be the most important macronutrient for humans because of the numerous roles protein plays in the body. Protein needs have been compared across several population groups, including athletes and other exercising individuals. Many researchers have compared the effects of ingesting animal and vegetable protein sources and their implications on sports performance. Recently, blends of dairy protein and soy protein have appeared in commercial sports nutrition products such as nutrition bars and ready-to-drink and powdered beverages. This review will focus on the potential nutritional advantages of combining whey protein, casein, and isolated soy protein.

Improved plaque materials for aerospace nickel-cadmium cells

NASA Technical Reports Server (NTRS)

Luksha, E.; Gordy, D. J.

1971-01-01

Improved cadmium electrode substrates with precisely controlled microstructures for possible use in aerospace nickel-cadmium cells were prepared. The preparative technique was a powder metallurgical process in which a fugitive pore-former and a nickel powder were blended, then isostatically compacted, and subsequently sintered. Cadmium electrodes prepared from such substrates were cycle tested using an accelerated tortuous test regime. It was discovered that plaques of 60% or 80% porosity prepared with a 25 micron pore-former were better than state-of-the-art electrodes in terms of efficienty and/or mechanical strength. The 60% structures were particularly outstanding in this respect in that they had efficiencies only 5-10 percentage points lower than state-of-the-art electrodes and vastly superior mechanical properties. This added strength was observed to eliminate cracking and physical degradation of the electrodes during processing and cycling. The cadmium electrodes prepared from the 80% porous substrates proved to be the best electrodes made during the course of the work from the point of view of highest efficiency. Three-point bend tests were used to measure mechanical properties of the plaques produced and also as a general characterization tool. In addition, the BET surface areas of selected specimens was determined. The SEM was used for judging microscopic uniformity and quantitatively determining the induced pore size and various other fine structures in the substrates. The technique of X-ray radiography was used to follow the bulk uniformity of the substrates at various stages of their processing.

Co-gasification of pine and oak biochar with sub-bituminous coal in carbon dioxide.

PubMed

Beagle, E; Wang, Y; Bell, D; Belmont, E

2018-03-01

Pine and oak biochars derived as byproducts of demonstration-scale pyrolysis, and blends of these two feedstocks with Powder River Basin coal, were gasified in a carbon dioxide environment using a modified drop tube reactor (MDTR) and a thermogravimetric analyzer (TGA). The impact of gasification temperature on conversion kinetics was evaluated from the temporal evolution of major product gases in the MDTR as measured using a mass spectrometer. Random pore modeling was conducted to simulate gasification in the MDTR with favorable results. The MDTR and TGA were used to conduct gasification for assessment of non-linear additive effects in the blends. Additive analysis of the blends showed deviation from the experimental blend results, indicating inhibiting effects of co-gasifying the biochar and coal. Inhibitory effects are more significant for oak than pine and more pronounced in the TGA at lower gasification temperatures. Results are discussed in the context of feedstock and reactor type. Copyright © 2017 Elsevier Ltd. All rights reserved.

Enrichment of rice-based extrudates with Cactus Opuntia dillenii seed powder: a novel source of fiber and antioxidants.

PubMed

Rayan, Ahmed M; Morsy, Noha E; Youssef, Khaled M

2018-02-01

The present study investigated the effects of adding the powder of cactus Opuntia dillenii ( O. dillenii ) seeds on the functional properties, fiber, antioxidants and acceptability of rice-based extrudates. The control blend consisting basically of rice flour was replaced with O. dillenii seed powder at 2, 4, 6, 8, 10, 15 and 20% then extruded at the optimum processing conditions. The extruded products were evaluated for their chemical composition, functional properties, color attributes, antioxidant activity and sensory characteristics. The results revealed that adding O. dillenii seeds powder enhanced the fiber, phenolics, flavonoid contents and antioxidant activity of extrudates. Expansion, bulk density and breaking strength were significantly decreased, while water absorption index, water solubility index and oil absorption index were significantly increased compared to the control. Furthermore, the mean scores of sensory evaluation indicated clear improvements in all tested sensory attributes, which significantly increased by increasing the level of O. dillenii seed powder up to 15%. The results confirmed that O. dillenii seed powder could be incorporated in rice to develop snack products of acceptable functional, nutritional and sensory properties.

Evaluation of drug-carrier interactions in quaternary powder mixtures containing perindopril tert-butylamine and indapamide.

PubMed

Voelkel, Adam; Milczewska, Kasylda; Teżyk, Michał; Milanowski, Bartłomiej; Lulek, Janina

2016-04-30

Interactions occurring between components in the quaternary powder mixtures consisting of perindopril tert-butylamine, indapamide (active pharmaceutical ingredients), carrier substance and hydrophobic colloidal silica were examined. Two grades of lactose monohydrate: Spherolac(®) 100 and Granulac(®) 200 and two types of microcrystalline cellulose: M101D+ and Vivapur(®) 102 were used as carriers. We determined the size distribution (laser diffraction method), morphology (scanning electron microscopy) and a specific surface area of the powder particles (by nitrogen adsorption-desorption). For the determination of the surface energy of powder mixtures the method of inverse gas chromatography was applied. Investigated mixtures were characterized by surface parameters (dispersive component of surface energy, specific interactions parameters, specific surface area), work of adhesion and cohesion as well as Flory-Huggins parameter χ23('). Results obtained for all quaternary powder mixtures indicate existence of interactions between components. The strongest interactions occur for both blends with different types of microcrystalline cellulose (PM-1 and PM-4) while much weaker ones for powder mixtures with various types of lactose (PM-2 and PM-3). Published by Elsevier B.V.

High Strength Carbide-Based Fibrous Monolith Materials for Solid Rocket Nozzles

DTIC Science & Technology

2008-02-19

individual powders are blended with thermoplastic melt-extrudable polymer binders and plasticizers , using a high shear mixer (Brabender Technologie Inc...Ethylene Ethyl Acrylate, EEA DuPont MFI 1.5 and 20 DPDA 9169 NT Stearic Acid Crompton Hystrene 97 18 NF FG 65 References 1. J. B

21 CFR 172.695 - Xanthan gum.

Code of Federal Regulations, 2011 CFR

2011-04-01

... polysaccharide gum derived from Xanthomonas campestris by a pure-culture fermentation process and purified by... 1.0 gram of the powdered polysaccharide to be tested. Add the blend slowly (approximately 1/2 minute... polysaccharide to be tested in 200 milliliters of distilled water previously heated to 80 °C (omit the locust...

21 CFR 172.695 - Xanthan gum.

Code of Federal Regulations, 2012 CFR

2012-04-01

... polysaccharide gum derived from Xanthomonas campestris by a pure-culture fermentation process and purified by... 1.0 gram of the powdered polysaccharide to be tested. Add the blend slowly (approximately 1/2 minute... polysaccharide to be tested in 200 milliliters of distilled water previously heated to 80 °C (omit the locust...

21 CFR 172.695 - Xanthan gum.

Code of Federal Regulations, 2013 CFR

2013-04-01

... polysaccharide gum derived from Xanthomonas campestris by a pure-culture fermentation process and purified by... 1.0 gram of the powdered polysaccharide to be tested. Add the blend slowly (approximately 1/2 minute... polysaccharide to be tested in 200 milliliters of distilled water previously heated to 80 °C (omit the locust...

21 CFR 172.695 - Xanthan gum.

Code of Federal Regulations, 2010 CFR

2010-04-01

... polysaccharide gum derived from Xanthomonas campestris by a pure-culture fermentation process and purified by... 1.0 gram of the powdered polysaccharide to be tested. Add the blend slowly (approximately 1/2 minute... polysaccharide to be tested in 200 milliliters of distilled water previously heated to 80 °C (omit the locust...

Influence of stearic acid on the structure and rheological behavior of injection-molded ZTA suspensions

NASA Astrophysics Data System (ADS)

Lin, Cong; Wang, Bo; Cheng, Yao; Wang, Cao

2013-01-01

The zirconia-toughened-alumina (ZTA) composite powder was exposed to a prior ball milling treatment with a small amount of stearic acid (SA) before the traditional blending process. The effect of different amounts of stearic acid on surface properties of the powder, the particle size distribution of the powder, and the rheological properties of the suspension were systematically studied within the design of experiments. Fourier transformation infrared spectroscopy (FTIR) analysis was used to prove the chemical interaction between the stearic acid and the ZTA powder. The effects of SA content on the particle sizes and their distribution were carefully examined. Rheological properties such as viscosity, yield stress, and power law exponent of the suspensions were determined within a temperature range of 140-170 °C. The optimal content of SA to improve the properties of the suspensions was found to be 3 wt.%.

The effect of DEB powder processing on thermal cell performance

NASA Astrophysics Data System (ADS)

Szwarc, R.; Walton, R. D.

During the last twenty years, the system Ca/LiCl-KCl-CaCrO4/Fe has provided the basis for thermal batteries designed for military applications. In connection with greater performance demands, investigations are being conducted concerning the effect of catholyte processing on thermal cell performance. The catholyte layer is composed of three components including the depolarizer (D), CaCrO4, the electrolyte (E), LiCl-KCl eutectic, and the binder (B), finely divided SiO2. The catholyte layer or DEB pellets are produced by blending these components, fusing, pulverizing the cake, and hydrostatically pressing the powder into pellets. A description is given of ten powders which were prepared for the reported study. It was found that the procedure used in powder processing affects the capacity, but not its voltage. Increasing the prebake temperature for CaCrO4 from 400 to 600 C resulted in an increase in capacity.

EFFECTS OF COFIRING LIGNIN AND BIOSOLIDS WITH COAL ON FIRESIDE PERFORMANCE AND COMBUSTION PRODUCTS

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

Kevin C. Galbreath

2002-08-01

Lignin, derived from municipal solid waste and biosolid feedstocks using Masada Resource Group's patented CES OxyNol{trademark} process, and acidified biosolids were evaluated as supplemental fuels with coal for producing steam and electricity. Tests were conducted in a pilot-scale (550,000-Btu/hr [580-MJ/hr]) combustion system to evaluate the effects of coal characteristics, blend mixture (on a dry wt% basis) and furnace exit gas temperature (FEGT) on boiler heat-exchange surface slagging and fouling, NO{sub x} and SO{sub x} production, fly ash characteristics, and combustion efficiency. The effects of blending lignin and acidified biosolids with coal on fuel handling and pulverization characteristics were also addressed.more » An 80 wt% Colorado--20 wt% subbituminous Powder River Basin coal blend from the Tennessee Valley Authority Colbert Steam Plant, hereafter referred to as the Colbert coal, and a bituminous Pittsburgh No. 8 coal were tested. The lignin and acidified biosolids were characterized by possessing higher moisture content and lower carbon, hydrogen, and heating values relative to the coals. Ash contents of the fuels were similar. The lignin also possessed higher concentrations of TiO{sub 2}, CaO, and SO{sub 3} and lower concentrations of SiO{sub 2}, Al{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}, K{sub 2}O, and N relative to the coals. The sulfur content of lignin could be reduced through a more thorough washing and drying of the lignin in an efficient commercial-scale dewatering device. Acidified biosolids were distinguished by higher concentrations of P{sub 2}O{sub 5} and MgO and lower SiO{sub 2} and Al{sub 2}O{sub 3} relative to the other fuels. Trace element concentrations, especially for Cr, Pb, Hg, and Ni, were generally greater in the lignin and acidified biosolid fuels relative to the Colbert coal. Maximum trace element emission factors were calculated for 95:5 Colbert coal--lignin and 90:5:5 Colbert coal--lignin--acidified biosolid blends and compared to U.S. Environmental Protection Agency emission factors for pulverized coal-fired units that are unequipped with pollution control devices. Calculated maximum trace element emission factors for the fuel blends were generally less than or within the range of those for the uncontrolled coal-fired units, except for Cr and Pb which were greater.« less

Contrasting performance of donor-acceptor copolymer pairs in ternary blend solar cells and two-acceptor copolymers in binary blend solar cells.

PubMed

Khlyabich, Petr P; Rudenko, Andrey E; Burkhart, Beate; Thompson, Barry C

2015-02-04

Here two contrasting approaches to polymer-fullerene solar cells are compared. In the first approach, two distinct semi-random donor-acceptor copolymers are blended with phenyl-C61-butyric acid methyl ester (PC61BM) to form ternary blend solar cells. The two poly(3-hexylthiophene)-based polymers contain either the acceptor thienopyrroledione (TPD) or diketopyrrolopyrrole (DPP). In the second approach, semi-random donor-acceptor copolymers containing both TPD and DPP acceptors in the same polymer backbone, termed two-acceptor polymers, are blended with PC61BM to give binary blend solar cells. The two approaches result in bulk heterojunction solar cells that have the same molecular active-layer components but differ in the manner in which these molecular components are mixed, either by physical mixing (ternary blend) or chemical "mixing" in the two-acceptor (binary blend) case. Optical properties and photon-to-electron conversion efficiencies of the binary and ternary blends were found to have similar features and were described as a linear combination of the individual components. At the same time, significant differences were observed in the open-circuit voltage (Voc) behaviors of binary and ternary blend solar cells. While in case of two-acceptor polymers, the Voc was found to be in the range of 0.495-0.552 V, ternary blend solar cells showed behavior inherent to organic alloy formation, displaying an intermediate, composition-dependent and tunable Voc in the range from 0.582 to 0.684 V, significantly exceeding the values achieved in the two-acceptor containing binary blend solar cells. Despite the differences between the physical and chemical mixing approaches, both pathways provided solar cells with similar power conversion efficiencies, highlighting the advantages of both pathways toward highly efficient organic solar cells.

Performance Using Bamboo Fiber Ash Concrete as Admixture Adding Superplasticizer

NASA Astrophysics Data System (ADS)

Vasudevan, Gunalaan

2017-06-01

The increasing demand on natural resources for housing provisions in developing countries have called for sourcing and use of sustainable local materials for building and housing delivery. Natural materials to be considered sustainable for building construction should be ‘green’ and obtained from local sources, including rapidly renewable plant materials like palm fronds and bamboo, recycled materials and other products that are reusable and renewable. Each year, tens of millions of tons of bamboo are utilized commercially, generating a vast amount of waste. Besides that, bamboo fiber is easy availability, low density, low production cost and satisfactory mechanical properties. One solution is to activate this waste by using it as an additive admixture in concrete to keep it out of landfills and save money on waste disposal. The research investigates the mechanical and physical properties of bamboo fiber powder in a blended Portland cement. The structural value of the bamboo fiber powder in a blended Portland cement was evaluated with consideration for its suitability in concrete. Varied percentage of bamboo fiber powder (BFP) at 0%, 5%, 10%, 15%, and 20% as an admixture in 1:2:4 concrete mixes. The workability of the mix was determined through slump; standard consistency test was carried on the cement. Compressive strength of hardened cured (150 x 150 x 150) mm concrete cubes at 7days, 14days and 28days were tested.

Fabrication of Natural Uranium UO 2 Disks (Phase II): Texas A&M Work for Others Summary Document

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

Gerczak, Tyler J.; Baldwin, Charles A.; Schmidlin, Joshua E.

The steps to fabricate natural UO 2 disks for an irradiation campaign led by Texas A&M University are outlined. The process was initiated with stoichiometry adjustment of parent, U 3O 8 powder. The next stage of sample preparation involved exploratory pellet pressing and sintering to achieve the desired natural UO 2 pellet densities. Ideal densities were achieved through the use of a bimodal powder size blend. The steps involved with disk fabrication are also presented, describing the coring and thinning process executed to achieve final dimensionality.

High-performance ternary blend polymer solar cells involving both energy transfer and hole relay processes

DOE PAGES

Lu, Luyao; Chen, Wei; Xu, Tao; ...

2015-06-04

The integration of multiple materials with complementary absorptions into a single junction device is regarded as an efficient way to enhance the power conversion efficiency (PCE) of organic solar cells (OSCs). However, because of increased complexity with one more component, only limited high-performance ternary systems have been demonstrated previously. Here we report an efficient ternary blend OSC with a PCE of 9.2%. We show that the third component can reduce surface trap densities in the ternary blend. Detailed studies unravel that the improved performance results from synergistic effects of enlarged open circuit voltage, suppressed trap-assisted recombination, enhanced light absorption, increasedmore » hole extraction, efficient energy transfer and better morphology. As a result, the working mechanism and high device performance demonstrate new insights and design guidelines for high-performance ternary blend solar cells and suggest that ternary structure is a promising platform to boost the efficiency of OSCs.« less

Thiophene dendrimer-based low donor content solar cells

NASA Astrophysics Data System (ADS)

Stoltzfus, Dani M.; Ma, Chang-Qi; Nagiri, Ravi C. R.; Clulow, Andrew J.; Bäuerle, Peter; Burn, Paul L.; Gentle, Ian R.; Meredith, Paul

2016-09-01

Low donor content solar cells containing polymeric and non-polymeric donors blended with fullerenes have been reported to give rise to efficient devices. In this letter, we report that a dendrimeric donor can also be used in solution-processed low donor content devices when blended with a fullerene. A third generation dendrimer containing 42 thiophene units (42T) was found to give power conversion efficiencies of up to 3.5% when blended with PC70BM in optimized devices. The best efficiency was measured with 10 mole percent (mol. %) of 42T in PC70BM and X-ray reflectometry showed that the blends were uniform. Importantly, while 42T comprised 10 mol. % of the film, it made up 31% of the film by volume. Finally, it was found that solvent annealing was required to achieve the largest open circuit voltage and highest device efficiencies.

Blending Gelators to Tune Gel Structure and Probe Anion-Induced Disassembly

PubMed Central

Foster, Jonathan A; Edkins, Robert M; Cameron, Gary J; Colgin, Neil; Fucke, Katharina; Ridgeway, Sam; Crawford, Andrew G; Marder, Todd B; Beeby, Andrew; Cobb, Steven L; Steed, Jonathan W

2014-01-01

Blending different low molecular weight gelators (LMWGs) provides a convenient route to tune the properties of a gel and incorporate functionalities such as fluorescence. Blending a series of gelators having a common bis-urea motif, and functionalised with different amino acid-derived end-groups and differing length alkylene spacers is reported. Fluorescent gelators incorporating 1-and 2-pyrenyl moieties provide a probe of the mixed systems alongside structural and morphological data from powder diffraction and electron microscopy. Characterisation of the individual gelators reveals that although the expected α-urea tape motif is preserved, there is considerable variation in the gelation properties, molecular packing, fibre morphology and rheological behaviour. Mixing of the gelators revealed examples in which: 1) the gels formed separate, orthogonal networks maintaining their own packing and morphology, 2) the gels blended together into a single network, either adopting the packing and morphology of one gelator, or 3) a new structure not seen for either of the gelators individually was created. The strong binding of the urea functionalities to anions was exploited as a means of breaking down the gel structure, and the use of fluorescent gel blends provides new insights into anion-mediated gel dissolution. PMID:24302604

In-line and Real-time Monitoring of Resonant Acoustic Mixing by Near-infrared Spectroscopy Combined with Chemometric Technology for Process Analytical Technology Applications in Pharmaceutical Powder Blending Systems.

PubMed

Tanaka, Ryoma; Takahashi, Naoyuki; Nakamura, Yasuaki; Hattori, Yusuke; Ashizawa, Kazuhide; Otsuka, Makoto

2017-01-01

Resonant acoustic ® mixing (RAM) technology is a system that performs high-speed mixing by vibration through the control of acceleration and frequency. In recent years, real-time process monitoring and prediction has become of increasing interest, and process analytical technology (PAT) systems will be increasingly introduced into actual manufacturing processes. This study examined the application of PAT with the combination of RAM, near-infrared spectroscopy, and chemometric technology as a set of PAT tools for introduction into actual pharmaceutical powder blending processes. Content uniformity was based on a robust partial least squares regression (PLSR) model constructed to manage the RAM configuration parameters and the changing concentration of the components. As a result, real-time monitoring may be possible and could be successfully demonstrated for in-line real-time prediction of active pharmaceutical ingredients and other additives using chemometric technology. This system is expected to be applicable to the RAM method for the risk management of quality.

Stability of Metronidazole Suspensions.

PubMed

Donnelly, Ronald F; Ying, James

2015-01-01

Metronidazole is an antiprotozoal agent used in the treatment of bacterial and protozoal anaerobic infections. The objectives of this study were to develop concentrated metronidazole suspensions that are inexpensive and easy to prepare and determine the stability of these suspensions after storage in amber polyvinyl chloride bottles at room temperature (23°C) and under refrigeration (5°C). Metronidazole suspensions (50 mg/mL) were prepared from powder using Ora-Blend or simple syrup as the vehicles. Samples were collected in triplicate from each container on days 0, 7, 14, 28, 56, and 93. Samples were assayed using a high-performance liquid chromatography method that had been validated as stability indicating. Color, change in physical appearance, and pH were also monitored at each time interval. There was no apparent change in color or physical appearance. The pH values changed by less than 0.20 units over the 93 days. The stability of metronidazole suspensions compounded from United States Pharmacopeia powder using Ora-Blend or simple syrup and packaged in amber polyvinyl chloride bottles was determined to be 93 days when stored at either room temperature or under refrigeration.

Synthesis of structured lipid enriched with omega fatty acids and sn-2 palmitic acid by enzymatic esterification and its incorporation in powdered infant formula.

PubMed

Nagachinta, Supakana; Akoh, Casimir C

2013-05-08

Structured lipid (SL) enriched with arachidonic (ARA) and docosahexaenoic (DHA) acids was produced from tripalmitin using Lipozyme TL IM. The effects of acyl donors, that is, free fatty acids vs fatty acid ethyl esters, on the reactions were compared. The highest total incorporation of ARA and DHA was obtained when the reaction continued for 24 h, at a substrate mole ratio of 9, using free fatty acids as acyl donors (acidolysis). The SL prepared by a large-scale acidolysis reaction contained 17.69 ± 0.09% total ARA, 10.75 ± 0.15% total DHA, and 48.53 ± 1.40% sn-2 palmitic acid. SL thermograms exhibited multiple peaks indicating complexity of the triacylglycerol (TAG) distribution. RP-HPLC analysis of SL revealed nine of 26 TAG molecular species that were similar to those of human milk fat. Powdered infant formulas containing the SL were prepared by wet-mixing/spray-drying and dry-blending methods. Formula prepared with microencapsulated SL and the dry-blending method had better oxidative stability and color quality.

Biodegradation of diesel/biodiesel blends by a consortium of hydrocarbon degraders: effect of the type of blend and the addition of biosurfactants.

PubMed

Owsianiak, Mikołaj; Chrzanowski, Łukasz; Szulc, Alicja; Staniewski, Jacek; Olszanowski, Andrzej; Olejnik-Schmidt, Agnieszka K; Heipieper, Hermann J

2009-02-01

Biodegradation experiments for diesel/biodiesel blends in liquid cultures by-petroleum degrading microbial consortium showed that for low amendments of biodiesel (10%) the overall biodegradation efficiency of the mixture after seven days was lower than for petroleum diesel fuel. Preferential usage of methyl esters in the broad biodiesel concentration range and diminished biodegradation of petroleum hydrocarbons for 10% biodiesel blend was confirmed. Rhamnolipids improved biodegradation efficiency only for blends with low content of biodiesel. Emulsion formation experiments showed that biodiesel amendments significantly affected dispersion of fuel mixtures in water. The presence of rhamnolipids biosurfactant affected stability of such emulsions and altered cell surface properties of tested consortium.

Hemostatic potential of natural/synthetic polymer based hydrogels crosslinked by gamma radiation

NASA Astrophysics Data System (ADS)

Barba, Bin Jeremiah D.; Tranquilan-Aranilla, Charito; Abad, Lucille V.

2016-01-01

Various raw materials and hydrogels prepared from their combination were assessed for hemostatic capability using swine whole blood clotting analysis. Initial screening showed efficient coagulative properties from κ-carrageenan and its carboxymethylated form, and α-chitosan, even compared to commercial products like QuikClot Zeolite Powder. Blending natural and synthetic polymers formed into hydrogels using gamma radiation produced materials with improved properties. KC and CMKC hydrogels were found to have the lowest blood clotting index in granulated form and had the higher capacity for platelet adhesion in foamed form compared to GelFoam. Possible mechanisms involved in the evident thrombogenicity of the materials include adsorption of platelets and related proteins that aid in platelet activation (primary hemostasis), absorption of water to concentrate protein factors that control the coagulation cascade, contact activation by its negatively charged surface and the formation of gel-blood clots.

Polymer powders for selective laser sintering (SLS)

NASA Astrophysics Data System (ADS)

Schmid, Manfred; Amado, Antonio; Wegener, Konrad

2015-05-01

Selective Laser Sintering (SLS) is close to be accepted as a production technique (Additive Manufacturing). However, one problem limiting employment of SLS for additive manufacturing in a wide-ranging industrial scope is the narrow variety of applicable polymers. The commonly applied SLS powder to date is polyamide 12 (PA 12). PA 12 or ccompounds of PA 12 (dry blends) are approximately 90 % of complete industrial consumption. The remaining small quantity is distributed on polyamide 11 (PA11) and some other `exotic' polymers (TPU, PEBA, P(E)EK). Industry is awaiting commodity polymers like polypropylene (PP) or polyethylene (PE) crucial to open new market segments. But several approaches launching those polymers failed. But what are the reasons for the difficulties in developing new SLS powders? The contribution is to answer this and highlights the combination of intrinsic and extrinsic polymer properties necessary to generate a polymer powder promising for SLS application. Particle shape, powder distribution, thermal, rheological and optical requirements must be considered and only a particularly controlled property combination leads to successful SLS implementation. Thermal behavior, particle shape and -distribution is discussed in detail, although the other properties can't be disregarded for providing new commercially successful SLS powder finally.

Mechanical behaviour of pressed and sintered CP Ti and Ti-6Al-7Nb alloy obtained from master alloy addition powder.

PubMed

Bolzoni, L; Weissgaerber, T; Kieback, B; Ruiz-Navas, E M; Gordo, E

2013-04-01

The Ti-6Al-7Nb alloy was obtained using the blending elemental approach with a master alloy and elemental titanium powders. Both the elemental titanium and the Ti-6Al-7Nb powders were characterised using X-ray diffraction, differential thermal analysis and dilatometry. The powders were processed using the conventional powder metallurgy route that includes uniaxial pressing and sintering. The trend of the relative density with the sintering temperature and the microstructural evolution of the materials sintered at different temperatures were analysed using scanning electron microscopy and X-ray diffraction. A minimum sintering temperature of 1200°C has to be used to ensure the homogenisation of the alloying elements and to obtain a pore structure composed of spherical pores. The sintered samples achieve relative density values that are typical for powder metallurgy titanium and no intermetallic phases were detected. Mechanical properties comparable to those specified for wrought Ti-6Al-7Nb medical devices are normally obtained. Therefore, the produced materials are promising candidates for load bearing applications as implant materials. Copyright © 2013 Elsevier Ltd. All rights reserved.

Influence of attrition milling on nano-grain boundaries

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

Rawers, J.; Cook, D.

1999-03-01

Nanostructured materials have a relatively large proportion of their atoms associated with the grain boundary, and the method used to develop the nano-grains has a strong influence on the resulting grain boundary structure. In this study, attrition milling iron powders and blends of iron powders produced micron-size particles composed of nano-size grains. Mechanical cold-working powder resulted in dislocation generation, multiplication, and congealing that produced grain refinement. As the grain size approached nano-dimensions, dislocations were no longer sustained within the grain and once generated, rapidly diffused to the grain boundary. Dislocations on the grain boundary strained the local lattice structure which,more » as the grain size decreased, became the entire grain. Mechanical alloying of substitutional aluminium atoms into iron powder resulted in the aluminium atoms substituting for iron atoms in the grain boundary cells and providing a grain boundary structure similar to that of the iron powder processed in argon. Attrition milling iron powder in nitrogen gas resulted in nitrogen atoms being adsorbed onto the particle surface. Continued mechanical milling infused the nitrogen atoms into interstitial lattice sites on the grain boundary which also contributed to expanding and straining the local lattice.« less

Powder Processing of High Temperature Cermets and Carbides at Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Salvail, Pat; Panda, Binayak; Hickman, Robert R.

2007-01-01

The Materials and Processing Laboratory at NASA Marshall Space Flight Center is developing Powder Metallurgy (PM) processing techniques for high temperature cermet and carbide material consolidation. These new group of materials would be utilized in the nuclear core for Nuclear Thermal Rockets (NTR). Cermet materials offer several advantages for NTR such as retention of fission products and fuels, better thermal shock resistance, hydrogen compatibility, high thermal conductivity, and high strength. Carbide materials offer the highest operating temperatures but are sensitive to thermal stresses and are difficult to process. To support the effort, a new facility has been setup to process refractory metal, ceramic, carbides and depleted uranium-based powders. The facility inciudes inert atmosphere glove boxes for the handling of reactive powders, a high temperature furnace, and powder processing equipment used for blending, milling, and sieving. The effort is focused on basic research to identify the most promising compositions and processing techniques. Several PM processing methods including Cold and Hot Isostatic Pressing are being evaluated to fabricate samples for characterization and hot hydrogen testing.

Performance indicators for carrier-based DPIs: Carrier surface properties for capsule filling and API properties for in vitro aerosolisation.

PubMed

Faulhammer, E; Zellnitz, S; Wutscher, T; Stranzinger, S; Zimmer, A; Paudel, A

2018-01-30

This study investigates engineered carrier, as well as engineered API particles, and shows that there are distinct performance indicators of particle engineering for carrier-based dry powder inhalers (DPIs). Spray dried (SDSS) and jet-milled (JMSS) salbutamol sulphate (SS) was blended with untreated α-lactose monohydrate (LAC_R) and α-lactose monohydrate engineered (LAC_E). Subsequent capsule filling was performed with different process settings on a dosator nozzle capsule filling machine in order to reach a target fill weight of 20-25 mg. To evaluate the performance of the different mixtures, in vitro lung deposition experiments were carried out with a next generation impactor, the emitted dose (ED) and fine particle fraction (FPF) were calculated based on the specification of the European pharmacopoeia. The FPF of micronised powder blends is significantly higher (20%) compared to the FPF of spray dried blends (5%). Compared to API engineering, carrier engineering had a positive effect on the capsule filling performance (weight variability and mean fill weight) at lower compression ratios (setting 1). Results further showed that higher compression ratios appear to be beneficial in terms of capsule filling performance (higher fill weight and less fill weight variation). Concluding, it can be stated that the carrier engineering, or generally carrier properties, govern downstream processing, whereas the API engineering and API properties govern the aerosolisation performance and thereby significantly affect the dose delivery to the lungs. Copyright © 2017 Elsevier B.V. All rights reserved.

Formulation of a dry powder influenza vaccine for nasal delivery.

PubMed

Garmise, Robert J; Mar, Kevin; Crowder, Timothy M; Hwang, C Robin; Ferriter, Matthew; Huang, Juan; Mikszta, John A; Sullivan, Vincent J; Hickey, Anthony J

2006-03-10

The purpose of this research was to prepare a dry powder vaccine formulation containing whole inactivated influenza virus (WIIV) and a mucoadhesive compound suitable for nasal delivery. Powders containing WIIV and either lactose or trehalose were produced by lyophilization. A micro-ball mill was used to reduce the lyophilized cake to sizes suitable for nasal delivery. Chitosan flakes were reduced in size using a cryo-milling technique. Milled powders were sieved between 45 and 125 microm aggregate sizes and characterized for particle size and distribution, morphology, and flow properties. Powders were blended in the micro-ball mill without the ball. Lyophilization followed by milling produced irregularly shaped, polydisperse particles with a median primary particle diameter of approximately 21 microm and a yield of approximately 37% of particles in the 45 to 125 microm particle size range. Flow properties of lactose and trehalose powders after lyophilization followed by milling and sieving were similar. Cryo-milling produced a small yield of particles in the desired size range (<10%). Lyophilization followed by milling and sieving produced particles suitable for nasal delivery with different physicochemical properties as a function of processing conditions and components of the formulation. Further optimization of particle size and morphology is required for these powders to be suitable for clinical evaluation.

Fabrication of co-continuous poly(ε-caprolactone)/polyglycolide blend scaffolds for tissue engineering

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

Allaf, Rula M.; Rivero, Iris V.; Ivanov, Ilia N.

2015-06-06

The apparent inability of a single biomaterial to meet all the requirements for tissue engineering scaffolds has led to continual research in novel engineered biomaterials. One method to provide new materials and fine-tune their properties is via mixing materials. Here in this study, a biodegradable powder blend of poly(ε-caprolactone) (PCL), polyglycolide (PGA), and poly(ethylene oxide) (PEO) was prepared and three-dimensional interconnected porous PCL/PGA scaffolds were fabricated by combining cryomilling and compression molding/polymer leaching techniques. The resultant porous scaffolds exhibited co-continuous morphologies with ~50% porosity. Mean pore sizes of 24 and 56 μm were achieved by varying milling time. The scaffoldsmore » displayed high mechanical properties and water uptake, in addition to a remarkably fast degradation rate. The results demonstrate the potential of this fabrication approach to obtain PCL/PGA blend scaffolds with interconnected porosity. In general, these results provide significant insight into an approach that will lead to the development of new composites and blends in scaffold manufacturing.« less

Egg Shell and Oyster Shell Powder as Alternatives for Synthetic Phosphate: Effects on the Quality of Cooked Ground Pork Products

PubMed Central

2017-01-01

This study aimed to determine the optimal ratio of natural calcium powders (oyster shell and egg shell calcium) as synthetic phosphate replacers in pork products. Ground pork samples were subjected to six treatments, as follows: control (−) (no phosphate added), control (+) (0.3% phosphate blend added), treatment 1 (0.5% oyster shell calcium powder added), treatment 2 (0.3% oyster shell calcium powder and 0.2% egg shell calcium powder added), treatment 3 (0.2% oyster shell calcium powder and 0.3% egg shell calcium powder added), and treatment 4 (0.5% egg shell calcium powder added). The addition of natural calcium powders resulted in an increase in the pH values of meat products, regardless of whether they were used individually or mixed. The highest cooking loss was observed (p<0.05) in the negative control samples, whereas the cooking loss in samples with natural calcium powder added was similar (p>0.05) to that in the positive control samples. CIE L* values decreased as the amount of added egg shell calcium powder increased. CIE a* values were higher (p<0.05) in samples containing natural calcium powder (treatments 1, 2, 3, and 4) than in the positive control. The combination of oyster shell calcium powder and egg shell powder (treatment 2 or 3) was effective for the improvement of textural properties of the pork products. The findings show that the combined use of 0.2% oyster shell calcium and 0.3% egg shell calcium should enable the replacement of synthetic phosphate in the production of cooked pork products with desirable qualities. PMID:28943770

Printability of calcium phosphate: calcium sulfate powders for the application of tissue engineered bone scaffolds using the 3D printing technique.

PubMed

Zhou, Zuoxin; Buchanan, Fraser; Mitchell, Christina; Dunne, Nicholas

2014-05-01

In this study, calcium phosphate (CaP) powders were blended with a three-dimensional printing (3DP) calcium sulfate (CaSO4)-based powder and the resulting composite powders were printed with a water-based binder using the 3DP technology. Application of a water-based binder ensured the manufacture of CaP:CaSO4 constructs on a reliable and repeatable basis, without long term damage of the printhead. Printability of CaP:CaSO4 powders was quantitatively assessed by investigating the key 3DP process parameters, i.e. in-process powder bed packing, drop penetration behavior and the quality of printed solid constructs. Effects of particle size, CaP:CaSO4 ratio and CaP powder type on the 3DP process were considered. The drop penetration technique was used to reliably identify powder formulations that could be potentially used for the application of tissue engineered bone scaffolds using the 3DP technique. Significant improvements (p<0.05) in the 3DP process parameters were found for CaP (30-110 μm):CaSO4 powders compared to CaP (<20 μm):CaSO4 powders. Higher compressive strength was obtained for the powders with the higher CaP:CaSO4 ratio. Hydroxyapatite (HA):CaSO4 powders showed better results than beta-tricalcium phosphate (β-TCP):CaSO4 powders. Solid and porous constructs were manufactured using the 3DP technique from the optimized CaP:CaSO4 powder formulations. High-quality printed constructs were manufactured, which exhibited appropriate green compressive strength and a high level of printing accuracy. Copyright © 2014 Elsevier B.V. All rights reserved.

Egg Shell and Oyster Shell Powder as Alternatives for Synthetic Phosphate: Effects on the Quality of Cooked Ground Pork Products.

PubMed

Cho, Min Guk; Bae, Su Min; Jeong, Jong Youn

2017-01-01

This study aimed to determine the optimal ratio of natural calcium powders (oyster shell and egg shell calcium) as synthetic phosphate replacers in pork products. Ground pork samples were subjected to six treatments, as follows: control (-) (no phosphate added), control (+) (0.3% phosphate blend added), treatment 1 (0.5% oyster shell calcium powder added), treatment 2 (0.3% oyster shell calcium powder and 0.2% egg shell calcium powder added), treatment 3 (0.2% oyster shell calcium powder and 0.3% egg shell calcium powder added), and treatment 4 (0.5% egg shell calcium powder added). The addition of natural calcium powders resulted in an increase in the pH values of meat products, regardless of whether they were used individually or mixed. The highest cooking loss was observed ( p <0.05) in the negative control samples, whereas the cooking loss in samples with natural calcium powder added was similar ( p >0.05) to that in the positive control samples. CIE L* values decreased as the amount of added egg shell calcium powder increased. CIE a* values were higher ( p <0.05) in samples containing natural calcium powder (treatments 1, 2, 3, and 4) than in the positive control. The combination of oyster shell calcium powder and egg shell powder (treatment 2 or 3) was effective for the improvement of textural properties of the pork products. The findings show that the combined use of 0.2% oyster shell calcium and 0.3% egg shell calcium should enable the replacement of synthetic phosphate in the production of cooked pork products with desirable qualities.

Water–solid interactions in amorphous maltodextrin-crystalline sucrose binary mixtures

PubMed Central

Ghorab, Mohamed K.; Toth, Scott J.; Simpson, Garth J.; Mauer, Lisa J.; Taylor, Lynne S.

2016-01-01

Amorphous and crystalline solids are commonly found together in a variety of pharmaceutical and food products. In this study, the influence of co-formulation of amorphous maltodextrins (MDs) and crystalline sucrose (S) on moisture sorption, deliquescence, and glass transition (Tg) properties of powder blends was investigated. Individual components and binary mixtures of four different molecular weight MDs with sucrose in 1:1 w/w ratios were exposed to various relative humidity (RH) environments and their equilibrium and dynamic moisture contents were monitored. The deliquescence point (RH0) and dissolution behavior of sucrose alone and in blends was also monitored by polarized light microscopy and second harmonic generation imaging. In S:MD blends, the deliquescence RH of sucrose was lower than the RH0 of sucrose alone, and synergistic moisture sorption also occurred at RHs lower than the RH0. Intimate contact of sucrose crystals with the amorphous MDs resulted in complete dissolution of sucrose at RH < RH0. When blends were stored at conditions exceeding the Tg of the individual MDs (25 °C and 60%, 49% and 34%RH for MD21, MD29 and MD40, respectively), the Tg of the blends was lower than that of individual MDs. Thus, co-formulation of amorphous MDs with crystalline sucrose sensitizes the blend to moisture, potentially leading to deleterious changes in the formulation if storage conditions are not adequately controlled. PMID:23477494

Mechanical behaviour of pressed and sintered titanium alloys obtained from prealloyed and blended elemental powders.

PubMed

Bolzoni, L; Esteban, P G; Ruiz-Navas, E M; Gordo, E

2012-10-01

The applicability of irregular prealloyed Ti-6Al-4V powder for the fabrication of titanium products by pressing and sintering and its employment as a master alloy to obtain the Ti-3Al-2.5V alloy was studied. To this end, the starting powders were characterised by dilatometry, differential thermal analysis and XRD. Green samples were obtained by cold uniaxial pressing, and the evolution of the microstructure over the sintering temperature range 900-1400°C was studied. The variation of the final density and mechanical properties with the sintering temperature was considered. Based on the study carried out, it can be stated that more reliable powders are needed to open the titanium market to new applications. A relative density of 95% and diverse microstructural features and mechanical properties equivalent to those of biomedical devices can be obtained by the pressing and sintering route. Copyright © 2012 Elsevier Ltd. All rights reserved.

Influence of debittered, defatted fenugreek seed powder and flaxseed powder on the rheological characteristics of dough and quality of cookies.

PubMed

Metwal, Nirmala; Jyotsna, R; Jeyarani, T; Venkateswara Rao, G

2011-06-01

A functional ingredient mix (FIM) comprising debittered and defatted fenugreek seed powder (70%) and flaxseed powder (30%) was used in cookies. Ash, fat and protein, dough development time, resistance to extension and peak viscosity values increased as the level of FIM increased from 10 to 30% in the blend. Beyond 20% of FIM substitution, the quality characteristics of cookies were adversely affected. Use of soya lecithin produced a significant improvement in the overall quality of the cookies with 20% FIM. Linolenic acid and total dietary fiber content of the cookies with 20% FIM and lecithin contained four times the amount of linolenic acid (2.3%) and double the amount of dietary fiber (13.04%) when compared with the control cookies (0.5% and 6.22%) respectively. Surface scanning electron microscopy of cookies with different levels of FIM from 10 to 30% showed that there was a disruption in the matrix.

Acoustic Emission Analysis of Damage during Compressive Deformation of Amorphous Zr-Based Foams with Aligned, Elongated Pores

NASA Astrophysics Data System (ADS)

Cox, Marie E.; Dunand, David C.

2013-07-01

Acoustic emission methods are used to investigate the evolution of internal microfractural damage during uniaxial compression of amorphous Zr-based foams with aligned, elongated pores. The foams are fabricated by means of densifying a blend of crystalline W powders and amorphous Zr-based powders with two oxygen contents (0.078 and 0.144 wt pct) by warm equal channel angular extrusion, followed by dissolution of the elongated W phase from the fully densified amorphous matrix. For the high-oxygen foams, prior powder boundaries in the amorphous struts promote damage that accumulates during compression, resulting in energy-absorbing properties comparable with the low-oxygen foams without stress-concentrating powder boundaries. The influence of pore orientation on the evolution of microfracture damage and the ability of the foams to accumulate damage without catastrophic failure is also investigated: pores oriented from 24 to 68 deg to the loading direction promote wall bending, resulting in foams with more diffuse damage and better energy-absorbing properties.

Development of Cu Reinforced SiC Particulate Composites

NASA Astrophysics Data System (ADS)

Singh, Harshpreet; Kumar, Lailesh; Nasimul Alam, Syed

2015-02-01

This paper presents the results of Cu-SiCp composites developed by powder metallurgy route and an attempt has been made to make a comparison between the composites developed by using unmilled Cu powder and milled Cu powder. SiC particles as reinforcement was blended with unmilled and as-milled Cu powderwith reinforcement contents of 10, 20, 30, 40 vol. % by powder metallurgy route. The mechanical properties of pure Cu and the composites developed were studied after sintering at 900°C for 1 h. Density of the sintered composites were found out based on the Archimedes' principle. X-ray diffraction of all the composites was done in order to determine the various phases in the composites. Scanning electron microscopy (SEM) and EDS (electron diffraction x-ray spectroscopy) was carried out for the microstructural analysis of the composites. Vickers microhardness tester was used to find out the hardness of the samples. Wear properties of the developed composites were also studied.

Method of producing exfoliated graphite composite compositions for fuel cell flow field plates

DOEpatents

Zhamu, Aruna; Shi, Jinjun; Guo, Jiusheng; Jang, Bor Z

2014-04-08

A method of producing an electrically conductive composite composition, which is particularly useful for fuel cell bipolar plate applications. The method comprises: (a) providing a supply of expandable graphite powder; (b) providing a supply of a non-expandable powder component comprising a binder or matrix material; (c) blending the expandable graphite with the non-expandable powder component to form a powder mixture wherein the non-expandable powder component is in the amount of between 3% and 60% by weight based on the total weight of the powder mixture; (d) exposing the powder mixture to a temperature sufficient for exfoliating the expandable graphite to obtain a compressible mixture comprising expanded graphite worms and the non-expandable component; (e) compressing the compressible mixture at a pressure within the range of from about 5 psi to about 50,000 psi in predetermined directions into predetermined forms of cohered graphite composite compact; and (f) treating the so-formed cohered graphite composite to activate the binder or matrix material thereby promoting adhesion within the compact to produce the desired composite composition. Preferably, the non-expandable powder component further comprises an isotropy-promoting agent such as non-expandable graphite particles. Further preferably, step (e) comprises compressing the mixture in at least two directions. The method leads to composite plates with exceptionally high thickness-direction electrical conductivity.

Compatibilization of HIPS/ABS blends from WEEE by using Styrene-Butadiene Rubber (SBR).

PubMed

Vazquez, Yamila V; Barbosa, Silvia E

2018-07-01

The aim of this work is to develop compatibilization strategies for High Impact Polystyrene (HIPS)/ Acrylonitrile-Butadiene-Styrene (ABS) blends from WEEE in order to add value to these recycled plastics by improving their mechanical performance. Results from a screening study of HIPS/ABS blends compatibilization by the addition of Styrene-Butadiene Rubber (SBR) are presented. Two different weight proportion of HIPS/ABS physical blends were analyzed, 80/20 and 20/80, with three different concentration of SBR: 2, 10 and 20 wt%. Compatibilization efficiency was analyzed from an accurate thermal and mechanical analysis, by comparing each physical blend and corresponding compatibilized blends with SBR. Results were discussed relating glass transition changes with mechanical performance, both aspects were interpreted in terms of blend morphology. Phase and fillers dispersion and distribution as well as SBR amount and its interaction with each phase were accurate analyzed. Compatibilization of HIPS/ABS blends from WEEE with the addition of SBR is effective in blends with HIPS as main component. With the addition of 2 wt% of SBR, strength and toughness have notably increased respect to the corresponding physical blend, 244% and 186% respectively. From this screening study is possible to infer that SBR is a sustainable and efficient compatibilizer of HIPS rich blends allowing to obtain a final blend that can be used as a replacement material of separated resins from WEEE. Copyright © 2018 Elsevier Ltd. All rights reserved.

Powder metallurgy processing and deformation characteristics of bulk multimodal nickel

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

Farbaniec, L., E-mail: lfarban1@jhu.edu; Dirras, G., E-mail: dirras@univ-paris13.fr; Krawczynska, A.

2014-08-15

Spark plasma sintering was used to process bulk nickel samples from a blend of three powder types. The resulting multimodal microstructure was made of coarse (average size ∼ 135 μm) spherical microcrystalline entities (the core) surrounded by a fine-grained matrix (average grain size ∼ 1.5 μm) or a thick rim (the shell) distinguishable from the matrix. Tensile tests revealed yield strength of ∼ 470 MPa that was accompanied by limited ductility (∼ 2.8% plastic strain). Microstructure observation after testing showed debonding at interfaces between the matrix and the coarse entities, but in many instances, shallow dimples within the rim weremore » observed indicating local ductile events in the shell. Dislocation emission and annihilation at grain boundaries and twinning at crack tip were the main deformation mechanisms taking place within the fine-grained matrix as revealed by in-situ transmission electron microscopy. Estimation of the stress from loop's curvature and dislocation pile-up indicates that dislocation emission from grain boundaries and grain boundary overcoming largely contributes to the flow stress. - Highlights: • Bulk multi-modal Ni was processed by SPS from a powder blend. • Ultrafine-grained matrix or rim observed around spherical microcrystalline entities • Yield strength (470 MPa) and ductility (2.8% plastic strain) were measured. • Debonding was found at the matrix/microcrystalline entity interfaces. • In-situ TEM showed twinning, dislocation emission and annihilation at grain boundaries.« less

Porous carbonaceous electrode structure and method for secondary electrochemical cell

DOEpatents

Kaun, Thomas D.

1977-03-08

Positive and negative electrodes are provided as rigid, porous carbonaceous matrices with particulate active material fixedly embedded. Active material such as metal chalcogenides, solid alloys of alkali metal or alkaline earth metals along with other metals and their oxides in particulate form are blended with a thermosetting resin and a solid volatile to form a paste mixture. Various electrically conductive powders or current collector structures can be blended or embedded into the paste mixture which can be molded to the desired electrode shape. The molded paste is heated to a temperature at which the volatile transforms into vapor to impart porosity as the resin begins to cure into a rigid solid structure.

Development of an Efficient Micro-Heat Exchanger: The Integration of Design Processing and Testing

DTIC Science & Technology

2005-11-01

together at high temperatures and cooled to room temperature. Additionally, alumina and zirconia powders have a major difference in densification...efficient heat exchanger. The main problem that needed to be resolved was the fact that the zirconia powders shrink much more than alumina powder...been measured. Our measurement in dimensions verifies that zirconia powders shrink substantially more than alumina powder except CR-15 after final

Uniform-droplet spray forming

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

Blue, C.A.; Sikka, V.K.; Chun, Jung-Hoon

1997-04-01

The uniform-droplet process is a new method of liquid-metal atomization that results in single droplets that can be used to produce mono-size powders or sprayed-on to substrates to produce near-net shapes with tailored microstructure. The mono-sized powder-production capability of the uniform-droplet process also has the potential of permitting engineered powder blends to produce components of controlled porosity. Metal and alloy powders are commercially produced by at least three different methods: gas atomization, water atomization, and rotating disk. All three methods produce powders of a broad range in size with a very small yield of fine powders with single-sized droplets thatmore » can be used to produce mono-size powders or sprayed-on substrates to produce near-net shapes with tailored microstructures. The economical analysis has shown the process to have the potential of reducing capital cost by 50% and operating cost by 37.5% when applied to powder making. For the spray-forming process, a 25% savings is expected in both the capital and operating costs. The project is jointly carried out at Massachusetts Institute of Technology (MIT), Tuffs University, and Oak Ridge National Laboratory (ORNL). Preliminary interactions with both finished parts and powder producers have shown a strong interest in the uniform-droplet process. Systematic studies are being conducted to optimize the process parameters, understand the solidification of droplets and spray deposits, and develop a uniform-droplet-system (UDS) apparatus appropriate for processing engineering alloys.« less

Radiation processed polychloroprene-co-ethylene-propene diene terpolymer blends: Effect of radiation vulcanization on solvent transport kinetics

NASA Astrophysics Data System (ADS)

Dubey, K. A.; Bhardwaj, Y. K.; Chaudhari, C. V.; Kumar, Virendra; Goel, N. K.; Sabharwal, S.

2009-03-01

Blends of polychloroprene rubber (PCR) and ethylene propylene diene terpolymer rubber (EPDM) of different compositions were made and exposed to different gamma radiation doses. The radiation sensitivity and radiation vulcanization efficiency of blends was estimated by gel-content analysis, Charlesby-Pinner parameter determination and crosslinking density measurements. Gamma radiation induced crosslinking was most efficient for EPDM ( p0/ q0 ˜ 0.08), whereas it was the lowest for blends containing 40% PCR ( p0/ q0 ˜ 0.34). The vulcanized blends were characterized for solvent diffusion characteristics by following the swelling dynamics. Blends with higher PCR content showed anomalous swelling. The sorption and permeability of the solvent were not strictly in accordance with each other and the extent of variation in two parameters was found to be a function of blend composition. The Δ G values for solvent diffusion were in the range -2.97 to -9.58 kJ/mol and indicated thermodynamically favorable sorption for all blends. These results were corroborated by dynamic swelling, experimental as well as simulated profiles and have been explained on the basis of correlation between crosslinking density, diffusion kinetics, thermodynamic parameters and polymer-polymer interaction parameter.

Enabling High Efficiency Ethanol Engines

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

Szybist, J.; Confer, K.

2011-03-01

Delphi Automotive Systems and ORNL established this CRADA to explore the potential to improve the energy efficiency of spark-ignited engines operating on ethanol-gasoline blends. By taking advantage of the fuel properties of ethanol, such as high compression ratio and high latent heat of vaporization, it is possible to increase efficiency with ethanol blends. Increasing the efficiency with ethanol-containing blends aims to remove a market barrier of reduced fuel economy with E85 fuel blends, which is currently about 30% lower than with petroleum-derived gasoline. The same or higher engine efficiency is achieved with E85, and the reduction in fuel economy ismore » due to the lower energy density of E85. By making ethanol-blends more efficient, the fuel economy gap between gasoline and E85 can be reduced. In the partnership between Delphi and ORNL, each organization brought a unique and complementary set of skills to the project. Delphi has extensive knowledge and experience in powertrain components and subsystems as well as overcoming real-world implementation barriers. ORNL has extensive knowledge and expertise in non-traditional fuels and improving engine system efficiency for the next generation of internal combustion engines. Partnering to combine these knowledge bases was essential towards making progress to reducing the fuel economy gap between gasoline and E85. ORNL and Delphi maintained strong collaboration throughout the project. Meetings were held regularly, usually on a bi-weekly basis, with additional reports, presentations, and meetings as necessary to maintain progress. Delphi provided substantial hardware support to the project by providing components for the single-cylinder engine experiments, engineering support for hardware modifications, guidance for operational strategies on engine research, and hardware support by providing a flexible multi-cylinder engine to be used for optimizing engine efficiency with ethanol-containing fuels.« less

A novel quantitative analysis method of three-dimensional fluorescence spectra for vegetable oils contents in edible blend oil

NASA Astrophysics Data System (ADS)

Xu, Jing; Wang, Yu-Tian; Liu, Xiao-Fei

2015-04-01

Edible blend oil is a mixture of vegetable oils. Eligible blend oil can meet the daily need of two essential fatty acids for human to achieve the balanced nutrition. Each vegetable oil has its different composition, so vegetable oils contents in edible blend oil determine nutritional components in blend oil. A high-precision quantitative analysis method to detect the vegetable oils contents in blend oil is necessary to ensure balanced nutrition for human being. Three-dimensional fluorescence technique is high selectivity, high sensitivity, and high-efficiency. Efficiency extraction and full use of information in tree-dimensional fluorescence spectra will improve the accuracy of the measurement. A novel quantitative analysis is proposed based on Quasi-Monte-Carlo integral to improve the measurement sensitivity and reduce the random error. Partial least squares method is used to solve nonlinear equations to avoid the effect of multicollinearity. The recovery rates of blend oil mixed by peanut oil, soybean oil and sunflower are calculated to verify the accuracy of the method, which are increased, compared the linear method used commonly for component concentration measurement.

Direct formation of nano-pillar arrays by phase separation of polymer blend for the enhanced out-coupling of organic light emitting diodes with low pixel blurring.

PubMed

Lee, Cholho; Han, Kyung-Hoon; Kim, Kwon-Hyeon; Kim, Jang-Joo

2016-03-21

We have demonstrated a simple and efficient method to fabricate OLEDs with enhanced out-coupling efficiencies and with low pixel blurring by inserting nano-pillar arrays prepared through the lateral phase separation of two immiscible polymers in a blend film. By selecting a proper solvent for the polymer and controlling the composition of the polymer blend, the nano-pillar arrays were formed directly after spin-coating of the polymer blend and selective removal of one phase, needing no complicated processes such as nano-imprint lithography. Pattern size and distribution were easily controlled by changing the composition and thickness of the polymer blend film. Phosphorescent OLEDs using the internal light extraction layer containing the nano-pillar arrays showed a 30% enhancement of the power efficiency, no spectral variation with the viewing angle, and only a small increment in pixel blurring. With these advantages, this newly developed method can be adopted for the commercial fabrication process of OLEDs for lighting and display applications.

Design of organic ternary blends and small-molecule bulk heterojunctions: photophysical considerations

NASA Astrophysics Data System (ADS)

Rajesh, Kallarakkal Ramakrishnan; Paudel, Keshab; Johnson, Brian; Hallani, Rawad; Anthony, John; Ostroverkhova, Oksana

2015-01-01

We explored relationships between photophysical processes and solar cell characteristics in solution-processable bulk heterojunctions (BHJs), in particular: (1) polymer donor:fullerene acceptor:small-molecule (SM) nonfullerene acceptor, (2) polymer donor:SM donor:SM nonfullerene acceptor, and (3) SM donor:SM nonfullerene or fullerene acceptor. Addition of a nonfullerene SM acceptor to "efficient" polymer:fullerene BHJs led to a reduction in power conversion efficiency (PCE), mostly due to decreased charge photogeneration efficiency and increased disorder. By contrast, addition of an SM donor to "inefficient" polymer:SM nonfullerene acceptor BHJs led to a factor of two to three improvement in the PCE, due to improved charge photogeneration efficiency and transport. In most blends, exciplex formation was observed and correlated with a reduced short-circuit current (Jsc) without negatively impacting the open-circuit voltage (Voc). A factor of ˜5 higher PCE was observed in SM donor:fullerene acceptor BHJs as compared to SMBHJs with the same SM donor but nonfullerene acceptor, due to enhanced charge carrier photogeneration in the blend with fullerene. Our study revealed that the HOMO and LUMO energies of molecules comprising a blend are not reliable parameters for predicting Voc of the blend, and an understanding of the photophysics is necessary for interpreting solar cell characteristics and improving the molecular design of BHJs.

Synthesis of a low-band-gap small molecule based on acenaphthoquinoxaline for efficient bulk heterojunction solar cells.

PubMed

Mikroyannidis, J A; Kabanakis, A N; Kumar, Anil; Sharma, S S; Vijay, Y K; Sharma, G D

2010-08-03

A novel small molecule (SM) with a low-band-gap based on acenaphthoquinoxaline was synthesized and characterized. It was soluble in polar solvents such as N,N-dimethylformamide and dimethylacetamide. SM showed broad absorption curves in both solution and thin films with a long-wavelength maximum at 642 nm. The thin film absorption onset was located at 783 nm, which corresponds to an optical band gap of 1.59 eV. SM was blended with PCBM to study the donor-acceptor interactions in the blended film morphology and the photovoltaic response of the bulk heterojunction (BHJ) devices. The cyclic voltammetry measurements of the materials revealed that the HOMO and LUMO levels of SM are well aligned with those of PCBM, allowing efficient photoinduced charge transfer and suitable open circuit voltage, leading to overall power conversion efficiencies (PCEs) of approximately 2.21 and 3.23% for devices with the as-cast and thermally annealed blended layer, respectively. The increase in the PCE with the thermally annealed blend is mainly attributed to the improvement in incident photon to current efficiency (IPCE) and short circuit photocurrent (J(sc)). Thermal annealing leads to an increase in both the crystallinity of the blend and hole mobility, which improves the PCE.

Effect of ethanol-gasoline blends on small engine generator energy efficiency and exhaust emission.

PubMed

Lin, Wen-Yinn; Chang, Yuan-Yi; Hsieh, You-Ru

2010-02-01

This study was focused on fuel energy efficiency and pollution analysis of different ratios of ethanol-gasoline blended fuels (E0, E3, E6, and E9) under different loadings. In this research, the experimental system consisted of a small engine generator, a particulate matter measurement system, and an exhaust gas analyzer system. Different fuels, unleaded gasoline, and ethanol-gasoline blends (E0, E3, E6, and E9) were used to study their effects on the exhaust gas emission and were expressed as thermal efficiency of the small engine generator energy efficiency. The results suggested that particle number concentration increased as the engine loading increased; however, it decreased as the ethanol content in the blend increased. While using E6 as fuel, the carbon monoxide (CO) concentration was less than other fuels (E0, E3, and E9) for each engine loading. The average of CO concentration reduction by using E3, E6, and E9 is 42, 86, and 83%, respectively. Using an ethanol-gasoline blend led to a significant reduction in exhaust emissions by approximately 78.7, 97.5, and 89.46% of the mean average values of hydrocarbons (HCs) with E3, E6, and E9 fuels, respectively, for all engine loadings. Using an ethanol-gasoline blend led to a significant reduction in exhaust emissions by approximately 35, 86, and 77% of the mean average values of nitrogen oxides (NOx) with E3, E6, and E9 fuels, respectively, at each engine loading. The E6 fuel gave the best results of the exhaust emissions, and the E9 fuel gave the best results of the particle emissions and engine performance. The thermal efficiency of the small engine generator increased as the ethanol content in the blend increased and as the engine loading increased.

Properties of flat-pressed wood plastic composites containing fire retardants

Treesearch

Nadir Ayrilmis; Jan. T. Benthien; Heiko Thoemen; Robert H. White

2011-01-01

This study investigated physical, mechanical, and fire properties of the flat-pressed wood plastic composites (WPCs) incorporated with various fire retardants (FRs) [5 or 15% by weight (wt)] at 50 wt % of the wood flour (WF). The WPC panels were made from dry-blended WF, polypropylene (PP) with maleic anhydride grafted PP (2 wt %), and FR powder formulations using a...

Effects of packaging environments on free radicals in gamma-irradiated UHMWPE resin powder blend with vitamin E.

PubMed

Ridley, M D; Jahan, M S

2009-03-15

Ultra-high molecular weight polyethylene (UHMWPE) powder (GUR 1020) was blended with high concentration (20%) of vitamin E (alpha-Tocopherol (alpha-T)) for direct detection of alpha-T radicals in presence of PE radicals. Samples were gamma-irradiated in sealed packages filled with N(2), or in open air. Free radicals were measured in open air environment for 71 days using electron spin resonance (ESR) technique. When irradiated in air, both alpha-T and alpha-T-resin produced identical ESR signals characteristics of tochopheroxyl radicals (alpha-T-O(*)), suggesting that PE radicals are quenched by alpha-T. There was no indication of growth of oxygen-induced radicals (OIR) either. However, when alpha-T-resin was irradiated in N(2), presence of both PE and alpha-T radicals were evident in the ESR spectra. And, OIR were produced by the same samples when they were subsequently exposed to air (for 71 days). Oxidation data recorded 85 days after postirradiation aging in air using Fourier transform infra-red (FTIR) spectroscopy, however, did not show any measurable difference between samples irradiated in N(2) and air.

Flexural properties of ethyl or methyl methacrylate-UDMA blend polymers.

PubMed

Kanie, Takahito; Kadokawa, Akihiko; Arikawa, Hiroyuki; Fujii, Koichi; Ban, Seiji

2010-10-01

Light-curing polyethyl methacrylate (PEMA)-urethane dimethacrylate (UDMA) resins and polymethyl methacrylate (PMMA)-UDMA resins were prepared by two processes. For first step, PEMA or PMMA powders were fully dissolved in ethyl methacrylate (EMA) or methyl methacrylate (MMA) and then the PEMA-EMA/PMMA-MMA mixtures were mixed with UDMA. The flexural properties of cured PEMA-UDMA and PMMA-UDMA polymers were measured using two PEMA (Mw: 300,000-400,000 and 650,000-1,000,000) and three PMMA (Mw: 30,000-60,000, 350,000 and 650,000-1,000,000) powders with different molecular weight, four mixing ratios of PMMA-MMA, and three mixing ratios of PMMA-MMA mixture and UDMA oligomer. Polymers with PMMA(Mw: 350,000) MMA=25/50, and with PMMA(Mw: 350,000)-MMA/UDMA=1/2 and =1/1, showed no-fracture in a flexural test at 1 mm/min and flexural strength and flexural modulus showed no significant difference compared with those of commercially available heat- and self-curing acrylic resins (p>0.01). Within limitation of this investigation, methyl methacrylate-UDMA blend polymer of this composition is available for denture base resin.

Cohesion, Cracking, Dilation, and Flow -- Rheological Behavior of Cohesive Pharmaceutical Powders

NASA Astrophysics Data System (ADS)

Muzzio, Fernando

2007-03-01

Cohesive powders can be loosely defined as systems where the attractive forced between particles exceed the average particle weight. Cohesive powder flow is interesting from a wide range of reasons. Their main characteristic, intermittence, is evidenced both in the interruption of flow out of hoppers (a mundane issue causing great annoyance to industrial practitioners) and in the sudden avalanching of snow and dirt that has terrified and terrified mankind since the dawn of time. At the present time, our ability to predict either of these phenomena (and many more involving cohesive powders) is very limited, primarily due to an incomplete understanding of their constitutive behavior. To wit, consider just a simple fact: a flowing powder never has constant density. Equations describing the relationship between velocity, shear, stress, and density are rudimentary at best. Computational and experimental approaches for characterizing flow behavior are in their infancy. In this talk, I will describe some recent progress achieved at Rutgers by our group. New instruments have been developed to determine simultaneously powder density and cohesive flow effects. Extensive measurements have been carried out focusing on pharmaceutical blends. These results have been used to fine-tune computational models that accurately predict dilation, flow in drums, and flow in hoppers. Impact of these observations for pharmaceutical manufacturing applications will be discussed in some detail.

Power mixture and green body for producing silicon nitride base articles of high fracture toughness and strength

DOEpatents

Huckabee, M.L.; Buljan, S.T.; Neil, J.T.

1991-09-17

A powder mixture and a green body for producing a silicon nitride-based article of improved fracture toughness and strength are disclosed. The powder mixture includes (a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon nitride powder of an average particle size of about 0.2 [mu]m and a surface area of about 8-12m[sup 2]g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 [mu]m and a surface area of about 2-4 m[sup 2]/g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified article an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. The green body is formed from the powder mixture, an effective amount of a suitable oxide densification aid, and an effective amount of a suitable organic binder. No Drawings

Power mixture and green body for producing silicon nitride base & articles of high fracture toughness and strength

DOEpatents

Huckabee, Marvin L.; Buljan, Sergej-Tomislav; Neil, Jeffrey T.

1991-01-01

A powder mixture and a green body for producing a silicon nitride-based article of improved fracture toughness and strength. The powder mixture includes 9a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon mitride powder of an average particle size of about 0.2 .mu.m and a surface area of about 8-12m.sup.2 g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 .mu.m and a surface area of about 2-4 m.sup.2 /g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified articel an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. The green body is formed from the powder mixture, an effective amount of a suitable oxide densification aid, and an effective amount of a suitable organic binder.

Data related to the experimental design for powder bed binder jetting additive manufacturing of silicone.

PubMed

Liravi, Farzad; Vlasea, Mihaela

2018-06-01

The data included in this article provides additional supporting information on our recent publication (Liravi et al., 2018 [1]) on a novel hybrid additive manufacturing (AM) method for fabrication of three-dimensional (3D) structures from silicone powder. A design of experiments (DoE) study has been carried out to optimize the geometrical fidelity of AM-made parts. This manuscript includes the details of a multi-level factorial DOE and the response optimization results. The variation in the temperature of powder-bed when exposed to heat is plotted as well. Furthermore, the effect of blending ratio of two parts of silicone binder on its curing speed was investigated by conducting DSC tests on a silicone binder with 100:2 precursor to curing agent ratio. The hardness of parts fabricated with non-optimum printing conditions are included and compared.

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

Magdalena Zaharia; Veena Sahajwalla; Byong-Chul Kim

The present study investigates the effect of addition of waste rubber tires on the combustion behavior of its blends with coke for carbon injection in electric arc furnace steelmaking. Waste rubber tires were mixed in different proportions with metallurgical coke (MC) (10:90, 20:80, 30:70) for combustion and pyrolysis at 1473 K in a drop tube furnace (DTF) and thermogravimetric analyzer (TGA), respectively. Under experimental conditions most of the rubber blends indicated higher combustion efficiencies compared to those of the constituent coke. In the early stage of combustion the weight loss rate of the blends is much faster compared to thatmore » of the raw coke due to the higher volatile yield of rubber. The presence of rubber in the blends may have had an impact upon the structure during the release and combustion of their high volatile matter (VM) and hence increased char burnout. Measurements of micropore surface area and bulk density of the chars collected after combustion support the higher combustion efficiency of the blends in comparison to coke alone. The surface morphology of the 30% rubber blend revealed pores in the residual char that might be attributed to volatile evolution during high temperature reaction in oxygen atmosphere. Physical properties and VM appear to have a major effect upon the measured combustion efficiency of rubber blends. The study demonstrates that waste rubber tires can be successfully co-injected with metallurgical coke in electric arc furnace steelmaking process to provide additional energy from combustion. 44 refs., 11 figs., 2 tabs.« less

Final Report: Utilizing Alternative Fuel Ignition Properties to Improve SI and CI Engine Efficiency

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

Wooldridge, Margaret; Boehman, Andre; Lavoie, George

Experimental and modeling studies were completed to explore leveraging physical and chemical fuel properties for improved thermal efficiency of internal combustion engines. Fundamental studies of the ignition chemistry of ethanol and iso-octane blends and constant volume spray chamber studies of gasoline and diesel sprays supported the core research effort which used several reciprocating engine platforms. Single cylinder spark ignition (SI) engine studies were carried out to characterize the impact of ethanol/gasoline, syngas (H 2 and CO)/gasoline and other oxygenate/gasoline blends on engine performance. The results of the single-cylinder engine experiments and other data from the literature were used to trainmore » a GT Power model and to develop a knock criteria based on reaction chemistry. The models were used to interpret the experimental results and project future performance. Studies were also carried out using a state of the art, direct injection (DI) turbocharged multi- cylinder engine with piezo-actuated fuel injectors to demonstrate the promising spray and spark timing strategies from single-cylinder engine studies on the multi-cylinder engine. Key outcomes and conclusions of the studies were: 1. Efficiency benefits of ethanol and gasoline fuel blends were consistent and substantial (e.g. 5-8% absolute improvement in gross indicated thermal efficiency (GITE)). 2. The best ethanol/gasoline blend (based on maximum thermal efficiency) was determined by the engine hardware and limits based on component protection (e.g. peak in-cylinder pressure or maximum turbocharger inlet temperature) – and not by knock limits. Blends with <50% ethanol delivered significant thermal efficiency gains with conventional SI hardware while maintain good safety integrity to the engine hardware. 3. Other compositions of fuel blends including syngas (H 2 and CO) and other dilution strategies provided significant efficiency gains as well (e.g. 5% absolute improvement in ITE). 4. When the combination of engine and fuel system is not knock limited, multiple fuel injection events maintain thermal efficiency while improving engine-out emissions (e.g. CO, UHC, and particulate number).« less

Water Atomization of Barium Fluoride: Calcium Fluoride for Enhanced Flow Characteristics of PS304 Feedstock Powder Blend

NASA Technical Reports Server (NTRS)

Stanford, Malcolm K.; DellaCorte, Christopher

2003-01-01

PS304 is a plasma spray deposited solid lubricant coating with feedstock composed of NiCr, Cr2O3, Ag, and BaF2-CaF2 powders. The effects of rounded BaF2-CaF2 particles on the gravity-fed flow characteristics of PS304 feedstock have been investigated. The BaF2-CaF2 powder was fabricated by water atomization using four sets of process parameters. Each of these powders was then characterized by microscopy and classified by screening to obtain 45 to 106 micron particles and added incrementally from 0 to 10 wt% to the other constituents of the PS304 feedstock, namely nichrome, chromia, and silver powders. The relationship between feedstock flow rate, measured with the Hall flowmeter, and concentration of fluorides was found to be linear in each case. The slopes of the lines were between those of the linear relationships previously reported using angular and spherical fluorides and were closer to the relationship predicted using the rule of mixtures. The results offer a fluoride fabrication technique potentially more cost-effective than gas atomization processes or traditional comminution processes.

The effect of native silk fibroin powder on the physical properties and biocompatibility of biomedical polyurethane membrane.

PubMed

Zhuang, Yan; Zhang, Qian; Feng, Jinqi; Wang, Na; Xu, Weilin; Yang, Hongjun

2017-04-01

Naturally derived fibers such as silk fibroin can potentially enhance the biocompatibility of currently used biomaterials. This study investigated the physical properties of native silk fibroin powder and its effect on the biocompatibility of biomedical polyurethane. Native silk fibroin powder with an average diameter of 3 µm was prepared on a purpose-built machine. A simple method of phase inversion was used to produce biomedical polyurethane/native silk fibroin powder hybrid membranes at different blend ratios by immersing a biomedical polyurethane/native silk fibroin powder solution in deionized water at room temperature. The physical properties of the membranes including morphology, hydrophilicity, roughness, porosity, and compressive modulus were characterized, and in vitro biocompatibility was evaluated by seeding the human umbilical vein endothelial cells on the top surface. Native silk fibroin powder had a concentration-dependent effect on the number and morphology of human umbilical vein endothelial cells growing on the membranes; cell number increased as native silk fibroin powder content in the biomedical polyurethane/native silk fibroin powder hybrid membrane was increased from 0% to 50%, and cell morphology changed from spindle-shaped to cobblestone-like as the native silk fibroin powder content was increased from 0% to 70%. The latter change was related to the physical characteristics of the membrane, including hydrophilicity, roughness, and mechanical properties. The in vivo biocompatibility of the native silk fibroin powder-modified biomedical polyurethane membrane was evaluated in a rat model; the histological analysis revealed no systemic toxicity. These results indicate that the biomedical polyurethane/native silk fibroin powder hybrid membrane has superior in vitro and in vivo biocompatibility relative to 100% biomedical polyurethane membranes and thus has potential applications in the fabrication of small-diameter vascular grafts and in tissue engineering.

Reinforcement of SBR/waste rubber powder vulcanizate with in situ generated zinc dimethacrylate

NASA Astrophysics Data System (ADS)

Wang, X. P.; Cheng, B. K.; Zhang, X.; Jia, D. M.

2016-07-01

Methyl acrylic acid/zinc oxide (MAA/ZnO) was introduced to modify styrene- butadiene rubber/waste rubber powder (SBR/WRP) composites by blending. The enhanced mechanical properties and processing ability were presumably originated from improved compatibility and interfacial interaction between WRP and the SBR matrix by the in situ polymerization of zinc dimethacrylate (ZDMA). A refined interface of the modified SBR/WRP composite was observed by scanning electron microscopy. The formation of ZDMA significantly increased the ionic bond content in the vulcanizate, resulting in exceptional mechanical performance. The comprehensive mechanical properties including tensile strength, tear strength and dynamic heat-building performance reached optimum values with 16 phr MAA.

3D printed porous polycaprolactone/oyster shell powder (PCL/OSP) scaffolds for bone tissue engineering

NASA Astrophysics Data System (ADS)

Luo, Wenfeng; Zhang, Shuangying; Lan, Yuewei; Huang, Chen; Wang, Chao; Lai, Xuexu; Chen, Hanwei; Ao, Ningjian

2018-04-01

In this work, oyster shell powder (OSP) was used as the bio-filler and combined with polycaprolactone (PCL) through melt blending methodology. The PCL and PCL/OSP scaffolds were prepared using additive manufacturing process. All the 3D printed scaffolds hold a highly porosity and interconnected pore structures. OSP particles are dispersed in the polymer matrix, which helped to improve the degree of crystallinity and mineralization ability of the scaffolds. There was no significant cytotoxicity of the prepared scaffolds towards MG-63 cells, and all the scaffolds showed a well ALP activity. Therefore, PCL/OSP scaffolds had a high potential to be employed in the bone tissue engineering.

A comparison of mango seed kernel powder, mango leaf powder and Manilkara zapota seed powder for decolorization of methylene blue dye and antimicrobial activity.

PubMed

Sundararaman, B; Muthuramu, K L

2016-11-01

The waste mango seed generated from mango pulp industry in India is a major problem in handling the waste and hence, conversion of mango seed kernel. Mango seeds were collected and processed for oil extraction. Decolorization of methylene blue was achieved by mango seed kernel powder, mango leaf powder and Manilkara zapota seed powder. Higher efficiency was attained in mango seed kernel powder when compared to mango leaf powder and Manilkara zapota seed powder. A 60 to 95 % of removal efficiency was achieved by varying concentration. Effect of pH, dye concentration, adsorbent dosage and temperature were studied. Mango seed kernel powder is a better option that can be used as an adsorbent for the removal of methylene blue and basic red dye from its aqueous solutions.

Engineering Nanostructures by Decorating Magnetic Nanoparticles onto Graphene Oxide Sheets to Shield Electromagnetic Radiations.

PubMed

Mural, Prasanna Kumar S; Pawar, Shital Patangrao; Jayanthi, Swetha; Madras, Giridhar; Sood, Ajay K; Bose, Suryasarathi

2015-08-05

In this study, a minimum reflection loss of -70 dB was achieved for a 6 mm thick shield (at 17.1 GHz frequency) employing a unique approach. This was accomplished by engineering nanostructures through decoration of magnetic nanoparticles (nickel, Ni) onto graphene oxide (GO) sheets. Enhanced electromagnetic (EM) shielding was derived by selectively localizing the nanoscopic particles in a specific phase of polyethylene (PE)/poly(ethylene oxide) (PEO) blends. By introduction of a conducting inclusion (like multiwall carbon nanotubes, MWNTs) together with the engineered nanostructures (nickel-decorated GO, GO-Ni), the shielding efficiency can be enhanced significantly in contrast to physically mixing the particles in the blends. For instance, the composites showed a shielding efficiency >25 dB for a combination of MWNTs (3 wt %) and Ni nanoparticles (52 wt %) in PE/PEO blends. However, similar shielding effectiveness could be achieved for a combination of MWNTs (3 wt %) and 10 vol % of GO-Ni where in the effective concentration of Ni was only 19 wt %. The GO-Ni sheets facilitated in an efficient charge transfer as manifested from high electrical conductivity in the blends besides enhancing the permeability in the blends. It is envisioned that GO is simultaneously reduced in the process of synthesizing GO-Ni, and this facilitated in efficient charge transfer between the neighboring CNTs. More interestingly, the blends with MWNTs/GO-Ni attenuated the incoming EM radiation mostly by absorption. This study opens new avenues in designing polyolefin-based lightweight shielding materials by engineering nanostructures for numerous applications.

Efficient and Stable Ternary Organic Solar Cells Based on Two Planar Nonfullerene Acceptors with Tunable Crystallinity and Phase Miscibility.

PubMed

Wang, Jialin; Peng, Jiajun; Liu, Xiaoyu; Liang, Ziqi

2017-06-21

Planar perylene diimides (PDIs), when used as nonfullerene acceptors for organic photovoltaics, are constrained by their large π-aggregation in solid state. To tackle this issue, another planar nonfullerene acceptor 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone)-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2',3'-d']-s-indaceno[1,2-b:5,6-b']dithiophene (ITIC) with weak crystallinity and near-infrared light absorption is introduced into the PTB7-Th:PDI binary blend to fabricate efficient and stable ternary solar cells. We have finely tuned the PDI/ITIC weight ratio to investigate the influences of individual ITIC and PDI on the optical, electronic, and morphological properties of the PTB7-Th:ITIC:PDI ternary blend. Compared to the binary blend, complementary optical absorption is achieved in all ternary blends. More importantly, it is found that ITIC plays a critical role on largely suppressing the PDI aggregates in the PTB7-Th:PDI blend, while PDI aids to form an interpenetrating network morphology to facilitate charge transport in the PTB7-Th:ITIC blend. Consequently, when the PDI/ITIC ratio is 3:7 (w/w), the PTB7-Th:ITIC:PDI based inverted solar cells exhibit the highest power conversion efficiency of 8.64% due to their favorable out-of-plane π-π stacking, finest phase-separation morphology, and highest charge mobility. Remarkably, the optimal cells that are solution-processed in air show the promising efficiency of 7.09%, suggesting good ambient stability of such ternary solar cells.

In situ monitoring of powder blending by non-invasive Raman spectrometry with wide area illumination.

PubMed

Allan, Pamela; Bellamy, Luke J; Nordon, Alison; Littlejohn, David; Andrews, John; Dallin, Paul

2013-03-25

A 785nm diode laser and probe with a 6mm spot size were used to obtain spectra of stationary powders and powders mixing at 50rpm in a high shear convective blender. Two methods of assessing the effect of particle characteristics on the Raman sampling depth for microcrystalline cellulose (Avicel), aspirin or sodium nitrate were compared: (i) the information depth, based on the diminishing Raman signal of TiO(2) in a reference plate as the depth of powder prior to the plate was increased, and (ii) the depth at which a sample became infinitely thick, based on the depth of powder at which the Raman signal of the compound became constant. The particle size, shape, density and/or light absorption capability of the compounds were shown to affect the "information" and "infinitely thick" depths of individual compounds. However, when different sized fractions of aspirin were added to Avicel as the main component, the depth values of aspirin were the same and matched that of the Avicel: 1.7mm for the "information" depth and 3.5mm for the "infinitely thick" depth. This latter value was considered to be the minimum Raman sampling depth when monitoring the addition of aspirin to Avicel in the blender. Mixing profiles for aspirin were obtained non-invasively through the glass wall of the vessel and could be used to assess how the aspirin blended into the main component, identify the end point of the mixing process (which varied with the particle size of the aspirin), and determine the concentration of aspirin in real time. The Raman procedure was compared to two other non-invasive monitoring techniques, near infrared (NIR) spectrometry and broadband acoustic emission spectrometry. The features of the mixing profiles generated by the three techniques were similar for addition of aspirin to Avicel. Although Raman was less sensitive than NIR spectrometry, Raman allowed compound specific mixing profiles to be generated by studying the mixing behaviour of an aspirin-aspartame-Avicel mixture. Copyright © 2013 Elsevier B.V. All rights reserved.

Effects of fire retardants on physical, mechanical, and fire properties of flat-pressed WPCs

Treesearch

Nadir Ayrilmis; Jan T. Benthien; Heiko Thoemen; Robert H. White

2012-01-01

Physical, mechanical, and fire properties of the flat-pressed wood plastic composites (WPCs) incorporated with various fire retardants (10% by weight) at different levels of wood flour (WF) content, 40, 50, or 60 wt%, were investigated. The WPC panels were made from dry-blended WF, polypropylene (PP), and fire retardant (FR) powders with maleic anhydride-grafted PP (2...

Development of a NIR-based blend uniformity method for a drug product containing multiple structurally similar actives by using the quality by design principles.

PubMed

Lin, Yiqing; Li, Weiyong; Xu, Jin; Boulas, Pierre

2015-07-05

The aim of this study is to develop an at-line near infrared (NIR) method for the rapid and simultaneous determination of four structurally similar active pharmaceutical ingredients (APIs) in powder blends intended for the manufacturing of tablets. Two of the four APIs in the formula are present in relatively small amounts, one at 0.95% and the other at 0.57%. Such small amounts in addition to the similarity in structures add significant complexity to the blend uniformity analysis. The NIR method is developed using spectra from six laboratory-created calibration samples augmented by a small set of spectra from a large-scale blending sample. Applying the quality by design (QbD) principles, the calibration design included concentration variations of the four APIs and a main excipient, microcrystalline cellulose. A bench-top FT-NIR instrument was used to acquire the spectra. The obtained NIR spectra were analyzed by applying principal component analysis (PCA) before calibration model development. Score patterns from the PCA were analyzed to reveal relationship between latent variables and concentration variations of the APIs. In calibration model development, both PLS-1 and PLS-2 models were created and evaluated for their effectiveness in predicting API concentrations in the blending samples. The final NIR method shows satisfactory specificity and accuracy. Copyright © 2015 Elsevier B.V. All rights reserved.

Shrinkage simplex-centroid designs for a quadratic mixture model

NASA Astrophysics Data System (ADS)

Hasan, Taha; Ali, Sajid; Ahmed, Munir

2018-03-01

A simplex-centroid design for q mixture components comprises of all possible subsets of the q components, present in equal proportions. The design does not contain full mixture blends except the overall centroid. In real-life situations, all mixture blends comprise of at least a minimum proportion of each component. Here, we introduce simplex-centroid designs which contain complete blends but with some loss in D-efficiency and stability in G-efficiency. We call such designs as shrinkage simplex-centroid designs. Furthermore, we use the proposed designs to generate component-amount designs by their projection.

Comparative analysis of the Performance and Emission Characteristics of ethanol-butanol-gasoline blends

NASA Astrophysics Data System (ADS)

Taneja, Sumit; Singh, Perminderjit, Dr; Singh, Gurtej

2018-02-01

Global warming and energy security being the global problems have shifted the focus of researchers on the renewable sources of energy which could replace petroleum products partially or as a whole. Ethanol and butanol are renewable sources of energy which can be produced through fermentation of biomass. A lot of research has already been done to develop suitable ethanol-gasoline blends. In contrast very little literature available on the butanol-gasoline blends. This research focuses on the comparison of ethanol-gasoline fuels with butanol-gasoline fuels with regard to the emission and performance in an SI engine. Experiments were conducted on a variable compression ratio SI engine at 1600 rpm and compression ratio 8. The experiments involved the measurement of carbon monoxide, carbon dioxide, oxides of nitrogen and unburned hydrocarbons emission and among performance parameters brake specific fuel consumption and brake thermal efficiency were recorded at three loads of 2.5kgs (25%), 5kgs (50%) and 7.5kgs (75%). Results show that ethanol and butanol content in gasoline have decreased brake specific fuel consumption, carbon monoxide and unburned hydrocarbon emissions while the brake thermal efficiency and oxides of nitrogen are increased. Results indicate thatbutanol-gasoline blends have improved brake specific fuel consumption, carbon monoxide emissions in an SI engine as compared to ethanol-gasoline blends. The carbon dioxide emissions and brake thermal efficiencies are comparable for ethanol-gasoline blends and butanol-gasoline blends. The butanol content has a more adverse effect on emissions of oxides of nitrogen than ethanol.

Anaerobic biodegradation of soybean biodiesel and diesel blends under methanogenic conditions.

PubMed

Wu, Shuyun; Yassine, Mohamad H; Suidan, Makram T; Venosa, Albert D

2015-12-15

Biotransformation of soybean biodiesel and the inhibitory effect of petrodiesel were studied under methanogenic conditions. Biodiesel removal efficiency of more than 95% was achieved in a chemostat with influent biodiesel concentrations up to 2.45 g/L. The kinetics of anaerobic biodegradation of soybean biodiesel B100 (biodiesel only) with different petrodiesel loads was studied using biomass pre-acclimated to B100 and B80 (80% biodiesel and 20% petrodiesel). The results indicated that the biodiesel fraction of the blend could be effectively biodegraded, whereas petrodiesel was not biodegraded at all under methanogenic conditions. The presence of petrodiesel in blends with biodiesel had a greater inhibitory effect on the rate of biodegradation than the biodegradation efficiency (defined as the efficiency of methane production). Both the biodegradation rate coefficient and the methane production efficiency increased almost linearly with the increasing fraction of biodiesel. With the increasing fraction of petrodiesel, the biodegradation rate and efficiency were correlated with the concentration of soluble FAMEs in the water. Copyright © 2015 Elsevier Ltd. All rights reserved.

Impact of Introduction of Blended Learning in Gross Anatomy on Student Outcomes

ERIC Educational Resources Information Center

Green, Rodney A.; Whitburn, Laura Y.

2016-01-01

Blended learning has become increasingly common, in a variety of disciplines, to take advantage of new technology and potentially increase the efficiency and flexibility of delivery. This study aimed to describe blended delivery of a gross anatomy course and to evaluate the effectiveness of the delivery in terms of student outcomes. A gross…

The Role of Leadership in Starting and Operating Blended Learning Charter Schools: A Multisite Case Study

ERIC Educational Resources Information Center

Agostini, Michael Eric

2013-01-01

Heavily utilizing both instructional technology and face-to-face instruction within a bricks-and-mortar school environment, blended learning charter schools are gaining attention as a cost-effective school design. As educators turn to these blended learning school models to improve both the operational efficiency and student outcomes of America's…

A Study Module in the Logical Structure of Cognitive Process in the Context of Variable-Based Blended Learning

ERIC Educational Resources Information Center

Smirnova, Galina I.; Katashev, Valery G.

2017-01-01

Blended learning is increasingly gaining importance in all levels of educational system, particularly in tertiary education. In engineering profiles the core blended learning activity is students' independent work, the efficiency of which is defined by the degree of students' active involvement into the educational process, their ability to absorb…

Effect of powder compaction on radiation-thermal synthesis of lithium-titanium ferrites

NASA Astrophysics Data System (ADS)

Surzhikov, A. P.; Lysenko, E. N.; Vlasov, V. A.; Malyshev, A. V.; Korobeynikov, M. V.; Mikhailenko, M. A.

2017-01-01

Effect of powder compaction on the efficiency of thermal and radiation-thermal synthesis of lithium-substituted ferrites was investigated by X-Ray diffraction and specific magnetization analysis. It was shown that the radiation-thermal heating of compacted powder reagents mixture leads to an increase in efficiency of lithium-titanium ferrites synthesis.

Modulation of active pharmaceutical material release from a novel 'tablet in capsule system' containing an effervescent blend.

PubMed

Gohel, Mukesh C; Sumitra G, Manhapra

2002-02-19

The objective of the present study was to obtain programmed drug delivery from hard gelatin capsules containing a hydrophilic plug (HPMC or guar gum). The significance of factors such as type of plug (powder or tablet), plug thickness and the formulation of fill material on the release pattern of diltiazem HCl, a model drug, was investigated. The body portion of the hard gelatin capsules was cross-linked by the combined effect of formaldehyde and heat treatment. A linear relationship was observed between weight of HPMC K15M and log % drug released at 4 h from the capsules containing the plug in powder form. In order to accelerate the drug release after a lag time of 4 h, addition of an effervescent blend, NaHCO(3) and citric acid, in the capsules was found to be essential. The plugs of HPMC in tablet form, with or without a water soluble adjuvant (NaCl or lactose) were used for obtaining immediate drug release after the lag time. Sodium chloride did not cause significant influence on drug release whereas lactose favourably affected the drug release. The capsules containing HPMC K15M tablet plug (200 mg) and 35 mg effervescent blend in body portion of the capsule met the selection criteria of less than 10% drug release in 4 h and immediate drug release thereafter. It is further shown that the drug release was also dependant on the type of swellable hydrophilic agent (HPMC or guar gum) and molecular weight of HPMC (K15M or 20 cPs). The results reveal that programmed drug delivery can be obtained from hard gelatin capsules by systemic formulation approach.

Investigation of using wavelet analysis for classifying pattern of cyclic voltammetry signals

NASA Astrophysics Data System (ADS)

Jityen, Arthit; Juagwon, Teerasak; Jaisuthi, Rawat; Osotchan, Tanakorn

2017-09-01

Wavelet analysis is an excellent technique for data processing analysis based on linear vector algebra since it has an ability to perform local analysis and is able to analyze an unspecific localized area of a large signal. In this work, the wavelet analysis of cyclic waveform was investigated in order to find the distinguishable feature from the cyclic data. The analyzed wavelet coefficients were proposed to be used as selected cyclic feature parameters. The cyclic voltammogram (CV) of different electrodes consisting of carbon nanotube (CNT) and several types of metal phthalocyanine (MPc) including CoPc, FePc, ZnPc and MnPc powders was used as several sets of cyclic data for various types of coffee. The mixture powder was embedded in a hollow Teflon rod and used as working electrodes. Electrochemical response of the fabricated electrodes in Robusta, blend coffee I, blend coffee II, chocolate malt and cocoa at the same concentrations was measured with scanning rate of 0.05V/s from -1.5 to 1.5V respectively to Ag/AgCl electrode for five scanning loops. The CV of blended CNT electrode with some MPc electrodes indicated the ionic interaction which can be the effect of catalytic oxidation of saccharides and/or polyphenol on the sensor surface. The major information of CV response can be extracted by using several mother wavelet families viz. daubechies (dB1 to dB3), coiflets (coiflet1), biorthogonal (Bior1.1) and symlets (sym2) and then the discrimination of these wavelet coefficients of each data group can be separated by principal component analysis (PCA). The PCA results indicated the clearly separate groups with total contribution more than 62.37% representing from PC1 and PC2.

High-Temperature Metal Matrix Composites

DTIC Science & Technology

1990-06-01

Graduate Student, PhD Candidate Oct 1986 - August 1989. H. Henein: Principal Investigator of Blending Task. Productivity : Papers - J.O.G. Parent, J. Iyengar...the powder metallurgy route provides a better controlled means of forming the product . An overview of the P/M processing route is shown in Figure 1...This approach has its inherent problems. The requirement of a uniform distrihution of the reinforcement material is not always readily achieved. In P/M

Method and composition for molding low density desiccant syntactic foam articles

DOEpatents

Lula, James W.; Schicker, James R.

1984-01-01

A method and a composition are provided for molding low density desiccant syntactic foam articles. A low density molded desiccant article may be made as a syntactic foam by blending a thermosetting resin, microspheres and molecular sieve desiccant powder, molding and curing. Such articles have densities of 0.2-0.9 g/cc, moisture capacities of 1-12% by weight, and can serve as light weight structural supports.

Inhibition of Listeria monocytogenes using natural antimicrobials in no-nitrate-or-nitrite-added ham.

PubMed

Sullivan, Gary A; Jackson-Davis, Armitra L; Niebuhr, Steven E; Xi, Yuan; Schrader, Kohl D; Sebranek, Joseph G; Dickson, James S

2012-06-01

Consumer demand for foods manufactured without the direct addition of chemical preservatives, such as sodium nitrite and organic acid salts, has resulted in a unique class of "naturally" cured meat products. Formulation with a natural nitrate source and nitrate-reducing bacteria results in naturally cured processed meats that possess traits similar to conventionally cured meats. However, previous research has shown that the naturally cured products are more susceptible to pathogen growth. This study evaluated Listeria monocytogenes growth on ham manufactured with natural curing methods and with commercially available clean-label antimicrobials (cultured sugar and vinegar blend; lemon, cherry, and vinegar powder blend) and assessed impacts on physicochemical characteristics of the product. Hams made with either of the antimicrobials supported L. monocytogenes growth similar to that in the traditionally cured control (P > 0.05). Hams made with prefermented celery juice powder had the lowest residual nitrite concentrations (P < 0.05), and when no antimicrobial was added, L. monocytogenes growth was similar to that of the uncured control (P > 0.05). Aside from residual nitrite and nitrate concentrations, few physicochemical differences were identified. These findings show that ham can be produced with natural curing methods and antimicrobials to provide similar L. monocytogenes inhibition and physicochemical traits as in traditionally cured ham.

[Study on the calcium-based sorbent for removal fluorine during coal combustion].

PubMed

Li, Shu-ling; Qi, Qing-jie; Liu, Jian-zhong; Cao, Xin-yu; Zhou, Jun-hu; Cen, Ke-fa

2004-03-01

In the paper, the reaction of CaO-HF and fluorine removal mechanics at high temperature by blending calcium-based sorbents with coal during coal combustion were discussed, and test results about fluorine retention during coal combustion in fluidized bed and chain-grate furnace were reported. The results identified that lime and calcium-based sorbets developed can restratin the emission of fluorine during coal combustion. The efficiency of fluorine removal can reach 66.7%-70.0% at Ca/F 60-70 by blending lime with coal in fluidized bed combustion, and the efficiency of fluorine removal are between 57.32% and 75.19% by blending calcium-based sorbets with coal in chain-grate furnace combustion. Blending CaO or lime with coal during coal combustion can remove SO2 and HF simultaneously.

Floating matrix tablets based on low density foam powder: effects of formulation and processing parameters on drug release.

PubMed

Streubel, A; Siepmann, J; Bodmeier, R

2003-01-01

The aim of this study was to develop and physicochemically characterize single unit, floating controlled drug delivery systems consisting of (i). polypropylene foam powder, (ii). matrix-forming polymer(s), (iii). drug, and (iv). filler (optional). The highly porous foam powder provided low density and, thus, excellent in vitro floating behavior of the tablets. All foam powder-containing tablets remained floating for at least 8 h in 0.1 N HCl at 37 degrees C. Different types of matrix-forming polymers were studied: hydroxypropyl methylcellulose (HPMC), polyacrylates, sodium alginate, corn starch, carrageenan, gum guar and gum arabic. The tablets eroded upon contact with the release medium, and the relative importance of drug diffusion, polymer swelling and tablet erosion for the resulting release patterns varied significantly with the type of matrix former. The release rate could effectively be modified by varying the "matrix-forming polymer/foam powder" ratio, the initial drug loading, the tablet geometry (radius and height), the type of matrix-forming polymer, the use of polymer blends and the addition of water-soluble or water-insoluble fillers (such as lactose or microcrystalline cellulose). The floating behavior of the low density drug delivery systems could successfully be combined with accurate control of the drug release patterns.

[The effect of composition and structure of radiological equivalent materials on radiological equivalent].

PubMed

Wang, Y; Lin, D; Fu, T

1997-03-01

Morphology of inorganic material powders before and after being treated by ultrafine crush was observed by transformite electron microscope. The length and diameter of granules were measured. Polymers inorganic material powders before and after being treated by ultrafine crush were used for preparing radiological equivalent materials. Blending compatibility of inorganic meterials with polymer materials was observed by scanning electron microscope. CT values of tissue equivalent materials were measured by X-ray CT. Distribution of inorganic materials was examined. The compactness of materials was determined by the water absorbed method. The elastic module of materials was measured by laser speckle interferementry method. The results showed that the inorganic material powders treated by the ultrafine crush blent well with polymer and the distribution of these powders in the polymer was homogeneous. The equivalent errors of linear attenuation coefficients and CT values of equivalent materials were small. Their elastic modules increased one order of magnitude from 6.028 x 10(2) kg/cm2 to 9.753 x 10(3) kg/cm2. In addition, the rod inorganic material powders having rod granule blent easily with polymer. The present study provides a theoretical guidance and experimental basis for the design and synthesis of radiological equivalent materials.

Powder metallurgy inspired low-temperature fabrication of high-performance stereocomplexed polylactide products with good optical transparency

PubMed Central

Bai, Dongyu; Liu, Huili; Bai, Hongwei; Zhang, Qin; Fu, Qiang

2016-01-01

Stereocomplexation between enantiomeric poly(l-lactide) (PLLA) and poly(d-lactide) (PDLA) provides an avenue to greatly enhance performance of eco-friendly polylactide (PLA). Unfortunately, although the manufacturing of semicrystalline polymers generally involves melt processing, it is still hugely challenging to create high-performance stereocomplexed polylactide (sc-PLA) products from melt-processed high-molecular-weight PLLA/PDLA blends due to the weak crystallization memory effect of stereocomplex (sc) crystallites after complete melting as well as the substantial degradation of PLA chains at elevated melt-processing temperatures of ca. 240–260 °C. Inspired by the concept of powder metallurgy, here we report a new facile route to address these obstacles by sintering of sc-PLA powder at temperatures as low as 180–210 °C, which is distinctly different from traditional sintering of polymer powders performed at temperatures far exceeding their melting temperatures. The enantiomeric PLA chain segments from adjacent powder particles can interdiffuse across particle interfaces and co-crystallize into new sc crystallites capable of tightly welding the interfaces during the low-temperature sintering process, and thus highly transparent sc-PLA products with outstanding heat resistance, mechanical strength, and hydrolytic stability have been successfully fabricated for the first time. PMID:26837848

Powder metallurgy inspired low-temperature fabrication of high-performance stereocomplexed polylactide products with good optical transparency

NASA Astrophysics Data System (ADS)

Bai, Dongyu; Liu, Huili; Bai, Hongwei; Zhang, Qin; Fu, Qiang

2016-02-01

Stereocomplexation between enantiomeric poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA) provides an avenue to greatly enhance performance of eco-friendly polylactide (PLA). Unfortunately, although the manufacturing of semicrystalline polymers generally involves melt processing, it is still hugely challenging to create high-performance stereocomplexed polylactide (sc-PLA) products from melt-processed high-molecular-weight PLLA/PDLA blends due to the weak crystallization memory effect of stereocomplex (sc) crystallites after complete melting as well as the substantial degradation of PLA chains at elevated melt-processing temperatures of ca. 240-260 °C. Inspired by the concept of powder metallurgy, here we report a new facile route to address these obstacles by sintering of sc-PLA powder at temperatures as low as 180-210 °C, which is distinctly different from traditional sintering of polymer powders performed at temperatures far exceeding their melting temperatures. The enantiomeric PLA chain segments from adjacent powder particles can interdiffuse across particle interfaces and co-crystallize into new sc crystallites capable of tightly welding the interfaces during the low-temperature sintering process, and thus highly transparent sc-PLA products with outstanding heat resistance, mechanical strength, and hydrolytic stability have been successfully fabricated for the first time.

Powder metallurgy inspired low-temperature fabrication of high-performance stereocomplexed polylactide products with good optical transparency.

PubMed

Bai, Dongyu; Liu, Huili; Bai, Hongwei; Zhang, Qin; Fu, Qiang

2016-02-03

Stereocomplexation between enantiomeric poly(l-lactide) (PLLA) and poly(d-lactide) (PDLA) provides an avenue to greatly enhance performance of eco-friendly polylactide (PLA). Unfortunately, although the manufacturing of semicrystalline polymers generally involves melt processing, it is still hugely challenging to create high-performance stereocomplexed polylactide (sc-PLA) products from melt-processed high-molecular-weight PLLA/PDLA blends due to the weak crystallization memory effect of stereocomplex (sc) crystallites after complete melting as well as the substantial degradation of PLA chains at elevated melt-processing temperatures of ca. 240-260 °C. Inspired by the concept of powder metallurgy, here we report a new facile route to address these obstacles by sintering of sc-PLA powder at temperatures as low as 180-210 °C, which is distinctly different from traditional sintering of polymer powders performed at temperatures far exceeding their melting temperatures. The enantiomeric PLA chain segments from adjacent powder particles can interdiffuse across particle interfaces and co-crystallize into new sc crystallites capable of tightly welding the interfaces during the low-temperature sintering process, and thus highly transparent sc-PLA products with outstanding heat resistance, mechanical strength, and hydrolytic stability have been successfully fabricated for the first time.

The chemical bonds effect of anthocyanin and chlorophyll dyes on TiO2 for dye-sensitized solar cell (DSSC)

NASA Astrophysics Data System (ADS)

Ahliha, A. H.; Nurosyid, F.; Supriyanto, A.; Kusumaningsih, T.

2017-11-01

Anthocyanin and chlorophyll dyes have been blended as the photosensitizer of Dye-Sensitized Solar Cell (DSSC). The results study showed the effect of chemical bond dyes on TiO2 and the efficiency of DSSC. Ratio blend of the anthocyanin and chlorophyll dyes are 1:1. The absorbance of dyes and TiO2 were characterized using UV-Vis Spectrophotometer. The chemical bonds contained in TiO2-dyes were characterized using FT-IR spectrophotometer. The efficiency of DSSC was calculated using I-V meter. The absorption spectra of chlorophyll: anthocyanin blend dye solutions and TiO2 films can increase after the dye adsorption. Absorbance characterization of anthocyanin and chlorophyll dye blend solutions showed three peaks at the wavelength of 412 nm; 535.5 nm; and 656.5 nm. Absorbance characterization of spinach before being blend with anthocyanin dyes solutions showed two peaks at the wavelength of 431 nm and 665.5 nm. The absorption spectra of TiO2 films can increase after the dyes adsorption at the wavelength of 400 nm. FT-IR spectra of TiO2 founded the functional groups C-Br, C=C, and O-H. The functional groups founded in anthocyanin: chlorophyll dye blended on the surface of TiO2 are C-Br, C-O, O-H, C-H, C=C, C=O, and O-H. The result showed that the greatest efficiency of 0.0544% at dye red cabbage-spinach. Adsorption blends of anthocyanin and chlorophyll dyes on the surface of TiO2 can be used as the photosensitizer for DSSC.

Development of Biodegradable Polycation-Based Inhalable Dry Gene Powders by Spray Freeze Drying

PubMed Central

Okuda, Tomoyuki; Suzuki, Yumiko; Kobayashi, Yuko; Ishii, Takehiko; Uchida, Satoshi; Itaka, Keiji; Kataoka, Kazunori; Okamoto, Hirokazu

2015-01-01

In this study, two types of biodegradable polycation (PAsp(DET) homopolymer and PEG-PAsp(DET) copolymer) were applied as vectors for inhalable dry gene powders prepared by spray freeze drying (SFD). The prepared dry gene powders had spherical and porous structures with a 5~10-μm diameter, and the integrity of plasmid DNA could be maintained during powder production. Furthermore, it was clarified that PEG-PAsp(DET)-based dry gene powder could more sufficiently maintain both the physicochemical properties and in vitro gene transfection efficiencies of polyplexes reconstituted after powder production than PAsp(DET)-based dry gene powder. From an in vitro inhalation study using an Andersen cascade impactor, it was demonstrated that the addition of l-leucine could markedly improve the inhalation performance of dry powders prepared by SFD. Following pulmonary delivery to mice, both PAsp(DET)- and PEG-PAsp(DET)-based dry gene powders could achieve higher gene transfection efficiencies in the lungs compared with a chitosan-based dry gene powder previously reported by us. PMID:26343708

Properties investigation of sulfonated poly(ether ether ketone)/polyacrylonitrile acid-base blend membrane for vanadium redox flow battery application.

PubMed

Li, Zhaohua; Dai, Wenjing; Yu, Lihong; Liu, Le; Xi, Jingyu; Qiu, Xinping; Chen, Liquan

2014-11-12

Acid-base blend membrane prepared from sulfonated poly(ether ether ketone) (SPEEK) and polyacrylonitrile (PAN) was detailedly evaluated for vanadium redox flow battery (VRFB) application. SPEEK/PAN blend membrane exhibited dense and homogeneous cross-section morphology as scanning electron microscopy and energy-dispersive X-ray spectroscopy images show. The acid-base interaction of ionic cross-linking and hydrogen bonding between SPEEK and PAN could effectively reduce water uptake, swelling ratio, and vanadium ion permeability, and improve the performance and stability of blend membrane. Because of the good balance of proton conductivity and vanadium ion permeability, blend membrane with 20 wt % PAN (S/PAN-20%) showed higher Coulombic efficiency (96.2% vs 91.1%) and energy efficiency (83.5% vs 78.4%) than Nafion 117 membrane at current density of 80 mA cm(-2) when they were used in VRFB single cell. Besides, S/PAN-20% membrane kept a stable performance during 150 cycles at current density of 80 mA cm(-2) in the cycle life test. Hence the SPEEK/PAN acid-base blend membrane could be used as promising candidate for VRFB application.

Removal of Arsenic (V) from Aqueous Solutions Using Chitosan-Red Scoria and Chitosan-Pumice Blends.

PubMed

Asere, Tsegaye Girma; Mincke, Stein; De Clercq, Jeriffa; Verbeken, Kim; Tessema, Dejene A; Fufa, Fekadu; Stevens, Christian V; Du Laing, Gijs

2017-08-09

In different regions across the globe, elevated arsenic contents in the groundwater constitute a major health problem. In this work, a biopolymer chitosan has been blended with volcanic rocks (red scoria and pumice) for arsenic (V) removal. The effect of three blending ratios of chitosan and volcanic rocks (1:2, 1:5 and 1:10) on arsenic removal has been studied. The optimal blending ratio was 1:5 (chitosan: volcanic rocks) with maximum adsorption capacity of 0.72 mg/g and 0.71 mg/g for chitosan: red scoria (Ch-Rs) and chitosan: pumice (Ch-Pu), respectively. The experimental adsorption data fitted well a Langmuir isotherm ( R ² > 0.99) and followed pseudo-second-order kinetics. The high stability of the materials and their high arsenic (V) removal efficiency (~93%) in a wide pH range (4 to 10) are useful for real field applications. Moreover, the blends could be regenerated using 0.05 M NaOH and used for several cycles without losing their original arsenic removal efficiency. The results of the study demonstrate that chitosan-volcanic rock blends should be further explored as a potential sustainable solution for removal of arsenic (V) from water.

Removal of Arsenic (V) from Aqueous Solutions Using Chitosan–Red Scoria and Chitosan–Pumice Blends

PubMed Central

Asere, Tsegaye Girma; Mincke, Stein; De Clercq, Jeriffa; Verbeken, Kim; Tessema, Dejene A.; Fufa, Fekadu; Stevens, Christian V.; Du Laing, Gijs

2017-01-01

In different regions across the globe, elevated arsenic contents in the groundwater constitute a major health problem. In this work, a biopolymer chitosan has been blended with volcanic rocks (red scoria and pumice) for arsenic (V) removal. The effect of three blending ratios of chitosan and volcanic rocks (1:2, 1:5 and 1:10) on arsenic removal has been studied. The optimal blending ratio was 1:5 (chitosan: volcanic rocks) with maximum adsorption capacity of 0.72 mg/g and 0.71 mg/g for chitosan: red scoria (Ch–Rs) and chitosan: pumice (Ch–Pu), respectively. The experimental adsorption data fitted well a Langmuir isotherm (R2 > 0.99) and followed pseudo-second-order kinetics. The high stability of the materials and their high arsenic (V) removal efficiency (~93%) in a wide pH range (4 to 10) are useful for real field applications. Moreover, the blends could be regenerated using 0.05 M NaOH and used for several cycles without losing their original arsenic removal efficiency. The results of the study demonstrate that chitosan-volcanic rock blends should be further explored as a potential sustainable solution for removal of arsenic (V) from water. PMID:28792443

Polymer Solar Cells with 90% External Quantum Efficiency Featuring an Ideal Light- and Charge-Manipulation Layer.

PubMed

Chen, Jing-De; Li, Yan-Qing; Zhu, Jingshuai; Zhang, Qianqian; Xu, Rui-Peng; Li, Chi; Zhang, Yue-Xing; Huang, Jing-Sheng; Zhan, Xiaowei; You, Wei; Tang, Jian-Xin

2018-03-01

Rapid progress in the power conversion efficiency (PCE) of polymer solar cells (PSEs) is beneficial from the factors that match the irradiated solar spectrum, maximize incident light absorption, and reduce photogenerated charge recombination. To optimize the device efficiency, a nanopatterned ZnO:Al 2 O 3 composite film is presented as an efficient light- and charge-manipulation layer (LCML). The Al 2 O 3 shells on the ZnO nanoparticles offer the passivation effect that allows optimal electron collection by suppressing charge-recombination loss. Both the increased refractive index and the patterned deterministic aperiodic nanostructure in the ZnO:Al 2 O 3 LCML cause broadband light harvesting. Highly efficient single-junction PSCs for different binary blends are obtained with a peak external quantum efficiency of up to 90%, showing certified PCEs of 9.69% and 13.03% for a fullerene blend of PTB7:PC 71 BM and a nonfullerene blend, FTAZ:IDIC, respectively. Because of the substantial increase in efficiency, this method unlocks the full potential of the ZnO:Al 2 O 3 LCML toward future photovoltaic applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The effect of annealing temperature on the properties of powder metallurgy processed Ti-35Nb-2Zr-0.5O alloy.

PubMed

Málek, Jaroslav; Hnilica, František; Veselý, Jaroslav; Smola, Bohumil; Medlín, Rostislav

2017-11-01

Ti-35Nb-2Zr-0.5O (wt%) alloy was prepared via a powder metallurgy process (cold isostatic pressing of blended elemental powders and subsequent sintering) with the primary aim of using it as a material for bio-applications. Sintered specimens were swaged and subsequently the influence of annealing temperature on the mechanical and structural properties was studied. Specimens were annealed at 800, 850, 900, 950, and 1000°C for 0.5h and water quenched. Significant changes in microstructure (i.e. precipitate dissolution or grain coarsening) were observed in relation to increasing annealing temperature. In correlation with those changes, the mechanical properties were also studied. The ultimate tensile strength increased from 925MPa (specimen annealed at 800°C) to 990MPa (900°C). Also the elongation increased from ~ 13% (800°C) to more than 20% (900, 950, and 1000°C). Copyright © 2017 Elsevier Ltd. All rights reserved.

Nonlinear optical imaging for sensitive detection of crystals in bulk amorphous powders.

PubMed

Kestur, Umesh S; Wanapun, Duangporn; Toth, Scott J; Wegiel, Lindsay A; Simpson, Garth J; Taylor, Lynne S

2012-11-01

The primary aim of this study was to evaluate the utility of second-order nonlinear imaging of chiral crystals (SONICC) to quantify crystallinity in drug-polymer blends, including solid dispersions. Second harmonic generation (SHG) can potentially exhibit scaling with crystallinity between linear and quadratic depending on the nature of the source, and thus, it is important to determine the response of pharmaceutical powders. Physical mixtures containing different proportions of crystalline naproxen and hydroxyl propyl methyl cellulose acetate succinate (HPMCAS) were prepared by blending and a dispersion was produced by solvent evaporation. A custom-built SONICC instrument was used to characterize the SHG intensity as a function of the crystalline drug fraction in the various samples. Powder X-ray diffraction (PXRD) and Raman spectroscopy were used as complementary methods known to exhibit linear scaling. SONICC was able to detect crystalline drug even in the presence of 99.9 wt % HPMCAS in the binary mixtures. The calibration curve revealed a linear dynamic range with a R(2) value of 0.99 spanning the range from 0.1 to 100 wt % naproxen with a root mean square error of prediction of 2.7%. Using the calibration curve, the errors in the validation samples were in the range of 5%-10%. Analysis of a 75 wt % HPMCAS-naproxen solid dispersion with SONICC revealed the presence of crystallites at an earlier time point than could be detected with PXRD and Raman spectroscopy. In addition, results from the crystallization kinetics experiment using SONICC were in good agreement with Raman spectroscopy and PXRD. In conclusion, SONICC has been found to be a sensitive technique for detecting low levels (0.1% or lower) of crystallinity, even in the presence of large quantities of a polymer. Copyright © 2012 Wiley-Liss, Inc.

Application of Terahertz Attenuated Total Reflection Spectroscopy to Detect Changes in the Physical Properties of Lactose during the Lubrication Process Required for Drug Formulation.

PubMed

Dohi, Masafumi; Momose, Wataru; Yamashita, Kazunari; Hakomori, Tadashi; Sato, Shusaku; Noguchi, Shuji; Terada, Katsuhide

2017-02-01

Manufacturing the solid dosage form of an orally administered drug requires lubrication to enhance manufacturability, ensuring that critical quality attributes such as disintegration and dissolution of the drug product are maintained during manufacture. Here, to evaluate lubrication performance during manufacture, we used terahertz attenuated total reflection (THz-ATR) spectroscopy to detect differences in the physical characteristics of the lubricated powder. We applied a simple formulation prepared by blending granulated lactose as filler with magnesium stearate as lubricant. A flat tablet was prepared using the lubricated powder to acquire sharp THz-ATR absorption peaks of the samples. First, we investigated the effects of lubricant concentration and compression pressure on preparation of the tablet and then determined the effect of the pressure applied to samples in contact with the ATR prism on sample absorption amplitude. We focused on the differences in the magnitudes of spectra at the lactose-specific frequency. Second, we conducted the dynamic lubrication process using a 120-L mixer to investigate differences in the magnitudes of absorption corresponding to the lactose-specific frequency during lubrication. In both studies, enriching the lubricated powder with a higher concentration of magnesium stearate or prolonging blending time correlated with higher magnitudes of spectra at the lactose-specific frequency. Further, in the dynamic lubrication study, the wettability and disintegration time of the tablets were compared with the absorption spectra amplitudes at the lactose-specific frequency. We conclude that THz-ATR spectroscopy is useful for detecting differences in densities caused by a change in the physical properties of lactose during lubrication.

Quantitative Determination of Fluorine Content in Blends of Polylactide (PLA)–Talc Using Near Infrared Spectroscopy

PubMed Central

Tamburini, Elena; Tagliati, Chiara; Bonato, Tiziano; Costa, Stefania; Scapoli, Chiara; Pedrini, Paola

2016-01-01

Near-infrared spectroscopy (NIRS) has been widely used for quantitative and/or qualitative determination of a wide range of matrices. The objective of this study was to develop a NIRS method for the quantitative determination of fluorine content in polylactide (PLA)-talc blends. A blending profile was obtained by mixing different amounts of PLA granules and talc powder. The calibration model was built correlating wet chemical data (alkali digestion method) and NIR spectra. Using FT (Fourier Transform)-NIR technique, a Partial Least Squares (PLS) regression model was set-up, in a concentration interval of 0 ppm of pure PLA to 800 ppm of pure talc. Fluorine content prediction (R2cal = 0.9498; standard error of calibration, SEC = 34.77; standard error of cross-validation, SECV = 46.94) was then externally validated by means of a further 15 independent samples (R2EX.V = 0.8955; root mean standard error of prediction, RMSEP = 61.08). A positive relationship between an inorganic component as fluorine and NIR signal has been evidenced, and used to obtain quantitative analytical information from the spectra. PMID:27490548

Drawing Sensors with Ball-Milled Blends of Metal-Organic Frameworks and Graphite

PubMed Central

Ko, Michael; Aykanat, Aylin; Smith, Merry K.

2017-01-01

The synthetically tunable properties and intrinsic porosity of conductive metal-organic frameworks (MOFs) make them promising materials for transducing selective interactions with gaseous analytes in an electrically addressable platform. Consequently, conductive MOFs are valuable functional materials with high potential utility in chemical detection. The implementation of these materials, however, is limited by the available methods for device incorporation due to their poor solubility and moderate electrical conductivity. This manuscript describes a straightforward method for the integration of moderately conductive MOFs into chemiresistive sensors by mechanical abrasion. To improve electrical contacts, blends of MOFs with graphite were generated using a solvent-free ball-milling procedure. While most bulk powders of pure conductive MOFs were difficult to integrate into devices directly via mechanical abrasion, the compressed solid-state MOF/graphite blends were easily abraded onto the surface of paper substrates equipped with gold electrodes to generate functional sensors. This method was used to prepare an array of chemiresistors, from four conductive MOFs, capable of detecting and differentiating NH3, H2S and NO at parts-per-million concentrations. PMID:28946624

Evolved phase separation toward balanced charge transport and high efficiency in polymer solar cells.

PubMed

Fan, Haijun; Zhang, Maojie; Guo, Xia; Li, Yongfang; Zhan, Xiaowei

2011-09-01

Understanding effect of morphology on charge carrier transport within polymer/fullerene bulk heterojunction is necessary to develop high-performance polymer solar cells. In this work, we synthesized a new benzodithiophene-based polymer with good self-organization behavior as well as favorable morphology evolution of its blend films with PC(71)BM under improved processing conditions. Charge carrier transport behavior of blend films was characterized by space charge limited current method. Evolved blend film morphology by controlling blend composition and additive content gradually reaches an optimized state, featured with nanoscale fibrilla polymer phase in moderate size and balanced mobility ratio close to 1:1 for hole and electron. This optimized morphology toward more balanced charge carrier transport accounts for the best power conversion efficiency of 3.2%, measured under simulated AM 1.5 solar irradiation 100 mW/cm(2), through enhancing short circuit current and reducing geminate recombination loss.

Computational approach to the study of morphological properties of polymer/fullerene blends in photovoltaics

NASA Astrophysics Data System (ADS)

Gaitho, Francis M.; Mola, Genene T.; Pellicane, Giuseppe

2018-02-01

Organic solar cells have the ability to transform solar energy efficiently and have a promising energy balance. Producing these cells is economical and makes use of methods of printing using inks built on solvents that are well-matched with a variety of cheap materials like flexible plastic or paper. The primary materials used to manufacture organic solar cells include carbon-based semiconductors, which are good light absorbers and efficient charge generators. In this article, we review previous research of interest based on morphology of polymer blends used in bulk heterojunction (BHJ) solar cells and introduce their basic principles. We further review computational models used in the analysis of surface behavior of polymer blends in BHJ as well as the trends in the field of polymer surface science as applied to BHJ photovoltaics. We also give in brief, the opportunities and challenges in the area of polymer blends on BHJ organic solar cells.

A study on emission characteristics of an EFI engine with ethanol blended gasoline fuels

NASA Astrophysics Data System (ADS)

He, Bang-Quan; Wang, Jian-Xin; Hao, Ji-Ming; Yan, Xiao-Guang; Xiao, Jian-Hua

The effect of ethanol blended gasoline fuels on emissions and catalyst conversion efficiencies was investigated in a spark ignition engine with an electronic fuel injection (EFI) system. The addition of ethanol to gasoline fuel enhances the octane number of the blended fuels and changes distillation temperature. Ethanol can decrease engine-out regulated emissions. The fuel containing 30% ethanol by volume can drastically reduce engine-out total hydrocarbon emissions (THC) at operating conditions and engine-out THC, CO and NO x emissions at idle speed, but unburned ethanol and acetaldehyde emissions increase. Pt/Rh based three-way catalysts are effective in reducing acetaldehyde emissions, but the conversion of unburned ethanol is low. Tailpipe emissions of THC, CO and NO x have close relation to engine-out emissions, catalyst conversion efficiency, engine's speed and load, air/fuel equivalence ratio. Moreover, the blended fuels can decrease brake specific energy consumption.

Inhomogeneity of block copolymers at the interface of an immiscible polymer blend

NASA Astrophysics Data System (ADS)

Ryu, Ji Ho; Kim, YongJoo; Lee, Won Bo

2018-04-01

We present the effects of structure and stiffness of block copolymers on the interfacial properties of an immiscible homopolymer blend. Diblock and two-arm grafted copolymers with variation in stiffness are modeled using coarse-grained molecular dynamics to compare the compatibilization efficiency, i.e., reduction of interfacial tension. Overall, grafted copolymers are located more compactly at the interface and show better compatibilization efficiency than diblock copolymers. In addition, an increase in the stiffness for one of the blocks of the diblock copolymers causes unusual inhomogeneous interfacial coverage due to bundle formation. However, an increase in the stiffness for one of blocks of the grafted copolymers prevents the bundle formation due to the branched chain. As a result, homogeneous interfacial coverage of homopolymer blends is realized with significant reduction of interfacial tension which makes grafted copolymer a better candidate for the compatibilizer of immiscible homopolymer blend.

Identifying ingredients that delay outgrowth of Listeria monocytogenes in natural, organic, and clean-label ready-to-eat meat and poultry products.

PubMed

McDonnell, Lindsey M; Glass, Kathleen A; Sindelar, Jeffrey J

2013-08-01

The objective of this study was to identify ingredients that inhibit Listeria monocytogenes in natural, organic, or clean-label ready-to-eat meat and poultry products. Fourteen ingredients were screened in uncured (no-nitrate-or-nitrite-added), traditional-cured (156 ppm of purified sodium nitrite), cultured (alternative cured, natural nitrate source, and Staphylococcus carnosus), or preconverted (alternative cured, natural nitrite source) turkey slurries. Slurries were cooked, cooled, inoculated to yield 3 log CFU/ml L. monocytogenes, stored at 4°C, and tested weekly for 4 weeks. Three antimicrobial ingredients, 1.5 % vinegar-lemon-cherry powder blend, 2.5 % buffered vinegar, and 3.0 % cultured sugar-vinegar blend, were incorporated into alternative-cured ham and uncured roast beef and deli-style turkey breast. Controls included all three meat products without antimicrobial ingredients and a traditional-cured ham with 2.8 % sodium lactate-diacetate. Cooked, sliced products were inoculated with 3 log CFU/g L. monocytogenes, vacuum packed, and stored at 4 or 7°C, for up to 12 weeks. For control products without antimicrobial agents stored at 4°C, a 2-log L. monocytogenes increase was observed at 2 weeks for ham and turkey and at 4 weeks for roast beef. Growth (>1-log increase) in the sodium lactate-diacetate was delayed until week 6. Compared with the control, the addition of either vinegar-lemon-cherry powder blend or buffered vinegar delayed L. monocytogenes growth for an additional 2 weeks, while the addition of cultured sugar-vinegar blend delayed growth for an additional 4 weeks for both ham and turkey. The greatest L. monocytogenes delay was observed in roast beef containing any of the three antimicrobial ingredients, with no growth detected through 12 weeks at 4°C for all the treatments. As expected, L. monocytogenes grew substantially faster in products stored at 7°C than at 4°C. These data suggest that antimicrobial ingredients from a natural source can enhance the safety of ready-to-eat meat and poultry products, but their efficacy is improved in products containing nitrite and with lower moisture and pH.

Identification of mothball powder composition by float tests and melting point tests.

PubMed

Tang, Ka Yuen

2018-07-01

The aim of the study was to identify the composition, as either camphor, naphthalene, or paradichlorobenzene, of mothballs in the form of powder or tiny fragments by float tests and melting point tests. Naphthalene, paradichlorobenzene and camphor mothballs were blended into powder and tiny fragments (with sizes <1/10 of the size of an intact mothball). In the float tests, the mothball powder and tiny fragments were placed in water, saturated salt solution and 50% dextrose solution (D50), and the extent to which they floated or sank in the liquids was observed. In the melting point tests, the mothball powder and tiny fragments were placed in hot water with a temperature between 53 and 80 °C, and the extent to which they melted was observed. Both the float and melting point tests were then repeated using intact mothballs. Three emergency physicians blinded to the identities of samples and solutions visually evaluated each sample. In the float tests, paradichlorobenzene powder partially floated and partially sank in all three liquids, while naphthalene powder partially floated and partially sank in water. Naphthalene powder did not sink in D50 or saturated salt solution. Camphor powder floated in all three liquids. Float tests identified the compositions of intact mothball accurately. In the melting point tests, paradichlorobenzene powder melted completely in hot water within 1 min while naphthalene powder and camphor powder did not melt. The melted portions of paradichlorobenzene mothballs were sometimes too small to be observed in 1 min but the mothballs either partially or completely melted in 5 min. Both camphor and naphthalene intact mothballs did not melt in hot water. For mothball powder, the melting point tests were more accurate than the float tests in differentiating between paradichlorobenzene and non-paradichlorobenzene (naphthalene or camphor). For intact mothballs, float tests performed better than melting point tests. Float tests can identify camphor mothballs but melting point tests cannot. We suggest melting point tests for identifying mothball powder and tiny fragments while float tests are recommended for intact mothball and large fragments.

Suberin Fatty Acids from Outer Birch Bark: Isolation and Physical Material Characterization.

PubMed

Heinämäki, Jyrki; Pirttimaa, Minni M; Alakurtti, Sami; Pitkänen, H Pauliina; Kanerva, Heimo; Hulkko, Janne; Paaver, Urve; Aruväli, Jaan; Yliruusi, Jouko; Kogermann, Karin

2017-04-28

The isolation and physical material properties of suberin fatty acids (SFAs) were investigated with special reference to their potential applications as novel pharmaceutical excipients. SFAs were isolated from outer birch bark (OBB) with a new extractive hydrolysis method. The present simplified isolation process resulted in a moderate batch yield and chemical purity of SFAs, but further development is needed for establishing batch-to-batch variation. Cryogenic milling was the method of choice for the particle size reduction of SFAs powder. The cryogenically milled SFAs powder exhibited a semicrystalline structure with apparent microcrystalline domains within an amorphous fatty acids matrix. The thermogravimetric analysis (TGA) of SFAs samples showed a good thermal stability up to 200 °C, followed by a progressive weight loss, reaching a plateau at about 95% volatilization at about 470 °C. The binary blends of SFAs and microcrystalline cellulose (MCC; Avicel PH 101) in a ratio of 25:75 (w/w) displayed good powder flow and tablet compression properties. The corresponding theophylline-containing tablets showed sustained or prolonged-release characteristics. The physicochemical and bulk powder properties of SFAs isolated from OBB are auspicious in terms of potential pharmaceutical excipient applications.

Efficiency of solution-processed multilayer polymer light-emitting diodes using charge blocking layers

NASA Astrophysics Data System (ADS)

Kasparek, Christian; Rörich, Irina; Blom, Paul W. M.; Wetzelaer, Gert-Jan A. H.

2018-01-01

By blending semiconducting polymers with the cross-linkable matrix ethoxylated-(4)-bisphenol-a-dimethacrylate (SR540), an insoluble layer is acquired after UV-illumination. Following this approach, a trilayer polymer light-emitting diode (PLED) consisting of a blend of poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine] (poly-TPD) and SR540 as an electron-blocking layer, Super Yellow-Poly(p-phenylene vinylene) (SY-PPV) blended with SR540 as an emissive layer, and poly(9,9-di-n-octylfluorenyl-2,7-diyl) as a hole-blocking layer is fabricated from solution. The trilayer PLED shows a 23% increase in efficiency at low voltage as compared to a single layer SY-PPV PLED. However, at higher voltage, the advantage in current efficiency gradually decreases. A combined experimental and modelling study shows that the increased efficiency is not only due to the elimination of exciton quenching at the electrodes but also due to suppressed nonradiative trap-assisted recombination due to carrier confinement. At high voltages, holes can overcome the hole-blocking barrier, which explains the efficiency roll-off.

Highly efficient single-layer dendrimer light-emitting diodes with balanced charge transport

NASA Astrophysics Data System (ADS)

Anthopoulos, Thomas D.; Markham, Jonathan P. J.; Namdas, Ebinazar B.; Samuel, Ifor D. W.; Lo, Shih-Chun; Burn, Paul L.

2003-06-01

High-efficiency single-layer-solution-processed green light-emitting diodes based on a phosphorescent dendrimer are demonstrated. A peak external quantum efficiency of 10.4% (35 cd/A) was measured for a first generation fac-tris(2-phenylpyridine) iridium cored dendrimer when blended with 4,4'-bis(N-carbazolyl)biphenyl and electron transporting 1,3,5-tris(2-N-phenylbenzimidazolyl)benzene at 8.1 V. A maximum power efficiency of 12.8 lm/W was measured also at 8.1 V and 550 cd/m2. These results indicate that, by simple blending of bipolar and electron-transporting molecules, highly efficient light-emitting diodes can be made employing a very simple device structure.

Biopolymer-prebiotic carbohydrate blends and their effects on the retention of bioactive compounds and maintenance of antioxidant activity.

PubMed

Silva, Eric Keven; Zabot, Giovani L; Cazarin, Cinthia B B; Maróstica, Mário R; Meireles, M Angela A

2016-06-25

The objective of this study was to evaluate the use of inulin (IN), a prebiotic carbohydrate without superficial activity, as an encapsulating matrix of lipophilic bioactive compounds. For achieving the encapsulation, IN was associated with biopolymers that present superficial activity: modified starch (HiCap), whey protein isolate (WPI) and gum acacia (GA). Encapsulation was performed through emulsification assisted by ultrasound followed by freeze-drying (FD) process to dry the emulsions. All blends retained geranylgeraniol. GA-IN blend yielded the highest geranylgeraniol retention (96±2wt.%) and entrapment efficiency (94±3wt.%), whilst WPI-IN blend yielded the highest encapsulation efficiency (88±2wt.%). After encapsulation, composition of geranylgeraniol in the annatto seed oil was maintained (23.0±0.5g/100g of oil). Such findings indicate that the method of encapsulation preserved the active compound. All blends were also effective for maintaining the antioxidant activity of the oil through ORAC and DPPH analyses. Copyright © 2016 Elsevier Ltd. All rights reserved.

Phase equilibria in polymer blend thin films: A Hamiltonian approach

NASA Astrophysics Data System (ADS)

Souche, M.; Clarke, N.

2009-12-01

We propose a Hamiltonian formulation of the Flory-Huggins-de Gennes theory describing a polymer blend thin film. We then focus on the case of 50:50 polymer blends confined between antisymmetric walls. The different phases of the system and the transitions between them, including finite-size effects, are systematically studied through their relation with the geometry of the Hamiltonian flow in phase space. This method provides an easy and efficient way, with strong graphical insight, to infer the qualitative physical behavior of polymer blend thin films.

Fatigue Performance of Powder Metallurgy (PM) Ti-6Al-4V Alloy: A Critical Analysis of Current Fatigue Data and Metallurgical Approaches for Improving Fatigue Strength

NASA Astrophysics Data System (ADS)

Cao, Fei; Ravi Chandran, K. S.

2016-03-01

A comprehensive assessment of fatigue performance of powder metallurgy (PM) Ti-6Al-4V alloy, manufactured using various powder-based processing approaches to-date, is performed in this work. The focus is on PM processes that use either blended element (BE) or pre-alloyed (PA) powder as feedstock. Porosity and the microstructure condition have been found to be the two most dominant material variables that control the fatigue strength. The evaluation reveals that the fatigue performance of PM Ti-6Al-4V, in the as-sintered state, is far lower than that in the wrought condition. This is largely caused by residual porosity, even if it is present in small amounts, or, by the coarse lamellar colony microstructure. The fatigue strength is significantly improved by the closure of pores, and it approaches the levels of wrought Ti-6Al-4V alloys, after hot-isostatic-pressing (HIPing). Further thermo-mechanical and heat treatments lead to additional increases in fatigue strength-in one case, a high fatigue strength level, exceeding that of the mill-annealed condition, was achieved. The work identifies the powder, process and microstructure improvements that are necessary for achieving high fatigue strength in powder metallurgical Ti-6Al-4V alloys in order for them to effectively compete with wrought forms. The present findings, gathered from the traditional titanium powder metallurgy, are also directly applicable to additively manufactured titanium, because of the similarities in pores, defects, and microstructures between the two manufacturing processes.

Investigation of drug-excipient compatibility using rheological and thermal tools

NASA Astrophysics Data System (ADS)

Trivedi, Maitri R.

HYPOTHESIS: We plan to investigate a different approach to evaluate drug-excipient physical compatibility using rheological and thermal tools as opposed to commonly used chemical techniques in pharmaceutical industry. This approach offers practical solutions to routinely associated problems arising with API's and commonly used hydrates forms of excipients. ABSTRACT: Drug-Excipient compatibility studies are an important aspect of pre-formulation and formulation development in pharmaceutical research and development. Various approaches have been used in pharmaceutical industry including use of thermal analysis and quantitative assessment of drug-excipient mixtures after keeping the samples under stress environment depending upon the type of formulation. In an attempt to provide better understanding of such compatibility aspect of excipients with different properties of API, various rheological and thermal studies were conducted on binary mixtures of excipients which exist in different hydrates. Dibasic Calcium Phosphate (DCP, anhydrous and dihydrate forms) and Lactose (Lac, anhydrous and monohydrate) were selected with cohesive API's (Acetaminophen and Aspirin). Binary mixtures of DCP and Lac were prepared by addition of 0% w/w to 50% w/w of the API into each powder blend. Rheological and thermal aspects were considered using different approaches such as powder rheometer, rotational shear cell and traditional rheometery approaches like angle of repose (AOR), hausner's ratio (HR) and cares index (CI). Thermal analysis was conducted using modulated differential scanning calorimetry (MDSC) and thermal effusivity. The data suggested that the powder rheometer showed distinctive understanding in the flowability behavior of binary mixtures with addition of increasing proportion of API's than traditional approaches. Thermal approaches revealed the potential interaction of water of crystallization DCP-D with the API (APAP) while such interactions were absent in DCP-A, while in case of Lac-M and Lac-A, interaction with water of crystallization were not present. Binary mixtures prepared with DCP-D were better flowable while blends with DCP-A were better in stability (physical), compressibility and permeability. Similarly binary mixtures prepared with Lac-M were better flowable and stable in physical compatibility as compared to Lac-A. Lac-A were better in compressibility and permeability. Second part of these research included understanding the powder behavior from wet granulation point of view. Wet granulation includes the formation of agglomerates with powders to form granules in order to have better flowability, content uniformity and compressibility of granular mass. End point determination of powders involving change in powder energies and compressibility, permeability along with thermal analyses were conducted. The effects of water of crystallization on end point determination was studied and based on which overall effects on drug-excipient compatibility using different hydrate forms of excipients were evaluated.

Decoration of multi-walled carbon nanotubes by polymer wrapping and its application in MWCNT/polyethylene composites.

PubMed

Hsiao, An-En; Tsai, Shu-Ya; Hsu, Mei-Wen; Chang, Shinn-Jen

2012-05-06

We dispersed the non-covalent functionalization of multi-walled carbon nanotubes (CNTs) with a polymer dispersant and obtained a powder of polymer-wrapped CNTs. The UV-vis absorption spectrum was used to investigate the optimal weight ratio of the CNTs and polymer dispersant. The powder of polymer-wrapped CNTs had improved the drawbacks of CNTs of being lightweight and difficult to process, and it can re-disperse in a solvent. Then, we blended the polymer-wrapped CNTs and polyethylene (PE) by melt-mixing and produced a conductive masterbatch and CNT/PE composites. The polymer-wrapped CNTs showed lower surface resistivity in composites than the raw CNTs. The scanning electron microscopy images also showed that the polymer-wrapped CNTs can disperse well in composites than the raw CNTs.

Commercialization of NASA PS304 Solid Lubricant Coating Enhanced by Fundamental Powder Flow Research

NASA Technical Reports Server (NTRS)

Stanford, Malcolm K.

2003-01-01

The NASA Glenn Research Center has developed a patented high-temperature solid lubricant coating, designated PS304, for reducing friction and wear in bearing systems. The material used to produce the coating is initially a blend of metallic and ceramic powders that are deposited on the bearing surface by the plasma spray process. PS304 was developed to lubricate foil air bearings in Oil-Free turbomachinery, where the moving surfaces are coated with a hydrodynamic air film except at the beginning and end of an operation cycle when the air film is not present. The coating has been successful in several applications including turbochargers, land-based turbines, and industrial drying furnace conveyor components, with current development activities directed at implementation in Oil-Free aeropropulsion engines.

Magnetomechanical properties of composites and fibers made from thermoplastic elastomers (TPE) and carbonyl iron powder (CIP)

NASA Astrophysics Data System (ADS)

Schrödner, Mario; Pflug, Günther

2018-05-01

Magnetoactive elastomers (MAE) made from composites of five thermoplastic elastomers (TPE) of different stiffness with carbonyl iron powder (CIP) as magnetic component were investigated. The composites were produced by melt blending of the magnetic particles with the TPEs in a twin-screw extruder. The resulting materials were characterized by ac permeability testing, stress-strain measurements with and without external magnetic field and magnetically controlled bending of long cylindrical rods in a homogenous magnetic field. The magnetic field necessary for deflection of the rods decreases with decreasing modulus and increasing iron particle content. This effect can be used e.g. for magnetically controlled actuation. Some highly filled MAE show a magnetic field induced increase of Young's modulus. Filaments could be spun from some of the composites.

Insight Into the Role of PC71BM on Enhancing the Photovoltaic Performance of Ternary Organic Solar Cells.

PubMed

Wang, Bei; Fu, Yingying; Yan, Chi; Zhang, Rui; Yang, Qingqing; Han, Yanchun; Xie, Zhiyuan

2018-01-01

The development of non-fullerene acceptor molecules have remarkably boosted power conversion efficiency (PCE) of polymer solar cells (PSCs) due to the improved spectral coverage and reduced energy loss. An introduction of fullerene molecules into the non-fullerene acceptor-based blend may further improve the photovoltaic performance of the resultant ternary PSCs. However, the underlying mechanism is still debatable. Herein, the ternary PSCs based on PBDB-T:ITIC:PC 71 BM blend were fabricated and its PCE was increased to 10.2% compared to 9.2% for the binary PBDB-T:ITIC devices and 8.1% for the PBDB-T:PC 71 BM PSCs. Systematic investigation was carried out to disclose the effect of PC 71 BM on the blend morphology and charge transport behavior. It is found that the PC 71 BM tends to intermix with the PBDB-T donor compared to the ITIC counterpart. A small amount of PC 71 BM in the ternary blend is helpful for ITIC to aggregate and form efficient electron-transport pathways. Accordingly, the electron mobility is increased and the density of electron traps is decreased in the ternary blend in comparison with the PBDB-T:ITIC blend. Finally, the suppressed bimolecular recombination and enhanced charge collection lead to high PCE for the ternary solar cells.

High-temperature electrically conductive ceramic composite and method for making same

DOEpatents

Beck, David E.; Gooch, Jack G.; Holcombe, Jr., Cressie E.; Masters, David R.

1983-01-01

The present invention relates to a metal-oxide ceramic composition useful in induction heating applications for treating uranium and uranium alloys. The ceramic composition is electrically conductive at room temperature and is nonreactive with molten uranium. The composition is prepared from a particulate admixture of 20 to 50 vol. % niobium and zirconium oxide which may be stabilized with an addition of a further oxide such as magnesium oxide, calcium oxide, or yttria. The composition is prepared by blending the powders, pressing or casting the blend into the desired product configuration, and then sintering the casting or compact in an inert atmosphere. In the casting operation, calcium aluminate is preferably added to the admixture in place of a like quantity of zirconia for providing a cement to help maintain the integrity of the sintered product.

Eco-friendly Fibre from Recycled Polypropylene of Bottle Cap Waste and Lignin

NASA Astrophysics Data System (ADS)

Soekoco, A. S.; Basuki, A.; Mardiyati

2016-01-01

Ecofriendly fibre is one of potential alternatives to fulfill the rising demand in textile material supply which is limited due to the decreasing reserve of oil. Large amount of polypropylene waste from bottle cap and lignin as a byproduct from pulp industry are potential solutions. Grinded polypropylene bottle cap was blended with lignin powder in concentration of 5 wt. % processed by melt spinning at 170° C temperature. The fibres produced have an average diameter 170 and 250 micrometres. In view of the mechanical properties. the tensile strength is 11.9 MPa for fibre with 170 micrometres diameter and 14.7 MPa for fibre with 250 micrometres diameter. Fibre surface morphology was further studied using micron microscope. and the result shows black flocks spread in the fibre. indicating that the lignin does not blend evenly.

Fortification of Wheat Bread with 3-7% Defatted Soy Flour Improves Formulation, Organoleptic Characteristics, and Rat Growth Rate

PubMed Central

Mahmoodi, Mohammad Reza; Mashayekh, Morteza; Entezari, Mohammad Hasan

2014-01-01

Background: The present study designed to test effects of defatted soy-fortified wheat bread on the organoleptic properties as well as influences on rat growth rate. Methods: Defatted soy flour (DSF) was blended with wheat flour with extraction rate of 82-84% at 3, 7, and 7% levels plus 3% sugar. Bread produced with these blends compared with regular Taftoon bread and was tested for chemical and organoleptic characteristics. The organoleptic characteristics of blends consist of taste and flavor, crust texture, fragrance and aroma, appearance, bendability, and overall acceptability were determined through taste panel by 213 judges. Forty Sprague Dawley rats were randomly given codes and allocated to different groups via tables with random numbers to feed on three DSF-fortified bread blends and control bread for 30 days. Results: The blending of wheat flour with DSF altered the organoleptic properties of breads. Addition of DSF increased significantly the protein and ash content of the bread (P < 0.05). Organoleptic test indicates that the best formulation is between 3 and 7% fortifications of DSF blends. In biological evaluation, rats fed the control diet had the lowest body weight gain and their food efficiency ratio was significantly different (P < 0.05) in compare with 7% DSF-fortified blend. Conclusions: It was concluded that overall acceptability score significantly decreased with increasing DSF substitution level. Rats fed 7% DSF-fortified blend showed privileged food efficiency ratio. Then, the best formulation is between 3 and 7% DSF bread. This formulation can nourish all human at risk of malnutrition. PMID:24554990

Ni Based Powder Reconditioning and Reuse for LMD Process

NASA Astrophysics Data System (ADS)

Renderos, M.; Girot, F.; Lamikiz, A.; Torregaray, A.; Saintier, N.

LMD is an additive manufacturing process based on the injection of metallic powder into a melt-pool created by a heat laser source on a substrate. One of the benefits of this technology is the reduction of the wasted material since it is a near-shape process. Moreover one of the main drawbacks is the relatively low efficiency of the trapped powder, which can be loss than 5% in some cases. The non-trapped powder represents a significant cost in the LMD process, since powder metal material is very expensive and usually is not reused. This article proposes a methodology of the reconditioning and posterior reuse of a nickel base powder commonly used in the aerospace industry, with the main objectives of cost saving, higher environmental cleanup and increase of the overall efficiency in the LMD process. The results are checked by the development of a prototype part built up from reused powder.

Non-Gold Base Dental Casting Alloys. Volume 2. Porcelain-Fused-to-Metal Alloys.

DTIC Science & Technology

1986-08-01

of the tooth . At the same time, enamel porcelains can be applied from the incisal one-third, through the middle one-third, and be subtly blended into...alumina (aluminum oxide) in a glass matrix. 1 Natural tooth color and opacification are obtained by the addition of metallic oxides to the porcelain...are classified as opaque, dentin (or body), and enamel (or incisal) porcelain powders with numerous color concentrates, such s opaque and dentin color

Alumina-based ceramic composite

DOEpatents

Alexander, Kathleen B.; Tiegs, Terry N.; Becher, Paul F.; Waters, Shirley B.

1996-01-01

An improved ceramic composite comprising oxide ceramic particulates, nonoxide ceramic particulates selected from the group consisting of carbides, borides, nitrides of silicon and transition metals and mixtures thereof, and a ductile binder selected from the group consisting of metallic, intermetallic alloys and mixtures thereof is described. The ceramic composite is made by blending powders of the ceramic particulates and the ductile to form a mixture and consolidating the mixture of under conditions of temperature and pressure sufficient to produce a densified ceramic composite.

Noninvasive Spatially Offset and Transmission Raman Mapping of Breast Tissue: A Multimodal Approach toward the in Vivo Assessment of Tissue Pathology

DTIC Science & Technology

2012-04-01

in breast cancer clinical practice and research to independently develop a new technology from a concept. My learning objectives include the...o ........... ...,. of laur .........,. ~: (1) tluo .. ,.. data ..... at I(,,II,P), (1) the raw valu. ot tluo tam %. polnla 1(..,, v, Ill) OJUIJ...technology (PAT) tool for the in-line monitoring and understanding of a powder blending process. ]oumtd of Phannaceu.tical and Biumedical Antdysis, 48

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

Häusler, I., E-mail: ines.haeusler@bam.de; Dörfel, I., E-mail: Ilona.doerfel@bam.de; Peplinski, B., E-mail: Burkhard.peplinski@bam.de

A model system was used to simulate the properties of tribofilms which form during automotive braking. The model system was prepared by ball milling of a blend of 70 vol.% iron oxides, 15 vol.% molybdenum disulfide and 15 vol.% graphite. The resulting mixture was characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and various transmission electron microscopic (TEM) methods, including energy dispersive X-ray spectroscopy (EDXS), high resolution investigations (HRTEM) with corresponding simulation of the HRTEM images, diffraction methods such as scanning nano-beam electron diffraction (SNBED) and selected area electron diffraction (SAED). It could be shown that the ballmore » milling caused a reduction of the grain size of the initial components to the nanometer range. Sometimes even amorphization or partial break-down of the crystal structure was observed for MoS{sub 2} and graphite. Moreover, chemical reactions lead to a formation of surface coverings of the nanoparticles by amorphous material, molybdenum oxides, and iron sulfates as derived from XPS. - Highlights: • Ball milling of iron oxides, MoS{sub 2}, and graphite to simulate a tribofilm • Increasing coefficient of friction after ball milling of the model blend • Drastically change of the diffraction pattern of the powder mixture • TEM & XPS showed the components of the milled mixture and the process during milling. • MoS{sub 2} and graphite suffered a loss in translation symmetry or became amorphous.« less

Gentamicin Sulfate PEG-PLGA/PLGA-H Nanoparticles: Screening Design and Antimicrobial Effect Evaluation toward Clinic Bacterial Isolates

PubMed Central

Dorati, Rossella; DeTrizio, Antonella; Spalla, Melissa; Migliavacca, Roberta; Pagani, Laura; Pisani, Silvia; Chiesa, Enrica; Modena, Tiziana; Genta, Ida

2018-01-01

Nanotechnology is a promising approach both for restoring or enhancing activity of old and conventional antimicrobial agents and for treating intracellular infections by providing intracellular targeting and sustained release of drug inside infected cells. The present paper introduces a formulation study of gentamicin loaded biodegradable nanoparticles (Nps). Solid-oil-in water technique was studied for gentamicin sulfate nanoencapsulation using uncapped Polylactide-co-glycolide (PLGA-H) and Polylactide-co-glycolide-co-Polyethylenglycol (PLGA-PEG) blends. Screening design was applied to optimize: drug payload, Nps size and size distribution, stability and resuspendability after freeze-drying. PLGA-PEG concentration resulted most significant factor influencing particles size and drug content (DC): 8 w/w% DC and 200 nm Nps were obtained. Stirring rate resulted most influencing factor for size distribution (PDI): 700 rpm permitted to obtain homogeneous Nps dispersion (PDI = 1). Further experimental parameters investigated, by 23 screening design, were: polymer blend composition (PLGA-PEG and PLGA-H), Polyvinylalcohol (PVA) and methanol concentrations into aqueous phase. Drug content was increased to 10.5 w/w%. Nanoparticle lyophilization was studied adding cryoprotectants, polyvinypirrolidone K17 and K32, and sodiumcarboxymetylcellulose. Freeze-drying protocol was optimized by a mixture design. A freeze-dried Nps powder free resuspendable with stable Nps size and payload, was developed. The powder was tested on clinic bacterial isolates demonstrating that after encapsulation, gentamicin sulfate kept its activity. PMID:29329209

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

Borkar, Tushar; Nag, Soumya; Ren, Yang

Coupled in situ alloying and nitridation of titanium–vanadium alloys, has been achieved by introducing reactive nitrogen gas during the spark plasma sintering (SPS) of blended titanium and vanadium elemental powders, leading to a new class of nitride reinforced titanium alloy composites. The resulting microstructure includes precipitates of the d-TiN phase with the NaCl structure, equiaxed (or globular) precipitates of a nitrogen enriched hcp a(Ti,N) phase with a c/a ratio more than what is expected for pure hcp Ti, and fine scale plate-shaped precipitates of hcp a-Ti, distributed within a bcc b matrix. During SPS processing, the d-TiN phase appears tomore » form at a temperature of 1400 C, while only hcp a(Ti,N) and a-Ti phases form at lower processing temperatures. Consequently, the highest microhardness is exhibited by the composite processed at 1400 C while those processed at 1300 C or below exhibit lower values. Processing at temperatures below 1300 C, resulted in an incomplete alloying of the blend of titanium and vanadium powders. These d-TiN precipitates act as heterogeneous nucleation sites for the a(Ti,N) precipitates that appear to engulf and exhibit an orientation relationship with the nitride phase at the center. Furthermore, fine scale a-Ti plates are precipitated within the nitride precipitates, presumably resulting from the retrograde solubility of nitrogen in titanium.« less

Experimental Investigation of Performance and emission characteristics of Various Nano Particles with Bio-Diesel blend on Di Diesel Engine

NASA Astrophysics Data System (ADS)

Karthik, N.; Goldwin Xavier, X.; Rajasekar, R.; Ganesh Bairavan, P.; Dhanseelan, S.

2017-05-01

Present study provides the effect of Zinc Oxide (ZnO) and Cerium Oxide (CeO2) nanoparticles additives on the Performance and emission uniqueness of Jatropha. Jatropha blended fuel is prepared by the emulsification technique with assist of mechanical agitator. Nano particles (Zinc Oxide (ZnO)) and Cerium Oxide (CeO2)) mixed with Jatropha blended fuel in mass fraction (100 ppm) with assist of an ultrasonicator. Experiments were conducted in single cylinder constant speed direct injection diesel engine for various test fuels. Performance results revealed that Brake Thermal Efficiency (BTE) of Jatropha blended Cerium Oxide (B20CE) is 3% and 11% higher than Jatropha blended zinc oxide (B20ZO) and Jatropha blended fuel (B20) and 4% lower than diesel fuel (D100) at full load conditions. Emission result shows that HC and CO emissions of Jatropha blended Cerium Oxide (B20CE) are (6%, 22%, 11% and 6%, 15%, 12%) less compared with Jatropha blended Zinc Oxide (B20ZO), diesel (D100) and Jatropha blended fuel (B20) at full load conditions. NOx emissions of Jatropha blended Cerium Oxide is 1 % higher than diesel fuel (D100) and 2% and 5% lower than Jatropha blended Zinc Oxide, and jatropha blended fuel.

Emissions characteristics of a diesel engine operating on biodiesel and biodiesel blended with ethanol and methanol.

PubMed

Zhu, Lei; Cheung, C S; Zhang, W G; Huang, Zhen

2010-01-15

Euro V diesel fuel, pure biodiesel and biodiesel blended with 5%, 10% and 15% of ethanol or methanol were tested on a 4-cylinder naturally-aspirated direct-injection diesel engine. Experiments were conducted under five engine loads at a steady speed of 1800 r/min. The study aims to investigate the effects of the blended fuels on reducing NO(x) and particulate. On the whole, compared with Euro V diesel fuel, the blended fuels could lead to reduction of both NO(x) and PM of a diesel engine, with the biodiesel-methanol blends being more effective than the biodiesel-ethanol blends. The effectiveness of NO(x) and particulate reductions is more effective with increase of alcohol in the blends. With high percentage of alcohol in the blends, the HC, CO emissions could increase and the brake thermal efficiency might be slightly reduced but the use of 5% blends could reduce the HC and CO emissions as well. With the diesel oxidation catalyst (DOC), the HC, CO and particulate emissions can be further reduced. Copyright 2009 Elsevier B.V. All rights reserved.

Experimental investigation on CRDI engine using butanol-biodiesel-diesel blends as fuel

NASA Astrophysics Data System (ADS)

Divakar Shetty, A. S.; Dineshkumar, L.; Koundinya, Sandeep; Mane, Swetha K.

2017-07-01

In this research work an experimental investigation of butanol-biodisel-diesel blends on combustion, performance and emission characteristics of a direct injection (DI) diesel engine is carried out. The blends are prepared at different proportions and fuel properties such as calorific value, viscosity, flash point and fire point, cloud point, pour point of butanol (B), biodiesel (B), diesel (D), biodiesel-diesel (BD) blends and butanol-biodiesel-diesel (BBD) blends are determined. The engine test is conducted at different speed and load. From the results obtained for fuel properties we can observe that the flash, fire and pour point, viscosity and density are decreasing by increasing the percentage of butanol in BBD blends. It is also observed that the performance parameters such as brake thermal efficiency (BTE) and exhaust gas temperature increases with increase in the proportion of butanol in BBD blend. However, the brake specific fuel consumption (BFSC) decreases with increase in the proportion of butanol in BBD blend. The increase of butanol in BBD blends also influence to increase on emission characteristic such as carbon monoxide (CO), hydrocarbon (HC) and oxides of nitrogen (NOx).

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

Liu, Zhi-jie; Dai, Le-yang; Yang, De-zheng

Highlights: • A novel and high efficiency synthesizing AlN powders method combining mechanical ball milling and DBDP has been developed. • The particle size, the crystallite size, the lattice distortion, the morphology of Al{sub 2}O{sub 3} powders, and the AlN conversion rate are investigated and compared under the ball milled Al{sub 2}O{sub 3} powders with DBDP and without DBDP. • The ball milled Al{sub 2}O{sub 3} powders with DBDP have small spherical structure morphology with very fine particles size and high specific surface area, which result in a higher chemical efficiency and a higher AlN conversion rate at lower thermalmore » temperature. - Abstract: In this paper, aluminum nitride (AlN) powers have been produced with a novel and high efficiency method by thermal annealing at 1100–1600 °C of alumina (Al{sub 2}O{sub 3}) powders which were previously ball milled for various time up to 40 h with and without the assistant of dielectric barrier discharge plasma (DBDP). The ball milled Al{sub 2}O{sub 3} powders with DBDP and without DBDP and the corresponding synthesized AlN powers are characterized by X-ray diffraction, scanning electron microscope, and transmission electron microscopy. From the characteristics of the ball milled Al{sub 2}O{sub 3} powders with DBDP and without DBDP, it can be seen that the ball milled Al{sub 2}O{sub 3} powders with DBDP have small spherical structure morphology with very fine particles size and high specific surface area, which result in a higher chemical efficiency and a higher AlN conversion rate at lower thermal temperature. Meanwhile, the synthesized AlN powders can be known as hexagonal AlN with fine crystal morphology and irregular lump-like structure, and have uniform distribution with the average particle size of about between 500 nm and 1000 nm. This provides an important method for fabricating ultra fine powders and synthesizing nitrogen compounds.« less

Electrospinning of ceramic nanofibers

NASA Astrophysics Data System (ADS)

Eick, Benjamin M.

Silicon Carbide (SiC) nanofibers of diameters as low as 20 nm are fabricated. The fibers were produced through the electrostatic spinning of the preceramic poly(carbomethylsilane) with pyrolysis to ceramic. A new technique was used where the preceramic was blended with polystyrene (PS) and, subsequent to electrospinning, was exposed to UV to crosslink the PS and prevent fibers flowing during pyrolysis. Electrospun SiC fibers were characterized by FTIR, TGA-DTA, SEM, TEM, XRD, and SAED. Fibers were shown to be polycrystalline and nanograined with alpha-SiC 15R polytype being dominant, where commercial fiber production methods form beta-SiC 3C. Pyrolysis of the bulk polymer blend to SiC produced alpha-SiC 15R as the dominant polytype with larger grains showing that electrospinning nanofibers affects resultant crystallinity. Fibers produced were shown to have a core-shell structure of an oxide scale that was variable by pyrolysis conditions. Metal oxide powders (chromium oxide, cobalt oxide, iron oxide, silicon oxide, tantalum oxide, titanium oxide, tungsten oxide, vanadium oxide, and zirconium oxide), were converted to metal carbide powders and metal nitride powders by the process of carbothermal reduction (CTR). Synthetic pitch was explored as an alternative to graphite which is a common carbon source for CTR. It was shown via characterization with XRD that pitch performs as well and in some cases better than graphite and is therefore a viable alternative in CTR. Conversion of metal oxide powders with pitch led to conversion of sol-gel based metal oxide nanofibers produced by electrospinning. Pitch was soluble in the solutions xv that were electrospun allowing for intimate contact between the sol-gel and the carbon source for CTR. This method became a two step processing method to produce metal carbide and nitride nanofibers: first electrospin sol-gel based metal oxide nanofibers and subsequently pyrolize them in the manner of CTR to transform them. Results indicate that this method was capable of transforming hafnium, niobium, tantalum, titanium, vanadium, and zirconium sol-gel nanofibers to metal carbides and nitrides.

Influence of low-temperature combustion and dimethyl ether-diesel blends on performance, combustion, and emission characteristics of common rail diesel engine: a CFD study.

PubMed

Lamani, Venkatesh Tavareppa; Yadav, Ajay Kumar; Narayanappa, Kumar Gottekere

2017-06-01

Due to presence of more oxygen, absence of carbon-carbon (C-C) bond in chemical structure, and high cetane number of dimethyl ether (DME), pollution from DME operated engine is less compared to diesel engine. Hence, the DME can be a promising alternative fuel for diesel engine. The present study emphasizes the effect of various exhaust gas recirculation (EGR) rates (0-20%) and DME/Diesel blends (0-20%) on combustion characteristics and exhaust emissions of common rail direct injection (CRDI) engine using three-dimensional computational fluid dynamics (CFD) simulation. Extended coherent flame model-3 zone (ECFM-3Z) is implemented to carry out combustion analysis, and k-ξ-f model is employed for turbulence modeling. Results show that in-cylinder pressure marginally decreases with employing EGR compared to without EGR case. As EGR rate increases, nitrogen oxide (NO) formation decreases, whereas soot increases marginally. Due to better combustion characteristics of DME, indicated thermal efficiency (ITE) increases with the increases in DME/diesel blend ratio. Adverse effect of EGR on efficiency for blends is less compared to neat diesel, because the anoxygenated region created due to EGR is compensated by extra oxygen present in DME. The trade-off among NO, soot, carbon monoxide (CO) formation, and efficiency is studied by normalizing the parameters. Optimum operating condition is found at 10% EGR rate and 20% DME/diesel blend. The maximum indicated thermal efficiency was observed for DME/diesel ratio of 20% in the present range of study. Obtained results are validated with published experimental data and found good agreement.

Luminescence of powdered uranium glasses

NASA Technical Reports Server (NTRS)

Eubanks, A. G.; Mcgarrity, J. M.; Silverman, J.

1974-01-01

Measurement of cathodoluminescence and photoluminescence efficiencies in powdered borosilicate glasses having different particle size and different uranium content. Excitation with 100 to 350 keV electrons and with 253.7 nm light was found to produce identical absolute radiant exitance spectra in powdered samples. The most efficient glass was one containing 29.4 wt% B2O3, 58.8 wt% SiO2, 9.8 wt% Na2O and 2.0 wt% UO2.

Phthalocyanine Blends Improve Bulk Heterojunction Solar Cells

PubMed Central

Varotto, Alessandro; Nam, Chang-Yong; Radivojevic, Ivana; Tomé, Joao; Cavaleiro, José A.S.; Black, Charles T.; Drain, Charles Michael

2010-01-01

A core phthalocyanine platform allows engineering the solubility properties the band gap; shifting the maximum absorption toward the red. A simple method to increase the efficiency of heterojunction solar cells uses a self-organized blend of the phthalocyanine chromophores fabricated by solution processing. PMID:20136126

Charge carrier transport and photogeneration in P3HT:PCBM photovoltaic blends.

PubMed

Laquai, Frédéric; Andrienko, Denis; Mauer, Ralf; Blom, Paul W M

2015-06-01

This article reviews the charge transport and photogeneration in bulk-heterojunction solar cells made from blend films of regioregular poly(3-hexylthiophene) (RR-P3HT) and methano-fullerene (PCBM). The charge transport, specifically the hole mobility in the RR-P3HT phase of the polymer:fullerene photovoltaic blend, is dramatically affected by thermal annealing. The hole mobility increases more than three orders of magnitude and reaches a value of up to 2 × 10(-4) cm(2) V(-1) s(-1) after the thermal annealing process as a result of an improved semi-crystallinity of the film. This significant increase of the hole mobility balances the electron and hole mobilities in a photovoltaic blend in turn reducing space-charge formation, and this is the most important factor for the strong enhancement of the photovoltaic efficiency compared to an as cast, that is, non-annealed device. In fact, the balanced charge carrier mobility in RR-P3HT:PCBM blends in combination with a field- and temperature-independent charge carrier generation and greatly reduced non-geminate recombination explains the large quantum efficiencies mea-sured in P3HT:PCBM photovoltaic devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparative study of performance and emissions of a CI engine using biodiesel of microalgae, macroalgae and rice bran

NASA Astrophysics Data System (ADS)

Jayaprabakar, J.; Karthikeyan, A.; Saikiran, K.; Beemkumar, N.; Joy, Nivin

2017-05-01

Biodiesel is an alternative and safe fuel to replace conventional petroleum diesel. With high-lubricity and clean-burning ability the biodiesel can be a better fuel component for use in existing diesel engines without any modifications. The aim of this Research was to study the potential use of Macro algae oil, Micro algae oil, Rice Bran oil methyl ester as a substitute for diesel fuel in diesel engine. B10 and B20 blends of these three types of fuels are prepared by transesterification process. The blends on volume basis were used to test them in a four stroke single cylinder diesel engine to study the performance and emission characteristics of these fuels and compared with neat diesel fuel. Also, the property testing of these biofuels were carried out. The biodiesel blends in this study substantially reduces the emission of unburnt hydro carbons and smoke opacity and increases the emission of NOx emission in exhaust gases. These biodiesel blends were consumed more by the engine during testing than Diesel and the brake thermal efficiency and volumetric efficiency for the blends was identical with the Diesel.

Ternary Organic Solar Cells Based on Two Compatible Nonfullerene Acceptors with Power Conversion Efficiency >10.

PubMed

Liu, Tao; Guo, Yuan; Yi, Yuanping; Huo, Lijun; Xue, Xiaonan; Sun, Xiaobo; Fu, Huiting; Xiong, Wentao; Meng, Dong; Wang, Zhaohui; Liu, Feng; Russell, Thomas P; Sun, Yanming

2016-12-01

Two different nonfullerene acceptors and one copolymer are used to fabricate ternary organic solar cells (OSCs). The two acceptors show unique interactions that reduce crystallinity and form a homogeneous mixed phase in the blend film, leading to a high efficiency of ≈10.3%, the highest performance reported for nonfullerene ternary blends. This work provides a new approach to fabricate high-performance OSCs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chemical Dynamics of nano-Aluminum and Iodine Based Oxidizers

NASA Astrophysics Data System (ADS)

Little, Brian; Ridge, Claron; Overdeep, Kyle; Slizewski, Dylan; Lindsay, Michael

2017-06-01

As observed in previous studies of nanoenergetic powder composites, micro/nano-structural features such as particle morphology and/or reactant spatial distance are expected to strongly influence properties that govern the combustion behavior of energetic materials (EM). In this study, highly reactive composites containing crystalline iodine (V) oxide or iodate salts with nano-sized aluminum (nAl) were blended by two different processing techniques and then collected as a powder for characterization. Physiochemical techniques such as thermal gravimetric analysis, calorimetry, X-ray diffraction, electron microscopy, high speed photography, pressure profile analysis, temperature programmed reactions, and spectroscopy were employed to characterize these EM with emphasis on correlating the chemical reactivity with inherent structural features and variations in stoichiometry. This work is a continuation of efforts to probe the chemical dynamics of nAl-iodine based composites.

Decoration of multi-walled carbon nanotubes by polymer wrapping and its application in MWCNT/polyethylene composites

PubMed Central

2012-01-01

We dispersed the non-covalent functionalization of multi-walled carbon nanotubes (CNTs) with a polymer dispersant and obtained a powder of polymer-wrapped CNTs. The UV–vis absorption spectrum was used to investigate the optimal weight ratio of the CNTs and polymer dispersant. The powder of polymer-wrapped CNTs had improved the drawbacks of CNTs of being lightweight and difficult to process, and it can re-disperse in a solvent. Then, we blended the polymer-wrapped CNTs and polyethylene (PE) by melt-mixing and produced a conductive masterbatch and CNT/PE composites. The polymer-wrapped CNTs showed lower surface resistivity in composites than the raw CNTs. The scanning electron microscopy images also showed that the polymer-wrapped CNTs can disperse well in composites than the raw CNTs. PMID:22559082

Comparison of bacterial counts obtained from naturally contaminated foods by means of Stomacher and blender.

PubMed

Purvis, U; Sharpe, A N; Bergener, D M; Lachapelle, G; Milling, M; Spiring, F

1987-01-01

Four Regional Health Protection Branch laboratories each compared aerobic colony counts obtained after "stomaching" and blending, for a minimum of 10 samples in each of the seven food groups: dry pastas; chocolate and cocoa powders; frozen entrees (macaroni and cheese, chow mein, chop suey, fried rice, seafood casseroles, and Salisbury steak); nonfat dry milk; shrimp and crabmeats; spices; and breakfast sausages. Overall, counts obtained after using the Stomacher were equivalent to or higher than counts obtained after using the blender in 73% of the comparisons (alpha = 0.05). Where differences existed, counts obtained after using the Stomacher tended to be higher than counts obtained after using the blender from milk powder and lower from sausage. Aerobic colony counts from these foods are not unacceptably biased when obtained by Stomacher.

Feasibility study of the production of biomedical Ti-6Al-4V alloy by powder metallurgy.

PubMed

Bolzoni, L; Ruiz-Navas, E M; Gordo, E

2015-04-01

Titanium and its alloys are characterized by an exceptional combination of properties like high strength, good corrosion resistance and biocompatibility which makes them suitable materials for biomedical prosthesis and devices. The wrought Ti-6Al-4V alloy is generally favored in comparison to other metallic biomaterials due to its relatively low elastic modulus and it has been long used to obtain products for biomedical applications. In this work an alternative route to fabricate biomedical implants made out of the Ti-6Al-4V alloy is investigated. Specifically, the feasibility of the conventional powder metallurgy route of cold uniaxial pressing and sintering is addressed by considering two types of powders (i.e. blended elemental and prealloyed). The characterization of physical properties, chemical analysis, mechanical behavior and microstructural analysis is carried out in-depth and the properties are correlated among them. On the base of the results found, the produced alloys are promising materials for biomedical applications as well as cheaper surgical devices and tools. Copyright © 2015 Elsevier B.V. All rights reserved.

Mechanical behaviour of pressed and sintered titanium alloys obtained from master alloy addition powders.

PubMed

Bolzoni, L; Esteban, P G; Ruiz-Navas, E M; Gordo, E

2012-11-01

The fabrication of the workhorse Ti-6Al-4V alloy and of the Ti-3Al-2.5V alloy was studied considering the master alloy addition variant of the blending elemental approach conventionally used for titanium powder metallurgy. The powders were characterised by means thermal analysis and X-ray diffraction and shaped by means of uniaxial pressing. The microstructural evolution with the sintering temperature (900-1400 °C) was evaluated by SEM and EDS was used to study the composition. XRD patterns as well as the density by Archimedes method were also obtained. The results indicate that master alloy addition is a suitable way to fabricate well developed titanium alloy but also to produce alloy with the desired composition, not available commercially. Density of 4.3 g/cm³ can be obtained where a temperature higher than 1200 °C is needed for the complete diffusion of the alloying elements. Flexural properties comparable to those specified for wrought Ti-6Al-4V medical devices are, generally, obtained. Copyright © 2012 Elsevier Ltd. All rights reserved.

Functional properties of gluten-free pasta produced from amaranth, quinoa and buckwheat.

PubMed

Schoenlechner, Regine; Drausinger, Julian; Ottenschlaeger, Veronika; Jurackova, Katerina; Berghofer, Emmerich

2010-12-01

The use of amaranth, quinoa and buckwheat for the production of gluten-free pasta was investigated in the present study. The aim of the work was to produce pasta of good textural quality, in particular, low cooking loss, optimal cooking weight and texture firmness. The results demonstrated that pasta produced from amaranth had decreased texture firmness and cooking time, while pasta from quinoa mainly showed increased cooking loss. In buckwheat pasta the least negative effects were observed. By combination of all three raw materials to one flour blend in the ratio of 60% buckwheat, 20% amaranth and 20% quinoa, dough matrix was improved. After decreasing dough moisture to 30%, addition of an increased amount of egg white powder of 6% and addition of 1.2% emulsifier (distilled monoglycerides) texture firmness as well as cooking quality of gluten-free pasta produced from such a flour blend reached acceptable values comparable to wheat pasta.

A novel particle engineering technology to enhance dissolution of poorly water soluble drugs: spray-freezing into liquid.

PubMed

Rogers, True L; Nelsen, Andrew C; Hu, Jiahui; Brown, Judith N; Sarkari, Marazban; Young, Timothy J; Johnston, Keith P; Williams, Robert O

2002-11-01

A novel cryogenic spray-freezing into liquid (SFL) process was developed to produce microparticulate powders consisting of an active pharmaceutical ingredient (API) molecularly embedded within a pharmaceutical excipient matrix. In the SFL process, a feed solution containing the API was atomized beneath the surface of a cryogenic liquid such that the liquid-liquid impingement between the feed and cryogenic liquids resulted in intense atomization into microdroplets, which were frozen instantaneously into microparticles. The SFL micronized powder was obtained following lyophilization of the frozen microparticles. The objective of this study was to develop a particle engineering technology to produce micronized powders of the hydrophobic drug, danazol, complexed with hydroxypropyl-beta-cyclodextrin (HPbetaCD) and to compare these SFL micronized powders to inclusion complex powders produced from other techniques, such as co-grinding of dry powder mixtures and lyophilization of bulk solutions. Danazol and HPbetaCD were dissolved in a water/tetrahydrofuran cosolvent mixture prior to SFL processing or slow freezing. Identical quantities of the API and HPbetaCD used in the solutions were co-ground in a mortar and pestle and blended to produce a co-ground physical mixture for comparison. The powder samples were characterized by differential scanning calorimetry (DSC), powder X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), scanning electron microscopy, surface area analysis, and dissolution testing. The results provided by DSC, XRD, and FTIR suggested the formation of inclusion complexes by both slow-freezing and SFL. However, the specific surface area was significantly higher for the latter. Dissolution results suggested that equilibration of the danazol/HPbetaCD solution prior to SFL processing was required to produce the most soluble conformation of the resulting inclusion complex following SFL. SFL micronized powders exhibited better dissolution profiles than the slowly frozen aggregate powder. Results indicated that micronized SFL inclusion complex powders dissolved faster in aqueous dissolution media than inclusion complexes formed by conventional techniques due to higher surface areas and stabilized inclusion complexes obtained by ultra-rapid freezing.

Use of limestone powder during incorporation of Pb-containing cathode ray tube waste in self-compacting concrete.

PubMed

Sua-iam, Gritsada; Makul, Natt

2013-10-15

For several decades, cathode ray tubes (CRTs) were the primary display component of televisions and computers. The CRT glass envelope contains sufficient levels of lead oxide (PbO) to be considered hazardous, and there is a need for effective methods of permanently encapsulating this material during waste disposal. We examined the effect of adding limestone powder (LS) on the fresh and cured properties of self-compacting concrete (SCC) mixtures containing waste CRT glass. The SCC mixtures were prepared using Type 1 Portland cement at a constant cement content of 600 kg/m(3) and a water-to-cement ratio (w/c) of 0.38. CRT glass waste cullet was blended with river sand in proportions of 20 or 40% by weight. To suppress potential viscosity effects limestone powder was added at levels of 5, 10, or 15% by weight. The slump flow time, slump flow diameter, V-funnel flow time, Marsh cone flow time, and setting time of the fresh concrete were tested, as well as the compressive strength and ultrasonic pulse velocity of the hardened concrete. Addition of limestone powder improved the fresh and hardened properties. Pb leaching levels from the cured concrete were within US EPA allowable limits. Copyright © 2013 Elsevier Ltd. All rights reserved.

Influence of amorphous content on compaction behaviour of anhydrous alpha-lactose.

PubMed

Ziffels, S; Steckel, H

2010-03-15

Modified lactoses are widely used as filler-binders in direct compression of tablets. Until today, little about the compaction behaviour of anhydrous alpha-lactose is known. In this study, a new method to prepare anhydrous alpha-lactose from alpha-lactose monohydrate by desiccation with heated ethanol was evaluated and the influence of amorphous content in the lactose powder prior to modification on powder properties, compaction behaviour and storage stability was determined. The modification process led to anhydrous alpha-lactose with decreased bulk and tapped density, increased flow rate and significantly higher specific surface area. Due to the higher specific surface area, the compaction behaviour of the anhydrous alpha-lactose was found to be significantly better than the compaction behaviour of powder blends consisting of alpha-lactose monohydrate and amorphous lactose. An influence of the amorphous content prior to modification could be observed only at higher compaction forces. In general, tablets of modified powders needed longer time to disintegrate directly after compression. However, the storage stability of modified tablets was found to be better compared to the amorphous-crystalline tablets which were influenced by storage conditions, initial crushing strength as well as amorphous content due to the re-crystallization of amorphous lactose during storage. 2009 Elsevier B.V. All rights reserved.

Blackbody material

DOEpatents

Lauf, Robert J.; Hamby, Jr., Clyde; Akerman, M. Alfred; Trivelpiece, Alvin W.

1994-01-01

A light emitting article comprises a composite of carbon-bonded carbon fibers, prepared by: blending carbon fibers with a carbonizable organic powder to form a mixture; dispersing the mixture into an aqueous slurry; vacuum molding the aqueous slurry to form a green article; drying and curing the green article to form a cured article; and, carbonizing the cured article at a temperature of at least about 1000.degree. C. to form a carbon-bonded carbon fiber light emitting composite article having a bulk density less than 1 g/cm.sup.3.

Characterization and microstructure of HPMC/Gly:AgNO3 polymer composites

NASA Astrophysics Data System (ADS)

Ananda, H. T.; Urs, G. Thejas; Somashekar, R.

2018-04-01

This study reports the synthesis and characterization of AgNo3 doped HPMC/Glycerol blend films. The microstructural parameters of these composites were evaluated employing whole powder pattern fitting method (WPPF) and the results obtained are related with other physical properties. AC conductivity results and optical band gap evaluated from UV/Vis studies are focused to establish structure property relations. These composite films are bio-degradable in nature and non-hazardous, this makes them very suitable candidates for applications in appropriate fields.

Alumina-based ceramic composite

DOEpatents

Alexander, K.B.; Tiegs, T.N.; Becher, P.F.; Waters, S.B.

1996-07-23

An improved ceramic composite comprising oxide ceramic particulates, nonoxide ceramic particulates selected from the group consisting of carbides, borides, nitrides of silicon and transition metals and mixtures thereof, and a ductile binder selected from the group consisting of metallic, intermetallic alloys and mixtures thereof is described. The ceramic composite is made by blending powders of the ceramic particulates and the ductile to form a mixture and consolidating the mixture of under conditions of temperature and pressure sufficient to produce a densified ceramic composite. 5 figs.

Quality control of the tribological coating PS212

NASA Technical Reports Server (NTRS)

Sliney, Harold E.; Dellacorte, Christopher; Deadmore, Daniel L.

1989-01-01

PS212 is a self-lubricating, composite coating that is applied by the plasma spray process. It is a functional lubricating coating from 25 C (or lower) to 900 C. The coating is prepared from a blend of three different powders with very dissimilar properties. Therefore, the final chemical composition and lubricating effectiveness of the coatings are very sensitive to the process variables used in their preparation. Defined here are the relevant variables. The process and analytical procedures that will result in satisfactory tribological coatings are discussed.

Review of Portable, Manually Operated, and Non-Total Flooding Fire Extinguishing Technologies for Use on Naval Vessels

DTIC Science & Technology

2011-12-01

Corrosion problems arising from the use of perfluoro-or hydrofluorocarbon agents have been investigated and are of concern. The concern centers on the...which was formerly known as Powdered Aerosol B, can be used on Class A, Class B, and Class C fires. These agents are a blend of several halocarbons...Canada Review of Portable, Manually Operated, and Non-Total Flooding Fire Extinguishing Technologies for Use on Naval Vessels Contract Project Manager

Ternary Blend Composed of Two Organic Donors and One Acceptor for Active Layer of High-Performance Organic Solar Cells.

PubMed

Lee, Jong Won; Choi, Yoon Suk; Ahn, Hyungju; Jo, Won Ho

2016-05-04

Ternary blends composed of two donor absorbers with complementary absorptions provide an opportunity to enhance the short-circuit current and thus the power conversion efficiency (PCE) of organic solar cells. In addition to complementary absorption of two donors, ternary blends may exhibit favorable morphology for high-performance solar cells when one chooses properly the donor pair. For this purpose, we develop a ternary blend with two donors (diketopyrrolopyrrole-based polymer (PTDPP2T) and small molecule ((TDPP)2Ph)) and one acceptor (PC71BM). The solar cell made of a ternary blend with 10 wt % (TDPP)2Ph exhibits higher PCE of 7.49% as compared with the solar cells with binary blends, PTDPP2T:PC71BM (6.58%) and (TDPP)2Ph:PC71BM (3.21%). The higher PCE of the ternary blend solar cell is attributed mainly to complementary absorption of two donors. However, a further increase in (TDPP)2Ph content in the ternary blend (>10 wt %) decreases the PCE. The ternary blend with 10 wt % (TDPP)2Ph exhibits well-developed morphology with narrow-sized fibrils while the blend with 15 wt % (TDPP)2Ph shows phase separation with large-sized domains, demonstrating that the phase morphology and compatibility of ternary blend are important factors to achieve a high-performance solar cell made of ternary blends.

Blended learning in K-12 mathematics and science instruction -- An exploratory study

NASA Astrophysics Data System (ADS)

Schmidt, Jason

Blended learning has developed into a hot topic in education over the past several years. Flipped classrooms, online learning environments, and the use of technology to deliver educational content using rich media continue to garner national attention. While generally well accepted and researched in post-secondary education, not much research has focused on blended learning in elementary, middle, and high schools. This thesis is an exploratory study to begin to determine if students and teachers like blended learning and whether or not it affects the amount of time they spend in math and science. Standardized achievement test data were also analyzed to determine if blended learning had any effect on test scores. Based on student and teacher surveys, this population seems to like blended learning and to work more efficiently in this environment. There is no evidence from this study to support any effect on student achievement.

Controlling the Solidification of Organic Photovoltaic Blends with Nucleating Agents

NASA Astrophysics Data System (ADS)

Nekuda Malik, Jennifer A.; Treat, Neil D.; Abdelsamie, Maged; Yu, Liyang; Li, Ruipeng; Smilgies, Detlef-M.; Amassian, Aram; Hawker, Craig J.; Chabinyc, Michael L.; Stingelin, Natalie

2014-11-01

Blending fullerenes with a donor polymer for the fabrication of organic solar cells often leads to at least partial vitrification of one, if not both, components. For prototypical poly(3-hexylthiophene):fullerene blend, we show that the addition of a commercial nucleating agent, di(3,4-dimethyl benzylidene)sorbitol, to such binary blends accelerates the crystallization of the donor, resulting in an increase in its degree of crystallinity in as-cast structures. This allows manipulation of the extent of intermixing/ phase separation of the donor and acceptor directly from solution, offering a tool to improve device characteristics such as power conversion efficiency.

Comparative effects of MTBE and ethanol additions into gasoline on exhaust emissions

NASA Astrophysics Data System (ADS)

Song, Chong-Lin; Zhang, Wen-Mei; Pei, Yi-Qiang; Fan, Guo-Liang; Xu, Guan-Peng

The effects of the additives of ethanol (EA) and methyl tert-butyl ether (MTBE) in various blend ratios into the gasoline fuel on the exhaust emissions and the catalytic conversion efficiencies were investigated in an EFI gasoline engine. The regulated exhaust emissions (CO, THC and NO X) and the unregulated exhaust emissions (benzene, formaldehyde, acetaldehyde, unburned EA and MTBE) before and after the three-way catalytic converter were measured. The experimental results showed that EA brought about generally lower regulated engine-out emissions than MTBE did. But, the comparison of the unregulated engine-out emissions between both additives was different. Concretely, the effect of EA on benzene emission was worse than that of MTBE on the whole, which was a contrast with formaldehyde emission. The difference in the acetaldehyde comparison depended much on the engine operating conditions, especially the engine speed. Both EA and MTBE were identified in the engine exhaust gases only when they were added to the fuel, and their volume fraction increased with blend ratios. The catalytic conversion efficiencies of the regulated emissions for the EA blends were in general lower than those for MTBE blends, especially at the low and high engine speeds. There was little difference in the catalytic conversion efficiencies for both benzene and formaldehyde, while distinct difference for acetaldehyde.

Pyrogasification of blended animal manures to produce combustable gas and biochar

USDA-ARS?s Scientific Manuscript database

The objective of this study is to evaluate the efficiency of a skid-mounted pyrogasificaiton system for producing combustible gas from from animal manures: chicken litter, swine solids, and swine solids blended with rye grass. The skid-mounted pyrolysis system by the US Innovation Group, Inc. (USIG,...

Predicting the concentration and specific gravity of biodiesel-diesel blends using near-infrared spectroscopy

USDA-ARS?s Scientific Manuscript database

Biodiesel made from different source materials usually have different physical and chemical properties and the concentration of biodiesel in biodiesel-diesel blends varies from pump to pump and from user to user; all these factors have significant effects on performance and efficiency of engines fue...

The efficient n-doping of [6,6]-phenyl C61-butyric acid methyl ester by leuco-crystal violet to enhance the performance of inverted organic solar cells

NASA Astrophysics Data System (ADS)

Chen, Li; Zhao, Wei; Cao, Huan; Shi, Zhihua; Zhang, Jidong; Qin, Dashan

2018-02-01

Inverted organic solar cells (OSCs) have been fabricated using the photoactive blend thin films based on regioregular poly(3-hexylthiophene) (P3HT), [6,6]-phenyl C61-butyric acid methyl ester (PCBM), and leuco-crystal violet (LCV). It was found that the LCV as an efficient n-dopant could significantly increase intrinsic electron concentration of PCBM zone. The electron mobility of P3HT:PCBM:LCV blend thin film was measured 1.75 times as high as that of P3HT:PCBM blend thin film, as a result of LCV-induced trap filling in the bandgap of PCBM. The power conversion efficiency for the inverted device using the photoactive layer of P3HT:PCBM:LCV could be 1.22 times as high as that for the inverted device using the conventional photoactive layer of P3HT:PCBM, mostly because (1) the higher electron mobility could enhance the exciton dissociation and thereby short-circuit current density in the former relative to the latter; (2) the increase in the electron concentration of PCBM zone in P3HT:PCBM:LCV blend thin film may help blocking holes diffusion towards cathode, improving the hole collection efficiency and thereby fill factor of device. We provide a new insight on optimizing the electron-conducting property of bulk-heterojunction photoactive thin film, useful for pushing forward inverted OSCs towards the cost-effective commercialization.

Heat Treatment of Gas-Atomized Powders for Cold Spray Deposition

NASA Astrophysics Data System (ADS)

Story, William A.; Brewer, Luke N.

2018-02-01

This communication demonstrates the efficacy of heat treatment on the improved deposition characteristics of aluminum alloy powders. A novel furnace was constructed for solutionizing of feedstock powders in an inert atmosphere while avoiding sintering. This furnace design achieved sufficiently high cooling rates to limit re-precipitation during powder cooling. Microscopy showed homogenization of the powder particle microstructures after heat treatment. Cold spray deposition efficiency with heat-treated powders substantially increased for the alloys AA2024, AA6061, and AA7075.

Improved crystallinity and dynamic mechanical properties of reclaimed waste tire rubber/EVA blends under the influence of electron beam irradiation

NASA Astrophysics Data System (ADS)

Ramarad, Suganti; Ratnam, Chantara T.; Khalid, Mohammad; Chuah, Abdullah Luqman; Hanson, Svenja

2017-01-01

Dependence on automobiles has led to a huge amount of waste tires produced annually around the globe. In this study, the feasibility of recycling these waste tires by blending reclaimed waste tire rubber (RTR) with poly(ethylene-co-vinyl acetate) (EVA) and electron beam irradiation was studied. The RTR/EVA blends containing 100-0 wt% of RTR were prepared in the internal mixer followed by electron beam (EB) irradiation with doses ranging from 50 to 200 kGy. The processing torques, calorimetric and dynamic mechanical properties of the blends were studied. Blends were found to have lower processing torque indicating easier processability of RTR/EVA blends compared to EVA. RTR domains were found to be dispersed in EVA matrix, whereas, irradiation improved the dispersion of RTR into smaller domains in EVA matrix. Results showed the addition of EVA improves the efficiency of irradiation induced crosslink formation and dynamic mechanical properties of the blends at the expense of the calorimetric properties. Storage and loss modulus of 50 wt% RTR blend was higher than RTR and EVA, suggesting partial miscibility of the blend. Whereas, electron beam irradiation improved the calorimetric properties and dynamic mechanical properties of the blends through redistribution of RTR in smaller domain sizes within EVA.

High-Octane Mid-Level Ethanol Blend Market Assessment

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

Johnson, Caley; Newes, Emily; Brooker, Aaron

2015-12-01

The United States government has been promoting increased use of biofuels, including ethanol from non-food feedstocks, through policies contained in the Energy Independence and Security Act of 2007. The objective is to enhance energy security, reduce greenhouse gas (GHG) emissions, and provide economic benefits. However, the United States has reached the ethanol blend wall, where more ethanol is produced domestically than can be blended into standard gasoline. Nearly all ethanol is blended at 10 volume percent (vol%) in gasoline. At the same time, the introduction of more stringent standards for fuel economy and GHG tailpipe emissions is driving research tomore » increase the efficiency of spark ignition (SI) engines. Advanced strategies for increasing SI engine efficiency are enabled by higher octane number (more highly knock-resistant) fuels. Ethanol has a research octane number (RON) of 109, compared to typical U.S. regular gasoline at 91-93. Accordingly, high RON ethanol blends containing 20 vol% to 40 vol% ethanol are being extensively studied as fuels that enable design of more efficient engines. These blends are referred to as high-octane fuel (HOF) in this report. HOF could enable dramatic growth in the U.S. ethanol industry, with consequent energy security and GHG emission benefits, while also supporting introduction of more efficient vehicles. HOF could provide the additional ethanol demand necessary for more widespread deployment of cellulosic ethanol. However, the potential of HOF can be realized only if it is adopted by the motor fuel marketplace. This study assesses the feasibility, economics, and logistics of this adoption by the four required participants--drivers, vehicle manufacturers, fuel retailers, and fuel producers. It first assesses the benefits that could motivate these participants to adopt HOF. Then it focuses on the drawbacks and barriers that these participants could face when adopting HOF and proposes strategies--including incentives and policies--to curtail these barriers. These curtailment strategies are grouped into scenarios that are then modeled to investigate their feasibility and explore the dynamics involved in HOF deployment. This report does not advocate for or against incentives or policies, but presents simulations of their effects.« less

Charge transfer in the weak driving force limit in blends of MDMO-PPV and dithienylthiazolo[5,4-d]thiazoles towards organic photovoltaics with high V(OC).

PubMed

Nevil, Nissy; Ling, Yun; Van Mierloo, Sarah; Kesters, Jurgen; Piersimoni, Fortunato; Adriaensens, Peter; Lutsen, Laurence; Vanderzande, Dirk; Manca, Jean; Maes, Wouter; Van Doorslaer, Sabine; Goovaerts, Etienne

2012-12-05

A series of three 5'-aryl-2,5-dithienylthiazolo[5,4-d]thiazole (DTTzTz) semiconducting molecules with different aryl substituents has been investigated as alternative acceptor materials in combination with the donor polymer poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene] (MDMO-PPV) in order to evaluate the photoinduced charge transfer (CT) efficiency in the resulting blends, designed towards possible application in organic photovoltaics. Photoluminescence quenching together with polaron detection by electron paramagnetic resonance and photoinduced absorption (PIA) demonstrate an increasing charge transfer efficiency when the DTTzTz substituents are varied from thien-2-yl to 4-trifluoromethylphenyl and 4-cyanophenyl groups, correlating well with the increasing acceptor strength in this series of molecules. In line with this observation, there is a decrease in the effective optical bandgap relative to pure MDMO-PPV that becomes more pronounced along this series of acceptor compounds, reaching 0.12 eV in the blend with 4-CN-Ph-DTTzTz. Intermolecular interactions between the blend components lead to lower energy transitions which are found to contribute significantly to the device external quantum efficiency. The high V(OC) reached in devices based on MDMO-PPV:4-CN-Ph-DTTzTz blends meets the expectations for such a donor:acceptor combination. However, thermal activation of charge carrier recombination occurs because of the weak driving force for charge transfer, as shown by time-dependent PIA measurements, and this is suggested as a cause for the observed low photovoltaic performance.

Newly formulated, protein quality-enhanced, extruded sorghum-, cowpea-, corn-, soya-, sugar- and oil-containing fortified-blended foods lead to adequate vitamin A and iron outcomes and improved growth compared with non-extruded CSB+ in rats.

PubMed

Delimont, Nicole M; Fiorentino, Nicole M; Opoku-Acheampong, Alexander B; Joseph, Michael V; Guo, Qingbin; Alavi, Sajid; Lindshield, Brian L

2017-01-01

Corn and soyabean micronutrient-fortified-blended foods (FBF) are commonly used for food aid. Sorghum and cowpeas have been suggested as alternative commodities because they are drought tolerant, can be grown in many localities, and are not genetically modified. Change in formulation of blends may improve protein quality, vitamin A and Fe availability of FBF. The primary objective of this study was to compare protein efficiency, Fe and vitamin A availability of newly formulated extruded sorghum-, cowpea-, soya- and corn-based FBF, along with a current, non-extruded United States Agency for International Development (USAID) corn and soya blend FBF (CSB+). A second objective was to compare protein efficiency of whey protein concentrate (WPC) and soya protein isolate (SPI) containing FBF to determine whether WPC inclusion improved outcomes. Eight groups of growing rats ( n 10) consumed two white and one red sorghum-cowpea (WSC1 + WPC, WSC2 + WPC, RSC + WPC), white sorghum-soya (WSS + WPC) and corn-soya (CSB14 + WPC) extruded WPC-containing FBF, an extruded white sorghum-cowpea with SPI (WSC1 + SPI), non-extruded CSB+, and American Institute of Nutrition (AIN)-93G, a weanling rat diet, for 4 weeks. There were no significant differences in protein efficiency, Fe or vitamin A outcomes between WPC FBF groups. The CSB+ group consumed significantly less food, gained significantly less weight, and had significantly lower energy efficiency, protein efficiency and length, compared with all other groups. Compared with WSC1 + WPC, the WSC1 + SPI FBF group had significantly lower energy efficiency, protein efficiency and weight gain. These results suggest that a variety of commodities can be used in the formulation of FBF, and that newly formulated extruded FBF are of better nutritional quality than non-extruded CSB+.

Well-to-Wheels Greenhouse Gas Emission Analysis of High-Octane Fuels with Ethanol Blending: Phase II Analysis with Refinery Investment Options

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

Han, Jeongwoo; Wang, Michael; Elgowainy, Amgad

Higher-octane gasoline can enable increases in an internal combustion engine’s energy efficiency and a vehicle’s fuel economy by allowing an increase in the engine compression ratio and/or by enabling downspeeding and downsizing. Producing high-octane fuel (HOF) with the current level of ethanol blending (E10) could increase the energy and greenhouse gas (GHG) emissions intensity of the fuel product from refinery operations. Alternatively, increasing the ethanol blending level in final gasoline products could be a promising solution to HOF production because of the high octane rating and potentially low blended Reid vapor pressure (RVP) of ethanol at 25% and higher ofmore » the ethanol blending level by volume. In our previous HOF well-to-wheels (WTW) report (the so-called phase I report of the HOF WTW analysis), we conducted WTW analysis of HOF with different ethanol blending levels (i.e., E10, E25, and E40) and a range of vehicle efficiency gains with detailed petroleum refinery linear programming (LP) modeling by Jacobs Consultancy and showed that the overall WTW GHG emission changes associated with HOFVs were dominated by the positive impact associated with vehicle efficiency gains and ethanol blending levels, while the refining operations to produce gasoline blendstock for oxygenate blending (BOB) for various HOF blend levels had a much smaller impact on WTW GHG emissions (Han et al. 2015). The scope of the previous phase I study, however, was limited to evaluating PADDs 2 and 3 operation changes with various HOF market share scenarios and ethanol blending levels. Also, the study used three typical configuration models of refineries (cracking, light coking, and heavy coking) in each PADD, which may not be representative of the aggregate response of all refineries in each PADD to various ethanol blending levels and HOF market scenarios. Lastly, the phase I study assumed no new refinery expansion in the existing refineries, which limited E10 HOF production to the volume achievable by the cracking refinery configuration. To be able to satisfy large market demands of E10 HOF, that study arbitrarily relaxed the RVP requirements by replacing reformulated gasoline (RFG) RVP requirement of 7 psi in summer with conventional gasoline (CG) RVP requirement of 9 psi in summer. To examine the response by all refineries in major refinery regions, this phase II of the HOF WTW analysis employed regionally aggregated refinery models for the following six regions: PADDs 1, 2, 3, 4, and 5 excluding California (CA) and CA separately. Using aggregate refinery models, this phase II study examined the impacts of ethanol blending and HOF market shares on the refinery operations in these six regions. Also, this study included refinery expansion to produce a pre-determined HOF volume with 10% ethanol blending. In particular, this study examined several refinery expansion options using refinery configuration models to investigate a practical refinery response to the increase in E10 HOF market demand.« less

Effect of hydrogen on ethanol-biodiesel blend on performance and emission characteristics of a direct injection diesel engine.

PubMed

Parthasarathy, M; Isaac JoshuaRamesh Lalvani, J; Dhinesh, B; Annamalai, K

2016-12-01

Environment issue is a principle driving force which has led to a considerable effort to develop and introduce alternative fuels for transportation. India has large potential for production of biofuels like biodiesel from vegetable seeds. Use of biodiesel namely, tamanu methyl ester (TME) in unmodified diesel engines leads to low thermal Efficiency and high smoke emission. To encounter this problem hydrogen was inducted by a port fueled injection system. Hydrogen is considered to be low polluting fuel and is the most promising among alternative fuel. Its clean burning characteristic and better performance attract more interest compared to other fuels. It was more active in reducing smoke emission in biodiesel. A main drawback with hydrogen fuel is the increased NO x emission. To reduce NO x emission, TME-ethanol blends were used in various proportions. After a keen study, it was observed that ethanol can be blended with biodiesel up to 30% in unmodified diesel engine. The present work deals with the experimental study of performance and emission characteristic of the DI diesel engine using hydrogen and TME-ethanol blends. Hydrogen and TME-ethanol blend was used to improve the brake thermal efficiency and reduction in CO, NO x and smoke emissions. Copyright © 2015 Elsevier Inc. All rights reserved.

Effect of anhydrous ethanol/gasoline blends on performance and exhaust emissions of spark-ignited non-road engines.

PubMed

Ribeiro, Camilo Bastos; Martins, Kelly Geronazzo; Gueri, Matheus Vitor Diniz; Pavanello, Guilherme Pozzobom; Schirmer, Waldir Nagel

2018-06-12

Ethanol is a renewable fuel and it is considered an alternative to gasoline in Otto-cycle engines. The present study evaluated the behavior of exhaustion gas carbon monoxide (CO) and total hydrocarbons (THC) according to the levels of anhydrous ethyl alcohol (AEA) added to gasoline in different proportions (E0, E10, E20, E27, that is, pure gasoline and its blends with AEA at 10, 20, and 27% v/v) in the use of non-road single cylinder engines of different powers (13 and 6.5 hp), to the loads applied to engine-generators and the air-fuel ratio (A/F) admitted to the engine cylinders. Also, the performance of engine-generators was verified in terms of mass, specific and energetic consumption and efficiency of the evaluated systems for the same blends and loads. The results showed that an increase in the AEA content in the blend resulted in significant drops in CO and THC concentrations for both engine-generators, while fuel consumption showed a slight upward trend; the increases in applied loads resulted in an increase in CO and THC concentrations and fuel consumption. In general, a higher AEA content (oxygenated) in the blends had a greater effect on gaseous emissions compared to the effect on consumption and system efficiency.

Anaerobic Biodegradation of Soybean Biodiesel and Diesel ...

EPA Pesticide Factsheets

Biotransformation of soybean biodiesel and the inhibitory effect of petrodiesel were studied under methanogenic conditions. Biodiesel removal efficiency of more than 95% was achieved in a chemostat with influent biodiesel concentrations up to 2.45 g/L. The kinetics of anaerobic biodegradation of soybean biodiesel B100 (biodiesel only) with different petrodiesel loads were studied using biomass pre-acclimated to B100 and B80 (80% biodiesel and 20 petrodiesel). The results indicated that the biodiesel fraction of the blend could be effectively biodegraded, whereas petrodiesel was not biodegraded at all under methanogenic conditions. The presence of petrodiesel in blends with biodiesel had a greater inhibitory effect on the rate of biodegradation than the biodegradation efficiency (defined as the efficiency of methane production). Both the biodegradation rate coefficient and the methane production efficiency increased almost linearly with the increasing fraction of biodiesel. With the increasing fraction of petrodiesel, the biodegradation rate and efficiency were correlated with the concentration of soluble FAMEs in the water. The objective of this study was to investigate the anaerobic biodegradation of soybean biodiesel blends under methanogenic conditions. Biological methane potential (BMP) tests were conducted in serum bottles to determine the anaerobic biodegradation kinetics of biodiesel in the absence and presence of different concentrations of petrod

Microencapsulation of Nigella sativa oleoresin by spray drying for food and nutraceutical applications.

PubMed

Edris, Amr E; Kalemba, Danuta; Adamiec, Janusz; Piątkowski, Marcin

2016-08-01

Oleoresin of Nigella sativa L. (Black cumin) was obtained from the seeds using hexane extraction at room temperature. The oleoresin was emulsified in an aqueous solution containing gum Arabic/maltodextrin (1:1 w/w) and then encapsulated in powder form by spray drying. The characteristics of the obtained powder including moisture content, bulk density, wettability, morphology, encapsulation efficiency were evaluated. The effect of the spray drying on the chemical composition of the volatile oil fraction of N. sativa oleoresin was also evaluated using gas chromatographic-mass spectroscopic analysis. Results indicated that the encapsulation efficiency of the whole oleoresin in the powder can range from 84.2±1.5% to 96.2±0.2% depending on the conditions of extracting the surface oil from the powder. On the other hand the encapsulation efficiency of the volatile oil fraction was 86.2% ±4.7. The formulated N. sativa L. oleoresin powder can be used in the fortification of processed food and nutraceuticals. Copyright © 2016 Elsevier Ltd. All rights reserved.

Needle-free injection of insulin powder: delivery efficiency and skin irritation assessment.

PubMed

Li, Chun-yu; Wang, Zhe-wei; Tu, Can; Wang, Jia-bo; Jiang, Bing-qian; Li, Qi; Zeng, Ling-na; Ma, Zhi-jie; Zhang, Ping; Zhao, Yan-ling; Zhang, Ya-ming; Yan, Dan; Tan, Rui; Xiao, Xiao-he

2014-10-01

Insulin is widely used in treating diabetes, but still needs to be administered by needle injection. This study investigated a new needle-free approach for insulin delivery. A portable powder needleless injection (PNI) device with an automatic mechanical unit was designed. Its efficiency in delivering insulin was evaluated in alloxan-induced diabetic rabbits. The skin irritation caused by the device was investigated and the results were analyzed in relation to aerodynamic parameters. Inorganic salt-carried insulin powders had hypoglycemic effects, while raw insulin powders were not effective when delivered by PNI, indicating that salt carriers play an important role in the delivery of insulin via PNI. The relative delivery efficiency of phosphate-carried insulin powder using the PNI device was 72.25%. A safety assessment test showed that three key factors (gas pressure, cylinder volume, and nozzle distance) were related to the amount of skin irritation caused by the PNI device. Optimized injection conditions caused minimal skin lesions and are safe to use in practice. The results suggest that PNI has promising prospects as a novel technology for delivering insulin and other biological drugs.

Needle-free injection of insulin powder: delivery efficiency and skin irritation assessment*

PubMed Central

Li, Chun-yu; Wang, Zhe-wei; Tu, Can; Wang, Jia-bo; Jiang, Bing-qian; Li, Qi; Zeng, Ling-na; Ma, Zhi-jie; Zhang, Ping; Zhao, Yan-ling; Zhang, Ya-ming; Yan, Dan; Tan, Rui; Xiao, Xiao-he

2014-01-01

Insulin is widely used in treating diabetes, but still needs to be administered by needle injection. This study investigated a new needle-free approach for insulin delivery. A portable powder needleless injection (PNI) device with an automatic mechanical unit was designed. Its efficiency in delivering insulin was evaluated in alloxan-induced diabetic rabbits. The skin irritation caused by the device was investigated and the results were analyzed in relation to aerodynamic parameters. Inorganic salt-carried insulin powders had hypoglycemic effects, while raw insulin powders were not effective when delivered by PNI, indicating that salt carriers play an important role in the delivery of insulin via PNI. The relative delivery efficiency of phosphate-carried insulin powder using the PNI device was 72.25%. A safety assessment test showed that three key factors (gas pressure, cylinder volume, and nozzle distance) were related to the amount of skin irritation caused by the PNI device. Optimized injection conditions caused minimal skin lesions and are safe to use in practice. The results suggest that PNI has promising prospects as a novel technology for delivering insulin and other biological drugs. PMID:25294378

Remediation of Ni(2+)-contaminated water using iron powder and steel manufacturing byproducts.

PubMed

Jin, Jian; Zhao, Wei-Rong; Xu, Xin-Hua; Hao, Zhi-Wei; Liu, Yong; He, Ping; Zhou, Mi

2006-01-01

Steel manufacturing byproducts and commercial iron powders were tested in the treatment of Ni(2+)-contaminated water. Ni2+ is a priority pollutant of some soils and groundwater. The use of zero-valent iron, which can reduce Ni2+ to its neural form appears to be an alternative approach for the remediation of Ni(2+)-contaminated sites. Our experimental data show that the removal efficiencies of Ni2+ were 95.15% and 94.68% at a metal to solution ratio of 20 g/L for commercial iron powders and the steel manufacturing byproducts in 60 min at room temperature, respectively. The removal efficiency reached 98.20% when the metal to solution ratio was 40 g/L for commercial iron powders. Furthermore, we found that the removal efficiency was also largely affected by other factors such as the pHs of the treated water, the length of time for the metal to be in contact with the Ni(2+)-contaminated water, initial concentrations of metal solutions, particle sizes and the amount of iron powders. Surprisingly, the reaction temperature appeared to have little effect on the removal efficiency. Our study opens the way to further optimize the reaction conditions of in situ remediation of Ni2+ or other heavy metals on contaminated sites.

Dry powder inhaler performance of spray dried mannitol with tailored surface morphologies as carrier and salbutamol sulphate.

PubMed

Mönckedieck, M; Kamplade, J; Fakner, P; Urbanetz, N A; Walzel, P; Steckel, H; Scherließ, R

2017-05-30

Nowadays, dry powder inhalation as applied in the therapy of pulmonary diseases is known as a very effective route of drug delivery to the lungs. Here, the system of coarse carrier and fine drug particles attached to the carrier surface has successfully been applied to overcome the cohesiveness of small drug particles. Particle properties of both carrier and drug are known to affect drug dispersion as has widely been discussed for lactose monohydrate and various drugs. This study utilises particle-engineered mannitol as an alternative carrier to discover the effect of mannitol carrier particle properties like particle shape, surface roughness, flowability or particle size on aerodynamic performance during inhalation. Spray drying as a technique to accurately control those properties was chosen for the generation of carrier sizes between 50 and 80 μm and different morphologies and therefore various carrier flowabilities. A set of these carriers has then been blended with different spray dried and jet-milled qualities of salbutamol sulphate as model drug to examine the influence of carrier particle properties on aerodynamic behaviour and at the same time to cover the effect of drug particle properties on particle-particle interactions. This experimental setup allowed a general view on how drug and carrier properties affect the Fine Particle Fraction (FPF) as indicator for inhalation performance and gave the first study to distinguish between mannitol carrier particle shape and surface roughness. Further it was possible to relate carrier particle size and shape to drug accumulation and detachment mechanisms during inhalation as size and shape had the main influence on drug detachment. The addition of jet-milled mannitol fines provided an initial insight into the improving effect of ternary powder blends as has been intensively studied for lactose monohydrate but not for mannitol yet. Copyright © 2017 Elsevier B.V. All rights reserved.

Formulation and in vitro evaluation of theophylline matrix tablets prepared by direct compression: Effect of polymer blends

PubMed Central

El-Bagory, Ibrahim; Barakat, Nahla; Ibrahim, Mohamed A.; El-Enazi, Fouza

2011-01-01

The deformation mechanism of pharmaceutical powders, used in formulating directly compressed matrix tablets, affects the characteristics of the formed tablets. Three polymers of different deformation mechanisms were tested for their impact on theophylline directly compressed tablets namely Kollidon SR (KL SR, plastic deformation), Ethylcellulose (EC, elastic deformation) and Carnauba wax (CW, brittle deformation) at different compression forces. However, tablets based mainly on KL SR, the plastically deformed polymer (TN1) exhibited the highest hardness values compared to the other formulae which are based on either blends of KL SR with CW, the very brittle deformed polymer. The upper detected force for TN formulae and the lower punch force were found to dependent mainly on the powder deformation. This difference is attributed to the work done during the compression phase as well as the work lost during the decompression phase. Furthermore, the release profiles of TN from formulae TN2 and TN4 that are based on the composition (2KL SR:1EC) and (1KL SR:2EC), respectively, were consistent with different deformation mechanisms of KL SR and EC and on the physicochemical properties like the water absorptive capacity of EC. Upon increasing the weight ratio of KL SR (TN2), the release rate was greatly retarded (39.4%, 37.1%, 35.0% and 33.6% released after 8 h at 5, 10, 15 and 20 kN. PMID:24115902

Evaluation of rheological, bioactives and baking characteristics of mango ginger (curcuma amada) enriched soup sticks.

PubMed

Crassina, K; Sudha, M L

2015-09-01

Wheat flour was replaced with mango ginger powder (MGP) at 0, 5, 10 and 15 %. Influence of MGP on rheological and baking characteristics was studied. Farinograph was used to study the mixing profile of wheat flour-MGP blend. Pasting profile of the blends namely gelatinization and retrogradation were carried out using micro-visco-amylograph. Test baking was done to obtain the optimum level of replacement and processing conditions. Sensory attributes consisting texture, taste, overall quality and breaking strength were assessed. Nutritional characterization of the soup sticks in terms of protein and starch in vitro digestibility, dietary fiber, minerals, polyphenols and antioxidant activity were determined using standard methods. With the increasing levels of MGP from 0 to 15 %, the farinograph water absorption increased from 60 to 66.7 %. A marginal increase in the gelatinization temperature from 65.4 to 66.2 °C was observed. Retrogradation of gelatinized starch granules decreased with the addition of MGP. The results indicated that the soup stick with 10 % MG had acceptable sensory attributes. The soup stick showed further improvement in terms of texture and breaking strength with the addition of gluten powder, potassium bromate and glycerol monostearate. The total dietary fiber and antioxidant activity of the soup sticks having 10 % MGP increased from 3.31 to 8.64 % and 26.83 to 48.06 % respectively as compared to the control soup sticks. MGP in soup sticks improved the nutritional profile.

Tableting properties of silica aerogel and other silicates.

PubMed

Hentzschel, C M; Alnaief, M; Smirnova, I; Sakmann, A; Leopold, C S

2012-04-01

In solid oral dosage forms silicates are commonly used as glidants in low concentration. However, due to their large specific surface area, silicates may also be used as carrier materials for drugs. Moreover, silicates allow amorphisation of drugs by co-grinding or processing with supercritical fluids. The aim of this study was to investigate the physical and the tableting properties of Silica Aerogel (special type of silica with an extremely large specific surface area), Neusilin(®) US2 (magnesium aluminometasilicate), Florite(®) (calcium silicate) and Aerosil(®) 200 (colloidal silica). Powder blends of Avicel(®) PH102 (microcrystalline cellulose) and different amounts of the respective silicate were compacted and analyzed for their tabletability (tensile strength vs. compaction pressure) as well as their Heckel plot. With Neusilin(®) the tabletability appeared to be independent of the silicate concentration, whereas with Florite(®) an increasing silicate concentration led to a higher tensile strength. In contrast, the addition of Silica Aerogel and Aerosil(®) resulted in a decrease of the tensile strength. With Aerosil(®) a maximum tolerable concentration of 20% [w/w] was determined. Plastic deformation of all powder blends decreased with increasing silicate concentration. This effect was most pronounced with Aerosil(®) and least with Florite(®). Tablets with acceptable tensile strength were obtained with all plain silicates except for Aerosil(®). Therefore, these silicates may be used in tablet formulations, e.g. as carrier materials for liquid or amorphous drugs.

Influence of process parameters on content uniformity of a low dose active pharmaceutical ingredient in a tablet formulation according to GMP.

PubMed

Muselík, Jan; Franc, Aleš; Doležel, Petr; Goněc, Roman; Krondlová, Anna; Lukášová, Ivana

2014-09-01

The article describes the development and production of tablets using direct compression of powder mixtures. The aim was to describe the impact of filler particle size and the time of lubricant addition during mixing on content uniformity according to the Good Manufacturing Practice (GMP) process validation requirements. Processes are regulated by complex directives, forcing the producers to validate, using sophisticated methods, the content uniformity of intermediates as well as final products. Cutting down of production time and material, shortening of analyses, and fast and reliable statistic evaluation of results can reduce the final price without affecting product quality. The manufacturing process of directly compressed tablets containing the low dose active pharmaceutical ingredient (API) warfarin, with content uniformity passing validation criteria, is used as a model example. Statistic methods have proved that the manufacturing process is reproducible. Methods suitable for elucidation of various properties of the final blend, e.g., measurement of electrostatic charge by Faraday pail and evaluation of mutual influences of researched variables by partial least square (PLS) regression, were used. Using these methods, it was proved that the filler with higher particle size increased the content uniformity of both blends and the ensuing tablets. Addition of the lubricant, magnesium stearate, during the blending process improved the content uniformity of blends containing the filler with larger particles. This seems to be caused by reduced sampling error due to the suppression of electrostatic charge.

Physicochemical characterization and mechanisms of release of theophylline from melt-extruded dosage forms based on a methacrylic acid copolymer.

PubMed

Young, Christopher R; Dietzsch, Caroline; Cerea, Matteo; Farrell, Thomas; Fegely, Kurt A; Rajabi-Siahboomi, Ali; McGinity, James W

2005-09-14

The purpose of the current study was to investigate the physicochemical properties of melt-extruded dosage forms based on Acryl-EZE and to determine the influence of gelling agents on the mechanisms and kinetics of drug release from thermally processed matrices. Acryl-EZE is a pre-mixed excipient blend based on a methacrylic acid copolymer that is optimized for film-coating applications. Powder blends containing theophylline, Acryl-EZE, triethyl citrate and an optional gelling agent, Methocel K4M Premium (hydroxypropyl methylcellulose, HPMC, hypromellose 2208) or Carbopol 974P (carbomer), were thermally processed using a Randcastle single-screw extruder. The physical and chemical stability of materials during processing was determined using thermal gravimetric analysis and HPLC. The mechanism of drug release was determined using the Korsmeyer-Peppas model and the hydration and erosion of tablets during the dissolution studies were investigated. The excipient blends were physically and chemically stable during processing, and the resulting dosage forms exhibited pH-dependent dissolution properties. Extrusion of blends containing HPMC or carbomer changed the mechanism and kinetics of drug release from the thermally processed dosage forms. At concentrations of 5% or below, carbomer was more effective than HPMC at extending the duration of theophylline release from matrix tablets. Furthermore, carbomer containing tablets were stable upon storage for 3 months at 40 degrees C/75% RH. Thus, hot-melt extrusion was an effective process for the preparation of controlled release matrix systems based on Acryl-EZE.

A Systematic Approach to Faculty Development--Capability Improvement for Blended Learning

ERIC Educational Resources Information Center

Badawood, Ashraf; Steenkamp, Annette Lerine; Al-Werfalli, Daw

2013-01-01

Blended learning (BL) provides an efficient and effective instructional experience. However, adopting a BL approach poses some challenges to faculty; the most important obstacle found in this research is faculty's lack of knowledge regarding the use of technology in their teaching. This challenge prompted the research project focused on improving…

Supporting Blended-Learning: Tool Requirements and Solutions with OWLish

ERIC Educational Resources Information Center

Álvarez, Ainhoa; Martín, Maite; Fernández-Castro, Isabel; Urretavizcaya, Maite

2016-01-01

Currently, most of the educational approaches applied to higher education combine face-to-face (F2F) and computer-mediated instruction in a Blended-Learning (B-Learning) approach. One of the main challenges of these approaches is fully integrating the traditional brick-and-mortar classes with online learning environments in an efficient and…

Experimental studies on natural aspirated diesel engine fuelled with corn seed oil methyl ester as a bio-diesel.

NASA Astrophysics Data System (ADS)

Rama Krishna Reddy, E.; Dhana Raju, V.

2018-03-01

This paper evaluates the possibilities of using corn seed oil methyl ester as a fuel for compression ignition engines. The biodiesels are contained high oxygen content, and high Cetane number, due to this properties efficiency of biodiesel is higher than diesel fuel. The experiments were conducted with different biodiesel blends of (B10, B15, B20 and B25) corn seed oil on single cylinder four stroke natural aspirated diesel engines. Performance parameters and exhaust emissions are investigated in this experimental with the blends of the corn seed oil methyl ester and diesel fuel. The test results showed that the bio-diesel blends gives improved results for brake thermal efficiency and specific fuel consumption when compared with the diesel fuel. The emissions of corn seed methyl esters follow the same trend of diesel but the smoke opacity was reduces for all blends. From the investigation, corn seed methyl ester is also having the properties similar to diesel fuel; it is biodegradable and renewable fuel, so it will be used as an alternative for diesel fuel.

Study of a ternary blend system for bulk heterojunction thin film solar cells

NASA Astrophysics Data System (ADS)

Ahmad, Zubair; Touati, Farid; Shakoor, R. A.; Al-Thani, N. J.

2016-08-01

In this research, we report a bulk heterojunction (BHJ) solar cell consisting of a ternary blend system. Poly(3-hexylthiophene) P3HT is used as a donor and [6,6]-phenyl C61-butyric acid methylester (PCBM) plays the role of acceptor whereas vanadyl 2,9,16,23-tetraphenoxy-29H, 31H-phthalocyanine (VOPcPhO) is selected as an ambipolar transport material. The materials are selected and assembled in such a fashion that the generated charge carriers could efficiently be transported rightwards within the blend. The organic BHJ solar cells consist of ITO/PEDOT:PSS/ternary BHJ blend/Al structure. The power conversion efficiencies of the ITO/ PEDOT:PSS/P3HT:PCBM/Al and ITO/PEDOT:PSS/ P3HT:PCBM:VOPcPhO/Al solar cells are found to be 2.3% and 3.4%, respectively. This publication was made possible by PDRA (Grant No. PDRA1-0117-14109) from the Qatar National Research Fund (a member of Qatar Foundation). The findings achieved herein are solely the responsibility of the authors.

Optimized pulmonary gene transfection in mice by spray-freeze dried powder inhalation.

PubMed

Mohri, Kohta; Okuda, Tomoyuki; Mori, Asami; Danjo, Kazumi; Okamoto, Hirokazu

2010-06-01

Spray-freeze drying (SFD) is an attractive technique to prepare highly porous dry powders for inhalation. However, there have been few reports of its application to dry powder inhalers (DPIs). Therefore, in this study, we prepared dry plasmid DNA (pDNA) powders with different molecular ratios of chitosan to pDNA (N/P ratios) by SFD. All the pDNA powders were spherical and highly porous, with particles approximately 20-40microm in geometric diameter. The morphology changed little with the alteration of the N/P ratio. On electrophoresis, a band of linear pDNA was detected in the preparation without chitosan, suggesting the destabilization of pDNA through SFD. However, the addition of chitosan protected pDNA from destabilization. Moreover, the pDNA powders were evaluated for pulmonary gene transfection efficiency using an in vivo dual imaging technique for gene DPIs developed previously. Maximum gene expression was observed at 9-12h following pulmonary administration of the powders into mice. The powder with the N/P ratio of 10 had the highest gene transfection efficiency. A higher affinity of chitosan for pDNA and a smaller (approximately 100nm) pDNA/chitosan complex (N/Pf10) were found at pH 6.5 (in lung) than at pH 7.4 (in physiological conditions), suggesting that the effective compaction of pDNA by chitosan at the N/P ratio of 10 at pH 6.5 contributes to the gene transfection efficiency in the lung. These results suggest inhalable dry pDNA powders with chitosan prepared by SFD to be a suitable formulation for pulmonary gene therapy. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Improved Algorithms for Blending Dam Releases to Meet Downstream Water-Temperature Targets in the CE-QUAL-W2 Water-Quality Model

NASA Astrophysics Data System (ADS)

Rounds, S. A.; Buccola, N. L.

2014-12-01

The two-dimensional (longitudinal, vertical) water-quality model CE-QUAL-W2, version 3.7, was enhanced with new features to help dam operators and managers efficiently explore and optimize potential solutions for temperature management downstream of thermally stratified reservoirs. Such temperature management often is accomplished by blending releases from multiple dam outlets that access water of different temperatures at different depths in the reservoir. The original blending algorithm in this version of the model was limited to mixing releases from two outlets at a time, and few constraints could be imposed. The new enhanced blending algorithm allows the user to (1) specify a time-series of target release temperatures, (2) designate from 2 to 10 floating or fixed-elevation outlets for blending, (3) impose maximum head constraints as well as minimum and maximum flow constraints for any blended outlet, and (4) set a priority designation for each outlet that allows the model to choose which outlets to use and how to balance releases among them. The modified model was tested against a previously calibrated model of Detroit Lake on the North Santiam River in northwestern Oregon, and the results compared well. The enhanced model code is being used to evaluate operational and structural scenarios at multiple dam/reservoir systems in the Willamette River basin in Oregon, where downstream temperature management for endangered fish is a high priority for resource managers and dam operators. These updates to the CE-QUAL-W2 blending algorithm allow scenarios involving complicated dam operations and/or hypothetical outlet structures to be evaluated more efficiently with the model, with decreased need for multiple/iterative model runs or preprocessing of model inputs to fully characterize the operational constraints.

Polyethersulfone - barium chloride blend ultrafiltration membranes for dye removal studies

NASA Astrophysics Data System (ADS)

Rambabu, K.; Srivatsan, N.; Gurumoorthy, Anand V. P.

2017-11-01

A series of Polyethersulfone (PES) - barium chloride (BaCl2) blend ultra filtration membrane was developed by varying the BaCl2 concentration in the dope solution. Prepared membranes were subjected to membrane characterization and their performance was studied through dye rejection tests. Morphological studies through SEM and AFM showed that the composite membranes exhibited differences in morphologies, porosities and properties due to the BaCl2 addition as compared with pristine PES membrane. Addition of the inorganic modifier enhanced the hydrophilicity and water permeability of the blend membrane system. Polymer enhanced ultrafiltration of dye solutions showed that the proposed blend system had better performance in terms of flux and rejection efficiency than the pure polymer membrane. The performance of the 2 wt% BaCl2 blend membrane was more promising for application to real time dye wastewater studies.

Porous-electrode preparation method

DOEpatents

Arons, R.M.; Dusek, J.T.

1981-09-17

A porous sintered plaque is provided with a bimodal porosity that is especially well suited for use as an electrode within a molten carbonate fuel cell. The coarse porosity is sufficient for admitting gases into contact with the reaction surfaces while the fine porosity is wetted with and retains molten electrolyte on the reaction sites. The electrode structure is prepared by providing a very fine powder such as nickel oxide and blending the powder with a suitable decomposable binder to form a solid mass. The mass is comminuted into agglomerate size particles substantially larger than the fine oxide particles and formed into a cohesive compact for subsequent sintering. Sintering is carried out at sufficient conditions to bind the agglomerates together into a porous structure having both coarse and fine porosity. Where lithiated nickel oxide cathodes are prepared, the sintering conditions can be moderate enough to retain substantial quantities of lithium within the electrode for adequate conductivity.

Porous electrode preparation method

DOEpatents

Arons, Richard M.; Dusek, Joseph T.

1983-01-01

A porous sintered plaque is provided with a bimodal porosity that is especially well suited for use as an electrode within a molten carbonate fuel cell. The coarse porosity is sufficient for admitting gases into contact with the reaction surfaces while the fine porosity is wetted with and retains molten electrolyte on the reaction sites. The electrode structure is prepared by providing a very fine powder of such as nickel oxide and blending the powder with a suitable decomposable binder to form a solid mass. The mass is comminuted into agglomerate size particles substantially larger than the fine oxide particles and formed into a cohesive compact for subsequent sintering. Sintering is carried out at sufficient conditions to bind the agglomerates together into a porous structure having both coarse and fine porosity. Where lithiated nickel oxide cathodes are prepared, the sintering conditions can be moderate enough to retain substantial quantities of lithium within the electrode for adequate conductivity.

Ternary blends containing demercurated lighting phosphor and MSWI fly ash as high-performance binders for stabilizing and recycling electroplating sludge.

PubMed

Huang, Wu-Jang; Wu, Chia-Teng; Wu, Chang-En; Hsieh, Lin-Huey; Li, Chang-Chien; Lain, Chi-Yuan; Chu, Wei

2008-08-15

This paper describes the solidification and stabilization of electroplating sludge treated with a high-performance binder made from portland type-I cement, municipal solid waste incineration fly ash, and lighting phosphor powder (called as cement-fly ash-phosphor binder, CFP). The highest 28-day unconfined compressive strength of the CFP-treated paste was 816 kg/cm(2) at a ratio of cement to fly ash to lighting phosphor powder of 90:5:5; the strength of this composition also fulfilled the requirement of a high-strength concrete (>460 kg/cm(2) at 28 days). The CFP-stabilized sludge paste samples passed the Taiwanese EPA toxicity characteristic leaching procedure test and, therefore, could be used either as a building material or as a controlled low-strength material, depending on the sludge-to-CFP binder ratio.

Porous electrode preparation method

DOEpatents

Arons, R.M.; Dusek, J.T.

1983-10-18

A porous sintered plaque is provided with a bimodal porosity that is especially well suited for use as an electrode within a molten carbonate fuel cell. The coarse porosity is sufficient for admitting gases into contact with the reaction surfaces while the fine porosity is wetted with and retains molten electrolyte on the reaction sites. The electrode structure is prepared by providing a very fine powder of such as nickel oxide and blending the powder with a suitable decomposable binder to form a solid mass. The mass is comminuted into agglomerate size particles substantially larger than the fine oxide particles and formed into a cohesive compact for subsequent sintering. Sintering is carried out at sufficient conditions to bind the agglomerates together into a porous structure having both coarse and fine porosity. Where lithiated nickel oxide cathodes are prepared, the sintering conditions can be moderate enough to retain substantial quantities of lithium within the electrode for adequate conductivity. 2 figs.

Parts per Million Powder X-ray Diffraction

DOE PAGES

Newman, Justin A.; Schmitt, Paul D.; Toth, Scott J.; ...

2015-10-14

Here in this paper we demonstrate the use of second harmonic generation (SHG) microscopy-guided synchrotron powder X-ray diffraction (PXRD) for the detection of trace crystalline active pharmaceutical ingredients in a common polymer blend. The combined instrument is capable of detecting 100 ppm crystalline ritonavir in an amorphous hydroxypropyl methylcellulose matrix with a high signal-to-noise ratio (>5000). The high spatial resolution afforded by SHG microscopy allows for the use of a minibeam collimator to reduce the total volume of material probed by synchrotron PXRD. The reduction in probed volume results in reduced background from amorphous material. The ability to detect lowmore » crystalline loading has the potential to improve measurements in the formulation pipeline for pharmaceutical solid dispersions, for which even trace quantities of crystalline active ingredients can negatively impact the stability and bioavailability of the final drug product.« less

Exploring the Photovoltaic Performance of All-Inorganic Ag2PbI4/PbI2 Blends.

PubMed

Frolova, Lyubov A; Anokhin, Denis V; Piryazev, Alexey A; Luchkin, Sergey Yu; Dremova, Nadezhda N; Troshin, Pavel A

2017-04-06

We present an all-inorganic photoactive material composed of Ag 2 PbI 4 and PbI 2 , which shows unexpectedly good photovoltaic performance in planar junction solar cells delivering external quantum efficiencies of ∼60% and light power conversion efficiencies of ∼3.9%. The revealed characteristics are among the best reported to date for metal halides with nonperovskite crystal structure. Most importantly, the obtained results suggest a possibility of reaching high photovoltaic efficiencies for binary and, probably, also ternary blends of different inorganic semiconductor materials. This approach, resembling the bulk heterojunction concept guiding the development of organic photovoltaics for two decades, opens wide opportunities for rational design of novel inorganic and hybrid materials for efficient and sustainable photovoltaic technologies.

Enhancement of Photovoltaic Performance by Utilizing Readily Accessible Hole Transporting Layer of Vanadium(V) Oxide Hydrate in a Polymer-Fullerene Blend Solar Cell.

PubMed

Jiang, Youyu; Xiao, Shengqiang; Xu, Biao; Zhan, Chun; Mai, Liqiang; Lu, Xinhui; You, Wei

2016-05-11

Herein, a successful application of V2O5·nH2O film as hole transporting layer (HTL) instead of PSS in polymer solar cells is demonstrated. The V2O5·nH2O layer was spin-coated from V2O5·nH2O sol made from melting-quenching sol-gel method by directly using vanadium oxide powder, which is readily accessible and cost-effective. V2O5·nH2O (n ≈ 1) HTL is found to have comparable work function and smooth surface to that of PSS. For the solar cell containing V2O5·nH2O HTL and the active layer of the blend of a novel polymer donor (PBDSe-DT2PyT) and the acceptor of PC71BM, the PCE was significantly improved to 5.87% with a 30% increase over 4.55% attained with PSS HTL. Incorporation of V2O5·nH2O as HTL in the polymer solar cell was found to enhance the crystallinity of the active layer, electron-blocking at the anode and the light-harvest in the wavelength range of 400-550 nm in the cell. V2O5·nH2O HTL improves the charge generation and collection and suppress the charge recombination within the PBDSe-DT2PyT:PC71BM solar cell, leading to a simultaneous enhancement in Voc, Jsc, and FF. The V2O5·nH2O HTL proposed in this work is envisioned to be of great potential to fabricate highly efficient PSCs with low-cost and massive production.

Gasohol Quality Control for Real Time Applications by Means of a Multimode Interference Fiber Sensor

PubMed Central

Rodríguez Rodríguez, Adolfo J.; Baldovino-Pantaleón, Oscar; Domínguez Cruz, Rene F.; Zamarreño, Carlos R.; Matías, Ignacio R.; May-Arrioja, Daniel A.

2014-01-01

In this work we demonstrate efficient quality control of a variety of gasoline and ethanol (gasohol) blends using a multimode interference (MMI) fiber sensor. The operational principle relies on the fact that the addition of ethanol to the gasohol blend reduces the refractive index (RI) of the gasoline. Since MMI sensors are capable of detecting small RI changes, the ethanol content of the gasohol blend is easily determined by tracking the MMI peak wavelength response. Gasohol blends with ethanol contents ranging from 0% to 50% has been clearly identified using this device, which provides a linear response with a maximum sensitivity of 0.270 nm/% EtOH. The sensor can also distinguish when water incorporated in the blend has exceeded the maximum volume tolerated by the gasohol blend, which is responsible for phase separation of the ethanol and gasoline and could cause serious engine failures. Since the MMI sensor is straightforward to fabricate and does not require any special coating it is a cost effective solution for real time and in-situ monitoring of the quality of gasohol blends. PMID:25256111

Forming a single layer of a composite powder based on the Ti-Nb system via selective laser melting (SLM)

NASA Astrophysics Data System (ADS)

Saprykin, A. A.; Sharkeev, Yu P.; Ibragimov, E. A.; Babakova, E. V.; Dudikhin, D. V.

2016-07-01

Alloys based on the titanium-niobium system are widely used in implant production. It is conditional, first of all, on the low modulus of elasticity and bio-inert properties of an alloy. These alloys are especially important for tooth replacement and orthopedic surgery. At present alloys based on the titanium-niobium system are produced mainly using conventional metallurgical methods. The further subtractive manufacturing an end product results in a lot of wastes, increasing, therefore, its cost. The alternative of these processes is additive manufacturing. Selective laser melting is a technology, which makes it possible to synthesize products of metal powders and their blends. The point of this technology is laser melting a layer of a powdered material; then a sintered layer is coated with the next layer of powder etc. Complex products and working prototypes are made on the base of this technology. The authors of this paper address to the issue of applying selective laser melting in order to synthesize a binary alloy of a composite powder based on the titanium-niobium system. A set of 10x10 mm samples is made in various process conditions. The samples are made by an experimental selective laser synthesis machine «VARISKAF-100MB». The machine provides adjustment of the following process variables: laser emission power, scanning rate and pitch, temperature of powder pre-heating, thickness of the layer to be sprinkled, and diameter of laser spot focusing. All samples are made in the preliminary vacuumized shielding atmosphere of argon. The porosity and thickness of the sintered layer related to the laser emission power are shown at various scanning rates. It is revealed that scanning rate and laser emission power are adjustable process variables, having the greatest effect on forming the sintered layer.

Polymer quenched prealloyed metal powder

DOEpatents

Hajaligol, Mohammad R.; Fleischhauer, Grier; German, Randall M.

2001-01-01

A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3 % Cu. The process includes forming a non-densified metal sheet by consolidating a powder having an intermetallic alloy composition such as by roll compaction, tape casting or plasma spraying, forming a cold rolled sheet by cold rolling the non-densified metal sheet so as to increase the density and reduce the thickness thereof and annealing the cold rolled sheet. The powder can be a water, polymer or gas atomized powder which is subjecting to sieving and/or blending with a binder prior to the consolidation step. After the consolidation step, the sheet can be partially sintered. The cold rolling and/or annealing steps can be repeated to achieve the desired sheet thickness and properties. The annealing can be carried out in a vacuum furnace with a vacuum or inert atmosphere. During final annealing, the cold rolled sheet recrystallizes to an average grain size of about 10 to 30 .mu.m. Final stress relief annealing can be carried out in the B2 phase temperature range.

Method of manufacturing aluminide sheet by thermomechanical processing of aluminide powders

DOEpatents

Hajaligol, Mohammad R.; Scorey, Clive; Sikka, Vinod K.; Deevi, Seetharama C.; Fleishhauer, Grier; Lilly, Jr., A. Clifton; German, Randall M.

2003-12-09

A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3% Cu. The process includes forming a non-densified metal sheet by consolidating a powder having an intermetallic alloy composition such as by roll compaction, tape casting or plasma spraying, forming a cold rolled sheet by cold rolling the non-densified metal sheet so as to increase the density and reduce the thickness thereof and annealing the cold rolled sheet. The powder can be a water, polymer or gas atomized powder which is subjecting to sieving and/or blending with a binder prior to the consolidation step. After the consolidation step, the sheet can be partially sintered. The cold rolling and/or annealing steps can be repeated to achieve the desired sheet thickness and properties. The annealing can be carried out in a vacuum furnace with a vacuum or inert atmosphere. During final annealing, the cold rolled sheet recrystallizes to an average grain size of about 10 to 30 .mu.m. Final stress relief annealing can be carried out in the B2 phase temperature range.

Method of manufacturing aluminide sheet by thermomechanical processing of aluminide powders

DOEpatents

Hajaligol, Mohammad R.; Scorey, Clive; Sikka, Vinod K.; Deevi, Seetharama C.; Fleischhauer, Grier; Lilly, Jr., A. Clifton; German, Randall M.

2000-01-01

A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr.ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3% Cu. The process includes forming a non-densified metal sheet by consolidating a powder having an intermetallic alloy composition such as by roll compaction, tape casting or plasma spraying, forming a cold rolled sheet by cold rolling the non-densified metal sheet so as to increase the density and reduce the thickness thereof and annealing the cold rolled sheet. The powder can be a water, polymer or gas atomized powder which is subjecting to sieving and/or blending with a binder prior to the consolidation step. After the consolidation step, the sheet can be partially sintered. The cold rolling and/or annealing steps can be repeated to achieve the desired sheet thickness and properties. The annealing can be carried out in a vacuum furnace with a vacuum or inert atmosphere. During final annealing, the cold rolled sheet recrystallizes to an average grain size of about 10 to 30 .mu.m. Final stress relief annealing can be carried out in the B2 phase temperature range.

Strength-Ductility Property Maps of Powder Metallurgy (PM) Ti-6Al-4V Alloy: A Critical Review of Processing-Structure-Property Relationships

NASA Astrophysics Data System (ADS)

Kumar, P.; Chandran, K. S. Ravi

2017-05-01

A comprehensive assessment of tensile properties of powder metallurgical (PM) processed Ti-6Al-4V alloy, through the mapping of strength-ductility property domains, is performed in this review. Tensile property data of PM Ti-6Al-4V alloys made from blended element (BE) and pre-alloyed powders including that additive manufactured (AM) from powders, as well as that made using titanium hydride powders, have been mapped in the form of strength-ductility domains. Based on this, porosity and microstructure have been identified as the dominant variables controlling both the strength and the tensile ductility of the final consolidated materials. The major finding is that tensile ductility of the PM titanium is most sensitive to the presence of pores. The significance of extreme-sized pores or defects in inducing large variations in ductility is emphasized. The tensile strength, however, has been found to depend only weakly on the porosity. The effect of microstructure on properties is masked by the variations in porosity and to some extent by the oxygen level. It is shown that any meaningful comparison of the microstructure can only be made under a constant porosity or density level. The beneficial effect of a refined microstructure is also brought out by logically organizing the data in terms of microstructure groups. The advantages of new processes, using titanium hydride powder to produce PM titanium alloys, in simultaneously increasing strength and ductility, are also highlighted. The tensile properties of AM Ti-6Al-4V alloys are also brought to light, in comparison with the other PM and wrought alloys, through the strength-ductility maps.

Simultaneous perception of a spoken and a signed language: The brain basis of ASL-English code-blends

PubMed Central

Weisberg, Jill; McCullough, Stephen; Emmorey, Karen

2018-01-01

Code-blends (simultaneous words and signs) are a unique characteristic of bimodal bilingual communication. Using fMRI, we investigated code-blend comprehension in hearing native ASL-English bilinguals who made a semantic decision (edible?) about signs, audiovisual words, and semantically equivalent code-blends. English and ASL recruited a similar fronto-temporal network with expected modality differences: stronger activation for English in auditory regions of bilateral superior temporal cortex, and stronger activation for ASL in bilateral occipitotemporal visual regions and left parietal cortex. Code-blend comprehension elicited activity in a combination of these regions, and no cognitive control regions were additionally recruited. Furthermore, code-blends elicited reduced activation relative to ASL presented alone in bilateral prefrontal and visual extrastriate cortices, and relative to English alone in auditory association cortex. Consistent with behavioral facilitation observed during semantic decisions, the findings suggest that redundant semantic content induces more efficient neural processing in language and sensory regions during bimodal language integration. PMID:26177161

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

Development of an Inhaled Dry-Powder Formulation of Tobramycin Using PulmoSphere™ Technology

PubMed Central

Weers, Jeffry; Heuerding, Silvia

2011-01-01

Abstract At present, the only approved inhaled antipseudomonal antibiotics for chronic pulmonary infections in patients with cystic fibrosis (CF) are nebulized solutions. However, prolonged administration and cleaning times, high administration frequency, and cumbersome delivery technologies with nebulizers add to the high treatment burden in this patient population. PulmoSphere™ technology is an emulsion-based spray-drying process that enables the production of light porous particle, dry-powder formulations, which exhibit improved flow and dispersion from passive dry powder inhalers. This review explores the fundamental characteristics of PulmoSphere technology, focusing on the development of a dry powder formulation of tobramycin for the treatment of chronic pulmonary Pseudomonas aeruginosa (Pa) infection in CF patients. This dry powder formulation provides substantially improved intrapulmonary deposition efficiency, faster delivery, and more convenient administration over nebulized formulations. The availability of more efficient and convenient treatment options may improve treatment compliance, and thereby therapeutic outcomes in CF. PMID:21395432

An Alkylated Indacenodithieno[3,2-b]thiophene-Based Nonfullerene Acceptor with High Crystallinity Exhibiting Single Junction Solar Cell Efficiencies Greater than 13% with Low Voltage Losses.

PubMed

Fei, Zhuping; Eisner, Flurin D; Jiao, Xuechen; Azzouzi, Mohammed; Röhr, Jason A; Han, Yang; Shahid, Munazza; Chesman, Anthony S R; Easton, Christopher D; McNeill, Christopher R; Anthopoulos, Thomas D; Nelson, Jenny; Heeney, Martin

2018-02-01

A new synthetic route, to prepare an alkylated indacenodithieno[3,2-b]thiophene-based nonfullerene acceptor (C8-ITIC), is reported. Compared to the reported ITIC with phenylalkyl side chains, the new acceptor C8-ITIC exhibits a reduction in the optical band gap, higher absorptivity, and an increased propensity to crystallize. Accordingly, blends with the donor polymer PBDB-T exhibit a power conversion efficiency (PCE) up to 12.4%. Further improvements in efficiency are found upon backbone fluorination of the donor polymer to afford the novel material PFBDB-T. The resulting blend with C8-ITIC shows an impressive PCE up to 13.2% as a result of the higher open-circuit voltage. Electroluminescence studies demonstrate that backbone fluorination reduces the energy loss of the blends, with PFBDB-T/C8-ITIC-based cells exhibiting a small energy loss of 0.6 eV combined with a high J SC of 19.6 mA cm -2 . © 2018 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Systematic Approach to Faculty Development toward Improved Capability in Tertiary Teaching in a Blended Learning Environment

ERIC Educational Resources Information Center

Badawood, Ashraf Mohammad

2011-01-01

The blended learning (BL) approach provides an efficient and effective instructional experience. However, adopting BL poses some challenge to faculty; the most important obstacle found in this research is faculty's lack of knowledge regarding the use of technology in their teaching. This challenge prompted the researcher to identify a solution…

The Influence of the Use of Technology on Student Outcomes in a Blended Learning Context

ERIC Educational Resources Information Center

López-Pérez, María V.; Pérez-López, María C.; Rodríguez-Ariza, Lázaro; Argente-Linares, Eva

2013-01-01

In blended learning, the internet acts as an instrument to complement traditional forms of instruction, in the belief that the incorporation of new information and communication technologies may lead to more efficient and effective education. This paper presents a study carried out in the University of Granada, during the first year of…

Integration of Endnote Online in Information Literacy Instruction Designed for Small and Large Chemistry Courses

ERIC Educational Resources Information Center

Baykoucheva, Svetla; Houck, Joseph D.; White, Natalia

2016-01-01

The blended model for information literacy instruction described in this article introduces students not only to efficient techniques for finding scientific literature and properties of chemical compounds, but also to managing this information with a bibliographic management program (EndNote Online). The model blends face-to-face instruction with…

Challenges of Blended E-Learning Tools in Mathematics: Students' Perspectives University of Uyo

ERIC Educational Resources Information Center

Umoh, Joseph B.; Akpan, Ekemini T.

2014-01-01

An in-depth knowledge of pedagogical approaches can help improve the formulation of effective and efficient pedagogy, tools and technology to support and enhance the teaching and learning of Mathematics in higher institutions. This study investigated students' perceptions of the challenges of blended e-learning tools in the teaching and learning…

Influence of the Formulation Parameters on the Particle Size and Encapsulation Efficiency of Resveratrol in PLA and PLA-PEG Blend Nanoparticles: A Factorial Design.

PubMed

Lindner, Gabriela da Rocha; Dalmolin, Luciana Facco; Khalil, Najeh Maissar; Mainardes, Rubiana Mara

2015-12-01

Polymeric nanoparticles are colloidal systems that promote protection and modification of physicochemical characteristics of a drug and that also ensure controlled and extended drug release. This paper reports a 2(3) factorial design study to optimize poly(lactide) (PLA) and poly(lactide)-polyethylene glycol (PLA-PEG) blend nanoparticles containing resveratrol (RVT) for prolonged release. The independent variables analyzed were solvent composition, surfactant concentration and ratio of aqueous to organic phase (two levels each factor). Mean particle size and RVT encapsulation efficiency were set as the dependent variables. The selected optimized parameters were set as organic phase comprised of a mixture of dichloromethane and ethyl acetate, 1% of surfactant polyvinyl alcohol and a 3:1 ratio of aqueous to organic phase, for both PLA and PLA-PEG blend nanoparticles. This formulation originated nanoparticles with size of 228 ± 10 nm and 185 ± 70 nm and RVT encapsulation efficiency of 82 ± 10% and 76 ± 7% for PLA and PLA-PEG blend nanoparticles, respectively. The in vitro release study showed a biphasic pattern with prolonged RVT release and PEG did not influence the RVT release. The in vitro release data were in favor of Higuchi-diffusion kinetics for both nanoformulations and the Kossmeyer-Peppas coefficient indicated that anomalous transport was the main release mechanism of RVT. PLA and PLA-PEG blend nanoparticles produced with single emulsion-solvent evaporation technology were found to be a promising approach for the incorporation of RVT and promoted its controlled release. The factorial design is a tool of great value in choosing formulations with optimized parameters.

Additive Manufacturing of SiC Based Ceramics and Ceramic Matrix Composites

NASA Technical Reports Server (NTRS)

Halbig, Michael Charles; Singh, Mrityunjay

2015-01-01

Silicon carbide (SiC) ceramics and SiC fiber reinforcedSiC ceramic matrix composites (SiCSiC CMCs) offer high payoff as replacements for metals in turbine engine applications due to their lighter weight, higher temperature capability, and lower cooling requirements. Additive manufacturing approaches can offer game changing technologies for the quick and low cost fabrication of parts with much greater design freedom and geometric complexity. Four approaches for developing these materials are presented. The first two utilize low cost 3D printers. The first uses pre-ceramic pastes developed as feed materials which are converted to SiC after firing. The second uses wood containing filament to print a carbonaceous preform which is infiltrated with a pre-ceramic polymer and converted to SiC. The other two approaches pursue the AM of CMCs. The first is binder jet SiC powder processing in collaboration with rp+m (Rapid Prototyping+Manufacturing). Processing optimization was pursued through SiC powder blending, infiltration with and without SiC nano powder loading, and integration of nanofibers into the powder bed. The second approach was laminated object manufacturing (LOM) in which fiber prepregs and laminates are cut to shape by a laser and stacked to form the desired part. Scanning electron microscopy was conducted on materials from all approaches with select approaches also characterized with XRD, TGA, and bend testing.

Charge transfer complex in diketopyrrolopyrrole polymers and fullerene blends: Implication for organic solar cell efficiency

NASA Astrophysics Data System (ADS)

Moghe, D.; Yu, P.; Kanimozhi, C.; Patil, S.; Guha, S.

2012-02-01

Copolymers based on diketopyrrolopyrrole (DPP) have recently gained potential in organic photovoltaics. When blended with another acceptor such as PCBM, intermolecular charge transfer occurs which may result in the formation of charge transfer (CT) states. We present here the spectral photocurrent characteristics of two donor-acceptor DPP based copolymers, PDPP-BBT and TDPP-BBT, blended with PCBM to identify the CT states. The spectral photocurrent measured using Fourier-transform photocurrent spectroscopy (FTPS) and monochromatic photocurrent (PC) methods are compared with P3HT:PCBM, where the CT state is well known. PDPP-BBT:PCBM shows a stable CT state while TDPP-BBT does not. Our analysis shows that the larger singlet state energy difference between TDPP-BBT and PCBM along with the lower optical gap of TDPP-BBT obliterates the formation of a midgap CT state resulting in an enhanced photovoltaic efficiency over PDPP-BBT:PCBM.

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

Ghosh, B.B.

The object of the study reported in this paper was to investigate the possibility of using the blend of kerosene with petrol in a gasoline engines, without much losses in performance. The authors carried out experiments on a four-stroke cycle Briggs and Stratton S. I. Engine using five blends of kerosene with petrol at a compression ratios 5.3 and 7.47 to 1 with and without surge chambers, at a constant engine speed of 1500 rev/min with the following conclusions: 1. At part-load and the lower compression ratio the brake thermal efficiency is improved with percentage increase of kerosene but atmore » the higher compression ratio it is improved only upto 50% kerosene blend with petrol. 2. The knock-free maximum bhp is reduced with (a) the percentage increase of kerosene, (b) the increase of compression ratio. 3. Use of a surge chamber increase the knock-free maximum bhp, and reduces the brake thermal efficiency.« less

MFPG. The Role of Coatings in the Prevention of Mechanical Failures. Proceedings of the 23rd Meeting of the Mechanical Failures Prevention Group, Held at the National Bureau of Standards, Gaithersburg, Maryland on October 29-31, 1975

DTIC Science & Technology

1976-09-01

testing evaluation and production process development . This coated microspherical fuel particle has been successfully developed over a period of...this reliable concept began with attempts to blend ceramic (oxide or carbide) fuel powders into a graphite matrix in the early concepts of ROVER, HTGR ...lubricants. An ongoing program at the Naval Air Development Center is investigating how some parameters affect corro- sion between solid film

Method for producing chemical energy

DOEpatents

Jorgensen, Betty S.; Danen, Wayne C.

2004-09-21

Fluoroalkylsilane-coated metal particles having a central metal core, a buffer layer surrounding the core, and a fluoroalkylsilane layer attached to the buffer layer are prepared by combining a chemically reactive fluoroalkylsilane compound with an oxide coated metal particle having a hydroxylated surface. The resulting fluoroalkylsilane layer that coats the particles provides them with excellent resistance to aging. The particles can be blended with oxidant particles to form energetic powder that releases chemical energy when the buffer layer is physically disrupted so that the reductant metal core can react with the oxidant.

Specific Heat of Octahydro - 1,3,5,7 - Tetranitro - 1,3,5,7 - Tetrazocine (HMX).

DTIC Science & Technology

1983-01-01

impurities probably consist of molecules of similar atomic weights as those present in the HMX molecule. Usually the major impurity in HMX is RDX (5...crystal and powdered blend HMX . Data beyond the normal transformation temperature (i.e. 0*6 transition ) were obtained from 472 to 486*K. Also, due to the...Cady, H.H.; Smith, L.C., "Studies on the Polymorphs of HMX ," Los Alamos Scientific Laboratory, Los Alamos, N.M., LAMS-2652, May 1962. (6) Brill, T.B

Damage tolerant light absorbing material

DOEpatents

Lauf, Robert J.; Hamby, Jr., Clyde; Akerman, M. Alfred; Seals, Roland D.

1993-01-01

A light absorbing article comprised of a composite of carbon-bonded carbon fibers, prepared by: blending carbon fibers with a carbonizable organic powder to form a mixture; dispersing the mixture into an aqueous slurry; vacuum molding the aqueous slurry to form a green article; drying and curing the green article to form a cured article; and, carbonizing the cured article at a temperature of at least about 1000.degree. C. to form a carbon-bonded carbon fiber light absorbing composite article having a bulk density less than 1 g/cm.sup.3.

Damage tolerant light absorbing material

DOEpatents

Lauf, R.J.; Hamby, C. Jr.; Akerman, M.A.; Seals, R.D.

1993-09-07

A light absorbing article comprised of a composite of carbon-bonded carbon fibers, is prepared by: blending carbon fibers with a carbonizable organic powder to form a mixture; dispersing the mixture into an aqueous slurry; vacuum molding the aqueous slurry to form a green article; drying and curing the green article to form a cured article; and, carbonizing the cured article at a temperature of at least about 1000 C to form a carbon-bonded carbon fiber light absorbing composite article having a bulk density less than 1 g/cm[sup 3]. 9 figures.

Californium--palladium metal neutron source material

DOEpatents

Dahlen, B.L.; Mosly, W.C. Jr.; Smith, P.K.; Albenesius, E.L.

1974-01-22

Californium, as metal or oxide, is uniformly dispersed throughout a noble metal matrix, provided in compact, rod or wire form. A solution of californium values is added to palladium metal powder, dried, blended and pressed into a compact having a uni-form distribution of californium. The californium values are decomposed to californium oxide or metal by heating in an inert or reducing atmosphere. Sintering the compact to a high density closes the matrix around the dispersed californium. The sintered compact is then mechanically shaped into an elongated rod or wire form. (4 claims, no drawings) (Official Gazette)

Additive Manufacturing of Silicon Carbide-Based Ceramic Matrix Composites: Technical Challenges and Opportunities

NASA Technical Reports Server (NTRS)

Singh, Mrityunjay; Halbig, Michael C.; Grady, Joseph E.

2016-01-01

Advanced SiC-based ceramic matrix composites offer significant contributions toward reducing fuel burn and emissions by enabling high overall pressure ratio (OPR) of gas turbine engines and reducing or eliminating cooling air in the hot-section components, such as shrouds, combustor liners, vanes, and blades. Additive manufacturing (AM), which allows high value, custom designed parts layer by layer, has been demonstrated for metals and polymer matrix composites. However, there has been limited activity on additive manufacturing of ceramic matrix composites (CMCs). In this presentation, laminated object manufacturing (LOM), binder jet process, and 3-D printing approaches for developing ceramic composite materials are presented. For the laminated object manufacturing (LOM), fiber prepreg laminates were cut into shape with a laser and stacked to form the desired part followed by high temperature heat treatments. For the binder jet, processing optimization was pursued through silicon carbide powder blending, infiltration with and without SiC nano powder loading, and integration of fibers into the powder bed. Scanning electron microscopy was conducted along with XRD, TGA, and mechanical testing. Various technical challenges and opportunities for additive manufacturing of ceramics and CMCs will be presented.

Structural, morphological and optical properties of ZnSe quantum dot thin films.

PubMed

Zedan, I T; Azab, A A; El-Menyawy, E M

2016-02-05

ZnSe powder was prepared via hydrothermal technique using zinc acetate and sodium selenite as source materials. The prepared ZnSe powder was used for preparing film with different thickness values (95, 135 and 230 nm) via thermal evaporation technique. X-ray diffraction showed that the prepared powder has cubic zinc-blende structure with a space group, F43m. The high resolution transmittance electron microscope results show that the films are composed of spherical-shaped nanoparticles with a diameter in the range of 2-8 nm. The optical properties of ZnSe films with differing thicknesses are investigated by means of spectrophotometric measurements of the photoluminescence, transmittance and reflectance. The absorption coefficient of the films is calculated and the optical band gap is estimated. The refractive index of the films is determined and its normal dispersion behavior is analyzed on the basis of a single oscillator model, in which oscillator energy, dispersion energy and dielectric constant at high frequency are evaluated. Drude model is also applied to determine the lattice dielectric constant and the ratio of the carriers' concentration to their effective mass. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of the variation in the ambient moisture on the compaction behavior of powder undergoing roller-compaction and on the characteristics of tablets produced from the post-milled granules.

PubMed

Gupta, Abhay; Peck, Garnet E; Miller, Ronald W; Morris, Kenneth R

2005-10-01

Effect of variation in the ambient moisture levels on the compaction behavior of a 10% acetaminophen (APAP) powder blend in microcrystalline cellulose (MCC) powder was studied by comparing the physical and mechanical properties of ribbons prepared by roller compaction with those of simulated ribbons, i.e., tablets prepared under uni-axial compression. Relative density, moisture content, tensile strength, and Young's modulus were used as key compact properties for comparison. Moisture was found to facilitate the particle rearrangement of both, the APAP and the MCC particles, as well as the deformation of the MCC particles. The tensile strength of the simulated ribbons also showed an increase with increasing moisture content. An interesting observation was that the tensile strength of the roller compacted samples first increased and then decreased with increasing moisture content. Variation in the ambient moisture during roller compaction was also found to influence the characteristics of tablets produced from the granules obtained post-milling the ribbons. A method to study this influence is also reported. Copyright (c) 2005 Wiley-Liss, Inc. and the American Pharmacists Association

Physical characteristics and magnetic properties of BaFe{sub 12}O{sub 19}/SrTiO{sub 3} based composites derived from mechanical alloying

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

Widodo, Rahmat Doni, E-mail: rahmat-doni@yahoo.com; Manaf, Azwar

2016-04-19

A composite system BaFe{sub 12}O{sub 19}/SrTiO{sub 3} with ferrimagnetic BaFe{sub 12}O{sub 19} phase (BHF) and ferroelectric SrTiO{sub 3} phase (STO) have been prepared by mechanical alloying and subsequent heat treatment. The composite powders were studied by Particle Size Analyze, X-ray diffraction and magnetic measurement. It was found that the particle size of composite powders initially increased due to laminated layers formation of a composite and then decreased to an asymptotic value of ∼8 µm as the milling time extended even to a relatively longer time. However, based on results of line broadening analysis the mean grain size of the particles wasmore » found in the nanometer scale. We thus believed that mechanical blending and milling of mixture components for the composite materials has promoted heterogeneous nucleation and only after successive sintering at 1100°C the milled powder transformed into particles of nanograin. In this report, microstructure as well as magnetic properties for the composite is also briefly discussed.« less

Impact of Electrostatics on Processing and Product Performance of Pharmaceutical Solids.

PubMed

Desai, Parind Mahendrakumar; Tan, Bernice Mei Jin; Liew, Celine Valeria; Chan, Lai Wah; Heng, Paul Wan Sia

2015-01-01

Manufacturing of pharmaceutical solids involves different unit operations and processing steps such as powder blending, fluidization, sieving, powder coating, pneumatic conveying and spray drying. During these operations, particles come in contact with other particles, different metallic, glass or polymer surfaces and can become electrically charged. Electrostatic charging often gives a negative connotation as it creates sticking, jamming, segregation or other issues during tablet manufacturing, capsule filling, film packaging and other pharmaceutical operations. A thorough and fundamental appreciation of the current knowledge of mechanisms and the potential outcomes is essential in order to minimize potential risks resulting from this phenomenon. The intent of this review is to discuss the electrostatic properties of pharmaceutical powders, equipment surfaces and devices affecting pharmaceutical processing and product performance. Furthermore, the underlying mechanisms responsible for the electrostatic charging are described and factors affecting electrostatic charging have been reviewed in detail. Feasibility of different methods used in the laboratory and pharmaceutical industry to measure charge propensity and decay has been summarized. Different computational and experimental methods studied have proven that the particle charging is a very complex phenomenon and control of particle charging is extremely important to achieve reliable manufacturing and reproducible product performance.

Real-time assessment of critical quality attributes of a continuous granulation process.

PubMed

Fonteyne, Margot; Vercruysse, Jurgen; Díaz, Damián Córdoba; Gildemyn, Delphine; Vervaet, Chris; Remon, Jean Paul; De Beer, Thomas

2013-02-01

There exists the intention to shift pharmaceutical manufacturing of solid dosage forms from traditional batch production towards continuous production. The currently applied conventional quality control systems, based on sampling and time-consuming off-line analyses in analytical laboratories, would annul the advantages of continuous processing. It is clear that real-time quality assessment and control is indispensable for continuous production. This manuscript evaluates strengths and weaknesses of several complementary Process Analytical Technology (PAT) tools implemented in a continuous wet granulation process, which is part of a fully continuous from powder-to-tablet production line. The use of Raman and NIR-spectroscopy and a particle size distribution analyzer is evaluated for the real-time monitoring of critical parameters during the continuous wet agglomeration of an anhydrous theophylline- lactose blend. The solid state characteristics and particle size of the granules were analyzed in real-time and the critical process parameters influencing these granule characteristics were identified. The temperature of the granulator barrel, the amount of granulation liquid added and, to a lesser extent, the powder feed rate were the parameters influencing the solid state of the active pharmaceutical ingredient (API). A higher barrel temperature and a higher powder feed rate, resulted in larger granules.

Optimizing the vacuum plasma spray deposition of metal, ceramic, and cermet coatings using designed experiments

NASA Astrophysics Data System (ADS)

Kingswell, R.; Scott, K. T.; Wassell, L. L.

1993-06-01

The vacuum plasma spray (VPS) deposition of metal, ceramic, and cermet coatings has been investigated using designed statistical experiments. Processing conditions that were considered likely to have a significant influence on the melting characteristics of the precursor powders and hence deposition efficiency were incorporated into full and fractional factorial experimental designs. The processing of an alumina powder was very sensitive to variations in the deposition conditions, particularly the injection velocity of the powder into the plasma flame, the plasma gas composition, and the power supplied to the gun. Using a combination of full and fractional factorial experimental designs, it was possible to rapidly identify the important spraying variables and adjust these to produce a deposition efficiency approaching 80 percent. The deposition of a nickel-base alloy metal powder was less sensitive to processing conditions. Generally, however, a high degree of particle melting was achieved for a wide range of spray conditions. Preliminary experiments performed using a tungsten carbide/cobalt cermet powder indicated that spray efficiency was not sensitive to deposition conditions. However, microstructural analysis revealed considerable variations in the degree of tungsten carbide dissolution. The structure and properties of the optimized coatings produced in the factorial experiments are also discussed.

Efficient reductive elimination of bromate in water using zero-valent zinc prepared by acid-washing treatments.

PubMed

Lin, Kun-Yi Andrew; Lin, Chu-Hung; Lin, Jia-Yin

2017-10-15

Although zero valent zinc (ZVZ) is a strong reductant, studies using ZVZ for bromate reduction are rare. In this study, ZVZ is prepared by acid-washing zinc powder with HCl and used to reduce bromate. The effect of acid-washing on the morphology of zinc powder is also examined. Zinc powder inefficiently reduces bromate, but ZVZ obtained by acid-washing zinc powder eliminates bromate and converts it to bromide. A higher dose of ZVZ enhances elimination efficiency perhaps because the formation of a passivation layer of zinc oxide could be scattered on the large surface of ZVZ. Elevated temperature also substantially improves both elimination efficiency and kinetics. The effect of pH is shown to have the most significant impact on the bromate elimination; elimination efficiency and kinetics are tremendously bolstered at pH = 3, whereas the elimination of bromate is completely suppressed under alkaline conditions. ZVZ can reduce bromate to bromide even in the presence of other anions and also be reused multiple times. Thus, ZVZ can be easily prepared and used to efficiently reduce bromate to bromide. The findings presented here are essential to the design and implementation of bromate elimination in water using zero-valent metals. Copyright © 2017 Elsevier Inc. All rights reserved.

A Novel Approach for Dry Powder Coating of Pellets with Ethylcellulose. Part II: Evaluation of Caffeine Release.

PubMed

Albertini, Beatrice; Melegari, Cecilia; Bertoni, Serena; Dolci, Luisa Stella; Passerini, Nadia

2018-04-01

The objective of this study was to assess the efficacy and the capability of a novel ethylcellulose-based dry-coating system to obtain prolonged and stable release profiles of caffeine-loaded pellets. Lauric and oleic acids at a suitable proportion were used to plasticize ethylcellulose. The effect of coating level, percentage of drug loading, inert core particle size, and composition of the coating formulation including the anti-sticking agent on the drug release profile were fully investigated. A coating level of 15% w/w was the maximum layered amount which could modify the drug release. The best controlled drug release was obtained by atomizing talc (2.5% w/w) together with the solid plasticizer during the dry powder-coating process. SEM pictures revealed a substantial drug re-crystallization on the pellet surface, and the release studies evidenced that caffeine diffused through the plasticized polymer acting as pore former. Therefore, the phenomenon of caffeine migration across the coating layer had a strong influence on the permeability of the coating membrane. Comparing dry powder-coated pellets to aqueous film-coated ones, drug migration happened during storage, though more sustained release profiles were obtained. The developed dry powder-coating process enabled the production of stable caffeine sustained release pellets. Surprisingly, the release properties of the dry-coated pellets were mainly influenced by the way of addition of talc into the dry powder-coating blend and by the drug nature and affinity to the coating components. It would be interesting to study the efficacy of novel coating system using a different API.

Understanding the effect of lactose particle size on the properties of DPI formulations using experimental design.

PubMed

Guenette, Estelle; Barrett, Andrew; Kraus, Debbie; Brody, Rachel; Harding, Ljiljana; Magee, Gavin

2009-10-01

Medicines for delivering therapeutic agents to the lung as dry powders primarily consist of a carrier and a micronised active pharmaceutical ingredient (API). The performance of an inhaled formulation will depend on a number of factors amongst which the particle size distribution (PSD) plays a key role. It is suggested that increasing the number of fine particles in the carrier can improve the aerosolisation of the API. In addition the effect of PSD upon a bulk powder is also broadly understood in terms of powder flow. Other aspects of functionality that different size fractions of the carrier affect are not clearly understood; for example, it is not yet clearly known how different size fractions contribute to the different functionalities of the carrier. It is the purpose of this investigation to examine the effects of different lactose size fractions on fine particle dose, formulation stability and the ability to process and fill the material in the preferred device. In order to understand the true impact of the size fractions of lactose on the performance of dry powder inhaled (DPI) products, a statistically designed study has been conducted. The study comprised various DPI blend formulations prepared using lactose monohydrate carrier systems consisting of mixtures of four size fractions. Interactive mixtures were prepared containing 1% (w/w) salbutamol sulphate. The experimental design enabled the evaluation of the effect of lactose size fractions on processing and performance attributes of the formulation. Furthermore, the results of the study demonstrate that an experimental design approach can be used successfully to support dry powder formulation development.

[The study of ultra-fine diamond powder used in magnetic head polishing slurry].

PubMed

Jin, Hong-Yun; Hou, Shu-En; Pan, Yong; Xiao, Hong-Yan

2008-05-01

In the present paper, atomic absorption spectrometry(AAS), inductively-coupled plasma mass spectrometry (ICP-MS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and laser Raman spectroscopy (RM) were employed to study the commercial ultra-fine diamond powders prepared by the static pressure-catalyst method and used in magnetic head polishing slurry. The results of AAS and ICP-MS indicated that there were silicon oxide, Fe, Ni, Al and some other metal elements in the ultra-fine powders. XRD patterns showed the peaks of SiO2 at 2theta = 35.6 degrees, 39.4 degrees and 59.7 degrees and diamond sharp peaks in agreement with the results above. Diamond sharp peaks implied perfect crystal and high-hardness beneficial to high-efficiency in polishing. The broader Raman band of graphite at 1 592 cm(-1) observed by Raman analysis proved graphite existing in the diamond powders. In the TEM images, the size of ultra-fine powders was estimated between 0.1 and 0.5 microm distributed in a wide scope, however, sharp edges of the powder particles was useful to polish. The ultra-fine diamond powders have many advantages, for example, high-hardness, well abrasion performance, high-polishing efficiency and being useful in magnetic head polishing slurry. But, the impurities influence the polishing efficiency, shortening its service life and the wide distribution reduces the polishing precision. Consequently, before use the powders must be purified and classified. The purity demands is 99.9% and trace silicon oxide under 0.01% should be reached. The classification demands that the particle distribution should be in a narrower scope, with the mean size of 100 nm and the percentage of particles lager than 200 nm not over 2%.

Preparation of redispersible liposomal dry powder using an ultrasonic spray freeze-drying technique for transdermal delivery of human epithelial growth factor

PubMed Central

Yin, Fei; Guo, Shiyan; Gan, Yong; Zhang, Xinxin

2014-01-01

In this work, an ultrasonic spray freeze-drying (USFD) technique was used to prepare a stable liposomal dry powder for transdermal delivery of recombinant human epithelial growth factor (rhEGF). Morphology, particle size, entrapment efficiency, in vitro release, and skin permeability were systematically compared between rhEGF liposomal dry powder prepared using USFD and that prepared using a conventional lyophilization process. Porous and spherical particles with high specific area were produced under USFD conditions. USFD effectively avoided formation of ice crystals, disruption of the bilayer structure, and drug leakage during the liposome drying process, and maintained the stability of the rhEGF liposomal formulation during storage. The reconstituted rhEGF liposomes prepared from USFD powder did not show significant changes in morphology, particle size, entrapment efficiency, or in vitro release characteristics compared with those of rhEGF liposomes before drying. Moreover, the rhEGF liposomal powder prepared with USFD exhibited excellent enhanced penetration in ex vivo mouse skin compared with that for powder prepared via conventional lyophilization. The results suggest that ultrasonic USFD is a promising technique for the production of stable protein-loaded liposomal dry powder for application to the skin. PMID:24729702

Preparation of redispersible liposomal dry powder using an ultrasonic spray freeze-drying technique for transdermal delivery of human epithelial growth factor.

PubMed

Yin, Fei; Guo, Shiyan; Gan, Yong; Zhang, Xinxin

2014-01-01

In this work, an ultrasonic spray freeze-drying (USFD) technique was used to prepare a stable liposomal dry powder for transdermal delivery of recombinant human epithelial growth factor (rhEGF). Morphology, particle size, entrapment efficiency, in vitro release, and skin permeability were systematically compared between rhEGF liposomal dry powder prepared using USFD and that prepared using a conventional lyophilization process. Porous and spherical particles with high specific area were produced under USFD conditions. USFD effectively avoided formation of ice crystals, disruption of the bilayer structure, and drug leakage during the liposome drying process, and maintained the stability of the rhEGF liposomal formulation during storage. The reconstituted rhEGF liposomes prepared from USFD powder did not show significant changes in morphology, particle size, entrapment efficiency, or in vitro release characteristics compared with those of rhEGF liposomes before drying. Moreover, the rhEGF liposomal powder prepared with USFD exhibited excellent enhanced penetration in ex vivo mouse skin compared with that for powder prepared via conventional lyophilization. The results suggest that ultrasonic USFD is a promising technique for the production of stable protein-loaded liposomal dry powder for application to the skin.

Estimates of increased black carbon emissions from electrostatic precipitators during powdered activated carbon injection for mercury emissions control.

PubMed

Clack, Herek L

2012-07-03

The behavior of mercury sorbents within electrostatic precipitators (ESPs) is not well-understood, despite a decade or more of full-scale testing. Recent laboratory results suggest that powdered activated carbon exhibits somewhat different collection behavior than fly ash in an ESP and particulate filters located at the outlet of ESPs have shown evidence of powdered activated carbon penetration during full-scale tests of sorbent injection for mercury emissions control. The present analysis considers a range of assumed differential ESP collection efficiencies for powdered activated carbon as compared to fly ash. Estimated emission rates of submicrometer powdered activated carbon are compared to estimated emission rates of particulate carbon on submicrometer fly ash, each corresponding to its respective collection efficiency. To the extent that any emitted powdered activated carbon exhibits size and optical characteristics similar to black carbon, such emissions could effectively constitute an increase in black carbon emissions from coal-based stationary power generation. The results reveal that even for the low injection rates associated with chemically impregnated carbons, submicrometer particulate carbon emissions can easily double if the submicrometer fraction of the native fly ash has a low carbon content. Increasing sorbent injection rates, larger collection efficiency differentials as compared to fly ash, and decreasing sorbent particle size all lead to increases in the estimated submicrometer particulate carbon emissions.

Hole-Transfer Dependence on Blend Morphology and Energy Level Alignment in Polymer: ITIC Photovoltaic Materials.

PubMed

Eastham, Nicholas D; Logsdon, Jenna L; Manley, Eric F; Aldrich, Thomas J; Leonardi, Matthew J; Wang, Gang; Powers-Riggs, Natalia E; Young, Ryan M; Chen, Lin X; Wasielewski, Michael R; Melkonyan, Ferdinand S; Chang, Robert P H; Marks, Tobin J

2018-01-01

Bulk-heterojunction organic photovoltaic materials containing nonfullerene acceptors (NFAs) have seen remarkable advances in the past year, finally surpassing fullerenes in performance. Indeed, acceptors based on indacenodithiophene (IDT) have become synonymous with high power conversion efficiencies (PCEs). Nevertheless, NFAs have yet to achieve fill factors (FFs) comparable to those of the highest-performing fullerene-based materials. To address this seeming anomaly, this study examines a high efficiency IDT-based acceptor, ITIC, paired with three donor polymers known to achieve high FFs with fullerenes, PTPD3T, PBTI3T, and PBTSA3T. Excellent PCEs up to 8.43% are achieved from PTPD3T:ITIC blends, reflecting good charge transport, optimal morphology, and efficient ITIC to PTPD3T hole-transfer, as observed by femtosecond transient absorption spectroscopy. Hole-transfer is observed from ITIC to PBTI3T and PBTSA3T, but less efficiently, reflecting measurably inferior morphology and nonoptimal energy level alignment, resulting in PCEs of 5.34% and 4.65%, respectively. This work demonstrates the importance of proper morphology and kinetics of ITIC → donor polymer hole-transfer in boosting the performance of polymer:ITIC photovoltaic bulk heterojunction blends. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Blended learning in health education: three case studies.

PubMed

de Jong, Nynke; Savin-Baden, Maggi; Cunningham, Anne Marie; Verstegen, Daniëlle M L

2014-09-01

Blended learning in which online education is combined with face-to-face education is especially useful for (future) health care professionals who need to keep up-to-date. Blended learning can make learning more efficient, for instance by removing barriers of time and distance. In the past distance-based learning activities have often been associated with traditional delivery-based methods, individual learning and limited contact. The central question in this paper is: can blended learning be active and collaborative? Three cases of blended, active and collaborative learning are presented. In case 1 a virtual classroom is used to realize online problem-based learning (PBL). In case 2 PBL cases are presented in Second Life, a 3D immersive virtual world. In case 3 discussion forums, blogs and wikis were used. In all cases face-to-face meetings were also organized. Evaluation results of the three cases clearly show that active, collaborative learning at a distance is possible. Blended learning enables the use of novel instructional methods and student-centred education. The three cases employ different educational methods, thus illustrating diverse possibilities and a variety of learning activities in blended learning. Interaction and communication rules, the role of the teacher, careful selection of collaboration tools and technical preparation should be considered when designing and implementing blended learning.

Effect of mineral admixtures on kinetic property and compressive strength of self Compacting Concrete

NASA Astrophysics Data System (ADS)

Jagalur Mahalingasharma, Srishaila; Prakash, Parasivamurthy; Vishwanath, K. N.; Jawali, Veena

2017-06-01

This paper presents experimental investigations made on the influence of chemical, physical, morphological and mineralogical properties of mineral admixtures such as fly ash, ground granulate blast furnace slag, metakaoline and micro silica used as a replacement of cement in self compacting concrete on workability and compressive strength. Nineteen concrete mixes were cast by replacing with cement by fly ash or ground granulated blast furnace slag as binary blend at 30%, 40%, 50% and with addition of micro silica and metakaoline at 10% as a ternary blend with fly ash, ground granulated blast furnace slag and obtained results were compare with control mix. Water powder ratio 0.3 and super plasticizer dosage 1% of cementitious material was kept constant for all the mixes. The self compacting concrete tested for slump flow, V-funnel, L-Box, J-Ring, T50, and compressive strength on concrete cube were determined at age of 3, 7, 28, 56, 90 days.

Chemopreventive and therapeutic activity of dietary blueberry against estrogen-mediated breast cancer.

PubMed

Jeyabalan, Jeyaprakash; Aqil, Farrukh; Munagala, Radha; Annamalai, Lakshmanan; Vadhanam, Manicka V; Gupta, Ramesh C

2014-05-07

Berries are gaining increasing importance lately for their chemopreventive and therapeutic potential against several cancers. In earlier studies, a blueberry-supplemented diet has shown protection against 17β-estradiol (E2)-mediated mammary tumorigenesis. This study tested both preventive and therapeutic activities of diet supplemented with whole blueberry powder (50:50 blend of Tifblue and Rubel). Animals received 5% blueberry diet, either 2 weeks prior to or 12 weeks after E2 treatment in preventive and therapeutic groups, respectively. Both interventions delayed the tumor latency for palpable mammary tumors by 28 and 37 days, respectively. Tumor volume and multiplicity were also reduced significantly in both modes. The effect on mammary tumorigenesis was largely due to down-regulation of CYP 1A1 and ER-α gene expression and also favorable modulation of microRNA (miR-18a and miR-34c) levels. These data suggest that the blueberry blend tested is effective in inhibiting E2-mediated mammary tumorigenesis in both preventive and therapeutic modes.

Navigating E-Learning and Blended Learning for Pre-Service Teachers: Redesigning for Engagement, Access and Efficiency

ERIC Educational Resources Information Center

Chigeza, Philemon; Halbert, Kelsey

2014-01-01

Nebulous combinations of face-to-face and online learning are increasingly common across Australian higher education contexts. This paper reports on part of a redesign project of an undergraduate education subject at a regional university. The aim of the redesign was to enhance e-learning and blended learning environments. An approach that maps…

U.S. Air Force Energy Program

DTIC Science & Technology

2011-05-01

prepared to acquire 50% of domestic aviation fuel requirements via an alternative fuel blend by 2016 Installation Energy  Reduce energy intensity by...FY10  On track to certify fleet on synthetic fuel blend by early 2011 Installation Energy  Reduced installation energy intensity nearly 15% since... Winglets Manufacturing Methods Propulsion Integration Alt Fuels Analysis New Efficient Engines Legacy Aircraft Energy Harvesting Weight-optimized

The Transition to Blended Learning in a School of Nursing at a Developing Country: An Evaluation

ERIC Educational Resources Information Center

Alarbeed, Adham; Al Hakim, Diala

2014-01-01

Within the past two decades, Blended Learning (BL) programs have become very prevalent. The number of offered courses is continually increasing. The factors which support this fact are mostly related to the technological advances that have made the obtainability both efficient and practical. A School of Nursing (SoN) started a Faculty Professional…

"Blending" Docent Learning: Using Google Forms Quizzes to Increase Efficiency in Interpreter Education at Fort Henry

ERIC Educational Resources Information Center

Murphy, Michael P. A.

2018-01-01

The introduction of online elements to museums and cultural sites has opened up new ways for visitors to engage with the past, with nature, with culture, and all other treasures of the museum. However, docent training has lagged behind visitor-facing educational initiatives. By blending online elements into docent education programs, staff…

Preparation and antibacterial activities of chitosan-gallic acid/polyvinyl alcohol blend film by LED-UV irradiation.

PubMed

Yoon, Soon-Do; Kim, Young-Mog; Kim, Boo Il; Je, Jae-Young

2017-11-01

Active blend films from chitosan-gallic acid (CGA) and polyvinyl alcohol (PVA) were prepared via a simple mixing and casting method through the addition of citric acid as a plasticizer. The CGA/PVA blend films were characterized using Fourier transform infrared spectroscopy (FT-IR). The mechanical properties including tensile strength (TS) and elongation at break (%E), degree of solubility (S) and swelling behavior (DS), water vapor adsorption, and antimicrobial activities of the CGA/PVA blend films with and without LED (light emitting diode)-UV irradiation were also investigated. The CGA/PVA blend films exposed to UV irradiation exerted a higher TS (43.5MPa) and lower %E (50.40), S (0.38) and DS (2.73) compared to the CGA/PVA blend films (TS=41.7MPa, %E=55.40, S=0.42, and DS=3.16) not exposed LED-UV irradiation, indicating that the cross-linkage between CGA and PVA had been strengthened by LED-UV irradiation. However, the water vapor adsorption in the CGA/PVA blend films increased due to the changes of surface roughness and pore volume after LED-UV irradiation, and all values increased by increasing the CGA concentrations in the CGA/PVA blend films. The antimicrobial activities of the CGA/PVA blend films showed that the efficient concentration of CGA in the CGA/PVA blend films was over 1.0%. Taken together, the CGA/PVA blend films have potential for use as food packing materials. Copyright © 2017 Elsevier B.V. All rights reserved.

Optimization of matrix solid-phase dispersion for the rapid determination of salicylate and benzophenone-type UV absorbing substances in marketed fish.

PubMed

Tsai, Dung-Ying; Chen, Chien-Liang; Ding, Wang-Hsien

2014-07-01

A simple and effective method for the rapid determination of five salicylate and benzophenone-type UV absorbing substances in marketed fish is described. The method involves the use of matrix solid-phase dispersion (MSPD) prior to their determination by on-line silylation gas chromatography tandem mass spectrometry (GC-MS/MS). The parameters that affect the extraction efficiency were optimized using a Box-Behnken design method. The optimal extraction conditions involved dispersing 0.5g of freeze-dried powdered fish with 1.0g of Florisil using a mortar and pestle. This blend was then transferred to a solid-phase extraction (SPE) cartridge containing 1.0g of octadecyl bonded silica (C18), as the clean-up co-sorbent. The target analytes were then eluted with 7mL of acetonitrile. The extract was derivatized on-line in the GC injection-port by reaction with a trimethylsilylating (TMS) reagent. The TMS-derivatives were then identified and quantitated by GC-MS/MS. The limits of quantitation (LOQs) were less than 0.1ng/g. Copyright © 2014 Elsevier Ltd. All rights reserved.

Continuous melt granulation: Influence of process and formulation parameters upon granule and tablet properties.

PubMed

Monteyne, Tinne; Vancoillie, Jochem; Remon, Jean-Paul; Vervaet, Chris; De Beer, Thomas

2016-10-01

The pharmaceutical industry has a growing interest in alternative manufacturing models allowing automation and continuous production in order to improve process efficiency and reduce costs. Implementing a switch from batch to continuous processing requires fundamental process understanding and the implementation of quality-by-design (QbD) principles. The aim of this study was to examine the relationship between formulation-parameters (type binder, binder concentration, drug-binder miscibility), process-parameters (screw speed, powder feed rate and granulation temperature), granule properties (size, size distribution, shape, friability, true density, flowability) and tablet properties (tensile strength, friability, dissolution rate) of four different drug-binder formulations using Design of experiments (DOE). Two binders (polyethylene glycol (PEG) and Soluplus®) with a different solid state, semi-crystalline vs amorphous respectively, were combined with two model-drugs, metoprolol tartrate (MPT) and caffeine anhydrous (CAF), both having a contrasting miscibility with the binders. This research revealed that the granule properties of miscible drug-binder systems depended on the powder feed rate and barrel filling degree of the granulator whereas the granule properties of immiscible systems were mainly influenced by binder concentration. Using an amorphous binder, the tablet tensile strength depended on the granule size. In contrast, granule friability was more important for tablet quality using a brittle binder. However, this was not the case for caffeine-containing blends, since these phenomena were dominated by the enhanced compression properties of caffeine Form I, which was formed during granulation. Hence, it is important to gain knowledge about formulation behavior during processing since this influences the effect of process parameters onto the granule and tablet properties. Copyright © 2016 Elsevier B.V. All rights reserved.

Performance improvement of gel- and solid-state dye-sensitized solar cells by utilization the blending effect of poly (vinylidene fluoride-co-hexafluropropylene) and poly (acrylonitrile-co-vinyl acetate) co-polymers

NASA Astrophysics Data System (ADS)

Venkatesan, Shanmugam; Obadja, Nesia; Chang, Ting-Wei; Chen, Li-Tung; Lee, Yuh-Lang

2014-12-01

Poly (vinylidene fluoride-co-hexafluropropylene) (PVDF-HFP) and poly (acrylonitrile-co-vinyl acetate) (PAN-VA) are used as gelator to prepare gel- and solid-state polymer electrolytes for dye sensitized solar cells (DSSCs) applications. The electrolytes prepared using PVDF-HFP have higher conductivities than those prepared using PAN-VA. In blended polymers, the conductivities of the electrolytes increase with increasing composition of PVDF-HFP; at 75% PVDF-HFP, conductivity of the blended polymer surpassed that of pure polymers. It is also found that the viscosity of the electrolyte prepared by PAN-VA (1.2 kPaS) is much lower than that by PVDF-HFP (11 kPaS). Therefore, increasing PAN-VA composition can decrease the viscosity of the electrolyte, improving the penetration of electrolytes in the TiO2 matrix. By controlling the ratio of PVDF-HFP/PAN-VA, the conductivity and viscosity of the electrolyte can be regulated and an optimal ratio based on the conversion efficiency of the gel- and solid state DSSCs is obtained at the ratio of 3/1. The highest efficiency achieved by the gel- and solid-state cells using the blending polymers are 6.3% and 4.88%, respectively, which are higher than those prepared using pure polymers (5.53% and 4.56%, respectively). The introduction of TiO2 fillers to the solid electrolyte can further increase the cell efficiency to 5.34%.

Highly Efficient Ternary-Blend Polymer Solar Cells Enabled by a Nonfullerene Acceptor and Two Polymer Donors with a Broad Composition Tolerance.

PubMed

Xu, Xiaopeng; Bi, Zhaozhao; Ma, Wei; Wang, Zishuai; Choy, Wallace C H; Wu, Wenlin; Zhang, Guangjun; Li, Ying; Peng, Qiang

2017-12-01

In this work, highly efficient ternary-blend organic solar cells (TB-OSCs) are reported based on a low-bandgap copolymer of PTB7-Th, a medium-bandgap copolymer of PBDB-T, and a wide-bandgap small molecule of SFBRCN. The ternary-blend layer exhibits a good complementary absorption in the range of 300-800 nm, in which PTB7-Th and PBDB-T have excellent miscibility with each other and a desirable phase separation with SFBRCN. In such devices, there exist multiple energy transfer pathways from PBDB-T to PTB7-Th, and from SFBRCN to the above two polymer donors. The hole-back transfer from PTB7-Th to PBDB-T and multiple electron transfers between the acceptor and the donor materials are also observed for elevating the whole device performance. After systematically optimizing the weight ratio of PBDB-T:PTB7-Th:SFBRCN, a champion power conversion efficiency (PCE) of 12.27% is finally achieved with an open-circuit voltage (V oc ) of 0.93 V, a short-circuit current density (J sc ) of 17.86 mA cm -2 , and a fill factor of 73.9%, which is the highest value for the ternary OSCs reported so far. Importantly, the TB-OSCs exhibit a broad composition tolerance with a high PCE over 10% throughout the whole blend ratios. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dried plum products as a substitute for phosphate in chicken marinade.

PubMed

Jarvis, Nathan; Clement, Ashley R; O'Bryan, Corliss A; Babu, Dinesh; Crandall, Philip G; Owens, Casey M; Meullenet, Jean-Francois; Ricke, Steven C

2012-06-01

In order to address the growing demand for more natural poultry products, alkaline phosphates commonly used in chicken breast meat marinades were replaced with plum ingredients and evaluated. For initial sensory evaluation, 200 consumers of chicken were served a small portion of the chicken breast on a plate and were asked to evaluate the product for overall impression, flavor, and texture on a 9-point hedonic scale with 1 = "dislike extremely" and 9 = "like extremely." Also, a 5-point just-about-right (JAR) scale was used on questions about tenderness, juiciness, overall flavor, and saltiness. Both hedonic and JAR demonstrated that the marinades of plum concentrate and the blend of plum fiber and powder were not distinguishable from the control (P > 0.05). Using two different percentages of fiber/powder blend, two different percentages of concentrate, sodium tripolyphosphate (STPP), and no marinade, measurements were made for marinade per cent pickup, thaw loss, and cook loss. Plum concentrate at 1.1% was most similar to STPP in marinade per cent pickup, thaw loss, drip loss, and cook loss. These results show that plum ingredients can potentially be used as a substitute in standard phosphate marinades. Consumers are increasingly demanding more natural foods with less artificial additives. This research presents the results of experiments using dried plum ingredients as a substitute for phosphates commonly used in marinades for chicken. Results indicate that dried plum ingredients may be a suitable substitute for phosphates in marinades. Journal of Food Science © 2012 Institute of Food Technologists® No claim to original US government works.

Mixing Study in a Multi-dimensional Motion Mixer

NASA Astrophysics Data System (ADS)

Shah, R.; Manickam, S. S.; Tomei, J.; Bergman, T. L.; Chaudhuri, B.

2009-06-01

Mixing is an important but poorly understood aspect in petrochemical, food, ceramics, fertilizer and pharmaceutical processing and manufacturing. Deliberate mixing of granular solids is an essential operation in the production of industrial powder products usually constituted from different ingredients. The knowledge of particle flow and mixing in a blender is critical to optimize the design and operation. Since performance of the product depends on blend homogeneity, the consequence of variability can be detrimental. A common approach to powder mixing is to use a tumbling blender, which is essentially a hollow vessel horizontally attached to a rotating shaft. This single axis rotary blender is one of the most common batch mixers among in industry, and also finds use in myriad of application as dryers, kilns, coaters, mills and granulators. In most of the rotary mixers the radial convection is faster than axial dispersion transport. This slow dispersive process hinders mixing performance in many blending, drying and coating applications. A double cone mixer is designed and fabricated which rotates around two axes, causing axial mixing competitive to its radial counterpart. Discrete Element Method (DEM) based numerical model is developed to simulate the granular flow within the mixer. Digitally recorded mixing states from experiments are used to fine tune the numerical model. Discrete pocket samplers are also used in the experiments to quantify the characteristics of mixing. A parametric study of the effect of vessel speeds, relative rotational speed (between two axes of rotation), on the granular mixing is investigated by experiments and numerical simulation. Incorporation of dual axis rotation enhances axial mixing by 60 to 85% in comparison to single axis rotation.

Optimization of Rice bran biodiesel blends on CI engine and investigating its effects

NASA Astrophysics Data System (ADS)

Jayaprabakar, J.; Dey, Biraj; Dey, Krishanu; Hareesh, Batchu; Anish, M.

2017-05-01

Bio-diesel can be produced from various plant oils like soybean, sunflower or rice bran. Here the focus is on converting the rice bran oil into bio-diesel which is produced by transesterifying the rice bran oil with a low molecular weight alcohol (methanol) and a non-conventional catalyst (lipase). Using a lipase based catalyst brings down the cost of bio diesel production significantly by reducing the number of washing cycles and its ability to be reused further. Four different blends of B10, B20, B30, B40 and straight diesel are tested in a single cylinder, fourstroke, vertical air cooled Kirloskar Diesel Engine having ignition timing of 23° before Top Dead Centre (TDC). As compared to straight diesel the Brake Thermal Efficiency (BTE) value for all the blends are higher. The Specific Fuel Consumption (BSFC) values for most of the blends are less as compared to diesel. Emissions of CO, CO2 and HC for all the blends decreased quite significantly. As a summary, the blend B20 records better performance as well as emission characteristics as compared to diesel.

Experimental investigation on performance and exhaust emissions of castor oil biodiesel from a diesel engine.

PubMed

Shojaeefard, M H; Etgahni, M M; Meisami, F; Barari, A

2013-01-01

Biodiesel, produced from plant and animal oils, is an important alternative to fossil fuels because, apart from dwindling supply, the latter are a major source of air pollution. In this investigation, effects of castor oil biodiesel blends have been examined on diesel engine performance and emissions. After producing castor methyl ester by the transesterification method and measuring its characteristics, the experiments were performed on a four cylinder, turbocharged, direct injection, diesel engine. Engine performance (power, torque, brake specific fuel consumption and thermal efficiency) and exhaust emissions were analysed at various engine speeds. All the tests were done under 75% full load. Furthermore, the volumetric blending ratios of biodiesel with conventional diesel fuel were set at 5, 10, 15, 20 and 30%. The results indicate that lower blends of biodiesel provide acceptable engine performance and even improve it. Meanwhile, exhaust emissions are much decreased. Finally, a 15% blend of castor oil-biodiesel was picked as the optimized blend of biodiesel-diesel. It was found that lower blends of castor biodiesel are an acceptable fuel alternative for the engine.

A comparative study of almond biodiesel-diesel blends for diesel engine in terms of performance and emissions.

PubMed

Abu-Hamdeh, Nidal H; Alnefaie, Khaled A

2015-01-01

This paper investigates the opportunity of using almond oil as a renewable and alternative fuel source. Different fuel blends containing 10, 30, and 50% almond biodiesel (B10, B30, and B50) with diesel fuel (B0) were prepared and the influence of these blends on emissions and some performance parameters under various load conditions were inspected using a diesel engine. Measured engine performance parameters have generally shown a slight increase in exhaust gas temperature and in brake specific fuel consumption and a slight decrease in brake thermal efficiency. Gases investigated were carbon monoxide (CO) and oxides of nitrogen (NOx). Furthermore, the concentration of the total particulate and the unburned fuel emissions in the exhaust gas were tested. A blend of almond biodiesel with diesel fuel gradually reduced the engine CO and total particulate emissions compared to diesel fuel alone. This reduction increased with more almond biodiesel blended into the fuel. Finally, a slight increase in engine NO x using blends of almond biodiesel was measured.

Regulated and unregulated emissions from a diesel engine fueled with biodiesel and biodiesel blended with methanol

NASA Astrophysics Data System (ADS)

Cheung, C. S.; Zhu, Lei; Huang, Zhen

Experiments were carried out on a diesel engine operating on Euro V diesel fuel, pure biodiesel and biodiesel blended with methanol. The blended fuels contain 5%, 10% and 15% by volume of methanol. Experiments were conducted under five engine loads at a steady speed of 1800 rev min -1 to assess the performance and the emissions of the engine associated with the application of the different fuels. The results indicate an increase of brake specific fuel consumption and brake thermal efficiency when the diesel engine was operated with biodiesel and the blended fuels, compared with the diesel fuel. The blended fuels could lead to higher CO and HC emissions than biodiesel, higher CO emission but lower HC emission than the diesel fuel. There are simultaneous reductions of NO x and PM to a level below those of the diesel fuel. Regarding the unregulated emissions, compared with the diesel fuel, the blended fuels generate higher formaldehyde, acetaldehyde and unburned methanol emissions, lower 1,3-butadiene and benzene emissions, while the toluene and xylene emissions not significantly different.

A Comparative Study of Almond Biodiesel-Diesel Blends for Diesel Engine in Terms of Performance and Emissions

PubMed Central

Alnefaie, Khaled A.

2015-01-01

This paper investigates the opportunity of using almond oil as a renewable and alternative fuel source. Different fuel blends containing 10, 30, and 50% almond biodiesel (B10, B30, and B50) with diesel fuel (B0) were prepared and the influence of these blends on emissions and some performance parameters under various load conditions were inspected using a diesel engine. Measured engine performance parameters have generally shown a slight increase in exhaust gas temperature and in brake specific fuel consumption and a slight decrease in brake thermal efficiency. Gases investigated were carbon monoxide (CO) and oxides of nitrogen (NOx). Furthermore, the concentration of the total particulate and the unburned fuel emissions in the exhaust gas were tested. A blend of almond biodiesel with diesel fuel gradually reduced the engine CO and total particulate emissions compared to diesel fuel alone. This reduction increased with more almond biodiesel blended into the fuel. Finally, a slight increase in engine NOx using blends of almond biodiesel was measured. PMID:25874218

A Polymer Electrolyte for Dye-Sensitized Solar Cells Based on a Poly(Polyvinylidenefluoride-Co-Hexafluoropropylene)/Hydroxypropyl Methyl Cellulose Blend

NASA Astrophysics Data System (ADS)

Won, Lee Ji; Kim, Jae Hong; Thogiti, Suresh

2018-05-01

A novel polymer blend electrolyte for dye-sensitized solar cells (DSSCs) was synthesized by quasi-solidifying a liquid-based electrolyte containing an iodide/triiodide redox couple and supporting salts with a mixture of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and indigenous hydroxypropyl methyl cellulose (HPMC). A high ionic conductivity of 8.8 × 10-4 S cm-1 was achieved after introducing 5 wt% of HPMC with respect to the weight of PVDH-HFP. DSSCs were fabricated using gel polymer blend electrolytes, and the J-V characteristics of the fabricated devices were analyzed. Under optimal conditions, the photovoltaic conversion efficiency of cells with the novel HPMC-blended gel electrolyte (5.34%) was significantly greater than that of cells without HPMC (3.97%).

Vacuum Powder Injector

NASA Technical Reports Server (NTRS)

Working, Dennis C.

1991-01-01

Method developed to provide uniform impregnation of bundles of carbon-fiber tow with low-solubility, high-melt-flow polymer powder materials to produce composite prepregs. Vacuum powder injector expands bundle of fiber tow, applies polymer to it, then compresses bundle to hold powder. System provides for control of amount of polymer on bundle. Crystallinity of polymer maintained by controlled melt on takeup system. All powder entrapped, and most collected for reuse. Process provides inexpensive and efficient method for making composite materials. Allows for coating of any bundle of fine fibers with powders. Shows high potential for making prepregs of improved materials and for preparation of high-temperature, high-modulus, reinforced thermoplastics.

Hot-melt extrusion microencapsulation of quercetin for taste-masking.

PubMed

Khor, Chia Miang; Ng, Wai Kiong; Kanaujia, Parijat; Chan, Kok Ping; Dong, Yuancai

2017-02-01

Besides its poor dissolution rate, the bitterness of quercetin also poses a challenge for further development. Using carnauba wax, shellac or zein as the shell-forming excipient, this work aimed to microencapsulate quercetin by hot-melt extrusion for taste-masking. In comparison with non-encapsulated quercetin, the microencapsulated powders exhibited significantly reduced dissolution in the simulated salivary pH 6.8 medium indicative of their potentially good taste-masking efficiency in the order of zein > carnauba wax > shellac. In vitro bitterness analysis by electronic tongue confirmed the good taste-masking efficiency of the microencapsulated powders. In vitro digestion results showed that carnauba wax and shellac-microencapsulated powders presented comparable dissolution rate with the pure quercetin in pH 1.0 (gastric) and 6.8 (intestine) medium; while zein-microencapsulated powders exhibited a remarkably slower dissolution rate. Crystallinity of quercetin was slightly reduced after microencapsulation while its chemical structure remained unchanged. Hot-melt extrusion microencapsulation could thus be an attractive technique to produce taste-masked bioactive powders.

Evaluation of biochar powder on oxygen supply efficiency and global warming potential during mainstream large-scale aerobic composting.

PubMed

He, Xueqin; Chen, Longjian; Han, Lujia; Liu, Ning; Cui, Ruxiu; Yin, Hongjie; Huang, Guangqun

2017-12-01

This study investigated the effects of biochar powder on oxygen supply efficiency and global warming potential (GWP) in the large-scale aerobic composting pattern which includes cyclical forced-turning with aeration at the bottom of composting tanks in China. A 55-day large-scale aerobic composting experiment was conducted in two different groups without and with 10% biochar powder addition (by weight). The results show that biochar powder improves the holding ability of oxygen, and the duration time (O 2 >5%) is around 80%. The composting process with above pattern significantly reduce CH 4 and N 2 O emissions compared to the static or turning-only styles. Considering the average GWP of the BC group was 19.82% lower than that of the CK group, it suggests that rational addition of biochar powder has the potential to reduce the energy consumption of turning, improve effectiveness of the oxygen supply, and reduce comprehensive greenhouse effects. Copyright © 2017. Published by Elsevier Ltd.

Influence of Ceramic Powder Size on Process of Cermet Coating Formation by Cold Spray

NASA Astrophysics Data System (ADS)

Sova, A.; Papyrin, A.; Smurov, I.

2009-12-01

Influence of the ceramic particle size on the process of formation of cermet coatings by cold spray is experimentally studied. A specially developed nozzle with separate injection of ceramic and metal powders into the gas stream is used in the experiments. The results obtained demonstrate that fine ceramic powders (Al2O3, SiC) produce a strong activation effect on the process of spraying soft metal (Al, Cu) and increase deposition efficiency of the metal component of the mixture compared to the pure metal spraying. At the same time, coarse ceramic powder produces a strong erosion effect that considerably reduces coating mass growth and deposition efficiency of the metal component. It is experimentally shown that the addition of fine hard powder to soft metals as Al and Cu allows to significantly reduce the “critical” temperature (the minimum gas stagnation temperature at which a nonzero particle deposition is observed) for spraying these metals.

Influence of Different Supplements on the Commercial Cultivation of Milky White Mushroom

PubMed Central

Alam, Nuhu; Amin, Ruhul; Khair, Abul

2010-01-01

Calocybe indica, known as milky white mushroom, grows and cultivated in the sub-tropical and temperate zones of South Asia. We investigated the most suitable supplements and their levels for the commercial cultivation of milky white mushroom. Rice bran, maize powder, and wheat bran with their different levels (10, 20, 30, 40, and 50%) were used as supplements to evaluate the yield and yield contributing characteristics of C. indica. Primordia initiation was observed between 13.5 and 19.3 days. The results indicated that the 30% maize powder supplement was effective for producing viable fruiting bodies. The maximum diameters of the pileus and stalk were observed with 30% maize powder. The highest biological and economic yield and biological efficiency were also obtained with 30% maize powder as a supplement. The results indicate that increasing the supplement level resulted in less biological efficiency, and that 30% maize powder was the best supplement level for rice straw substrate to cultivate milky white mushrooms. PMID:23956652

Formulation of a novel fixed dose combination of salmeterol xinafoate and mometasone furoate for inhaled drug delivery.

PubMed

Liu, Sha; Watts, Alan B; Du, Ju; Bui, Amanda; Hengsawas, Soraya; Peters, Jay I; Williams, Robert O

2015-10-01

Co-administration of an inhaled corticosteroid and long acting beta agonist for chronic obstructive pulmonary disease has reduced mortality compared to either drug alone. This combination reduces exacerbations, hospitalization, emergency department visits and health care costs. A novel fixed-dose combination of the long acting beta-2 agonist salmeterol xinafoate (SX) and the corticosteroid mometasone furoate (MF) were prepared in a composite particle formulation as brittle matrix powder (BMP) and investigated for suitability as an inhaled combination product. In this study, BMP fixed dose combinations of SX and MF with or without stabilizing excipients (lactose, mannitol, glycine and trehalose) were prepared and characterized with respect to their thermal properties, morphology, aerodynamic performance and physical stability. BMP combination formulations of SX and MF exhibited improved aerodynamic properties when delivered by dry powder inhalation as compared to the micronized blends of the same substances. Aerodynamic evaluation was carried out by next generation pharmaceutical impactor (NGI) with a marketed DPI device. Results demonstrated that co-deposition occurred when SX and MF were formulated together as composite particles in a BMP, while physical blends resulted in inconsistent deposition and dose uniformity. As a result of the bottom-up particle engineering approach, combination BMP formulations allow for dual API composite formulations to be dispersed as aerosolized particles. Aerosolized BMP combination formulations resulted in delivered dose uniformity and co-deposition of each API. Further, an excipient-free formulation, BMP SXMF, delivered approximately 50% of the loaded dose in the respirable range and demonstrated stability at ambient conditions for 6months. Single dose 24-h pharmacokinetic studies in rats demonstrated that lung tissue deposition and blood circulation (AUC0-24h) of two APIs were higher for the BMP combination group exhibiting a significantly higher lung concentration of drugs than for the crystalline physical blend. While high system drug levels are generally undesirable in lung targeted therapies, high blood levels in this rodent study could be indicative of increased pulmonary tissue exposure using BMP formulations. Copyright © 2015 Elsevier B.V. All rights reserved.

Air powder abrasive treatment as an implant surface cleaning method: a literature review.

PubMed

Tastepe, Ceylin S; van Waas, Rien; Liu, Yuelian; Wismeijer, Daniel

2012-01-01

To evaluate the air powder abrasive treatment as an implant surface cleaning method for peri-implantitis based on the existing literature. A PubMed search was conducted to find articles that reported on air powder abrasive treatment as an implant surface cleaning method for peri-implantitis. The studies evaluated cleaning efficiency and surface change as a result of the method. Furthermore, cell response toward the air powder abrasive-treated discs, reosseointegration, and clinical outcome after treatment is also reported. The PubMed search resulted in 27 articles meeting the inclusion criteria. In vitro cleaning efficiency of the method is reported to be high. The method resulted in minor surface changes on titanium specimens. Although the air powder abrasive-treated specimens showed sufficient levels of cell attachment and cell viability, the cell response decreased compared with sterile discs. Considerable reosseointegration between 39% and 46% and improved clinical parameters were reported after treatment when applied in combination with surgical treatment. The results of the treatment are influenced by the powder type used, the application time, and whether powder was applied surgically or nonsurgically. The in vivo data on air powder abrasive treatment as an implant surface cleaning method is not sufficient to draw definitive conclusions. However, in vitro results allow the clinician to consider the method as a promising option for implant surface cleaning in peri-implantitis treatment.

Enhancement of Poly(orthoester) Microspheres for DNA Vaccine Delivery by Blending with Poly(ethylenimine)

PubMed Central

Nguyen, David N.; Raghavan, Shyam S.; Tashima, Lauren M.; Lin, Elizabeth C.; Fredette, Stephen J.; Langer, Robert S.; Wang, Chun

2008-01-01

Poly(ortho ester) (POE) microspheres have been previously shown to possess certain advantages for the in vivo delivery of DNA vaccines. In particular, timing of DNA release from POE microspheres in response to acidic phagosomal pH was shown to be an important factor in determining immunogenicity, which was hypothesized to be linked to the natural progression of antigen presenting cell uptake, transfection, maturation, and antigen presentation. Here we report in vitro characterization of the enhanced the efficacy of POE microspheres by blending poly(ethylenimine) (PEI), a well-characterized cationic transfection agent, into the POE matrix. Blending of a tiny amount of PEI (approximately 0.04 wt%) with POE caused large alterations in POE microsphere properties. PEI provided greater control over the rate of pH-triggered DNA release by doubling the total release time of plasmid DNA and enhanced gene transfection efficiency of the microspheres up to 50-fold without any significant cytotoxicity. Confocal microscopy with labeled PEI and DNA plasmids revealed that PEI caused a surface-localizing distribution of DNA and PEI within the POE microsphere as well as focal co-localization of PEI with DNA. We provide evidence that upon degradation, the microspheres of POE-PEI blends released electrostatic complexes of DNA and PEI, which are responsible for the enhanced gene transfection. Furthermore, blending PEI into the POE microsphere induced 50% to 60% greater phenotypic maturation and activation of bone marrow-derived dendritic cells in vitro, judged by up-regulation of co-stimulatory markers on the cell surface. Physically blending PEI with POE is a simple approach for modulating the properties of biodegradable microspheres in terms of gene transfection efficiency and DNA release kinetics. Combined with the ability to induce maturation of antigen-presenting cells, POE-PEI blended microspheres may be excellent carriers for DNA vaccines. PMID:18400294

Photoluminescence and cathodoluminescence properties of green emitting SrGa2{S}4 : Eu2+ thin film

NASA Astrophysics Data System (ADS)

Chartier, Céline; Benalloul, Paul; Barthou, Charles; Frigerio, Jean-Marc; Mueller, Gerd O.; Mueller-Mach, Regina; Trottier, Troy

2002-02-01

Photoluminescence and cathodoluminescence properties of SrGa2S4 : Eu2+ thin films prepared by reactive RF magnetron sputtering are investigated. Luminescence performances of the phosphor in the thin film form are compared to those of powder samples: the brightness efficiency of thin films is found to be about 30% of the efficiency of powder at low current density. A ratio higher than 40% is expected at higher current density. Thin film screens for FEDs will become a positive alternative to powder screens provided that film quality and light extraction could be improved by optimization of thickness and deposition parameters.

Particle Engineering Via Mechanical Dry Coating in the Design of Pharmaceutical Solid Dosage Forms.

PubMed

Qu, Li; Morton, David A V; Zhou, Qi Tony

2015-01-01

Cohesive powders are problematic in the manufacturing of pharmaceutical solid dosage forms because they exhibit poor flowability, fluidization and aerosolization. These undesirable bulk properties of cohesive powders represent a fundamental challenge in the design of efficient pharmaceutical manufacturing processes. Recently, mechanical dry coating has attracted increasing attention as it can improve the bulk properties of cohesive powders in a cheaper, simpler, safer and more environment-friendly way than the existing solvent-based counterparts. In this review, mechanical dry coating techniques are outlined and their potential applications in formulation and manufacturing of pharmaceutical solid dosage forms are discussed. Reported data from the literature have shown that mechanical dry coating holds promise for the design of superior pharmaceutical solid formulations or manufacturing processes by engineering the interfaces of cohesive powders in an efficient and economical way.

Low cost synthesis of TiO2-C nanocomposite powder for high efficiency visible light photocatalysis

NASA Astrophysics Data System (ADS)

Mohapatra, A. K.; Nayak, J.

2018-04-01

Titanium dioxide-carbon nanocomposite powder was synthesized via a low cost chemical route using oleic acid and titanium tetra-isopropoxide. Since the carbon remained mainly on the surface of the TiO2 nanoparticles, the powder had black color. The composition of the powder was analyzed by X-ray photoelectron spectroscopy and the structure was studied with X-ray diffraction and transmission electron microscopy. The visible photocatalytic activity of the black TiO2 powder was investigated by studying the photo-bleaching of methylene blue under visible light. Our experimental observation showed that the black-TiO2 powder had a higher visible photocatalytic activity compared to the commercial TiO2 powder (P25 Degussa).

The influence of material type and composition of TiO2- ZnO on manufacturing of paste for the application of DSSC

NASA Astrophysics Data System (ADS)

Retnaningsih, L.; Muliani, L.; Aggraini, P. N.; Hidayat, J.

2016-11-01

Research, fabrication and material selection for the application of Dye- sensitized solar cell (DSSC) has been performed on glass FTO (Flour Tin Oxide). The material is used in the form of TiO2 paste, TiO2 powder and ZnO powder. Dye-sensitized solar cell (DSSC), is a fotoelektrokimia-based solar cells where the absorption process light done by the dye molecules and the process of separation of inorganic semiconductor materials by charge of Titanium dioxide (TiO2) and Zinc oxide (ZnO). The purpose of this research is to know the exact composition of TiO2 and ZnO materials in order to produce the best efficiency with DSSC. On this research was done making prototype dye-sensitized solar cell using dye Z 907, and semiconductor nanoparticles TiO2 and ZnO powder that is made into a paste by mixing different composition in two variations of samples: A = ZnO (powder) + 40% TiO2 (powder) and B = 60% TiO2 (powder) (40%) + TiO2 (pasta) 60%. The second variation of this high efficiency is value at sample B i.e. TiO2 (powder) + 40% TiO2 (paste) of 60%.

Influence of charge carrier mobility and morphology on solar cell parameters in devices of mono- and bis-fullerene adducts.

PubMed

Muth, Mathis-Andreas; Mitchell, William; Tierney, Steven; Lada, Thomas A; Xue, Xiang; Richter, Henning; Carrasco-Orozco, Miguel; Thelakkat, Mukundan

2013-12-06

Herein, we analyze charge carrier mobility and morphology of the active blend layer in thin film organic solar cells and correlate them with device parameters. A low band gap donor-acceptor copolymer in combination with phenyl-C61-butyric acid methyl ester (PCBM) or two bis-adduct fullerenes, bis-PCBM and bis-o-quino-dimethane C60 (bis-oQDMC), is investigated. We study the charge transport of polymer:fullerene blends in hole- and electron-only devices using the space-charge limited current method. Lower electron mobilities are observed in both bis-adduct fullerene blends. Hole mobility, however, is decreased only in the blend containing bis-oQDMC. Both bis-adduct fullerene blends show very high open circuit voltage in solar cell devices, but poor photocurrent compared to the standard PCBM blend for an active layer thickness of 200 nm. Therefore, a higher short circuit current is feasible for the polymer:bis-PCBM blend by reducing the active layer thickness in order to compensate for the low electron mobility, which results in a PCE of 4.3%. For the polymer:bis-oQDMC blend, no such improvement is achieved due to an unfavorable morphology in this particular blend system. The results are supported by external quantum efficiency measurements, atomic force microscopy, transmission electron microscopy and UV/vis spectroscopy. Based on these results, the investigations presented herein give a more scientific basis for the optimization of solar cells.

Manufacturing techniques for titanium aluminide based alloys and metal matrix composites

NASA Astrophysics Data System (ADS)

Kothari, Kunal B.

Dual phase titanium aluminides composed vastly of gamma phase (TiAl) with moderate amount of alpha2 phase (Ti3Al) have been considered for several high temperature aerospace and automobile applications. High specific strength coupled with good high temperature performance in the areas of creep and oxidation resistance makes titanium aluminides "materials of choice" for next generation propulsion systems. Titanium alumnides are primarily being considered as potential replacements for Ni-based superalloys in gas turbine engine components with aim of developing more efficient and leaner engines exhibiting high thrust-to-weight ratio. Thermo-mechanical treatments have shown to enhance the mechanical performance of titanium aluminides. Additionally, small additions of interstitial elements have shown further and significant improvement in the mechanical performance of titanium alumnide alloys. However, titanium aluminides lack considerably in room temperature ductility and as a result manufacturing processes of these aluminides have greatly suffered. Traditional ingot metallurgy and investment casting based methods to produce titanium aluminide parts in addition to being expensive, have also been unsuccessful in producing titanium aluminides with the desired mechanical properties. Hence, the manufacturing costs associated with these methods have completely outweighed the benefits offered by titanium aluminides. Over the last two decades, several powder metallurgy based manufacturing techniques have been studied to produce titanium aluminide parts. These techniques have been successful in producing titanium aluminide parts with a homogeneous and refined microstructure. These powder metallurgy techniques also hold the potential of significant cost reduction depending on the wide market acceptance of titanium aluminides. In the present study, a powder metallurgy based rapid consolidation technique has been used to produce near-net shape parts of titanium aluminides. Micron-sized titanium aluminide powders were rapidly consolidated to form near-net shape titanium aluminide parts in form of small discs and tiles. The rapidly consolidated titanium aluminide parts were found to be fully dense. The microstructure morphology was found to vary with consolidation conditions. The mechanical properties were found to be significantly dependent on microstructure morphology and grain size. Due to rapid consolidation, grain growth during consolidation was limited, which in turn led to enhanced mechanical properties. The high temperature mechanical properties for the consolidated titanium aluminide samples were characterized and were found to retain good mechanical performance up to 700°C. Micron-sized titanium aluminide powders with slightly less Aluminum and small Nb, and Cr additions were rapidly consolidated into near-net shape parts. The consolidated parts were found to exhibit enhanced mechanical performance in terms of ductility and yield strength. The negative effect of Oxygen on the flexural strength at high temperatures was found to be reduced with the addition of Nb. In an effort to further reduce the grain size of the consolidated titanium aluminide samples, the as-received titanium aluminide powders were milled in an attrition mill. The average powder particle size of the powders was reduced by 60% after milling. The milled powders were then rapidly consolidated. The grain size of the consolidated parts was found to be in the sub-micrometer range. The mechanical properties were found to be significantly enhanced due to reduction of grain size in the sub-micrometer range. In order to develop a metal matrix composite based on titanium aluminide matrix reinforced with titanium boride, an experiment to study the effect of rapid consolidation on titanium diboride powders was conducted. Micron-sized titanium diboride powders were consolidated and were found to be 93% dense and exhibited minimal grain growth. The low density of the consolidated part was attributed to low consolidation temperature. Titanium aluminide and titanium diboride powders were blended together in an attrition mill and rapidly consolidated. A metal matrix composite with titanium aluminide matrix reinforced with titanium monoboride plates was formed. The titanium diboride in the powder form was found to be transformed to titanium monoboroide plates during consolidation due to the thermodynamic equilibrium between titanium and titanium monoboride. The metal matrix composite was found to be 90% dense. The low density was due to particle size mismatch between the matrix and reinforcement powders and low consolidation temperature. An increase in the volume of titanium monoboride plates in the metal matrix composite was accompanied by an increase in the elastic modulus of the metal matrix composite.

Improved Mo-Re VPS Alloys for High-Temperature Uses

NASA Technical Reports Server (NTRS)

Hickman, Robert; Martin, James; McKechnie, Timothy; O'Dell, John Scott

2011-01-01

Dispersion-strengthened molybdenum- rhenium alloys for vacuum plasma spraying (VPS) fabrication of high-temperature-resistant components are undergoing development. In comparison with otherwise equivalent non-dispersion-strengthened Mo-Re alloys, these alloys have improved high-temperature properties. Examples of VPS-fabricated high-temperature-resistant components for which these alloys are expected to be suitable include parts of aircraft and spacecraft engines, furnaces, and nuclear power plants; wear coatings; sputtering targets; x-ray targets; heat pipes in which liquid metals are used as working fluids; and heat exchangers in general. These alloys could also be useful as coating materials in some biomedical applications. The alloys consist of 60 weight percent Mo with 40 weight percent Re made from (1) blends of elemental Mo and Re powders or (2) Re-coated Mo particles that have been subjected to a proprietary powder-alloying-and-spheroidization process. For most of the dispersion- strengthening experiments performed thus far in this development effort, 0.4 volume percent of transition-metal ceramic dispersoids were mixed into the feedstock powders. For one experiment, the proportion of dispersoid was 1 volume percent. In each case, the dispersoid consisted of either ZrN particles having sizes <45 m, ZrO2 particles having sizes of about 1 m, HfO2 particles having sizes <45 m, or HfN particles having sizes <1 m. These materials were chosen for evaluation on the basis of previously published thermodynamic stability data. For comparison, Mo-Re feedstock powders without dispersoids were also prepared.

A charge carrier transport model for donor-acceptor blend layers

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

Fischer, Janine, E-mail: janine.fischer@iapp.de; Widmer, Johannes; Koerner, Christian

2015-01-28

Highly efficient organic solar cells typically comprise donor-acceptor blend layers facilitating effective splitting of excitons. However, the charge carrier mobility in the blends can be substantially smaller than in neat materials, hampering the device performance. Currently, available mobility models do not describe the transport in blend layers entirely. Here, we investigate hole transport in a model blend system consisting of the small molecule donor zinc phthalocyanine (ZnPc) and the acceptor fullerene C{sub 60} in different mixing ratios. The blend layer is sandwiched between p-doped organic injection layers, which prevent minority charge carrier injection and enable exploiting diffusion currents for themore » characterization of exponential tail states from a thickness variation of the blend layer using numerical drift-diffusion simulations. Trap-assisted recombination must be considered to correctly model the conductivity behavior of the devices, which are influenced by local electron currents in the active layer, even though the active layer is sandwiched in between p-doped contacts. We find that the density of deep tail states is largest in the devices with 1:1 mixing ratio (E{sub t} = 0.14 eV, N{sub t} = 1.2 × 10{sup 18 }cm{sup −3}) directing towards lattice disorder as the transport limiting process. A combined field and charge carrier density dependent mobility model are developed for this blend layer.« less

[An exploratory study of 'blended' cognitive behavioural therapy (CBT) for patients with a panic disorder: results and patients' experiences].

PubMed

Bruinsma, A; Kampman, M; Exterkate, C C; Hendriks, G J

2016-01-01

Digital technology (e-health or 'blended' care), combined with evidence-based face-to-face CBT, is becoming increasingly implemented into mental health care and is expected to result in improved effectiveness and efficiency. To explore the feasibility of blended CBT for patients with a panic disorder. Nine face-to-face sessions of blended CBT (n = 18), supplemented with the digital support of a tabletcomputer and three e-mail contacts, were compared with 12 weekly sessions of regular CBT (n = 18). Primary outcomes were panic frequency and avoidance behaviour; the secondary outcome was general functioning. Patients' experiences of the treatment were collected in the form of a structured interview. The effect sizes found in both the regular and the blended CBT were medium to high (Cohen's d 0.42-1.60). In both types of treatment there was a significant reduction in patients' symptoms. There were no big differences in patient satisfaction regarding the treatment received. The therapists registered 39 face-to-face minutes in the blended treatment but they registered in total 41 fewer face-to-face minutes; this represented a time reduction of 4%. Blended CBT with help of a tablet computer seems to be a suitable method for treating panic disorder psychologically, although the time saved is only moderate. Much more research is needed to ascertain the feasibility and the cost effectiveness of blended CBT.

Strategies for cell manipulation and skeletal tissue engineering using high-throughput polymer blend formulation and microarray techniques.

PubMed

Khan, Ferdous; Tare, Rahul S; Kanczler, Janos M; Oreffo, Richard O C; Bradley, Mark

2010-03-01

A combination of high-throughput material formulation and microarray techniques were synergistically applied for the efficient analysis of the biological functionality of 135 binary polymer blends. This allowed the identification of cell-compatible biopolymers permissive for human skeletal stem cell growth in both in vitro and in vivo applications. The blended polymeric materials were developed from commercially available, inexpensive and well characterised biodegradable polymers, which on their own lacked both the structural requirements of a scaffold material and, critically, the ability to facilitate cell growth. Blends identified here proved excellent templates for cell attachment, and in addition, a number of blends displayed remarkable bone-like architecture and facilitated bone regeneration by providing 3D biomimetic scaffolds for skeletal cell growth and osteogenic differentiation. This study demonstrates a unique strategy to generate and identify innovative materials with widespread application in cell biology as well as offering a new reparative platform strategy applicable to skeletal tissues. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Autonomous healing materials based on epoxidized natural rubber and ethylene methacrylic acid ionomers

NASA Astrophysics Data System (ADS)

Arifur Rahman, Md; Penco, Maurizio; Peroni, Isabella; Ramorino, Giorgio; Janszen, Gerardus; Di Landro, Luca

2012-03-01

The development of autonomous healing material has an enormous scientific and technological interest. In this context, this research work deals with the investigation of autonomous healing behavior of epoxidized natural rubber (ENR) and its blends with ethylene methacrylic acid ionomers. The autonomous healing behavior of ENR and its blends containing two different ionomers [poly(ethylene-co-methacrylic acid sodium salt) (EMNa) and poly(ethylene-co-methacrylic acid zinc salt) (EMZn)] has been studied by ballistic puncture tests. Interestingly, EMNa/ENR blends exhibit complete healing just after the ballistic test but EMZn/ENR blends do not show full self-repairing. The healing efficiency has been evaluated by optical microscopy and a depressurized air-flow test. The healing mechanism has been investigated by characterizing thermal and mechanical properties of the blends. The chemical structure studied by FTIR and thermal analysis show that the ion content of ionomers and functionality of ENR has a significant influence on the self-healing behavior.

Extended-Kalman-filter-based regenerative and friction blended braking control for electric vehicle equipped with axle motor considering damping and elastic properties of electric powertrain

NASA Astrophysics Data System (ADS)

Lv, Chen; Zhang, Junzhi; Li, Yutong

2014-11-01

Because of the damping and elastic properties of an electrified powertrain, the regenerative brake of an electric vehicle (EV) is very different from a conventional friction brake with respect to the system dynamics. The flexibility of an electric drivetrain would have a negative effect on the blended brake control performance. In this study, models of the powertrain system of an electric car equipped with an axle motor are developed. Based on these models, the transfer characteristics of the motor torque in the driveline and its effect on blended braking control performance are analysed. To further enhance a vehicle's brake performance and energy efficiency, blended braking control algorithms with compensation for the powertrain flexibility are proposed using an extended Kalman filter. These algorithms are simulated under normal deceleration braking. The results show that the brake performance and blended braking control accuracy of the vehicle are significantly enhanced by the newly proposed algorithms.

An Efficient, "Burn in" Free Organic Solar Cell Employing a Nonfullerene Electron Acceptor.

PubMed

Cha, Hyojung; Wu, Jiaying; Wadsworth, Andrew; Nagitta, Jade; Limbu, Saurav; Pont, Sebastian; Li, Zhe; Searle, Justin; Wyatt, Mark F; Baran, Derya; Kim, Ji-Seon; McCulloch, Iain; Durrant, James R

2017-09-01

A comparison of the efficiency, stability, and photophysics of organic solar cells employing poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3'″-di(2-octyldodecyl)-2,2';5',2″;5″,2'″-quaterthiophen-5,5'″-diyl)] (PffBT4T-2OD) as a donor polymer blended with either the nonfullerene acceptor EH-IDTBR or the fullerene derivative, [6,6]-phenyl C 71 butyric acid methyl ester (PC 71 BM) as electron acceptors is reported. Inverted PffBT4T-2OD:EH-IDTBR blend solar cell fabricated without any processing additive achieves power conversion efficiencies (PCEs) of 9.5 ± 0.2%. The devices exhibit a high open circuit voltage of 1.08 ± 0.01 V, attributed to the high lowest unoccupied molecular orbital (LUMO) level of EH-IDTBR. Photoluminescence quenching and transient absorption data are employed to elucidate the ultrafast kinetics and efficiencies of charge separation in both blends, with PffBT4T-2OD exciton diffusion kinetics within polymer domains, and geminate recombination losses following exciton separation being identified as key factors determining the efficiency of photocurrent generation. Remarkably, while encapsulated PffBT4T-2OD:PC 71 BM solar cells show significant efficiency loss under simulated solar irradiation ("burn in" degradation) due to the trap-assisted recombination through increased photoinduced trap states, PffBT4T-2OD:EH-IDTBR solar cell shows negligible burn in efficiency loss. Furthermore, PffBT4T-2OD:EH-IDTBR solar cells are found to be substantially more stable under 85 °C thermal stress than PffBT4T-2OD:PC 71 BM devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Efficient process for previous metal recovery from cell membrane electrode assemblies

DOEpatents

Shore, Lawrence; Matlin, Ramail; Heinz, Robert

2010-05-04

A method is provided for recovering a catalytic element from a fuel cell membrane electrode assembly. The method includes grinding the membrane electrode assembly into a powder, extracting the catalytic element by forming a slurry comprising the powder and an acid leachate adapted to dissolve the catalytic element into a soluble salt, and separating the slurry into a depleted powder and a supernatant containing the catalytic element salt. The depleted powder is washed to remove any catalytic element salt retained within pores in the depleted powder and the catalytic element is purified from the salt.

CH3 NH3 PbI3 and HC(NH2 )2 PbI3 Powders Synthesized from Low-Grade PbI2 : Single Precursor for High-Efficiency Perovskite Solar Cells.

PubMed

Zhang, Yong; Kim, Seul-Gi; Lee, Do-Kyoung; Park, Nam-Gyu

2018-05-09

High-efficiency perovskite solar cells are generally fabricated by using highly pure (>99.99 %) PbI 2 mixed with an organic iodide in polar aprotic solvents. However, the use of such an expensive chemical may impede progress toward large-scale industrial applications. Here, we report on the synthesis of perovskite powders by using inexpensive low-grade (99 %) PbI 2 and on the photovoltaic performance of perovskite solar cells prepared from a powder-based single precursor. Pure APbI 3 [A=methylammonium (MA) or formamidinium (FA)] perovskite powders were synthesized by treating low-grade PbI 2 with MAI or FAI in acetonitrile at ambient temperature. The structural phase purity was confirmed by X-ray diffraction. The solar cell with a MAPbI 3 film prepared from the synthesized perovskite powder demonstrated a power conversion efficiency (PCE) of 17.14 %, which is higher than the PCE of MAPbI 3 films prepared by using both MAI and PbI 2 as precursors (PCE=13.09 % for 99 % pure PbI 2 and PCE=16.39 % for 99.9985 % pure PbI 2 ). The synthesized powder showed better absorption and photoluminescence, which were responsible for the better photovoltaic performance. For the FAPbI 3 powder, a solution with a yellow non-perovskite δ-FAPbI 3 powder synthesized at room temperature was found to lead to a black perovskite film, whereas a solution with the black perovskite α-FAPbI 3 powder synthesized at 150 °C was not transformed into a black perovskite film. The α↔δ transition between the powder and film was assumed to correlate with the difference in the iodoplumbates in the powder-dissolved solution. An average PCE of 17.21 % along with a smaller hysteresis [ΔPCE=PCE reverse -PCE forward )=1.53 %] was demonstrated from the perovskite solar cell prepared by using δ-FAPbI 3 powder; this PCE is higher than the average PCE of 17.05 % with a larger hysteresis (ΔPCE=2.71 %) for a device based on a conventional precursor solution dissolving MAI with high-purity PbI 2 . The smaller hysteresis was indicative of fewer defects in the resulting FAPbI 3 film prepared by using the δ-FAPbI 3 powder. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thermomechanical processing of plasma sprayed intermetallic sheets

DOEpatents

Hajaligol, Mohammad R.; Scorey, Clive; Sikka, Vinod K.; Deevi, Seetharama C.; Fleischhauer, Grier; Lilly, Jr., A. Clifton; German, Randall M.

2001-01-01

A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3% Cu. The process includes forming a non-densified metal sheet by consolidating a powder having an intermetallic alloy composition such as by roll compaction, tape casting or plasma spraying, forming a cold rolled sheet by cold rolling the non-densified metal sheet so as to increase the density and reduce the thickness thereof and annealing the cold rolled sheet. The powder can be a water, polymer or gas atomized powder which is subjecting to sieving and/or blending with a binder prior to the consolidation step. After the consolidation step, the sheet can be partially sintered. The cold rolling and/or annealing steps can be repeated to achieve the desired sheet thickness and properties. The annealing can be carried out in a vacuum furnace with a vacuum or inert atmosphere. During final annealing, the cold rolled sheet recrystallizes to an average grain size of about 10 to 30 .mu.m. Final stress relief annealing can be carried out in the B2 phase temperature range.

A photochemical kinetic model for solid dosage forms.

PubMed

Carvalho, Thiago C; La Cruz, Thomas E; Tábora, Jose E

2017-11-01

Photochemical kinetic models to describe the solution phase degradation of pharmaceutical compounds have been extensively reported, but formalisms applicable to the solid phase under polychromatic light have not received as much attention. The objective of this study was to develop a mathematical model to describe the solid state photodegradation of pharmaceutical powder materials under different area/volumetric scales and light exposure conditions. The model considered the previous formalism presented for photodegradation kinetics in solution phase with important elements applied to static powder material being irradiated with a polychromatic light source. The model also included the influence of optical phenomena (i.e. reflectance, scattering factors, etc.) by applying Beer-Lambert law to light attenuation, including effects of powder density. Drug substance and drug product intermediates (blends and tablet cores) were exposed to different light sources and intensities. The model reasonably predicted the photodegradation levels of powder beds of drug substance and drug product intermediates under white and yellow lights with intensities around 5-11kLux. Importantly, the model estimates demonstrated that the reciprocity law for photoreactions was held. Further model evaluation showed that, due to light attenuation, the powder bed is in virtual darkness at cake depths greater than 500μm. At 100μm, the photodegradation of the investigated compound is expected to be close to 100% in 10days under white fluorescent halophosphate light at 9.5kLux. For tablets, defining the volume over exposed surface area ratio is more challenging. Nevertheless, the model can consider a bracket between worst and best cases to provide a reasonable photodegradation estimate. This tool can be significantly leveraged to simulate different light exposure scenarios while assessing photostability risk in order to define appropriate control strategy in manufacturing. Copyright © 2017 Elsevier B.V. All rights reserved.

Mechanisms of Morphology Development and Control in Polymer- Polymer Blends

NASA Astrophysics Data System (ADS)

Macosko, Christopher W.

1998-03-01

Polymer-polymer blends continue to be the most important method for achieving optimization of properties in plastics products. Over 30 percent of all plastics are blends. While miscible blends generally give average properties between the components, immiscible blends offer synergistic possibilities such as high modulus with high toughness; high flow with high impact strength or diffusion barriers with good mechanical properties and low cost. The key to performance of these immiscible blends is their morphology. There are several important types of morphology which can lead to valuable property improvement: emulsion - small polymer spheres well dispersed in a polymer matrix. double emulsion - spheres inside spheres which are dispersed in another matrix. microlayer - thin, parallel layers of one polymer in a matrix. cocontinuous - two (or more) continuous, interpenetrating polymer phases. To be economical it is desirable to create these morphologies via melt mixing of powder or pellets in conventional compounding equipment. The melting stage during compounding is very important for morphology development. This presentation will demonstrate the role of melting or softening of each phase as well as their viscosity, elasticity and interfacial tension in morphology development. Interfacial modification with premade block copolymers or reactively formed copolymers can greatly alter morphology formation and stability. Experimental results will be presented which quantify the role of these additives. References to recent work in this area by our group are listed below: DeBrule, M. B., L. Levitt and C.W. Macosko, "The Rheology and Morphology of Layered Polymer Melts in Shear," Soc. Plastics Eng. Tech Papers (ANTEC), 84-89 (1996). Guegan, P., C. W. Macosko, T. Ishizone, A. Hirao and S. Nakahama, "Kinetics of Chain Coupling at Melt Interfaces, Macromol. 27, 4993-4997 (1994). Lee, M. S., T.P. Lodge, and C. W. Macosko, "Can Random Copolymers Serve as Effective Polymeric Compatibilizers?" accepted for publication by Journal of Polymer Science, Polymer Physics Edition, 1997. Levitt, L. and C. W. Macosko, "Extensional Rheometry of Polymer Multilayers: A Sensitive Probe of Interfaces," J. Rheol, 41, 3, 671-685, (1997). Levitt, L., C.W. Macosko and S.D. Pearson, "Influence of Normal Stress Difference on Polymer Drop Deformation," Polym. Eng. Sci., 36, Part 12, 1647-1655 (1996). Nakayama, A., T. Inoue, A. Hirao, P. Guegan, A. Khandpur, and C. W. Macosko, "Compatibilization of Blends: Effect of Reaction Rate," PPS Proceedings, Sorrento, May 1996. Levitt, L., "Microlayer Morphology Via Polymer Melt Processing, Ph.D. Thesis, Department of Chemical Engineering & Materials Science, University of Minnesota, 1997. Orr, C. A., A. Adedeji, A. Hirao, F. S. Bates, and C. W. Macosko, "Flow-Induced Reactive Self-Assembly", Macromolecules, 30, 4, 1243-1246, (1997). Orr, C. A., "Reactive Compatibilization of Polymer Blends," Ph.D. Thesis, Department of Chemical Engineering & Materials Science, University of Minnesota, 1997. Scott, C. E., and C. W. Macosko, "Morphology Development During the Initial Stages of Polymer-Polymer Blending," Polymer, 36, 461-470 (1995). Scott, C. E. and C. W. Macosko, "Model Experiments Concerning Morphology Development During the Initial Stages of Polymer Blending," Polymer Bulletin 26, 341- 348 (1991). Sundararaj, U., C. K. Shih, and C. W. Macosko, "Evidence For Inversion of Phase Continuity During Morphology Development in Polymer Blending," Polymer Eng. and Sci., 36, 1769-1781 (1996). Sundararaj, U., and C. W. Macosko, "Drop Breakup and Coalescence in Polymer Blends: The Effects of Concentration and Compatibilization, Macromolecules, 28, 2647-2657 (1995). Sundararaj, U., Y. Dori and C. W. Macosko, "Sheet Formation in Immiscible Polymer Blends: Model Experiments on Initial Blend Morphology," Polymer, 36, 1957-1968 (1995). Sundararaj, U., C. W. Macosko, A. Nakayama, and T. Inoue, "Milligrams to Kilograms: An Evaluation of Mixers for Reactive Polymer Blending," Polym. Eng. Sci. 35, 100-114 (1995). Sundararaj, U, R. J. Rolando, H. T. Chan and C. W. Macosko, "Morphology Development in Polymer Blends," Polymer Eng. Sci. 32, 1814-1823 (1992). Utracki, L., Polymer Alloys and Blends; Hanser: New York, 1989.

Highly regioselective terminal alkynes hydroformylation and Pauson-Khand reaction catalysed by mesoporous organised zirconium oxide based powders.

PubMed

Goettmann, Frédéric; Le Floch, Pascal; Sanchez, Clément

2006-01-14

Zirconia-silica mesoporous powders act as very efficient heterogeneous catalysts for both alkyne hydroformylation and Pauson-Khand reaction and yield regioselectivities opposite to those usually observed.

Ultra high purity, dimensionally stable INVAR 36

NASA Technical Reports Server (NTRS)

Sokolowski, Witold M. (Inventor); Lane, Marc S. (Inventor); Odonnell, Timothy P. (Inventor); Hsieh, Cheng H. (Inventor)

1994-01-01

An INVAR 36 material having long-term dimensional stability is produced by sintering a blend of powders of nickel and iron under pressure in an inert atmosphere to form an alloy containing less than 0.01 parts of carbon and less than 0.1 part aggregate and preferably 0.01 part individually of Mn, Si, P, S and Al impurities. The sintered alloy is heat treated and slowly and uniformly cooled to form a material having a coefficient of thermal expansion of less than 1 ppm/C and a temporal stability of less than 1 ppm/year.

Ultra high purity, dimensionally stable INVAR 36

NASA Technical Reports Server (NTRS)

Sokolowski, Witold M. (Inventor); Lane, Marc S. (Inventor); Hsieh, Cheng H. (Inventor); Odonnell, Timothy P. (Inventor)

1995-01-01

An INVAR 36 material having long-term dimensional stability is produced by sintering a blend of powders of nickel and iron under pressure in an inert atmosphere to form an alloy containing less than 0.01 parts of carbon and less than 0.1 part aggregate and preferably 0.01 part individually of Mn, Si, P, S and Al impurities. The sintered alloy is heat treated and slowly and uniformly cooled to form a material having a coefficient of thermal expansion of less than 1 ppm/C and a temporal stability of less than 1 ppm/year.

Functional Biomaterials: Solution Electrospinning and Gelation of Whey Protein and Pullulan

NASA Astrophysics Data System (ADS)

Sullivan, Stephanie Tolstedt

Utilizing biomaterials that are biodegradable, biocompatible and edible serve well for food products as well as biomedical applications. Biomaterials whey protein and pullulan both have these characteristics. Whey proteins (WP) have been used in food products for many years and more recently in pharmaceutical products. They have the ability to form both gels and stable foams. Pullulan (PULL) has also been used in both food and pharmaceutical products, and is a highly water soluble, non-gelling polysaccharide and has been used primarily as a film former. Herein, we investigate the ability of whey protein and pullulan to form nanofibers and gels. Combining their distinct properties allows the ability to uniquely manipulate nanofiber and gel characteristics and behavior for a variety of applications, from food to even tissue scaffolding. First, we determined the electrospinnability of aqueous whey protein solutions. Both whey protein isolate (WPI) and one of its major components beta--lactoglobulin (BLG), either in native or denatured form, yielded interesting micro and nanostructures when electrosprayed; while nanofiber production required blending with a spinnable polymer, poly(ethylene oxide) (PEO). WP:PEO solutions were also successfully electrospun at acidic pH (2≤pH≤3), which could improve shelf life. Fourier Transform Infrared Reflectance (FTIR) analysis of WP:PEO fiber mat indicated some variation in WP secondary structure with varying WPI concentration (as WPI increased, % alpha-helix increased and beta-turn decreased) and pH (as pH decreased from neutral (7.5) to acidic (2), % beta-sheet decreased and alpha-helix increased). X-ray Photoelectron Spectroscopy (XPS) also confirmed the presence of WP on the surface of the blend fibers, augmenting the FTIR analysis. Interestingly, WP:PEO composite nanofibers maintained its fibrous morphology at temperatures as high as 100 °C, above the 60 °C PEO melting point. Further, we show that the blend mats retained a fibrous structure after the heat treatment. Our second goal was to evaluate the ability of aqueous blends of whey protein and pullulan to form gels. We first looked at WP-PULL blend solutions at room temperature, finding an increasing linear trend in low shear viscosity as the relative concentration of pullulan increased. Blend solution samples were then heated to determine the ability of the blend solutions to form a gelled network. Starting with a homogeneous WP gel, adding PULL, at native mix or alkaline pH, maintained a transparent homogeneous microstructure, but resulted in weaker gels based on its response to stress. At WP isoelectric point (IEP) pH, both protein and blend gels became opaque due to protein aggregation, forming a particulate gel. All gels at the IEP were weaker, yielding at much lower stress and corresponding strain, due to the protein aggregation. The addition of transglutaminase enzyme yielded a stronger network than the native samples, while the addition of sodium trimetaphosphate salt yielded weaker gels and also induced relevant particle and/or course stranded microstructure in both pH 8 and IEP cases. The third part of this study demonstrated the ability of pullulan to form nanofibers in the solution electrospinning process. Aqueous pullulan solutions were able to form defect-free nanofibers with a minimum concentration of 15 w/w%. Pullulan and PULL:hydroxypropyl-beta- cyclodextrin (HPBCD) blend fibers were chemically crosslinked to form insoluble fibers using ethylene glycol diglycidyl ether (EGDGE), a chemical used in food contact coating applications. Next, solution blends of pullulan with whey protein were prepared and also electrospun at varying pH and relative biomaterial concentrations at 17 total w/w%. PULL-WP blend nanofiber mats were crosslinked via heat treatment and found to be both swellable and insoluble. When dried, the mats did not return to their original fiber state and instead appear to be gelatinous fibers in nature after soaking, and thereby making them potentially useful for tissue scaffolding applications. A fourth accomplishment was to utilize Near Infrared Reflectance (NIR) Spectroscopy and Chemometrics techniques to analyze commercial whey protein powder characteristics such as protein, fat and moisture content as well as pH. NIR has been utilized in the food and pharmaceutical industries for quality control as a valuable compliment to or replacement for more expensive testing such as High Performance Liquid Chromatography. Analysis resulted in the development of quantitative, linear regression models to correlate whey protein powder characteristics to NIR data. Whey protein's ability to form gels and pullulan's electrospinnability to form nanofibers is combined herein to form blends of both that can be changed with varying concentration, pH, temperature and supplementation with food-safe additives. The study correlates mechanical properties and microstructure of blend gels and nanofibers and provides a foundation for further study of swellable network for tissue application specifically in the use of pullulan-whey protein heat treated nanofiber mats.

An efficient and cost-effective method for preparing transmission electron microscopy samples from powders

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

Wen, Haiming; Lin, Yaojun; Seidman, David N.

The preparation of transmission electron microcopy (TEM) samples from powders with particle sizes larger than ~100 nm poses a challenge. The existing methods are complicated and expensive, or have a low probability of success. Herein, we report a modified methodology for preparation of TEM samples from powders, which is efficient, cost-effective, and easy to perform. This method involves mixing powders with an epoxy on a piece of weighing paper, curing the powder–epoxy mixture to form a bulk material, grinding the bulk to obtain a thin foil, punching TEM discs from the foil, dimpling the discs, and ion milling the dimpledmore » discs to electron transparency. Compared with the well established and robust grinding–dimpling–ion-milling method for TEM sample preparation for bulk materials, our modified approach for preparing TEM samples from powders only requires two additional simple steps. In this article, step-by-step procedures for our methodology are described in detail, and important strategies to ensure success are elucidated. Furthermore, our methodology has been applied successfully for preparing TEM samples with large thin areas and high quality for many different mechanically milled metallic powders.« less

An efficient and cost-effective method for preparing transmission electron microscopy samples from powders

DOE PAGES

Wen, Haiming; Lin, Yaojun; Seidman, David N.; ...

2015-09-09

The preparation of transmission electron microcopy (TEM) samples from powders with particle sizes larger than ~100 nm poses a challenge. The existing methods are complicated and expensive, or have a low probability of success. Herein, we report a modified methodology for preparation of TEM samples from powders, which is efficient, cost-effective, and easy to perform. This method involves mixing powders with an epoxy on a piece of weighing paper, curing the powder–epoxy mixture to form a bulk material, grinding the bulk to obtain a thin foil, punching TEM discs from the foil, dimpling the discs, and ion milling the dimpledmore » discs to electron transparency. Compared with the well established and robust grinding–dimpling–ion-milling method for TEM sample preparation for bulk materials, our modified approach for preparing TEM samples from powders only requires two additional simple steps. In this article, step-by-step procedures for our methodology are described in detail, and important strategies to ensure success are elucidated. Furthermore, our methodology has been applied successfully for preparing TEM samples with large thin areas and high quality for many different mechanically milled metallic powders.« less

Processing of sintered alpha SiC

NASA Technical Reports Server (NTRS)

Storm, R. S.

1984-01-01

Processing methods of sintered alpha SiC for engine applications are developed in a cost effective manner, using a submicron sized powder blended with sintering aids (boron and carbon). The processes for forming a green powder compact, such as dry pressing, cold isostatic pressing and green machining, slip casting, aqueous extrusion, plastic extrusion, and injection molding, are described. Dry pressing is the simplest route to component fabrication, and is carried out at approximately 10,000 psi pressure, while in the cold isostatic method the pressure could go as high as 20,000 psi. Surfactants are added to control settling rates and casting characteristics in the slip casting. The aqueous extrusion process is accomplished by a hydraulic ram forcing the aqueous mixture through a die. The plastic forming processes of extrusion and injection molding offer the potential of greater diversity in shape capacity. The physical properties of sintered alpha SiC (hardness, Young's modulus, shear modulus, and thermal diffusivity) are extensively tested. Corrosion resistance test results of silicon carbide are included.

Kinetics of moisture-induced hydrolysis in powder blends stored at and below the deliquescence relative humidity: investigation of sucrose-citric acid mixtures.

PubMed

Kwok, Kaho; Mauer, Lisa J; Taylor, Lynne S

2010-11-24

Previous studies have shown that deliquescent organic compounds frequently exhibit chemical instability when stored in environmental conditions above their deliquescence relative humidity (RH). The goal of the current study was to investigate the effect of atmospheric moisture on the long-term chemical stability of crystalline sucrose-citric acid mixtures following storage at RHs at and below the mutual deliquescence relative humidity (MDRH). Interestingly, it was found that sucrose hydrolysis can occur below the MDRH of 64% and was observed for samples stored at 54% RH. However, hydrolysis was not seen for samples stored at 33 or 43% RH. The rate of sucrose hydrolysis could be modeled by taking into account the rate and extent of moisture uptake, which in turn was dependent on the composition of the powder and the storage RH. A reaction mechanism initiated by capillary condensation and involving additional deliquescence lowering by the degradation products formed as a result of sucrose hydrolysis (glucose and fructose) was proposed.

High-performance biodegradable polylactide composites fabricated using a novel plasticizer and functionalized eggshell powder.

PubMed

Kong, Junjun; Li, Yi; Bai, Yungang; Li, Zonglin; Cao, Zengwen; Yu, Yancun; Han, Changyu; Dong, Lisong

2018-06-01

A novel polyester poly(diethylene glycol succinate) (PDEGS) was synthesized and evaluated as a plasticizer for polylactide (PLA) in this study. Meanwhile, an effective sustainable filler, functionalized eggshell powder (FES) with a surface layer of calcium phenyphosphonate was also prepared. Then, PLA biocomposites were prepared from FES and PDEGS using a facile melt blending process. The addition of 15 wt% PDEGS as plasticizer showed good miscibility with PLA macromolecules and increased the chain mobility of PLA. The crystallization kinetics of PLA composites revealed that the highly effective nucleating FES significantly improved the crystallization ability of PLA at both of non-isothermal and isothermal conditions. In addition, the effective plasticizer and well-dispersed FES increased the elongation at break from 6% of pure PLA to over 200% for all of the plasticized PLA composites. These biodegradable PLA biocomposites, coupled with excellent crystallization ability and tunable mechanical properties, demonstrate their potential as alternatives to traditional commodity plastics. Copyright © 2018 Elsevier B.V. All rights reserved.

Fly ash reinforced thermoplastic vulcanizates obtained from waste tire powder.

PubMed

Sridhar, V; Xiu, Zhang Zhen; Xu, Deng; Lee, Sung Hyo; Kim, Jin Kuk; Kang, Dong Jin; Bang, Dae-Suk

2009-03-01

Novel thermoplastic composites made from two major industrial and consumer wastes, fly ash and waste tire powder, have been developed. The effect of increasing fly ash loadings on performance characteristics such as tensile strength, thermal, dynamic mechanical and magnetic properties has been investigated. The morphology of the blends shows that fly ash particles have more affinity and adhesion towards the rubbery phase when compared to the plastic phase. The fracture surface of the composites shows extensive debonding of fly ash particles. Thermal analysis of the composites shows a progressive increase in activation energy with increase in fly ash loadings. Additionally, morphological studies of the ash residue after 90% thermal degradation shows extensive changes occurring in both the polymer and filler phases. The processing ability of the thermoplastics has been carried out in a Monsanto processability testing machine as a function of shear rate and temperature. Shear thinning behavior, typical of particulate polymer systems, has been observed irrespective of the testing temperatures. Magnetic properties and percolation behavior of the composites have also been evaluated.

Thermoresponsive electrospun fibers for water harvesting applications

NASA Astrophysics Data System (ADS)

Thakur, Neha; Baji, Avinash; Ranganath, Anupama Sargur

2018-03-01

Temperature triggered switchable cellulose acetate-poly(N-isopropylacrylamide) (CA-PNIPAM) core-shell and blend nanofibers are fabricated for controlled moisture harvesting applications. Core-shell fibers are fabricated using a co-axial electrospinning setup whereas the conventional electrospinning setup is employed for fabricating the blend fibers. Investigation of their wettability behaviour demonstrated that the blend fibers are superhydrophilic whereas the core-shell fibers are hydrophilic at ambient temperature. Furthermore, both the samples have an ability to switch between the two states viz. hydrophilic to hydrophobic state based on thermal stimulus. The core-shell fibers are shown to have higher moisture sorption ability compared to the blend fibers. This study investigates the mechanism behind the switchable wettability behaviour of the core-shell fibers and demonstrates the crucial role played by the functional groups present on the surface layer of fibers in governing their moisture collection efficiency.

Photophysics of charge transfer in a polyfluorene/violanthrone blend

NASA Astrophysics Data System (ADS)

Cabanillas-Gonzalez, J.; Virgili, T.; Lanzani, G.; Yeates, S.; Ariu, M.; Nelson, J.; Bradley, D. D. C.

2005-01-01

We present a study of the photophysical and photovoltaic properties of blends of violanthrone in poly[9, 9-bis (2-ethylhexyl)-fluorene-2, 7-diyl ] (PF2/6) . Photoluminescence quenching and photocurrent measurements show moderate efficiencies for charge generation, characteristic of such polymer/dye blends. Pump-probe measurements on blend films suggest that while ˜47% of the total exciton population dissociates within 4ps of photoexcitation, only ˜32% subsequently results in the formation of dye anions. We attribute the discrepancy to the likely formation of complex species with long lifetimes, such as stabilized interface charge pairs or exciplexes. This conclusion is supported by the appearance of a long lifetime component of 2.4ns in the dynamics of the photoinduced absorption signal associated to polarons in photoinduced absorption bands centered at 560nm .

Investigating the Influence of Waste Basalt Powder on Selected Properties of Cement Paste and Mortar

NASA Astrophysics Data System (ADS)

Dobiszewska, Magdalena; Beycioğlu, Ahmet

2017-10-01

Concrete is the most widely used man-made construction material in civil engineering applications. The consumption of cement and thus concrete, increases day by day along with the growth of urbanization and industrialization and due to new developments in construction technologies, population growing, increasing of living standard. Concrete production consumes much energy and large amounts of natural resources. It causes environmental, energy and economic losses. The most important material in concrete production is cement. Cement industry contributes to production of about 7% of all CO2 generated in the world. Every ton of cement production releases nearly one ton of CO2 to atmosphere. Thus the concrete and cement industry changes the environment appearance and influences it very much. Therefore, it has become very important for construction industry to focus on minimizing the environmental impact, reducing energy consumption and limiting CO2 emission. The need to meet these challenges has spurred an interest in the development of a blended Portland cement in which the amount of clinker is reduced and partially replaced with mineral additives - supplementary cementitious materials (SCMs). Many researchers have studied the possibility of using another mineral powder in mortar and concrete production. The addition of marble dust, basalt powder, granite or limestone powder positively affects some properties of cement mortar and concrete. This paper presents an experimental study on the properties of cement paste and mortar containing basalt powder. The basalt powder is a waste emerged from the preparation of aggregate used in asphalt mixture production. Previous studies have shown that analysed waste used as a fine aggregate replacement, has a beneficial effect on some properties of mortar and concrete, i.e. compressive strength, flexural strength and freeze resistance also. The present study shows the results of the research concerning the modification of cement paste and mortar with basalt powder. The modification consists in that the powder waste was added as partial replacement of cement. Four types of common cement were examined, i.e. CEM I, CEM II/A-S, CEM II/A-V and CEM II/B-V. The percentages of basalt powder in this research are 0%, 1%, 2%, 3%, 4%, 6%, 8% and 10% by mass. Results showed that the addition of basalt powder improved the strength of cement mortar. The use of mineral powder as the partial substitution of cement allows the effective management of industrial waste and improves some properties of cement mortar.

Copper Multiwall Carbon Nanotubes and Copper-Diamond Composites for Advanced Rocket Engines

NASA Technical Reports Server (NTRS)

Bhat, Biliyar N.; Ellis, Dave L.; Smelyanskiy, Vadim; Foygel, Michael; Singh, Jogender; Rape, Aaron; Vohra, Yogesh; Thomas, Vinoy; Li, Deyu; Otte, Kyle

2013-01-01

This paper reports on the research effort to improve the thermal conductivity of the copper-based alloy NARloy-Z (Cu-3 wt.%Ag-0.5 wt.% Zr), the state-of-the-art alloy used to make combustion chamber liners in regeneratively-cooled liquid rocket engines, using nanotechnology. The approach was to embed high thermal conductivity multiwall carbon nanotubes (MWCNTs) and diamond (D) particles in the NARloy-Z matrix using powder metallurgy techniques. The thermal conductivity of MWCNTs and D have been reported to be 5 to 10 times that of NARloy-Z. Hence, 10 to 20 vol. % MWCNT finely dispersed in NARloy-Z matrix could nearly double the thermal conductivity, provided there is a good thermal bond between MWCNTs and copper matrix. Quantum mechanics-based modeling showed that zirconium (Zr) in NARloy-Z should form ZrC at the MWCNT-Cu interface and provide a good thermal bond. In this study, NARloy-Z powder was blended with MWCNTs in a ball mill, and the resulting mixture was consolidated under high pressure and temperature using Field Assisted Sintering Technology (FAST). Microstructural analysis showed that the MWCNTs, which were provided as tangles of MWCNTs by the manufacturer, did not detangle well during blending and formed clumps at the prior particle boundaries. The composites made form these powders showed lower thermal conductivity than the base NARloy-Z. To eliminate the observed physical agglomeration, tangled multiwall MWCNTs were separated by acid treatment and electroless plated with a thin layer of chromium to keep them separated during further processing. Separately, the thermal conductivities of MWCNTs used in this work were measured, and the results showed very low values, a major factor in the low thermal conductivity of the composite. On the other hand, D particles embedded in NARloy-Z matrix showed much improved thermal conductivity. Elemental analysis showed migration of Zr to the NARloy-Z-D interface to form ZrC, which appeared to provide a low contact thermal resistance. These results are consistent with the quantum mechanics-based model predictions. NARloy-Z-D composites have relatively high thermal conductivities and are promising for further development.

Copper-Multiwall Carbon Nanotubes and Copper-Diamond Composites for Advanced Rocket Engines

NASA Technical Reports Server (NTRS)

Bhat, Biliyar N.; Ellis, Dave L.; Smelyanskiy, Vadim; Foygel, Michael; Rape, Aaron; Singh, Jogender; Vohra, Yogesh K.; Thomas, Vinoy; Otte, Kyle G.; Li, Deyu

2013-01-01

This paper reports on the research effort to improve the thermal conductivity of the copper-based alloy NARloy-Z (Cu-3 wt.%Ag-0.5 wt.% Zr), the state-of-the-art alloy used to make combustion chamber liners in regeneratively-cooled liquid rocket engines, using nanotechnology. The approach was to embed high thermal conductivity multiwall carbon nanotubes (MWCNTs) and diamond (D) particles in the NARloy-Z matrix using powder metallurgy techniques. The thermal conductivity of MWCNTs and D have been reported to be 5 to 10 times that of NARloy-Z. Hence, 10 to 20 vol. % MWCNT finely dispersed in NARloy-Z matrix could nearly double the thermal conductivity, provided there is a good thermal bond between MWCNTs and copper matrix. Quantum mechanics-based modeling showed that zirconium (Zr) in NARloy-Z should form ZrC at the MWCNT-Cu interface and provide a good thermal bond. In this study, NARloy-Z powder was blended with MWCNTs in a ball mill, and the resulting mixture was consolidated under high pressure and temperature using Field Assisted Sintering Technology (FAST). Microstructural analysis showed that the MWCNTs, which were provided as tangles of MWCNTs by the manufacturer, did not detangle well during blending and formed clumps at the prior particle boundaries. The composites made form these powders showed lower thermal conductivity than the base NARloy-Z. To eliminate the observed physical agglomeration, tangled multiwall MWCNTs were separated by acid treatment and electroless plated with a thin layer of chromium to keep them separated during further processing. Separately, the thermal conductivities of MWCNTs used in this work were measured, and the results showed very low values, a major factor in the low thermal conductivity of the composite. On the other hand, D particles embedded in NARloy-Z matrix showed much improved thermal conductivity. Elemental analysis showed migration of Zr to the NARloy-Z-D interface to form ZrC, which appeared to provide a low contact thermal resistance. These results are consistent with the quantum mechanics-based model predictions. NARloy-Z-D composites have relatively high thermal conductivities and are promising for further development.

Nanostructured conductive polymeric materials

NASA Astrophysics Data System (ADS)

Al-Saleh, Mohammed H.

Conductive polymer composites (CPCs) are a suitable alternative to metals in many applications due to their light-weight, corrosion resistance, low cost, ease of processing and design flexibility. CPCs have been formulated using different types of conductive fillers. In this PhD thesis, the focus is on CPCs for electrostatic discharge (ESD) protection and electromagnetic interference (EMI) attenuation. Despite the versatility of conductive fillers, carbon black (CB) has been the dominant filler to make CPCs for ESD protection applications because CB/polymer composites have a cost advantage over all other CPCs. For EMI shielding, stainless steel fibres and metal coated fibers are the preferred fillers, however CPCs made of those fibers are not the dominant EMI shielding materials. Metal coated and polymer plated polymers are the most widely used EMI shielding options. The limited use of CPCs in the EMI shielding market is because the high filler loading required to formulate a composite with an adequate level of shielding remarkably increases the composite price. In order to increase the competitiveness of CPCs, percolation threshold should be minimized as much as possible and composites with high EMI shielding capabilities at low filler loading should be formulated because all conductive fillers are expensive compared to polymers. In this thesis, two different methodologies to reduce percolation threshold in CPCs have been successfully developed and a CPC with exceptional EMI shielding capability has been formulated using copper nanowires as conductive filler. The first percolation threshold reduction technique is based on the selective localization of CB at the interface of immiscible polymer blend. The technique requires adding a copolymer that prefers the blend's interface and for which CB nanoparticles has the highest affinity. The second method is based on producing a CPC powder and then using this powder as a conductive filler to produce composite by dry mixing with pure polymer powder followed by compression molding. The EMI shielding material was developed using copper nanowires. CuNW/Polystyrene composites exhibit EMI shielding effectiveness exceeding that of metal microfillers and carbon nanotube/polymer composites and approaching that of coating techniques have been formulated by solution processing and dry mixing.

Ultrafast, efficient separations of large-sized dsDNA in a blended polymer matrix by microfluidic chip electrophoresis: A Design of Experiments approach

PubMed Central

Sun, Mingyun; Lin, Jennifer S.

2012-01-01

Double-stranded (ds) DNA fragments over a wide size range were successfully separated in blended polymer matrices by microfluidic chip electrophoresis. Novel blended polymer matrices composed of two types of polymers with three different molar masses were developed to provide improved separations of large dsDNA without negatively impacting the separation of small dsDNA. Hydroxyethyl celluloses (HECs) with average molar masses of ~27 kDa and ~1 MDa were blended with a second class of polymer, high-molar mass (~7 MDa) linear polyacrylamide (LPA). Fast and highly efficient separations of commercially available DNA ladders were achieved on a borosilicate glass microchip. A distinct separation of a 1 Kb DNA extension ladder (200 bp to 40,000 bp) was completed in 2 minutes. An orthogonal Design of Experiments (DOE) was used to optimize experimental parameters for DNA separations over a wide size range. We find that the two dominant factors are the applied electric field strength and the inclusion of a high concentration of low-molar mass polymer in the matrix solution. These two factors exerted different effects on the separations of small dsDNA fragments below 1 kbp, medium dsDNA fragments between 1 kbp and 10 kbp, and large dsDNA fragments above 10 kbp. PMID:22009451

Novel pH- and temperature-responsive blend hydrogel microspheres of sodium alginate and PNIPAAm-g-GG for controlled release of isoniazid.

PubMed

Kajjari, Praveen B; Manjeshwar, Lata S; Aminabhavi, Tejraj M

2012-12-01

This paper reports the preparation and characterization of novel pH- and thermo-responsive blend hydrogel microspheres of sodium alginate (NaAlg) and poly(N-isopropylacrylamide)(PNIPAAm)-grafted-guar gum (GG) i.e., PNIPAAm-g-GG by emulsion cross-linking method using glutaraldehyde (GA) as a cross-linker. Isoniazid (INZ) was chosen as the model antituberculosis drug to achieve encapsulation up to 62%. INZ has a plasma half-life of 1.5 h, whose release was extended up to 12 h. Fourier transform infrared spectroscopy was used to confirm the grafting reaction and chemical stability of INZ during the encapsulation. Differential scanning calorimetry was used to investigate the drug's physical state, while powder X-ray diffraction confirmed the molecular level dispersion of INZ in the matrix. Scanning electron microscopy confirmed varying surface morphologies of the drug-loaded microspheres. Temperature- and pH-responsive nature of the blend hydrogel microspheres were investigated by equilibrium swelling, and in vitro release experiments were performed in pH 1.2 and pH 7.4 buffer media at 37°C as well as at 25°C. Kinetics of INZ release was analyzed by Ritger-Peppas empirical equation to compute the diffusional exponent parameter (n), whose value ranged between 0.27 and 0.58, indicating the release of INZ follows a diffusion swelling controlled release mechanism.

Preparation of Pure and Stable Chitosan Nanofibers by Electrospinning in the Presence of Poly(ethylene oxide)

PubMed Central

Mengistu Lemma, Solomon; Bossard, Frédéric; Rinaudo, Marguerite

2016-01-01

Electrospinning was employed to obtain chitosan nanofibers from blends of chitosans (CS) and poly(ethylene oxide) (PEO). Blends of chitosan (MW (weight-average molecular weight) = 102 kg/mol) and PEO (M (molecular weight) = 1000 kg/mol) were selected to optimize the electrospinning process parameters. The PEO powder was solubilized into chitosan solution at different weight ratios in 0.5 M acetic acid. The physicochemical changes of the nanofibers were determined by scanning electron microscopy (SEM), swelling capacity, and nuclear magnetic resonance (NMR) spectroscopy. For stabilization, the produced nanofibers were neutralized with K2CO3 in water or 70% ethanol/30% water as solvent. Subsequently, repeated washings with pure water were performed to extract PEO, potassium acetate and carbonate salts formed in the course of chitosan nanofiber purification. The increase of PEO content in the blend from 20 to 40 w% exhibited bead-free fibers with average diameters 85 ± 19 and 147 ± 28 nm, respectively. Their NMR analysis proved that PEO and the salts were nearly completely removed from the nanostructure of chitosan, demonstrating that the adopted strategy is successful for producing pure chitosan nanofibers. In addition, the nanofibers obtained after neutralization in ethanol-aqueous solution has better structural stability, at least for six months in aqueous solutions (phosphate buffer (PBS) or water). PMID:27792192

The storage degradation of an 18650 commercial cell studied using neutron powder diffraction

NASA Astrophysics Data System (ADS)

Lee, Po-Han; Wu, She-huang; Pang, Wei Kong; Peterson, Vanessa K.

2018-01-01

Commercial 18650 lithium ion cells containing a blended positive electrode of layered LiNi0.5Mn0.3Co0.2O2 and spinel Li1.1Mn1.9O4 alongside a graphite negative electrode were stored at various depth-of-discharge (DoD) at 60 °C for 1, 2, 4, and 6 months. After storage, the cells were cycled at C/25 at 25 °C between 2.75 and 4.2 V for capacity determination and incremental capacity analysis (ICA). In addition to ICA analysis, the mechanism for capacity fade was investigated by combining the results of neutron powder diffraction under in-situ and operando conditions, in conjunction with post-mortem studies of the electrodes using synchrotron X-ray powder diffraction and inductively-coupled plasma optical emission spectroscopy. Among the cells, those stored at 25% DoD suffered the highest capacity fade due to their higher losses of active Li, NMC, and LMO than cells stored at other DoD. The cells stored at 0% DoD shows second high capacity fade because they exhibit the highest of active LMO and graphite anode among the stored cells and higher losses of active Li and NMC than cells stored at 50% DoD.

Processing of AlCoCrFeNiTi high entropy alloy by atmospheric plasma spraying

NASA Astrophysics Data System (ADS)

Löbel, M.; Lindner, T.; Kohrt, C.; Lampke, T.

2017-03-01

High Entropy Alloys (HEA) are gaining increasing interest due to their unique combination of properties. Especially the combination of high mechanical strength and hardness with distinct ductility makes them attractive for numerous applications. One interesting alloy system that exhibits excellent properties in bulk state is AlCoCrFeNiTi. A high strength, wear resistance and high-temperature resistance are the necessary requirements for the application in surface engineering. The suitability of blended, mechanically ball milled and inert gas atomized feedstock powders for the development of atmospheric plasma sprayed (APS) coatings is investigated in this study. The ball milled and inert gas atomized powders were characterized regarding their particle morphology, phase composition, chemical composition and powder size distribution. The microstructure and phase composition of the thermal spray coatings produced with different feedstock materials was investigated and compared with the feedstock material. Furthermore, the Vickers hardness (HV) was measured and the wear behavior under different tribological conditions was tested in ball-on-disk, oscillating wear and scratch tests. The results show that all produced feedstock materials and coatings exhibit a multiphase composition. The coatings produced with inert gas atomized feedstock material provide the best wear resistance and the highest degree of homogeneity.

Mechanism of amorphisation of micro-particles of griseofulvin during powder flow in a mixer.

PubMed

Pazesh, Samaneh; Höckerfelt, Mina Heidarian; Berggren, Jonas; Bramer, Tobias; Alderborn, Göran

2013-11-01

The purpose of the research was to investigate the degree of solid-state amorphisation during powder flow and to propose a mechanism for this transformation. Micro-particles of griseofulvin (about 2 μm in diameter) were mixed in a shear mixer under different conditions to influence the inter-particulate collisions during flow, and the degree of amorphisation was determined by micro-calorimeter. The amorphisation of griseofulvin particles (GPs) during repeated compaction was also determined. The GPs generally became disordered during mixing in a range from about 6% to about 86%. The degree of amorphisation increased with increased mixing time and increased batch size of the mixer, whereas the addition of a lubricant to the blend reduced the degree of amorphisation. Repeated compaction using the press with ejection mode gave limited amorphisation, whereas repeated compaction without an ejection process gave minute amorphisation. It is concluded that during powder flow, the most important inter-particulate contact process that cause the transformation of a crystalline solid into an amorphous state is sliding. On the molecular scale, this amorphisation is proposed to be caused by vitrification, that is the melting of a solid because of the generation of heat during sliding followed by solidification into an amorphous phase. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.

Equal channel angular pressing of powder processed Al6061/SiC nano metal matrix composites and study of its wear properties

NASA Astrophysics Data System (ADS)

Bongale, Arunkumar M.; Kumar, Satish

2018-03-01

Nano Metal Matrix Composites were fabricated by a novel approach by combining powder metallurgy and equal channel angular pressing (ECAP) using aluminium alloy 6061 (Al6061) as matrix phase and 2, 4 and 6 wt% of silicon carbide nanoparticles (SiCnp) as reinforcements. Alloying elements of Al6061 in their elemental form are blended together using high energy planetary ball mill and calculated wt% of SiCnp were mixed with it. Thus formed composite powder mixture is compacted in a uniaxial compaction die and then subjected to ECAP up to three passes. Density and porosity of samples were estimated using Archimedes’ principle. Pin on disc setup is used to evaluate the wear properties of the composites under different speed and loading conditions. Tests revealed that increase in wt% of SiCnp reduces the wear rate of the composites whereas increasing the load and speed increases wear rate of the composite samples. SEM micrographs of worn surfaces indicated different types of wear mechanism responsible for wear of the specimens under different testing conditions. Also, wt% of SiCnp and the number of passes through ECAP were found to increase the hardness value of the composite material.

[Preparation of freeze-dried powder of recombinate hirudin-2 nanoparticle for nasal delivery and permeability through nasal membrane in vitro].

PubMed

Chen, Ming-Xia; Zhang, Jian-Bao; Yu, Ji-Ping; Ye, Jing; Wei, Bao-Hong; Zhang, Yu-Jie

2013-06-01

To optimize the freeze-dried powder preparation technology of recombinate hirudin-2 (rHV2) nanoparticle which has bio-adhesive characteristic for nasal delivery, also to investigate its stability and permeability through nasal membrane in vitro. Taking the appearance, rediffusion of nanoparticle and rHV2 encapsulation efficiency as the evaluation indexes. Cryoprotector, the preparative technique and the effect of illumination and high temperature factors on its stability for rHV2 freeze-dried powder were investigated. Using Fraze diffusion cell technique, the permeability of rHV2 across rabbit nasal mucous membrane in chitosan solution, chitosan nanoparticle, and nanoparticle frozen-dried powder were compared with that in normal saline solution. The optimized preparation of rHV2 nanoparticle freeze-dried powder was as follows: 5% trehalose and glucose (1:1) was used as cryoprotector, nanoparticle solution was freezed for 24 h in vacuum frozen-dryer after being pre-freezed for 24 h. The content of rHV2 in the freeze-dried powder was 1.1 ug/mg. Illumination had little effect on the appearance, rediffusion and encapsulation efficiency of the rHV2 freeze-dried powder. High temperature could obviously influence the appearance of nanoparticle freeze-dried powder. The permeability coefficient (P) of nanoparticle was 5 times more than that in chictonson solution. It was indicated that chitosan nanoparticle has effect on increasing the permeability of rHV2. The freeze-dried powder of chitosan nanoparticle can be a good nasal preparation of rHV2.

Batch technique to evaluate the efficiency of different natural adsorbents for defluoridation from groundwater

NASA Astrophysics Data System (ADS)

Kumar, Pankaj; Saraswat, Chitresh; Mishra, Binaya Kumar; Avtar, Ram; Patel, Hiral; Patel, Asha; Sharma, Tejal; Patel, Roshni

2017-09-01

Fluoride pollution (with concentration >1.0 mg/L) in groundwater has become a global threat in the recent past due to the lesser availability of potable groundwater resource. In between several defluoridation techniques discovered so far, the adsorption process proved to be most economic and efficient. This study is an effort to evaluate defluoridation efficiency of powdered rice husk, fine chopped rice husk and sawdust by the batch adsorption process. Optimum defluoridation capacity is achieved by optimizing various parameters, viz. dose of adsorbent, pH, contact time and initial concentration. It was found that all three materials can be employed for the defluoridation technique, but powdered rice husk is the best adsorbent in the midst of all three. Powdered rice husk showed fluoride removal efficiency ranging between 85 and 90 % in the contact period of 7 h only in conditions of all optimized parameter. Following this parameter optimization, adsorption efficiency was also evaluated at natural pH of groundwater to minimize the cost of defluoridation. No significant difference was found between fluoride adsorption at optimized pH (pH = 4) and natural one (pH = 7), which concludes that powdered rice husk can be efficiently used for the defluoridation technique at field scale. The adsorption isotherm using this adsorbent perfectly followed Langmuir isotherms. The value of calculated separation factor also suggests the favourable adsorption of fluoride onto this adsorbent under the conditions used for the experiments. The field application for defluoridation of groundwater using this adsorbent (based on pH of natural groundwater there and seasonal variation of temperature) showed the high success rate.

Mixing of low-dose cohesive drug and overcoming of pre-blending step using a new gentle-wing high-shear mixer granulator.

PubMed

Alsulays, Bader B; Fayed, Mohamed H; Alalaiwe, Ahmed; Alshahrani, Saad M; Alshetaili, Abdullah S; Alshehri, Sultan M; Alanazi, Fars K

2018-05-16

The objective of this study was to examine the influence of drug amount and mixing time on the homogeneity and content uniformity of a low-dose drug formulation during the dry mixing step using a new gentle-wing high-shear mixer. Moreover, the study investigated the influence of drug incorporation mode on the content uniformity of tablets manufactured by different methods. Albuterol sulfate was selected as a model drug and was blended with the other excipients at two different levels, 1% w/w and 5% w/w at impeller speed of 300 rpm and chopper speed of 3000 rpm for 30 min. Utilizing a 1 ml unit side-sampling thief probe, triplicate samples were taken from nine different positions in the mixer bowl at selected time points. Two methods were used for manufacturing of tablets, direct compression and wet granulation. The produced tablets were sampled at the beginning, middle, and end of the compression cycle. An analysis of variance analysis indicated the significant effect (p < .05) of drug amount on the content uniformity of the powder blend and the corresponding tablets. For 1% w/w and 5% w/w formulations, incorporation of the drug in the granulating fluid provided tablets with excellent content uniformity and very low relative standard deviation (∼0.61%) during the whole tableting cycle compared to direct compression and granulation method with dry incorporation mode of the drug. Overall, gentle-wing mixer is a good candidate for mixing of low-dose cohesive drug and provides tablets with acceptable content uniformity with no need for pre-blending step.

Investigation on the gaseous and particulate emissions of a compression ignition engine fueled with diesel-dimethyl carbonate blends.

PubMed

Cheung, C S; Zhu, Ruijun; Huang, Zuohua

2011-01-01

The effect of dimethyl carbonate (DMC) on the gaseous and particulate emissions of a diesel engine was investigated using Euro V diesel fuel blended with different proportions of DMC. Combustion analysis shows that, with the blended fuel, the ignition delay and the heat release rate in the premixed combustion phase increase, while the total combustion duration and the fuel consumed in the diffusion combustion phase decrease. Compared with diesel fuel, with an increase of DMC in the blended fuel, the brake thermal efficiency is slightly improved but the brake specific fuel consumption increases. On the emission side, CO increases significantly at low engine load but decreases at high engine load while HC decreases slightly. NO(x) reduces slightly but the reduction is not statistically significant, while NO(2) increases slightly. Particulate mass and number concentrations decrease upon using the blended fuel while the geometric mean diameter of the particles shifts towards smaller size. Overall speaking, diesel-DMC blends lead to significant improvement in particulate emissions while the impact on CO, HC and NO(x) emissions is small. Copyright © 2010 Elsevier B.V. All rights reserved.

Competing Stereocomplexation and Homocrystallization of Poly(l-lactic acid)/Poly(d-lactic acid) Racemic Mixture: Effects of Miscible Blending with Other Polymers.

PubMed

Bao, Jianna; Xue, Xiaojia; Li, Kai; Chang, Xiaohua; Xie, Qing; Yu, Chengtao; Pan, Pengju

2017-07-20

Promoting the stereocomplexation ability of high-molecular-weight poly(l-lactic acid) (PLLA) and poly(d-lactic acid) (PDLA) is an efficient way to improve the thermal resistance of the resulting materials. Herein, we studied the competing crystallization kinetics, polymorphic crystalline structure, and lamellae structure of the PLLA/PDLA component in its miscible blends with poly(vinyl acetate) (PVAc) and proposed a method to improve the stereocomplexation ability of PLLA and PDLA through miscible blending with the other polymer. Crystallization of the PLLA/PDLA component is suppressed after the addition of PVAc, due to the dilution effect. The stereocomplexation ability of PLLA and PDLA is enhanced by blending with PVAc; this becomes more obvious at a high PVAc content (≥50 wt %) but less significant with the further increase of PLLA, PDLA molecular weights. Almost exclusive formation of SCs is achieved for PLLA and PDLA after blending with a large proportion of PVAc (e.g., 75 wt %). Incorporation of PVAc also facilitates the HC-to-SC structural reorganization upon heating. The increased chain mobility, decreased equilibrium melting point, and enhanced intermolecular interactions may account for the preferential stereocomplexation in PLLA/PDLA/PVAc blends.

Regulated and unregulated emissions from a diesel engine fueled with diesel fuel blended with diethyl adipate

NASA Astrophysics Data System (ADS)

Zhu, Ruijun; Cheung, C. S.; Huang, Zuohua; Wang, Xibin

2011-04-01

Experiments were carried out on a four-cylinder direct-injection diesel engine operating on Euro V diesel fuel blended with diethyl adipate (DEA). The blended fuels contain 8.1%, 16.4%, 25% and 33.8% by volume fraction of DEA, corresponding to 3%, 6%, 9% and 12% by mass of oxygen in the blends. The engine performance and exhaust gas emissions of the different fuels were investigated at five engine loads at a steady speed of 1800 rev/min. The results indicated an increase of brake specific fuel consumption and brake thermal efficiency when the engine was fueled with the blended fuels. In comparison with diesel fuel, the blended fuels resulted in an increase in hydrocarbon (HC) and carbon monoxide (CO), but a decrease in particulate mass concentrations. The nitrogen oxides (NO x) emission experienced a slight variation among the test fuels. In regard to the unregulated gaseous emissions, formaldehyde and acetaldehyde increased, while 1,3-butadiene, ethene, ethyne, propylene and BTX (benzene, toluene and xylene) in general decreased. A diesel oxidation catalyst (DOC) was found to reduce significantly most of the investigated unregulated pollutants when the exhaust gas temperature was sufficiently high.

Hydrothermal synthesis and characterization of hydroxyapatite and fluorhydroxyapatite nano-size powders.

PubMed

Montazeri, Leila; Javadpour, Jafar; Shokrgozar, Mohammad Ali; Bonakdar, Shahin; Javadian, Sayfoddin

2010-08-01

Pure hydroxyapatite (HAp) and fluoride-containing apatite powders (FHAp) were synthesized using a hydrothermal method. The powders were assessed by x-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscope (SEM) and F-selective electrode. X-ray diffraction results revealed the formation of single phase apatite structure for all the compositions synthesized in this work. However, the addition of a fluoride ion led to a systematic shift in the (3 0 0) peak of the XRD pattern as well as modifications in the FTIR spectra. It was found that the efficiency of fluoride ion incorporation decreased with the increase in the fluoride ion content. Fluorine incorporation efficiency was around 60% for most of the FHAp samples prepared in the current study. Smaller and less agglomerated particles were obtained by fluorine substitution. The bioactivity of the powder samples with different fluoride contents was compared by performing cell proliferation, alkaline phosphatase (ALP) and Alizarin red staining assays. Human osteoblast cells were used to assess the cellular responses to the powder samples in this study. Results demonstrated a strong dependence of different cell activities on the level of fluoridation.

Effect of IN718 Recycled Powder Reuse on Properties of Parts Manufactured by Means of Selective Laser Melting

NASA Astrophysics Data System (ADS)

Ardila, L. C.; Garciandia, F.; González-Díaz, J. B.; Álvarez, P.; Echeverria, A.; Petite, M. M.; Deffley, R.; Ochoa, J.

Powder quality control is essential to obtain parts with suitable mechanical properties in Selective Laser Melting manufacturing technique. One of the most important advantages of suchtechnique is that it allows an efficient use of the material, due to the possibility to recycle and reuse un-melted powder. Nevertheless, powder material properties may change due to repeated recycling, affecting this way the mechanicalbehavior of parts. In this paper the effect of powder reuse on its quality and on the mechanical properties of the resulting melted parts is studied via self-developed recycling methodology. The material considered for investigation was IN718, a nickel superalloy widely used in industry. After recycling powder up to 14 times, no significant changes were observed in powder and test parts properties. The results obtained in this work will help to validate powder recycling methodology for its use in current industrial Selective Laser Melting manufacturing.

Synthesis and improved explosion behaviors of aluminum powders coated with nano-sized nickel film

NASA Astrophysics Data System (ADS)

Kim, Kyung Tae; Kim, Dong Won; Kim, Soo Hyung; Kim, Chang Kee; Choi, Yoon Jeong

2017-09-01

Nickel (Ni) materials with a thickness of a few hundred nm were homogeneously coated on the surfaces of aluminum (Al) powders by an electroless plating process. The Ni-coated Al powders show characteristic interfacial structures mixed of Ni, Al and O instead of densely packed Al oxide at the surface. The explosion test of the Ni-coated Al powders utilizing flame ignition showed that the powders had a 3.6 times enhanced pressurization rate of 405 kPa/ms compared to 111 kPa/ms of uncoated Al powders. It was found that this is due to a feasible diffusion of oxygen atoms into the Al powders through the thin and rough interfacial layers present at the Ni/Al interface. These results clearly indicate that nano-sized Ni film introduced instead of surface oxide acts as a very profitable layer to achieve efficient combustion behaviors by a rapid oxidation of Al powders.

Effect of magnetite powder on anaerobic co-digestion of pig manure and wheat straw.

PubMed

Wang, Yanzi; Ren, Guangxin; Zhang, Tong; Zou, Shuzhen; Mao, Chunlan; Wang, Xiaojiao

2017-08-01

This study investigated the effects of different amounts of magnetite powder (i.e., 0g, 1.5g, 3g, 4.5g, 6g) on the anaerobic co-digestion of pig manure (PM) and wheat straw (WS). The variations in pH, alkalinity, cellulase activity (CEA), dehydrogenase activity (DHA) and methane production, were analyzed by phases. Correlation of the activities of the two enzymes with methane production was also analyzed, and the Gompertz model was used to evaluate the efficiency of anaerobic digestion (AD) with the addition of magnetite powder. The results showed that magnetite powder had significant effects on the anaerobic co-digestion of PM and WS. The maximum total methane production with the addition of 3g of magnetite powder was 195mL/g total solids (TS), an increase of 72.1%. The CEA and DHA increased with magnetite powder in the ranges of 1.5-4.5g, 1.5-6g, respectively, while the methane production showed a better correlation with DHA than with CEA. Using the Gompertz model, the efficiency of AD was optimal when adding 3g magnetite powder, with higher methane production potential (206mL/g TS), shorter lag-phase time (14.9d) and shorter AD period (44d). Copyright © 2017 Elsevier Ltd. All rights reserved.

Serious games and blended learning; effects on performance and motivation in medical education.

PubMed

Dankbaar, Mary

2017-02-01

More efficient, flexible training models are needed in medical education. Information technology offers the tools to design and develop effective and more efficient training. The aims of this thesis were: 1) Compare the effectiveness of blended versus classroom training for the acquisition of knowledge; 2) Investigate the effectiveness and critical design features of serious games for performance improvement and motivation. Five empirical studies were conducted to answer the research questions and a descriptive study on an evaluation framework to assess serious games was performed. The results of the research studies indicated that: 1) For knowledge acquisition, blended learning is equally effective and attractive for learners as classroom learning; 2) A serious game with realistic, interactive cases improved complex cognitive skills for residents, with limited self-study time. Although the same game was motivating for inexperienced medical students and stimulated them to study longer, it did not improve their cognitive skills, compared with what they learned from an instructional e‑module. This indicates an 'expertise reversal effect', where a rich learning environment is effective for experts, but may be contra-productive for novices (interaction of prior knowledge and complexity of format). A blended design is equally effective and attractive as classroom training. Blended learning facilitates adaptation to the learners' knowledge level, flexibility in time and scalability of learning. Games may support skills learning, provided task complexity matches the learner's competency level. More design-based research is needed on the effects of task complexity and other design features on performance improvement, for both novices and experts.

A blended design in acute care training: similar learning results, less training costs compared with a traditional format.

PubMed

Dankbaar, Mary E W; Storm, Diana J; Teeuwen, Irene C; Schuit, Stephanie C E

2014-09-01

Introduction There is a demand for more attractive and efficient training programmes in postgraduate health care training. This retrospective study aims to show the effectiveness of a blended versus traditional face-to-face training design. For nurses in postgraduate Acute and Intensive Care training, the effectiveness of a blended course design was compared with a traditional design. Methods In a first pilot study 57 students took a traditional course (2-h lecture and 2-h workshop) and 46 students took a blended course (2-h lecture and 2-h online self-study material). Test results were compared for both groups. After positive results in the pilot study, the design was replicated for the complete programme in Acute and Intensive Care. Now 16 students followed the traditional programme (11 days face-to-face education) and 31 students did the blended programme (7 days face-to-face and 40 h online self-study). An evaluation was done after the pilot and course costs were calculated. Results Results show that the traditional and blended groups were similar regarding the main characteristics and did not differ in learning results for both the pilot and the complete programme. Student evaluations of both designs were positive; however, the blended group were more confident that they had achieved the learning objectives. Training costs were reduced substantially. Conclusion The blended training design offers an effective and attractive training solution, leading to a significant reduction in costs.

Biodegradable-Polymer-Blend-Based Surgical Sealant with Body-Temperature-Mediated Adhesion.

PubMed

Behrens, Adam M; Lee, Nora G; Casey, Brendan J; Srinivasan, Priya; Sikorski, Michael J; Daristotle, John L; Sandler, Anthony D; Kofinas, Peter

2015-12-22

The development of practical and efficient surgical sealants has the propensity to improve operational outcomes. A biodegradable polymer blend is fabricated as a nonwoven fiber mat in situ. After direct deposition onto the tissue of interest, the material transitions from a fiber mat to a film. This transition promotes polymer-substrate interfacial interactions leading to improved adhesion and surgical sealant performance. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Corn-Soy-Blend Fortified with Phosphorus to Prevent Refeeding Hypophosphatemia in Undernourished Piglets

PubMed Central

Hother, Anne-Louise; Lykke, Mikkel; Martinussen, Torben; Poulsen, Hanne Damgaard; Mølgaard, Christian; Sangild, Per Torp; Briend, André; Hansen, Christian Fink; Friis, Henrik; Michaelsen, Kim F.; Thymann, Thomas

2017-01-01

Background Phosphorus (P) levels in refeeding diets are very important as undernourished children are at risk of hypophosphatemia during refeeding. For this reason, conventional corn-soy-blends (CSB) have been reformulated by the World Food Programme to obtain a mono-calcium-phosphate fortified product (CSB+) and a product further fortified with skim milk powder (CBS++). Methods Using a piglet model of undernourished children, we hypothesized that feeding of CSB+, CSB++ or CSB+ with added whey permeate (CSB+/wp) would help to prevent refeeding hypophosphatemia. Pigs were weaned at 4 weeks of age and undernutrition was induced with a nutritionally inadequate pure maize diet for 7 weeks, after which they were refed for 3 weeks with either CSB+ (n = 10), CSB++ (n = 10) or CSB+/wp (n = 10). For reference, a fourth group continued on the maize diet (REF, n = 10). Results Following induction of undernutrition, body weight and length were 29±5% and 67±4% (means±SD) of values in age-matched pigs fed a nutritionally adequate diet, and the mean serum P level was 1.77±0.34 mmol/l. During the first week of refeeding, P levels in the CSB+ pigs decreased to 55% of values before refeeding (P < 0.05) while values in the CSB++ and CSB+/wp pigs were able to maintain their plasma phosphate at a similar level as before refeeding. Conclusion We conclude that fortification of CSB with only monocalcium-phosphate does not prevent hypophosphatemia. Dairy products like skim milk powder or whey permeate may represent relevant sources of phosphorus during refeeding. The content and form of phosphorus in such diets need to be carefully evaluated, and the undernourished piglet may be used to test the efficacy of such diets. PMID:28081252

Corn-Soy-Blend Fortified with Phosphorus to Prevent Refeeding Hypophosphatemia in Undernourished Piglets.

PubMed

Hother, Anne-Louise; Lykke, Mikkel; Martinussen, Torben; Poulsen, Hanne Damgaard; Mølgaard, Christian; Sangild, Per Torp; Briend, André; Hansen, Christian Fink; Friis, Henrik; Michaelsen, Kim F; Thymann, Thomas

2017-01-01

Phosphorus (P) levels in refeeding diets are very important as undernourished children are at risk of hypophosphatemia during refeeding. For this reason, conventional corn-soy-blends (CSB) have been reformulated by the World Food Programme to obtain a mono-calcium-phosphate fortified product (CSB+) and a product further fortified with skim milk powder (CBS++). Using a piglet model of undernourished children, we hypothesized that feeding of CSB+, CSB++ or CSB+ with added whey permeate (CSB+/wp) would help to prevent refeeding hypophosphatemia. Pigs were weaned at 4 weeks of age and undernutrition was induced with a nutritionally inadequate pure maize diet for 7 weeks, after which they were refed for 3 weeks with either CSB+ (n = 10), CSB++ (n = 10) or CSB+/wp (n = 10). For reference, a fourth group continued on the maize diet (REF, n = 10). Following induction of undernutrition, body weight and length were 29±5% and 67±4% (means±SD) of values in age-matched pigs fed a nutritionally adequate diet, and the mean serum P level was 1.77±0.34 mmol/l. During the first week of refeeding, P levels in the CSB+ pigs decreased to 55% of values before refeeding (P < 0.05) while values in the CSB++ and CSB+/wp pigs were able to maintain their plasma phosphate at a similar level as before refeeding. We conclude that fortification of CSB with only monocalcium-phosphate does not prevent hypophosphatemia. Dairy products like skim milk powder or whey permeate may represent relevant sources of phosphorus during refeeding. The content and form of phosphorus in such diets need to be carefully evaluated, and the undernourished piglet may be used to test the efficacy of such diets.

A review on the engine performance and exhaust emission characteristics of diesel engines fueled with biodiesel blends.

PubMed

Damanik, Natalina; Ong, Hwai Chyuan; Tong, Chong Wen; Mahlia, Teuku Meurah Indra; Silitonga, Arridina Susan

2018-06-01

Biodiesels have gained much popularity because they are cleaner alternative fuels and they can be used directly in diesel engines without modifications. In this paper, a brief review of the key studies pertaining to the engine performance and exhaust emission characteristics of diesel engines fueled with biodiesel blends, exhaust aftertreatment systems, and low-temperature combustion technology is presented. In general, most biodiesel blends result in a significant decrease in carbon monoxide and total unburned hydrocarbon emissions. There is also a decrease in carbon monoxide, nitrogen oxide, and total unburned hydrocarbon emissions while the engine performance increases for diesel engines fueled with biodiesels blended with nano-additives. The development of automotive technologies, such as exhaust gas recirculation systems and low-temperature combustion technology, also improves the thermal efficiency of diesel engines and reduces nitrogen oxide and particulate matter emissions.

Effects of anticaking agents and relative humidity on the physical and chemical stability of powdered vitamin C.

PubMed

Lipasek, Rebecca A; Taylor, Lynne S; Mauer, Lisa J

2011-09-01

Vitamin C is an essential nutrient that is widely used by the food industry in the powder form for both its nutritional and functional properties. However, vitamin C is deliquescent, and deliquescence has been linked to physical and chemical instabilities. Anticaking agents are often added to powder systems to delay or prevent caking, but little is known about their effect on the chemical stability of powders. In this study, various anticaking agents (calcium phosphate, calcium silicate, calcium stearate, corn starch, and silicon dioxide) were combined with sodium ascorbate at 2% and 50% w/w ratios and stored at various relative humidities (23%, 43%, 64%, 75%, 85%, and 98% RHs). Chemical and physical stability and moisture sorption were monitored over time. Additionally, saturated solution samples were stored at various pHs to determine the effect of surface pH and dissolution on the vitamin degradation rate. Storage RH, time, and anticaking agent type and ratio all significantly affected (P < 0.05) moisture sorption and vitamin C stability. Silicon dioxide and calcium silicate (50% w/w) and calcium stearate (at both ratios) were the only anticaking agents to improve the physical stability of powdered sodium ascorbate while none of the anticaking agents improved its chemical stability. However, corn starch and calcium stearate had the least adverse effect on chemical stability. Dissolution rate and pH were also important factors affecting the chemical and physical stability of the powders. Therefore, monitoring storage environmental conditions and anticaking agent usage are important for understanding the stability of vitamin C. Anticaking agent type and ratio significantly affected the physical and chemical stability of vitamin C over time and over a range of RHs. No anticaking agent improved the chemical stability of the vitamin, and most caused an increase in chemical degradation even if physical stability was improved. It is possible that anticaking agents would greatly affect other chemically labile deliquescent ingredients, and therefore, anticaking agent usage and storage conditions should be monitored in blended powder systems. © 2011 Institute of Food Technologists®

Short communication: investigating the effect of saffron (Crocus sativus L.) nano-sizing on its colour extraction efficiency: a preliminary study.

PubMed

Abootalebian, Mehrdad; Karbasi, Maryam; Sadeghi, Maliheh; Abdinian, Mahnaz; Polikarpov, Igor

2017-10-01

This study investigated the effect of saffron nano-sizing on its the colour extraction yield. The whole stigma was ball-milled at three different times (10, 20 and 100 h), immediately or with a 24 h delay was submitted to absorption test, and then the colour extraction efficiency was determined. When stigma was milled for 100 h, its particle size was reduced to less than 20 nm, as shown by SEM and TEM images, and its extraction efficiency was considerably increased by 19.8% as compared with the stigma blended for 10 min. However with a 24 h delay between the end of milling and absorption test, the yield of colour extraction significantly decreased. The recommended milling conditions resulting in extraction efficiency of 16.2% (in comparison with stigma blended for 10 min) were determined to be the milling for 10 h with initial tendering prior to milling operation.

Highly efficient low color temperature organic LED using blend carrier modulation layer

NASA Astrophysics Data System (ADS)

Hsieh, Yao-Ching; Chen, Szu-Hao; Shen, Shih-Ming; Wang, Ching-Chiun; Chen, Chien-Chih; Jou, Jwo-Huei

2012-10-01

Color temperature (CT) of light has great effect on human physiology and psychology, and low CT light, minimizing melatonin suppression and decreasing the risk of breast, colorectal, and prostate cancer. We demonstrates the incorporation of a blend carrier modulation interlayer (CML) between emissive layers to improve the device performance of low CT organic light emitting diodes, which exhibits an external quantum efficiency of 22.7% and 36 lm W-1 (54 cd A-1) with 1880 K at 100 cd m-2, or 20.8% and 29 lm W-1 (50 cd A-1) with 1940 K at 1000 cd m-2. The result shows a CT much lower than that of incandescent bulbs, which is 2500 K with 15 lmW-1 efficiency, and even as low as that of candles, which is 2000 K with 0.1 lmW-1. The high efficiency of the proposed device may be attributed to its CML, which helps effectively distribute the entering carriers into the available recombination zones.

Production of drug nanosuspensions: effect of drug physical properties on nanosizing efficiency.

PubMed

Liu, Tao; Müller, Rainer H; Möschwitzer, Jan P

2018-02-01

Drug nanosuspension is one of the established methods to improve the bioavailability of poorly soluble drugs. Drug physical properties aspect (morphology, solid state, starting size et al) is a critical parameter determining the production efficiency. Some drug modification approaches such as spray-drying were proved to improve the millability of drug powders. However, the mechanism behind those improved performances is unclear. This study is to systematically investigate the influence of those physical properties. Five different APIs (active pharmaceutical ingredients) with different millabilities, i.e. resveratrol, hesperetin, glibenclamide, rutin, and quercetin, were processed by standard high pressure homogenization (HPH), wet bead milling (WBM), and a combinative method of spray-drying and HPH. Smaller starting sizes of certain APIs could accelerate the particle size reduction velocity during both HPH and WBM processes. Spherical particles were observed for almost all spray-dried powders (except spray-dried hesperetin) after spray-drying. The crystallinity of some spray-dried samples such as rutin and glibenclamide became much lower than their corresponding unmodified powders. Almost all spray-dried drug powders after HPH processes could lead to smaller nanocrystal particle size than unmodified APIs. The modified microstructure instead of solid state after spray-drying explained the potential reason for improved nanosizing efficiency. In addition, the contribution of starting size on the production efficiency was also critical according to both HPH and WBM results.

Gas atomization processing of tin and silicon modified LaNi 5 for nickel-metal hydride battery applications

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

Ting, Jason

1999-02-12

Numerous researchers have studied the relevant material properties of so-called AB 5 alloys for battery applications. These studies involved LaNi 5 substituted alloys which were prepared using conventional cast and crush alloying techniques. While valuable to the understanding of metal hydride effects, the previous work nearly ignored the potential for alternative direct powder production methods, like high pressure gas atomization (HPGA). Thus, there is a need to understand the relationship between gas atomization processes, powder particle solidification phases, and hydrogen absorption properties of ultra fine (< 25 μm) atomized powders with high surface area for enhanced battery performance. Concurrently, developmentmore » of a gas atomization nozzle that is more efficient than all current designs is needed to increase the yield of ultrafine AB 5 alloy powder for further processing advantage. Gas atomization processing of the AB 5 alloys was demonstrated to be effective in producing ultrafine spherical powders that were resilient to hydrogen cycling for the benefit of improving corrosion resistance in battery application. These ultrafine powders benefited from the rapid solidification process by having refined solute segregation in the microstructure of the gas atomized powders which enabled a rapid anneal treatment of the powders. The author has demonstrated the ability to produce high yields of ultrafine powder efficiently and cost effectively, using the new HPGA-III technology. Thus, the potential benefits of processing AB 5 alloys using the new HPGA technology could reduce manufacturing cost of nickel-metal hydride powder. In the near future, the manufacture of AB 5 alloy powders could become a continuous and rapid production process. The economic benefit of an improved AB 5 production process may thereby encourage the use of nickel-metal hydride rechargeable batteries in electrical vehicle applications in the foreseeable future.« less

Drug Release Studies from Caesalpinia pulcherrima Seed Polysaccharide.

PubMed

Jeevanandham, Somasundaram; Dhachinamoorthi, Duraiswamy; Bannoth Chandra Sekhar, Kothapalli

2011-01-01

This study examines the controlled release behavior of both water-soluble (acetaminophen, caffeine, theophylline and salicylic acid) and water insoluble (indomethacin) drugs derived from Caesalpinia pulcherrima seed Gum isolated from Caesalpinia pulcherrima kernel powder. It further investigates the effect of incorporating diluents such as microcrystalline cellulose and lactose on caffeine release. In addition the effect the gum's (polysaccharide) partial cross-linking had on release of acetaminophen was examined. Applying the exponential equation, the soluble drugs mechanism of release was found to be anomalous. The insoluble drugs showed a near case II or zero order release mechanism. The rate of release in descending order was caffeine, acetaminophen, theophylline, salicylic acid and indomethacin. An increase in the release kinetics of the drug was observed on blending with diluents. However, the rate of release varied with the type and amount of blend within the matrix. The mechanism of release due to effect of diluents was found to be anomalous. The rate of drug release decreased upon partial cross-linking and the mechanism of release was found to be of super case II.

A method for increase abrasive wear resistance parts by obtaining on methods casting on gasifying models

NASA Astrophysics Data System (ADS)

Sedukhin, V. V.; Anikeev, A. N.; Chumanov, I. V.

2017-11-01

Method optimizes hardening working layer parts’, working in high-abrasive conditions looks in this work: bland refractory particles WC and TiC in respect of 70/30 wt. % prepared by beforehand is applied on polystyrene model in casting’ mould. After metal poured in mould, withstand for crystallization, and then a study is carried out. Study macro- and microstructure received samples allows to say that thickness and structure received hardened layer depends on duration interactions blend harder carbides and liquid metal. Different character interactions various dispersed particles and matrix metal observed under the same conditions. Tests abrasive wear resistance received materials of method calculating residual masses was conducted in laboratory’ conditions. Results research wear resistance showed about that method obtaining harder coating of blend carbide tungsten and carbide titanium by means of drawing on surface foam polystyrene model before moulding, allows receive details with surface has wear resistance in 2.5 times higher, than details of analogy steel uncoated. Wherein energy costs necessary for transformation units mass’ substances in powder at obtained harder layer in 2.06 times higher, than materials uncoated.

Hydration studies of calcium sulfoaluminate cements blended with fly ash

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

García-Maté, M.; De la Torre, A.G.; León-Reina, L.

The main objective of this work is to study the hydration and properties of calcium sulfoaluminate cement pastes blended with fly ash (FA) and the corresponding mortars at different hydration ages. Laboratory X-ray powder diffraction, rheological studies, thermal analysis, porosimetry and compressive strength measurements were performed. The analysis of the diffraction data by Rietveld method allowed quantifying crystalline phases and overall amorphous contents. The studied parameters were: i) FA content, 0, 15 and 30 wt.%; and ii) water addition, water-to-CSA mass ratio (w/CSA = 0.50 and 0.65), and water-to-binder mass ratio (w/b = 0.50). Finally, compressive strengths after 6 monthsmore » of 0 and 15 wt.% FA [w/CSA = 0.50] mortars were similar: 73 ± 2 and 72 ± 3 MPa, respectively. This is justified by the filler effect of the FA as no strong evidences of reactivity of FA with CSA were observed. These results support the partial substitution of CSA cements with FA with the economic and environmental benefits.« less

Grinding Si3N4 Powder In Si3N4 Equipment

NASA Technical Reports Server (NTRS)

Herbell, Thomas P.; Freedman, Marc R.; Kiser, James D.

1989-01-01

Three methods of grinding compared. Report based on study of grinding silicon nitride powder in preparation for sintering into solid ceramic material. Attrition, vibratory, and ball mills lined with reaction-bonded silicon nitride tested. Rates of reduction of particle sizes and changes in chemical compositions of powders measured so grinding efficiences and increases in impurity contents from wear of mills and media evaluated for each technique.

Applicability of the mixture of bituminous coal and anthracite to conventional pulverized coal firing boiler

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

Takano, Shin-Ichi; Kiga, Takashi; Miyamae, Shigehiro

1994-12-31

In some future, it is expected for Japanese power stations to be hard to get a high-grade coal like a bituminous coal. We conducted therefore pilot scale tests of pulverized blends of bituminous coal and anthracite using a 1.2MWt tunnel furnace in order to evaluate the applicability of the blends of bituminous coal and anthracite to conventional pulverized coal firing boilers. One kind of bituminous coal and two kinds of anthracite, one was of low ash content and another was of high ash content, were prepared for the test. Previously to pilot scale tests, coal properties and ash properties ofmore » the blends of bituminous coal and anthracite were analyzed to estimate the characteristics of combustion, ash deposition, and so on. In the test, we investigated the combustion efficiency, NOx emission, characteristics of ignition stability and grindability changing the blend rate of anthracite. Results of our study indicated that the critical restrictions on the blending rate of anthracite were unburnt carbon in fly ash and NOx emission as for coals tested. The acceptable limitation on blending rate of anthracite was 10 and 20%, respectively for two kinds of conventional pulverized coal fired boiler. Concerning to the grindability, it became worse with increasing the blending rate of anthracite from grindability test using a roller mill, while it became better estimating from HGI.« less

Long-lived exciplex formation and delayed exciton emission in bulk heterojunction blends of silole derivative and polyfluorene copolymer: the role of morphology on exciplex formation and charge separation.

PubMed

Benson-Smith, Jessica J; Wilson, Joanne; Dyer-Smith, Clare; Mouri, Kazuhiro; Yamaguchi, Shigehiro; Murata, Hideyuki; Nelson, Jenny

2009-06-04

Long-lived exciplex emission is observed in blend films of poly[9,9-dioctylfluorene-co-N-(4-methoxy-phenyl)diphenylamine] (TFMO) and the soluble silole derivative 2,5-bis-(2,2-bipyridin-6-yl)-1,1-dimethyl-3,4-diphenylsilacyclopentadiene (PyPySPyPy). The exciplex is characterized by a long-lived (approximately 40-90 ns) component in both the photoluminescence and electroluminescence spectra, which is red-shifted relative to the emission of the pristine materials. In addition to exciplex emission, delayed fluorescence from the TFMO singlet state is observed and is attributed to exciton regeneration through the interfacial exciplex state. Comparing blend films made using chlorobenzene and p-xylene solvents, we find that exciplex lifetime and exciton regeneration in the blend film are sensitive to the choice of solvent and the resulting morphology of the blend film. The exciplex emissive lifetime can be correlated to changes in photoluminescence quenching and efficiency of light-emitting diodes.

Phase equilibria in polymer-blend thin films

NASA Astrophysics Data System (ADS)

Clarke, Nigel; Souche, Mireille

2010-03-01

To describe equilibrium concentration profiles in thin films of polymer mixtures, we propose a Hamiltonian formulation of the Flory-Huggins-de Gennes theory describing a polymer blend thin film. We first focus on the case of 50:50 polymer blends confined between anti-symmetric walls. The different phases of the system and the transitions between them, including finite size effects, are systematically studied through their relation with the geometry of the Hamiltonian flow in phase space. This method provides an easy and efficient way, with strong graphical insight, to infer the qualitative physical behavior of polymer blend thin films. The addition of a further degree of freedom in the system, namely a solvent, may result in a chaotic behavior of the system, characterized by the existence of solutions with exponential sensitivity to initial conditions. Such solutions and there subsequent contribution to the out-of-equilibrium dynamics of the system are well described in Hamiltonian formalism. A fully consistent treatment of the Flory-Huggins-de Gennes theory of thin film polymer blend solutions, in the spirit of the Hamiltonian approach will be presented. 1. M. Souche and N. Clarke, J. Chem. Phys., submitted.