Some aspects of the damage kinetics at static loading of a heterogeneous solid under the conditions of constrained deformation

NASA Astrophysics Data System (ADS)

Leksovskii, A. M.; Baskin, B. L.; Yakushev, P. N.

2015-12-01

The damaging kinetics of a composite system subjected to static loading, which simulates an inhomogeneous body with microductility, and of D16T-B(43%) composite simulating a quasi-brittle solid is analyzed with the acoustic emission method. By using laser interferometry, it is shown on a model sample that mesocracking may cause a short-term change in the plastic strain rate, which two or more orders of magnitude exceeds the change in the creep rate during the usual supramolecular structure reconfiguration. Whether the object will remain functional or acquire damage of the next scale after being subjected to such local "impact" loading depends on the ability of its immediate environment to absorb released energy.

Synergistic co-digestion of solid-organic-waste and municipal-sewage-sludge: 1 plus 1 equals more than 2 in terms of biogas production and solids reduction.

PubMed

Aichinger, Peter; Wadhawan, Tanush; Kuprian, Martin; Higgins, Matthew; Ebner, Christian; Fimml, Christian; Murthy, Sudhir; Wett, Bernhard

2015-12-15

Making good use of existing water infrastructure by adding organic wastes to anaerobic digesters improves the energy balance of a wastewater treatment plant (WWTP) substantially. This paper explores co-digestion load limits targeting a good trade-off for boosting methane production, and limiting process-drawbacks on nitrogen-return loads, cake-production, solids-viscosity and polymer demand. Bio-methane potential tests using whey as a model co-substrate showed diversification and intensification of the anaerobic digestion process resulting in a synergistical enhancement in sewage sludge methanization. Full-scale case-studies demonstrate organic co-substrate addition of up to 94% of the organic sludge load resulted in tripling of the biogas production. At organic co-substrate addition of up to 25% no significant increase in cake production and only a minor increase in ammonia release of ca. 20% have been observed. Similar impacts were measured at a high-solids digester pilot with up-stream thermal hydrolyses where the organic loading rate was increased by 25% using co-substrate. Dynamic simulations were used to validate the synergistic impact of co-substrate addition on sludge methanization, and an increase in hydrolysis rate from 1.5 d(-1) to 2.5 d(-1) was identified for simulating measured gas production rate. This study demonstrates co-digestion for maximizing synergy as a step towards energy efficiency and ultimately towards carbon neutrality. Copyright © 2015 Elsevier Ltd. All rights reserved.

Meso and micro-scale response of post carbon removal nitrifying MBBR biofilm across carrier type and loading.

PubMed

Young, Bradley; Banihashemi, Bahman; Forrest, Daina; Kennedy, Kevin; Stintzi, Alain; Delatolla, Robert

2016-03-15

This study investigates the effects of three specific moving bed biofilm reactor (MBBR) carrier types and two surface area loading rates on biofilm thickness, morphology and bacterial community structure of post carbon removal nitrifying MBBR systems along with the effects of carrier type and loading on ammonia removal rates and effluent solids settleability. The meso and micro analyses show that the AOB kinetics vary based on loading condition, but irrespective of carrier type. The meso-scale response to increases in loading was shown to be an increase in biofilm thickness with higher surface area carriers being more inclined to develop and maintain thicker biofilms. The pore spaces of these higher surface area to volume carriers also demonstrated the potential to become clogged at higher loading conditions. Although the biofilm thickness increased during higher loading conditions, the relative percentages of both the embedded viable and non-viable cells at high and conventional loading conditions remained stable; indicating that the reduced ammonia removal kinetics observed during carrier clogging events is likely due to the observed reduction in the surface area of the attached biofilm. Microbial community analyses demonstrated that the dominant ammonia oxidizing bacteria for all carriers is Nitrosomonas while the dominant nitrite oxidizing bacteria is Nitrospira. The research showed that filamentous species were abundant under high loading conditions, which likely resulted in the observed reduction in effluent solids settleability at high loading conditions as opposed to conventional loading conditions. Although the settleability of the effluent solids was correlated to increases in abundances of filamentous organisms in the biofilm, analyzed using next generation sequencing, the ammonia removal rate was not shown to be directly correlated to specific meso or micro-scale characteristics. Instead post carbon removal MBBR ammonia removal kinetics were shown to be related to the viable AOB cell coverage of the carriers; which was calculated by normalizing the surface area removal rate by the biofilm thickness, the bacterial percent abundance of ammonia oxidizing bacteria and the percentage of viable cells. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fate and mobility of pharmaceuticals in solid matrices.

PubMed

Drillia, Panagiota; Stamatelatou, Katerina; Lyberatos, Gerasimos

2005-08-01

The sorption and mobility of six pharmaceuticals were investigated in two soil types with different organic carbon and clay content, and in bacterial biomass (aerobic and anaerobic). The pharmaceuticals examined were carbamazepine, propranolol, diclofenac sodium, clofibric acid, sulfamethoxazole and ofloxacin. The sorption experiments were performed according to the OECD test Guideline 106. The distribution coefficients determined by this batch equilibrium method varied with the pharmaceutical tested and the solid matrix type. Ofloxacin was particularly strongly adsorbed (except of the case of using anaerobic biomass for the solid matrix) while clofibric acid was found to be weakly adsorbed. The fate of pharmaceuticals in soil was also assessed using lysimeters. Important parameters that were studied were: the pharmaceutical loading rate and the hydraulic loading rate for adsorption and the rate and duration of a "rain" event for desorption. Major differences in the mobility of the six pharmaceuticals were observed and correlated with the adsorption/desorption properties of the compounds.

High solids co-digestion of food and landscape waste and the potential for ammonia toxicity.

PubMed

Drennan, Margaret F; DiStefano, Thomas D

2014-07-01

A pilot-scale study was completed to determine the feasibility of high-solids anaerobic digestion (HSAD) of a mixture of food and landscape wastes at a university in central Pennsylvania (USA). HSAD was stable at low loadings (2g COD/L-day), but developed inhibitory ammonia concentrations at high loadings (15 g COD/L-day). At low loadings, methane yields were 232 L CH4/kg COD fed and 229 L CH4/kg VS fed, and at high loadings yields were 211 L CH4/kg COD fed and 272 L CH4/kg VS fed. Based on characterization and biodegradability studies, food waste appears to be a good candidate for HSAD at low organic loading rates; however, the development of ammonia inhibition at high loading rates suggests that the C:N ratio is too low for use as a single substrate. The relatively low biodegradability of landscape waste as reported herein made it an unsuitable substrate to increase the C:N ratio. Codigestion of food waste with a substrate high in bioavailable carbon is recommended to increase the C:N ratio sufficiently to allow HSAD at loading rates of 15 g COD/L-day. Copyright © 2014 Elsevier Ltd. All rights reserved.

Performance of a stratified sand filter in removal of chemical oxygen demand, total suspended solids and ammonia nitrogen from high-strength wastewaters.

PubMed

Healy, M G; Rodgers, M; Mulqueen, J

2007-06-01

A stratified sand filter column, operated in recirculation mode and treating synthetic effluent resembling high-strength dairy wastewaters was studied over a 342-d duration. The aim of this paper was to examine the organic, total suspended solids (TSS) and nutrient removal rates of the sand filter, operated in recirculation mode, under incrementally increasing hydraulic and organic loading rates and to propose a field filter-sizing criterion. Best performance was obtained at a system hydraulic loading rate of 10 L m(-2) d(-1); a higher system hydraulic loading rate (of 13.4 L m(-2) d(-1)) caused surface ponding. The system hydraulic loading rate of 10 L m(-2) d(-1) gave a filter chemical oxygen demand (COD), TSS, and total kjeldahl nitrogen (TKN) loading rate of 14, 3.7, and 2.1 g m(-2) d(-1), respectively, and produced consistent COD and TSS removals of greater than 99%, and an effluent NO(3)-N concentration of 42 mg L(-1) (accounting for an 86% reduction in total nitrogen (Tot-N)). As the proportional surface area requirement for the sand filter described in this study is less than the recommended surface area requirement of a free-water surface (FWS) wetland treating an effluent of similar quality, it could provide an economic and sustainable alternative to conventional wetland treatment.

Effect of Food Waste Co-Digestion on Digestion, Dewatering, and Cake Quality.

PubMed

Higgins, Matthew; Rajagopalan, Ganesh; Miller, Andre; Brown, Jeffrey; Beightol, Steven

2017-01-01

  The objective of this study was to evaluate the effect of food waste addition on anaerobic digestion performance as well as downstream parameters including dewatering, cake quality, and filtrate quality. Laboratory-scale digesters were fed processed food waste at rates of 25%, 45%, and 65% increased chemical oxygen demand (COD) loading rates compared to a control fed only primary and secondary solids. The specific methane yield increased from 370 L CH4/kg VSadded for the control to 410, 440, and 470 L CH4/kg VSadded for the 25, 45, and 65% food waste addition, respectively. The cake solids after dewatering were all higher for the food waste digesters compared to the control, with the highest cake solids being measured for the 45% food-waste loading. Compared to the control digester, the biosolids odorant concentration increased for the lowest dose of food waste. Odorant concentrations were below detection for the highest food waste loading.

Thermophilic co-digestion feasibility of distillers grains and swine manure: effect of C/N ratio and organic loading rate during high solid anaerobic digestion (HSAD).

PubMed

Sensai, P; Thangamani, A; Visvanathan, C

2014-01-01

Anaerobic co-digestion of high solids containing distillers grains and swine manure (total solids, 27 +/- 2% and 18 +/- 2%, respectively) was evaluated in this study to assess the effect of C/N ratio and organic loading rate (OLR). Feed mixture was balanced to achieve a C/N ratio of 30/1 by mixing distillers grains and swine manure. Pilot-scale co-digestion of distillers grains and swine manure was carried out under thermophilic conditions in the continuous mode for seven different OLRs from R1 to R7 (3.5, 5, 6, 8, 10, 12 and 14 kg VS/m3 day) under high solid anaerobic digestion. The methane yield and volatile solid (VS) removal were consistent; ranging from 0.33 to 0.34 m3CH4/kg VS day and 50-53%, respectively, until OLR 8 kg VS/m3 day. After which methane yield and VS removal significantly decreased to 0.26 m3 CH4/kg VS day and 42%, respectively, when OLR was increased to 14 kg VS/m3 day. However, during operation, at OLR of 10 kg VS/m3 day, the methane yield and VS removal increased after the 19th day to 0.33 m3 CH4/kg VS day and 46%, respectively, indicating that a longer acclimatization period is required by methanogens at a higher loading rate.

SRB attrition rate study of the aft skirt due to water impact cavity collapse loading

NASA Technical Reports Server (NTRS)

Crockett, C. D.

1976-01-01

A methodology was presented so that realistic attrition prediction could aid in selecting an optimum design option for minimizing the effects of updated loads on the Space Shuttle Solid Rocket Booster (SRB) aft skirt. The updated loads resulted in water impact attrition rates greater than 10 percent for the aft skirt structure. Adding weight to reinforce the aft skirt was undesirable. The refined method treats the occurrences of the load distribution probabilistically, radially and longitudinally, with respect to the critical structural response.

Elucidating the impacts of initial supersaturation and seed crystal loading on struvite precipitation kinetics, fines production, and crystal growth.

PubMed

Agrawal, Shantanu; Guest, Jeremy S; Cusick, Roland D

2018-04-01

To reduce intra-plant nutrient cycling, and recover phosphorus (P) fertilizers from nutrient-rich sidestreams, wastewater utilities increasingly elect to employ struvite precipitation processes without a clear understanding of the inherent tradeoffs associated with specific design and operating decisions. Specifically, the impact of reactor conditions on struvite crystallization rate, and distribution between formation of fines particles and secondary growth onto large diameter seed crystals represent critical knowledge gaps limiting the predictive capabilities of existing process models. In this work, the relative impacts of initial supersaturation (S i ), and seed loading, on P removal kinetics, and struvite solids distribution were investigated. In experiments conducted at different levels of initial supersaturation (1.7-2.4) and seed loading (0-25 g L -1 ), struvite fines represented the majority of phosphate solids formed in 10 of 12 conditions. While total P removal was dependent on S i , and primarily attributed to formation of fines, the concentration of struvite seed granules had a significant impact on the rate of P removal. Struvite seed granules increased the rate of precipitation by reducing induction time of primary nucleation of struvite fines. Secondary crystal growth represented the majority of struvite solids formed at high seed loading and low S i , but presented the tradeoff of low total removal and low rate of removal. To convey the significance of these findings on process modeling, we show how a prominent kinetic model with a first-order dependency on solid struvite concentration over-predicts P removal rate when total mass is dominated by large diameter seeds (0.9 mm). This works reveals the critical role of struvite fines in P removal, and highlights the need to account for their production and kinetic importance in struvite process design and operation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Temperature variations at nano-scale level in phase transformed nanocrystalline NiTi shape memory alloys adjacent to graphene layers.

PubMed

Amini, Abbas; Cheng, Chun; Naebe, Minoo; Church, Jeffrey S; Hameed, Nishar; Asgari, Alireza; Will, Frank

2013-07-21

The detection and control of the temperature variation at the nano-scale level of thermo-mechanical materials during a compression process have been challenging issues. In this paper, an empirical method is proposed to predict the temperature at the nano-scale level during the solid-state phase transition phenomenon in NiTi shape memory alloys. Isothermal data was used as a reference to determine the temperature change at different loading rates. The temperature of the phase transformed zone underneath the tip increased by ∼3 to 40 °C as the loading rate increased. The temperature approached a constant with further increase in indentation depth. A few layers of graphene were used to enhance the cooling process at different loading rates. Due to the presence of graphene layers the temperature beneath the tip decreased by a further ∼3 to 10 °C depending on the loading rate. Compared with highly polished NiTi, deeper indentation depths were also observed during the solid-state phase transition, especially at the rate dependent zones. Larger superelastic deformations confirmed that the latent heat transfer through the deposited graphene layers allowed a larger phase transition volume and, therefore, more stress relaxation and penetration depth.

Investigating the Dissolution Performance of Amorphous Solid Dispersions Using Magnetic Resonance Imaging and Proton NMR.

PubMed

Tres, Francesco; Coombes, Steven R; Phillips, Andrew R; Hughes, Leslie P; Wren, Stephen A C; Aylott, Jonathan W; Burley, Jonathan C

2015-09-10

We have investigated the dissolution performance of amorphous solid dispersions of poorly water-soluble bicalutamide in a Kollidon VA64 polymeric matrix as a function of the drug loading (5% vs. 30% bicalutamide). A combined suite of state-of-the-art analytical techniques were employed to obtain a clear picture of the drug release, including an integrated magnetic resonance imaging UV-Vis flow cell system and 1H-NMR. Off-line 1H-NMR was used for the first time to simultaneously measure the dissolution profiles and rates of both the drug and the polymer from a solid dispersion. MRI and 1H-NMR data showed that the 5% drug loading compact erodes linearly, and that bicalutamide and Kollidon VA64 are released at approximately the same rate from the molecular dispersion. For the 30% extrudate, data indicated a slower water ingress into the compact which corresponds to a slower dissolution rate of both bicalutamide and Kollidon VA64.

Modelling studies for photocatalytic degradation of organic dyes using TiO2 nanofibers.

PubMed

Singh, Narendra; Rana, Mohit Singh; Gupta, Raju Kumar

2017-09-05

In this work, modelling of the photocatalytic degradation of para-nitrophenol (PNP) using synthesized electrospun TiO 2 nanofibers under UV light illumination is reported. A dynamic model was developed in order to understand the behaviour of operating parameters, i.e. light intensity and catalyst loading on the photocatalytic activity. This model was simulated and analysed for both TiO 2 solid nanofibers and TiO 2 hollow nanofibers, applied as photocatalysts in the Langmuir-Hinshelwood kinetic framework. The entire photocatalytic degradation rate follows pseudo-first-order kinetics. The simulated results obtained from the developed model are in good agreement with the experimental results. At a catalyst loading of 1.0 mg mL -1 , better respective degradation rates were achieved at UV light irradiance of 4 mW cm -2 , for both the TiO 2 solid and hollow nanofibers. However, it was also observed that TiO 2 hollow nanofibers have a higher adsorption rate than that of TiO 2 solid nanofibers resulting in a higher photocatalytic degradation rate of PNP.

Anaerobic slurry co-digestion of poultry manure and straw: effect of organic loading and temperature

PubMed Central

2013-01-01

In order to obtain basic design criteria for anaerobic digestion of a mixture of poultry manure and wheat straw, the effects of different temperatures and organic loading rates on the biogas yield and methane contents were evaluated. Since poultry manure is a poor substrate, in term of the availability of the nutrients, external supplementation of carbon has to be regularly performed, in order to achieve a stable and efficient process. The complete-mix, pilot-scale digester with working volume of 70 L was used. The digestion operated at 25°C, 30°C and 35°C with organic loading rates of 1.0, 2.0, 2.5, 3.0, 3.5 and 4.0 kg Volatile solid/m3d and a HRT of 15 days. At a temperature of 35°C, the methane yield was increased by 43% compared to 25°C. Anaerobic co-digestion appeared feasible with a loading rate of 3.0 kg VS/m3d at 35°C. At this state, the specific methane yield was calculated about 0.12 m3/kg VS with a methane content of 53–70.2% in the biogas. The volatile solid (VS) removal was 72%. As a result of volatile fatty acid accumulation and decrease in pH, when the loading rate was less than 1 or greater than 4 kg VS/m3d, the process was inhibited or overloaded, respectively. Both the lower and higher loading rates resulted in a decline in the methane yield. PMID:24502409

Evaluation of the Multi-Chambered Treatment Train, a retrofit water-quality management device

USGS Publications Warehouse

Corsi, Steven R.; Greb, Steven R.; Bannerman, Roger T.; Pitt, Robert E.

1999-01-01

This paper presents the results of an evaluation of the benefits and efficiencies of a device called the Multi-Chambered Treatment Train (MCTT), which was installed below the pavement surface at a municipal maintenance garage and parking facility in Milwaukee, Wisconsin. Flow-weighted water samples were collected at the inlet and outlet of the device during 15 storms, and the efficiency of the device was based on reductions in the loads of 68 chemical constituents and organic compounds. High reduction efficiencies were achieved for all particulate-associated constituents, including total suspended solids (98 percent), total phosphorus (88 percent), and total recoverable zinc (91 percent). Reduction rates for dissolved fractions of the constituents were substantial, but somewhat lower (dissolved solids, 13 percent; dissolved phosphorus, 78 percent; dissolved zinc, 68 percent). The total dissolved solids load, which originated from road salt storage, was more than four times the total suspended solids load. No appreciable difference was detected between particle-size distributions in inflow and outflow samples.

Solid state remote power controllers for 120 VDC power systems

NASA Technical Reports Server (NTRS)

Sundberg, G. R.; Baker, D. E.

1975-01-01

Solid state remote power controllers can be applied to any dc power system up to 120 Vdc and distribute power up to 3.6 kW per hour. Devices have demonstrated total electrical efficiencies of 98.5 percent to 99.0 percent at rated load currents.

Hansen solubility parameters (HSP) for prescreening formulation of solid lipid nanoparticles (SLN): in vitro testing of curcumin-loaded SLN in MCF-7 and BT-474 cell lines.

PubMed

Doktorovova, Slavomira; Souto, Eliana B; Silva, Amélia M

2018-01-01

Curcumin, a phenolic compound from turmeric rhizome (Curcuma longa), has many interesting pharmacological effects, but shows very low aqueous solubility. Consequently, several drug delivery systems based on polymeric and lipid raw materials have been proposed to increase its bioavailability. Solid lipid nanoparticles (SLN), consisting of solid lipid matrix and a surfactant layer can load poorly water-soluble drugs, such as curcumin, deliver them at defined rates and enhance their intracellular uptake. In the present work, we demonstrate that, despite the drug's affinity to lipids frequently used in SLN production, the curcumin amount loaded in most SLN formulations may be too low to exhibit anticancer properties. The predictive curcumin solubility in solid lipids has been thoroughly analyzed by Hansen solubility parameters, in parallel with the lipid-screening solubility tests for a range of selected lipids. We identified the most suitable lipid materials for curcumin-loaded SLN, producing physicochemically stable particles with high encapsulation efficiency (>90%). Loading capacity of curcumin in SLN allowed preventing the cellular damage caused by cationic SLN on MCF-7 and BT-474 cells but was not sufficient to exhibit drug's anticancer properties. But curcumin-loaded SLN exhibited antioxidant properties, substantiating the conclusions that curcumin's effect in cancer cells is highly dose dependent.

Effect of particle momentum transfer on an oblique-shock-wave/laminar-boundary-layer interaction

NASA Astrophysics Data System (ADS)

Teh, E.-J.; Johansen, C. T.

2016-11-01

Numerical simulations of solid particles seeded into a supersonic flow containing an oblique shock wave reflection were performed. The momentum transfer mechanism between solid and gas phases in the shock-wave/boundary-layer interaction was studied by varying the particle size and mass loading. It was discovered that solid particles were capable of significant modulation of the flow field, including suppression of flow separation. The particle size controlled the rate of momentum transfer while the particle mass loading controlled the magnitude of momentum transfer. The seeding of micro- and nano-sized particles upstream of a supersonic/hypersonic air-breathing propulsion system is proposed as a flow control concept.

Effects of potential surface coal mining on dissolved solids in Otter Creek and in the Otter Creek alluvial aquifer, southeastern Montana

USGS Publications Warehouse

Cannon, M.R.

1985-01-01

Otter Creek drains an area of 709 square miles in the coal-rich Powder River structural basin of southeastern Montana. The Knobloch coal beds in the Tongue River Member of the Paleocene Fort Union Formation is a shallow aquifer and a target for future surface mining in the downstream part of the Otter Creek basin. A mass-balance model was used to estimate the effects of potential mining on the dissolved solids concentration in Otter Creek and in the alluvial aquifer in the Otter Creek valley. With extensive mining of the Knobloch coal beds, the annual load of dissolved solids to Otter Creek at Ashland at median streamflow could increase by 2,873 tons, or a 32-percent increase compared to the annual pre-mining load. Increased monthly loads of Otter Creek, at the median streamflow, could range from 15 percent in February to 208 percent in August. The post-mining dissolved solids load to the subirrigated part of the alluvial valley could increase by 71 percent. The median dissolved solids concentration in the subirrigated part of the valley could be 4,430 milligrams per liter, compared to the pre-mining median concentration of 2,590 milligrams per liter. Post-mining loads from the potentially mined landscape were calculated using saturated-paste-extract data from 506 overburdened samples collected from 26 wells and test holes. Post-mining loads to the Otter Creek valley likely would continue at increased rates for hundreds of years after mining. If the actual area of Knobloch coal disturbed by mining were less than that used in the model, post-mining loads to the Otter Creek valley would be proportionally smaller. (USGS)

Power controller 28Vdc load switching (N. O. SPST). Final report, 31 August 1977-21 January 1980

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

McMackin, J.B.

1980-01-21

A solid state power controller has been designed in four ratings to switch 28Vdc power to selected loads upon remote command. The four ratings trip out at currents of 10, 5, 2 and 1/2 amps. The design allows for wide variations in load and supply voltage and will not trip out on short load transients of up to 1000% of rated load current. In case of failure of the controller circuitry, an internal fuse protects the load from excessive current. The control current which operates the controller also provides a sensing function so that the state of the controller canmore » be determined remotely. The controllers are designed to operate over a case temperature range of -54 C to 120 C. A quantity of 100 units have been fabricated, tested, and supplied to the Navy.« less

Dissolved-solids loads discharged from irrigated areas near Manila, Utah, May 2007-October 2012, and relation of loads to selected variables

USGS Publications Warehouse

Thiros, Susan A.; Gerner, Steven J.

2015-01-01

Irrigation improvements began to be implemented in 2007 to reduce dissolved-solids loads discharged from the MWSP area. The theoretical annual net dissolved-solids load where the cumulative NRCS calculated dissolved-solids load reduction is added to the net MWSP dissolved-solids load is what would be expected if there was no irrigation improvement in the area associated with the MWSP. The theoretical data points lie very near the baseline representing the pre-MWSP dissolved-solids load to canal streamflow relation. The proximity of the theoretical data points to the baseline shows that the NRCS calculations of reduction in dissolved-solids load are generally supported by the data collected during this study.

Influence of sludge properties and hydraulic loading on the performance of secondary settling tanks--full-scale operational results.

PubMed

Vestner, R J; Günthert, F Wolfgang

2004-01-01

Full-scale investigations at a WWTP with a two-stage secondary settling tank process revealed relationships between significant operating parameters and performance in terms of effluent suspended solids concentration. Besides common parameters (e.g. surface overflow rate and sludge volume loading rate) feed SS concentration and flocculation time must be considered. Concentration of the return activated sludge may help to estimate the performance of existing secondary settling tanks.

Microscopic modeling of confined crystal growth and dissolution.

PubMed

Høgberget, Jørgen; Røyne, Anja; Dysthe, Dag K; Jettestuen, Espen

2016-08-01

We extend the (1+1)-dimensional fluid solid-on-solid (SOS) model to include a confining flat surface opposite to the SOS surface subject to a constant load. This load is balanced by a repulsive surface-surface interaction given by an ansatz which agrees with known analytical solutions in the limit of two separated flat surfaces. Mechanical equilibrium is imposed at all times by repositioning the confining surface. By the use of kinetic Monte Carlo (KMC) we calculate how the equilibrium concentration (deposition rate) depends on the applied load, and find it to reproduce analytical thermodynamics independent of the parameters of the interaction ansatz. We also study the dependency between the surface roughness and the saturation level as we vary the surface tension, and expand on previous analyses of the asymmetry between growth and dissolution by parametrizing the linear growth rate constant for growth and dissolution separately. We find the presence of a confining surface to affect the speed of growth and dissolution equally.

Microscopic modeling of confined crystal growth and dissolution

NASA Astrophysics Data System (ADS)

Høgberget, Jørgen; Røyne, Anja; Dysthe, Dag K.; Jettestuen, Espen

2016-08-01

We extend the (1+1)-dimensional fluid solid-on-solid (SOS) model to include a confining flat surface opposite to the SOS surface subject to a constant load. This load is balanced by a repulsive surface-surface interaction given by an ansatz which agrees with known analytical solutions in the limit of two separated flat surfaces. Mechanical equilibrium is imposed at all times by repositioning the confining surface. By the use of kinetic Monte Carlo (KMC) we calculate how the equilibrium concentration (deposition rate) depends on the applied load, and find it to reproduce analytical thermodynamics independent of the parameters of the interaction ansatz. We also study the dependency between the surface roughness and the saturation level as we vary the surface tension, and expand on previous analyses of the asymmetry between growth and dissolution by parametrizing the linear growth rate constant for growth and dissolution separately. We find the presence of a confining surface to affect the speed of growth and dissolution equally.

Porous Silica-Supported Solid Lipid Particles for Enhanced Solubilization of Poorly Soluble Drugs.

PubMed

Yasmin, Rokhsana; Rao, Shasha; Bremmell, Kristen E; Prestidge, Clive A

2016-07-01

Low dissolution of drugs in the intestinal fluid can limit their effectiveness in oral therapies. Here, a novel porous silica-supported solid lipid system was developed to optimize the oral delivery of drugs with limited aqueous solubility. Using lovastatin (LOV) as the model poorly water-soluble drug, two porous silica-supported solid lipid systems (SSL-A and SSL-S) were fabricated from solid lipid (glyceryl monostearate, GMS) and nanoporous silica particles Aerosil 380 (silica-A) and Syloid 244FP (silica-S) via immersion/solvent evaporation. SSL particles demonstrated significantly higher rate and extent of lipolysis in comparison with the pure solid lipid, depending on the lipid loading levels and the morphology. The highest lipid digestion was observed when silica-S was loaded with 34% (w/w) solid lipid, and differential scanning calorimeter (DSC) analysis confirmed the encapsulation of up to 2% (w/w) non-crystalline LOV in this optimal SSL-S formulation. Drug dissolution under non-digesting intestinal conditions revealed a three- to sixfold increase in dissolution efficiencies when compared to the unformulated drug and a LOV-lipid suspension. Furthermore, the SSL-S provided superior drug solubilization under simulated intestinal digesting condition in comparison with the drug-lipid suspension and drug-loaded silica. Therefore, solid lipid and nanoporous silica provides a synergistic effect on optimizing the solubilization of poorly water-soluble compound and the solid lipid-based porous carrier system provides a promising delivery approach to overcome the oral delivery challenges of poorly water-soluble drugs.

Solid lipid nanoparticles as an efficient drug delivery system of olmesartan medoxomil for the treatment of hypertension.

PubMed

Pandya, Nilima T; Jani, Parva; Vanza, Jigar; Tandel, Hemal

2018-05-01

The aim of the current investigation was to develop solid lipid nanoparticles of olmesartan medoxomil using hot homogenization method to improve its oral bioavailability. Central composite design was applied to optimize the formulation variables; lipid X1 (Glyceryl monostearate) and surfactant X2 (Poloxamer: Tween 80). The particle sizes were in the nanometer range and spherical shaped for all prepared solid lipid nanoparticles formulations and the zeta potential absolute values were high, predicting good long-term stability. In vitro study of olmesartan loaded solid lipid nanoparticle exhibited controlled release profile for at least 24 h. The rate and extent of drug diffusion was studied using dialysis sac, rat's stomach and intestine tissues; study demonstrated that drug release from the solid lipid nanoparticles was significantly higher than drug suspension. In vivo pharmacokinetic study of olmesartan loaded solid lipid nanoparticles revealed higher Cmax of 1610 ng/mL, higher AUC of 15492.50 ng/mL and increased relative bioavailability by almost 2.3 folds compared to marketed formulation. These results clearly indicate that olmesartan loaded solid lipid nanoparticles are shown to have enhanced bioavailability and effective therapeutic result and thus would be an excellent way to treat hypertension. Hence, these solid lipid nanoparticles could represent as a great potential for a possible alternative to conventional oral formulation in the treatment of hypertension. Copyright © 2018 Elsevier B.V. All rights reserved.

Improvement in hardness of soda-lime-silica glass

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

Chakraborty, Riya; De, Moumita; Roy, Sudakshina

2012-06-05

Hardness is a key design parameter for structural application of brittle solids like glass. Here we report for the first time the significant improvement of about 10% in Vicker's hardness of a soda-lime-silica glass with loading rate in the range of 0.1-10 N.s{sup -1}. Corroborative dark field optical and scanning electron microscopy provided clue to this improvement through evidence of variations in spatial density of shear deformation band formation as a function of loading rate.

Two-phase non-Newtonian hydrodynamic modeling of slurries

NASA Astrophysics Data System (ADS)

Wang, C. S.; Lyczkowski, R. W.; Berry, G. F.

The two-phase hydrodynamic theory of fluid/solid flow has been extended to incorporate the constitutive relationship for power-law non-Newtonian behavior. A model has been developed to predict the spatial and temporal variations in solids and liquid velocities and concentration of non-Newtonian slurries under high shear rates in diesel engine injection systems. Comparisons between the present non-Newtonian two-phase theory and the conventional theory have also been made. Selected results for diesel injection nozzle applications are presented. The results from this model can be used to calculate directly the erosion rates at the nozzle boundaries and the solids loading at the nozzle exit.

Effects of total solids content on waste activated sludge thermophilic anaerobic digestion and its sludge dewaterability.

PubMed

Wang, Tianfeng; Chen, Jie; Shen, Honglang; An, Dong

2016-10-01

The role of total solids content on sludge thermophilic anaerobic digestion was investigated in batch reactors. A range of total solids content from 2% to 10% was evaluated with two replicates. The lowest inhibitory concentration for free ammonia and total ammonia of sludge thermophilic anaerobic digestion was 110.9-171.4mg/L and 1313.1-1806.7mg/L, respectively. The volumetric biogas production rate increased with increasing of total solids content, but the corresponding biogas yield per gram volatile solid decreased. The result of normalized capillary suction time indicated that the dewaterability of digested sludge at high total solids content was poor, while solid content of sediment obtained by centrifuging sludge at 2000g for 10min increased with increasing of total solids content of sludge. The results suggest that thickened sludge mixed with dewatered sludge at an appropriate ratio could get high organic loading rate, high biogas yield and adequate dewatering effort. Copyright © 2016 Elsevier Ltd. All rights reserved.

Corrosion in MDEA sour gas treating plants: Correlation between laboratory testing and field experience

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

Bich, N.N.; Vacha, F.; Schubert, R.

1996-08-01

Corrosion in MDEA sour gas treating systems operating in severely loaded conditions is investigated using both laboratory data and actual gas plant experience. Effects of acid gas loading, flow turbulence, solution quality, temperature, etc. on corrosion are being studied. Preliminary results indicated severe corrosion of several mm/y would occur if acid gas loading, circulation rate and level of suspended solids are all high. A mitigation strategy based on operating envelopes is formulated.

Effect of aeration rate and waste load on evolution of volatile fatty acids and waste stabilization during thermophilic aerobic digestion of a model high strength agricultural waste.

PubMed

Ugwuanyi, J Obeta; Harvey, L M; McNeil, B

2005-04-01

Thermophilic aerobic digestion (TAD) is a relatively new, dynamic and versatile low technology for the economic processing of high strength waste slurries. Waste so treated may be safely disposed of or reused. In this work a model high strength agricultural waste, potato peel, was subjected to TAD to study the effects of oxygen supply at 0.1, 0.25, 0.5 and 1.0 vvm (volume air per volume slurry per minute) under batch conditions at 55 degrees C for 156 h on the process. Process pH was controlled at 7.0 or left unregulated. Effects of waste load, as soluble chemical oxygen demand (COD), on TAD were studied at 4.0, 8.0, 12.0 and 16.0 gl(-1) (soluble COD) at pH 7.0, 0.5 vvm and 55 degrees C. Efficiency of treatment, as degradation of total solids, total suspended solids and soluble solid, as well as soluble COD significantly increased with aeration rate, while acetate production increased as the aeration rate decreased or waste load increased, signifying deterioration in treatment. Negligible acetate, and no other acids were produced at 1.0 vvm. Production of propionate and other acids increased after acetate concentration had started to decrease and, during unregulated reactions coincided with the drop in the pH of the slurry. Acetate production was more closely associated with periods of oxygen limitation than were other acids. Reduction in oxygen availability led to deterioration in treatment efficiency as did increase in waste load. These variables may be manipulated to control treated waste quality.

Enzymatic Hydrolysis and Simultaneous Saccharification and Fermentation of Soybean Processing Intermediates for the Production of Ethanol and Concentration of Protein and Lipids

PubMed Central

Long, Craig C.; Gibbons, William

2012-01-01

Carbohydrates in soybeans are generally undesirable due to their low digestibility and because they “dilute” more valuable components (proteins, lipids). To remove these carbohydrates and raise the titer of more valuable components, ethanol production was investigated. Commercial enzymes (Novozyme cellulase, β-glucosidase, and pectinase) were added to ground soybeans (SB), soybean meal (SBM), soybean hulls (SH), and soybean white flakes (WF) at a 10% solids loading rate to quantify hydrolyzed glucan. Saccharification resulted in glucan reductions of 28%, 45%, 76%, and 80% (SBM, SB, SH, WF, resp.). Simultaneous saccharification and fermentation (SSF) trials were conducted at 5%, 10%, 15%, and 20% solids loading with Saccharomyces cerevisiae NRRL Y-2034 and Scheffersomyces stipitis NRRL Y-7124, with protein, fiber, and lipids analyzed at SSF 10% solids and saccharification trials. S. cerevisiae and S. stipitis produced ~3–12.5 g/L ethanol and ~2.5–8.6 g/L ethanol, respectively, on SB, SBM, and WF over all solid loading rates. SH resulted in higher ethanol titers for both S. cerevisiae (~9–23 g/L) and S. stipitis (~9.5–14.5 g/L). Protein concentrations decreased by 2.5–10% for the SB, SBM, and WF, but increased by 53%–55% in SH. Oil concentrations increased by ~50% for SB; by ~500%–1300% for the others. PMID:23762751

Nutrient variations from swine manure to agricultural land

PubMed Central

You, Byung-Gu; Shim, Soomin; Choi, Yoon-Seok

2018-01-01

Objective Swine manure in Korea is separated into solid and liquid phases which are composted separately and then applied on land. The nutrient accumulation in soil has been a big issue in Korea but the basic investigation about nutrient input on arable land has not been achieved in detail. Within the nutrient production from livestock at the national level, most values are calculated by multiplication of the number of animals with the excreta unit per animal. However, the actual amount of nutrients from swine manure may be totally different with the nutrients applied to soil since livestock breeding systems are not the same with each country. Methods This study investigated 15 farms producing solid compost and 14 farms producing liquid compost. Composting for solid phase used the Turning+Aeration (TA) or Turning (T) only methods, while liquid phase aeration composting was achieved by continuous (CA), intermittent (IA), or no aeration (NA). Three scenarios were constructed for investigating solid compost: i) farm investigation, ii) reference study, and iii) theoretical P changes (ΔP = 0), whereas an experiment for water evaporation was conducted for analyzing liquid compost. Results In farm investigation, weight loss rates of 62% and 63% were obtained for TA and T, respectively, while evaporation rates for liquid compost were 8.75, 7.27, and 5.14 L/m2·d for CA, IA, and NA, respectively. Farm investigation provided with the combined nutrient load (solid+liquid) of VS, N, and P of 117.6, 7.2, and 2.7 kg/head·yr. Nutrient load calculated from farm investigation is about two times higher than the calculated with reference documents. Conclusion The nutrient loading coefficients from one swine (solid+liquid) were (volatile solids, 0.79; nitrogen, 0.53; phosphorus, 0.71) with nutrient loss of 21%, 47%, and 29%, respectively. The nutrient count from livestock manure using the excretion unit has probably been overestimated without consideration of the nutrient loss. PMID:29268574

Estimation of nonpoint-source loads of total nitrogen, total phosphorous, and total suspended solids in the Black, Belle, and Pine River basins, Michigan, by use of the PLOAD model

USGS Publications Warehouse

Syed, Atiq U.; Jodoin, Richard S.

2006-01-01

The Lake St. Clair Regional Monitoring Project partners planned a 3-year assessment study of the surface water in the Lake St. Clair drainage basins in Michigan. This study included water-quality monitoring and analysis, collection of discrete (grab) and automatic water-quality samples, monitoring of bacteria, and the creation of a database to store all relevant data collected from past and future field-data-collection programs. In cooperation with the Lake St. Clair Monitoring Project, the U.S. Geological Survey assessed nonpoint-source loads of nutrients and total suspended solids in the Black, Belle, and Pine River basins. The principal tool for the assessment study was the USEPA’s PLOAD model, a simplified GIS-based numerical program that generates gross estimates of pollutant loads. In this study, annual loads were computed for each watershed using the USEPA’s Simple Method, which is based on scientific studies showing a correlation between different land-use types and loading rates. The two land-use data sets used in the study (representing 1992 and 2001) show a maximum of 0.02-percent change in any of the 15 land use categories between the two timeframes. This small change in land use is reflected in the PLOAD results of the study area between the two time periods. PLOAD model results for the 2001 land-use data include total-nitrogen loads from the Black, Belle, and Pine River basins of approximately 495,599 lb/yr, 156,561 lb/yr, and 121,212 lb/yr, respectively; total-phosphorus loads of 80,777 lb/yr, 25,493 lb/yr, and 19,655 lb/yr, respectively; and total-suspended-solids loads of 5,613,282 lb/yr, 1,831,045 lb/yr, and 1,480,352 lb/yr, respectively. The subbasins in the Black, Belle, and Pine River basin with comparatively high loads are characterized by comparatively high percentages of industrial, commercial, transportation, or residential land use. The results from the PLOAD model provide useful information about the approximate average annual loading rates from the three study basins. In particular, the results identify subbasins with comparatively high loading rates per square mile. This could aid water-resources managers and planners in evaluation of the effectiveness of public expenditures for water-quality improvements, assessment of progress towards achieving established water-quality goals, and planning of preventive actions.

Application of the endochronic theory of viscoplasticity to solid propellants and sandasphalt concrete

NASA Technical Reports Server (NTRS)

Peng, S. T. J.; Valanis, K. C.

1977-01-01

Solid propellants, sand-asphalt concrete and hard plastics showed rate sensitive mechanical behavior which, in addition, indicated that these materials have a permanent memory of the strain (or loading) path by which their present state was attained. A constitutive equation was formulated in general three dimensional tensorial form by means of irreversible thermodynamics. By using a very simple analytical form, it was shown that the mechanical behavior of solid propellants and sand-asphalt concrete can be readily described.

Anaerobic digestion of municipal solid wastes containing variable proportions of waste types.

PubMed

Akunna, J C; Abdullahi, Y A; Stewart, N A

2007-01-01

In many parts of the world there are significant seasonal variations in the production of the main organic wastes, food and green wastes. These waste types display significant differences in their biodegradation rates. This study investigated the options for ensuring process stability during the start up and operation of thermophilic high-solids anaerobic digestion of feedstock composed of varying proportions of food and green wastes. The results show that high seed sludge to feedstock ratio (or low waste loading rate) is necessary for ensuring process pH stability without chemical addition. It was also found that the proportion of green wastes in the feedstock can be used to regulate process pH, particularly when operating at high waste loading rates (or low seed sludge to feedstock ratios). The need for chemical pH correction during start-up and digestion operation decreased with increase in green wastes content of the feedstock. Food wastes were found to be more readily biodegradable leading to higher solids reduction while green wastes brought about pH stability and higher digestate solid content. Combining both waste types in various proportions brought about feedstock with varying buffering capacity and digestion performance. Thus, careful selection of feedstock composition can minimise the need for chemical pH regulation as well as reducing the cost for digestate dewatering for final disposal.

Effect of load ratio on fatigue crack propagation behavior of solid-solution-strengthened Ni-based superalloys at elevated temperature

NASA Astrophysics Data System (ADS)

Ma, Longzhou; Roy, Shawoon K.

2013-04-01

The fatigue crack propagation (FCP) behavior of two solid-solution-strengthened Ni-based superalloys, INCONEL 617 and HAYNES 230, were studied simultaneously in laboratory air using a constant stress intensity factor (K)-controlled mode with different load ratios (R-ratio) at 700 °C. The FCP tests were performed in both cycle and time-dependent FCP domains to examine the effect of R-ratio on the FCP rate, da/dn. For cycle-dependent FCP test, a 1-s sinusoidal fatigue was applied for a compact tension (CT) specimen of INCONEL 617 and HAYNES 230 to measure their FCP rates. For time-dependent FCP test, a 3-s sinusoidal fatigue with a hold time of 300 s at maximum load was applied. Both cycle/time-dependent FCP behaviors were characterized and analyzed. The results showed that increasing R-ratio would introduce the fatigue incubation and decrease the FCP rates at cycle-dependent FCP tests. On the contrary, fatigue incubation was not observed at time-dependent FCP tests for both INCONEL 617 and HAYNES 230 at each tested R-ratio, suggesting that association of maximum load (Kmax) with crack tip open displacement (CTOD) and environmental factor governed the FCP process. Also, for time-dependent FCP, HAYNES 230 showed lower FCP rates than INCONEL 617 regardless of R-ratio. However, for cycle-dependent FCP, HAYNES 230 showed the lower FCP rates only at high R-ratios. Fracture surface of specimens were examined using SEM to investigate the cracking mechanism under cycle/time-dependent FCP condition with various R-ratios.

Effects of particulate radiation on premixed gas flames

NASA Technical Reports Server (NTRS)

Abbud-Madrid, Angel; Ronney, Paul D.

1993-01-01

Observations of the effect of the addition of fine solid particles to weakly combustible methane-air mixtures are reported. Burning rates, pressure rise, and thermal characteristics are found to exhibit nonmonotonic trends with increasing particle loading. These results are interpreted in terms of the effects of augmentation of radiant loss at small particle loadings and re-absorption of emitted radiation at larger loadings. It is suggested that in sufficiently large systems, flammability limits might not exist because of this reabsorption effect.

Is earthquake rate in south Iceland modified by seasonal loading?

NASA Astrophysics Data System (ADS)

Jonsson, S.; Aoki, Y.; Drouin, V.

2017-12-01

Several temporarily varying processes have the potential of modifying the rate of earthquakes in the south Iceland seismic zone, one of the two most active seismic zones in Iceland. These include solid earth tides, seasonal meteorological effects and influence from passing weather systems, and variations in snow and glacier loads. In this study we investigate the influence these processes may have on crustal stresses and stressing rates in the seismic zone and assess whether they appear to be influencing the earthquake rate. While historical earthquakes in the south Iceland have preferentially occurred in early summer, this tendency is less clear for small earthquakes. The local earthquake catalogue (going back to 1991, magnitude of completeness < 1.0) has indeed more earthquakes in summer than in winter. However, this pattern is strongly influenced by aftershock sequences of the largest M6+ earthquakes, which occurred in June 2000 and May 2008. Standard Reasenberg earthquake declustering or more involved model independent stochastic declustering algorithms are not capable of fully eliminating the aftershocks from the catalogue. We therefore inspected the catalogue for the time period before 2000 and it shows limited seasonal tendency in earthquake occurrence. Our preliminary results show no clear correlation between earthquake rates and short-term stressing variations induced from solid earth tides or passing storms. Seasonal meteorological effects also appear to be too small to influence the earthquake activity. Snow and glacier load variations induce significant vertical motions in the area with peak loading occurring in Spring (April-May) and maximum unloading in Fall (Sept.-Oct.). Early summer occurrence of historical earthquakes therefore correlates with early unloading rather than with the peak unloading or unloading rate, which appears to indicate limited influence of this seasonal process on the earthquake activity.

Effects of friction layer characteristics on the tribological properties of Ni3Al solid-lubricating composites at different load conditions

NASA Astrophysics Data System (ADS)

Lu, Guanchen; Shi, Xiaoliang; Huang, Yuchun; Liu, Xiyao; Yang, Meijun

2018-05-01

This paper investigates the effects of friction layer characteristics of Ni3Al matrix self-lubricating composites (NMCs) on the tribological properties sliding against ceramic ball Si3N4 at dry friction process at the different load conditions. The characteristics of friction layer are performed in terms of hardness of wear scars, thickness and elemental distributions of friction layer. The results show that the microhardness of wear scars of NMCs increases with the increase of the sliding time and applied load, which results in friction coefficient reduced and wear rate decreased, indicating that the tribological performance of NMCs is obviously affected by microhardness of wear scar. However, under excessive applied load, the performance of friction layer of NMCs is deteriorated for the spalling of wear debris and deformation of contact surface. Therefore, selecting appropriate load conditions during the sliding contact, at the transition to the optimal properties of friction layer maybe occur. NMCs exhibits excellent tribological properties at 15N, which leads to the lowest friction coefficient (0.386) and wear rate (2.48 × 10‑5 mm3 N‑1 m‑1), as well as the smoothest surface of wear track compared with the other load conditions. Meanwhile, the elemental distributions analysis of cross-section of friction layer of NMCs shows that the frictional structures can be divided into three main layers. The thickness of the friction-affected layer varies with the changing of applied load. These results could provide a reference for preparing the solid-lubrication materials with better tribological properties.

Dissolved-Solids Load in Henrys Fork Upstream from the Confluence with Antelope Wash, Wyoming, Water Years 1970-2009

USGS Publications Warehouse

Foster, Katharine; Kenney, Terry A.

2010-01-01

Annual dissolved-solids load at the mouth of Henrys Fork was estimated by using data from U.S. Geological Survey streamflow-gaging station 09229500, Henrys Fork near Manila, Utah. The annual dissolved-solids load for water years 1970-2009 ranged from 18,300 tons in 1977 to 123,300 tons in 1983. Annual streamflows for this period ranged from 14,100 acre-feet in 1977 to 197,500 acre-feet in 1983. The 25-percent trimmed mean dissolved-solids load for water years 1970-2009 was 44,300 tons per year at Henrys Fork near Manila, Utah. Previous simulations using a SPAtially Referenced Regression On Watershed attributes (SPARROW) model for dissolved solids specific to water year 1991 conditions in the Upper Colorado River Basin predicted an annual dissolved-solids load of 25,000 tons for the Henrys Fork Basin upstream from Antelope Wash. On the basis of computed dissolved-solids load data from Henrys Fork near Manila, Utah, together with estimated annual dissolved-solids load from Antelope Wash and Peoples Canal, this prediction was adjusted to 37,200 tons. As determined by simulations with the Upper Colorado River Basin SPARROW model, approximately 56 percent (14,000 tons per year) of the dissolved-solids load at Henrys Fork upstream from Antelope Wash is associated with the 21,500 acres of irrigated agricultural lands in the upper Henrys Fork Basin.

Dissolved-solids transport in surface water of the Muddy Creek Basin, Utah

USGS Publications Warehouse

Gerner, Steven J.

2008-01-01

Muddy Creek is located in the southeastern part of central Utah and is a tributary of the Dirty Devil River, which, in turn, is a tributary of the Colorado River. Dissolved solids transported from the Muddy Creek Basin may be stored in the lower Dirty Devil River Basin, but are eventually discharged to the Colorado River and impact downstream water users. This study used selected dissolved-solids measurements made by various local, State, and Federal agencies from the 1970s through 2006, and additional dissolved-solids data that were collected by the U.S. Geological Survey during April 2004 through November 2006, to compute dissolved-solids loads, determine the distribution of dissolved-solids concentrations, and identify trends in dissolved-solids concentration in surface water of the Muddy Creek Basin. The dissolved-solids concentration values measured in water samples collected from Muddy Creek during April 2004 through October 2006 ranged from 385 milligrams per liter (mg/L) to 5,950 mg/L. The highest dissolved-solids concentration values measured in the study area were in water samples collected at sites in South Salt Wash (27,000 mg/L) and Salt Wash (4,940 to 6,780 mg/L). The mean annual dissolved-solids load in Muddy Creek for the periods October 1976 to September 1980 and October 2005 to September 2006 was smallest at a site near the headwaters (9,670 tons per year [tons/yr]) and largest at a site at the mouth (68,700 tons/yr). For this period, the mean annual yield of dissolved solids from the Muddy Creek Basin was 44 tons per square mile. During October 2005 to September 2006, direct runoff transported as much as 45 percent of the annual dissolved-solids load at the mouth of Muddy Creek. A storm that occurred during October 5?7, 2006 resulted in a peak streamflow at the mouth of Muddy Creek of 7,150 cubic feet per second (ft3/s) and the transport of an estimated 35,000 tons of dissolved solids, which is about 51 percent of the average annual dissolved-solids load at the mouth of Muddy Creek. A significant downward trend in dissolved-solids concentrations from 1973 to 2006 was determined for Muddy Creek at a site just downstream of that portion of the basin containing agricultural land. Dissolved-solids concentrations decreased about 2.1 percent per year; however, the rate of change was a decrease of 1.8 percent per year when dissolved-solids concentrations were adjusted for flow.

Effect of freezing conditions on β-Tricalcium Phosphate /Camphene scaffold with micro sized particles fabricated by freeze casting.

PubMed

Singh, Gurdev; Soundarapandian, S

2018-03-01

The long standing need of the implant manufacturing industries is to fabricate multi-matrix, customized porous scaffold as cost-effectively. In recent years, freeze casting has shown greater opportunity in the fabrication of porous scaffolds (tricalcium phosphate, hydroxyapatite, bioglass, alumina, etc.) such as at ease and good control over pore size, porosity, a range of materials and economic feasibility. In particular, tricalcium phosphate (TCP) has proved as it possesses good biocompatible (osteoinduction, osteoconduction, etc.) and biodegradability hence beta-tricalcium phosphate (β-TCP, particle size of 10µm) was used as base material and camphene was used as a freezing vehicle in this study. Both freezing conditions such as constant freezing temperature (CFT) and constant freezing rate (CFR) were used for six different conditional samples (CFT: 30, 35 and 40vol% solid loading; similarly CFR: 30, 35 and 40vol% solid loading) to study and understand the effect of various properties (pore size, porosity and compressive strength) of the freeze-cast porous scaffold. It was observed that the average size of the pore was varying linearly as from lower to higher when the solid loading was varying higher to lower. With the help of scanning electron micrographs (SEM), it was observed that the average size of pore during CFR (9.7/ 6.5/ 4.9µm) was comparatively higher than the process of CFT (6.0/ 4.8/ 2.6µm) with respect to the same solid loading (30/ 35/ 40vol%) conditions. From the Gas pycnometer analysis, it was found that the porosity in both freezing conditions (CFT, CFR) were almost near values such as 32.8% and 28.5%. Further to be observed that with the increase in solid loading, the total porosity value has decreased due to the reduction in the concentration of the freezing vehicle. Hence, the freezing vehicle was found as responsible for the formation of appropriate size and orientation of pores during freeze casting. The compressive strength (CS) testing was clearly indicated that the CS was majorly depending on the size of pore which was depending on solid loading. The CS of CFT-based samples (smaller pore sizes and higher resistance to the propagation of crack) were higher due to the higher solid content (pore size) in compared with CFR-based samples on the similar solid loading conditions. As evidently, it was noted that the CFT-based sample with 40% solid loading has given the compressive strength which has come in the range of cancellous bone. The positive note was that the ratio of Ca/P has come as 1.68 (natural bone) after sintering and that was the required value recommended by the food and drug administration (FDI) for manufacturing of bone implants. Copyright © 2017 Elsevier Ltd. All rights reserved.

An improved heat transfer configuration for a solid-core nuclear thermal rocket engine

NASA Technical Reports Server (NTRS)

Clark, John S.; Walton, James T.; Mcguire, Melissa L.

1992-01-01

Interrupted flow, impingement cooling, and axial power distribution are employed to enhance the heat-transfer configuration of a solid-core nuclear thermal rocket engine. Impingement cooling is introduced to increase the local heat-transfer coefficients between the reactor material and the coolants. Increased fuel loading is used at the inlet end of the reactor to enhance heat-transfer capability where the temperature differences are the greatest. A thermal-hydraulics computer program for an unfueled NERVA reactor core is employed to analyze the proposed configuration with attention given to uniform fuel loading, number of channels through the impingement wafers, fuel-element length, mass-flow rate, and wafer gap. The impingement wafer concept (IWC) is shown to have heat-transfer characteristics that are better than those of the NERVA-derived reactor at 2500 K. The IWC concept is argued to be an effective heat-transfer configuration for solid-core nuclear thermal rocket engines.

Effect of propellant deformation on ignition and combustion processes in solid propellant cracks

NASA Technical Reports Server (NTRS)

Kumar, M.; Kuo, K. K.

1980-01-01

A comprehensive theoretical model was formulated to study the development of convective burning in a solid propellant crack which continually deforms due to burning and pressure loading. In the theoretical model, the effect of interrelated structural deformation and combustion processes was taken into account by considering (1) transient, one dimensional mass, momentum, and energy conservation equations in the gas phase; (2) a transient, one dimensional heat conduction equation in the solid phase; and (3) quasi-static deformation of the two dimensional, linear viscoelastic propellant crack caused by pressure loading. Partial closures may generate substantial local pressure peaks along the crack, implying a strong coupling between chamber pressurization, crack combustion, and propellant deformation, especially when the cracks are narrow and the chamber pressurization rates high. The maximum pressure in the crack cavity is generally higher than that in the chamber. The initial flame-spreading process is not affected by propellant deformation.

Development of a new delivery system consisting in 'drug-in cyclodextrin-in PLGA nanoparticles'.

PubMed

Mura, Paola; Maestrelli, Francesca; Cecchi, Matteo; Bragagni, Marco; Almeida, Antonio

2010-01-01

A combined approach based on drug cyclodextrin (CD) complexation and loading into PLGA nanoparticles (NP) has been developed to improve oxaprozin therapeutic efficiency. This strategy exploits the solubilizing and stabilizing properties of CDs and the prolonged-release and targeting properties of PLGA NPs. Drug-loaded NPs, prepared by double-emulsion, were examined for dimensions, zeta-potential and entrapment efficiency. Solid-state studies demonstrated the absence of drug-polymer interactions and assessed the amorphous state of the drug-CD complex loaded into NPs. Drug release rate from NPs was strongly influenced by the presence and kind of CD used. The percentage released at 24 h varied from 16% (plain drug-loaded NPs) to 50% (drug-betaCD-loaded NPs) up to 100% (drug-methylbetaCD-loaded NPs). This result suggests the possibility of using CD complexation not only to promote, but also to regulate drug release rate from NPs, by selecting the proper type of CD or CD combination.

Interaction of rate- and size-effect using a dislocation density based strain gradient viscoplasticity model

NASA Astrophysics Data System (ADS)

Nguyen, Trung N.; Siegmund, Thomas; Tomar, Vikas; Kruzic, Jamie J.

2017-12-01

Size effects occur in non-uniform plastically deformed metals confined in a volume on the scale of micrometer or sub-micrometer. Such problems have been well studied using strain gradient rate-independent plasticity theories. Yet, plasticity theories describing the time-dependent behavior of metals in the presence of size effects are presently limited, and there is no consensus about how the size effects vary with strain rates or whether there is an interaction between them. This paper introduces a constitutive model which enables the analysis of complex load scenarios, including loading rate sensitivity, creep, relaxation and interactions thereof under the consideration of plastic strain gradient effects. A strain gradient viscoplasticity constitutive model based on the Kocks-Mecking theory of dislocation evolution, namely the strain gradient Kocks-Mecking (SG-KM) model, is established and allows one to capture both rate and size effects, and their interaction. A formulation of the model in the finite element analysis framework is derived. Numerical examples are presented. In a special virtual creep test with the presence of plastic strain gradients, creep rates are found to diminish with the specimen size, and are also found to depend on the loading rate in an initial ramp loading step. Stress relaxation in a solid medium containing cylindrical microvoids is predicted to increase with decreasing void radius and strain rate in a prior ramp loading step.

Anaerobic co-digestion of food waste and dairy manure: effects of food waste particle size and organic loading rate.

PubMed

Agyeman, Fred O; Tao, Wendong

2014-01-15

This study was to comprehensively evaluate the effects of food waste particle size on co-digestion of food waste and dairy manure at organic loading rates increased stepwise from 0.67 to 3 g/L/d of volatile solids (VS). Three anaerobic digesters were fed semi-continuously with equal VS amounts of food waste and dairy manure. Food waste was ground to 2.5 mm (fine), 4 mm (medium), and 8 mm (coarse) for the three digesters, respectively. Methane production rate and specific methane yield were significantly higher in the digester with fine food waste. Digestate dewaterability was improved significantly by reducing food waste particle size. Specific methane yield was highest at the organic loading rate of 2g VS/L/d, being 0.63, 0.56, and 0.47 L CH4/g VS with fine, medium, and coarse food waste, respectively. Methane production rate was highest (1.40-1.53 L CH4/L/d) at the organic loading rate of 3 g VS/L/d. The energy used to grind food waste was minor compared with the heating value of the methane produced. Copyright © 2013 Elsevier Ltd. All rights reserved.

Semi-continuous anaerobic co-digestion of sugar beet byproduct and pig manure: Effect of the organic loading rate (OLR) on process performance.

PubMed

Aboudi, Kaoutar; Álvarez-Gallego, Carlos José; Romero-García, Luis Isidoro

2015-10-01

Anaerobic co-digestion of dried pellet of exhausted sugar beet cossettes (ESBC-DP) with pig manure (PM) was investigated in a semi-continuous stirred tank reactor (SSTR) under mesophilic conditions. Seven hydraulic retention times (HRT) from 20 to 5 days were tested with the aim to evaluate the methane productivities and volatile solids (VS) removal. The corresponding organic loading rates (OLR) ranged from 4.2 to 12.8 gVS/L(reactor) d. The findings revealed that highest system efficiency was achieved at an OLR of 11.2 gVS/L(reactor) d (6 days-HRT) with a methane production rate (MPR) and volatile solids (VS) reduction of 2.91 LCH4/L(reactor) d and 57.5%, respectively. The HRT of 5 days was found critical for the studied process, which leads to volatile fatty acids (VFA) accumulation and sharp drop in pH. However, the increase of HRT permits the recovery of system. Copyright © 2015 Elsevier Ltd. All rights reserved.

Development of an estimation model for the evaluation of the energy requirement of dilute acid pretreatments of biomass.

PubMed

Mafe, Oluwakemi A T; Davies, Scott M; Hancock, John; Du, Chenyu

2015-01-01

This study aims to develop a mathematical model to evaluate the energy required by pretreatment processes used in the production of second generation ethanol. A dilute acid pretreatment process reported by National Renewable Energy Laboratory (NREL) was selected as an example for the model's development. The energy demand of the pretreatment process was evaluated by considering the change of internal energy of the substances, the reaction energy, the heat lost and the work done to/by the system based on a number of simplifying assumptions. Sensitivity analyses were performed on the solid loading rate, temperature, acid concentration and water evaporation rate. The results from the sensitivity analyses established that the solids loading rate had the most significant impact on the energy demand. The model was then verified with data from the NREL benchmark process. Application of this model on other dilute acid pretreatment processes reported in the literature illustrated that although similar sugar yields were reported by several studies, the energy required by the different pretreatments varied significantly.

Wide-range simulation of elastoplastic wave fronts and failure of solids under high-speed loading

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

Saveleva, Natalia, E-mail: saveleva@icmm.ru; Bayandin, Yuriy, E-mail: buv@icmm.ru; Naimark, Oleg, E-mail: naimark@icmm.ru

2015-10-27

The aim of this paper is numerical study of deformation processes and failure of vanadium under shock-wave loading. According developed statistical theory of solid with mesoscopic defects the constitutive equations were proposed in terms of two structural variables characterizing behavior of defects ensembles: defect density tensor and structural scaling parameter. On the basis of wide-range constitutive equations the mathematical model of deformation behavior and failure of vanadium was developed taking into account the bond relaxation mechanisms, multistage of fracture and nonlinearity kinetic of defects. Results of numerical simulation allow the description of the major effects of shock wave propagation (elasticmore » precursor decay, grow of spall strength under grow strain rate)« less

Solid propellant rocket motor internal ballistics performance variation analysis, phase 3

NASA Technical Reports Server (NTRS)

Sforzini, R. H.; Foster, W. A., Jr.; Murph, J. E.; Adams, G. W., Jr.

1977-01-01

Results of research aimed at improving the predictability of off nominal internal ballistics performance of solid propellant rocket motors (SRMs) including thrust imbalance between two SRMs firing in parallel are reported. The potential effects of nozzle throat erosion on internal ballistic performance were studied and a propellant burning rate low postulated. The propellant burning rate model when coupled with the grain deformation model permits an excellent match between theoretical results and test data for the Titan IIIC, TU455.02, and the first Space Shuttle SRM (DM-1). Analysis of star grain deformation using an experimental model and a finite element model shows the star grain deformation effects for the Space Shuttle to be small in comparison to those of the circular perforated grain. An alternative technique was developed for predicting thrust imbalance without recourse to the Monte Carlo computer program. A scaling relationship used to relate theoretical results to test results may be applied to the alternative technique of predicting thrust imbalance or to the Monte Carlo evaluation. Extended investigation into the effect of strain rate on propellant burning rate leads to the conclusion that the thermoelastic effect is generally negligible for both steadily increasing pressure loads and oscillatory loads.

Thermal Processing of PVP- and HPMC-Based Amorphous Solid Dispersions.

PubMed

LaFountaine, Justin S; Prasad, Leena Kumari; Brough, Chris; Miller, Dave A; McGinity, James W; Williams, Robert O

2016-02-01

Thermal processing technologies continue to gain interest in pharmaceutical manufacturing. However, the types and grades of polymers that can be utilized in common thermal processing technologies, such as hot-melt extrusion (HME), are often limited by thermal or rheological factors. The objectives of the present study were to compare and contrast two thermal processing methods, HME and KinetiSol® Dispersing (KSD), and investigate the influence of polymer type, polymer molecular weight, and drug loading on the ability to produce amorphous solid dispersions (ASDs) containing the model compound griseofulvin (GRIS). Dispersions were analyzed by a variety of imaging, solid-state, thermal, and solution-state techniques. Dispersions were prepared by both HME and KSD using polyvinylpyrrolidone (PVP) K17 or hydroxypropyl methylcellulose (HPMC) E5. Dispersions were only prepared by KSD using higher molecular weight grades of HPMC and PVP, as these could not be extruded under the conditions selected. Powder X-ray diffraction (PXRD) analysis showed that dispersions prepared by HME were amorphous at 10% and 20% drug load; however, it showed significant crystallinity at 40% drug load. PXRD analysis of KSD samples showed all formulations and drug loads to be amorphous with the exception of trace crystallinity seen in PVP K17 and PVP K30 samples at 40% drug load. These results were further supported by other analytical techniques. KSD produced amorphous dispersions at higher drug loads than could be prepared by HME, as well as with higher molecular weight polymers that were not processable by HME, due to its higher rate of shear and torque output.

Recovery of energy and nutrient resources from cattle paunch waste using temperature phased anaerobic digestion.

PubMed

Jensen, Paul D; Mehta, Chirag M; Carney, Chris; Batstone, D J

2016-05-01

Cattle paunch is comprised of partially digested cattle feed, containing mainly grass and grain and is a major waste produced at cattle slaughterhouses contributing 20-30% of organic matter and 40-50% of P waste produced on-site. In this work, Temperature Phased Anaerobic Digestion (TPAD) and struvite crystallization processes were developed at pilot-scale to recover methane energy and nutrients from paunch solid waste. The TPAD plant achieved a maximum sustainable organic loading rate of 1-1.5kgCODm(-3)day(-1) using a feed solids concentration of approximately 3%; this loading rate was limited by plant engineering and not the biology of the process. Organic solids destruction (60%) and methane production (230LCH4kg(-1) VSfed) achieved in the plant were similar to levels predicted from laboratory biochemical methane potential (BMP) testing. Model based analysis identified no significant difference in batch laboratory parameters vs pilot-scale continuous parameters, and no change in speed or extent of degradation. However the TPAD process did result in a degree of process intensification with a high level of solids destruction at an average treatment time of 21days. Results from the pilot plant show that an integrated process enabled resource recovery at 7.8GJ/dry tonne paunch, 1.8kgP/dry tonne paunch and 1.0kgN/dry tonne paunch. Copyright © 2016 Elsevier Ltd. All rights reserved.

Experimental evaluation of 150-millimeter bore ball bearing to 3 million DN using either solid or drilled balls

NASA Technical Reports Server (NTRS)

Scibbe, H. W.; Munson, H. E.

1973-01-01

Seven 150-mm bore ball bearings were run under 8900 Newton (2000 lb) thrust load at speeds from 6670 to 20,000 rpm (1 to 3 million DN). Four of the bearings had conventional solid balls and three bearing had drilled (cylindrically hollow) balls with 50 percent mass reduction. The bearings were under-race cooled and slot-lubricated with Type 2 ester oil at flow rates from 4.35 to 5.80 liters per minute (1.15 to 1.57 gal min). Friction torque and temperatures were measured on all bearings. No significant difference in torque was noted, between the solid and drilled ball bearings. One bearing of each type was rerun at 17,800 Newtons (4000 lb) thrust load. The solid ball bearings performed satisfactorily at 3 million DN. However, at about 2 million DN the drilled ball bearing experienced a broken ball and cracks appeared in two other balls as the result of flexure fatigue. Metallurgical examination of the cracked balls indicated a brittle structure in the bore of the drilled balls.

Stall/surge dynamics of a multi-stage air compressor in response to a load transient of a hybrid solid oxide fuel cell-gas turbine system

NASA Astrophysics Data System (ADS)

Azizi, Mohammad Ali; Brouwer, Jacob

2017-10-01

A better understanding of turbulent unsteady flows in gas turbine systems is necessary to design and control compressors for hybrid fuel cell-gas turbine systems. Compressor stall/surge analysis for a 4 MW hybrid solid oxide fuel cell-gas turbine system for locomotive applications is performed based upon a 1.7 MW multi-stage air compressor. Control strategies are applied to prevent operation of the hybrid SOFC-GT beyond the stall/surge lines of the compressor. Computational fluid dynamics tools are used to simulate the flow distribution and instabilities near the stall/surge line. The results show that a 1.7 MW system compressor like that of a Kawasaki gas turbine is an appropriate choice among the industrial compressors to be used in a 4 MW locomotive SOFC-GT with topping cycle design. The multi-stage radial design of the compressor enhances the ability of the compressor to maintain air flow rate during transient step-load changes. These transient step-load changes are exhibited in many potential applications for SOFC/GT systems. The compressor provides sustained air flow rate during the mild stall/surge event that occurs due to the transient step-load change that is applied, indicating that this type of compressor is well-suited for this hybrid application.

Influence of organic loading rate on methane production in a CSTR from physicochemical sludge generated in a poultry slaughterhouse.

PubMed

López-Escobar, Luis A; Martínez-Hernández, Sergio; Corte-Cano, Grisel; Méndez-Contreras, Juan M

2014-01-01

The influence of the increase of the organic loading rate (OLR) on methane production in a continuous stirred-tank reactor (CSTR) from physicochemical sludge generated in a poultry slaughterhouse was evaluated. Total solid (TS) to obtain OLR of 1, 5, 10 and 15 g VS L(-1) day(-1), with hydraulic retention times of 29, 6, 6 and 4, respectively, were conditioned. The results showed a decrease in pH levels and an increase in the theoretical volatile fatty acids (VFA). While the yield of methane production decreased from 0.48 to 0.10 LCH4/g VSremoved, respectively, the OLR-10 managed on average 38% removal of volatile solids (VS) and a yield biogas production of 0.81 Lbiogas g(-1) VSremoved and 1.35 L day(-1). This suggests that the OLR increases in an anaerobic system from physicochemical sludge only inhibits the methanogenic metabolism, because there is still substrate consumption and biogas production.

Estimated dissolved-solids loads and trends at selected streams in and near the Uinta Basin, Utah, Water Years 1989–2013

USGS Publications Warehouse

Thiros, Susan A.

2017-03-23

The U.S. Geological Survey (USGS), in cooperation with the Colorado River Basin Salinity Control Forum, studied trends in dissolved-solids loads at selected sites in and near the Uinta Basin, Utah. The Uinta Basin study area includes the Duchesne River Basin and the Middle Green River Basin in Utah from below Flaming Gorge Reservoir to the town of Green River.Annual dissolved-solids loads for water years (WY) 1989 through 2013 were estimated for 16 gaging stations in the study area using streamflow and water-quality data from the USGS National Water Information System database. Eight gaging stations that monitored catchments with limited or no agricultural land use (natural subbasins) were used to assess loads from natural sources. Four gaging stations that monitored catchments with agricultural land in the Duchesne River Basin were used to assess loads from agricultural sources. Four other gaging stations were included in the dissolved-solids load and trend analysis to help assess the effects of agricultural areas that drain to the Green River in the Uinta Basin, but outside of the Duchesne River Basin.Estimated mean annual dissolved-solids loads for WY 1989–2013 ranged from 1,520 tons at Lake Fork River above Moon Lake, near Mountain Home, Utah (UT), to 1,760,000 tons at Green River near Green River, UT. The flow-normalized loads at gaging stations upstream of agricultural activities showed no trend or a relatively small change. The largest net change in modeled flow-normalized load was -352,000 tons (a 17.8-percent decrease) at Green River near Green River, UT.Annual streamflow and modeled dissolved-solids loads at the gaging stations were balanced between upstream and downstream sites to determine how much water and dissolved solids were transported to the Duchesne River and a section of the Green River, and how much was picked up in each drainage area. Mass-balance calculations of WY 1989–2013 mean annual dissolved-solids loads at the studied sites show that Green River near Jensen, UT, accounts for 64 percent of the load in the river at Green River, UT, while the Duchesne River and White River contribute 10 and 13 percent, respectively.Annual streamflow and modeled dissolved-solids loads at the gaging stations were balanced between upstream and downstream sites to determine how much water and dissolved solids were transported to the Duchesne River and a section of the Green River, and how much was picked up in each drainage area. Mass-balance calculations of WY 1989–2013 mean annual dissolved-solids loads at the studied sites show that Green River near Jensen, UT, accounts for 64 percent of the load in the river at Green River, UT, while the Duchesne River and White River contribute 10 and 13 percent, respectively.The flow-normalized dissolved-solids loads estimated at Duchesne River near Randlett, UT, and White River near Watson, UT, decreased by 68,000 and 55,300 tons, or 27.8 and 20.8 percent respectively, when comparing 1989 to 2013. The drainage basins for both rivers have undergone salinity-control projects since the early 1980s to reduce the dissolved-solids load entering the Colorado River. Approximately 19 percent of the net change in flow-normalized load at Green River at Green River, UT, is from changes in load modeled at Duchesne River near Randlett, UT, and 16 percent from changes in load modeled at White River near Watson, UT. The net change in flow-normalized load estimated at Green River near Greendale, UT, for WY 1989–2013 accounts for about 45 percent of the net change estimated at Green River at Green River, UT.Mass-balance calculations of WY 1989–2013 mean annual dissolved-solids loads at the studied sites in the Duchesne River Basin show that 75,400 tons or 44 percent of the load at the Duchesne River near Randlett, UT, gaging station was not accounted for at any of the upstream gages. Most of this unmonitored load is derived from tributary inflow, groundwater discharge, unconsumed irrigation water, and irrigation tail water.A mass balance of WY 1989–2013 flow-normalized loads estimated at sites in the Duchesne River Basin indicates that the flow-normalized load of unmonitored inflow to the Duchesne River between the Myton and Randlett gaging stations decreased by 38 percent. The total net decrease in flow-normalized load calculated for unmonitored inflow in the drainage basin accounts for 94 percent of the decrease in WY 1989–2013 flow-normalized load modeled at the Duchesne River near Randlett, UT, gaging station. Irrigation improvements in the drainage basin have likely contributed to the decrease in flow-normalized load.Reductions in dissolved-solids load estimated by the Natural Resources Conservation Service (NRCS) and the Bureau of Reclamation (Reclamation) from on- and off-farm improvements in the Uinta Basin totaled about 135,000 tons in 2013 (81,900 tons from on-farm improvements and 53,300 tons from off-farm improvements). The reduction in dissolved-solids load resulting from on- and off-farm improvements facilitated by the NRCS and Reclamation in the Price River Basin from 1989 to 2013 was estimated to be 64,800 tons.The amount of sprinkler-irrigated land mapped in the drainage area or subbasin area for a gaging station was used to estimate the reduction in load resulting from the conversion from flood to sprinkler irrigation. Sprinkler-irrigated land mapped in the Uinta Basin totaled 109,630 acres in 2012. Assuming conversion to wheel-line sprinklers, a reduction in dissolved-solids load in the Uinta Basin of 95,800 tons in 2012 was calculated using the sprinkler-irrigation acreage and a pre-salinity-control project dissolved-solids yield of 1.04 tons per acre.A reduction of 72,800 tons in dissolved-solids load from irrigation improvements was determined from sprinkler-irrigated lands in the Ashley Valley and Jensen, Pelican Lake, and Pleasant Valley areas (mapped in 2012); and in the Price River Basin (mapped in 2011). This decrease in dissolved-solids load is 8,800 tons more than the decrease in unmonitored flow-normalized dissolved-solids load (-64,000 tons) determined for the Green River between the Jensen and Green River gaging stations.The net WY 1989–2013 change in flow-normalized dissolved-solids load at the Duchesne River near Randlett, UT, and the Green River between the Jensen and Green River, UT, gaging stations determined from mass-balance calculations was compared to reported reductions in dissolved-solids load from on- and off-farm improvements and estimated reductions in load determined from mapped sprinkler-irrigated areas in the Duchesne River Basin and the area draining to the Green River between the Jensen and Green River gaging stations. The combined NRCS and Reclamation estimates of reduction in dissolved-solids load from on- and off-farm improvements in the study area (200,000 tons) is more than the reduction in load estimated using the acreage with sprinkler improvements (136,000 tons) or the mass-balance of flow-normalized load (132,000 tons).

Pollutant loading from low-density residential neighborhoods in California.

PubMed

Bale, Andrew E; Greco, Steven E; Pitton, Bruno J L; Haver, Darren L; Oki, Lorence R

2017-08-01

This paper presents a comparison of pollutant load estimations for runoff from two geographically distinct residential suburban neighborhoods in northern and southern California. The two neighborhoods represent a single urban land use type: low-density residential in small catchments (<0.3 km 2 ) under differing regional climates and irrigation practices. Pollutant loads of pesticides, nutrients, and drinking water constituents of concern are estimated for both storm and non-storm runoff. From continuous flow monitoring, it was found that a daily cycle of persistent runoff that peaks mid-morning occurs at both sites. These load estimations indicate that many residential neighborhoods in California produce significant non-storm pollutant loads year-round. Results suggest that non-storm flow accounted for 47-69% of total annual runoff and significantly contributed to annual loading rates of most nutrients and pesticides at both sites. At the Southern California site, annual non-storm loads are 1.2-10 times higher than storm loads of all conventional constituents and nutrients with one exception (total suspended solids). At the Northern California site, annual storm loads range from 51 to 76% of total loads for all conventional constituents and nutrients with one exception (total dissolved solids). Non-storm yields of pesticides at the Southern California site range from 1.3-65 times higher than those at the Northern California site. The disparity in estimated pollutant loads between the two sites indicates large potential variation from site-to-site within the state and suggests neighborhoods in drier and milder climates may produce significantly larger non-storm loads due to persistent dry season runoff and year-round pest control.

The role of baseflow in dissolved solids delivery to streams in the Upper Colorado River Basin

NASA Astrophysics Data System (ADS)

Rumsey, C.; Miller, M. P.; Schwarz, G. E.; Susong, D.

2017-12-01

Salinity has a major effect on water users in the Colorado River Basin, estimated to cause almost $300 million per year in economic damages. The Colorado River Basin Salinity Control Program implements and manages projects to reduce salinity (dissolved solids) loads, investing millions of dollars per year in irrigation upgrades, canal projects, and other mitigation strategies. To inform and improve mitigation efforts, there is a need to better understand sources of salinity to streams and how salinity has changed over time. This study explores salinity in baseflow, or groundwater discharge to streams, to assess whether groundwater is a significant contributor of dissolved solids to streams in the Upper Colorado River Basin (UCRB). Chemical hydrograph separation was used to estimate long-term mean annual baseflow discharge and baseflow dissolved solids loads at stream gages (n=69) across the UCRB. On average, it is estimated that 89% of dissolved solids loads originate from the baseflow fraction of streamflow. Additionally, a statistical trend analysis using weighted regressions on time, discharge, and season was used to evaluate changes in baseflow dissolved solids loads in streams with data from 1987 to 2011 (n=29). About two-thirds (62%) of these streams showed statistically significant decreasing trends in baseflow dissolved solids loads. At the two most downstream sites, Green River at Green River, UT and Colorado River at Cisco, UT, baseflow dissolved solids loads decreased by a combined 780,000 metric tons, which is approximately 65% of the estimated basin-scale decrease in total dissolved solids loads in the UCRB attributed to salinity control efforts. Results indicate that groundwater discharged to streams, and therefore subsurface transport processes, play a large role in delivering dissolved solids to streams in the UCRB. Decreasing trends in baseflow dissolved solids loads suggest that salinity mitigation projects, changes in land use, and/or climate are decreasing salinity in groundwater transported to streams.

Aqueous extraction kinetics of soluble solids, phenolics and flavonoids from sage (Salvia fruticosa Miller) leaves.

PubMed

Torun, Mehmet; Dincer, Cuneyt; Topuz, Ayhan; Sahin-Nadeem, Hilal; Ozdemir, Feramuz

2015-05-01

In the present study, aqueous extraction kinetics of total soluble solids (TSS), total phenolic content (TPC) and total flavonoid content (TFC) from Salvia fruticosa leaves were investigated throughout 150 min. of extraction period against temperature (60-80 °C), particle size (2-8 mm) and loading percentage (1-4 %). The extract yielded 25 g/100 g TSS which contained 30 g/100 g TPC and 25 g/100 g TFC. The extraction data in time course fit with reversible first order kinetic model. All tested variables showed significant effect on the estimated kinetic parameters except equilibrium concentration. Increasing the extraction temperature resulted high extraction rate constants and equilibrium concentrations of the tested variables notably above 70 °C. By using the Arrhenius relationship, activation energy of the TSS, TPC and TFC were determined as 46.11 ± 5.61, 36.80 ± 3.12 and 33.52 ± 2.23 kj/mol, respectively. By decreasing the particle size, the extraction rate constants and diffusion coefficients exponentially increased whereas equilibrium concentrations did not change significantly. The equilibrium concentrations of the tested parameters showed linear behavior with increasing the loading percentage of the sage, however; the change in extraction rates did not show linear behavior due to submerging effect of 4 % loading.

Investigation of Anion-Exchange and Immunoaffinity Particle-Loaded Membranes for the Isolation of Charged Organic Analytes from Water

USGS Publications Warehouse

Dombrowski, T.R.; Wilson, G.S.; Thurman, E.M.

1998-01-01

Anion-exchange and immunoaffinity particle loaded membranes (PLMs) were investigated as a mechanism for the isolation of charged organic analytes from water. Kinetic properties determined theoretically included dynamic capacity, pressure drop (??P), residence and diffusion times (Tr, Td), and total membrane porosity (???T). These properties were confirmed through experimental evaluation, and the PLM method showed significant improvement over conventional solid-phase extraction (SPE) and ion-exchange formats. Recoveries of more than 90% were observed for a variety of test compounds at flow rates up to 70 mL/min (equipment-limited maximum flow rate). A fast-flow immunoaffinity column was developed using antibodies (Abs) attached to the PLMs. Reproducible recoveries (88% ?? 4%) were observed at flow rates up to 70 mL/min for the antibody (Ab)-loaded PLMs. Findings indicate increased selectivity over anion-exchange PLMs and conventional SPE or ion-exchange methods and rapid Ab-antigen binding rates given the excellent mass-transfer characteristics of the PLMs.

Complete solids retention activated sludge process.

PubMed

Amanatidou, E; Samiotis, G; Trikoilidou, E; Pekridis, G; Tsikritzis, L

2016-01-01

In a slaughterhouse's full-scale extended aeration activated sludge wastewater treatment plant (WWTP), operating under complete solids retention time, the evolution of mixed liquor suspended solids (MLSS) and mixed liquor volatile suspended solids (MLVSS) concentration, food to micro-organisms ratio (F/M) and substrate utilization rate (SUR) were studied for over a year. Biomass growth phases in correlation to sludge biological and morphological characteristics were studied. Three distinguished growth phases were observed during the 425 days of monitoring. The imposed operational conditions led the process to extended biomass starvation conditions, minimum F/M, minimum SUR and predator species growth. MLSS and MLVSS reached a stabilization phase (plateau phase) where almost zero sludge accumulation was observed. The concept of degradation of the considered non-biodegradable particulate compounds in influent and in biomass (cell debris) was also studied. Comparison of evolution of observed sludge yields (Yobs) in the WWTP with Yobs predictions by activated sludge models verified the degradation concept for the considered non-biodegradable compounds. Control of the sedimentation process was achieved, by predicting the solids loading rate critical point using state point analysis and stirred/unstirred settling velocity tests and by applying a high return activated sludge rate. The nitrogen gas related sedimentation problems were taken into consideration.

Room-temperature synthesis of Zn(0.80)Cd(0.20)S solid solution with a high visible-light photocatalytic activity for hydrogen evolution.

PubMed

Wang, Dong-Hong; Wang, Lei; Xu, An-Wu

2012-03-21

Visible light photocatalytic H(2) production from water splitting is of great significance for its potential applications in converting solar energy into chemical energy. In this study, a series of Zn(1-x)Cd(x)S solid solutions with a nanoporous structure were successfully synthesized via a facile template-free method at room temperature. The obtained solid solutions were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS) and N(2) adsorption-desorption analysis. The solid solutions show efficient photocatalytic activity for H(2) evolution from aqueous solutions containing sacrificial reagents S(2-) and SO(3)(2-) under visible-light irradiation without a Pt cocatalyst, and loading of the Pt cocatalyst further improves the visible-light photocatalytic activity. The optimal photocatalyst with x = 0.20 prepared at pH = 7.3 displays the highest activity for H(2) evolution. The bare and 0.25 wt% Pt loaded Zn(0.80)Cd(0.20)S nanoparticles exhibit a high H(2) evolution rate of 193 μmol h(-1) and 458 μmol h(-1) under visible-light irradiation (λ ≥ 420 nm), respectively. In addition, the bare and 0.25 wt% Pt loaded Zn(0.80)Cd(0.20)S catalysts show a high H(2) evolution rate of 252 and 640 μmol h(-1) under simulated solar light irradiation, respectively. Moreover, the Zn(0.80)Cd(0.20)S catalyst displays a high photocatalytic stability for H(2) evolution under long-term light irradiation. The incorporation of Cd in the solid solution leads to the visible light absorption, and the high content of Zn in the solid solution results in a relatively negative conduction band, a modulated band gap and a rather wide valence bandwidth, which are responsible for the excellent photocatalytic performance of H(2) production and for the high photostability. This journal is © The Royal Society of Chemistry 2012

Comparing the fermentation performance of Escherichia coli KO11, Saccharomyces cerevisiae 424A(LNH-ST) and Zymomonas mobilis AX101 for cellulosic ethanol production

PubMed Central

2010-01-01

Background Fermentations using Escherichia coli KO11, Saccharomyces cerevisiae 424A(LNH-ST), and Zymomonas mobilis AX101 are compared side-by-side on corn steep liquor (CSL) media and the water extract and enzymatic hydrolysate from ammonia fiber expansion (AFEX)-pretreated corn stover. Results The three ethanologens are able produce ethanol from a CSL-supplemented co-fermentation at a metabolic yield, final concentration and rate greater than 0.42 g/g consumed sugars, 40 g/L and 0.7 g/L/h (0-48 h), respectively. Xylose-only fermentation of the tested ethanologenic bacteria are five to eight times faster than 424A(LNH-ST) in the CSL fermentation. All tested strains grow and co-ferment sugars at 15% w/v solids loading equivalent of ammonia fiber explosion (AFEX)-pretreated corn stover water extract. However, both KO11 and 424A(LNH-ST) exhibit higher growth robustness than AX101. In 18% w/w solids loading lignocellulosic hydrolysate from AFEX pretreatment, complete glucose fermentations can be achieved at a rate greater than 0.77 g/L/h. In contrast to results from fermentation in CSL, S. cerevisiae 424A(LNH-ST) consumed xylose at the greatest extent and rate in the hydrolysate compared to the bacteria tested. Conclusions Our results confirm that glucose fermentations among the tested strains are effective even at high solids loading (18% by weight). However, xylose consumption in the lignocellulosic hydrolysate is the major bottleneck affecting overall yield, titer or rate of the process. In comparison, Saccharomyces cerevisiae 424A(LNH-ST) is the most relevant strains for industrial production for its ability to ferment both glucose and xylose from undetoxified and unsupplemented hydrolysate from AFEX-pretreated corn stover at high yield. PMID:20507563

High temperature lubricating process

DOEpatents

Taylor, R.W.; Shell, T.E.

1979-10-04

It has been difficult to provide adequate lubrication for load bearing, engine components when such engines are operating in excess of about 475/sup 0/C. The present invention is a process for providing a solid lubricant on a load bearing, solid surface, such as in an engine being operated at temperatures in excess of about 475/sup 0/C. The process comprises contacting and maintaining the following steps: a gas phase is provided which includes at least one component reactable in a temperature dependent reaction to form a solid lubricant; the gas phase is contacted with the load bearing surface; the load bearing surface is maintained at a temperature which causes reaction of the gas phase component and the formation of the solid lubricant; and the solid lubricant is formed directly on the load bearing surface. The method is particularly suitable for use with ceramic engines.

High temperature lubricating process

DOEpatents

Taylor, Robert W.; Shell, Thomas E.

1982-01-01

It has been difficult to provide adaquate lubrication for load bearing, engine components when such engines are operating in excess of about 475.degree. C. The present invention is a process for providing a solid lubricant on a load bearing, solid surface (14), such as in an engine (10) being operated at temperatures in excess of about 475.degree. C. The process comprises contacting and maintaining steps. A gas phase (42) is provided which includes at least one component reactable in a temperature dependent reaction to form a solid lubricant. The gas phase is contacted with the load bearing surface. The load bearing surface is maintained at a temperature which causes reaction of the gas phase component and the formation of the solid lubricant. The solid lubricant is formed directly on the load bearing surface. The method is particularly suitable for use with ceramic engines.

Hot-Tearing Assessment of Multicomponent Nongrain-Refined Al-Cu Alloys for Permanent Mold Castings Based on Load Measurements in a Constrained Mold

NASA Astrophysics Data System (ADS)

Sabau, Adrian S.; Mirmiran, Seyed; Glaspie, Christopher; Li, Shimin; Apelian, Diran; Shyam, Amit; Allen Haynes, J.; Rodriguez, Andres F.

2018-06-01

The hot-tearing resistance of multicomponent Al-Cu alloys during permanent mold casting was investigated using a constrained permanent mold in which the load and temperature were measured. The nominal Cu composition was varied from 5 to 8 wt pct. Casting experiments were conducted without adding any grain-refining inoculants. The following variables, which were obtained from the measured load data during casting, were considered to assess the hot-tearing resistance of the Al-Cu multicomponent alloys: "V"-like signature in the load rate variation, load at solidus point, and load rate average over the freezing range. In addition, a hot-tearing criterion based on the variation of the fraction of solid in the late stages of solidification was used. It was found that all criteria considered can accurately predict the alloys with the lowest and highest hot-tear resistance, respectively. It was found that the rate of measured load during casting could be used to indicate substantial hot tearing. However, the load rate variation could not be used to detect when small hot tears were present. Among all the criteria considered, the load at the solidus point shows an excellent agreement with experimentally observed hot-tearing resistance for all but one alloy. The poorly resistant hot-tearing alloys exhibited mainly coarse columnar grains while the most hot-tearing resistant alloys exhibited a much more refined grain microstructure. This is the first study in which good hot-tear resistance is demonstrated for multicomponent Al-Cu alloys with nominal Cu content greater than 7 wt pct.

Production of biogas from municipal solid waste with domestic sewage.

PubMed

Elango, D; Pulikesi, M; Baskaralingam, P; Ramamurthi, V; Sivanesan, S

2007-03-06

In this study, experiments were conducted to investigate the production of biogas from municipal solid waste (MSW) and domestic sewage by using anaerobic digestion process. The batch type of reactor was operated at room temperature varying from 26 to 36 degrees C with a fixed hydraulic retention time (HRT) of 25 days. The digester was operated at different organic feeding rates of 0.5, 1.0, 2.3, 2.9, 3.5 and 4.3kg of volatile solids (VS)/m(3) of digester slurry per day. Biogas generation was enhanced by the addition of domestic sewage to MSW. The maximum biogas production of 0.36m(3)/kg of VS added per day occurred at the optimum organic feeding rate of 2.9kg of VS/m(3)/day. The maximum reduction of total solids (TS) (87.6%), VS (88.1%) and chemical oxygen demand (COD) (89.3%) occurred at the optimum organic loading rate of 2.9kg of VS/m(3)/day. The quality of biogas produced during anaerobic digestion process was 68-72%.

Fundamental aspects of polyimide dry film and composite lubrication: A review

NASA Technical Reports Server (NTRS)

Fusaro, R. L.

1982-01-01

The tribological properties of polyimide dry films and composites are reviewed. Friction coefficients, wear rates, transfer film characteristics, wear surface morphology, and possible wear mechanisms of several different polyimide films, polyimide-bonded solid lubricants, polyimide solid bodies, and polyimide composites are discussed. Such parameters as temperature, type of atmosphere, load, contact stress, and specimen configuration are investigated. Data from an accelerated test device (Pin-on-Disk) are compared to similar data obtained from an end use application test device (plain spherical bearing).

Vapor Grown Carbon Fiber/Phenolic Matrix Composites for Rocket Nozzles and Heat Shields

NASA Technical Reports Server (NTRS)

Patton, R. D.; Pittman, C. U., Jr.; Wang, L.; Day, A.; Hill, J. R.

2001-01-01

The ablation and mechanical and thermal properties of vapor grown carbon fiber (VGCF)/phenolic resin composites were evaluated to determine the potential of using this material in solid rocket motor nozzles. Composite specimens with varying VGCF loading (30%-50% wt) including one sample with ex-rayon carbon fiber plies were prepared and exposed to a plasma torch for 20 s with a heat flux of 16.5 MW/sq m at approximately 1650 C. Low erosion rates and little char formation were observed, confirming that these materials were promising for rocket motor nozzle materials. When fiber loadings increased, mechanical properties and ablative properties improved. The VGCF composites had low thermal conductivities (approximately 0.56 W/m-C) indicating they were good insulating materials. If a 65% fiber loading in VGCF composite can be achieved, then ablative properties are projected to be comparable to or better than the composite material currently used on the Space Shuttle Reusable Solid Rocket Motor (RSRM).

Evaluation of drilled-ball bearings at DN values to three million. 1: Variable oil flow tests

NASA Technical Reports Server (NTRS)

Holmes, P. W.

1932-01-01

Two 125-mm-bore solid ball bearings and two similar drilled ball bearings were operated at speeds up to 24,000 rpm (3.0 million DN) with a 13,000 newton (3000 lb) thrust load. The oil flow rate was varied from 0.045 to 0.121 kilograms per second (6 to 16 lb/min). The solid ball bearings operated satisfactorily over the entire range of conditions. The drilled ball bearing experienced cage rub with marginal lubrication at 0.045 kilograms per second (6 lb/min). The drilled ball bearing generally ran cooler than the solid ball bearings.

A comparison of simple rheological parameters and simulation data for Zymomonas mobilis fermentation broths with high substrate loading in a 3-L bioreactor.

PubMed

Um, Byung-Hwan; Hanley, Thomas R

2008-03-01

Traditionally, as much as 80% or more of an ethanol fermentation broth is water that must be removed. This mixture is not only costly to separate but also produces a large aqueous stream that must then be disposed of or recycled. Integrative approaches to water reduction include increasing the biomass concentration during fermentation. In this paper, experimental results are presented for the rheological behavior of high-solids enzymatic cellulose hydrolysis and ethanol fermentation for biomass conversion using Solka Floc as the model feedstock. The experimental determination of the viscosity, shear stress, and shear rate relationships of the 10 to 20% slurry concentrations with constant enzyme concentrations are performed with a variable speed rotational viscometer (2.0 to 200 rpm) at 40 degrees C. The viscosities of enzymatic suspension observed were in range of 0.0418 to 0.0144, 0.233 to 0.0348, and 0.292 to 0.0447 Pa s for shear rates up to 100 reciprocal seconds at 10, 15, and 20% initial solids (w/v), respectively. Computational fluid dynamics analysis of bioreactor mixing demonstrates the change in bioreactor mixing with increasing biomass concentration. The portion-loading method is shown to be effective for processing high-solids slurries.

Anaerobic digestion of pressed off leachate from the organic fraction of municipal solid waste

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

Nayono, Satoto E.; Institute of Biology for Engineers and Biotechnology of Wastewater, University of Karlsruhe, Am Fasanengarten, 76131 Karlsruhe; Winter, Josef, E-mail: josef.winter@iba.uka.d

2010-10-15

A highly polluted liquid ('press water') was obtained from the pressing facility for the organic fraction of municipal solid waste in a composting plant. Methane productivity of the squeezed-off leachate was investigated in batch assays. To assess the technical feasibility of 'press water' as a substrate for anaerobic digestion, a laboratory-scale glass column reactor was operated semi-continuously at 37 {sup o}C. A high methane productivity of 270 m{sup -3} CH{sub 4} ton{sup -1} COD{sub added} or 490 m{sup -3} CH{sub 4} ton{sup -1} VS{sub added} was achieved in the batch experiment. The semi-continuously run laboratory-scale reactor was initially operated atmore » an organic loading rate of 10.7 kg COD m{sup -3} d{sup -1}. The loading was increased to finally 27.7 kg COD m{sup -3} d{sup -1}, corresponding to a reduction of the hydraulic retention time from initially 20 to finally 7.7 days. During the digestion, a stable elimination of organic material (measured as COD elimination) of approximately 60% was achieved. Linearly with the increment of the OLR, the volumetric methane production of the reactor increased from 2.6 m{sup 3} m{sub reactor}{sup -3} d{sup -1} to 7.1 m{sup 3} m{sub reactor}{sup -3} d{sup -1}. The results indicated that 'press water' from the organic fraction of municipal solid waste was a suitable substrate for anaerobic digestion which gave a high biogas yield even at very high loading rates.« less

Dissolved-solids contribution to the Colorado River from public lands in southeastern Nevada, through September 1993

USGS Publications Warehouse

Westenburg, C.L.

1995-01-01

The Bureau of Land Management administers about 9,300 square miles of public lands in southeastern Nevada that are part of the Colorado River Basin. The U.S. Geological Survey, in cooperation with the Bureau of Land Management, began a 5-year program in October 1988 to assess the contribution of dissolved solids to the fiver from those lands. About 6,200 square miles of public lands are in the Muddy River subbasin in Nevada. The estimated average dissolved-solids load contributed to the Colorado River from those lands was 28,000 tons per year from October 1988 through September 1993. Subsurface flow contributed about 86 percent (24,000 tons per year) of that load. About 730 square miles of public lands in the Las Vegas Wash subbasin contribute dissolved-solids load to the Colorado River. (About 120 square miles of public lands do not contribute to the river.) The estimated average dissolved-solids load contributed to the river from those lands was about 1,300 tons per year from October 1988 through September 1993. Subsurface flow contributed almost all of that load. About 1,100 square miles of public lands are in the Virgin River subbasin in Nevada. The estimated average dissolved- solids load contributed to the Colorado River from Nevada public lands in the subbasin was 8,700 tons per year. Subsurface flow contributed almost the entire load. About 1,200 square miles of Nevada public lands are in ephemeral tributaries that drain direcfly to the Colorado River or its impoundments (Lake Mead and Lake Mobave). The estimated average dissolved-solids load contributed to the river from those lands was 50 tons per year from surface runoff; however, the dissolved-solids load contributed by subsurface flow was not estimated. From October 1992 to September 1993, the Colorado River carried about 6,600,000 tons of dissolved solids past a streamflow gaging station 0.3 mile downstream from Hoover Dam. In contrast, surface runoff and subsurface flow contribute an estimated average dissolved-solids load of 38,000 tons per year from public lands in southeastern Nevada to the Colorado River. Land-management practices probably would not substantially reduce this contribution.

An In Vitro Evaluation of the Loosening of Different Interchangeable Abutments in Internal-Connection-Type Implants.

PubMed

Park, Ji-Man; Baek, Chang-Hyun; Heo, Seong-Joo; Kim, Seong-Kyun; Koak, Jai-Young; Kim, Shin-Koo; Belser, Urs C

The aim of this study was to compare the loosening of interchangeable one-piece abutments connected to internal-connection-type implants after cyclic loading. Four implant abutment groups (n = 7 in each group) with Straumann tissue-level implants were assessed: Straumann solid abutment (group S), Southern Implants solid abutment (group SI), Implant Direct straight abutment (group ID), and Blue Sky Bio regular platform abutment (group BSB). The implant was firmly held in a special jig to ensure fixation. Abutment screws were tightened to manufacturers' recommended torque with a digital torque gauge. The hemispherical loading members were fabricated for the load cell of a universal testing machine to evenly distribute the force on the specimens and to fulfill the ISO 14801:2007 standard. A cyclic loading of 25 N at 30 degrees to the implant's long axis was applied for a duty of a half million cycles. Tightening torques were measured prior to the loading. Removal torques were measured after cyclic loading. The data were analyzed with one-way analysis of variance (ANOVA), and the significance level was set at P < .05. The mean removal torques after cyclic loading were 34.0 ± 1.1 Ncm (group S), 25.0 ± 1.5 Ncm (group SI), 23.9 ± 2.1 Ncm (group ID), and 27.9 ± 1.3 Ncm (group BSB). Removal torques of each group were statistically different in the order of group S > group BSB > groups SI and ID (P < .05). The mean reduction rates were -2.9% ± 3.2% (group S), -21.9% ± 4.8% (group SI), -20.2% ± 7.2% (group ID), and -6.9% ± 4.3% (group BSB) after a half million cycles, respectively. Reduction rates of groups S and BSB were statistically lower than those of groups SI and ID (P < .01). The standard deviation of group S was lower than group BSB. The removal torque of the original Straumann abutment was significantly higher than those of the copy abutments. The reduction rate of the groups S and BSB abutments was lower than those of the other copy abutments.

Comparison of experimental and predicted performance of 150-millimeter-bore solid and drilled ball bearings to 3 million DN

NASA Technical Reports Server (NTRS)

Scibbe, H. W.; Munson, H. E.

1974-01-01

Seven 150-millimeter-bore ball bearings were run under 8900-newton (2000-lbf) thrust load at speeds from 6670 to 20,000 rpm (1 million to 3 million DN). Four of the bearings had conventional solid balls, and three bearings had drilled (cylindrically hollow) balls with 50-percent mass reduction. The bearings were under-race cooled and slot lubricated with a type 2 ester oil at flow rates from 4.35 x 0.001 to 5.94 x 0.001 cubic meter/min (1.15 to 1.57 gal/min). Friction torque and temperature were measured on all bearings. While there was considerable spread in the temperature data, the drilled ball bearings tended to run slightly cooler than the solid ball bearings at higher speeds. No significant difference in torque was noted, however, between the solid and drilled ball bearings. One bearing of each type was rerun at 17,800-newton (4000-lbf) thrust load. The solid ball bearings performed satisfactorily at 3 million DN. However, at about 2 million DN the drilled ball bearing experienced a broken ball, and cracks appeared in other balls as a result of flexure fatigue. Metallurgical examination of the cracked balls indicated a brittle structure in the bore of the drilled balls.

Improvement of the dissolution rate of poorly soluble drugs by solid crystal suspensions.

PubMed

Thommes, Markus; Ely, David R; Carvajal, M Teresa; Pinal, Rodolfo

2011-06-06

We present a novel extrusion based approach where the dissolution rate of poorly soluble drugs (griseofulvin, phenytoin and spironolactone) is significantly accelerated. The drug and highly soluble mannitol are coprocessed in a hot melt extrusion operation. The obtained product is an intimate mixture of the crystalline drug and crystalline excipient, with up to 50% (w/w) drug load. The in vitro drug release from the obtained solid crystalline suspensions is over 2 orders of magnitude faster than that of the pure drug. Since the resulting product is crystalline, the accelerated dissolution rate does not bear the physical stability concerns inherent to amorphous formulations. This approach is useful in situations where the drug is not a good glass former or in cases where it is difficult to stabilize the amorphous drug. Being thermodynamically stable, the dissolution profile and the solid state properties of the product are maintained after storage at 40 °C, 75% RH for at least 90 days.

Enhanced and updated spatially referenced statistical assessment of dissolved-solids load sources and transport in streams of the Upper Colorado River Basin

USGS Publications Warehouse

Miller, Matthew P.; Buto, Susan G.; Lambert, Patrick M.; Rumsey, Christine A.

2017-03-07

Approximately 6.4 million tons of dissolved solids are discharged from the Upper Colorado River Basin (UCRB) to the Lower Colorado River Basin each year. This results in substantial economic damages, and tens of millions of dollars are spent annually on salinity control projects designed to reduce salinity loads in surface waters of the UCRB. Dissolved solids in surface water and groundwater have been studied extensively over the past century, and these studies have contributed to a conceptual understanding of sources and transport of dissolved solids. This conceptual understanding was incorporated into a Spatially Referenced Regressions on Watershed Attributes (SPARROW) model to examine sources and transport of dissolved solids in the UCRB. The results of this model were published in 2009. The present report documents the methods and data used to develop an updated dissolved-solids SPARROW model for the UCRB, and incorporates data defining current basin attributes not available in the previous model, including delineation of irrigated lands by irrigation type (sprinkler or flood irrigation), and calibration data from additional monitoring sites.Dissolved-solids loads estimated for 312 monitoring sites were used to calibrate the SPARROW model, which predicted loads for each of 10,789 stream reaches in the UCRB. The calibrated model provided a good fit to the calibration data as evidenced by R2 and yield R2 values of 0.96 and 0.73, respectively, and a root-mean-square error of 0.47. The model included seven geologic sources that have estimated dissolved-solids yields ranging from approximately 1 to 45 tons per square mile (tons/mi2). Yields generated from irrigated agricultural lands are substantially greater than those from geologic sources, with sprinkler irrigated lands generating an average of approximately 150 tons/mi2 and flood irrigated lands generating between 770 and 2,300 tons/mi2 depending on underlying lithology. The coefficients estimated for six landscape transport characteristics that influence the delivery of dissolved solids from sources to streams, are consistent with the process understanding of dissolved-solids loading to streams in the UCRB.Dissolved-solids loads and the proportion of those loads among sources in the entire UCRB as well as in major tributaries in the basin are reported, as are loads generated from irrigated lands, rangelands, Bureau of Land Management (BLM) lands, and grazing allotments on BLM lands. Model-predicted loads also are compared with load estimates from 1957 and 1991 at selected locations in three divisions of the UCRB. At the basin scale, the model estimates that 32 percent of the dissolved-solids loads are from irrigated agricultural land sources that compose less than 2 percent of the land area in the UCRB. This estimate is less than previously reported estimates of 40 to 45 percent of basin-scale dissolved-solids loads from irrigated agricultural land sources. This discrepancy could be a result of the implementation of salinity control projects in the basin. Notably, results indicate that the conversion of flood irrigated agricultural lands to sprinkler irrigated agricultural lands is a likely process contributing to the temporal decrease in dissolved-solids loads from irrigated lands.

Effects of fruit and vegetable, consumed in solid vs. beverage forms on acute and chronic appetitive responses in lean and obese adults

PubMed Central

Houchins, Jenny A.; Tan, Sze-Yen; Campbell, Wayne W.; Mattes, Richard D.

2012-01-01

Background The effects of fruits and vegetables in solid vs. beverage forms on human appetite and food intake acutely and over eight weeks, are unclear. Methods This 21-week, randomised, crossover study assessed appetitive ratings following the inclusion of fruits and vegetables, in solid and beverage form, into the habitual diet of healthy lean (n=15) and overweight/obese (n=19) adults with low customary consumption. The primary acute outcomes were satiation (amount of challenge meal consumed), satiety (latency of subsequent eating event), and dietary compensation after a 400 kcal fruit preload. Ratings of appetite were also obtained before and after 8 weeks of required increased fruit and vegetable consumption (20% estimated energy requirement). Results Acutely, overweight/obese participants reported smaller reductions of hunger after consuming the fruit preload in beverage compared to solid form (preload × form × BMI effects, P=0.030). Participants also consumed significantly less of a challenge meal (in both gram and energy) after the ingestion of the solid fruit preload (P<0.005). However, the subsequent meal latency was not significantly different between the solid and the beverage fruit preloads. Total daily energy intake was significantly higher when the obese participants consumed the beverage fruit preload compared to the solid (P<0.001). Daily energy intake was markedly, but not significantly, higher among the lean with the beverage versus solid food-form. Hunger and fullness ratings remained stable when participants consumed fruits and vegetables in solid or beverage form for eight weeks each. Conclusion Acute post-ingestive appetitive responses were weaker following consumption of fruits in beverage versus solid food-forms. Consumption of beverage or solid fruit and vegetable food loads for 8 weeks did not chronically alter appetitive responses. PMID:23164702

The global signature of post-1900 land ice wastage on vertical land motion

NASA Astrophysics Data System (ADS)

Riva, Riccardo; Frederikse, Thomas; King, Matt; Marzeion, Ben; van den Broeke, Michiel

2017-04-01

The amount of ice stored on land has strongly declined during the 20th century, and melt rates showed a significant acceleration over the last two decades. Land ice wastage is well known to be one of the main drivers of global mean sea-level rise, as widely discussed in the literature and reflected in the last assessment report of the IPCC. A less obvious effect of melting land ice is the response of the solid earth to mass redistribution on its surface, which, in the first approximation, results in land uplift where the load reduces (e.g., close to the meltwater sources) and land subsidence where the load increases (e.g., under the rising oceans). This effect is nowadays well known within the cryospheric and sea level communities. However, what is often not realized is that the solid earth response is a truly global effect: a localized mass change does cause a large deformation signal in its proximity, but also causes a change of the position of every other point on the Earth's surface. The theory of the Earth's elastic response to changing surface loads forms the basis of the 'sea-level equation', which allows sea-level fingerprints of continental mass change to be computed. In this paper, we provide the first dedicated analysis of global vertical land motion driven by land ice wastage. By means of established techniques to compute the solid earth elastic response to surface load changes and the most recent datasets of glacier and ice sheet mass change, we show that land ice loss currently leads to vertical deformation rates of several tenths of mm per year at mid-latitudes, especially over the Northern Hemisphere where most sources are located. In combination with the improved accuracy of space geodetic techniques (e.g., Global Navigation Satellite Systems), this means that the effect of ice melt is non-negligible over a large part of the continents. In particular, we show how deformation rates have been strongly varying through the last century, which implies that they should be properly modelled before interpreting and extrapolating recent observations of vertical land motion and sea level change.

Hot-Tearing Assessment of Multicomponent Nongrain-Refined Al-Cu Alloys for Permanent Mold Castings Based on Load Measurements in a Constrained Mold

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

Sabau, Adrian S.; Mirmiran, Seyed; Glaspie, Christopher

Here, the hot-tearing resistance of multicomponent Al-Cu alloys during permanent mold casting was investigated using a constrained permanent mold in which the load and temperature were measured. The nominal Cu composition was varied from 5 to 8 wt pct. Casting experiments were conducted without adding any grain-refining inoculants. The following variables, which were obtained from the measured load data during casting, were considered to assess the hot-tearing resistance of the Al-Cu multicomponent alloys: “V”-like signature in the load rate variation, load at solidus point, and load rate average over the freezing range. In addition, a hot-tearing criterion based on themore » variation of the fraction of solid in the late stages of solidification was used. It was found that all criteria considered can accurately predict the alloys with the lowest and highest hot-tear resistance, respectively. It was found that the rate of measured load during casting could be used to indicate substantial hot tearing. However, the load rate variation could not be used to detect when small hot tears were present. Among all the criteria considered, the load at the solidus point shows an excellent agreement with experimentally observed hot-tearing resistance for all but one alloy. The poorly resistant hot-tearing alloys exhibited mainly coarse columnar grains while the most hot-tearing resistant alloys exhibited a much more refined grain microstructure. This is the first study in which good hot-tear resistance is demonstrated for multicomponent Al-Cu alloys with nominal Cu content greater than 7 wt pct.« less

Hot-Tearing Assessment of Multicomponent Nongrain-Refined Al-Cu Alloys for Permanent Mold Castings Based on Load Measurements in a Constrained Mold

DOE PAGES

Sabau, Adrian S.; Mirmiran, Seyed; Glaspie, Christopher; ...

2018-02-16

Here, the hot-tearing resistance of multicomponent Al-Cu alloys during permanent mold casting was investigated using a constrained permanent mold in which the load and temperature were measured. The nominal Cu composition was varied from 5 to 8 wt pct. Casting experiments were conducted without adding any grain-refining inoculants. The following variables, which were obtained from the measured load data during casting, were considered to assess the hot-tearing resistance of the Al-Cu multicomponent alloys: “V”-like signature in the load rate variation, load at solidus point, and load rate average over the freezing range. In addition, a hot-tearing criterion based on themore » variation of the fraction of solid in the late stages of solidification was used. It was found that all criteria considered can accurately predict the alloys with the lowest and highest hot-tear resistance, respectively. It was found that the rate of measured load during casting could be used to indicate substantial hot tearing. However, the load rate variation could not be used to detect when small hot tears were present. Among all the criteria considered, the load at the solidus point shows an excellent agreement with experimentally observed hot-tearing resistance for all but one alloy. The poorly resistant hot-tearing alloys exhibited mainly coarse columnar grains while the most hot-tearing resistant alloys exhibited a much more refined grain microstructure. This is the first study in which good hot-tear resistance is demonstrated for multicomponent Al-Cu alloys with nominal Cu content greater than 7 wt pct.« less

Carrier effects on tertiary nitrifying moving bed biofilm reactor: An examination of performance, biofilm and biologically produced solids.

PubMed

Forrest, Daina; Delatolla, Robert; Kennedy, Kevin

2016-01-01

Increasingly stricter ammonia and nitrogen release regulations with respect to wastewater effluents are creating a need for tertiary treatment systems. The moving bed biofilm reactor (MBBR) is being considered as an upgrade option for an increasing number of wastewater treatment facilities due to its small footprint and ease of operation. Despite the MBBRs creation as a system to remove nitrogen, recent research on MBBR systems showing that the system's performance is directly related to carrier surface area and is irrespective of carrier shape and type has been performed exclusively on chemical oxygen demand (COD) removal systems. Furthermore, the influence of carrier type on the solids produced by MBBR systems has also been exclusively studied for COD removal systems. This work investigates the effects of three specific carrier types on ammonia removal rates, biofilm morphology, along with solids production and settleability of tertiary nitrifying MBBR systems. The study concludes that carrier type has no significant effect on tertiary nitrifying MBBR system performance under steady, moderate loading conditions. The research does however highlight the propensity of greater surface area to volume carriers to become clogged under high loading conditions and that the high surface area carriers investigated in this study required longer adjustment periods to changes in loading after becoming clogged.

Solid dispersion of acetaminophen and poly(ethylene oxide) prepared by hot-melt mixing.

PubMed

Yang, Min; Wang, Peng; Huang, Chien-Yueh; Ku, M Sherry; Liu, Huiju; Gogos, Costas

2010-08-16

In this study, a model drug, acetaminophen (APAP), was melt mixed with poly(ethylene oxide) (PEO) using a Brabender mixer. APAP was found to recrystallize upon cooling to room temperature for all the drug loadings investigated. Higher drug loading leads to faster recrystallization rate. However, the morphology of the recrystallized drug crystals is identical in samples with different drug loadings and does not change with the storage time. To adjust the drug's dissolution rate, nanoclay Cloisite 15A and 30B were added into the binary mixture. The presence of either of the nanoclay dramatically accelerates the drug's recrystallization rate and slows down the drug's releasing rate. The drop of the releasing rate is mainly due to the decrease of wettability, as supported by the contact angle data. Data analysis of the dissolution results suggests that the addition of nanoclays changes the drug's release mechanism from erosion dominant to diffusion dominant. This study suggests that nanoclays may be utilized to tailor the drug's releasing rate and to improve the dosage form's stability by dramatically shortening the lengthy recrystallization process. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Ceramic Near-Net Shaped Processing Using Highly-Loaded Aqueous Suspensions

NASA Astrophysics Data System (ADS)

Rueschhoff, Lisa

Ceramic materials offer great advantages over their metal counterparts, due to their lower density, higher hardness and wear resistance, and higher melting temperatures. However, the use of ceramics in applications where their properties would offer tremendous advantages are often limited due to the difficulty of forming them into complex and near-net shaped parts. Methods that have been developed to injection-mold or cast ceramics into more complicated shapes often use significant volume fractions of a carrier (often greater than 35 vol.% polymer), elevated temperature processing, or less-than-environmentally friendly chemicals where a complex chemical synthesis reaction must be timed perfectly for the approach to work. Furthermore, the continuing maturation of additive manufacturing methods requires a new approach for flowing/placing ceramic powders into useful designs. This thesis addresses the limitations of the current ceramic forming approaches by developing highly-stabilized and therefore high solids loading ceramic suspensions, with the requisite rheology for a variety of complex and near-net shaped forming techniques. Silicon nitride was chosen as a material of focus due to its high fracture toughness compared to other ceramic materials. Designing ceramic suspensions that are flowable at room temperature greatly simplifies processing as neither heating nor cooling are required during forming. Highly-loaded suspensions (>40 vol.%) are desired because all formed ceramic bodies have to be sintered to remove pores. Finally, using aqueous-based suspensions reduces any detrimental effect on the environment and tooling. The preparation of highly-loaded suspensions requires the development of a suitable dispersant through which particle-particle interactions are controlled. However, silicon nitride is difficult to stabilize in water due to complex surface and solution chemistry. In this study, aqueous silicon nitride suspensions up to 45 vol.% solids loading were dispersed using commercially available comb-type copolymer. These copolymers are used as superplasticizers in the concrete industry and are referred to as water-reducing admixtures (WRAs). Four different WRA dispersants were examined and chemical analysis determined that each was made up of a sodium salt of polyacrylic acid (PAA-Na) backbone with neutral polyethylene oxide (PEO) side chains that afford steric stabilization. The general structures of the WRAs were compared to each other by measuring the relative areas of their prominent FTIR peaks and calculating a PAA-Na/PEO peak ratio. Suspensions were made with as-received silicon nitride powders with 5 wt.% aluminum oxide and 5 wt.% yttrium oxide added as sintering aids. Three of the four WRA dispersants studied were able to produce suspensions with 43 vol.% solids loading and 5 vol.% polymer dispersant, while exhibiting a yield-pseudoplastic behavior for shear rates up to 30 s-1. At higher solids loading (45 to 47 vol.%), a shift to shear thickening behavior was observed at a critical shear rate for these WRAs. Those WRAs with a lower PAA-Na/PEO peak ratio displayed better stabilization and diminished shear thickening behavior. The vol.% of the dispersant was optimized, producing yield-pseudoplastic suspensions containing 45 vol.% solids loading with yield stresses less than 75 Pa, no shear thickening behavior, and viscosities less than 75 Pa-s for shear rates in the range of 1 to 30 s-1. Using suspensions prepared with two of the WRAs investigated in this work, silicon nitride near-net shaped parts were formed via a novel injection molding process by loading each suspension in a syringe and injecting them at a controlled rate into a mold. Each suspensions had carefully tailored yield-pseudoplastic rheology such that they can be injection molded at room temperature and low pressures (< 150 kPa). Four suspensions were studied; two different commercially available concrete water-reducing admixtures (WRAs) were used as dispersants with and without a polymer binder (Polyvinylprolidone, PVP) added for rheological modification and improved green body strength. Test bars formed via this process were sintered to high densities (up to 97% TD) without the use of external pressure, and had complete conversion to the desirable beta-Si3N4 phase with high flexural strengths up to 700 MPa. The specimen sets with the smallest average pore size on the fracture surface (77 mum) had the highest average flexural strengths of 573 MPa. The hardness of all specimens was approximately 16 GPa. The water-based suspensions, ease and low cost of processing, and robust mechanical properties obtained demonstrate this as a viable process for the economical and environmentally friendly production of Si3N4 parts. Finally, additive manufacturing was also used as a method to overcome ceramic forming difficulties and to create near-net shaped dense components via room-temperature direct ink writing. In this processes, highly loaded aqueous alumina suspensions were extruded in a layer-by-layer fashion using a low-cost syringe style 3D printer. With alumina as a model material, the effect of solids loading on rheology, specimen uniformity, density, microstructure, and mechanical properties was studied. All suspensions contained a polymer binder ( 5 vol.%), dispersant, and 51 to 58 vol.% alumina powder. Rheological measurements indicated all suspensions to be yield-pseudoplastic, and both yield stress and viscosity were found to increase with increasing alumina solids loading. Shear rates ranging from 19.5 to 24.2 s-1, corresponding to viscosities of 9.8 to 17.2 Pa·s, for the 53 - 56 vol.% alumina suspensions were found to produce the best results for the 1.25 mm tip employed during writing. All parts were sintered to greater than 98% of true density, with grain sizes ranging from 3.2 to 3.7 mum. The average flexure strength, which ranged from 134 to 157 MPa, was not influenced by the alumina solids loading. In limited study, additive manufacturing of silicon nitride suspensions stabilized with a WRA has been established. These processing routes have been proven as low-cost and viable means for producing robust ceramic parts, both of which can be tailored to many systems to expand the use of ceramics materials. Further studies on utilizing the flow stress behavior during both injection molding and direct ink writing could be beneficial in creating ceramic materials with carefully tailored microstructure to increase mechanical performance.

Effect of hydraulic retention time and sludge recirculation on greenhouse gas emission and related microbial communities in two-stage membrane bioreactor treating solid waste leachate.

PubMed

Nuansawan, Nararatchporn; Boonnorat, Jarungwit; Chiemchaisri, Wilai; Chiemchaisri, Chart

2016-06-01

Methane (CH4) and nitrous oxide (N2O) emissions and responsible microorganisms during the treatment of municipal solid waste leachate in two-stage membrane bioreactor (MBR) was investigated. The MBR system, consisting of anaerobic and aerobic stages, were operated at hydraulic retention time (HRT) of 5 and 2.5days in each reactor under the presence and absence of sludge recirculation. Organic and nitrogen removals were more than 80% under all operating conditions during which CH4 emission were found highest under no sludge recirculation condition at HRT of 5days. An increase in hydraulic loading resulted in a reduction in CH4 emission from anaerobic reactor but an increase from the aerobic reactor. N2O emission rates were found relatively constant from anaerobic and aerobic reactors under different operating conditions. Diversity of CH4 and N2O producing microorganisms were found decreasing when hydraulic loading rate to the reactors was increased. Copyright © 2016 Elsevier Ltd. All rights reserved.

Phase Behavior of Ritonavir Amorphous Solid Dispersions during Hydration and Dissolution.

PubMed

Purohit, Hitesh S; Taylor, Lynne S

2017-12-01

The aim of this research was to study the interplay of solid and solution state phase transformations during the dissolution of ritonavir (RTV) amorphous solid dispersions (ASDs). RTV ASDs with polyvinylpyrrolidone (PVP), polyvinylpyrrolidone vinyl acetate (PVPVA) and hydroxypropyl methylcellulose acetate succinate (HPMCAS) were prepared at 10-50% drug loading by solvent evaporation. The miscibility of RTV ASDs was studied before and after exposure to 97% relative humidity (RH). Non-sink dissolution studies were performed on fresh and moisture-exposed ASDs. RTV and polymer release were monitored using ultraviolet-visible spectroscopy. Techniques including fluorescence spectroscopy, confocal imaging, scanning electron microscopy (SEM), atomic force microscopy (AFM), differential scanning calorimetry (DSC) and nanoparticle tracking analysis (NTA) were utilized to monitor solid and the solution state phase transformations. All RTV-PVP and RTV-PVPVA ASDs underwent moisture-induced amorphous-amorphous phase separation (AAPS) on high RH storage whereas RTV-HPMCAS ASDs remained miscible. Non-sink dissolution of PVP- and PVPVA-based ASDs at low drug loadings led to rapid RTV and polymer release resulting in concentrations in excess of amorphous solubility, liquid-liquid phase separation (LLPS) and amorphous nanodroplet formation. High drug loading PVP- and PVPVA-based ASDs did not exhibit LLPS upon dissolution as a consequence of extensive AAPS in the hydrated ASD matrix. All RTV-HPMCAS ASDs led to LLPS upon dissolution. RTV ASD dissolution is governed by a competition between the dissolution rate and the rate of phase separation in the hydrated ASD matrix. LLPS was observed for ASDs where the drug release was polymer controlled and only ASDs that remained miscible during the initial phase of dissolution led to LLPS. Techniques such as fluorescence spectroscopy, confocal imaging and SEM were useful in understanding the phase behavior of ASDs upon hydration and dissolution and were helpful in elucidating the mechanism of generation of amorphous nanodroplets.

Effect of substrate concentration on hydrogen production by photo-fermentation in the pilot-scale baffled bioreactor.

PubMed

Lu, Chaoyang; Zhang, Zhiping; Zhou, Xuehua; Hu, Jianjun; Ge, Xumeng; Xia, Chenxi; Zhao, Jia; Wang, Yi; Jing, Yanyan; Li, Yameng; Zhang, Quanguo

2018-01-01

Effect of substrate concentration on photo-fermentative hydrogen production was studied with a self-designed 4m 3 pilot-scale baffled photo-fermentative hydrogen production reactor (BPHR). The relationships between parameters, such as hydrogen production rate (HPR, mol H 2 /m 3 /d), hydrogen concentration, pH value, oxidation-reduction potential, biomass concentration (volatile suspended solids, VSS) and reducing sugar concentration, during the photo-fermentative hydrogen production process were investigated. The highest HPR of 202.64±8.83mol/m 3 /d was achieved in chamber #3 at a substrate concentration of 20g/L. Hydrogen contents were in the range of 42.19±0.94%-49.71±0.27%. HPR increased when organic loading rate was increased from 3.3 to 20g/L/d, then decreased when organic loading rate was further increased to 25g/L/d. A maximum HPR of 148.65±4.19mol/m 3 /d was obtained when organic loading rate was maintained at 20g/L/d during continuous bio-hydrogen production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydrosalinity studies of the Virgin River, Dixie Hot Springs, and Littlefield Springs, Utah, Arizona, and Nevada

USGS Publications Warehouse

Gerner, Steven J.; Thiros, Susan A.; Gerner, Steven J.; Thiros, Susan A.

2014-01-01

The Virgin River contributes a substantial amount of dissolved solids (salt) to the Colorado River at Lake Mead in the lower Colorado River Basin. Degradation of Colorado River water by the addition of dissolved solids from the Virgin River affects the suitability of the water for municipal, industrial, and agricultural use within the basin. Dixie Hot Springs in Utah are a major localized source of dissolved solids discharging to the Virgin River. The average measured discharge from Dixie Hot Springs during 2009–10 was 11.0 cubic feet per second (ft3/s), and the average dissolved-solids concentration was 9,220 milligrams per liter (mg/L). The average dissolved-solids load—a measurement that describes the mass of salt that is transported per unit of time—from Dixie Hot Springs during this period was 96,200 tons per year (ton/yr). Annual dissolved-solids loads were estimated at 13 monitoring sites in the Virgin River Basin from streamflow data and discrete measurements of dissolved-solids concentrations and (or) specific conductance. Eight of the sites had the data needed to estimate annual dissolved-solids loads for water years (WYs) 1999 through 2010. During 1999–2010, the smallest dissolved-solids loads in the Virgin River were upstream of Dixie Hot Springs (59,900 ton/yr, on average) and the largest loads were downstream of Littlefield Springs (298,200 ton/yr, on average). Annual dissolved-solids loads were smallest during 2002–03, which was a period of below normal precipitation. Annual dissolved-solids loads were largest during 2005—a year that included a winter rain storm that resulted in flooding throughout much of the Virgin River Basin. An average seepage loss of 26.7 ft3/s was calculated from analysis of monthly average streamflow from July 1998 to September 2010 in the Virgin River for the reach that extends from just upstream of the Utah/Arizona State line to just above the Virgin River Gorge Narrows. Seepage losses from three river reaches in the Virgin River Gorge containing known fault zones accounted for about 48 percent of this total seepage loss. An additional seepage loss of 6.7 ft3/s was calculated for the reach of the Virgin River between Bloomington, Utah, and the Utah/Arizona State line. This loss in flow is small compared to total flow in the river and is comparable to the rated error in streamflow measurements in this reach; consequently, it should be used with caution. Littlefield Springs were studied to determine the fraction of its discharge that originates as upstream seepage from the Virgin River and residence time of this water in the subsurface. Geochemical and environmental tracer data from groundwater and surface-water sites in the Virgin River Gorge area suggest that discharge from Littlefield Springs is a mixture of modern (post-1950s) seepage from the Virgin River upstream of the springs and older groundwater from a regional carbonate aquifer. Concentrations of the chlorofluorocarbons (CFCs) CFC-12 and CFC-113, chloride/fluoride and chloride/bromide ratios, and the stable isotope deuterium indicate that water discharging from Littlefield Springs is about 60 percent seepage from the Virgin River and about 40 percent discharge from the regional carbonate aquifer. The river seepage component was determined to have an average subsurface traveltime of about 26 ±1.6 years before discharging at Littlefield Springs. Radiocarbon data for Littlefield Springs suggest groundwater ages from 1,000 to 9,000 years. Because these are mixed waters, the component of discharge from the carbonate aquifer is likely much older than the groundwater ages suggested by the Littlefield Springs samples. If the dissolved-solids load from Dixie Hot Springs to the Virgin River were reduced, the irrigation water subsequently applied to agricultural fields in the St. George and Washington areas, which originates as water from the Virgin River downstream of Dixie Hot Springs, would have a lower dissolved-solids concentration. Dissolved-solids concentrations in excess irrigation water draining from the agricultural fields are about 1,700 mg/L higher than the concentrations in the Virgin River water that is currently (2014) used for irrigation that contains inflow from Dixie Hot Springs; this increase results from evaporative concentration and dissolution of mineral salts in the irrigated agricultural fields. The water samples collected from drains downgradient from the irrigated areas are assumed to include the dissolution of all available minerals precipitated in the soil during the previous irrigation season. Based on this assumption, a change to more dilute irrigation water will not dissolve additional minerals and increase the dissolved-solids load in the drain discharge. Following the hypothetical reduction of salts from Dixie Hot Springs, which would result in more dilute Virgin River irrigation water than is currently used, the dissolution of minerals left in the soil from the previous irrigation season would result in a net increase in dissolved-solids concentrations in the drain discharge, but this increase should only last one irrigation season. After one (or several) seasons of irrigating with more dilute irrigation water, mineral precipitation and subsequent re-dissolution beneath the agricultural fields should be greatly reduced, leading to a reduction in dissolved-solids load to the Virgin River below the agricultural drains. A mass-balance model was used to predict changes in the dissolved-solids load in the Virgin River if the salt discharging from Dixie Hot Springs were reduced or removed. Assuming that 33.4 or 26.7 ft3/s of water seeps from the Virgin River to the groundwater system upstream of the Virgin River Gorge Narrows, the immediate hypothetical reduction in dissolved-solids load in the Virgin River at Littlefield, Arizona is estimated to be 67,700 or 71,500 ton/yr, respectively. The decrease in dissolved-solids load in seepage from the Virgin River to the groundwater system is expected to reduce the load discharging from Littlefield Springs in approximately 26 years, the estimated time lag between seepage from the river and discharge of the seepage water, after subsurface transport, from Littlefield Springs. At that time, the entire reduction in dissolved solids seeping from the Virgin River is expected to be realized as a reduction in dissolved solids discharging from Littlefield Springs, resulting in an additional reduction of 24,700 ton/yr (based on 33.4 ft3/s of seepage loss) or 21,000 ton/yr (based on 26.7 ft3/s of seepage loss) in the river’s dissolved-solids load at Littlefield.

CO2 removal by solid amine sorbents. 1: Experimental studies of amine resin IR-45 with regard to spacecraft applications. 2: Computer program for predicting the transient performance of solid amine sorbent systems

NASA Technical Reports Server (NTRS)

Wright, R. M.; Hwang, K. C.

1973-01-01

The sorbent behavior of solid amine resin IR-45 with regard to potential use in regenerative CO2-removal systems for manned spacecraft is considered. Measurements of equilibrium sorption capacity of IR-45 for water and for CO2 are reported, and the dynamic mass transfer behavior of IR-45 beds is studied under conditions representative of those expected in a manned spacecraft. A digital computer program was written for the transient performance prediction of CO2 removal systems comprised of solid amine beds. Also evaluated are systems employing inorganic molecular-sieve sorbents. Tests show that there is definitely an effect of water loading on the absorption rate.

Slow and fast motion of cracks in inelastic solids. Part 1: Slow growth of cracks in a rate sensitive tresca solid. Part 2: Dynamic crack represented by the Dugdale model

NASA Technical Reports Server (NTRS)

Wnuk, M. P.; Sih, G. C.

1972-01-01

An extension is proposed of the classical theory of fracture to viscoelastic and elastic-plastic materials in which the plasticity effects are confined to a narrow band encompassing the crack front. It is suggested that the Griffith-Irwin criterion of fracture, which requires that the energy release rate computed for a given boundary value problem equals the critical threshold, ought to be replaced by a differential equation governing the slow growth of a crack prior to the onset of rapid propagation. A new term which enters the equation of motion in the dissipative media is proportional to the energy lost within the end sections of the crack, and thus reflects the extent of inelastic behavior of a solid. A concept of apparent surface energy is introduced to account for the geometry dependent and the rate dependent phenomena which influence toughness of an inelastic solid. Three hypotheses regarding the condition for fracture in the subcritical range of load are compared. These are: (1) constant fracture energy (Cherepanov), (2) constant opening displacement at instability (Morozov) and (3) final stretch criterion (Wnuk).

Fluid dynamics of the unsteady two phase processes leading to DDT in granular solid propellants

NASA Technical Reports Server (NTRS)

Krier, H.; Butler, P. B.; Lembeck, M. F.

1980-01-01

Deflagration to Detonation (DDT) was predicted to occur in porous beds of high-energy solid propellants by solving the unsteady fluid mechanical convective heat transfer from hot gas products, obtained from the rapid burning at high pressures, provides the impetus to develop a narrow combustion zone and a resulting strong shock. A parametric study clearly indicates that DDT occurs only when a combination of the solids loading fraction, the burning rate constants, the propellant chemical energy, and the particle size provide for critical energy and gas release to support a detonation wave. Predictions for the run-up length to detonation as a function of these parameters are presented.

Assessment of dissolved-solids loading to the Colorado River in the Paradox Basin between the Dolores River and Gypsum Canyon, Utah

USGS Publications Warehouse

Shope, Christopher L.; Gerner, Steven J.

2014-01-01

Salinity loads throughout the Colorado River Basin have been a concern over recent decades due to adverse impacts on population, natural resources, and regional economics. With substantial financial resources and various reclamation projects, the salt loading to Lake Powell and associated total dissolved-solids concentrations in the Lower Colorado River Basin have been substantially reduced. The Colorado River between its confluence with the Dolores River and Lake Powell traverses a physiographic area where saline sedimentary formations and evaporite deposits are prevalent. However, the dissolved-solids loading in this area is poorly understood due to the paucity of water-quality data. From 2003 to 2011, the U.S. Geological Survey in cooperation with the U.S. Bureau of Reclamation conducted four synoptic sampling events to quantify the salinity loading throughout the study reach and evaluate the occurrence and impacts of both natural and anthropogenic sources. The results from this study indicate that under late-summer base-flow conditions, dissolved-solids loading in the reach is negligible with the exception of the Green River, and that variations in calculated loads between synoptic sampling events are within measurement and analytical uncertainties. The Green River contributed approximately 22 percent of the Colorado River dissolved-solids load, based on samples collected at the lower end of the study reach. These conclusions are supported by water-quality analyses for chloride and bromide, and the results of analyses for the stable isotopes of oxygen and deuterium. Overall, no significant sources of dissolved-solids loading from tributaries or directly by groundwater discharge, with the exception of the Green River, were identified in the study area.

Solid-loaded flows: applications in technology

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

Molerus, O.

1983-01-01

The evaluation of experiments and the representation of the resulting data by nondimensional groups defined ad hoc largely governs the treatment of problems arising with solid-loaded flows in practice. Without doubt, this is a result of the very complex nature of solid-loaded flows and, consequently, empiricism tends to prevail, more or less. To overcome this situation, two sets of nondimensional groups, which take into consideration the translatory, as well as the rotary, motion of particles suspended in a fluid, are derived from the equations of motion of a solid body. The intuitive meaning of these nondimensional groups arises from theirmore » derivation. With respect to applications in engineering, the influence of the rotary motion of a particle on the motion of its center of gravity can thus be taken into account. As such, a common basis for the representation of the different phenomena observed with solid-loaded flows is established. The application of the above concepts to fluidization and hydraulic and pneumatic conveying proves their usefulness. New insights into well-known facts as well as new results demonstrate that taking the real nature of solid particles (i.e., those of finite dimensions) into consideration will provide a common and profound basis for the representation of different phenomena observed with solid-loaded flows in practice.« less

The effect of transient loading on the performance of a mesophilic anaerobic contact reactor at constant feed strength.

PubMed

Sentürk, Elif; Ince, Mahir; Engin, Guleda Onkal

2012-12-15

Anaerobic contact reactor is a high rate anaerobic process consisting of an agitated reactor and a solids settling tank for recycling. It was proved earlier that this type of reactor design offers highly efficient performance in the conversion of organic matter to biogas. In this study, the effect of transient loading on reactor performance in terms of a number of key intermediates and parameters such as, COD removal, pH and alkalinity change, VFAs, effluent MLSS concentration and biogas efficiency over time was examined. For this purpose, a step increase of organic loading rate from 3.35kg COD/m(3)day to 15.61kg COD/m(3)day was employed. The hydraulic retention time decreased to a value of 8.42h by an increase in the influent flow-rate during the transient loading. It was observed that the mesophilic anaerobic contact reactor (MACR) was quite resistant to large transient shocks. The reactor recovered back to its baseline performance only in 15h after the shock loading was stopped. Hence, it can be concluded that this type of reactor design has a high potential in treating food processing wastewaters with varying flow characteristics. Copyright © 2012 Elsevier B.V. All rights reserved.

Dissolved-solids sources, loads, yields, and concentrations in streams of the conterminous United States

USGS Publications Warehouse

Anning, David W.; Flynn, Marilyn E.

2014-01-01

Results from the trend analysis and from the SPARROW model indicate that, compared to monitoring stations with no trends or decreasing trends, stations with increasing trends are associated with a smaller percentage of the predicted dissolved-solids load originating from geologic sources, and a larger percentage originating from urban lands and road deicers. Conversely, compared to stations with increasing trends or no trends, stations with decreasing trends have a larger percentage of the predicted dissolved-solids load originating from geologic sources and a smaller percentage originating from urban lands and road deicers. Stations with decreasing trends also have larger percentages of predicted dissolved-solids load originating from cultivated lands and pasture lands, compared to stations with increasing trends or no trends.

Development of novel sibutramine base-loaded solid dispersion with gelatin and HPMC: physicochemical characterization and pharmacokinetics in beagle dogs.

PubMed

Lim, Hyun-Tae; Balakrishnan, Prabagar; Oh, Dong Hoon; Joe, Kwan Hyung; Kim, Young Ran; Hwang, Doo Hyung; Lee, Yong-Bok; Yong, Chul Soon; Choi, Han-Gon

2010-09-15

To develop a novel sibutramine base-loaded solid dispersion with enhanced solubility and bioavailability, various solid dispersions were prepared using a spray drying technique with hydrophilic polymers such as gelatin, HPMC and citric acid. Their solubility, thermal characteristics and crystallinity were investigated. The dissolution and pharmacokinetics of the sibutramine base-loaded solid dispersion were then compared with a sibutramine hydrochloride monohydrate-loaded commercial product (Reductil). The solid dispersions prepared with gelatin gave higher drug solubility than those prepared without gelatin, irrespective of the amount of polymer. The sibutramine base-loaded solid dispersions containing hydrophilic polymer and citric acid showed higher drug solubility compared to sibutramine base and sibutramine hydrochloride monohydrate. Among the formulations tested, the solid dispersion composed of sibutramine base/gelatin/HPMC/citric acid at the weight ratio of 1/0.8/0.2/0.5 gave the highest solubility of 5.03+/-0.24 mg/ml. Our DSC and powder X-ray diffraction results showed that the drug was present in an altered amorphous form in this solid dispersion. The difference factor (f(1)) values between solid dispersion and commercial product were 2.82, 6.65 and 6.31 at pH 1.2, 4.0 and 6.8, respectively. Furthermore, they had the similarity factor (f(2)) value of 65.68, 53.43 and 58.97 at pH 1.2, 4.0 and 6.8, respectively. Our results suggested that the solid dispersion and commercial product produced a similar correlation of dissolution profiles at all pH ranges. The AUC, C(max) and T(max) of the parent drug and metabolite I and II from the solid dispersion were not significantly different from those of the commercial product, suggesting that the solid dispersion might be bioequivalent to the commercial product in beagle dogs. Thus, the sibutramine base-loaded solid dispersion prepared with gelatin, HPMC and citric acid is a promising candidate for improving the solubility and bioavailability of the poorly water-soluble sibutramine base. Crown Copyright 2010. Published by Elsevier B.V. All rights reserved.

Extremely fast increase in the organic loading rate during the co-digestion of rapeseed oil and sewage sludge in a CSTR--characterization of granules formed due to CaO addition to maintain process stability.

PubMed

Kasina, M; Kleyböcker, A; Michalik, M; Würdemann, H

2015-01-01

In a co-digestion system running with rapeseed oil and sewage sludge, an extremely fast increase in the organic loading rate was studied to develop a procedure to allow for flexible and demand-driven energy production. The over-acidification of the digestate was successfully prevented by calcium oxide dosage, which resulted in granule formation. Mineralogical analyses revealed that the granules were composed of insoluble salts of long chain fatty acids and calcium and had a porous structure. Long chain fatty acids and calcium formed the outer cover of granules and offered interfaces on the inside thereby enhancing the growth of biofilms. With granule size and age, the pore size increased and indicated degradation of granular interfaces. A stable biogas production up to the organic loading rate of 10.4 kg volatile solids m(-3) d(-1) was achieved although the hydrogen concentration was not favorable for propionic acid degradation. However, at higher organic loading rates, unbalanced granule formation and degradation were observed. Obviously, the adaption time for biofilm growth was too short to maintain the balance, thereby resulting in a low methane yield.

Enhanced bioethanol production by fed-batch simultaneous saccharification and co-fermentation at high solid loading of Fenton reaction and sodium hydroxide sequentially pretreated sugarcane bagasse.

PubMed

Zhang, Teng; Zhu, Ming-Jun

2017-04-01

A study on the fed-batch simultaneous saccharification and co-fermentation (SSCF) of Fenton reaction combined with NaOH pretreated sugarcane bagasse (SCB) at a high solid loading of 10-30% (w/v) was investigated. Enzyme feeding mode, substrate feeding mode and combination of both were compared with the batch mode under respective solid loadings. Ethanol concentrations of above 80g/L were obtained in batch and enzyme feeding modes at a solid loading of 30% (w/v). Enzyme feeding mode was found to increase ethanol productivity and reduce enzyme loading to a value of 1.23g/L/h and 9FPU/g substrate, respectively. The present study provides an economically feasible process for high concentration bioethanol production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Novel dual-reverse thermosensitive solid lipid nanoparticle-loaded hydrogel for rectal administration of flurbiprofen with improved bioavailability and reduced initial burst effect.

PubMed

Din, Fakhar Ud; Mustapha, Omer; Kim, Dong Wuk; Rashid, Rehmana; Park, Jong Hyuck; Choi, Ju Yeon; Ku, Sae Kwang; Yong, Chul Soon; Kim, Jong Oh; Choi, Han-Gon

2015-08-01

The purpose of this study was to develop novel solid lipid nanoparticle (SLN)-loaded dual-reverse thermosensitive hydrogel (DRTH) for rectal administration of flurbiprofen with improved bioavailability and reduced initial burst effect. The flurbiprofen-loaded SLNs were prepared by hot homogenisation technique, after optimising the amounts of lipid mixture (tricaprin and triethanolamine in 8:2 weight ratio), drug and surfactant. The flurbiprofen-loaded thermosensitive SLN composed of drug, lipid mixture and surfactant at a weight ratio of 10/15/1.3 was a solid at room temperature, and changed to liquid form at physiological temperature due to its melting point of about 32°C. This SLN gave the mean particle size of about 190nm and entrapment efficiency of around 90%. The DRTHs were prepared by adding this flurbiprofen-loaded thermosensitive SLN in various poloxamer solutions. Their rheological characterisation, release and stability were investigated while a morphological and pharmacokinetic study was performed after its rectal administration to rats compared with the drug and hydrogel. Poloxamer 188 and SLN decreased the gelation temperature and gelation time, but increased the viscosity at 25°C, gel strength and mucoadhesive force of DRTHs. In particular, the DRTH composed of [SLN/P 407/P 188 (10%/15%/25%)] with the gelation temperature of about 35°C existed as liquid at room temperature, but gelled at 30-36°C, leading to opposite reversible property of SLN. Thus, it was easy to administer rectally, and it gelled rapidly inside the body. This DRTH gave a significantly increased dissolution rate of the drug as compared to the flurbiprofen, but significantly retarded as compared to the hydrogel, including the initial dissolution rate. Moreover, this DRTH gave significantly higher plasma concentration and 7.5-fold AUC values compared to the drug, and lower initial plasma concentration and Cmax value compared to the hydrogel due to reduced initial burst effect. No damage in rectal mucosa was observed after the application of DRTH. Thus, this DRTH system with improved bioavailability and reduced initial burst effect would be recommended as an alternative for the flurbiprofen-loaded rectal pharmaceutical products. Copyright © 2015 Elsevier B.V. All rights reserved.

Evolved strains of Scheffersomyces stipitis achieving high ethanol productivity on acid- and base-pretreated biomass hydrolyzate at high solids loading

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

Slininger, Patricia J.; Shea-Andersh, Maureen A.; Thompson, Stephanie R.

Lignocellulosic biomass is an abundant, renewable feedstock useful for the production of fuel-grade ethanol via the processing steps of pretreatment, enzyme hydrolysis, and microbial fermentation. Traditional industrial yeasts do not ferment xylose and are not able to grow, survive, or ferment in concentrated hydrolyzates that contain enough sugar to support economical ethanol recovery since they are laden with toxic byproducts generated during pretreatment. Repetitive culturing in two types of concentrated hydrolyzates was applied along with ethanol challenged xylose-fed continuous culture to force targeted evolution of the native pentose fermenting yeast Scheffersomyces (Pichia) stipitis strain NRRL Y-7124 maintained in the ARSmore » Culture Collection, Peoria, IL. Isolates collected from various enriched populations were screened and ranked based on relative xylose uptake rate and ethanol yield. Ranking on hydrolyzates with and without nutritional supplementation was used to identify those isolates with best performance across diverse conditions. Robust S. stipitis strains adapted to perform very well in enzyme hydrolyzates of high solids loading ammonia fiber expansion-pretreated corn stover (18% weight per volume solids) and dilute sulfuric acid-pretreated switchgrass (20% w/v solids) were obtained. Improved features include reduced initial lag phase preceding growth, significantly enhanced fermentation rates, improved ethanol tolerance and yield, reduced diauxic lag during glucose-xylose transition, and ability to accumulate >40 g/L ethanol in <167 h when fermenting hydrolyzate at low initial cell density of 0.5 absorbance units and pH 5 to 6.« less

Evolved strains of Scheffersomyces stipitis achieving high ethanol productivity on acid- and base-pretreated biomass hydrolyzate at high solids loading

DOE PAGES

Slininger, Patricia J.; Shea-Andersh, Maureen A.; Thompson, Stephanie R.; ...

2015-04-09

Lignocellulosic biomass is an abundant, renewable feedstock useful for the production of fuel-grade ethanol via the processing steps of pretreatment, enzyme hydrolysis, and microbial fermentation. Traditional industrial yeasts do not ferment xylose and are not able to grow, survive, or ferment in concentrated hydrolyzates that contain enough sugar to support economical ethanol recovery since they are laden with toxic byproducts generated during pretreatment. Repetitive culturing in two types of concentrated hydrolyzates was applied along with ethanol challenged xylose-fed continuous culture to force targeted evolution of the native pentose fermenting yeast Scheffersomyces (Pichia) stipitis strain NRRL Y-7124 maintained in the ARSmore » Culture Collection, Peoria, IL. Isolates collected from various enriched populations were screened and ranked based on relative xylose uptake rate and ethanol yield. Ranking on hydrolyzates with and without nutritional supplementation was used to identify those isolates with best performance across diverse conditions. Robust S. stipitis strains adapted to perform very well in enzyme hydrolyzates of high solids loading ammonia fiber expansion-pretreated corn stover (18% weight per volume solids) and dilute sulfuric acid-pretreated switchgrass (20% w/v solids) were obtained. Improved features include reduced initial lag phase preceding growth, significantly enhanced fermentation rates, improved ethanol tolerance and yield, reduced diauxic lag during glucose-xylose transition, and ability to accumulate >40 g/L ethanol in <167 h when fermenting hydrolyzate at low initial cell density of 0.5 absorbance units and pH 5 to 6.« less

Effect of filter media thickness on the performance of sand drying beds used for faecal sludge management.

PubMed

Manga, M; Evans, B E; Camargo-Valero, M A; Horan, N J

2016-12-01

The effect of sand filter media thickness on the performance of faecal sludge (FS) drying beds was determined in terms of: dewatering time, contaminant load removal efficiency, solids generation rate, nutrient content and helminth eggs viability in the dried sludge. A mixture of ventilated improved pit latrine sludge and septage in the ratio 1:2 was dewatered using three pilot-scale sludge drying beds with sand media thicknesses of 150, 250 and 350 mm. Five dewatering cycles were conducted and monitored for each drying bed. Although the 150 mm filter had the shortest average dewatering time of 3.65 days followed by 250 mm and 350 mm filters with 3.83 and 4.02 days, respectively, there was no significant difference (p > 0.05) attributable to filter media thickness configurations. However, there was a significant difference for the percolate contaminant loads in the removal and recovery efficiency of suspended solids, total solids, total volatile solids, nitrogen species, total phosphorus, chemical oxygen demand, dissolved chemical oxygen demand and biochemical oxygen demand, with the highest removal efficiency for each parameter achieved by the 350 mm filter. There were also significant differences in the nutrient content (NPK) and helminth eggs viability of the solids generated by the tested filters. Filtering media configurations similar to 350 mm have the greatest potential for optimising nutrient recovery from FS.

Effect of Degeneration on Fluid-Solid Interaction within Intervertebral Disk Under Cyclic Loading - A Meta-Model Analysis of Finite Element Simulations.

PubMed

Nikkhoo, Mohammad; Khalaf, Kinda; Kuo, Ya-Wen; Hsu, Yu-Chun; Haghpanahi, Mohammad; Parnianpour, Mohamad; Wang, Jaw-Lin

2015-01-01

The risk of low back pain resulted from cyclic loadings is greater than that resulted from prolonged static postures. Disk degeneration results in degradation of disk solid structures and decrease of water contents, which is caused by activation of matrix digestive enzymes. The mechanical responses resulted from internal solid-fluid interactions of degenerative disks to cyclic loadings are not well studied yet. The fluid-solid interactions in disks can be evaluated by mathematical models, especially the poroelastic finite element (FE) models. We developed a robust disk poroelastic FE model to analyze the effect of degeneration on solid-fluid interactions within disk subjected to cyclic loadings at different loading frequencies. A backward analysis combined with in vitro experiments was used to find the elastic modulus and hydraulic permeability of intact and enzyme-induced degenerated porcine disks. The results showed that the averaged peak-to-peak disk deformations during the in vitro cyclic tests were well fitted with limited FE simulations and a quadratic response surface regression for both disk groups. The results showed that higher loading frequency increased the intradiscal pressure, decreased the total fluid loss, and slightly increased the maximum axial stress within solid matrix. Enzyme-induced degeneration decreased the intradiscal pressure and total fluid loss, and barely changed the maximum axial stress within solid matrix. The increase of intradiscal pressure and total fluid loss with loading frequency was less sensitive after the frequency elevated to 0.1 Hz for the enzyme-induced degenerated disk. Based on this study, it is found that enzyme-induced degeneration decreases energy attenuation capability of disk, but less change the strength of disk.

Hypericin encapsulated in solid lipid nanoparticles: phototoxicity and photodynamic efficiency.

PubMed

Lima, Adriel M; Pizzol, Carine Dal; Monteiro, Fabíola B F; Creczynski-Pasa, Tânia B; Andrade, Gislaine P; Ribeiro, Anderson O; Perussi, Janice R

2013-08-05

The hydrophobicity of some photosensitizers can induce aggregation in biological systems, which consequently reduces photodynamic activity. The conjugation of photosensitizers with nanocarrier systems can potentially be used to overcome this problem. The objective of this study was to prepare and characterise hypericin-loaded solid lipid nanoparticles (Hy-SLN) for use in photodynamic therapy (PDT). SLN were prepared using the ultrasonication technique, and their physicochemical properties were characterised. The mean particle size was found to be 153 nm, with a low polydispersity index of 0.28. One of the major advantages of the SLN formulation is its high entrapment efficiency (EE%). Hy-SLN showed greater than 80% EE and a drug loading capacity of 5.22% (w/w). To determine the photodynamic efficiency of Hy before and after encapsulation in SLN, the rate constants for the photodecomposition of two (1)O2 trapping reagents, DPBF and AU, were determined. These rate constants exhibited an increase of 60% and 50% for each method, respectively, which is most likely due to an increase in the lifetime of the triplet state caused by the increase in solubility. Hy-SLN presented a 30% increase in cell uptake and a correlated improvement of 26% in cytotoxicity. Thus, all these advantages suggest that Hy-loaded SLN has potential for use in PDT. Copyright © 2013 Elsevier B.V. All rights reserved.

Improvements of the cyclone separator performance by down-comer tubes.

PubMed

Ganegama Bogodage, Sakura; Leung, A Y T

2016-07-05

Enhancement of fine particle (PM2.5) separation is important for cyclone separators to reduce any extra purification process required at the outlet. Therefore, the present experimental research was performed to explore the performance of cyclone separators modified with down-comer tubes at solid loading rates from 0 to 8.0 g/m(3) with a 10 m/s inlet velocity. The study proved the effectiveness of down-comer tubes in reducing the particle re-entrainment and increasing the finer separation with acceptable pressure drops, which was pronounced at low solid loading conditions. The experimental results were compared with theories of Smolik and Muschelknautz. Theories were acceptable for certain ranges, and theory breakdown was mainly due to the neglect of particle agglomeration, re-entrainment and the reduction of swirling energy, as well as the increase of wall friction due to presence of particles. Copyright © 2016. Published by Elsevier B.V.

Preparation and evaluation of valsartan by a novel semi-solid self-microemulsifying delivery system using Gelucire 44/14.

PubMed

Zhao, Kun; Yuan, Yue; Wang, Hui; Li, Panpan; Bao, Zhihong; Li, Yue

2016-10-01

The aim of the present study was to develop a novel semi-solid self-microemulsifying drug delivery system (SMEDDS) using Gelucire(®) 44/14 as oil with strong solid character to improve the oral bioavailability of poorly soluble drug valsartan. The solubility of valsartan in various excipients was determined, the pseudo-ternary phase diagram was constructed in order to screen the optimal excipients, and DSC analysis was performed to evaluate the melting point of SMEDDS. The optimal drug-loaded SMEDDS formulation was consisted of 30% Gelucire(®) 44/14 (oil), 40% Solutol(®) HS 15 (surfactant), and 30% Transcutol(®) P (cosurfactant) (w/w) with 80 mg valsartan/g excipients. The average droplet sizes of the optimized blank and drug-loaded SMEDDS formulations were 26.20 ± 1.43 and 33.34 ± 2.15 nm, and the melting points of them were 35.6 and 36.8 °C, respectively. The in vitro dissolution rate of optimal semi-solid SMEDDS was increased compared with commercial capsules, resulting in the 2.72-fold and 2.97-fold enhancement of Cmax and AUC0-t after oral administration in rats, respectively. These results indicated that the novel semi-solid SMEDDS formulation could potentially improve the oral bioavailability of valsartan, and the semi-solid SMEDDS was a desirable system than the traditional liquid SMEDDS because it was convenient for preparation, storage and transportation due to semi-solid state at room temperature and melted state at body temperature.

The construction and operation of a low-cost poultry waste digester.

PubMed

Steinsberger, S C; Shih, J C

1984-05-01

A simple and low-cost poultry waste digester (PWD) was constructed to treat the waste from 4000 caged laying hens on University Research Unit No. 2 at North Carolina State University. The system was built basically of a plastic lining with insulation, a heating system, a hot-water tank, and other metering equipment. It was operated at 50 degrees C and pH 7.5-8.0. The initiation of methane production was achieved using the indigenous microflora in the poultry waste. At an optimal loading rate (7.5 kg volatile solids/m(3) day), the PWD produced biogas (55% methane) at a rate of 4.0 m(3)/m(3) day. The PWD was biologically stable and able to tolerate temporary overloads and shutdowns. A higher loading rate failed to maintain a high gas production rate and caused drops in methane content and pH value. Under optimal conditions, a positive energy balance was demonstrated with a net surplus of 50.6% of the gross energy. For methane production, the PWD system was proved to be technically feasible. The simple design and inexpensive materials used for this model could significantly reduce the cost of digestion compared to more conventional systems. More studies are needed to determine the durability, the required maintenance of the system, and the most economical method of biogas and solid residue utilization.

Land Application of Wastes: An Educational Program. Organic Matter - Module 17, Objectives, and Script.

ERIC Educational Resources Information Center

Clarkson, W. W.; And Others

This module sketches out the impact of sewage organic matter on soils. For convenience, that organic matter is separated into the readily decomposable compounds and the more resistant material (volatile suspended solids, refractory organics, and sludges). The fates of those organics are reviewed along with loading rates and recommended soil…

A High Power Solid State Circuit Breaker for Military Hybrid Electric Vehicle Applications

DTIC Science & Technology

2012-08-01

the SSCB to isolate a fault, breaker opening is latched and can be reset to reclose the breaker via remote logic input. SSCB state and health...rated load current (125 A). Figure 10 shows that after the SSCB detects a fault and opens, it can also be repeatedly reclosed remotely to attempt to

Anaerobic Mesophilic Codigestion of Rice Straw and Chicken Manure: Effects of Organic Loading Rate on Process Stability and Performance.

PubMed

Mei, Zili; Liu, Xiaofeng; Huang, Xianbo; Li, Dong; Yan, Zhiying; Yuan, Yuexiang; Huang, Yajun

2016-07-01

To investigate the effects of organic loading rate (OLR) on performance and stability of mesophilic co-digestion of rice straw (RS) and chicken manure (CM), benchtop experiments (40 L) were carried out at OLRs of 3.0, 3.6, 4.2, 4.8, 6.0, 8.0, and 12.0 kg volatile solid (VS)/(m(3)·day) with volatile solid (VS) ratio of 1:1 (RS/CM) which was based on batch tests. Anaerobic co-digestion was slightly and severely inhibited by the accumulation of ammonia when the digester was overloaded at an OLR of 6 and 12 kg VS/(m(3)·day), respectively. The recommended OLR for co-digestion is 4.8 kg VS/(m(3)·day), which corresponds to average specific biogas production (SBP) of 380 L/kg VS and volumetric biogas production rate (VBPR) of 1.8 m(3)/(m(3)·day). An OLR of 6-8 kg VS/(m(3)·d) with SBP of 360-440 L/kg VS and VBPR of 2.1-3.5 m(3)/(m(3)·day) could be considered, if an Anaerobic digestion (AD) system assisted by in situ removal of ammonia was adopted.

Pretreating wheat straw by phosphoric acid plus hydrogen peroxide for enzymatic saccharification and ethanol production at high solid loading.

PubMed

Qiu, Jingwen; Ma, Lunjie; Shen, Fei; Yang, Gang; Zhang, Yanzong; Deng, Shihuai; Zhang, Jing; Zeng, Yongmei; Hu, Yaodong

2017-08-01

Wheat straw was pretreated by phosphoric acid plus hydrogen peroxide (PHP) for enzymatic hydrolysis and ethanol fermentation at high solid loadings. Results indicated solid loading could reach 20% with 77.4% cellulose-glucose conversion and glucose concentration of 164.9g/L in hydrolysate, it even was promoted to 25% with only 3.4% decrease on cellulose-glucose conversion as the pretreated-wheat straw was dewatered by air-drying. 72.9% cellulose-glucose conversion still was achieved as the minimized enzyme input of 20mg protein/g cellulose was employed for hydrolysis at 20% solid loading. In the corresponding conditions, 100g wheat straw can yield 11.2g ethanol with concentration of 71.2g/L by simultaneous saccharification and fermentation. Thus, PHP-pretreatment benefitted the glucose or ethanol yield at high solid loadings with lower enzyme input. Additionally, decreases on the maximal cellulase adsorption and the direct-orange/direct-blue indicated drying the PHP-pretreated substrates negatively affected the hydrolysis due to the shrinkage of cellulase-size-accommodable pores. Copyright © 2017 Elsevier Ltd. All rights reserved.

Enhanced solubility and bioavailability of sibutramine base by solid dispersion system with aqueous medium.

PubMed

Li, Dong Xun; Jang, Ki-Young; Kang, Wonku; Bae, Kyoungjin; Lee, Mann Hyung; Oh, Yu-Kyoung; Jee, Jun-Pil; Park, Young-Joon; Oh, Dong Hoon; Seo, Youn Gee; Kim, Young Ran; Kim, Jong Oh; Woo, Jong Soo; Yong, Chul Soon; Choi, Han-Gon

2010-01-01

To develop a novel sibutramine base-loaded solid dispersion with improved solubility bioavailability, various solid dispersions were prepared with water, hydroxypropylmethyl cellulose (HPMC), poloxamer and citric acid using spray-drying technique. The effect of HPMC, poloxamer and citric acid on the aqueous solubility of sibutramine was investigated. The physicochemical properties of solid dispersion were investigated using scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and X-ray powder diffraction. The dissolution and pharmacokinetics in rats of solid dispersion were evaluated compared to the sibutramine hydrochloride monohydrate-loaded commercial product (Reductil). The sibutramine base-loaded solid dispersion gave two type forms. Like conventional solid dispersion system, one type appeared as a spherical shape with smooth surface, as the carriers and drug with relatively low melting point were soluble in water and formed it. The other appeared as an irregular form with relatively rough surface. Unlike conventional solid dispersion system, this type changed no crystalline form of drug. Our results suggested that this type was formed by attaching hydrophilic carriers to the surface of drug without crystal change, resulting from changing the hydrophobic drug to hydrophilic form. The sibutramine-loaded solid dispersion at the weight ratio of sibutramine base/HPMC/poloxamer/citric acid of 5/3/3/0.2 gave the maximum drug solubility of about 3 mg/ml. Furthermore, it showed the similar plasma concentration, area under the curve (AUC) and C(max) of parent drug, metabolite I and II to the commercial product, indicating that it might give the similar drug efficacy compared to the sibutramine hydrochloride monohydrate-loaded commercial product in rats. Thus, this solid dispersion system would be useful to deliver poorly water-soluble sibutramine base with enhanced bioavailability.

Saponification pretreatment and solids recirculation as a new anaerobic process for the treatment of slaughterhouse waste.

PubMed

Affes, R; Palatsi, J; Flotats, X; Carrère, H; Steyer, J P; Battimelli, A

2013-03-01

Different configurations of anaerobic process, adapted to the treatment of solid slaughterhouse fatty waste, were proposed and evaluated in this study. The tested configurations are based on the combination of anaerobic digestion with/without waste saponification pretreatment (70 °C during 60 min) and with/without recirculation of the digestate solid fraction (ratio=20% w/w). After an acclimation period of substrate pulses-feeding cycles, the reactors were operated in a semi-continuous feeding mode, increasing organic loading rates along experimental time. The degradation of the raw substrate was shown to be the bottleneck of the whole process, obtaining the best performance and process yields in the reactor equipped with waste pretreatment and solids recirculation. Saponification promoted the emulsification and bioavailability of solid fatty residues, while recirculation of solids minimized the substrate/biomass wash-out and induced microbial adaptation to the treatment of fatty substrates. Copyright © 2013 Elsevier Ltd. All rights reserved.

Rotating belt sieves for primary treatment, chemically enhanced primary treatment and secondary solids separation.

PubMed

Rusten, B; Rathnaweera, S S; Rismyhr, E; Sahu, A K; Ntiako, J

2017-06-01

Fine mesh rotating belt sieves (RBS) offer a very compact solution for removal of particles from wastewater. This paper shows examples from pilot-scale testing of primary treatment, chemically enhanced primary treatment (CEPT) and secondary solids separation of biofilm solids from moving bed biofilm reactors (MBBRs). Primary treatment using a 350 microns belt showed more than 40% removal of total suspended solids (TSS) and 30% removal of chemical oxygen demand (COD) at sieve rates as high as 160 m³/m²-h. Maximum sieve rate tested was 288 m³/m²-h and maximum particle load was 80 kg TSS/m²-h. When the filter mat on the belt increased from 10 to 55 g TSS/m², the removal efficiency for TSS increased from about 35 to 60%. CEPT is a simple and effective way of increasing the removal efficiency of RBS. Adding about 1 mg/L of cationic polymer and about 2 min of flocculation time, the removal of TSS typically increased from 40-50% without polymer to 60-70% with polymer. Using coagulation and flocculation ahead of the RBS, separation of biofilm solids was successful. Removal efficiencies of 90% TSS, 83% total P and 84% total COD were achieved with a 90 microns belt at a sieve rate of 41 m³/m²-h.

Thermo-elastic-plastic analysis for elastic component under high temperature fatigue crack growth rate

NASA Astrophysics Data System (ADS)

Ali, Mohammed Ali Nasser

The research project presents a fundamental understanding of the fatigue crack growth mechanisms of AISI 420 martensitic stainless steel, based on the comparison analysis between the theoretical and numerical modelling, incorporating research findings under isothermal fatigue loading for solid cylindrical specimen and the theoretical modelling with the numerical simulation for tubular specimen when subjected to cyclic mechanical loading superimposed by cyclic thermal shock.The experimental part of this research programme studied the fatigue stress-life data for three types of surface conditions specimen and the isothermal stress-controlled fatigue testing at 300 °C - 600 °C temperature range. It is observed that the highest strength is obtained for the polished specimen, while the machined specimen shows lower strength, and the lowest strength is the notched specimen due to the high effect of the stress concentration. The material behaviour at room and high temperatures shows an initial hardening, followed by slow extension until fully plastic saturation then followed by crack initiation and growth eventually reaching the failure of the specimen, resulting from the dynamic strain ageing occurred from the transformation of austenitic microstructure to martensite and also, the nucleation of precipitation at grain boundaries and the incremental temperature increase the fatigue crack growth rate with stress intensity factor however, the crack growth rate at 600 °C test temperature is less than 500 °C because of the creep-fatigue taking place.The theoretical modelling presents the crack growth analysis and stress and strain intensity factor approaches analysed in two case studies based on the addition of thermo-elastic-plastic stresses to the experimental fatigue applied loading. Case study one estimates the thermal stresses superimposed sinusoidal cyclic mechanical stress results in solid cylinder under isothermal fatigue simulation. Case study two estimates the transient thermal stresses superimposed on cyclic mechanical loading results in hollow cylinder under thermal shock in heating case and down shock cooling case. The combination of stress and strain intensity factor theoretical calculations with the experimental output recorded data shows a similar behaviour with increasing temperature, and there is a fair correlation between the profiles at the beginning and then divergence with increasing the crack length. The transient influence of high temperature in case two, giving a very high thermal shock stress as a heating or cooling effects, shifting up the combined stress, when applied a cyclic mechanical load in fraction of seconds, and the reputations of these shocks, causing a fast failure under high thermal shock stress superimposed with mechanical loading.Finally, the numerical modelling analyses three cases studied were solved due to the types of loading and types of specimen geometry by using finite element models constructed through the ANSYS Workbench version 13.0. The first case is a low cyclic fatigue case for a solid cylinder specimen simulated by applying a cyclic mechanical loading. The second is an isothermal fatigue case for solid cylinder specimen simulated by supplying different constant temperatures on the outer surface with cyclic mechanical loading, where the two cases are similar to the experimental tests and the third case, is a thermo-mechanical fatigue for a hollow cylinder model by simulating a thermal up-shock generated due to transient heating on the outer surface of the model or down shock cooling on the inner surface with the cyclic mechanical loading. The results show a good agreement with the experimental data in terms of alternative stress and life in the first case. In case two results show the strain intensity factor is increases with increasing temperature similar to the theoretical solution due to the influence of the modulus of elasticity and the difference in life estimation with the experimental output record is related to the input data made of theoretical physical properties and the experimental stress-life data.

Enhancement of ethanol production from green liquor-ethanol-pretreated sugarcane bagasse by glucose-xylose cofermentation at high solid loadings with mixed Saccharomyces cerevisiae strains.

PubMed

You, Yanzhi; Li, Pengfei; Lei, Fuhou; Xing, Yang; Jiang, Jianxin

2017-01-01

Efficient cofermentation of glucose and xylose is necessary for economically feasible bioethanol production from lignocellulosic biomass. Here, we demonstrate pretreatment of sugarcane bagasse (SCB) with green liquor (GL) combined with ethanol (GL-Ethanol) by adding different GL amounts. The common Saccharomyces cerevisiae (CSC) and thermophilic S. cerevisiae (TSC) strains were used and different yeast cell mass ratios (CSC to TSC) were compared. The simultaneous saccharification and cofermentation (SSF/SSCF) process was performed by 5-20% (w/v) dry substrate (DS) solid loadings to determine optimal conditions for the co-consumption of glucose and xylose. Compared to previous studies that tested fermentation of glucose using only the CSC, we obtained higher ethanol yield and concentration (92.80% and 23.22 g/L) with 1.5 mL GL/g-DS GL-Ethanol-pretreated SCB at 5% (w/v) solid loading and a CSC-to-TSC yeast cell mass ratio of 1:2 (w/w). Using 10% (w/v) solid loading under the same conditions, the ethanol concentration increased to 42.53 g/L but the ethanol yield decreased to 84.99%. In addition, an increase in the solid loading up to a certain point led to an increase in the ethanol concentration from 1.5 mL GL/g-DS-pretreated SCB. The highest ethanol concentration (68.24 g/L) was obtained with 15% (w/v) solid loading, using a CSC-to-TSC yeast cell mass ratio of 1:3 (w/w). GL-Ethanol pretreatment is a promising pretreatment method for improving both glucan and xylan conversion efficiencies of SCB. There was a competitive relationship between the two yeast strains, and the glucose and xylose utilization ability of the TSC was better than that of the CSC. Ethanol concentration was obviously increased at high solid loading, but the yield decreased as a result of an increase in the viscosity and inhibitor levels in the fermentation system. Finally, the SSCF of GL-Ethanol-pretreated SCB with mixed S. cerevisiae strains increased ethanol concentration and was an effective conversion process for ethanol production at high solid loading.

Loading and release mechanisms of a biocide in polystyrene-block-poly(acrylic acid) block copolymer micelles.

PubMed

Vyhnalkova, Renata; Eisenberg, Adi; van de Ven, Theo G M

2008-07-24

The kinetics of loading of polystyrene197-block-poly(acrylic acid)47 (PS197-b-PAA47) micelles, suspended in water, with thiocyanomethylthiobenzothiazole biocide and its subsequent release were investigated. Loading of the micelles was found to be a two-step process. First, the surface of the PS core of the micelles is saturated with biocide, with a rate determined by the transfer of solid biocide to micelles during transient micelle-biocide contacts. Next, the biocide penetrates as a front into the micelles, lowering the Tg in the process (non-Fickian case II diffusion). The slow rate of release is governed by the height of the energy barrier that a biocide molecule must overcome to pass from PS into water, resulting in a uniform biocide concentration within the micelle, until Tg is increased to the point that diffusion inside the micelles becomes very slow. Maximum loading of biocide into micelles is approximately 30% (w/w) and is achieved in 1 h. From partition experiments, it can be concluded that the biocide has a similar preference for polystyrene as for ethylbenzene over water, implying that the maximum loading is governed by thermodynamics.

Load relaxation of olivine single crystals

NASA Astrophysics Data System (ADS)

Cooper, Reid F.; Stone, Donald S.; Plookphol, Thawatchai

2016-10-01

Single crystals of ferromagnesian olivine (San Carlos, AZ, peridot; Fo88-90) have been deformed in both uniaxial creep and load relaxation under conditions of ambient pressure, T = 1500°C and pO2 = 10-10 atm; creep stresses were in the range 40 ≤ σ1 (MPa) ≤ 220. The crystals were oriented such that the applied stress was parallel to [011]c, which promotes single slip on the slowest slip system in olivine, (010)[001]. The creep rates at steady state match well the results of earlier investigators, as does the stress sensitivity (a power law exponent of n = 3.6). Dislocation microstructures, including spatial distribution of low-angle (subgrain) boundaries, additionally confirm previous investigations. Inverted primary creep (an accelerating strain rate with an increase in stress) was observed. Load relaxation, however, produced a singular response—a single hardness curve—regardless of the magnitude of creep stress or total accumulated strain preceding relaxation. The log stress versus log strain rate data from load-relaxation and creep experiments overlap to within experimental error. The load-relaxation behavior is distinctly different than that described for other crystalline solids, where the flow stress is affected strongly by work hardening such that a family of distinct hardness curves is generated, which are related by a scaling function. The response of olivine for the conditions studied, we argue, indicates flow that is rate limited by dislocation glide, reflecting specifically a high intrinsic lattice resistance (Peierls stress).

Load Relaxation of Olivine Single Crystals

NASA Astrophysics Data System (ADS)

Cooper, R. F.; Stone, D. S.; Plookphol, T.

2016-12-01

Single crystals of ferromagnesian olivine (San Carlos, AZ, peridot; Fo90-92) have been deformed in both uniaxial creep and load relaxation under conditions of ambient pressure, T = 1500ºC and pO2 = 10-10 atm; creep stresses were in the range 40 ≤ σ1 (MPa) ≤ 220. The crystals were oriented such that the applied stress was parallel to [011]c, which promotes single slip on the slowest slip system in olivine, (010)[001]. The creep rates at steady state match well the results of earlier investigators, as does the stress sensitivity (a power-law exponent of n = 3.6). Dislocation microstructures, including spatial distribution of low-angle (subgrain) boundaries, additionally confirm previous investigations. Inverted primary creep (an accelerating strain rate with an increase in stress) was observed. Load-relaxation, however, produced a singular response—a single hardness curve—regardless of the magnitude of creep stress or total accumulated strain preceding relaxation. The log-stress v. log-strain rate data from load-relaxation and creep experiments overlap to within experimental error. The load-relaxation behavior is distinctly different that that described for other crystalline solids, where the flow stress is affected strongly by work hardening such that a family of distinct hardness curves is generated, which are related by a scaling function. The response of olivine for the conditions studied, thus, indicates flow that is rate-limited by dislocation glide, reflecting specifically a high intrinsic lattice resistance (Peierls stress).

Influence of load and sliding velocity on wear resistance of solid-lubricant composites of ultra-high molecular weight polyethylene

NASA Astrophysics Data System (ADS)

Panin, S. V.; Kornienko, L. A.; Buslovich, D. G.; Alexenko, V. O.; Ivanova, L. R.

2017-12-01

To determine the limits of the operation loading intervals appropriate for the use of solid lubricant UHMWPE composites in tribounits for mechanical engineering and medicine, the tribotechnical properties of UHMWPE blends with the optimum solid lubricant filler content (polytetrafluoroethylene, calcium stearate, molybdenum disulfide, colloidal graphite, boron nitride) are studied under dry sliding friction at different velocities (V = 0.3 and 0.5 m/s) and loads (P = 60 and 140 N). It is shown that the wear resistance of solid lubricant UHMWPE composites at moderate sliding velocities (V = 0.3 m/s) and loads (P = 60 N) increases 2-3 times in comparison with pure UHMWPE, while at high load P = 140 N wear resistance of both neat UHMWPE and its composites is reduced almost twice. At high sliding velocities and loads (up to P = 140 N), multiple increasing of the wear of pure UHMWPE and its composites takes place (by the factor of 5 to 10). The operational conditions of UHMWPE composites in tribounits in engineering and medicine are discussed.

Thrust-isolating mounting. [characteristics of support for loads mounted in spacecraft

NASA Technical Reports Server (NTRS)

Wetzler, D. G. (Inventor)

1974-01-01

A supporting frame for a load, such as one or more telescopes, is isolated from all multi-gravitational forces, which will be developed within that load as that load is propelled into space, by using a shroud to fully and solidly hold that load until that load has been propelled into space. Thereafter, that shroud will be jettisoned; and then supports which are on, and which are movable with, that load will have surfaces thereon moved into supporting engagement with complementary surfaces on that supporting frame to enable that supporting frame and those supports to fully and solidly hold that load.

Grassed swales for stormwater pollution control during rain and snowmelt.

PubMed

Bäckström, M

2003-01-01

The retention of suspended solids, particles and heavy metals in different grassed swales during rain events and snowmelt is discussed. The experimental results derived from investigations performed in existing grassed swales in the Luleå region, Northern Sweden. During high pollutant loading rates, grassed swales retain significant amounts of pollutants, mainly due to sedimentation of particulate matter. Low to moderate removal efficiencies could be expected for heavy metals, especially metals in solution (i.e. the dissolved phase). When grassed swales receive urban runoff with low pollutant concentrations, they may release rather than retain pollutants. Swales are important snow deposit areas in the city and particle bound pollutants do to a large extent remain in the swale after snowmelt. However, dissolved pollutants (i.e. dissolved heavy metals) are likely to escape the swale with the melt water. Grassed swales may be regarded as facilities that even out the peaks in pollutant loads without being capable of producing consistent high removal rates. This suggests that swales should be considered as primary treatment devices. Possible design parameters for grassed swales are mean hydraulic detention time, surface loading rate or specific swale area.

Modeling the impact behavior of high strength ceramics. Final report

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

Rajendran, A.M.

1993-12-01

An advanced constitutive model is used to describe the shock and high strain rate behaviors of silicon carbide (SC), boron carbide B4C, and titanium diboride (TiB2) under impact loading conditions. The model's governing equations utilize a set of microphysically-based constitutive relationships to model the deformation and damage processes in a ceramic. The total strain is decomposed into elastic, plastic, and microcracking components. The plastic strain component was calculated using conventional viscoplastic equations. The strain components due to microcracking utilized relationships derived for a penny-shaped crack containing elastic solids. The main features of the model include degradation of strength and stiffnessmore » under both compressive and tensile loading conditions. When loaded above the Hugoniot elastic limit (HEL), the strength is limited by the strain rate dependent strength equation. However, below the HEL, the strength variation with respect to strain rate and pressure is modeled through microcracking relationships assuming no plastic flow. The ceramic model parameters were determined using a set of VISAR data from the plate impact experiments.« less

Effects of temperature and organic loading rate on the performance and microbial community of anaerobic co-digestion of waste activated sludge and food waste.

PubMed

Gou, Chengliu; Yang, Zhaohui; Huang, Jing; Wang, Huiling; Xu, Haiyin; Wang, Like

2014-06-01

Anaerobic co-digestion of waste activated sludge and food waste was investigated semi-continuously using continuously stirred tank reactors. Results showed that the performance of co-digestion system was distinctly influenced by temperature and organic loading rate (OLR) in terms of gas production rate (GPR), methane yield, volatile solids (VS) removal efficiency and the system stability. The highest GPR at 55 °C was 1.6 and 1.3 times higher than that at 35 and 45 °C with the OLR of 1 g VSL(-1)d(-1), and the corresponding average CH₄ yields were 0.40, 0.26 and 0.30 L CH₄ g(-1)VSadded, respectively. The thermophilic system exhibited the best load bearing capacity at extremely high OLR of 7 g VSL(-1)d(-1), while the mesophilic system showed the best process stability at low OLRs (< 5 g VSL(-1)d(-1)). Temperature had a more remarkable effect on the richness and diversity of microbial populations than the OLR. Copyright © 2014 Elsevier Ltd. All rights reserved.

Characterization of dissolved solids in water resources of agricultural lands near Manila, Utah, 2004-05

USGS Publications Warehouse

Gerner, Steven J.; Spangler, L.E.; Kimball, B.A.; Naftz, D.L.

2006-01-01

Agricultural lands near Manila, Utah, have been identified as contributing dissolved solids to Flaming Gorge Reservoir. Concentrations of dissolved solids in water resources of agricultural lands near Manila, Utah, ranged from 35 to 7,410 milligrams per liter. The dissolved-solids load in seeps and drains in the study area that discharge to Flaming Gorge Reservoir ranged from less than 0.1 to 113 tons per day. The most substantial source of dissolved solids discharging from the study area to the reservoir was Birch Spring Draw. The mean daily dissolved-solids load near the mouth of Birch Spring Draw was 65 tons per day.The estimated annual dissolved-solids load imported to the study area by Sheep Creek and Peoples Canals is 1,330 and 13,200 tons, respectively. Daily dissolved-solid loads discharging to the reservoir from the study area, less the amount of dissolved solids imported by canals, for the period July 1, 2004, to June 30, 2005, ranged from 72 to 241 tons per day with a mean of 110 tons per day. The estimated annual dissolved-solids load discharging to the reservoir from the study area, less the amount of dissolved solids imported by canals, for the same period was 40,200 tons. Of this 40,200 tons of dissolved solids, about 9,000 tons may be from a regional source that is not associated with agricultural activities. The salt-loading factor is 3,670 milligrams per liter or about 5.0 tons of dissolved solids per acre-foot of deep percolation in Lucerne Valley and 1,620 milligrams per liter or 2.2 tons per acre-foot in South Valley.The variation of δ87Sr with strontium concentration indicates some general patterns that help to define a conceptual model of the processes affecting the concentration of strontium and the δ87Sr isotopic ratio in area waters. As excess irrigation water percolates through soils derived from Mancos Shale, the δ87Sr isotopic ratio (0.21 to 0.69 permil) approaches one that is typical of deep percolation from irrigation on Mancos Shale. The boron concentration and δ11B value for the water sample from Antelope Wash, being distinctly different from water samples from other sites, is evidence that water in Antelope Wash may contain a substantial component of regional ground-water flow.

Advanced Cooling for High Power Electric Actuators

DTIC Science & Technology

1993-01-01

heat and heat transfer rates. At point B, the fluid temperature reaches the melting temperature of the PCM and it starts to melt , storing energy in the...working fluid through the duty cycle represented by the square wave in the upper half of the figure. Starting at point A, the actuator goes to peak load...form of latent heat. As the solid material melts , the coolant temperature continues to rise, but at a much lower rate, as the heat conducts through the

Failure Criterion For Isotropic Time Dependent Materials Which Accounts for Multi-Axial Loading

NASA Technical Reports Server (NTRS)

Richardson, D. E.; Anderson, G. L.; Macon, D. J.

2003-01-01

The Space Shuttle's Reusable Solid Rocket Motor (RSRM) nozzle program has recently conducted testing to characterize the effects of multi-axial loading, temperature and time on the failure characteristics of TIGA321, EA913NA, EA946 (three filled epoxy adhesives). From the test data a "Multi-Axial, Temperature, and Time Dependent" or MATT failure criterion was developed. It is shown that this criterion simplifies, for constant load and constant load rate conditions, into a form that can be easily used for stress analysis. Failure for TIGA321 and EA913NA are characterized below their glass transition temperature. Failure for EA946 is characterized for conditions that pass through its glass transition. The MATT failure criterion is shown to be accurate for a wide range of conditions for these adhesives.

Differential reinforcement of enzymatic hydrolysis by adding chemicals and accessory proteins to high solid loading substrates with different pretreatments.

PubMed

Du, Jian; Song, Wenxia; Zhang, Xiu; Zhao, Jian; Liu, Guodong; Qu, Yinbo

2018-04-23

High dosage of enzyme is required to achieve effective lignocellulose hydrolysis, especially at high-solid loadings, which is a significant barrier to large-scale bioconversion of lignocellulose. Here, we screened four chemical additives and three accessory proteins for their effects on the enzymatic hydrolysis of various lignocellulosic materials. The effects were found to be highly dependent on the composition and solid loadings of substrates. For xylan-extracted lignin-rich corncob residue, the enhancing effect of PEG 6000 was most pronounced and negligibly affected by solid content, which reduced more than half of enzyme demand at 20% dry matter (DM). Lytic polysaccharide monooxygenase enhanced the hydrolysis of ammonium sulfite wheat straw pulp, and its addition reduced about half of protein demand at the solid loading of 20% DM. Supplementation of the additives in the hydrolysis of pure cellulose and complex lignocellulosic materials revealed that their effects are tightly linked to pretreatment strategies.

Carbothermal shock synthesis of high-entropy-alloy nanoparticles

NASA Astrophysics Data System (ADS)

Yao, Yonggang; Huang, Zhennan; Xie, Pengfei; Lacey, Steven D.; Jacob, Rohit Jiji; Xie, Hua; Chen, Fengjuan; Nie, Anmin; Pu, Tiancheng; Rehwoldt, Miles; Yu, Daiwei; Zachariah, Michael R.; Wang, Chao; Shahbazian-Yassar, Reza; Li, Ju; Hu, Liangbing

2018-03-01

The controllable incorporation of multiple immiscible elements into a single nanoparticle merits untold scientific and technological potential, yet remains a challenge using conventional synthetic techniques. We present a general route for alloying up to eight dissimilar elements into single-phase solid-solution nanoparticles, referred to as high-entropy-alloy nanoparticles (HEA-NPs), by thermally shocking precursor metal salt mixtures loaded onto carbon supports [temperature ~2000 kelvin (K), 55-millisecond duration, rate of ~105 K per second]. We synthesized a wide range of multicomponent nanoparticles with a desired chemistry (composition), size, and phase (solid solution, phase-separated) by controlling the carbothermal shock (CTS) parameters (substrate, temperature, shock duration, and heating/cooling rate). To prove utility, we synthesized quinary HEA-NPs as ammonia oxidation catalysts with ~100% conversion and >99% nitrogen oxide selectivity over prolonged operations.

Implementation and initial test result of a prototype solid state modulator for pulsed magnetron

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

Dake, Vishal; Mangalvedekar, H.A., E-mail: vishaldake90@gmail.com; Tillu, Abhijit

2014-07-01

A solid-state modulator rated for 50 kV, 120A, 4μs and 250 Hz has been designed. The discharging circuit of the modulator is being tested at ∼ 33 kV, 40-80A, at a maximum pulse repetition rate of 30 pps. The paper discusses development and testing of prototype discharging circuit on resistive load and magnetron. The technique used for measurement of pulse transformer leakage inductance, distributed capacitance and stray primary circuit series inductance will also be discussed in detail. It is necessary to have Energy Storage Capacitors with low ESL for these applications (ESL < 40 nH). The method used for evaluatingmore » the ESL of locally available metalized polypropylene capacitors will also be presented. (author)« less

SRM attrition rate study of the aft motor case segments due to water impact cavity collapse loading

NASA Technical Reports Server (NTRS)

Crockett, C. D.

1976-01-01

The attrition assessment of the aft segments of Solid Rocket Motor due to water impact requires the establishment of a correlation between loading occurrences and structural capability. Each discrete load case, as identified by the water impact velocities and angle, varies longitudinally and radially in magnitude and distribution of the external pressure. The distributions are further required to be shifted forward or aft one-fourth the vehicle diameter to assure minimization of the effect of test instrumentation location for the load determinations. The asymmetrical load distributions result in large geometric nonlinearities in structural response. The critical structural response is progressive buckling of the case. Discrete stiffeners have been added to these aft segments to aid in gaining maximum structural capability for minimum weight addition for resisting these loads. This report presents the development of the attrition assessment of the aft segments and includes the rationale for eliminating all assessable conservatisms from this assessment.

High rate psychrophilic anaerobic digestion of high solids (35%) dairy manure in sequence batch reactor.

PubMed

Saady, Noori M Cata; Massé, Daniel I

2015-06-01

Zero liquid discharge is increasingly adopted as an objective for waste treatment process. The objective of this study was to increase the feed total solids (TS) and the organic loading rate (OLR) fed to a novel psychrophilic (20°C) dry anaerobic digestion (PDAD). Duplicate laboratory-scale bioreactors were fed cow feces and wheat straw (35% TS in feed) at OLR of 6.0 g TCOD kg(-1) inoculum d(-1) during long-term operation (147 days consisting of 7 successive cycles). An overall average specific methane yield (SMY) of 151.8±7.9 N L CH4 kg(-1) VS fed with an averaged volatile solids removal of 42.4±4.3% were obtained at a volatile solids-based inoculum-to-substrate ratio (ISR) of 2.13±0.2. The operation was stable as indicated by biogas and VFAs profiles and the results were reproducible in successive cycles; a maximum SMY of 163.3±5.7 N L CH4 kg(-1) VS fed was obtained. Hydrolysis was the reaction limiting step. High rate PDAD of 35% TS dairy manure is possible in sequential batch reactor within 21 days treatment cycle length. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Development of novel ibuprofen-loaded solid dispersion with enhanced bioavailability using cycloamylose.

PubMed

Baek, Hyung Hee; Kim, Dae-Hwan; Kwon, So Young; Rho, Shin-Joung; Kim, Dong-Wuk; Choi, Han-Gon; Kim, Yong-Ro; Yong, Chul Soon

2012-03-01

To develop a novel ibuprofen-loaded solid dispersion with enhanced bioavailability using cycloamylose, it was prepared using spray-drying techniques with cycloamylose at a weight ratio of 1:1. The effect of cycloamylose on aqueous solubility of ibuprofen was investigated. The physicochemical properties of solid dispersions were investigated using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray diffraction. The dissolution and bioavailability in rats were evaluated compared with ibuprofen powder. This ibuprofen-loaded solid dispersion improved about 14-fold drug solubility. Ibuprofen was present in an unchanged crystalline state, and cycloamylose played the simple role of a solubilizing agent in this solid dispersion. Moreover, the dispersion gave 2-fold higher AUC (area under the drug concentration-time curve) value compared with a ibuprofen powder, indicating that it improved the oral bioavailability of ibuprofen in rats. Thus, the solid dispersion may be useful to deliver ibuprofen with enhanced bioavailability without crystalline change.

Optimisation of single-phase dry-thermophilic anaerobic digestion under high organic loading rates of industrial municipal solid waste: population dynamics.

PubMed

Zahedi, S; Sales, D; Romero, L I; Solera, R

2013-10-01

Different high feed organic loading rates (OLRs) (from 5.7 g to 46.0 g TVS/l/d) or hydraulic retention times (HRTs) (from 15 d to 2 d) in single-phase dry-thermophilic anaerobic digestion (AD) of organic fraction municipal solid waste (OFMSW) were investigated. The specific gas production (SGP) values (0.25-0.53 m(3)/kg TVS) and the percentages of Eubacteria, Archaea, H2-utilising methanogens (HUMs) and acetate-utilising methanogens (AUMs) were stable within the ranges 80.2-91.1%, 12.4-18.5%, 4.4-9.8% and 5.5-10.9%, respectively. A HUM/AUM ratio greater than 0.7 seems to be necessary to maintain very low partial pressures of H2 required for dry AD process. Increasing OLR resulted in an increase in all the populations, except for propionate-utilising acetogens (PUAs). Optimal conditions were obtained at 3d HRT (OLR=30.7 g TVS/l/d), which is lower than the doubling time of acetogens and methanogens. The methane production (MP) was clearly higher than those reported in AD of OFMSW. Copyright © 2013 Elsevier Ltd. All rights reserved.

Characterization of suspended solids and total phosphorus loadings from small watersheds in Wisconsin

USGS Publications Warehouse

Danz, Mari E.; Corsi, Steven R.; Graczyk, David J.; Bannerman, Roger T.

2010-01-01

Knowledge of the daily, monthly, and yearly distribution of contaminant loadings and streamflow can be critical for the successful implementation and evaluation of water-quality management practices. Loading data for solids (suspended sediment and total suspended solids) and total phosphorus and streamflow data for 23 watersheds were summarized for four ecoregions of Wisconsin: the Driftless Area Ecoregion, the Northern Lakes and Forests Ecoregion, the North Central Hardwoods Ecoregion, and the Southeastern Wisconsin Till Plains Ecoregion. The Northern Lakes and Forests and the North Central Hardwoods Ecoregions were combined into one region for analysis due to a lack of sufficient data in each region. Urban watersheds, all located in the Southeastern Wisconsin Till Plains, were analyzed separately from rural watersheds as the Rural Southeastern Wisconsin Till Plains region and the Urban Southeastern Wisconsin Till Plains region. Results provide information on the distribution of loadings and streamflow between base flow and stormflow, the timing of loadings and streamflow throughout the year, and information regarding the number of days in which the majority of the annual loading is transported. The average contribution to annual solids loading from stormflow periods for the Driftless Area Ecoregion was 84 percent, the Northern Lakes and Forests/North Central Hardwoods region was 71 percent, the Rural Southeastern Wisconsin Till Plains region was 70 percent, and the Urban Southeastern Wisconsin Till Plains region was 90 percent. The average contributions to annual total phosphorus loading from stormflow periods were 72, 49, 61, and 76 percent for each of the respective regions. The average contributions to annual streamflow from stormflow periods are 20, 23, 31, and 50 percent for each of the respective regions. In all regions, the most substantial loading contributions for solids were in the late winter (February through March), spring (April through May), and early summer (June through July), with fall (October through November) and early winter (December through January) contributing the smallest loadings. The Northern Lakes and Forests/North Central Hardwoods region had some substantial loading in September. There was a similar pattern for total phosphorus loading in all regions, with the pattern somewhat less pronounced in urban watersheds. As with the loading results, average monthly streamflow values were greatest in late winter, spring, and early summer, with the lowest values typically in fall and early winter. Loading contributions were greater from stormflow than from base flow in all instances, except total phosphorus in the Northern Lakes and Forests/North Central Hardwoods region, which had equal or greater base-flow contribution for several months. Base flow constituted a greater percentage of the total streamflow than stormflow in all rural watersheds for all regions. Only a few storms each year dominated the annual loading totals for solids and total phosphorus. When daily loading values were ranked for the year, all regions reached 50 percent of the annual solids loading in the 5 highest loading days and nearly 50 percent of the annual total phosphorus loading in the 14 highest loading days.

Comparison of HPMC based polymers performance as carriers for manufacture of solid dispersions using the melt extruder.

PubMed

Ghosh, Indrajit; Snyder, Jennifer; Vippagunta, Radha; Alvine, Marilyn; Vakil, Ronak; Tong, Wei-Qin; Vippagunta, Sudha

2011-10-31

Preparation of amorphous solid dispersions using hot-melt extrusion process for poorly water soluble compounds which degrade on melting remains a challenge due to exposure to high temperatures. The aim of this study was to develop a physically and chemically stable amorphous solid dispersion of a poorly water-soluble compound, NVS981, which is highly thermal sensitive and degrades upon melting at 165 °C. Hydroxypropyl Methyl Cellulose (HPMC) based polymers; HPMC 3cps, HPMC phthalate (HPMCP) and HPMC acetyl succinate (HPMCAS) were selected as carriers to prepare solid dispersions using hot melt extrusion because of their relatively low glass transition temperatures. The solid dispersions were compared for their ease of manufacturing, physical stability such as recrystallization potential, phase separation, molecular mobility and enhancement of drug dissolution. Two different drug loads of 20 and 50% (w/w) were studied in each polymer system. It was interesting to note that solid dispersions with 50% (w/w) drug load were easier to process in the melt extruder compared to 20% (w/w) drug load in all three carriers, which was attributed to the plasticizing behavior of the drug substance. Upon storage at accelerated stability conditions, no phase separation was observed in HPMC 3cps and HPMCAS solid dispersions at the lower and higher drug load, whereas for HPMCP, phase separation was observed at higher drug load after 3 months. The pharmaceutical performance of these solid dispersions was evaluated by studying drug dissolution in pH 6.8 phosphate buffer. Drug release from solid dispersion prepared from polymers used for enteric coating, i.e. HPMCP and HPMCAS was faster compared with the water soluble polymer HPMC 3cps. In conclusion, of the 3 polymers studied for preparing solid dispersions of thermally sensitive compound using hot melt extrusion, HPMCAS was found to be the most promising as it was easily processible and provided stable solid dispersions with enhanced dissolution. Copyright © 2011 Elsevier B.V. All rights reserved.

The impact of particle size and initial solid loading on thermochemical pretreatment of wheat straw for improving sugar recovery.

PubMed

Rojas-Rejón, Oscar A; Sánchez, Arturo

2014-07-01

This work studies the effect of initial solid load (4-32 %; w/v, DS) and particle size (0.41-50 mm) on monosaccharide yield of wheat straw subjected to dilute H(2)SO(4) (0.75 %, v/v) pretreatment and enzymatic saccharification. Response surface methodology (RSM) based on a full factorial design (FFD) was used for the statistical analysis of pretreatment and enzymatic hydrolysis. The highest xylose yield obtained during pretreatment (ca. 86 %; of theoretical) was achieved at 4 % (w/v, DS) and 25 mm. The solid fraction obtained from the first set of experiments was subjected to enzymatic hydrolysis at constant enzyme dosage (17 FPU/g); statistical analysis revealed that glucose yield was favored with solids pretreated at low initial solid loads and small particle sizes. Dynamic experiments showed that glucose yield did not increase after 48 h of enzymatic hydrolysis. Once established pretreatment conditions, experiments were carried out with several initial solid loading (4-24 %; w/v, DS) and enzyme dosages (5-50 FPU/g). Two straw sizes (0.41 and 50 mm) were used for verification purposes. The highest glucose yield (ca. 55 %; of theoretical) was achieved at 4 % (w/v, DS), 0.41 mm and 50 FPU/g. Statistical analysis of experiments showed that at low enzyme dosage, particle size had a remarkable effect over glucose yield and initial solid load was the main factor for glucose yield.

Analysis of the Sediment Hydrograph of the alluvial deltas in the Apalachicola River, Florida

NASA Astrophysics Data System (ADS)

Daranpob, A.; Hagen, S.; Passeri, D.; Smar, D. E.

2011-12-01

Channel and alluvial characteristics in lowlands are the products of boundary conditions and driving forces. The boundary conditions normally include materials and land cover types, such as soil type and vegetation cover. General driving forces include discharge rate, sediment loadings, tides and waves. Deltas built up of river-transported sediment occur in depositional zones of the river mouth in flat terrains and slow currents. Total sediment load depends on two major abilities of the river, the river shear stress and capacity. The shear stress determines transport of a given sediment grain size, normally expressed as tractive force. The river capacity determines the total load or quantity of total sediments transported across a section of the river, generally expressed as the sediment loading rate. The shear stress and sediment loading rate are relatively easy to measure in the headwater and transfer zones where streams form a v-shape valley and the river begins to form defined banks compared to the deposition zone where rivers broaden across lower elevation landscapes creating alluvial forms such as deltas. Determinations of deposition and re-suspension of sediment in fluvial systems are complicated due to exerting tidal, wind, and wave forces. Cyclic forces of tides and waves repeatedly change the sediment transport and deposition rate spatially and temporally in alluvial fans. However, the influence decreases with water depth. Understanding the transport, deposition, and re-suspension of sediments in the fluvial zone would provide a better understanding of the morphology of landscape in lowland estuaries such as the Apalachicola Bay and its estuary systems. The Apalachicola River system is located in the Florida Panhandle. Shelf sedimentation process is not a strong influence in this region because it is protected by barrier islands from direct ocean forces of the Gulf of Mexico. This research explores the characteristic of suspended sediment loadings in fluvial zones of the Apalachicola River and its distributaries through field investigation and laboratory analysis of a series of total suspended solid (TSS) samples. Time-series TSS samples are collected at the alluvial zone. TSS and particle-size distribution analyses are performed to determine the TSS hydrograph and particle-size distribution of suspended solids. Relationships between the TSS hydrograph, discharge hydrograph, and tidal data provide a better understanding of the deposition and re-suspension of the fluvial system in the region. Total suspended particle-size distribution data are used to determine the deposition rate or diminishing rate of alluvial landform in the estuarine system. This dataset and analysis provide excellent information for future modeling work and wetland morphologic studies in the Apalachicola River and similar systems.

Optimization of alkaline sulfite pretreatment and comparative study with sodium hydroxide pretreatment for improving enzymatic digestibility of corn stover.

PubMed

Liu, Huan; Pang, Bo; Wang, Haisong; Li, Haiming; Lu, Jie; Niu, Meihong

2015-04-01

In this study, alkaline sulfite pretreatment of corn stover was optimized. The influences of pretreatments on solid yield, delignification, and carbohydrate recovery under different pretreatment conditions and subsequent enzymatic hydrolysis were investigated. The effect of pretreatment was evaluated by enzymatic hydrolysis efficiency and the total sugar yield. The optimum pretreatment conditions were obtained, as follows: the total titratable alkali (TTA) of 12%, liquid/solid ratio of 6:1, temperature of 140 °C, and holding time of 20 min. Under those conditions, the solid yield was 55.24%, and the removal of lignin was 82.68%. Enzymatic hydrolysis rates of glucan and xylan for pretreated corn stover were 85.38% and 70.36%, and the total sugar yield was 74.73% at cellulase loading of 20 FPU/g and β-glucosidase loading of 10 IU/g for 48 h. Compared with sodium hydroxide pretreatment with the same amount of total titratable alkali, the total sugar yield was raised by about 10.43%. Additionally, the corn stover pretreated under the optimum pretreatment conditions was beaten by PFI at 1500 revolutions. After beating, enzymatic hydrolysis rates of glucan and xylan were 89.74% and 74.06%, and the total sugar yield was 78.58% at the same enzymatic hydrolysis conditions. Compared with 1500 rpm of PFI beating after sodium pretreatment with the same amount of total titratable alkali, the total sugar yield was raised by about 14.05%.

Architecture, component, and microbiome of biofilm involved in the fouling of membrane bioreactors.

PubMed

Inaba, Tomohiro; Hori, Tomoyuki; Aizawa, Hidenobu; Ogata, Atsushi; Habe, Hiroshi

2017-01-01

Biofilm formation on the filtration membrane and the subsequent clogging of membrane pores (called biofouling) is one of the most persistent problems in membrane bioreactors for wastewater treatment and reclamation. Here, we investigated the structure and microbiome of fouling-related biofilms in the membrane bioreactor using non-destructive confocal reflection microscopy and high-throughput Illumina sequencing of 16S rRNA genes. Direct confocal reflection microscopy indicated that the thin biofilms were formed and maintained regardless of the increasing transmembrane pressure, which is a common indicator of membrane fouling, at low organic-loading rates. Their solid components were primarily extracellular polysaccharides and microbial cells. In contrast, high organic-loading rates resulted in a rapid increase in the transmembrane pressure and the development of the thick biofilms mainly composed of extracellular lipids. High-throughput sequencing revealed that the biofilm microbiomes, including major and minor microorganisms, substantially changed in response to the organic-loading rates and biofilm development. These results demonstrated for the first time that the architectures, chemical components, and microbiomes of the biofilms on fouled membranes were tightly associated with one another and differed considerably depending on the organic-loading conditions in the membrane bioreactor, emphasizing the significance of alternative indicators other than the transmembrane pressure for membrane biofouling.

Loading-rate-independent delay of catastrophic avalanches in a bulk metallic glass

DOE PAGES

Chen, S. H.; Chan, K. C.; Wang, G.; ...

2016-02-25

The plastic flow of bulk metallic glasses (BMGs) is characterized by intermittent bursts of avalanches, and this trend results in disastrous failures of BMGs. In the present work, a double-side-notched BMG specimen is designed, which exhibits chaotic plastic flows consisting of several catastrophic avalanches under the applied loading. The disastrous shear avalanches have, then, been delayed by forming a stable plastic-flow stage in the specimens with tailored distances between the bottoms of the notches, where the distribution of a complex stress field is acquired. Differing from the conventional compressive testing results, such a delaying process is independent of loading rate.more » The statistical analysis shows that in the specimens with delayed catastrophic failures, the plastic flow can evolve to a critical dynamics, making the catastrophic failure more predictable than the ones with chaotic plastic flows. Lastly, the findings are of significance in understanding the plastic-flow mechanisms in BMGs and controlling the avalanches in relating solids.« less

Performance of anaerobic fluidized membrane bioreactors using effluents of microbial fuel cells treating domestic wastewater.

PubMed

Kim, Kyoung-Yeol; Yang, Wulin; Ye, Yaoli; LaBarge, Nicole; Logan, Bruce E

2016-05-01

Anaerobic fluidized membrane bioreactors (AFMBRs) have been mainly developed as a post-treatment process to produce high quality effluent with very low energy consumption. The performance of an AFMBR was examined using the effluent from a microbial fuel cell (MFC) treating domestic wastewater, as a function of AFMBR hydraulic retention times (HRTs) and organic matter loading rates. The MFC-AFMBR achieved 89 ± 3% removal of the chemical oxygen demand (COD), with an effluent of 36 ± 6 mg-COD/L over 112 days operation. The AFMBR had very stable operation, with no significant changes in COD removal efficiencies, for HRTs ranging from 1.2 to 3.8h, although the effluent COD concentration increased with organic loading. Transmembrane pressure (TMP) was low, and could be maintained below 0.12 bar through solids removal. This study proved that the AFMBR could be operated with a short HRT but a low COD loading rate was required to achieve low effluent COD. Copyright © 2016 Elsevier Ltd. All rights reserved.

Panel Stiffener Debonding Analysis using a Shell/3D Modeling Technique

NASA Technical Reports Server (NTRS)

Krueger, Ronald; Ratcliffe, James G.; Minguet, Pierre J.

2008-01-01

A shear loaded, stringer reinforced composite panel is analyzed to evaluate the fidelity of computational fracture mechanics analyses of complex structures. Shear loading causes the panel to buckle. The resulting out -of-plane deformations initiate skin/stringer separation at the location of an embedded defect. The panel and surrounding load fixture were modeled with shell elements. A small section of the stringer foot, web and noodle as well as the panel skin near the delamination front were modeled with a local 3D solid model. Across the width of the stringer fo to, the mixed-mode strain energy release rates were calculated using the virtual crack closure technique. A failure index was calculated by correlating the results with a mixed-mode failure criterion of the graphite/epoxy material. The objective was to study the effect of the fidelity of the local 3D finite element model on the computed mixed-mode strain energy release rates and the failure index.

Panel-Stiffener Debonding and Analysis Using a Shell/3D Modeling Technique

NASA Technical Reports Server (NTRS)

Krueger, Ronald; Ratcliffe, James G.; Minguet, Pierre J.

2007-01-01

A shear loaded, stringer reinforced composite panel is analyzed to evaluate the fidelity of computational fracture mechanics analyses of complex structures. Shear loading causes the panel to buckle. The resulting out-of-plane deformations initiate skin/stringer separation at the location of an embedded defect. The panel and surrounding load fixture were modeled with shell elements. A small section of the stringer foot, web and noodle as well as the panel skin near the delamination front were modeled with a local 3D solid model. Across the width of the stringer foot, the mixed-mode strain energy release rates were calculated using the virtual crack closure technique. A failure index was calculated by correlating the results with a mixed-mode failure criterion of the graphite/epoxy material. The objective was to study the effect of the fidelity of the local 3D finite element model on the computed mixed-mode strain energy release rates and the failure index.

Fumaric Acid Production from Alkali-Pretreated Corncob by Fed-Batch Simultaneous Saccharification and Fermentation Combined with Separated Hydrolysis and Fermentation at High Solids Loading.

PubMed

Li, Xin; Zhou, Jin; Ouyang, Shuiping; Ouyang, Jia; Yong, Qiang

2017-02-01

Production of fumaric acid from alkali-pretreated corncob (APC) at high solids loading was investigated using a combination of separated hydrolysis and fermentation (SHF) and fed-batch simultaneous saccharification and fermentation (SSF) by Rhizopus oryzae. Four different fermentation modes were tested to maximize fumaric acid concentration at high solids loading. The highest concentration of 41.32 g/L fumaric acid was obtained from 20 % (w/v) APC at 38 °C in the combined SHF and fed-batch SSF process, compared with 19.13 g/L fumaric acid in batch SSF alone. The results indicated that a combination of SHF and fed-batch SSF significantly improved production of fumaric acid from lignocellulose by R. oryzae than that achieved with batch SSF at high solids loading.

Preparation of resveratrol-loaded nanoporous silica materials with different structures

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

Popova, Margarita, E-mail: mpopova@orgchem.bas.bg; Szegedi, Agnes; Mavrodinova, Vesselina

2014-11-15

Solid, nanoporous silica-based spherical mesoporous MCM-41 and KIL-2 with interparticle mesoporosity as well as nanosized zeolite BEA materials differing in morphology and pore size distribution, were used as carriers for the preparation of resveratrol-loaded delivery systems. Two preparation methods have been applied: (i) loading by mixing of resveratrol and mesoporous carrier in solid state and (ii) deposition in ethanol solution. The parent and the resveratrol loaded carriers were characterized by XRD, TEM, N2 physisorption, thermal analysis, and FT-IR spectroscopy. The influence of the support structure on the adsorption capacity and the release kinetics of this poorly soluble compound were investigated.more » Our results indicated that the chosen nanoporous silica supports are suitable for stabilization of trans-resveratrol and reveal controlled release and ability to protect the supported compound against degradation regardless of loading method. The solid-state dry mixing appears very effective for preparation of drug formulations composed of poorly soluble compound. - Graphical abstract: trans-Resveratrol was stabilized in the pores of BEA zeolite, MCM-41and KIL2 mesoporous silicas. - Highlights: • BEA, KIL-2 and MCM-41 materials were used as carriers for resveratrol loading. • Resveratrol encapsulation in ethanol solution and solid state procedure were applied. • The solid-state preparation appears very effective for stabilization of trans-resveratrol.« less

Flow Strength of Shocked Aluminum in the Solid-Liquid Mixed Phase Region

NASA Astrophysics Data System (ADS)

Reinhart, William

2011-06-01

Shock waves have been used to determine material properties under high shock stresses and very-high loading rates. The determination of mechanical properties such as compressive strength under shock compression has proven to be difficult and estimates of strength have been limited to approximately 100 GPa or less in aluminum. The term ``strength'' has been used in different ways. For a Von-Mises solid, the yield strength is equal to twice the shear strength of the material and represents the maximum shear stress that can be supported before yield. Many of these concepts have been applied to materials that undergo high strain-rate dynamic deformation, as in uni-axial strain shock experiments. In shock experiments, it has been observed that the shear stress in the shocked state is not equal to the shear strength, as evidenced by elastic recompressions in reshock experiments. This has led to an assumption that there is a yield surface with maximum (loading)and minimum (unloading), shear strength yet the actual shear stress lies somewhere between these values. This work provides the first simultaneous measurements of unloading velocity and flow strength for transition of solid aluminum to the liquid phase. The investigation describes the flow strength observed in 1100 (pure), 6061-T6, and 2024 aluminum in the solid-liquid mixed phase region. Reloading and unloading techniques were utilized to provide independent data on the two unknowns (τc and τo) , so that the actual critical shear strength and the shear stress at the shock state could be estimated. Three different observations indicate a change in material response for stresses of 100 to 160 GPa; 1) release wave speed (reloading where applicable) measurements, 2) yield strength measurements, and 3) estimates of Poisson's ratio, all of which provide information on the melt process including internal consistency and/or non-equilibrium and rate-dependent melt behavior. The study investigates the strength properties in the solid region and as the material transverses the solid-mixed-liquid regime. Differences observed appear to be the product of alloying and/or microstructural composition of the aluminum. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

Approximate analytical solution for induction heating of solid cylinders

DOE PAGES

Jankowski, Todd Andrew; Pawley, Norma Helen; Gonzales, Lindsey Michal; ...

2015-10-20

An approximate solution to the mathematical model for induction heating of a solid cylinder in a cylindrical induction coil is presented here. The coupled multiphysics model includes equations describing the electromagnetic field in the heated object, a heat transfer simulation to determine temperature of the heated object, and an AC circuit simulation of the induction heating power supply. A multiple-scale perturbation method is used to solve the multiphysics model. The approximate analytical solution yields simple closed-form expressions for the electromagnetic field and heat generation rate in the solid cylinder, for the equivalent impedance of the associated tank circuit, and formore » the frequency response of a variable frequency power supply driving the tank circuit. The solution developed here is validated by comparing predicted power supply frequency to both experimental measurements and calculated values from finite element analysis for heating of graphite cylinders in an induction furnace. The simple expressions from the analytical solution clearly show the functional dependence of the power supply frequency on the material properties of the load and the geometrical characteristics of the furnace installation. In conclusion, the expressions developed here provide physical insight into observations made during load signature analysis of induction heating.« less

Solid-State Kinetic Investigations of Nonisothermal Reduction of Iron Species Supported on SBA-15

PubMed Central

2017-01-01

Iron oxide catalysts supported on nanostructured silica SBA-15 were synthesized with various iron loadings using two different precursors. Structural characterization of the as-prepared FexOy/SBA-15 samples was performed by nitrogen physisorption, X-ray diffraction, DR-UV-Vis spectroscopy, and Mössbauer spectroscopy. An increasing size of the resulting iron species correlated with an increasing iron loading. Significantly smaller iron species were obtained from (Fe(III), NH4)-citrate precursors compared to Fe(III)-nitrate precursors. Moreover, smaller iron species resulted in a smoother surface of the support material. Temperature-programmed reduction (TPR) of the FexOy/SBA-15 samples with H2 revealed better reducibility of the samples originating from Fe(III)-nitrate precursors. Varying the iron loading led to a change in reduction mechanism. TPR traces were analyzed by model-independent Kissinger method, Ozawa, Flynn, and Wall (OFW) method, and model-dependent Coats-Redfern method. JMAK kinetic analysis afforded a one-dimensional reduction process for the FexOy/SBA-15 samples. The Kissinger method yielded the lowest apparent activation energy for the lowest loaded citrate sample (Ea ≈ 39 kJ/mol). Conversely, the lowest loaded nitrate sample possessed the highest apparent activation energy (Ea ≈ 88 kJ/mol). For samples obtained from Fe(III)-nitrate precursors, Ea decreased with increasing iron loading. Apparent activation energies from model-independent analysis methods agreed well with those from model-dependent methods. Nucleation as rate-determining step in the reduction of the iron oxide species was consistent with the Mampel solid-state reaction model. PMID:29230346

Microbial community adaptation influences long-chain fatty acid conversion during anaerobic codigestion of fats, oils, and grease with municipal sludge.

PubMed

Ziels, Ryan M; Karlsson, Anna; Beck, David A C; Ejlertsson, Jörgen; Yekta, Sepehr Shakeri; Bjorn, Annika; Stensel, H David; Svensson, Bo H

2016-10-15

Codigesting fats, oils, and greases with municipal wastewater sludge can greatly improve biomethane recovery at wastewater treatment facilities. Process loading rates of fats, oils, and greases have been previously tested with little knowledge of the digester microbial community structure, and high transient fat loadings have led to long chain fatty acid (LCFA) accumulation and digester upsets. This study utilized recently-developed quantitative PCR assays for syntrophic LCFA-degrading bacteria along with 16S amplicon sequencing to relate changes in microbial community structure to LCFA accumulation during transient loading increases to an anaerobic codigester receiving waste restaurant oil and municipal wastewater sludge. The 16S rRNA gene concentration of the syntrophic β-oxidizing genus Syntrophomonas increased to ∼15% of the Bacteria community in the codigester, but stayed below 3% in the control digester that was fed only wastewater sludge. Methanosaeta and Methanospirillum were the dominant methanogenic genera enriched in the codigester, and together comprised over 80% of the Archaea community by the end of the experimental period. Constrained ordination showed that changes in the codigester Bacteria and Archaea community structures were related to measures of digester performance. Notably, the effluent LCFA concentration in the codigester was positively correlated to the specific loading rate of waste oil normalized to the Syntrophomonas 16S rRNA concentration. Specific loading rates of 0-1.5 × 10(-12) g VS oil/16S gene copies-day resulted in LCFA concentrations below 30 mg/g TS, whereas LCFA accumulated up to 104 mg/g TS at higher transient loading rates. Based on the community-dependent loading limitations found, enhanced biomethane production from high loadings of fats, oils and greases can be achieved by promoting a higher biomass of slow-growing syntrophic consortia, such as with longer digester solids retention times. This work also demonstrates the potential for controlling the loading rate of fats, oils, and greases based on the analysis of the codigester community structure, such as with quantitative PCR measurements of syntrophic LCFA-degrading bacteria abundance. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evaluation of different types of anaerobic seed sludge for the high rate anaerobic digestion of pig slurry in UASB reactors.

PubMed

Rico, Carlos; Montes, Jesús A; Rico, José Luis

2017-08-01

Three different types of anaerobic sludge (granular, thickened digestate and anaerobic sewage) were evaluated as seed inoculum sources for the high rate anaerobic digestion of pig slurry in UASB reactors. Granular sludge performance was optimal, allowing a high efficiency process yielding a volumetric methane production rate of 4.1LCH 4 L -1 d -1 at 1.5days HRT (0.248LCH 4 g -1 COD) at an organic loading rate of 16.4gCODL -1 d -1 . The thickened digestate sludge experimented flotation problems, thus resulting inappropriate for the UASB process. The anaerobic sewage sludge reactor experimented biomass wash-out, but allowed high process efficiency operation at 3days HRT, yielding a volumetric methane production rate of 1.7LCH 4 L -1 d -1 (0.236LCH 4 g -1 COD) at an organic loading rate of 7.2gCODL -1 d -1 . To guarantee the success of the UASB process, the settleable solids of the slurry must be previously removed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Experimental Studies of Adhesion of a Highly Swollen Gel

NASA Astrophysics Data System (ADS)

Cole, Phillip; Emerson, John

2003-03-01

A fracture mechanics methodology based on the Johnson-Kendall-Roberts (JKR) theory is used to quantify the self-adhesion of a highly swollen gel. The solid phase of the gel is a cross-linked polybutadiene and the liquid phase is dibutylphthlate (maximum 60% by weight). In these experiments two nearly identical gel lenses are brought into contact. Bonding and separation of contact is analyzed in terms of the modified JKR theory of Shull [1]. Simultaneous measurements of the applied load, the load point displacement and the contact radius between the lenses allow us to determine the elastic modulus of the gel and the energy release rate. It also allows us to determine whether the observed hysteresis is primarily due to surface dissipation or due to bulk viscoelasticity. The energy release rate is found to be approximately constant during the bonding phase of the experiment. During the debonding phase, the energy release rate increases with the crack velocity or the receding rate of contact radius. Self-adhesion is quantified in the debonding phase through the relationship between the energy release rate and the crack growth rate. The energy release rate during the bonding phase is compared to the surface tension of the liquid and the solid. We also study the effect of liquid phase on the self-adhesion by varying the amount of liquid from zero percent to the maximum of sixty percent. [1] Shull, K. R. Materials Science and Engineering R-Reports, 36 (2002) 1-45. This work was performed at Sandia National Laboratories, supported by the United States Department of Energy under contract number DE-AC04-94AL85000.

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

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

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

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

Metal-organic framework MIL-101 as sorbent based on double-pumps controlled on-line solid-phase extraction coupled with high-performance liquid chromatography for the determination of flavonoids in environmental water samples.

PubMed

Liu, Yue; Hu, Jia; Li, Yan; Li, Xiao-Shuang; Wang, Zhong-Liang

2016-10-01

A novel method with high sensitivity for the rapid determination of chrysin, apigenin and luteolin in environment water samples was developed by double-pumps controlled on-line solid-phase extraction (SPE) coupled with high-performance liquid chromatography (HPLC). In the developed technique, metal organic framework MIL-101 was synthesized and applied as a sorbent for SPE. The as-synthesized MIL-101 was characterized by scanning electron microscope, X-ray diffraction spectrometry, thermal gravimetric analysis and micropore physisorption analysis. The MIL-101 behaved as a fast kinetics in the adsorption of chrysin, apigenin and luteolin. On-line SPE of chrysin, apigenin and luteolin was processed by loading a sample solution at a flow rate of 1.0 mL/min for 10 min. The extracted analytes were subsequently eluted into a ZORBAX Bonus-RP analytical column (25 cm long × 4.6 mm i.d.) for HPLC separation under isocratic condition with a mobile phase (MeOH: ACN: 0.02 M H 3 PO 4 = 35:35:30) at a flow rate of 1.0 mL/min. Experimental conditions, including ionic strength, sample pH, sample loading rates, sample loading time and desorption analytes time, were further optimized to obtain efficient preconcentration and high-precision determination of the analytes mentioned above. The method achieved the merits of simplicity, rapidity, sensitivity, wide linear range and high sample throughput. The possible mechanism for the adsorption of flavonoids on MIL-101 was proposed. The developed method has been applied to determine trace chrysin, apigenin and luteolin in a variety of environmental water samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High Mass Loading MnO2 with Hierarchical Nanostructures for Supercapacitors.

PubMed

Huang, Zi-Hang; Song, Yu; Feng, Dong-Yang; Sun, Zhen; Sun, Xiaoqi; Liu, Xiao-Xia

2018-04-24

Metal oxides have attracted renewed interest as promising electrode materials for high energy density supercapacitors. However, the electrochemical performance of metal oxide materials deteriorates significantly with the increase of mass loading due to their moderate electronic and ionic conductivities. This limits their practical energy. Herein, we perform a morphology and phase-controlled electrodeposition of MnO 2 with ultrahigh mass loading of 10 mg cm -2 on a carbon cloth substrate to achieve high overall capacitance without sacrificing the electrochemical performance. Under optimum conditions, a hierarchical nanostructured architecture was constructed by interconnection of primary two-dimensional ε-MnO 2 nanosheets and secondary one-dimensional α-MnO 2 nanorod arrays. The specific hetero-nanostructures ensure facile ionic and electric transport in the entire electrode and maintain the structure stability during cycling. The hierarchically structured MnO 2 electrode with high mass loading yields an outstanding areal capacitance of 3.04 F cm -2 (or a specific capacitance of 304 F g -1 ) at 3 mA cm -2 and an excellent rate capability comparable to those of low mass loading MnO 2 electrodes. Finally, the aqueous and all-solid asymmetric supercapacitors (ASCs) assembled with our MnO 2 cathode exhibit extremely high volumetric energy densities (8.3 mWh cm -3 at the power density of 0.28 W cm -3 for aqueous ASC and 8.0 mWh cm -3 at 0.65 W cm -3 for all-solid ASC), superior to most state-of-the-art supercapacitors.

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

Breault, Ronald W.; Monazam, Esmail R.; Shadle, Lawrence J.

Riser hydrodynamics are a function of the flow rates of gas and solids as well as the exit geometry, particularly when operated above the upper transport velocity. This work compares the exit voidage for multiple geometries and two different solids: Geldart group A glass beads and Geldart group B coke. Geometries were changed by modifying the volume of an abrupt T-shaped exit above the lateral riser exit. This was accomplished by positioning a plunger at various heights above the exit from zero to 0.38 m. A dimensionless expression used to predict smooth exit voidage was modified to account for themore » effect of the depth of the blind-T. The new correlation contains the solids-gas load ratio, solids-to-gas density ratio, bed-to-particle diameter ratio, gas Reynolds Number, as well as a term for the exit geometry. This study also found that there was a minimum riser roof height above the blind-T exit beyond which the riser exit voidage was not affected by the exit geometry. A correlation for this minimum riser roof height has also been developed in this study. This study covered riser superficial gas velocities of 4.35 to 7.7 m/s and solids circulation rates of 1.3 to 11.5 kg/s.« less

Sucrose ester stabilized solid lipid nanoparticles and nanostructured lipid carriers. II. Evaluation of the imidazole antifungal drug-loaded nanoparticle dispersions and their gel formulations.

PubMed

Das, Surajit; Ng, Wai Kiong; Tan, Reginald B H

2014-03-14

This study focused on: (i) feasibility of the previously developed sucrose ester stabilized SLNs and NLCs to encapsulate different imidazole antifungal drugs and (ii) preparation and evaluation of topical gel formulations of those SLNs and NLCs. Three imidazole antifungal drugs; clotrimazole, ketoconazole and climbazole were selected for this study. The results suggested that size, size distribution and drug encapsulation efficiency depend on the drug molecule and type of nanoparticles (SLN/NLC). The drug release experiment always showed faster drug release from NLCs than SLNs when the same drug molecule was loaded in both nanoparticles. However, drug release rate from both SLNs and NLCs followed the order of climbazole > ketoconazole > clotrimazole. NLCs demonstrated better physicochemical stability than SLNs in the case of all drugs. The drug release rate from ketoconazole- and clotrimazole-loaded SLNs became faster after three months than a fresh formulation. There was no significant change in drug release rate from climbazole-loaded SLNs and all drug-loaded NLCs. Gel formulations of SLNs and NLCs were prepared using polycarbophil polymer. Continuous flow measurements demonstrated non-Newtonian flow with shear-thinning behavior and thixotropy. Oscillation measurements depicted viscoelasticity of the gel formulations. Similar to nanoparticle dispersion, drug release rate from SLN- and NLC-gel was in the order of climbazole > ketoconazole > clotrimazole. However, significantly slower drug release was noticed from all gel formulations than their nanoparticle counterparts. Unlike nanoparticle dispersions, no significant difference in drug release from gel formulations containing SLNs and NLCs was observed for each drug. This study concludes that gel formulation of imidazole drug-loaded SLNs and NLCs can be used for sustained/prolonged topical delivery of the drugs.

Potential reductions of street solids and phosphorus in urban watersheds from street cleaning, Cambridge, Massachusetts, 2009-11

USGS Publications Warehouse

Sorenson, Jason R.

2013-01-01

Material accumulating and washing off urban street surfaces and ultimately into stormwater drainage systems represents a substantial nonpoint source of solids, phosphorus, and other constituent loading to waterways in urban areas. Cost and lack of usable space limit the type and number of structural stormwater source controls available to municipalities and other public managers. Non-structural source controls such as street cleaning are commonly used by cities and towns for construction, maintenance and aesthetics, and may reduce contaminant loading to waterways. Effectiveness of street cleaning is highly variable and potential improvements to water quality are not fully understood. In 2009, the U.S. Geological Survey, in cooperation with the Massachusetts Department of Environmental Protection, the U.S. Environmental Protection Agency, and the city of Cambridge, Massachusetts, and initiated a study to better understand the physical and chemical nature of the organic and inorganic solid material on street surfaces, evaluate the performance of a street cleaner at removing street solids, and make use of the Source Loading and Management Model (SLAMM) to estimate potential reductions in solid and phosphorus loading to the lower Charles River from various street-cleaning technologies and frequencies. Average yield of material on streets collected between May and December 2010, was determined to be about 740 pounds per curb-mile on streets in multifamily land use and about 522 pounds per curb-mile on commercial land-use streets. At the end-of-winter in March 2011, about 2,609 and 4,788 pounds per curb-mile on average were collected from streets in multifamily and commercial land-use types, respectively. About 86 percent of the total street-solid yield from multifamily and commercial land-use streets was greater than or equal to 0.125 millimeters in diameter (or very fine sand). Observations of street-solid distribution across the entire street width indicated that as much as 96 percent of total solids resided within 9 feet of the curb. Median accumulation rates of street solids and median washoff of street solids after rainstorms on multifamily and commercial land-use streets were also similar at about 33 and 22 pounds per curb-mile per day, and 35 and 40 percent, respectively. Results indicate that solids on the streets tested in Cambridge, Mass., can recover to pre-rainstorm yields within 1 to 3 days after washoff. The finer grain-size fractions tended to be more readily washed from the roadway surfaces during rainstorms. Street solids in the coarsest grain-size fraction on multifamily streets indicated an average net increase following rainstorms and are likely attributed to debris run-on from trees, lawns, and other plantings commonly found in residential areas. In seven experiments between May and December 2010, the median removal efficiency of solids from street surfaces following a single pass by a regenerative-air street cleaner was about 82 percent on study sites in the multifamily land-use streets and about 78 percent on the commercial land-use streets. Median street-solid removal efficiency increased with increasing grain size. This type of regenerative-air street cleaner left a median residual street-solid load on the street surface of about 100 pounds per curb-mile. Median concentrations of organic carbon and total phosphorus (P) on multifamily streets were about 35 and 29 percent greater, respectively, than those found on commercial streets. The median total mass of organic carbon and total P in street solids on multifamily streets was 68 and 75 percent greater, respectively, than those found on commercial streets. More than 87 percent of the mass of total P was determined to be in solids greater than or equal to 0.125 millimeters in diameter for both land-use types. The median total accumulation rate for total P on multifamily streets was about 5 times greater than on commercial streets. Total P accumulation in the medium grain-size fraction was nearly the same for streets within both land-use types at 0.004 pounds per curb-mile per day. Accumulation rates within the coarsest and finest grain-size fractions on multifamily streets were about 11 and 82 times greater than those on the commercial streets. Median washoff of total P was 58 and 48 percent from streets in multifamily and commercial land-use types, respectively, and generally increased with decreasing grain size. Total P median reductions resulting from a single pass of a regenerative-air street cleaner on streets in multifamily and commercial land-use types were about 82 and 62 percent, respectively, and were similar in terms of grain size between both land-use types. A Source Loading and Management Model for Microsoft Windows (WinSLAMM) was applied to a 21.8 acre subcatchment in Cambridge, Mass. The subcatchment area consists of mostly commercial and multifamily land-use types to evaluate the potential reductions of total and particulate solids, and P attributed to street cleaning. Rainwater runoff from rooftops represented between 20 and 50 percent of the total basin runoff. Street surfaces only accounted for about 20 percent of the total basin runoff. Monthly applications of mechanical-brush and vacuum-assisted street cleaners within the subcatchment as defined by SLAMM for areas with long-term (24-hour) on-street parking and monthly parking controls using five average climatic years resulted in total solid reductions of about 3 and 5 percent, respectively. Simulating the regenerative-air street cleaner tested as part of this study resulted in total solid reductions of about 16 percent. Increasing street cleaning frequency to three times weekly increased total solids removal for mechanical-brush, vacuum-assisted, and regenerative-air street cleaners to about 6, 14, and 19 percent, respectively. Monthly applications of mechanical-brush, vacuum-assisted, and regenerative-air street cleaners within the subcatchment resulted in total P reductions of about 1, 3, and 8 percent, respectively. A street cleaning frequency of three times each week for each of the three street-cleaner types increased total P removal to about 3, 7, and 9 percent, respectively.

The effect of riser end geometry on gas-solid hydrodynamics in a CFB riser operating in the core annular and dilute homogeneous flow regimes

DOE PAGES

Breault, Ronald W.; Monazam, Esmail R.; Shadle, Lawrence J.; ...

2017-02-12

Riser hydrodynamics are a function of the flow rates of gas and solids as well as the exit geometry, particularly when operated above the upper transport velocity. This work compares the exit voidage for multiple geometries and two different solids: Geldart group A glass beads and Geldart group B coke. Geometries were changed by modifying the volume of an abrupt T-shaped exit above the lateral riser exit. This was accomplished by positioning a plunger at various heights above the exit from zero to 0.38 m. A dimensionless expression used to predict smooth exit voidage was modified to account for themore » effect of the depth of the blind-T. The new correlation contains the solids-gas load ratio, solids-to-gas density ratio, bed-to-particle diameter ratio, gas Reynolds Number, as well as a term for the exit geometry. This study also found that there was a minimum riser roof height above the blind-T exit beyond which the riser exit voidage was not affected by the exit geometry. A correlation for this minimum riser roof height has also been developed in this study. This study covered riser superficial gas velocities of 4.35 to 7.7 m/s and solids circulation rates of 1.3 to 11.5 kg/s.« less

Solid tumors are poroelastic solids with a chemo-mechanical feedback on growth.

PubMed

Ambrosi, D; Pezzuto, S; Riccobelli, D; Stylianopoulos, T; Ciarletta, P

2017-12-01

The experimental evidence that a feedback exists between growth and stress in tumors poses challenging questions. First, the rheological properties (the "constitutive equations") of aggregates of malignant cells are still a matter of debate. Secondly, the feedback law (the "growth law") that relates stress and mitotic-apoptotic rate is far to be identified. We address these questions on the basis of a theoretical analysis of in vitro and in vivo experiments that involve the growth of tumor spheroids. We show that solid tumors exhibit several mechanical features of a poroelastic material, where the cellular component behaves like an elastic solid. When the solid component of the spheroid is loaded at the boundary, the cellular aggregate grows up to an asymptotic volume that depends on the exerted compression. Residual stress shows up when solid tumors are radially cut, highlighting a peculiar tensional pattern. By a novel numerical approach we correlate the measured opening angle and the underlying residual stress in a sphere. The features of the mechanobiological system can be explained in terms of a feedback of mechanics on the cell proliferation rate as modulated by the availability of nutrient, that is radially damped by the balance between diffusion and consumption. The volumetric growth profiles and the pattern of residual stress can be theoretically reproduced assuming a dependence of the target stress on the concentration of nutrient which is specific of the malignant tissue.

Demonstration-scale evaluation of a novel high-solids anaerobic digestion process for converting organic wastes to fuel gas and compost.

PubMed

Rivard, C J; Duff, B W; Dickow, J H; Wiles, C C; Nagle, N J; Gaddy, J L; Clausen, E C

1998-01-01

Early evaluations of the bioconversion potential for combined wastes such as tuna sludge and sorted municipal solid waste (MSW) were conducted at laboratory scale and compared conventional low-solids, stirred-tank anaerobic systems with the novel, high-solids anaerobic digester (HSAD) design. Enhanced feedstock conversion rates and yields were determined for the HSAD system. In addition, the HSAD system demonstrated superior resiliency to process failure. Utilizing relatively dry feedstocks, the HSAD system is approximately one-tenth the size of conventional low-solids systems. In addition, the HSAD system is capable of organic loading rates (OLRs) on the order of 20-25 g volatile solids per liter digester volume per d (gVS/L/d), roughly 4-5 times those of conventional systems. Current efforts involve developing a demonstration-scale (pilot-scale) HSAD system. A two-ton/d plant has been constructed in Stanton, CA and is currently in the commissioning/startup phase. The purposes of the project are to verify laboratory- and intermediate-scale process performance; test the performance of large-scale prototype mechanical systems; demonstrate the long-term reliability of the process; and generate the process and economic data required for the design, financing, and construction of full-scale commercial systems. This study presents conformational fermentation data obtained at intermediate-scale and a snapshot of the pilot-scale project.

Solid-State NMR Investigation of Drug-Excipient Interactions and Phase Behavior in Indomethacin-Eudragit E Amorphous Solid Dispersions.

PubMed

Lubach, Joseph W; Hau, Jonathan

2018-02-20

To investigate the nature of drug-excipient interactions between indomethacin (IMC) and methacrylate copolymer Eudragit® E (EE) in the amorphous state, and evaluate the effects on formulation and stability of these amorphous systems. Amorphous solid dispersions containing IMC and EE were spray dried with drug loadings from 20% to 90%. PXRD was used to confirm the amorphous nature of the dispersions, and DSC was used to measure glass transition temperatures (T g ). 13 C and 15 N solid-state NMR was utilized to investigate changes in local structure and protonation state, while 1 H T 1 and T 1ρ relaxation measurements were used to probe miscibility and phase behavior of the dispersions. T g values for IMC-EE solid dispersions showed significant positive deviations from predicted values in the drug loading range of 40-90%, indicating a relatively strong drug-excipient interaction. 15 N solid-state NMR exhibited a change in protonation state of the EE basic amine, with two distinct populations for the EE amine at -360.7 ppm (unprotonated) and -344.4 ppm (protonated). Additionally, 1 H relaxation measurements showed phase separation at high drug load, indicating an amorphous ionic complex and free IMC-rich phase. PXRD data showed all ASDs up to 90% drug load remained physically stable after 2 years. 15 N solid-state NMR experiments show a change in protonation state of EE, indicating that an ionic complex indeed forms between IMC and EE in amorphous solid dispersions. Phase behavior was determined to exhibit nanoscale phase separation at high drug load between the amorphous ionic complex and excess free IMC.

A data reconnaissance on the effect of suspended-sediment concentrations on dissolved-solids concentrations in rivers and tributaries in the Upper Colorado River Basin

USGS Publications Warehouse

Tillman, Fred D.; Anning, David W.

2014-01-01

The Colorado River is one of the most important sources of water in the western United States, supplying water to over 35 million people in the U.S. and 3 million people in Mexico. High dissolved-solids loading to the River and tributaries are derived primarily from geologic material deposited in inland seas in the mid-to-late Cretaceous Period, but this loading may be increased by human activities. High dissolved solids in the River causes substantial damages to users, primarily in reduced agricultural crop yields and corrosion. The Colorado River Basin Salinity Control Program was created to manage dissolved-solids loading to the River and has focused primarily on reducing irrigation-related loading from agricultural areas. This work presents a reconnaissance of existing data from sites in the Upper Colorado River Basin (UCRB) in order to highlight areas where suspended-sediment control measures may be useful in reducing dissolved-solids concentrations. Multiple linear regression was used on data from 164 sites in the UCRB to develop dissolved-solids models that include combinations of explanatory variables of suspended sediment, flow, and time. Results from the partial t-test, overall likelihood ratio, and partial likelihood ratio on the models were used to group the sites into categories of strong, moderate, weak, and no-evidence of a relation between suspended-sediment and dissolved-solids concentrations. Results show 68 sites have strong or moderate evidence of a relation, with drainage areas for many of these sites composed of a large percentage of clastic sedimentary rocks. These results could assist water managers in the region in directing field-scale evaluation of suspended-sediment control measures to reduce UCRB dissolved-solids loading.

Effects of agitation on particle-size distribution and enzymatic hydrolysis of pretreated spruce and giant reed.

PubMed

Kadić, Adnan; Palmqvist, Benny; Lidén, Gunnar

2014-01-01

Mixing is an energy demanding process which has been previously shown to affect enzymatic hydrolysis. Concentrated biomass slurries are associated with high and non-Newtonian viscosities and mixing in these systems is a complex task. Poor mixing can lead to mass and/or heat transfer problems as well as inhomogeneous enzyme distribution, both of which can cause possible yield reduction. Furthermore the stirring energy dissipation may impact the particle size which in turn may affect the enzymatic hydrolysis. The objective of the current work was to specifically quantify the effects of mixing on particle-size distribution (PSD) and relate this to changes in the enzymatic hydrolysis. Two rather different materials were investigated, namely pretreated Norway spruce and giant reed. Changes in glucan hydrolysis and PSD were measured as a function of agitation during enzymatic hydrolysis at fiber loadings of 7 or 13% water-insoluble solids (WIS). Enzymatic conversion of pretreated spruce was strongly affected by agitation rates at the higher WIS content. However, at low WIS content the agitation had almost no effect on hydrolysis. There was some effect of agitation on the hydrolysis of giant reed at high WIS loading, but it was smaller than that for spruce, and there was no measurable effect at low WIS loading. In the case of spruce, intense agitation clearly affected the PSD and resulted in a reduced mean particle size, whereas for giant reed the decrease in particle size was mainly driven by enzymatic action. However, the rate of enzymatic hydrolysis was not increased after size reduction by agitation. The impact of agitation on the enzymatic hydrolysis clearly depends not only on feedstock but also on the solids loading. Agitation was found to affect the PSD differently for the examined pretreated materials spruce and giant reed. The fact that the reduced mean particle diameter could not explain the enhanced hydrolysis rates found for spruce at an elevated agitation suggests that mass transfer at sustained high viscosities plays an important role in determining the rate of enzymatic hydrolysis.

Effect of hydroxypropylcellulose and Tween 80 on physicochemical properties and bioavailability of ezetimibe-loaded solid dispersion.

PubMed

Rashid, Rehmana; Kim, Dong Wuk; Din, Fakhar Ud; Mustapha, Omer; Yousaf, Abid Mehmood; Park, Jong Hyuck; Kim, Jong Oh; Yong, Chul Soon; Choi, Han-Gon

2015-10-05

The purpose of this research was to evaluate the effect of the HPC (hydroxypropylcellulose) and Tween 80 on the physicochemical properties and oral bioavailability of ezetimibe-loaded solid dispersions. The binary solid dispersions were prepared with drug and various amounts of HPC. Likewise, ternary solid dispersions were prepared with different ratios of drug, HPC and Tween 80. Both types of solid dispersions were prepared using the solvent evaporation method. Their aqueous solubility, physicochemical properties, dissolution and oral bioavailability were investigated in comparison with the drug powder. All the solid dispersions significantly improved the drug solubility and dissolution. As the amount of HPC increased in the binary solid dispersions to 10-fold, the drug solubility and dissolution were increased accordingly. However, further increase in HPC did not result in significant differences among them. Similarly, up to 0.1-fold, Tween 80 increased the drug solubility in the ternary solid dispersions followed by no significant change. However, Tween 80 hardly affected the drug dissolution. The physicochemical analysis proved that the drug in binary and ternary solid dispersion was existed in the amorphous form. The particle-size measurements of these formulations were also not significantly different from each other, which showed that Tween 80 had no impact on physicochemical properties. The ezetimibe-loaded binary and ternary solid dispersions gave 1.6- and 1.8-fold increased oral bioavailability in rats, respectively, as compared to the drug powder; however, these values were not significantly different from each other. Thus, HPC greatly affected the solubility, dissolution and oral bioavailability of drug, but Tween 80 hardly did. Furthermore, this ezetimibe-loaded binary solid dispersion prepared only with HPC would be suggested as a potential formulation for oral administration of ezetimibe. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Anaerobic co-digestion of corn stalk and vermicompost].

PubMed

Chen, Guang-yin; Zheng, Zheng; Zou, Xing-xing; Fang, Cai-xia; Luo, Yan

2010-02-01

The characteristics of corn stalk digested alone at different total solid (TS) loading rates and co-digestion of various proportions of corn stalk and vermicompost were investigated by batch model at 35 degrees C +/- 1 degrees C. The organic loading rates (OLRs) studied were in the range of 1.2%-6.0% TS and increasing proportions of vermicompost from 20% to 80% TS. A maximum methane yield of corn stalk digested alone was 217.60 mL/g obtained at the TS loading rate of 4.8%. However, when the TS loading rate was 6.0%, the anaerobic system was acidified and the lowest pH value was 5.10 obtained on day 4 and the biogas productivity decreased. Furthermore, co-digestion of vermicompost and corn stalk in varying proportions were investigated at constant of 6.0% TS. Co-digestion with vermicompost improved the biodegradability of corn stalk and the methane yield was improved by 4.42%-58.61%, and led to higher pH values, higher volatile fatty acids (VFAs) concentration and lower alkalinity content compared with corn stalk digested alone. The maximum biogas yield and methane yield of 410.30 mL/g and 259. 35 mL/g were obtained for 40% vermicompost and 60% corn stalk respectively. Compared with corn stalk digested alone, co-digested with vermicompost didn' t affect methane content and the fermentation type, but promoted the destruction of crystalline of cellulose and the highest destruction rate was 29.36% for 40% vermicompost and 60% corn stalk. Therefore, adding vermicompost was beneficial for the decomposition and increasing the biotransformation rate of corn stalk.

Three-dimensional multi-physics coupled simulation of ignition transient in a dual pulse solid rocket motor

NASA Astrophysics Data System (ADS)

Li, Yingkun; Chen, Xiong; Xu, Jinsheng; Zhou, Changsheng; Musa, Omer

2018-05-01

In this paper, numerical investigation of ignition transient in a dual pulse solid rocket motor has been conducted. An in-house code has been developed in order to solve multi-physics governing equations, including unsteady compressible flow, heat conduction and structural dynamic. The simplified numerical models for solid propellant ignition and combustion have been added. The conventional serial staggered algorithm is adopted to simulate the fluid structure interaction problems in a loosely-coupled manner. The accuracy of the coupling procedure is validated by the behavior of a cantilever panel subjected to a shock wave. Then, the detailed flow field development, flame propagation characteristics, pressure evolution in the combustion chamber, and the structural response of metal diaphragm are analyzed carefully. The burst-time and burst-pressure of the metal diaphragm are also obtained. The individual effects of the igniter's mass flow rate, metal diaphragm thickness and diameter on the ignition transient have been systemically compared. The numerical results show that the evolution of the flow field in the combustion chamber, the temperature distribution on the propellant surface and the pressure loading on the metal diaphragm surface present a strong three-dimensional behavior during the initial ignition stage. The rupture of metal diaphragm is not only related to the magnitude of pressure loading on the diaphragm surface, but also to the history of pressure loading. The metal diaphragm thickness and diameter have a significant effect on the burst-time and burst-pressure of metal diaphragm.

Paper sludge (PS) to bioethanol: Evaluation of virgin and recycle mill sludge for low enzyme, high-solids fermentation.

PubMed

Boshoff, Sonja; Gottumukkala, Lalitha Devi; van Rensburg, Eugéne; Görgens, Johann

2016-03-01

Paper sludge (PS) from the paper and pulp industry consists primarily of cellulose and ash and has significant potential for ethanol production. Thirty-seven PS samples from 11 South African paper and pulp mills exhibited large variation in chemical composition and resulting ethanol production. Simultaneous saccharification and fermentation (SSF) of PS in fed-batch culture was investigated at high solid loadings and low enzyme dosages. Water holding capacity and viscosity of the PS influenced ethanol production at elevated solid loadings of PS. High viscosity of PS from virgin pulp mills restricted the solid loading to 18% (w/w) at an enzyme dosage of 20 FPU/gram dry PS (gdPS), whereas an optimal solid loading of 27% (w/w) was achieved with corrugated recycle mill PS at 11 FPU/gdPS. Ethanol concentration and yield of virgin pulp and corrugated recycle PS were 34.2g/L at 66.9% and 45.5 g/L at 78.2%, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

Regenerable sorbent technique for capturing CO.sub.2 using immobilized amine sorbents

DOEpatents

Pennline, Henry W; Hoffman, James S; Gray, McMahan L; Fauth, Daniel J; Resnik, Kevin P

2013-08-06

The disclosure provides a CO.sub.2 absorption method using an amine-based solid sorbent for the removal of carbon dioxide from a gas stream. The method disclosed mitigates the impact of water loading on regeneration by utilizing a conditioner following the steam regeneration process, providing for a water loading on the amine-based solid sorbent following CO.sub.2 absorption substantially equivalent to the moisture loading of the regeneration process. This assists in optimizing the CO.sub.2 removal capacity of the amine-based solid sorbent for a given absorption and regeneration reactor size. Management of the water loading in this manner allows regeneration reactor operation with significant mitigation of energy losses incurred by the necessary desorption of adsorbed water.

[Municipal biowaste thermal-hydrolysis and ASBR anaerobic digestion].

PubMed

Hou, Hua-hua; Wang, Wei; Hu, Song; Xu, Yi-xian

2010-02-01

Thermal-hydrolysis can remarkably improve the solid organics dissolving efficiency of urban biomass waste, and anaerobic sequencing batch reactor (ASBR) was used to improve the efficiency of urban biomass waste anaerobic digestion. The optimum thermal-hydrolysis temperature and holding time was 175 degrees C and 60 min, the volatile suspended solid (VSS) dissolving ratio of kitchen waste, fruit-and-vegetable waste and sludge were 31.3%, 31.9% and 49.7%, respectively. Two ASBR and one continuous-flow stirred tank reactor (CSTR) were started at hydraulic retention time (HRT) = 20 d, COD organic loading rate (OLR) = 3.2-3.6 kg/(m3 x d). The biogas production volumes were 5656 mL/d(A1), 6335 mL/d(A2) and 3 103 mL/d(CSTR), respectively; VSS degradation ratios were 45.3% (A1), 50.87% (A2), 20.81% (CSTR), and the total COD (TCOD) removal rates were 88.1% (A1), 90% (A2), 72.6% (CSTR). In ASBR, organic solid and anaerobic microorganism were remained in the reactor during settling period. When HRT was 20 d, the solid retention time (SRT) was over 130 d, which made ASBR higher efficiency than CSTR.

Solid lipid nanoparticles by coacervation loaded with a methotrexate prodrug: preliminary study for glioma treatment.

PubMed

Battaglia, Luigi; Muntoni, Elisabetta; Chirio, Daniela; Peira, Elena; Annovazzi, Laura; Schiffer, Davide; Mellai, Marta; Riganti, Chiara; Salaroglio, Iris Chiara; Lanotte, Michele; Panciani, Pierpaolo; Capucchio, Maria Teresa; Valazza, Alberto; Biasibetti, Elena; Gallarate, Marina

2017-03-01

Methotrexate-loaded biocompatible nanoparticles were tested for preliminary efficacy in glioma treatment. Behenic acid nanoparticles, prepared by the coacervation method, were loaded with the ester prodrug didodecylmethotrexate, which was previously tested in vitro against glioblastoma human primary cultures. Nanoparticle conjugation with an ApoE mimicking chimera peptide was performed to obtain active targeting to the brain. Biodistribution studies in healthy rats assessed the superiority of ApoE-conjugated formulation, which was tested on an F98/Fischer glioma model. Differences were observed in tumor growth rate (measured by MRI) between control and treated rats. In vitro tests on F98 cultured cells assessed their susceptibility to treatment, with consequent apoptosis, and allowed us to explain the apoptosis observed in glioma models.

Fluvial sediment transport in a glacier-fed high-mountain river (Riffler Bach, Austrian Alps)

NASA Astrophysics Data System (ADS)

Morche, David; Weber, Martin; Faust, Matthias; Schuchardt, Anne; Baewert, Henning

2017-04-01

High-alpine environments are strongly affected by glacier retreat since the Little Ice Age (LIA). Due to ongoing climate change the hydrology of proglacial rivers is also influenced. It is expected that the growing proportions of snow melt and rainfall events will change runoff characteristics of proglacial rivers. Additionally, the importance of paraglacial sediment sources in recently deglaciating glacier forefields is increasing, while the role of glacial erosion is declining. Thus complex environmental conditions leading to a complex pattern of fluvial sediment transport in partly glaciated catchments of the European Alps. Under the umbrella of the joint PROSA-project the fluvial sediment transport of the river Riffler Bach (Kaunertal, Tyrol, Austria) was studied in 3 consecutive ablation seasons in order to quantify sediment yields. In June 2012 a probe for water level and an automatic water sampler (AWS) were installed at the outlet of the catchment (20km2). In order to calculate annual stage-discharge-relations by the rating-curve approach, discharge (Q) was repeatedly measured with current meters and by salt dilution. Concurrent to the discharge measurements bed load was collected using a portable Helley-Smith sampler. Bed load samples were weighted and sieved in the laboratory to gain annual bed load rating curves and grain size distributions. In total 564 (2012: 154, 2013: 209, 2014: 201) water samples were collected and subsequently filtered to quantify suspended sediment concentrations (SSC). Q-SSC-relations were calculated for single flood events due to the high variability of suspended sediment transport. The results show a high inter- and intra-annual variability of solid fluvial sediment transport, which can be explained by the characteristics of suspended sediment transport. Only 13 of 22 event-based Q-SSC-relations show causal dependency. In 2012, during a period with multiple pluvial-induced peak discharges most sediment was transported. On the contrary the importance of snow melt for sediment transport was indicated during the ablation season 2013. In total 3582 t of sediment were exported out of the Riffler Bach catchment in 2012, which is almost twice the solid sediment load of the ablation season 2013 (1953 t). Total solid load of the Riffler Bach River was 3511 t in 2014 Suspended sediment load was dominant in all ablation seasons. The result of additional DEM analysis reveals that 37 % of the catchment do not contribute or only contribute to a lesser amount to the fluvial sediment export out of the catchment. The findings of the grain size analysis imply glacigenic origin of the transported particles. Thus, the results indicate that solid sediment transport is not only a function of discharge. Also availability of sediment and the systems state of (dis-)connectivity, e.g. coupling of sediment sources to the river, need to be considered.

Radial pressure profiles in a cold‐flow gas‐solid vortex reactor

PubMed Central

Pantzali, Maria N.; Kovacevic, Jelena Z.; Marin, Guy B.; Shtern, Vladimir N.

2015-01-01

A unique normalized radial pressure profile characterizes the bed of a gas‐solid vortex reactor over a range of particle densities and sizes, solid capacities, and gas flow rates: 950–1240 kg/m3, 1–2 mm, 2 kg to maximum solids capacity, and 0.4–0.8 Nm3/s (corresponding to gas injection velocities of 55–110 m/s), respectively. The combined momentum conservation equations of both gas and solid phases predict this pressure profile when accounting for the corresponding measured particle velocities. The pressure profiles for a given type of particles and a given solids loading but for different gas injection velocities merge into a single curve when normalizing the pressures with the pressure value downstream of the bed. The normalized—with respect to the overall pressure drop—pressure profiles for different gas injection velocities in particle‐free flow merge in a unique profile. © 2015 The Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers AIChE J, 61: 4114–4125, 2015 PMID:27667827

Effect of temperature and gap opening rate on the resiliency of candidate solid rocket booster O-ring materials

NASA Technical Reports Server (NTRS)

Lach, Cynthia L.

1992-01-01

In the redesign of the Space Shuttle solid rocket motor following the Challenger accident, the field and nozzle-to-case joints were designed to minimize gap opening caused by internal motor pressurization during ignition. The O-ring seals and glands for these joints were designed both to accommodate structural deflections and to promote pressure assisted sealing. The resiliency behavior of several candidate O-ring materials was evaluated for the effects of temperature and gap opening rates. The performance of three of the elastomeric materials was tested under the specific redesign gap opening requirement. Dynamic flexure conditions unique to launch produce low frequency vibrations in the gap opening. The effect of these vibrations on the ability of the O-ring to maintain contact with the sealing surface was addressed. The resiliency of the O-ring materials was found to be extremely sensitive to variations in temperature and gap opening rate. The top three elastomeric materials tracked the simulated solid rocket booster (SRB) field joint deflection at 75 and 120 F. The external tank/SRB attach strut load vibrations had a negligible effect on the ability of the O-ring to track the simulated SRB field joint deflection.

Effect of Strengthening Mechanism on Strain-Rate Related Tensile Properties of Low-Carbon Sheet Steels for Automotive Application

NASA Astrophysics Data System (ADS)

Das, Anindya; Biswas, Pinaki; Tarafder, S.; Chakrabarti, D.; Sivaprasad, S.

2018-05-01

In order to ensure crash resistance of the steels used in automotive components, the ensile deformation behavior needs to be studied and predicted not only under quasi-static condition, but also under dynamic loading rates. In the present study, tensile tests have been performed on four different automobile grade sheet steels, namely interstitial free steel, dual-phase 600 and 800, and a carbon manganese steel over the strain rate regime of 0.001-800/s. Apart from the variation in strength (which always increased with strain rate), the effect of strengthening mechanism on strain rate sensitivity and strain hardening behavior has been evaluated. Strain rate sensitivity was found to increase at high-strain rate regime for all the steels. Contribution of solid solution hardening on strain rate sensitivity at lower plastic strains was found to be higher compared to dislocation strengthening and second-phase hardening. However, precipitation hardening coupled with solid solution hardening produced the highest strain rate sensitivity, in C-Mn-440 steel at high strain rates. Different strain-rate-sensitive models which take into account the change in yield stress and strain hardening behavior with strain rate for ductile materials were used to predict the flow behavior of these sheet steels at strain rates up to 800/s.

Vent modification of large ribbon parachutes to enhance cluster performance

NASA Technical Reports Server (NTRS)

Kolega, D. J.; Woodis, W. R.; Reuter, J. D.

1986-01-01

Due to uneven load sharing and lagging inflation rates, the design of the Large Main Parachute (LMP) cluster, used to recover the Space Shuttle steel case Solid Rocket Boosters, had to be modified. The cause of the problem was excessive variation in effective porosity in the crown area of the LMP during first stage inflation. The design modification consisted of adding horizontal ribbons above the existing vent band to reduce the vent porosity and better control the position and attitude of the vent lines. Performance of modified LMP's since introduction indicates that the load sharing between the clustered chutes has been significantly improved.

Effect of Agitation on Acidogenesis Stage of Two-Stage Anaerobic Digestion of Palm Oil Mill Effluent (POME) into Biogas

NASA Astrophysics Data System (ADS)

Trisakti, B.; Irvan; Adipasah, H.; Taslim; Turmuzi, M.

2017-03-01

The acidogenesis stage in two-stage anaerobic digestion of palm oil mill effluent (POME) was studied in a continuous stirred tank reactor (CSTR). This research investigated the effect of agitation rate on the growth of microorganisms, the degradation of organic substances, and volatile fatty acids (VFA) production and composition. Initially, the suitable loading up was determined by varying the HRT 6.7, 5.0, and 4.0 days in a 2 L CSTR with agitation rate 50 rpm, pH 6.0 ± 0.2, at room temperature. Next, effect of agitation on the process was determined by varying agitation rate at 25, 50, 100, and 200 rpm. Analysis of total solids (TS), volatile solids (VS), total suspended solids (TSS), volatile suspended solids (VSS), chemical oxygen demand (COD), and volatile fatty acids (VFA) were conducted in order to study the growth of microorganisms and their abilities in converting organic compound to produce VFA. The highest growth of microorganisms was achieved at HRT 4.0 day with microorganism concentration was 20.62 mg VSS/L and COD reduction was 15.7%. The highest production of total VFA achieved was 5,766.61 mg/L mg/L at agitation rate 200 rpm, with concentration of acetic acid, propionic acid and butyric acid were 1,889.23; 1,161.43; and 2,725.95 mg/L, respectively. While degradation VS and COD were 16.61 and 38.79%.

Kinetics of enzymatic high-solid hydrolysis of lignocellulosic biomass studied by calorimetry.

PubMed

Olsen, Søren N; Lumby, Erik; McFarland, Kc; Borch, Kim; Westh, Peter

2011-03-01

Enzymatic hydrolysis of high-solid biomass (>10% w/w dry mass) has become increasingly important as a key step in the production of second-generation bioethanol. To this end, development of quantitative real-time assays is desirable both for empirical optimization and for detailed kinetic analysis. In the current work, we have investigated the application of isothermal calorimetry to study the kinetics of enzymatic hydrolysis of two substrates (pretreated corn stover and Avicel) at high-solid contents (up to 29% w/w). It was found that the calorimetric heat flow provided a true measure of the hydrolysis rate with a detection limit of about 500 pmol glucose s(-1). Hence, calorimetry is shown to be a highly sensitive real-time method, applicable for high solids, and independent on the complexity of the substrate. Dose-response experiments with a typical cellulase cocktail enabled a multidimensional analysis of the interrelationships of enzyme load and the rate, time, and extent of the reaction. The results suggest that the hydrolysis rate of pretreated corn stover is limited initially by available attack points on the substrate surface (<10% conversion) but becomes proportional to enzyme dosage (excess of attack points) at later stages (>10% conversion). This kinetic profile is interpreted as an increase in polymer end concentration (substrate for CBH) as the hydrolysis progresses, probably due to EG activity in the enzyme cocktail. Finally, irreversible enzyme inactivation did not appear to be the source of reduced hydrolysis rate over time.

Bioethanol production: an integrated process of low substrate loading hydrolysis-high sugars liquid fermentation and solid state fermentation of enzymatic hydrolysis residue.

PubMed

Chu, Qiulu; Li, Xin; Ma, Bin; Xu, Yong; Ouyang, Jia; Zhu, Junjun; Yu, Shiyuan; Yong, Qiang

2012-11-01

An integrated process of enzymatic hydrolysis and fermentation was investigated for high ethanol production. The combination of enzymatic hydrolysis at low substrate loading, liquid fermentation of high sugars concentration and solid state fermentation of enzymatic hydrolysis residue was beneficial for conversion of steam explosion pretreated corn stover to ethanol. The results suggested that low substrate loading hydrolysis caused a high enzymatic hydrolysis yield; the liquid fermentation of about 200g/L glucose by Saccharomyces cerevisiae provided a high ethanol concentration which could significantly decrease cost of the subsequent ethanol distillation. A solid state fermentation of enzymatic hydrolysis residue was combined, which was available to enhance ethanol production and cellulose-to-ethanol conversion. The results of solid state fermentation demonstrated that the solid state fermentation process accompanied by simultaneous saccharification and fermentation. Copyright © 2012 Elsevier Ltd. All rights reserved.

Watershed Effects on Streamflow Quantity and Quality in Six Watersheds of Gwinnett County, Georgia

USGS Publications Warehouse

Landers, Mark N.; Ankcorn, Paul D.; McFadden, Keith W.

2007-01-01

Watershed management is critical for the protection and enhancement of streams that provide multiple benefits for Gwinnett County, Georgia, and downstream communities. Successful watershed management requires an understanding of how stream quality is affected by watershed characteristics. The influence of watershed characteristics on stream quality is complex, particularly for the nonpoint sources of pollutants that affect urban watersheds. The U.S. Geological Survey (USGS), in cooperation with Gwinnett County Department of Water Resources (formerly known as Public Utilities), established a water-quality monitoring program during late 1996 to collect comprehensive, consistent, high-quality data for use by watershed managers. Between 1996 and 2003, more than 10,000 analyses were made for more than 430 water-quality samples. Continuous-flow and water-quality data have been collected since 1998. Loads have been computed for selected constituents from 1998 to 2003. Changing stream hydrology is a primary driver for many other water-quality and aquatic habitat effects. Primary factors affecting stream hydrology (after watershed size and climate) within Gwinnett County are watershed slope and land uses. For the six study watersheds in Gwinnett County, watershedwide imperviousness up to 12 percent does not have a well-defined influence on stream hydrology, whereas two watersheds with 21- and 35-percent impervious area are clearly impacted. In the stream corridor, however, imperviousness from 1.6 to 4.4 percent appears to affect baseflow and stormflow for all six watersheds. Relations of concentrations to discharge are used to develop regression models to compute constituent loads using the USGS LOAD ESTimator model. A unique method developed in this study is used to calibrate the model using separate baseflow and stormflow sample datasets. The method reduced model error and provided estimates of the load associated with the baseflow and stormflow parts of the hydrograph. Annual load of total suspended sediment is a performance criterion in Gwinnett County's Watershed Protection Plan. Median concentrations of total suspended solids in stormflow range from 30 to 180 times greater than in baseflow. This increase in total suspended solids concentration with increasing discharge has a multiplied effect on total suspended solids load, 97 to 99 percent of which is transported during stormflow. Annual total suspended solids load is highly dependent on annual precipitation; between 1998 and 2003 load for the wettest year was up to 28 times greater than for the driest year. Average annual total suspended solids yield from 1998-2003 in the six watersheds increased with high-density and transportation/utility land uses, and generally decreased with low-density residential, estate/park, and undeveloped land uses. Watershed characteristics also were related to annual loads of total phosphorus, dissolved phosphorus, total nitrogen, total dissolved solids, biochemical oxygen demand, and total zinc, as well as stream alkalinity. Flow-adjusted total suspended solids, total phosphorus, and total zinc stormflow concentrations between 1996 and 2003 have a seasonal pattern in five of the six watersheds. Flow-adjusted concentrations typically peak during late summer, between July and August. The seasonal pattern is stronger for more developed watersheds and may be related to seasonal land-disturbance activities and/or to seasonal rainfall intensity, both of which increase in summer. Adjusting for seasonality in the computation of constituent load caused the standard error of annual total suspended solids load to improve by an average of 11 percent, and increased computed summer total suspended solids loads by an average of 45 percent and decreased winter total suspended solids loads by an average of 40 percent. Total annual loads changed by less than 5 percent on the average. Graphical and statistical analyses do not indicate a time tre

Nitrogen removal from landfill leachate via ex situ nitrification and sequential in situ denitrification

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

Zhong Qi; Graduate School of Chinese Academy of Sciences, Beijing 100049; Li Daping

2009-04-15

Ex situ nitrification and sequential in situ denitrification represents a novel approach to nitrogen management at landfills. Simultaneous ammonia and organics removal was achieved in a continuous stirred tank reactor (CSTR). The results showed that the maximum nitrogen loading rate (NLR) and the maximum organic loading rate (OLR) was 0.65 g N l{sup -1} d{sup -1} and 3.84 g COD l{sup -1} d{sup -1}, respectively. The ammonia and chemical oxygen demand (COD) removal was over 99% and 57%, respectively. In the run of the CSTR, free ammonia (FA) inhibition and low dissolved oxygen (DO) were found to be key factorsmore » affecting nitrite accumulation. In situ denitrification was studied in a municipal solid waste (MSW) column by recalculating nitrified leachate from CSTR. The decomposition of MSW was accelerated by the recirculation of nitrified leachate. Complete reduction of total oxidized nitrogen (TON) was obtained with maximum TON loading of 28.6 g N t{sup -1} TS d{sup -1} and denitrification was the main reaction responsible. Additionally, methanogenesis inhibition was observed while TON loading was over 11.4 g N t{sup -1} TS d{sup -1} and the inhibition was enhanced with the increase of TON loading.« less

Cytomegalovirus (CMV) DNA load predicts relapsing CMV infection after solid organ transplantation.

PubMed

Sia, I G; Wilson, J A; Groettum, C M; Espy, M J; Smith, T F; Paya, C V

2000-02-01

Cytomegalovirus (CMV) DNA load was analyzed as a marker for relapse of CMV infection in 24 solid organ transplant patients with CMV infection or disease who received a fixed 14-day course of intravenous ganciclovir. Viral load was measured in blood samples obtained before and at the completion of treatment. Eight (33%) of 24 patients developed relapsing CMV infection. Median pretreatment viral loads were higher in the relapsing group (80,150 copies/106 leukocytes) than in the nonrelapsing group (5500 copies/106 leukocytes; P=.007). The relapsing group also had persistent detectable viral DNA (median, 5810 copies/106 leukocytes) after treatment, whereas it was undetectable in the nonrelapsing group (P<. 0001). Primary CMV infection (seronegative recipients of seropositive organs, D+R-) was an independent marker for CMV relapse (P=.03), and these patients had higher pre- and posttreatment viral loads than did non-D+/R- patients (P<.0001 and P=.0014, respectively). CMV DNA load is a useful marker for individualizing antiviral treatment of CMV infection in solid organ transplant recipients.

Development of novel fast-dissolving tacrolimus solid dispersion-loaded prolonged release tablet.

PubMed

Cho, Jung Hyun; Kim, Yong-Il; Kim, Dong-Wuk; Yousaf, Abid Mehmood; Kim, Jong Oh; Woo, Jong Soo; Yong, Chul Soon; Choi, Han-Gon

2014-04-11

The goal of this research was to develop a novel prolonged release tablet bioequivalent to the commercial sustained release capsule. A number of tacrolimus-loaded fast-dissolving solid dispersions containing various amounts of DOSS were prepared using the spray drying technique. Their solubility, dissolution and pharmacokinetics in rats were studied. DOSS increased drug solubility and dissolution in the solid dispersions. Compared with the drug powder, the solubility, dissolution and bioavailability of tacrolimus with the fast-dissolving solid dispersion containing tacrolimus/HP-β-CD/DOSS in the weight ratio of 5:40:4 were boosted by approximately 700-, 30- and 2-fold, respectively. Several tablet formulations were accomplished with this solid dispersion in combination with various ratios of HPMC/ethylcellulose. The release behaviour and pharmacokinetic studies in beagle dogs were assessed compared with the commercial prolonged release capsule. A decrease in HPMC/ethylcellulose ratios reduced the dissolution of tacrolimus from the tablets. Particularly, the tacrolimus-loaded prolonged release tablet consisting of fast-dissolving tacrolimus solid dispersion, HPMC, ethylcellulose and talc at the weight ratio of 20:66:112:2 exhibited a dissolution profile similar to that produced by the commercial prolonged release capsule. Furthermore, there were no significant differences in the AUC, Cmax, Tmax and MRT values between them in beagle dogs. Consequently, this tacrolimus-loaded prolonged release tablet might be bioequivalent to the tacrolimus-loaded commercial capsule. Copyright © 2013 Elsevier B.V. All rights reserved.

Preparation of resveratrol-loaded nanoporous silica materials with different structures

NASA Astrophysics Data System (ADS)

Popova, Margarita; Szegedi, Agnes; Mavrodinova, Vesselina; Novak Tušar, Natasa; Mihály, Judith; Klébert, Szilvia; Benbassat, Niko; Yoncheva, Krassimira

2014-11-01

Solid, nanoporous silica-based spherical mesoporous MCM-41 and KIL-2 with interparticle mesoporosity as well as nanosized zeolite BEA materials differing in morphology and pore size distribution, were used as carriers for the preparation of resveratrol-loaded delivery systems. Two preparation methods have been applied: (i) loading by mixing of resveratrol and mesoporous carrier in solid state and (ii) deposition in ethanol solution. The parent and the resveratrol loaded carriers were characterized by XRD, TEM, N2 physisorption, thermal analysis, and FT-IR spectroscopy. The influence of the support structure on the adsorption capacity and the release kinetics of this poorly soluble compound were investigated. Our results indicated that the chosen nanoporous silica supports are suitable for stabilization of trans-resveratrol and reveal controlled release and ability to protect the supported compound against degradation regardless of loading method. The solid-state dry mixing appears very effective for preparation of drug formulations composed of poorly soluble compound.

Anaerobic sludge digestion in the presence of lactobacillus additive

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

Ghosh, S.; Klass, D.L.

1980-01-01

A laboratory evaluation of a lactobacillus fermentation product was performed to study its effects as an additive on the anaerobic digestion of sewage sludge under conventional and overloaded high-rate conditions. The overloaded conditions were those experienced in commercial municipal digesters. It was concluded from this work that the use of the additive at low concentrations permits digester operation at least up to double the loading of untreated digesters and at higher methane yields and volatile solids reductions without affecting effluent quality. The additive also imparts iproved digester stability and rapid response to loading rate and detention time excursions and upsets.more » The beneficial effets of the additive observed in the laboratory remain to be established with other feeds such as biomass, and in large-scale commercial digestion tests that are now in progress.« less

Calibration of a dissolved-solids model for the Yampa River basin between Steamboat Springs and Maybell, northwestern Colorado

USGS Publications Warehouse

Parker, R.S.; Litke, D.W.

1987-01-01

The cumulative effects of changes in dissolved solids from a number of coal mines are needed to evaluate effects on downstream water use. A model for determining cumulative effects of streamflow, dissolved-solids concentration, and dissolved-solids load was calibrated for the Yampa River and its tributaries in northwestern Colorado. The model uses accounting principles. It establishes nodes on the stream system and sums water quantity and quality from node to node in the downstream direction. The model operates on a monthly time step for the study period that includes water years 1976 through 1981. Output is monthly mean streamflow, dissolved-solids concentration, and dissolved-solids load. Streamflow and dissolved-solids data from streamflow-gaging stations and other data-collection sites were used to define input data sets to initiate and to calibrate the model. The model was calibrated at four nodes and generally was within 10 percent of the observed values. The calibrated model can compute changes in dissolved-solids concentration or load resulting from the cumulative effects of new coal mines or the expansion of old coal mines in the Yampa River basin. (USGS)

Evaluation of Thin Kevlar-Epoxy Fabric Panels Subjected to Shear Loading

NASA Technical Reports Server (NTRS)

Baker, Donald J.

1996-01-01

The results of an analytical and experimental investigation of 4-ply Kevlar-49-epoxy panels loaded by in-plane shear are presented. Approximately one-half of the panels are thin-core sandwich panels and the other panels are solid-laminate panels. Selected panels were impacted with an aluminum sphere at a velocity of either 150 or 220 ft/sec. The strength of panels impacted at 150 ft/sec was not reduced when compared to the strength of the undamaged panels, but the strength of panels impacted at 220 ft/sec was reduced by 27 to 40 percent. Results are presented for panels that were cyclically loaded from a load less than the buckling load to a load in the postbuckling load range. The thin-core sandwich panels had a lower fatigue life than the solid panels. The residual strength of the solid and sandwich panels cycled more than one million cycles exceeded the baseline undamaged panel strengths. The effect of hysteresis in the response of the sandwich panels is not significant. Results of a nonlinear finite element analysis conducted for each panel design are presented.

Characteristics and trends of streamflow and dissolved solids in the upper Colorado River Basin, Arizona, Colorado, New Mexico, Utah, and Wyoming

USGS Publications Warehouse

Liebermann, Timothy D.; Mueller, David K.; Kircher, James E.; Choquette, Anne F.

1989-01-01

Annual and monthly concentrations and loads of dissolved solids and major constituents were estimated for 70 streamflow-gaging stations in the Upper Colorado River Basin. Trends in streamflow, dissolved-solids concentrations, and dissolved-solids loads were identified. Nonparametric trend-analysis techniques were used to determine step trends resulting from human activities upstream and long-term monotonic trends. Results were compared with physical characteristics of the basin and historical water-resource development in the basin to determine source areas of dissolved solids and possible cause of trends. Mean annual dissolved-solids concentration increases from less than 100 milligrams per liter in the headwater streams to more than 500 milligrams per liter in the outflow from the Upper Colorado River Basin. All the major tributaries that have high concentrations of dissolved solids are downstream from extensive areas of irrigated agriculture. However, irrigation predated the period of record for most sites and was not a factor in many identified trends. Significant annual trends were identified for 30 sites. Most of these trends were related to transbasin exports, changes in land use, salinity-control practices, or reservoir development. The primary factor affecting streamflow and dissolved-solids concentration and load has been the construction of large reservoirs. Reservoirs have decreased the seasonal and annual variability of streamflow and dissolved solids in streams that drain the Gunnison and San Juan River basins. Fontenelle and Flaming Gorge Reservoirs have increased the dissolved-solids load in the Green River because of dissolution of mineral salts from the bank material. The largest trends occurred downstream from Lake Powell. However, the period of record since the completion of filling was too short to estimate the long-term effects of that reservoir.

Evaluation of hybrid processes for nitrification by comparing MBBR/AS and IFAS configurations.

PubMed

Germain, E; Bancroft, L; Dawson, A; Hinrichs, C; Fricker, L; Pearce, P

2007-01-01

An integrated fixed-film activated sludge (IFAS) pilot plant and a moving bed biofilm reactor coupled with an activated sludge process (MBBR/AS) were operated under different temperatures, carbon loadings and solids retention times (SRTs). These two types of hybrid systems were compared, focusing on the nitrification capacity and the nitrifiers population of the media and suspended biomass alongside other process performances such as carbonaceous and total nitrogen (TN) removal rates. At high temperatures and loadings rates, both processes were fully nitrifying and achieved similarly high carbonaceous removal rates. However, under these conditions, the IFAS configuration performed better in terms of TN removal. Lower temperatures and carbon loadings led to lower carbonaceous removal rates for the MBBR/AS configuration, whereas the IFAS configuration was not affected. However, the nitrification capacity of the IFAS process decreased significantly under these conditions and the MBBR/AS process was more robust in terms of nitrification. Ammonia oxidising bacteria (AOB) and nitrite oxidising bacteria (NOB) population counts accurately reflected the changes in nitrification capacity. However, significantly less NOBs than AOBs were observed, without noticeable nitrite accumulation, suggesting that the characterisation method used was not as sensitive for NOBs and/or that the NOBs had a higher activity than the AOBs.

Influence of sampling frequency and load calculation methods on quantification of annual river nutrient and suspended solids loads.

PubMed

Elwan, Ahmed; Singh, Ranvir; Patterson, Maree; Roygard, Jon; Horne, Dave; Clothier, Brent; Jones, Geoffrey

2018-01-11

Better management of water quality in streams, rivers and lakes requires precise and accurate estimates of different contaminant loads. We assessed four sampling frequencies (2 days, weekly, fortnightly and monthly) and five load calculation methods (global mean (GM), rating curve (RC), ratio estimator (RE), flow-stratified (FS) and flow-weighted (FW)) to quantify loads of nitrate-nitrogen (NO 3 - -N), soluble inorganic nitrogen (SIN), total nitrogen (TN), dissolved reactive phosphorus (DRP), total phosphorus (TP) and total suspended solids (TSS), in the Manawatu River, New Zealand. The estimated annual river loads were compared to the reference 'true' loads, calculated using daily measurements of flow and water quality from May 2010 to April 2011, to quantify bias (i.e. accuracy) and root mean square error 'RMSE' (i.e. accuracy and precision). The GM method resulted into relatively higher RMSE values and a consistent negative bias (i.e. underestimation) in estimates of annual river loads across all sampling frequencies. The RC method resulted in the lowest RMSE for TN, TP and TSS at monthly sampling frequency. Yet, RC highly overestimated the loads for parameters that showed dilution effect such as NO 3 - -N and SIN. The FW and RE methods gave similar results, and there was no essential improvement in using RE over FW. In general, FW and RE performed better than FS in terms of bias, but FS performed slightly better than FW and RE in terms of RMSE for most of the water quality parameters (DRP, TP, TN and TSS) using a monthly sampling frequency. We found no significant decrease in RMSE values for estimates of NO 3 - N, SIN, TN and DRP loads when the sampling frequency was increased from monthly to fortnightly. The bias and RMSE values in estimates of TP and TSS loads (estimated by FW, RE and FS), however, showed a significant decrease in the case of weekly or 2-day sampling. This suggests potential for a higher sampling frequency during flow peaks for more precise and accurate estimates of annual river loads for TP and TSS, in the study river and other similar conditions.

The importance of the solids loading on confirming the dielectric nanosize dependence of BaTiO₃ powders by slurry method.

PubMed

Zhou, Wei; Nie, Yi Mei; Li, Shu Jing; Liang, Hai Yan

2013-01-01

The dielectric nanosize dependence of BaTiO₃ powders was investigated by the slurry method, where two series of BaTiO₃ slurries with 10 vol% and 30 vol% solids loadings were prepared as model samples. Applying the Bruggeman-Hanai equation, the high-frequency limiting permittivity (ε(h)) of the slurries was extracted from the dielectric spectra. The ε(h) of the 10 vol% slurry showed abnormal size independence in the range from 100 nm to 700 nm, and the ε(h) of the 30 vol% slurry exhibited good agreement with the previous prediction. Through analysing quantitatively the response of ε(h) to the changing permittivity of the powders under different solids loading, it was found that the ε h of the slurry with lower solids loading is more inclined to be interfered by the systematic and random errors. Furthermore, a high permittivity value was found in the BaTiO₃ powders with 50 nm particle size.

Optimization of Alkaline and Dilute Acid Pretreatment of Agave Bagasse by Response Surface Methodology.

PubMed

Ávila-Lara, Abimael I; Camberos-Flores, Jesus N; Mendoza-Pérez, Jorge A; Messina-Fernández, Sarah R; Saldaña-Duran, Claudia E; Jimenez-Ruiz, Edgar I; Sánchez-Herrera, Leticia M; Pérez-Pimienta, Jose A

2015-01-01

Utilization of lignocellulosic materials for the production of value-added chemicals or biofuels generally requires a pretreatment process to overcome the recalcitrance of the plant biomass for further enzymatic hydrolysis and fermentation stages. Two of the most employed pretreatment processes are the ones that used dilute acid (DA) and alkaline (AL) catalyst providing specific effects on the physicochemical structure of the biomass, such as high xylan and lignin removal for DA and AL, respectively. Another important effect that need to be studied is the use of a high solids pretreatment (≥15%) since offers many advantaged over lower solids loadings, including increased sugar and ethanol concentrations (in combination with a high solids saccharification), which will be reflected in lower capital costs; however, this data is currently limited. In this study, several variables, such as catalyst loading, retention time, and solids loading, were studied using response surface methodology (RSM) based on a factorial central composite design of DA and AL pretreatment on agave bagasse using a range of solids from 3 to 30% (w/w) to obtain optimal process conditions for each pretreatment. Subsequently enzymatic hydrolysis was performed using Novozymes Cellic CTec2 and HTec2 presented as total reducing sugar (TRS) yield. Pretreated biomass was characterized by wet-chemistry techniques and selected samples were analyzed by calorimetric techniques, and scanning electron/confocal fluorescent microscopy. RSM was also used to optimize the pretreatment conditions for maximum TRS yield. The optimum conditions were determined for AL pretreatment: 1.87% NaOH concentration, 50.3 min and 13.1% solids loading, whereas DA pretreatment: 2.1% acid concentration, 33.8 min and 8.5% solids loading.

Optimization of Alkaline and Dilute Acid Pretreatment of Agave Bagasse by Response Surface Methodology

PubMed Central

Ávila-Lara, Abimael I.; Camberos-Flores, Jesus N.; Mendoza-Pérez, Jorge A.; Messina-Fernández, Sarah R.; Saldaña-Duran, Claudia E.; Jimenez-Ruiz, Edgar I.; Sánchez-Herrera, Leticia M.; Pérez-Pimienta, Jose A.

2015-01-01

Utilization of lignocellulosic materials for the production of value-added chemicals or biofuels generally requires a pretreatment process to overcome the recalcitrance of the plant biomass for further enzymatic hydrolysis and fermentation stages. Two of the most employed pretreatment processes are the ones that used dilute acid (DA) and alkaline (AL) catalyst providing specific effects on the physicochemical structure of the biomass, such as high xylan and lignin removal for DA and AL, respectively. Another important effect that need to be studied is the use of a high solids pretreatment (≥15%) since offers many advantaged over lower solids loadings, including increased sugar and ethanol concentrations (in combination with a high solids saccharification), which will be reflected in lower capital costs; however, this data is currently limited. In this study, several variables, such as catalyst loading, retention time, and solids loading, were studied using response surface methodology (RSM) based on a factorial central composite design of DA and AL pretreatment on agave bagasse using a range of solids from 3 to 30% (w/w) to obtain optimal process conditions for each pretreatment. Subsequently enzymatic hydrolysis was performed using Novozymes Cellic CTec2 and HTec2 presented as total reducing sugar (TRS) yield. Pretreated biomass was characterized by wet-chemistry techniques and selected samples were analyzed by calorimetric techniques, and scanning electron/confocal fluorescent microscopy. RSM was also used to optimize the pretreatment conditions for maximum TRS yield. The optimum conditions were determined for AL pretreatment: 1.87% NaOH concentration, 50.3 min and 13.1% solids loading, whereas DA pretreatment: 2.1% acid concentration, 33.8 min and 8.5% solids loading. PMID:26442260

Anaerobic monodigestion of poultry manure: determination of operational parameters for CSTR.

PubMed

Chamy, R; León, C; Vivanco, E; Poirrier, P; Ramos, C

2012-01-01

In this work the anaerobic monodigestion for the treatment of turkey manure was evaluated, without its codigestion with another substrate. The effect of the organic loading rate (OLR) and the substrate concentration (high total solids (TS) concentration) or product concentration (high volatile fatty acids (VFA) and/or ammonia (NH(3)-N) concentrations) was studied. The results show that for a continuous stirred tank reactor (CSTR) operation, a maximum of 40 g/L of TS and 4.0 g/L of ammonium (NH(4)(+)) was required. In addition, the maximum organic loading rate (OLR) will not exceed 1.5 kg VS/m(3)d. Higher TS and NH(4)(+) concentrations and OLR lead to a reduction on the methane productivity and volatile solids (VS) removal. During the CSTR operation, a high alkalinity concentration (above 10 g/L CaCO(3)) was found; this situation allowed maintaining a constant and appropriate pH (close to 7.8), despite the VFA accumulation. In this sense, the alkalinity ratio (α) is a more appropriate control and monitoring parameter of the reactor operation compared to pH. Additionally, with this parameter a VS removal of 80% with a methane productivity of 0.50 m(3)(CH4)/m(3)(R)d is achieved.

A Comparison of Simple Rheological Parameters and Simulation Data for Zymomonas mobilis Fermentation Broths with High Substrate Loading in a 3-L Bioreactor

NASA Astrophysics Data System (ADS)

Um, Byung-Hwan; Hanley, Thomas R.

Traditionally, as much as 80% or more of an ethanol fermentation broth is water that must be removed. This mixture is not only costly to separate but also produces a large aqueous stream that must then be disposed of or recycled. Integrative approaches to water reduction include increasing the biomass concentration during fermentation. In this paper, experimental results are presented for the rheological behavior of high-solids enzymatic cellulose hydrolysis and ethanol fermentation for biomass conversion using Solka Floc as the model feedstock. The experimental determination of the viscosity, shear stress, and shear rate relationships of the 10 to 20% slurry concentrations with constant enzyme concentrations are performed with a variable speed rotational viscometer (2.0 to 200 rpm) at 40 °C. The viscosities of enzymatic suspension observed were in range of 0.0418 to 0.0144, 0.233 to 0.0348, and 0.292 to 0.0447 Pa s for shear rates up to 100 reciprocal seconds at 10, 15, and 20% initial solids (w/v), respectively. Computational fluid dynamics analysis of bioreactor mixing demonstrates the change in bioreactor mixing with increasing biomass concentration. The portion-loading method is shown to be effective for processing highsolids slurries.

Effect of Degeneration on Fluid–Solid Interaction within Intervertebral Disk Under Cyclic Loading – A Meta-Model Analysis of Finite Element Simulations

PubMed Central

Nikkhoo, Mohammad; Khalaf, Kinda; Kuo, Ya-Wen; Hsu, Yu-Chun; Haghpanahi, Mohammad; Parnianpour, Mohamad; Wang, Jaw-Lin

2015-01-01

The risk of low back pain resulted from cyclic loadings is greater than that resulted from prolonged static postures. Disk degeneration results in degradation of disk solid structures and decrease of water contents, which is caused by activation of matrix digestive enzymes. The mechanical responses resulted from internal solid–fluid interactions of degenerative disks to cyclic loadings are not well studied yet. The fluid–solid interactions in disks can be evaluated by mathematical models, especially the poroelastic finite element (FE) models. We developed a robust disk poroelastic FE model to analyze the effect of degeneration on solid–fluid interactions within disk subjected to cyclic loadings at different loading frequencies. A backward analysis combined with in vitro experiments was used to find the elastic modulus and hydraulic permeability of intact and enzyme-induced degenerated porcine disks. The results showed that the averaged peak-to-peak disk deformations during the in vitro cyclic tests were well fitted with limited FE simulations and a quadratic response surface regression for both disk groups. The results showed that higher loading frequency increased the intradiscal pressure, decreased the total fluid loss, and slightly increased the maximum axial stress within solid matrix. Enzyme-induced degeneration decreased the intradiscal pressure and total fluid loss, and barely changed the maximum axial stress within solid matrix. The increase of intradiscal pressure and total fluid loss with loading frequency was less sensitive after the frequency elevated to 0.1 Hz for the enzyme-induced degenerated disk. Based on this study, it is found that enzyme-induced degeneration decreases energy attenuation capability of disk, but less change the strength of disk. PMID:25674562

High-rate two-phase process for the anaerobic degradation of cellulose, employing rumen microorganisms for an efficient acidogenesis

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

Gijzen, H.J.; Zwart, K.B.; Verhagen, F.J.M.

1988-04-05

A novel two-stage anaerobic process for the microbial conversion of cellulose into biogas has been developed. In the first phase, a mixed population of rumen bacteria and ciliates was used in the hydrolysis and fermentation of cellulose. The volatile fatty acids (VFA) produced in this acidogenic reactor were subsequently converted into biogas in a UASB-type methanogenic reactor. A stepwise increase of the loading rate from 11.9 to 25.8 g volatile solids/L reactor volume/day (g VS/L/day) did not affect the degradation efficiency in the acidogenic reactor, whereas the methanogenic reactor appeared to be overloaded at the highest loading rate. Cellulose digestionmore » was almost complete at all loading rates applied. The two-stage anaerobic process was also tested with a closed fluid circuit. In this instance total methane production was 0.438 L CH/sub 4//g VS added, which is equivalent to 98% of the theoretical value. The application of rumen microorganisms in combination with a high-rate methane reactor is proposed as a means of efficient anaerobic degradation of cellulosic residues to methane. Because this newly developed two-phase system is based on processes and microorganisms from the ruminant, it will be referred to as Rumen Derived Anaerobic Digestion (RUDAD)-process.« less

Development and Characterization of a High-Solids Deacetylation Process

DOE PAGES

Shekiro, III, Joseph; Chen, Xiaowen; Smith, Holly; ...

2016-05-20

Dilute-acid pretreatment has proven to be a robust means of converting herbaceous feedstock to fermentable sugars. However, it also releases acetic acid, a known fermentation inhibitor, from acetyl groups present in the biomass. A mild, dilute alkaline extraction stage was implemented prior to acid pretreatment to separate acetic acid from the hydrolysate sugar stream. This step, termed deacetylation, improved the glucose and xylose yields from enzymatic hydrolysis and ethanol yields from fermentation of the sugars relative to the control experiments using dilute-acid pretreatment of native corn stover without deacetylation. While promising, deacetylation as it was historically practiced is conducted atmore » low solids loadings, and at fixed conditions. Thus, many questions have been left unanswered, including the relationship between sodium hydroxide and solids loading, and acetate and xylan solubilization, as well as the impact of temperature and residence time on the process efficacy. A central composite experiment was designed to evaluate the impact of solids loading, sodium hydroxide loading, reaction time and temperature during deacetylation on the acetate and xylan solubilization of corn stover. Using the ANOVA test, it became apparent that neither of the responses was significantly impacted by the solids loading, while the reaction time was a minor factor - the responses were largely driven by reaction temperature and the sodium hydroxide loading. Based on the results, we successfully demonstrated the ability to transition the low-solids (10 % w/w) deacetylation process to a higher-solids process (30 % w/w) with minimal impact on the ability to extract acetate from biomass. Conditions were selected to minimize xylose loss during deacetylation, while also removing 70 % of acetyl groups. The impact of selected conditions on the enzymatic hydrolysis and fermentation was further investigated. In conclusion, evaluation of the whole-process impact demonstrated that despite the upfront reduction in carbohydrate loss during deacetylation, the overall process sugar yields were depressed by the high-solids, low alkali process relative to the historical control. Consequently, ethanol titers were reduced, though strong fermentation performance was still observed, indicating that 70 % acetate removal is sufficient to depress acetic acid concentrations to a level that does not substantially inhibit ethanol fermentation by rZymomo nas.« less

Dry anaerobic digestion of high solids content dairy manure at high organic loading rates in psychrophilic sequence batch reactor.

PubMed

Massé, Daniel I; Saady, Noori M Cata

2015-05-01

Cow manure with bedding is renewable organic biomass available around the year on dairy farms. Developing efficient and cost-effective psychrophilic dry anaerobic digestion (PDAD) processes could contribute to solving farm-related environmental, energy, and manure management problems in cold-climate regions. This study was to increase the organic loading rate (OLR), fed to a novel psychrophilic (20 °C) dry anaerobic digestion of 27% total solid dairy manure (cow feces and wheat straw) in sequence batch reactor (PDAD-SBR), by 133 to 160%. The PDAD-SBR process operated at treatment cycle length of 21 days and OLR of 7.0 and 8.0 g total chemical oxygen demand (TCOD) kg(-1) inoculum day(-1) (5.2 ± 0.1 and 5.8 ± 0.0 g volatile solids (VS) kg(-1) inoculum day(-1)) for four successive cycles (84 days) produced average specific methane yields (SMYs) of 147.1 ± 17.2 and 143.2 ± 11.7 normalized liters (NL) CH4 kg(-1) VS fed, respectively. PDAD of cow feces and wheat straw is possible with VS-based inoculum-to-substrate ratio of 1.45 at OLR of 8.0 g TCOD kg(-1) inoculum day(-1). Hydrolysis was the limiting step reaction. The VS removal averaged around 57.4 ± 0.5 and 60.5 ± 5.7% at OLR 7.0 and 8.0 g TCOD kg(-1) inoculum day(-1), respectively.

Solid dispersions of Myricetin with enhanced solubility: Formulation, characterization and crystal structure of stability-impeding Myricetin monohydrate crystals

NASA Astrophysics Data System (ADS)

Mureşan-Pop, M.; Pop, M. M.; Borodi, G.; Todea, M.; Nagy-Simon, T.; Simon, S.

2017-08-01

Three solid dispersion forms of Myricetin combined with the Polyvinylpyrrolidone were successfully prepared by spray drying method, and characterized by X-ray powder diffraction, thermal analysis, infrared spectroscopy and optical microscopy. Zeta potential measurements provided indications on solid dispersions stability in aqueous suspension related to their storage at elevated temperature and relative humidity, which depends on the Myricetin load. By increase of Myricetin load, the stability of the solid dispersion is impeded due to growth of Myricetin monohydrate crystals. The amorphous dispersions with 10% and 50% Myricetin load are stable and, compared to pure Myricetin, their aqueous solubility is enhanced by a factor of 47 and 13, respectively. The dispersion with 80% Myricetin load is unstable on storage, and this behavior acts in conjunction with the development of Myricetin monohydrate crystals. Single-crystal X-ray diffraction results obtained for Myricetin monohydrate reveal a structure of an infinite 2D network of hydrogen-bonded molecules involving all six hydroxyl groups of Myricetin. The water molecules are positioned in between the infinite chains, and contribute via H-bonds to robust crystal packing. The calculated needle-like morphology of monohydrate form is in agreement with the optical microscopy results. The study shows that the solid amorphous dispersions with up to 50% Myricetin load are a viable option for achieving substantial solubility improvement of Myricetin, and supports their potential use in pharmaceutical applications.

[A study on the relationship between point mutation in pre-core region G1896A of hepatitis B virus and safety of breast feeding].

PubMed

Lu, Yin-ping; Cao, Wei; Hong, Mei; Zhu, Jian-fang; Liu, Zhao; Yang, Dong-liang

2008-10-01

To investigate the relationship between pre-core G1896A point mutation of hepatitis B virus (HBV) and safety of breast feeding. Serum and breast milk samples were collected from 62 pregnant women of HBV DNA positive/HBeAg negative. PCR-solid phase hybridization was used to detect the point mutation in pre-core region G1896A of HBV from pregnant women, and HBV DNA loads in sera and breast milk were determined by fluorescence quantitative PCR (FQ-PCR). The prevalence of point mutation was 61.3% (38/62) in 62 pregnant women with HBsAg positive/HBeAg negative. The positive rate of HBV DNA in breast milk of group with point mutation (28.9%) was similar to that of group without mutation (29.2%, chi2=0.0003, P>0.05). However, The positive rate of HBV DNA in breast milk of group with high HBV loads (56.0%) was significantly higher than that of group with low HBV loads (10.8%, chi2=14.79, P<0.01). The point mutation in pre-core region G1896A of HBV dose not affect the positive rate of HBV DNA in breast milk and higher HBV DNA loads in serum of pregnant women might increase the risk of mother-infant transmission.

Fourth-power law structure of the shock wave fronts in metals and ceramics

NASA Astrophysics Data System (ADS)

Bayandin, Yuriy; Naimark, Oleg; Saveleva, Natalia

2017-06-01

The plate impact experiments were performed for solids during last fifty years. It was established that the dependence between the strain rate and the shock wave amplitude for metals and ceramics expressed by a fourth-power law. Present study is focused on the theoretical investigation and numerical simulation of plane shock wave propagation in metals and ceramics. Statistically based constitutive model of solid with defects (microcracks and microshears) was developed to provide the relation between damage induced mechanisms of structural relaxation, thermally activated plastic flow and material reactions for extreme loading conditions. Original approach based on the wide range constitutive equations was proposed for the numerical simulation of multiscale damage-failure transition mechanisms and plane shock wave propagation in solids with defects in the range of strain rate 103 -108s-1 . It was shown that mechanisms of plastic relaxation and damage-failure transitions are linked to the multiscale kinetics of defects leading to the self-similar nature of shock wave fronts in metals and ceramics. The work was supported by the Russian Science Foundation (Project No. 14-19-01173).

Developing a master plan for hospital solid waste management: A case study

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

Karamouz, Mohammad; Zahraie, Banafsheh; Kerachian, Reza

2007-07-01

Disposal of about 1750 tons of solid wastes per day is the result of a rapid population growth in the province of Khuzestan in the south west of Iran. Most of these wastes, especially hospital solid wastes which have contributed to the pollution of the environment in the study area, are not properly managed considering environmental standards and regulations. In this paper, the framework of a master plan for managing hospital solid wastes is proposed considering different criteria which are usually used for evaluating the pollution of hospital solid waste loads. The effectiveness of the management schemes is also evaluated.more » In order to rank the hospitals and determine the share of each hospital in the total hospital solid waste pollution load, a multiple criteria decision making technique, namely analytical hierarchy process (AHP), is used. A set of projects are proposed for solid waste pollution control and reduction in the proposed framework. It is partially applied for hospital solid waste management in the province of Khuzestan, Iran. The results have shown that the hospitals located near the capital city of the province, Ahvaz, produce more than 43% of the total hospital solid waste pollution load of the province. The results have also shown the importance of improving management techniques rather than building new facilities. The proposed methodology is used to formulate a master plan for hospital solid waste management.« less

Methane production by anaerobic digestion of water hyacinth (Eichhornia crassipes)

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

Klass, D.L.; Ghosh, S.

1980-01-01

Water hyacinth under conventional high-rate digestion conditions exhibited higher CH4 yields and energy recovery efficiencies when grown in sewage-fed lagoons than when grown in a fresh water pond. Mesophilic digestion provided the highest recovery of feed energy in the product gas as CH4, while thermophilic digestion, when operated at sufficiently high loading rates and reduced detention times, gave the highest specific CH4 production rates. CH4 yields, volatile solids reduction, and energy recovery as CH4 from the sewage-grown water hyacinth were in the same range as those observed for other biomass substrates when digested under similar conditions.

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

Renlund, Anita Mariana; Tappan, Alexander Smith; Miller, Jill C.

The HMX {beta}-{delta} solid-solid phase transition, which occurs as HMX is heated near 170 C, is linked to increased reactivity and sensitivity to initiation. Thermally damaged energetic materials (EMs) containing HMX therefore may present a safety concern. Information about the phase transition is vital to predictive safety models for HMX and HMX-containing EMs. We report work on monitoring the phase transition with real-time Raman spectroscopy aimed towards obtaining a better understanding of physical properties of HMX through the phase transition. HMX samples were confined in a cell of minimal free volume in a displacement-controlled or load-controlled arrangement. The cell wasmore » heated and then cooled at controlled rates while real-time Raman spectroscopic measurements were performed. Raman spectroscopy provides a clear distinction between the phases of HMX because the vibrational transitions of the molecule change with conformational changes associated with the phase transition. Temperature of phase transition versus load data are presented for both the heating and cooling cycles in the load-controlled apparatus, and general trends are discussed. A weak dependence of the temperature of phase transition on load was discovered during the heating cycle, with higher loads causing the phase transition to occur at a higher temperature. This was especially true in the temperature of completion of phase transition data as opposed to the temperature of onset of phase transition data. A stronger dependence on load was observed in the cooling cycle, with higher loads causing the reverse phase transitions to occur at a higher cooling temperature. Also, higher loads tended to cause the phase transition to occur over a longer period of time in the heating cycle and over a shorter period of time in the cooling cycle. All three of the pure HMX phases ({alpha}, {beta} and {delta}) were detected on cooling of the heated samples, either in pure form or as a mixture.« less

Updated estimates of long-term average dissolved-solids loading in streams and rivers of the Upper Colorado River Basin

USGS Publications Warehouse

Tillman, Fred D.; Anning, David W.

2014-01-01

The Colorado River and its tributaries supply water to more than 35 million people in the United States and 3 million people in Mexico, irrigating over 4.5 million acres of farmland, and annually generating about 12 billion kilowatt hours of hydroelectric power. The Upper Colorado River Basin, part of the Colorado River Basin, encompasses more than 110,000 mi2 and is the source of much of more than 9 million tons of dissolved solids that annually flows past the Hoover Dam. High dissolved-solids concentrations in the river are the cause of substantial economic damages to users, primarily in reduced agricultural crop yields and corrosion, with damages estimated to be greater than 300 million dollars annually. In 1974, the Colorado River Basin Salinity Control Act created the Colorado River Basin Salinity Control Program to investigate and implement a broad range of salinity control measures. A 2009 study by the U.S. Geological Survey, supported by the Salinity Control Program, used the Spatially Referenced Regressions on Watershed Attributes surface-water quality model to examine dissolved-solids supply and transport within the Upper Colorado River Basin. Dissolved-solids loads developed for 218 monitoring sites were used to calibrate the 2009 Upper Colorado River Basin Spatially Referenced Regressions on Watershed Attributes dissolved-solids model. This study updates and develops new dissolved-solids loading estimates for 323 Upper Colorado River Basin monitoring sites using streamflow and dissolved-solids concentration data through 2012, to support a planned Spatially Referenced Regressions on Watershed Attributes modeling effort that will investigate the contributions to dissolved-solids loads from irrigation and rangeland practices.

Formulation optimization of aprepitant microemulsion-loaded silicated corn fiber gum particles for enhanced bioavailability.

PubMed

Kamboj, Sunil; Rana, Vikas

2016-08-01

The present investigation was aimed at development of silicate corn fiber gum (SCFG) particles as superior solid carrier for the preparation of Aprepitant (APT)-loaded self-emulsifying powder (SEP) system. 2(4) D-optimal mixture design with three level process variables was employed to develop SCFG particles, utilizing flow descriptors and hydrophobicity descriptors as response variables. The results indicated that blending of CFG (51.4% w/w) and magnesium silicate (MS) (48.6% w/w) using freeze-drying technique was found to have highest desirability (0.904). The developed SEP showed highest oil desorbing capacity, low self-emulsification time and highest drug content. It was observed that SCFG-SEP (F2 formulation) showed lowest PDI (0.2445 ± 0.03) as well as smallest particle size (127 ± 5.8 nm). The droplets were uniform and maintain their integrity after reconstitution (TEM analysis). Furthermore, APT-loaded SEP showed enhanced in vitro dissolution (4 folds) and ex vivo performance (7-fold enhanced Papp) as compared to pure APT. Furthermore, in vivo pharmacokinetic study showed that significant enhancement (p > 0.05) in Cmax was evident with APT-loaded F2 (SCFG-SEP) (1.93-fold) and F4 (Aerosil 200-SEP) (1.58-fold). The data also suggested increase in absorption rate when APT incorporated into SCFG-SEP. Thus, findings pointed toward enhanced bioavailability of APT when loaded into SCFG particles. Overall, the developed SCFG particles could be considered as a better alternative to already available solid carrier(s).

Sugar loss and enzyme inhibition due to oligosaccharides accumulation during high solids-loading enzymatic hydrolysis

USDA-ARS?s Scientific Manuscript database

Oligosaccharide accumulation occurs during high solid loading enzymatic hydrolysis of corn stover (CS) irrespective of using different pretreated corn stover (dilute acid: DA, ionic liquids: IL, ammonia fiber expansion: AFEX and extractive ammonia: EA). The methodology for large-scale separation of ...

Solid-state power controller

NASA Technical Reports Server (NTRS)

Fox, D. A.; Fullemann, J. S.

1980-01-01

Compact, solid state, electric-power controller switches power on and off at remote load, limits current drawn by load, and shuts off (with 2- to 3- second trip time) in case of short circuit. Lightweight efficient hybrid unit operates at 28 volts dc and at maximum currents of from 3 to 2 amperes.

Treatment of thin stillage in a high-rate anaerobic fluidized bed bioreactor (AFBR).

PubMed

Andalib, Mehran; Hafez, Hisham; Elbeshbishy, Elsayed; Nakhla, George; Zhu, Jesse

2012-10-01

The primary objective of this work was to investigate the treatability of thin stillage as a by-product of bioethanol production plants using an anaerobic fluidized bed bioreactor (AFBR) employing zeolite with average diameter of (d(m)) of 425-610 μm and specific surface area (SSA) of 26.5m(2)/g as the carrier media. Despite the very high strength of thin stillage with chemical oxygen demand of 130,000 mg TCOD/L and suspended solids of 47,000 mg TSS/L, the AFBR showed up to 88% TCOD and 78% TSS removal at very high organic and solids loading rates (OLR and SLR) of 29 kg COD/m(3)d and 10.5 kg TSS/m(3)d respectively and hydraulic retention time (HRT) of 3.5 days. Methane production rates of up to 160 L/d at the steady state equivalent to 40 L(CH4)/L(thin stillage)d and biogas production rate per reactor volume of 15.8L(gas)/L(reactor)d were achieved. Copyright © 2012 Elsevier Ltd. All rights reserved.

Development of free-flowing peppermint essential oil-loaded hollow solid lipid micro- and nanoparticles via atomization with carbon dioxide.

PubMed

Yang, Junsi; Ciftci, Ozan Nazim

2016-09-01

The main objective of this study was to overcome the issues related to the volatility and strong smell that limit the efficient utilization of essential oils as "natural" antimicrobials in the food industry. Peppermint essential oil-loaded hollow solid lipid micro- and nanoparticles were successfully formed using a novel "green" method based on atomization of CO 2 -expanded lipid mixture. The highest essential oil loading efficiency (47.5%) was achieved at 50% initial essential oil concentration at 200bar expansion pressure and 50μm nozzle diameter, whereas there was no significant difference between the loading efficiencies (35%-39%) at 5%, 7%, 10%, and 20% initial essential oil concentrations (p>0.05). Particles generated at all initial essential oil concentrations were spherical but increasing the initial essential oil concentration to 20% and 50% generated a less smooth particle surface. After 4weeks of storage, 61.2%, 42.5%, 0.2%, and 2.0% of the loaded essential oil was released from the particles formed at 5%, 10%, 20%, and 50% initial essential oil concentrations, respectively. This innovative simple and clean process is able to form spherical hollow micro- and nanoparticles loaded with essential oil that can be used as food grade antimicrobials. These novel hollow solid lipid micro- and nanoparticles are alternatives to the solid lipid nanoparticles, and overcome the issues associated with the solid lipid nanoparticles. The dry free-flowing products make the handling and storage more convenient, and the simple and clean process makes the scaling up more feasible. Copyright © 2016 Elsevier Ltd. All rights reserved.

Co-production of bio-ethanol, xylonic acid and slow-release nitrogen fertilizer from low-cost straw pulping solid residue.

PubMed

Huang, Chen; Ragauskas, Arthur J; Wu, Xinxing; Huang, Yang; Zhou, Xuelian; He, Juan; Huang, Caoxing; Lai, Chenhuan; Li, Xin; Yong, Qiang

2018-02-01

A novel bio-refinery sequence yielding varieties of co-products was developed using straw pulping solid residue. This process utilizes neutral sulfite pretreatment which under optimal conditions (160 °C and 3% (w/v) sulfite charge) provides 64.3% delignification while retaining 90% of cellulose and 67.3% of xylan. The pretreated solids exhibited excellent enzymatic digestibility, with saccharification yields of 86.9% and 81.1% for cellulose and xylan, respectively. After pretreatment, the process of semi-simultaneous saccharification and fermentation (S-SSF) and bio-catalysis was investigated. The results revealed that decreased ethanol yields were achieved when solid loading increased from 5% to 30%. An acceptable ethanol yield of 76.8% was obtained at 20% solid loading. After fermentation, bio-catalysis of xylose remaining in fermentation broth resulted in near 100% xylonic acid (XA) yield at varied solid loadings. To complete the co-product portfolio, oxidation ammoniation of the dissolved lignin successfully transformed it into biodegradable slow-release nitrogen fertilizer with excellent agricultural properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

Design and operation of an anaerobic digester for waste management and fuel generation during long term lunar mission

NASA Astrophysics Data System (ADS)

Dhoble, Abhishek S.; Pullammanappallil, Pratap C.

2014-10-01

Waste treatment and management for manned long term exploratory missions to moon will be a challenge due to longer mission duration. The present study investigated appropriate digester technologies that could be used on the base. The effect of stirring, operation temperature, organic loading rate and reactor design on the methane production rate and methane yield was studied. For the same duration of digestion, the unmixed digester produced 20-50% more methane than mixed system. Two-stage design which separated the soluble components from the solids and treated them separately had more rapid kinetics than one stage system, producing the target methane potential in one-half the retention time than the one stage system. The two stage system degraded 6% more solids than the single stage system. The two stage design formed the basis of a prototype digester sized for a four-person crew during one year exploratory lunar mission.

Modeling dynamic beta-gamma polymorphic transition in Tin

NASA Astrophysics Data System (ADS)

Chauvin, Camille; Montheillet, Frank; Petit, Jacques; CEA Gramat Collaboration; EMSE Collaboration

2015-06-01

Solid-solid phase transitions in metals have been studied by shock waves techniques for many decades. Recent experiments have investigated the transition during isentropic compression experiments and shock-wave compression and have highlighted the strong influence of the loading rate on the transition. Complementary data obtained with velocity and temperature measurements around the polymorphic transition beta-gamma of Tin on gas gun experiments have displayed the importance of the kinetics of the transition. But, even though this phenomenon is known, modeling the kinetic remains complex and based on empirical formulations. A multiphase EOS is available in our 1D Lagrangian code Unidim. We propose to present the influence of various kinetic laws (either empirical or involving nucleation and growth mechanisms) and their parameters (Gibbs free energy, temperature, pressure) on the transformation rate. We compare experimental and calculated velocities and temperature profiles and we underline the effects of the empirical parameters of these models.

Preparation and in Vivo Evaluation of a Dutasteride-Loaded Solid-Supersaturatable Self-Microemulsifying Drug Delivery System

PubMed Central

Kim, Min-Soo; Ha, Eun-Sol; Choo, Gwang-Ho; Baek, In-Hwan

2015-01-01

The purpose of this study was to prepare a dutasteride-loaded solid-supersaturatable self-microemulsifying drug delivery system (SMEDDS) using hydrophilic additives with high oral bioavailability, and to determine if there was a correlation between the in vitro dissolution data and the in vivo pharmacokinetic parameters of this delivery system in rats. A dutasteride-loaded solid-supersaturatable SMEDDS was generated by adsorption of liquid SMEDDS onto Aerosil 200 colloidal silica using a spray drying process. The dissolution and oral absorption of dutasteride from solid SMEDDS significantly increased after the addition of hydroxypropylmethyl cellulose (HPMC) or Soluplus. Solid SMEDDS/Aerosil 200/Soluplus microparticles had higher oral bioavailability with 6.8- and 5.0-fold higher peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) values, respectively, than that of the equivalent physical mixture. A linear correlation between in vitro dissolution efficiency and in vivo pharmacokinetic parameters was demonstrated for both AUC and Cmax values. Therefore, the preparation of a solid-supersaturatable SMEDDS with HPMC or Soluplus could be a promising formulation strategy to develop novel solid dosage forms of dutasteride. PMID:25984604

Ultrastructural changes of sheep cumulus-oocyte complexes following different methods of vitrification.

PubMed

Ebrahimi, Bita; Valojerdi, Mojtaba Rezazadeh; Eftekhari-Yazdi, Poopak; Baharvand, Hossein

2012-05-01

To determine the ultrastructural changes of sheep cumulus-oocyte complexes (COCs) following different methods of vitrification, good quality isolated COCs (GV stage) were randomly divided into the non-vitrified control, conventional straw, cryotop and solid surface vitrification groups. In both conventional and cryotop methods, vitrified COCs were respectively loaded by conventional straws and cryotops, and then plunged directly into liquid nitrogen (LN2); whereas in the solid surface group, vitrified COCs were first loaded by cryotops and then cooled before plunging into LN2. Post-warming survivability and ultrastructural changes of healthy COCs in the cryotop group especially in comparison with the conventional group revealed better viability rate and good preservation of the ooplasm organization. However in all vitrification groups except the cryotop group, mitochondria were clumped. Solely in the conventional straw group, the mitochondria showed different densities and were extremely distended. Moreover in the latter group, plenty of large irregular connected vesicles in the ooplasm were observed and in some parts their membrane ruptured. Also, in the conventional and solid surface vitrification groups, cumulus cells projections became retracted from the zona pellucida in some parts. In conclusion, the cryotop vitrification method as compared with other methods seems to have a good post-warming survivability and shows less deleterious effects on the ultrastructure of healthy vitrified-warmed sheep COCs.

Characterization of Thermal and Mechanical Impact on Aluminum Honeycomb Structures

NASA Technical Reports Server (NTRS)

Robinson, Christen M.

2013-01-01

This study supports NASA Kennedy Space Center's research in the area of intelligent thermal management systems and multifunctional thermal systems. This project addresses the evaluation of the mechanical and thermal properties of metallic cellular solid (MCS) materials; those that are lightweight; high strength, tunable, multifunctional and affordable. A portion of the work includes understanding the mechanical properties of honeycomb structured cellular solids upon impact testing under ambient, water-immersed, liquid nitrogen-cooled, and liquid nitrogen-immersed conditions. Additionally, this study will address characterization techniques of the aluminum honeycomb's ability to resist multiple high-rate loadings or impacts in varying environmental conditions, using various techniques for the quantitative and qualitative determination for commercial applicability.

Solution behavior of PVP-VA and HPMC-AS-based amorphous solid dispersions and their bioavailability implications.

PubMed

Qian, Feng; Wang, Jennifer; Hartley, Ruiling; Tao, Jing; Haddadin, Raja; Mathias, Neil; Hussain, Munir

2012-10-01

To identify the mechanism behind the unexpected bio-performance of two amorphous solid dispersions: BMS-A/PVP-VA and BMS-A/HPMC-AS. Solubility of crystalline BMS-A in PVP-VA and HPMC-AS was measured by DSC. Drug-polymer interaction parameters were obtained by Flory-Huggins model fitting. Drug dissolution kinetics of spray-dried dispersions were studied under sink and non-sink conditions. BMS-A supersaturation was studied in the presence of pre-dissolved PVP-VA and HPMC-AS. Potency and crystallinity of undissolved solid dispersions were determined by HPLC and DSC. Polymer dissolution kinetics were obtained by mass balance calculation. Bioavailability of solid dispersions was assessed in dogs. In solid state, both polymers are miscible with BMS-A, while PVP-VA solublizes the drug better. BMS-A dissolves similarly from both solid dispersions in vitro regardless of dissolution method, while the HPMC-AS dispersion performed much better in vivo. At the same concentration, HPMC-AS is more effective in prolonging BMS-A supersaturation; this effect was negated by the slow dissolution rate of HPMC-AS. Further study revealed that fast PVP-VA dissolution resulted in elevated drug loading in undissolved dispersions and facilitated drug recrystallization before complete release. In contrast, the hydrophobicity and slower HPMC-AS dissolution prevented BMS-A recrystallization within the HPMC-AS matrix for >24 h. The lower bioavailability of PVP-VA dispersion was attributed to BMS-A recrystallization within the undissolved dispersion, due to hydrophilicity and fast PVP-VA dissolution rate. Polymer selection for solid dispersion development has significant impact on in vivo performance besides physical stability.

Orally Disintegrating Tablets Containing Melt Extruded Amorphous Solid Dispersion of Tacrolimus for Dissolution Enhancement.

PubMed

Ponnammal, Poovizhi; Kanaujia, Parijat; Yani, Yin; Ng, Wai Kiong; Tan, Reginald B H

2018-03-16

In order to improve the aqueous solubility and dissolution of Tacrolimus (TAC), amorphous solid dispersions of TAC were prepared by hot melt extrusion with three hydrophilic polymers, Polyvinylpyrrolidone vinyl acetate (PVP VA64), Soluplus ® and Hydroxypropyl Cellulose (HPC), at a drug loading of 10% w / w . Molecular modeling was used to determine the miscibility of the drug with the carrier polymers by calculating the Hansen Solubility Parameters. Powder X-ray diffraction and differential scanning calorimetry (DSC) studies of powdered solid dispersions revealed the conversion of crystalline TAC to amorphous form. Fourier transform Infrared (FTIR) spectroscopy results indicated formation of hydrogen bond between TAC and polymers leading to stabilization of TAC in amorphous form. The extrudates were found to be stable under accelerated storage conditions for 3 months with no re-crystallization, indicating that hot melt extrusion is suitable for producing stable amorphous solid dispersions of TAC in PVP VA64, Soluplus ® and HPC. Stable solid dispersions of amorphous TAC exhibited higher dissolution rate, with the solid dispersions releasing more than 80% drug in 15 min compared to the crystalline drug giving 5% drug release in two hours. These stable solid dispersions were incorporated into orally-disintegrating tablets in which the solid dispersion retained its solubility, dissolution and stability advantage.

Orally Disintegrating Tablets Containing Melt Extruded Amorphous Solid Dispersion of Tacrolimus for Dissolution Enhancement

PubMed Central

Ponnammal, Poovizhi; Kanaujia, Parijat; Ng, Wai Kiong; Tan, Reginald B. H.

2018-01-01

In order to improve the aqueous solubility and dissolution of Tacrolimus (TAC), amorphous solid dispersions of TAC were prepared by hot melt extrusion with three hydrophilic polymers, Polyvinylpyrrolidone vinyl acetate (PVP VA64), Soluplus® and Hydroxypropyl Cellulose (HPC), at a drug loading of 10% w/w. Molecular modeling was used to determine the miscibility of the drug with the carrier polymers by calculating the Hansen Solubility Parameters. Powder X-ray diffraction and differential scanning calorimetry (DSC) studies of powdered solid dispersions revealed the conversion of crystalline TAC to amorphous form. Fourier transform Infrared (FTIR) spectroscopy results indicated formation of hydrogen bond between TAC and polymers leading to stabilization of TAC in amorphous form. The extrudates were found to be stable under accelerated storage conditions for 3 months with no re-crystallization, indicating that hot melt extrusion is suitable for producing stable amorphous solid dispersions of TAC in PVP VA64, Soluplus® and HPC. Stable solid dispersions of amorphous TAC exhibited higher dissolution rate, with the solid dispersions releasing more than 80% drug in 15 min compared to the crystalline drug giving 5% drug release in two hours. These stable solid dispersions were incorporated into orally-disintegrating tablets in which the solid dispersion retained its solubility, dissolution and stability advantage. PMID:29547585

Solids, organic load and nutrient concentration reductions in swine waste slurry using a polyacrylamide (PAM)-aided solids flocculation treatment.

PubMed

Walker, Paul; Kelley, Tim

2003-11-01

Increased swine production results in concentration of wastes generated within a limited geographical area, which may lead to land application rates exceeding the local or regional assimilatory capacity. This may result in pollutant transfer through surface water or soil-groundwater systems, environmental degradation, and/or odor concerns. Existing swine waste pit storage and lagoon treatment technologies may be inadequate to store or treat waste prior to land application without these concerns resulting. Efficient swine waste solids separation may reduce environmental health concerns and generate a value-added bioresource (solids). This study evaluated the efficiency of a polyacrylamide (PAM) flocculant-aided solids separation treatment to reduce pollution indicator concentrations in raw (untreated) swine waste slurry. Swine waste slurry solids separation efficiency through gravity settling (sedimentation) was evaluated before and after the addition of a proprietary polymeric (PAM) flocculant. Results indicated that polymer amendments at concentrations of 62.5-750 mg/l improved slurry solids separation efficiency and significantly reduced concentrations of other associated aquatic pollution indicators in a majority of analyses conducted (33 of 50 total analyses conducted). Results also suggested that PAM-aided solids separation from swine waste slurry might facilitate further treatment and/or disposal and therefore reduce associated environmental degradation potential.

Nanostructured lipid carriers (NLCs) versus solid lipid nanoparticles (SLNs) for topical delivery of meloxicam.

PubMed

Khalil, Rawia M; Abd-Elbary, A; Kassem, Mahfoz A; Ghorab, Mamdouh M; Basha, Mona

2014-05-01

The aim of this study was to develop nanostructured lipid carriers (NLCs) as well as solid lipid nanoparticles (SLNs) and evaluate their potential in the topical delivery of meloxicam (MLX). The effect of various compositional variations on their physicochemical properties was investigated. Furthermore, MLX-loaded lipid nanoparticles-based hydrogels were formulated and the gels were evaluated as vehicles for topical application. The results showed that NLC and SLN dispersions had spherical shapes with an average size between 215 and 430 nm. High entrapment efficiency was obtained ranging from 61.94 to 90.38% with negatively charged zeta potential in the range of -19.1 to -25.7 mV. The release profiles of all formulations exhibited sustained release characteristics over 48 h and the release rates increased as the amount of liquid lipid in lipid core increased. Finally, Precirol NLC with 50% Miglyol® 812 and its corresponding SLN were incorporated in hydrogels. The gels showed adequate pH, non-Newtonian flow with shear-thinning behavior and controlled release profiles. The biological evaluation revealed that MLX-loaded NLC gel showed more pronounced effect compared to MLX-loaded SLN gel. It can be concluded that lipid nanoparticles represent promising particulate carriers for topical application.

Formulation development and process analysis of drug-loaded filaments manufactured via hot-melt extrusion for 3D-printing of medicines.

PubMed

Korte, Carolin; Quodbach, Julian

2018-02-09

Three dimensional(3D)-printing via fused deposition modeling (FDM) allows the production of individualized solid dosage forms. However, for bringing this benefit to the patient, active pharmaceutical ingredient (API)-loaded filaments of pharmaceutical grade excipients are necessary as feedstock and have to be produced industrially. As large-scale production of API-loaded filaments has not been described in literature, this study presents a development of 3D-printable filaments, which can continuously be produced via hot-melt extrusion. Further, a combination of testing methods for mechanical resilience of filaments was applied to improve the prediction of their printability. Eudragit RL was chosen as a sustained release polymer and theophylline (30%) as thermally stable model drug. Stearic acid (7%) and polyethylene glycol 4000 (10%), were evaluated as suitable plasticizers for producing 3D-printable filaments. The two formulations were printed into solid dosage forms and analyzed regarding their dissolution profiles. This revealed that stearic acid maintained sustained release properties of the matrix whereas polyethylene glycol 4000 did not. Analysis of the continuous extrusion process was done using a design of experiments. It showed that powder feed rate and speed of the stretching device used after extrusion predominantly determine the diameter of the filament and thereby the mechanical resilience of a filament.

Conversion of municipal solid wastes to carboxylic acids by thermophilic fermentation.

PubMed

Chan, Wen Ning; Holtzapple, Mark T

2003-11-01

The purpose of this research is to generate carboxylic acids from the biodegradable fraction of municipal solid wastes (MSW) and municipal sewage sludge (MSS) by using a thermophilic (55 degrees C), anaerobic, high-solid fermentation. With terrestrial inocula, the highest total carboxylic acid concentration achieved was 20.5 g/L, the highest conversion obtained was 69%, and the highest acetic acid selectivity was 86.4%. Marine inocula were also used to compare against terrestrial sources. Continuum particle distribution modeling (CPDM) was used to predict the final acid product concentrations and substrate conversions at a wide range of liquid residence times (LRT) and volatile solid loading rates (VSLR). "Maps" showing the product concentration and conversion for various LRT and VSLR were generated from CPDM. The predictions were compared to the experimental results. On average, the difference between the predicted and experimental values were 13% for acid concentration and 10% for conversion. CPDM "maps" show that marine inocula produce higher concentrations than terrestrial inocula.

Co-digestion of solid waste: Towards a simple model to predict methane production.

PubMed

Kouas, Mokhles; Torrijos, Michel; Schmitz, Sabine; Sousbie, Philippe; Sayadi, Sami; Harmand, Jérôme

2018-04-01

Modeling methane production is a key issue for solid waste co-digestion. Here, the effect of a step-wise increase in the organic loading rate (OLR) on reactor performance was investigated, and four new models were evaluated to predict methane yields using data acquired in batch mode. Four co-digestion experiments of mixtures of 2 solid substrates were conducted in semi-continuous mode. Experimental methane yields were always higher than the BMP values of mixtures calculated from the BMP of each substrate, highlighting the importance of endogenous production (methane produced from auto-degradation of microbial community and generated solids). The experimental methane productions under increasing OLRs corresponded well to the modeled data using the model with constant endogenous production and kinetics identified at 80% from total batch time. This model provides a simple and useful tool for technical design consultancies and plant operators to optimize the co-digestion and the choice of the OLRs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Kinetic modelling of anaerobic hydrolysis of solid wastes, including disintegration processes.

PubMed

García-Gen, Santiago; Sousbie, Philippe; Rangaraj, Ganesh; Lema, Juan M; Rodríguez, Jorge; Steyer, Jean-Philippe; Torrijos, Michel

2015-01-01

A methodology to estimate disintegration and hydrolysis kinetic parameters of solid wastes and validate an ADM1-based anaerobic co-digestion model is presented. Kinetic parameters of the model were calibrated from batch reactor experiments treating individually fruit and vegetable wastes (among other residues) following a new protocol for batch tests. In addition, decoupled disintegration kinetics for readily and slowly biodegradable fractions of solid wastes was considered. Calibrated parameters from batch assays of individual substrates were used to validate the model for a semi-continuous co-digestion operation treating simultaneously 5 fruit and vegetable wastes. The semi-continuous experiment was carried out in a lab-scale CSTR reactor for 15 weeks at organic loading rate ranging between 2.0 and 4.7 gVS/Ld. The model (built in Matlab/Simulink) fit to a large extent the experimental results in both batch and semi-continuous mode and served as a powerful tool to simulate the digestion or co-digestion of solid wastes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Foil Bearing Starting Considerations and Requirements for Rotorcraft Engine Applications

NASA Technical Reports Server (NTRS)

Radil, Kevin C.; DellaCorte, Christopher

2009-01-01

Foil gas bearings under development for rotorcraft-sized, hot core engine applications have been susceptible to damage from the slow acceleration and rates typically encountered during the pre-ignition stage in conventional engines. Recent laboratory failures have been assumed to be directly linked to operating foil bearings below their lift-off speed while following conventional startup procedures for the engines. In each instance, the continuous sliding contact between the foils and shaft was believed to thermally overload the bearing and cause the engines to fail. These failures highlight the need to characterize required acceleration rates and minimum operating speeds for these applications. In this report, startup experiments were conducted with a large, rotorcraft engine sized foil bearing under moderate load and acceleration rates to identify the proper start procedures needed to avoid bearing failure. The results showed that a bearing under a 39.4 kPa static load can withstand a modest acceleration rate of 500 rpm/s and excessive loitering below the bearing lift-off speed provided an adequate solid lubricant is present.

Contribution of a submerged membrane bioreactor in the treatment of synthetic effluent contaminated by Bisphenol-A: mechanism of BPA removal and membrane fouling.

PubMed

Seyhi, Brahima; Drogui, Patrick; Buelna, Gerardo; Azaïs, Antonin; Heran, Marc

2013-09-01

A submerged membrane bioreactor has been operated at the laboratory scale for the treatment of a synthetic effluent containing Bisphenol-A (BPA). COD, NH4-N, PO4-P and BPA were eliminated respectively, at 99%, 99%, 61% and 99%. The increase of volumetric loading rate from 0 to 21.6 g/m(3)/d did not affect the performance of the MBR system. However, the removal rate decreased rapidly when the BPA loading rate increased above 21.6 g/m(3)/d. The adsorption process of BPA on the biomass was very well described by Freundlich and Langmuir isotherms. Subsequently, biodegradation of BPA occurred and followed the first order kinetic reaction, with a constant rate of 1.13 ± 0.22 h(-1). During treatment, membrane fouling was reversible in the first 84 h of filtration, and then became irreversible. The membrane fouling was mainly due to the accumulation of suspended solid and development of biofilm on the membrane surface. Copyright © 2013 Elsevier Ltd. All rights reserved.

Grey water treatment by the slanted soil system with unsorted soil media.

PubMed

Ushijima, Ken; Tanaka, Erina; Suzuki, Laís Yuko; Hijikata, Nowaki; Funamizu, Naoyuki; Ito, Ryusei

2015-01-01

This study evaluated the performance of unsorted soil media in the slanted soil treatment system, in terms of removal efficiency in suspended solids (SS), chemical oxygen demand (COD), linear alkylbenzene sulphonate (LAS) and Escherichia coli, and lifetime until clogging occurs. Unsorted soil performed longer lifetime until clogging than sorted fine soil. Removal of SS, COD, and LAS also performed same or better level in unsorted soil than fine soil. As reaction coefficients of COD and LAS were described as a function of the hydraulic loading rate, we can design a slanted soil system according to the expected hydraulic loading rate and the targeted level of COD or LAS in effluent. Regarding bacteria removal, unsorted soil performed sufficient reduction of E. coli for 5 weeks; however, the removal process occurred throughout all four chambers, while that of fine soil occurred in one to two chambers.

Estimation of the dust production rate from the tungsten armour after repetitive ELM-like heat loads

NASA Astrophysics Data System (ADS)

Pestchanyi, S.; Garkusha, I.; Makhlaj, V.; Landman, I.

2011-12-01

Experimental simulations for the erosion rate of tungsten targets under ITER edge-localized mode (ELM)-like surface heat loads of 0.75 MJ m-2 causing surface melting and of 0.45 MJ m-2 without melting have been performed in the QSPA-Kh50 plasma accelerator. Analytical considerations allow us to conclude that for both energy deposition values the erosion mechanism is solid dust ejection during surface cracking under the action of thermo-stress. Tungsten influx into the ITER containment of NW~5×1018 W per medium size ELM of 0.75 MJ m-2 and 0.25 ms time duration has been estimated. The radiation cooling power of Prad=150-300 MW due to such influx of tungsten is intolerable: it should cool the ITER core to 1 keV within a few seconds.

Modal Survey of ETM-3, A 5-Segment Derivative of the Space Shuttle Solid Rocket Booster

NASA Technical Reports Server (NTRS)

Nielsen, D.; Townsend, J.; Kappus, K.; Driskill, T.; Torres, I.; Parks, R.

2005-01-01

The complex interactions between internal motor generated pressure oscillations and motor structural vibration modes associated with the static test configuration of a Reusable Solid Rocket Motor have potential to generate significant dynamic thrust loads in the 5-segment configuration (Engineering Test Motor 3). Finite element model load predictions for worst-case conditions were generated based on extrapolation of a previously correlated 4-segment motor model. A modal survey was performed on the largest rocket motor to date, Engineering Test Motor #3 (ETM-3), to provide data for finite element model correlation and validation of model generated design loads. The modal survey preparation included pretest analyses to determine an efficient analysis set selection using the Effective Independence Method and test simulations to assure critical test stand component loads did not exceed design limits. Historical Reusable Solid Rocket Motor modal testing, ETM-3 test analysis model development and pre-test loads analyses, as well as test execution, and a comparison of results to pre-test predictions are discussed.

Preliminary 2-D shell analysis of the space shuttle solid rocket boosters

NASA Technical Reports Server (NTRS)

Knight, Norman F., Jr.; Gillian, Ronnie E.; Nemeth, Michael P.

1987-01-01

A two-dimensional shell model of an entire solid rocket booster (SRB) has been developed using the STAGSC-1 computer code and executed on the Ames CRAY computer. The purpose of these analyses is to calculate the overall deflection and stress distributions for the SRB when subjected to mechanical loads corresponding to critical times during the launch sequence. The mechanical loading conditions for the full SRB arise from the external tank (ET) attachment points, the solid rocket motor (SRM) pressure load, and the SRB hold down posts. The ET strut loads vary with time after the Space Shuttle main engine (SSME) ignition. The SRM internal pressure varies axially by approximately 100 psi. Static analyses of the full SRB are performed using a snapshot picture of the loads. The field and factory joints are modeled by using equivalent stiffness joints instead of detailed models of the joint. As such, local joint behavior cannot be obtained from this global model.

Modeling propellant-based stimulation of a borehole with peridynamics

DOE PAGES

Panchadhara, Rohan; Gordon, Peter A.; Parks, Michael L.

2017-02-27

A non-local formulation of classical continuum mechanics theory known as peridynamics is used to study fracture initiation and growth from a wellbore penetrating the subsurface within the context of propellant-based stimulation. The principal objectives of this work are to analyze the influence of loading conditions on the resulting fracture pattern, to investigate the effect of in-situ stress anisotropy on fracture propagation, and to assess the suitability of peridynamics for modeling complex fracture formation. In peridynamics, the momentum equation from the classical theory of solid mechanics is replaced by a non-local analogue, which results in an integrodifferential conservation equation. A continuummore » material is discretized with a set of material points that interact with all other points within a specified distance. Interactions between points are governed by bonds that can deform and break depending on loading conditions. The accumulated breakage of bonds gives rise to a picture of complex growth of fractures that is seen as a key advantage in the peridynamic representation of discontinuities. It is shown that the loading rate significantly influences the number and ex- tent of fractures initiated from a borehole. Results show that low loading rates produce fewer but longer fractures, whereas high loading rates produce numerous shorter fractures around the borehole. The numerical method is able to predict fracture growth patterns over a wide range of loading and stress conditions. Our results also show that fracture growth is attenuated with increasing in-situ confining stress, and, in the case of confining stress anisotropy, fracture extensions are largest in the direction perpendicular to the minimum compressive stress. Since the results are in broad qualitative agreement with experimental and numerical studies found in the literature, suggesting that peridynamics can be a powerful tool in the study of complex fracture network formation.« less

Modeling propellant-based stimulation of a borehole with peridynamics

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

Panchadhara, Rohan; Gordon, Peter A.; Parks, Michael L.

A non-local formulation of classical continuum mechanics theory known as peridynamics is used to study fracture initiation and growth from a wellbore penetrating the subsurface within the context of propellant-based stimulation. The principal objectives of this work are to analyze the influence of loading conditions on the resulting fracture pattern, to investigate the effect of in-situ stress anisotropy on fracture propagation, and to assess the suitability of peridynamics for modeling complex fracture formation. In peridynamics, the momentum equation from the classical theory of solid mechanics is replaced by a non-local analogue, which results in an integrodifferential conservation equation. A continuummore » material is discretized with a set of material points that interact with all other points within a specified distance. Interactions between points are governed by bonds that can deform and break depending on loading conditions. The accumulated breakage of bonds gives rise to a picture of complex growth of fractures that is seen as a key advantage in the peridynamic representation of discontinuities. It is shown that the loading rate significantly influences the number and ex- tent of fractures initiated from a borehole. Results show that low loading rates produce fewer but longer fractures, whereas high loading rates produce numerous shorter fractures around the borehole. The numerical method is able to predict fracture growth patterns over a wide range of loading and stress conditions. Our results also show that fracture growth is attenuated with increasing in-situ confining stress, and, in the case of confining stress anisotropy, fracture extensions are largest in the direction perpendicular to the minimum compressive stress. Since the results are in broad qualitative agreement with experimental and numerical studies found in the literature, suggesting that peridynamics can be a powerful tool in the study of complex fracture network formation.« less

Biogas production from municipal solid wastes using an integrated rotary drum and anaerobic-phased solids digester system.

PubMed

Zhu, Baoning; Zhang, Ruihong; Gikas, Petros; Rapport, Joshua; Jenkins, Bryan; Li, Xiujin

2010-08-01

This research was conducted to develop an integrated rotary drum reactor (RDR)-anaerobic-phased solids (APS) digester system for the treatment of municipal solid waste (MSW) to produce biogas energy and achieve waste reduction. A commercial RDR facility was used to provide a 3-d pretreatment and sufficient separation of the organics from MSW and then the organics were digested in a laboratory APS-digester system for biogas production. The organics generated from the RDR contained 50% total solids (TS) and 36% volatile solids (VS) on wet basis. The APS-digester was started at an organic loading rate (OLR) of 3.1 gVS L(-1) d(-1) and operated at three higher OLRs of 4.6, 7.7 and 9.2 gVS L(-1) d(-1). At the OLR of 9.2 gVS L(-1) d(-1) the system biogas production rate was 3.5 L L(-1) d(-1) and the biogas and methane yields were 0.38 and 0.19 L gVS(-1), respectively. Anaerobic digestion resulted in 38% TS reduction and 53% VS reduction in the organic solids. It was found that the total VFA concentration reached a peak value of 15,000 mg L(-1) as acetic acid in the first 3d of batch digestion and later decreased to about 500 mg L(-1). The APS-digester system remained stable at each OLRs for over 100d with the pH in the hydrolysis reactors in the range of 7.3-7.8 and the pH in the biogasification reactor in 7.9-8.1. The residual solids after the digestion had a high heating value of 14.7 kJ gTS(-1). Copyright 2010 Elsevier Ltd. All rights reserved.

Comparison of semi-batch vs. continuously fed anaerobic bioreactors for the treatment of a high-strength, solids-rich pumpkin-processing wastewater.

PubMed

del Agua, Isabel; Usack, Joseph G; Angenent, Largus T

2015-01-01

The objective of this work was to compare two different high-rate anaerobic bioreactor configurations--the anaerobic sequencing batch reactor (ASBR) and the upflow anaerobic solid removal (UASR) reactor--for the treatment of a solid-rich organic wastewater with a high strength. The two, 4.5-L reactors were operated in parallel for close to 100 days under mesophilic conditions (37°C) with non-granular biomass by feeding a pumpkin wastewater with ∼4% solids. The organic loading rate of pumpkin wastewater was increased periodically to a maximum of 8 g COD L(-1) d(-1) by shortening the hydraulic retention time to 5.3 days. Compositional analysis of pumpkin wastewater revealed deficiencies in the trace metal cobalt and alkalinity. With supplementation, the ASBR outperformed the UASR reactor with total chemical oxygen demand (COD) removal efficiencies of 64% and 53%, respectively, achieving a methane yield of 0.27 and 0.20 L CH4 g(-1) COD fed to the ASBR and UASR, respectively. The better performance realized with the ASBR and this specific wastewater was attributed to its semi-batch, dynamic operating conditions rather than the continuous operating conditions of the UASR reactor.

Effect of Humic Acid on the Removal of Chromium(VI) and the Production of Solids in Iron Electrocoagulation.

PubMed

Pan, Chao; Troyer, Lyndsay D; Liao, Peng; Catalano, Jeffrey G; Li, Wenlu; Giammar, Daniel E

2017-06-06

Iron-based electrocoagulation can be highly effective for Cr(VI) removal from water supplies. However, the presence of humic acid (HA) inhibited the rate of Cr(VI) removal in electrocoagulation, with the greatest decreases in Cr(VI) removal rate at higher pH. This inhibition was probably due to the formation of Fe(II) complexes with HA that are more rapidly oxidized than uncomplexed Fe(II) by dissolved oxygen, making less Fe(II) available for reduction of Cr(VI). Close association of Fe(III), Cr(III), and HA in the solid products formed during electrocoagulation influenced the fate of both Cr(III) and HA. At pH 8, the solid products were colloids (1-200 nm) with Cr(III) and HA concentrations in the filtered fraction being quite high, while at pH 6 these concentrations were low due to aggregation of small particles. X-ray diffraction and X-ray absorption fine structure spectroscopy indicated that the iron oxides produced were a mixture of lepidocrocite and ferrihydrite, with the proportion of ferrihydrite increasing in the presence of HA. Cr(VI) was completely reduced to Cr(III) in electrocoagulation, and the coordination environment of the Cr(III) in the solids was similar regardless of the humic acid loading, pH, and dissolved oxygen level.

United States Air Force Research Initiation Program for 1988. Volume 3

DTIC Science & Technology

1990-04-01

Assignment for Dr. Kenneth M. Sobel Flight Control Design 210-9MG-035 90 Comparative Burning Rates and Duplex Dr. Forrest Thomas (1987) Loads of Solid...Patterson Air Force Base. The test configuration has been designed for injecting fuel droplets in a well controlled laminar on well-characterized turbulent...its counter response may be significant, our system has thus achieved some measure of control over when non -critical processing is actually performed

The Importance of the Solids Loading on Confirming the Dielectric Nanosize Dependence of BaTiO3 Powders by Slurry Method

PubMed Central

Zhou, Wei; Nie, Yi Mei; Li, Shu Jing; Liang, Hai Yan

2013-01-01

The dielectric nanosize dependence of BaTiO3 powders was investigated by the slurry method, where two series of BaTiO3 slurries with 10 vol% and 30 vol% solids loadings were prepared as model samples. Applying the Bruggeman-Hanai equation, the high-frequency limiting permittivity (ε h) of the slurries was extracted from the dielectric spectra. The ε h of the 10 vol% slurry showed abnormal size independence in the range from 100 nm to 700 nm, and the ε h of the 30 vol% slurry exhibited good agreement with the previous prediction. Through analysing quantitatively the response of ε h to the changing permittivity of the powders under different solids loading, it was found that the ε h of the slurry with lower solids loading is more inclined to be interfered by the systematic and random errors. Furthermore, a high permittivity value was found in the BaTiO3 powders with 50 nm particle size. PMID:23844376

Recent advances in solid polymer electrolyte fuel cell technology with low platinum loading electrodes

NASA Technical Reports Server (NTRS)

Srinivasan, Supramaniam; Manko, David J.; Koch, Hermann; Enayetullah, Mohammad A.; Appleby, A. John

1989-01-01

Of all the fuel cell systems only alkaline and solid polymer electrolyte fuel cells are capable of achieving high power densities (greater than 1 W/sq cm) required for terrestrial and extraterrestrial applications. Electrode kinetic criteria for attaining such high power densities are discussed. Attainment of high power densities in solid polymer electrolyte fuel cells has been demonstrated earlier by different groups using high platinum loading electrodes (4 mg/sq cm). Recent works at Los Alamos National Laboratory and at Texas A and M University (TAMU) demonstrated similar performance for solid polymer electrolyte fuel cells with ten times lower platinum loading (0.45 mg/sq cm) in the electrodes. Some of the results obtained are discussed in terms of the effects of type and thickness of membrane and of the methods platinum localization in the electrodes on the performance of a single cell.

Enhanced delivery of fixed-dose combination of synergistic antichagasic agents posaconazole-benznidazole based on amorphous solid dispersions.

PubMed

Figueirêdo, Camila Bezerra Melo; Nadvorny, Daniela; Vieira, Amanda Carla Quintas de Medeiros; Schver, Giovanna Christinne Rocha de Medeiros; Soares Sobrinho, José Lamartine; Rolim Neto, Pedro José; Lee, Ping I; Soares, Monica Felts de La Roca

2018-07-01

Posaconazole (PCZ) and benznidazole (BNZ) are known to show synergetic effect in treating the acute and chronic phases of Chagas disease, a neglected parasitic disease. However, as both compounds are poorly water soluble, the development of amorphous solid dispersions (ASDs) of a PCZ/BNZ fixed-dose combination in a water-soluble polymer becomes an attractive option to increase their apparent solubility and dissolution rate, potentially improving their oral bioavailability. The initial approach was to explore solvent evaporated solid dispertion (SD) systems for a PCZ/BNZ 50:50 (wt%) combination at several total drug loading levels (from SD with 10% to 50% drug loading) in water-soluble carriers, including polyvinylpyrrolidone (PVP K-30) and vinylpyrrolidone-vinyl acetate copolymer (PVPVA 64). Based on comparison of non-sink in vitro dissolution performance, ASD systems based on PVPVA was identified as the most effective carrier for a 50:50 (w/w %) fixed-dose combination of PCZ/BNZ to increase their apparent solubility and dissolution rate, mainly at 10% drug loading, which shows more expressive values of area under the curve (AUC) (7336.04 ± 3.77 min.μL/mL for PCZ and 15,795.02 ± 7.29 min.μL/mL for BNZ). Further characterization with polarized microscopy, powder X-ray diffraction, and thermal analysis reveals that there exists a threshold drug loading level at about 30% PCZ/BNZ, below which ASDs are obtained and above which a certain degree of crystallinity tends to result. Moreover, infrared spectroscopic analysis reveals the lack of hydrogen bonding interactions between the drugs (PCZ and BNZ) and the polymer (PVPVA) in the ASD, this is also confirmed through molecular dynamics simulations. The molecular modeling results further show that even in the absence of meaningful hydrogen bonding interactions, there is a greater tendency for PVPVA to interact preferentially with PCZ and BNZ through electrostatic interactions thereby contributing to the stability of the system. Thus, the present SD system has the advantage of presenting a fixed-dese combination of two synergistic antichagasic agents PCZ and BNZ together in amorphous form stabilized in the PVPVA matrix with enhanced dissolution, potentially improving their bioavailability and therapeutic activity in treating Chagas disease. Copyright © 2018 Elsevier B.V. All rights reserved.

Short-term response of the solid Earth to cryosphere fluctuations and the earthquake cycle in south-central Alaska

NASA Astrophysics Data System (ADS)

Sauber, J. M.; Freymueller, J. T.; Han, S. C.; Davis, J. L.; Ruppert, N. A.

2016-12-01

In southern Alaska surface deformation and gravimetric change are associated with the seismic cycle as well as a strong seasonal cycle of snow accumulation and melt and a variable rate of glacier mass wastage. Numerical modeling of the solid Earth response to cryosphere change on a variety of temporal and spatial scales plays a critical role in supporting the interpretation of time-variable gravity and other geodetic data. In this study we calculate the surface displacements and stresses associated with variable spatial and temporal cryospheric loading and unloading in south-central coastal Alaska. A challenging aspect of estimating the response of the solid Earth to short-term (months to 102 years) regional cryospheric fluctuations is choosing the rock mechanics constitutive laws appropriate to this region. Here we report calculated differences in the predicted surface displacements and stresses during the GRACE time period (2002 to present). Broad-scale, GRACE-derived estimates of cryospheric mass change, along with independent snow melt onset/refreeze timing, snow depth and annual glacier wastage estimates from a variety of methods, were used to approximate the magnitude and timing of cryospheric load changes. We used the CIG finite element code PyLith to enable input of spatially complex surface loads. An as example of our evaluation of the influence of variable short-term surface loads, we calculated and contrasted the predicted surface displacements and stresses for a cooler than average and higher precipitation water year (WY12) versus a warmer than average year (WY05). Our calculation of these comparative stresses is motivated by our earlier empirical evaluation of the influence of short-term cryospheric fluctuations on the background seismic rate between 1988-2006 (Sauber and Ruppert, 2008). During the warmer than average years between 2002-2006 we found a stronger seasonal dependency in the frequency of small tectonic events in the Icy Bay region relative to cooler years. To date, we have focused our 3-D modeling on changes in the thickness of the primarily elastic layer and we also varied the Maxwell viscoelastic relaxation times for the lower crust and upper mantle. We anticipate exploring the influence of transient rheologies and testing alternate 3-D rheological structures.

Anaerobic Digestion Model No. 1 Simulation of High Solids Anaerobic Digestion with Feasibility Study for El Gabal El Asfar Water Resource Recovery Facility.

PubMed

Aboulfotoh, Ahmed M

2018-03-01

  Performance of continuous mesophilic high solids anaerobic digestion (HSAD) was simulated using Anaerobic Digestion Model No. 1 (ADM1), under different conditions (solids concentrations, sludge retention time (SRT), organic loading rate (OLR), and type of sludge). Implementation of ADM1, using the proposed biochemical parameters, proved to be a useful tool for the prediction and control of HSAD as the model predicted the behavior of the tested sets of data with considerable accuracy, especially for SRT more than 13 days. The model was then used to investigate the possibility of changing the existing conventional anaerobic digestion (CAD) units in Gabal El Asfar water resource recovery facility into HSAD, instead of establishing new CAD units, and results show that the system will be feasible. HSAD will produce the same bioenergy combined with a decrease in capital, operational, and maintenance costs.

One-step continuous extrusion process for the manufacturing of solid dispersions.

PubMed

Maniruzzaman, M; Nair, A; Scoutaris, N; Bradley, Michael S A; Snowden, M J; Douroumis, D

2015-12-30

The purpose of this study was to evaluate the performance of synthetic magnesium aluminometasilicate (MAS) as a novel inorganic carrier in hot melt extrusion (HME) processing of indomethacin (IND) for the development of solid dispersions. A continuous extrusion process at various IND/excipient blend ratios (20%, 30% and 40%) was performed using a twin-screw extruder. Physicochemical characterization carried out by SEM, DSC, and XRPD demonstrated the presence of IND in amorphous nature within the porous network of the inorganic material for all extruded formulations. Further, AFM and FTIR studies revealed a single-phase amorphous system and intermolecular H-bonding formation. The IND/MAS extrudates showed enhanced INM dissolution rates within 100% been released within 1h. Stability studies under accelerated conditions (40°C, RH 75%) showed that MAS retained the physical stability of the amorphous solid dispersions even at high drug loadings for 12 months. Copyright © 2015 Elsevier B.V. All rights reserved.

Biogasification of municipal solid wastes

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

Diaz, L.F.; Savage, G.M.; Trezek, G.J.

1981-06-01

A series of experiments on the anaerobic digestion of the organic fraction of municipal refuse was performed. The refuse fraction used in the study was one of the portions segregated in a resource recovery system developed at the University of California, Berkeley. The scale of experiments includes 4, 9, and 1600-L digesters. The refuse used as feed was enriched by the addition of raw sewage sludge in various ratios, i.e., from 0-100% of the total volatile solids. No other sources of nutrients or chemicals for pH control were introduced into the reactors. Organic loading rates ranging from 1.1 to 6.4more » g of volatile solids/Ld were obtained. Typical hydraulic detention times were 15 to 30 days. Temperatures were kept within the range of 72 to 104 F (22 to 40 C). Digestion efficiency was based on energy conversion and gas production.« less

Ethanol production from mixtures of sugarcane bagasse and Dioscorea composita extracted residue with high solid loading.

PubMed

Ye, Guangying; Zeng, Defu; Zhang, Shuaishuai; Fan, Meishan; Zhang, Hongdan; Xie, Jun

2018-06-01

Various mixing ratios of alkali pretreated sugarcane bagasse and starch-rich waste Dioscorea composita hemls extracted residue (DER) were evaluated via simultaneous saccharification and fermentation (SSF) with 12% (w/w) solid loading, and the mixture ratio of 1:1 achieved the highest ethanol concentration and yield. When the solid loading was increased from 12% to 32%, the ethanol concentration was increased to 72.04 g/L, whereas the ethanol yield was reduced from 84.40% to 73.71%. With batch feeding and the addition of 0.1% (w/v) Tween 80, the final ethanol concentration and yield of SSF at 34% loading were 82.83 g/L and 77.22%, respectively. Due to the integration with existing starch-based ethanol industry, the co-fermentation is expected to be a competitive alternative form for cellulosic ethanol production. Copyright © 2018 Elsevier Ltd. All rights reserved.

Feasibility of solid oxide fuel cell dynamic hydrogen coproduction to meet building demand

NASA Astrophysics Data System (ADS)

Shaffer, Brendan; Brouwer, Jacob

2014-02-01

A dynamic internal reforming-solid oxide fuel cell system model is developed and used to simulate the coproduction of electricity and hydrogen while meeting the measured dynamic load of a typical southern California commercial building. The simulated direct internal reforming-solid oxide fuel cell (DIR-SOFC) system is controlled to become an electrical load following device that well follows the measured building load data (3-s resolution). The feasibility of the DIR-SOFC system to meet the dynamic building demand while co-producing hydrogen is demonstrated. The resulting thermal responses of the system to the electrical load dynamics as well as those dynamics associated with the filling of a hydrogen collection tank are investigated. The DIR-SOFC system model also allows for resolution of the fuel cell species and temperature distributions during these dynamics since thermal gradients are a concern for DIR-SOFC.

An exploratory investigation of cumulative shock fatigue.

NASA Technical Reports Server (NTRS)

Simonson, D.; Byrne, J. G.

1972-01-01

A simple device for producing cumulative shock loading in solids is described. The device uses a ballistic-impact-driven projectile to introduce high-stress waves into a solid. The impact time and load amplitude can be varied to produce fracture in one or several impacts in PMMA rods. The wavefront approached a square wave shape. Materials other than PMMA were loaded to failure to demonstrate the versatility of the device. Fracture morphologies observed with optical and scanning-electron microscopy are described.

Quality of water and bottom sediments, and nutrient and dissolved-solids loads in the Apopka-Beauclair Canal, Lake County, Florida, 1986-90

USGS Publications Warehouse

Schiffer, D.M.

1994-01-01

Nutrient-rich water enters Lake Beauclair and other lakes downstream from Lake Apopka in the Ocklawaha River chain of lakes in central Florida. Two sources of the nutrient-rich water are Lake Apopka outflow and drainage from farming operations adjacent to the Apopka-Beauclair Canal. Two flow and water- quality monitoring sites were established to measure nutrient and dissolved-solids loads at the outflow from lake Apopka and at a control structure on the Apopka-Beauclair Canal downstream from farming activities. Samples were collected biweekly for analysis of nutrients and monthly for analysis of major ions for 4 years. Most of the nutrient load transported through the lock and dam on the Apopka-Beauclair Canal was transported during periods of high discharge. In April 1987, when discharges were as high as 589 cubic feet per second, loads transported through the lock and dam accounted for 59 percent of the ammonia-plus- organic nitrogen load, 61 percent of the total nitrogen load, and 59 percent of the phosphorus load transported during the 1987 water year. Constituent concentrations in annual bottom sediment samples from the canal indicated that most of the constituent load is not being transported down- stream. An alternative approach was derived for determining the relative constituent load from farm input along the canal: Load computations using this approach indicated that, with the exception of phosphorus, nutrient and dissolved-solids loads due to farm activity along the canal account for 10 percent or less of the total load at the Apopka-Beauclair canal lock and dam. (USGS)

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

Shekiro, III, Joseph; Chen, Xiaowen; Smith, Holly

Dilute-acid pretreatment has proven to be a robust means of converting herbaceous feedstock to fermentable sugars. However, it also releases acetic acid, a known fermentation inhibitor, from acetyl groups present in the biomass. A mild, dilute alkaline extraction stage was implemented prior to acid pretreatment to separate acetic acid from the hydrolysate sugar stream. This step, termed deacetylation, improved the glucose and xylose yields from enzymatic hydrolysis and ethanol yields from fermentation of the sugars relative to the control experiments using dilute-acid pretreatment of native corn stover without deacetylation. While promising, deacetylation as it was historically practiced is conducted atmore » low solids loadings, and at fixed conditions. Thus, many questions have been left unanswered, including the relationship between sodium hydroxide and solids loading, and acetate and xylan solubilization, as well as the impact of temperature and residence time on the process efficacy. A central composite experiment was designed to evaluate the impact of solids loading, sodium hydroxide loading, reaction time and temperature during deacetylation on the acetate and xylan solubilization of corn stover. Using the ANOVA test, it became apparent that neither of the responses was significantly impacted by the solids loading, while the reaction time was a minor factor - the responses were largely driven by reaction temperature and the sodium hydroxide loading. Based on the results, we successfully demonstrated the ability to transition the low-solids (10 % w/w) deacetylation process to a higher-solids process (30 % w/w) with minimal impact on the ability to extract acetate from biomass. Conditions were selected to minimize xylose loss during deacetylation, while also removing 70 % of acetyl groups. The impact of selected conditions on the enzymatic hydrolysis and fermentation was further investigated. In conclusion, evaluation of the whole-process impact demonstrated that despite the upfront reduction in carbohydrate loss during deacetylation, the overall process sugar yields were depressed by the high-solids, low alkali process relative to the historical control. Consequently, ethanol titers were reduced, though strong fermentation performance was still observed, indicating that 70 % acetate removal is sufficient to depress acetic acid concentrations to a level that does not substantially inhibit ethanol fermentation by rZymomo nas.« less

Glacier Ice Mass Fluctuations and Fault Instability in Tectonically Active Southern Alaska

NASA Technical Reports Server (NTRS)

SauberRosenberg, Jeanne M.; Molnia, Bruce F.

2003-01-01

Across southern Alaska the northwest directed subduction of the Pacific plate is accompanied by accretion of the Yakutat terrane to continental Alaska. This has led to high tectonic strain rates and dramatic topographic relief of more than 5000 meters within 15 km of the Gulf of Alaska coast. The glaciers of this area are extensive and include large glaciers undergoing wastage (glacier retreat and thinning) and surges. The large glacier ice mass changes perturb the tectonic rate of deformation at a variety of temporal and spatial scales. We estimated surface displacements and stresses associated with ice mass fluctuations and tectonic loading by examining GPS geodetic observations and numerical model predictions. Although the glacial fluctuations perturb the tectonic stress field, especially at shallow depths, the largest contribution to ongoing crustal deformation is horizontal tectonic strain due to plate convergence. Tectonic forces are thus the primary force responsible for major earthquakes. However, for geodetic sites located < 10-20 km from major ice mass fluctuations, the changes of the solid Earth due to ice loading and unloading are an important aspect of interpreting geodetic results. The ice changes associated with Bering Glacier s most recent surge cycle are large enough to cause discernible surface displacements. Additionally, ice mass fluctuations associated with the surge cycle can modify the short-term seismicity rates in a local region. For the thrust faulting environment of the study region a large decrease in ice load may cause an increase in seismic rate in a region close to failure whereas ice loading may inhibit thrust faulting.

Performance assessment of two-stage anaerobic digestion of kitchen wastes.

PubMed

Bo, Zhang; Pin-Jing, He

2014-01-01

This study is aimed at investigating the performance of the two-phase anaerobic digestion of kitchen wastes in a lab-scale setup. The semi-continuous experiment showed that the two-phase anaerobic digestion of kitchen wastes had a bioconversion rate of 83%, biogas yield of 338 mL x (g chemical oxygen demand (COD))(-1) and total solid conversion of 63% when the entire two-phase anaerobic digestion process was subjected to an organic loading rate (OLR) of 10.7 g x (L d)(-1). In the hydrolysis-acidogenesis process, the efficiency of solubilization decreased from 72.6% to 41.1%, and the acidogenesis efficiency decreased from 31.8% to 17.8% with an increase in the COD loading rate. On the other hand, the performance of the subsequent methanogenic process was not susceptible to the increase in the feeding COD loading rate in the hydrolysis-acidogenesis stage. Lactic acid was one of the main fermentation products, accounting for over 40% of the total soluble COD in the fermentation liquid. The batch experiments indicated that the lactic acid was the earliest predominant fermentation product, and distributions of fermentation products were pH dependent. Results showed that increasing the feeding OLR of kitchen wastes made the two-stage anaerobic digestion process more effective. Moreover, there was a potential improvement in the performance of anaerobic digestion of kitchen wastes with a corresponding improvement in the hydrolysis process.

Acetone-butanol-ethanol production from Kraft paper mill sludge by simultaneous saccharification and fermentation.

PubMed

Guan, Wenjian; Shi, Suan; Tu, Maobing; Lee, Yoon Y

2016-01-01

Paper mill sludge (PS), a solid waste from pulp and paper industry, was investigated as a feedstock for acetone-butanol-ethanol (ABE) production by simultaneous saccharification and fermentation (SSF). ABE fermentation of paper sludge by Clostridium acetobutylicum required partial removal of ash in PS to enhance its enzymatic digestibility. Enzymatic hydrolysis was found to be a rate-limiting step in the SSF. A total of 16.4-18.0g/L of ABE solvents were produced in the SSF of de-ashed PS with solid loading of 6.3-7.4% and enzyme loading of 10-15FPU/g-glucan, and the final solvent yield reached 0.27g/g sugars. No pretreatment and pH control were needed in ABE fermentation of paper sludge, which makes it an attractive feedstock for butanol production. The results suggested utilization of paper sludge should not only consider the benefits of buffering effect of CaCO3 in fermentation, but also take into account its inhibitory effect on enzymatic hydrolysis. Published by Elsevier Ltd.

Improved Friction and Wear of M50 Steel Composites Incorporated with ZnO as a Solid Lubricant with Different Concentrations Under Different Loads

NASA Astrophysics Data System (ADS)

Essa, F. A.; Zhang, Qiaoxin; Huang, Xingjiu; Ibrahim, Ahmed Mohamed Mahmoud; Ali, Mohamed Kamal Ahmed; Abdelkareem, Mohamed A. A.; Elagouz, Ahmed

2017-10-01

This experimental study explores improving the tribological behavior of M50 steel using ZnO as a solid lubricant with different concentrations of 5, 10, 15, 20, and 25 wt.%. Tribological tests were conducted using pin-on-disk tribometer under different loads of 3, 6, 9, and 12 N and constant sliding speed of 0.2 m s-1 in air. XRD, EPMA, FESEM, EDS mapping, and XPS tests were performed to understand the major mechanisms leading to improve the tribological and mechanical properties of M50 composites. Results showed that the best tribological and mechanical properties were obtained at 20.0 wt.% of ZnO. Friction coefficient and wear rate were reduced by 52.909 and 70%, respectively, due to the formation of tribo-films on the worn surfaces. Furthermore, the hardness of M50 composites increased by 27.86%. Our study provides results with suggestions to overcome the challenges facing the technology when using M50 matrix composites in mechanical applications.

Enhanced active liposomal loading of a poorly soluble ionizable drug using supersaturated drug solutions.

PubMed

Modi, Sweta; Xiang, Tian-Xiang; Anderson, Bradley D

2012-09-10

Nanoparticulate drug carriers such as liposomal drug delivery systems are of considerable interest in cancer therapy because of their ability to passively accumulate in solid tumors. For liposomes to have practical utility for antitumor therapy in patients, however, optimization of drug loading, retention, and release kinetics are necessary. Active loading is the preferred method for optimizing loading of ionizable drugs in liposomes as measured by drug-to-lipid ratios, but the extremely low aqueous solubilities of many anticancer drug candidates may limit the external driving force, thus slowing liposomal uptake during active loading. This report demonstrates the advantages of maintaining drug supersaturation during active loading. A novel method was developed for creating and maintaining supersaturation of a poorly soluble camptothecin analogue, AR-67 (7-t-butyldimethylsilyl-10-hydroxycamptothecin), using a low concentration of a cyclodextrin (sulfobutylether-β-cyclodextrin) to inhibit crystallization over a 48 h period. Active loading into liposomes containing high concentrations of entrapped sodium or calcium acetate was monitored using drug solutions at varying degrees of supersaturation. Liposomal uptake rates increased linearly with the degree of supersaturation of drug in the external loading solution. A mathematical model was developed to predict the rate and extent of drug loading versus time, taking into account the chemical equilibria inside and outside of the vesicles and the transport kinetics of various permeable species across the lipid bilayer and the dialysis membrane. Intraliposomal sink conditions were maintained by the high internal pH caused by the efflux of acetic acid and exchange with AR-67, which undergoes lactone ring-opening, ionization, and membrane binding in the interior of the vesicles. The highest drug to lipid ratio achieved was 0.17 from a supersaturated solution at a total drug concentration of 0.6 mg/ml. The rate and extent of loading was similar when a different intraliposomal metal cation (sodium) was used instead of calcium. The proposed method may have general application in overcoming the formulation challenges associated with the liposomal delivery of poorly soluble, ionizable anticancer agents. Copyright © 2012 Elsevier B.V. All rights reserved.

Combined substrate, enzyme and yeast feed in simultaneous saccharification and fermentation allow bioethanol production from pretreated spruce biomass at high solids loadings

PubMed Central

2014-01-01

Background Economically feasible cellulosic ethanol production requires that the process can be operated at high solid loadings, which currently imparts technical challenges including inefficient mixing leading to heat and mass transfer limitations and high concentrations of inhibitory compounds hindering microbial activity during simultaneous saccharification and fermentation (SSF) process. Consequently, there is a need to develop cost effective processes overcoming the challenges when working at high solid loadings. Results In this study we have modified the yeast cultivation procedure and designed a SSF process to address some of the challenges at high water insoluble solids (WIS) content. The slurry of non-detoxified pretreated spruce when used in a batch SSF at 19% (w/w) WIS was found to be inhibitory to Saccharomyces cerevisiae Thermosacc that produced 2 g l-1 of ethanol. In order to reduce the inhibitory effect, the non-washed solid fraction containing reduced amount of inhibitors compared to the slurry was used in the SSF. Further, the cells were cultivated in the liquid fraction of pretreated spruce in a continuous culture wherein the outflow of cell suspension was used as cell feed to the SSF reactor in order to maintain the metabolic state of the cell. Enhanced cell viability was observed with cell, enzyme and substrate feed in a SSF producing 40 g l-1 ethanol after 96 h corresponding to 53% of theoretical yield based on available hexose sugars compared to 28 g l-1 ethanol in SSF with enzyme and substrate feed but no cell feed resulting in 37% of theoretical yield at a high solids loading of 20% (w/w) WIS content. The fed-batch SSF also significantly eased the mixing, which is usually challenging in batch SSF at high solids loading. Conclusions A simple modification of the cell cultivation procedure together with a combination of yeast, enzyme and substrate feed in a fed-batch SSF process, made it possible to operate at high solids loadings in a conventional bioreactor. The proposed process strategy significantly increased the yeast cell viability and overall ethanol yield. It was also possible to obtain 4% (w/v) ethanol concentration, which is a minimum requirement for an economical distillation process. PMID:24713027

Combined substrate, enzyme and yeast feed in simultaneous saccharification and fermentation allow bioethanol production from pretreated spruce biomass at high solids loadings.

PubMed

Koppram, Rakesh; Olsson, Lisbeth

2014-04-08

Economically feasible cellulosic ethanol production requires that the process can be operated at high solid loadings, which currently imparts technical challenges including inefficient mixing leading to heat and mass transfer limitations and high concentrations of inhibitory compounds hindering microbial activity during simultaneous saccharification and fermentation (SSF) process. Consequently, there is a need to develop cost effective processes overcoming the challenges when working at high solid loadings. In this study we have modified the yeast cultivation procedure and designed a SSF process to address some of the challenges at high water insoluble solids (WIS) content. The slurry of non-detoxified pretreated spruce when used in a batch SSF at 19% (w/w) WIS was found to be inhibitory to Saccharomyces cerevisiae Thermosacc that produced 2 g l-1 of ethanol. In order to reduce the inhibitory effect, the non-washed solid fraction containing reduced amount of inhibitors compared to the slurry was used in the SSF. Further, the cells were cultivated in the liquid fraction of pretreated spruce in a continuous culture wherein the outflow of cell suspension was used as cell feed to the SSF reactor in order to maintain the metabolic state of the cell. Enhanced cell viability was observed with cell, enzyme and substrate feed in a SSF producing 40 g l-1 ethanol after 96 h corresponding to 53% of theoretical yield based on available hexose sugars compared to 28 g l-1 ethanol in SSF with enzyme and substrate feed but no cell feed resulting in 37% of theoretical yield at a high solids loading of 20% (w/w) WIS content. The fed-batch SSF also significantly eased the mixing, which is usually challenging in batch SSF at high solids loading. A simple modification of the cell cultivation procedure together with a combination of yeast, enzyme and substrate feed in a fed-batch SSF process, made it possible to operate at high solids loadings in a conventional bioreactor. The proposed process strategy significantly increased the yeast cell viability and overall ethanol yield. It was also possible to obtain 4% (w/v) ethanol concentration, which is a minimum requirement for an economical distillation process.

Treatment performances of French constructed wetlands: results from a database collected over the last 30 years.

PubMed

Morvannou, A; Forquet, N; Michel, S; Troesch, S; Molle, P

2015-01-01

Approximately 3,500 constructed wetlands (CWs) provide raw wastewater treatment in France for small communities (<5,000 people equivalent). Built during the past 30 years, most consist of two vertical flow constructed wetlands (VFCWs) in series (stages). Many configurations exist, with systems associated with horizontal flow filters or waste stabilization ponds, vertical flow with recirculation, partially saturated systems, etc. A database analyzed 10 years earlier on the classical French system summarized the global performances data. This paper provides a similar analysis of performance data from 415 full-scale two-stage VFCWs from an improved database expanded by monitoring data available from Irstea and the French technical department. Trends presented in the first study are confirmed, exhibiting high chemical oxygen demand (COD), total suspended solids (TSS) and total Kjeldahl nitrogen (TKN) removal rates (87%, 93% and 84%, respectively). Typical concentrations at the second-stage outlet are 74 mgCOD L(-1), 17 mgTSS L(-1) and 11 mgTKN L(-1). Pollutant removal performances are summarized in relation to the loads applied at the first treatment stage. While COD and TSS removal rates remain stable over the range of applied loads, the spreading of TKN removal rates increases as applied loads increase.

Differential behaviour of a Lesser Himalayan watershed in extreme rainfall regimes

NASA Astrophysics Data System (ADS)

Chauhan, Pankaj; Singh, Nilendu; Chauniyal, Devi Datt; Ahluwalia, Rajeev S.; Singhal, Mohit

2017-03-01

Climatic extremes including precipitation are bound to intensify in the global warming environment. The present study intends to understand the response of the Tons sub-watershed in Lesser Himalaya, in 3 years with entirely different hydrological conditions (July 2008-June 2011) in terms of discharge, sediment flux and denudation rates. Within an uncertainty limit of ±20%, the mean interannual discharge (5.74 ± 1.44 m 3 s -1) (±SE), was found highly variable (CV: 151%; 0.8-38 m 3 s -1). In a normal rainfall year (2008-2009; ˜1550 mm), the discharge was 5.12 ± 1.75 m 3 s -1, whereas in a drought year (2009-2010), it reduced by 30% with the reduction in ˜23% rainfall (CV: 85%). In an excessive rainfall year (once-in-a-century event) (2010-2011; ˜3050 mm), discharge as well as total solid load was ˜200% higher. Monsoon months (July-September) accounted for more than 90% of the annual solid load transport. The ratio of dissolved to suspended solid (C/P ratio) was consistently low (<1) during monsoon months and higher (1-7) during the rest of the dry period. C/P ratio was inversely ( R 2=0.49), but significantly ( P <0.001) related to the rainfall. The average mechanical erosion rate in the three different rainfall years was 0.24, 0.19 and 1.03 mmyr -1, whereas the chemical erosion was estimated at 0.12, 0.11 and 0.46 mmyr -1, respectively. Thus, the average denudation rate of the Tons sub-watershed has been estimated at 0.33 mmyr -1 (excluding extreme rainfall year: 1.5 mmyr -1). Our results have implications to understand the hydrological behaviour of the Lesser Himalayan watersheds and will be valuable for the proposed and several upcoming small hydropower plants in the region in the context of regional ecology and natural resource management.

Future Antarctic bed topography and its implications for ice sheet dynamics

NASA Astrophysics Data System (ADS)

Adhikari, S.; Ivins, E. R.; Larour, E.; Seroussi, H.; Morlighem, M.; Nowicki, S.

2014-06-01

The Antarctic bedrock is evolving as the solid Earth responds to the past and ongoing evolution of the ice sheet. A recently improved ice loading history suggests that the Antarctic Ice Sheet (AIS) has generally been losing its mass since the Last Glacial Maximum. In a sustained warming climate, the AIS is predicted to retreat at a greater pace, primarily via melting beneath the ice shelves. We employ the glacial isostatic adjustment (GIA) capability of the Ice Sheet System Model (ISSM) to combine these past and future ice loadings and provide the new solid Earth computations for the AIS. We find that past loading is relatively less important than future loading for the evolution of the future bed topography. Our computations predict that the West Antarctic Ice Sheet (WAIS) may uplift by a few meters and a few tens of meters at years AD 2100 and 2500, respectively, and that the East Antarctic Ice Sheet is likely to remain unchanged or subside minimally except around the Amery Ice Shelf. The Amundsen Sea Sector in particular is predicted to rise at the greatest rate; one hundred years of ice evolution in this region, for example, predicts that the coastline of Pine Island Bay will approach roughly 45 mm yr-1 in viscoelastic vertical motion. Of particular importance, we systematically demonstrate that the effect of a pervasive and large GIA uplift in the WAIS is generally associated with the flattening of reverse bed slope, reduction of local sea depth, and thus the extension of grounding line (GL) towards the continental shelf. Using the 3-D higher-order ice flow capability of ISSM, such a migration of GL is shown to inhibit the ice flow. This negative feedback between the ice sheet and the solid Earth may promote stability in marine portions of the ice sheet in the future.

Future Antarctic bed topography and its implications for ice sheet dynamics

NASA Astrophysics Data System (ADS)

Adhikari, S.; Ivins, E.; Larour, E.; Seroussi, H.; Morlighem, M.; Nowicki, S.

2014-01-01

The Antarctic bedrock is evolving as the solid Earth responds to the past and ongoing evolution of the ice sheet. A~recently improved ice loading history suggests that the Antarctic Ice Sheet (AIS) is generally losing its mass since the last glacial maximum (LGM). In a sustained warming climate, the AIS is predicted to retreat at a greater pace primarily via melting beneath the ice shelves. We employ the glacial isostatic adjustment (GIA) capability of the Ice Sheet System Model (ISSM) to combine these past and future ice loadings and provide the new solid Earth computations for the AIS. We find that the past loading is relatively less important than future loading on the evolution of the future bed topography. Our computations predict that the West Antarctic Ice Sheet (WAIS) may uplift by a few meters and a few tens of meters at years 2100 and 2500 AD, respectively, and that the East Antarctic Ice Sheet (EAIS) is likely to remain unchanged or subside minimally except around the Amery Ice Shelf. The Amundsen Sea Sector in particular is predicted to rise at the greatest rate; one hundred years of ice evolution in this region, for example, predicts that the coastline of Pine Island Bay approaches roughly 45 mm yr-1 in viscoelastic vertical motion. Of particular importance, we systematically demonstrate that the effect of a pervasive and large GIA uplift in the WAIS is associated with the flattening of reverse bed, reduction of local sea depth, and thus the extension of grounding line (GL) towards the continental shelf. Using the 3-D higher-order ice flow capability of ISSM, such a migration of GL is shown to inhibit the ice flow. This negative feedback between the ice sheet and the solid Earth may promote the stability to marine portions of the ice sheet in future.

Future Antarctic Bed Topography and Its Implications for Ice Sheet Dynamics

NASA Technical Reports Server (NTRS)

Adhikari, Surendra; Ivins, Erik R.; Larour, Eric Y.; Seroussi, Helene L.; Morlighem, Mathieu; Nowicki, S.

2014-01-01

The Antarctic bedrock is evolving as the solid Earth responds to the past and ongoing evolution of the ice sheet. A recently improved ice loading history suggests that the Antarctic Ice Sheet (AIS) has generally been losing its mass since the Last Glacial Maximum. In a sustained warming climate, the AIS is predicted to retreat at a greater pace, primarily via melting beneath the ice shelves.We employ the glacial isostatic adjustment (GIA) capability of the Ice Sheet System Model (ISSM) to combine these past and future ice loadings and provide the new solid Earth computations for the AIS.We find that past loading is relatively less important than future loading for the evolution of the future bed topography. Our computations predict that the West Antarctic Ice Sheet (WAIS) may uplift by a few meters and a few tens of meters at years AD 2100 and 2500, respectively, and that the East Antarctic Ice Sheet is likely to remain unchanged or subside minimally except around the Amery Ice Shelf. The Amundsen Sea Sector in particular is predicted to rise at the greatest rate; one hundred years of ice evolution in this region, for example, predicts that the coastline of Pine Island Bay will approach roughly 45mmyr-1 in viscoelastic vertical motion. Of particular importance, we systematically demonstrate that the effect of a pervasive and large GIA uplift in the WAIS is generally associated with the flattening of reverse bed slope, reduction of local sea depth, and thus the extension of grounding line (GL) towards the continental shelf. Using the 3-D higher-order ice flow capability of ISSM, such a migration of GL is shown to inhibit the ice flow. This negative feedback between the ice sheet and the solid Earth may promote stability in marine portions of the ice sheet in the future.

Study of solid rocket motor for a space shuttle booster. Appendix A: SRM water entry loads

NASA Technical Reports Server (NTRS)

1972-01-01

An analysis of the water entry loads imposed on the reusable solid propellant rocket engine of the space shuttle following parachute descent is presented. The cases discussed are vertical motion, horizontal motion, and motion after penetration. Mathematical models, diagrams, and charts are included to support the theoretical considerations.

Methane production by anaerobic digestion of water hyacinth (Eichhornia crassipes)

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

Klass, D.L.; Ghosh, S.

1980-01-01

Water hyacinth under conventional high-rate digestion conditions exhibited higher methane yields and energy recovery efficiencies when grown in sewage-fed lagoons as compared to the corresponding values obtained with water hyacinth grown in a fresh-water pond. Mesophilic digestion provided the highest feed energy recovered in the product gas as methane while thermophilic digestion, when operated at sufficiently high loading rates and reduced detention times, gave the highest specific methane production rates. Methane yields, volatile solids reduction, and energy recovery as methane for the sewage-grown water hyacinth were in the same range as those observed for other biomass substrates when digested undermore » similar conditions.« less

A new drilling method—Earthworm-like vibration drilling

PubMed Central

Wang, Peng; Wang, Ruihe

2018-01-01

The load transfer difficulty caused by borehole wall friction severely limits the penetration rate and extended-reach limit of complex structural wells. A new friction reduction technology termed “earthworm-like drilling” is proposed in this paper to improve the load transfer of complex structural wells. A mathematical model based on a “soft-string” model is developed and solved. The results show that earthworm-like drilling is more effective than single-point vibration drilling. The amplitude and frequency of the pulse pressure and the installation position of the shakers have a substantial impact on friction reduction and load transfer. An optimization model based on the projection gradient method is developed and used to optimize the position of three shakers in a horizontal well. The results verify the feasibility and advantages of earthworm-like drilling, and establish a solid theoretical foundation for its application in oil field drilling. PMID:29641615

A new drilling method-Earthworm-like vibration drilling.

PubMed

Wang, Peng; Ni, Hongjian; Wang, Ruihe

2018-01-01

The load transfer difficulty caused by borehole wall friction severely limits the penetration rate and extended-reach limit of complex structural wells. A new friction reduction technology termed "earthworm-like drilling" is proposed in this paper to improve the load transfer of complex structural wells. A mathematical model based on a "soft-string" model is developed and solved. The results show that earthworm-like drilling is more effective than single-point vibration drilling. The amplitude and frequency of the pulse pressure and the installation position of the shakers have a substantial impact on friction reduction and load transfer. An optimization model based on the projection gradient method is developed and used to optimize the position of three shakers in a horizontal well. The results verify the feasibility and advantages of earthworm-like drilling, and establish a solid theoretical foundation for its application in oil field drilling.

Constitutive Models Based on Compressible Plastic Flows

NASA Technical Reports Server (NTRS)

Rajendran, A. M.

1983-01-01

The need for describing materials under time or cycle dependent loading conditions has been emphasized in recent years by several investigators. In response to the need, various constitutive models describing the nonlinear behavior of materials under creep, fatigue, or other complex loading conditions were developed. The developed models for describing the fully dense (non-porous) materials were mostly based on uncoupled plasticity theory. The improved characterization of materials provides a better understanding of the structual response under complex loading conditions. The pesent studies demonstrate that the rate or time dependency of the response of a porous aggregate can be incorporated into the nonlinear constitutive behavior of a porous solid by appropriately modeling the incompressible matrix behavior. It is also sown that the yield function which wads determined by a continuum mechanics approach must be verified by appropriate experiments on void containing sintered materials in order to obtain meaningful numbers for the constants that appear in the yield function.

Asymptotic analysis of stability for prismatic solids under axial loads

NASA Astrophysics Data System (ADS)

Scherzinger, W.; Triantafyllidis, N.

1998-06-01

This work addresses the stability of axially loaded prismatic beams with any simply connected crosssection. The solids obey a general class of rate-independent constitutive laws, and can sustain finite strains in either compression or tension. The proposed method is based on multiple scale asymptotic analysis, and starts with the full Lagrangian formulation for the three-dimensional stability problem, where the boundary conditions are chosen to avoid the formation of boundary layers. The calculations proceed by taking the limit of the beam's slenderness parameter, ɛ (ɛ 2 ≡ area/length 2), going to zero, thus resulting in asymptotic expressions for the critical loads and modes. The analysis presents a consistent and unified treatment for both compressive (buckling) and tensile (necking) instabilities, and is carried out explicitly up to o( ɛ4) in each case. The present method circumvents the standard structural mechanics approach for the stability problem of beams which requires the choice of displacement and stress field approximations in order to construct a nonlinear beam theory. Moreover, this work provides a consistent way to calculate the effect of the beam's slenderness on the critical load and mode to any order of accuracy required. In contrast, engineering theories give accurately the lowest order terms ( O( ɛ2)—Euler load—in compression or O(1)—maximum load—in tension) but give only approximately the next higher order terms, with the exception of simple section geometries where exact stability results are available. The proposed method is used to calculate the critical loads and eigenmodes for bars of several different cross-sections (circular, square, cruciform and L-shaped). Elastic beams are considered in compression and elastoplastic beams are considered in tension. The O( ɛ2) and O( ɛ4) asymptotic results are compared to the exact finite element calculations for the corresponding three-dimensional prismatic solids. The O( ɛ4) results give significant improvement over the O( ɛ2) results, even for extremely stubby beams, and in particular for the case of cross-sections with commensurate dimensions.

Development and characterisation of sustained release solid dispersion oral tablets containing the poorly water soluble drug disulfiram.

PubMed

Shergill, Mandip; Patel, Mina; Khan, Siraj; Bashir, Ayesha; McConville, Christopher

2016-01-30

Administration of drugs via the oral route is the most common and preferred route due to its ease of administration, cost-effectiveness and flexibility in design. However, if the drug being administered has limited aqueous solubility it can result in poor bioavailability. Furthermore, the low pH of the stomach as well as enzymatic activity can result in drugs delivered via the oral route being rapidly metabolised and degraded. Here we demonstrate the development and characterisation of sustained release solid dispersion oral tablets, containing the poorly water-soluble drug disulfiram (DSF). The tablets, which are manufactured from two different polymers (Kolliphor(®) P 188 and P 237) specifically designed for the manufacture of solid dispersions and two different polymers (Kollidon(®) SR and HPMC) specifically designed to provide sustained release, can enhance the solubility of DSF, sustain its release, while protecting it from degradation in simulated gastric fluid (SGF). The paper demonstrates that when using the hot melt method at 80°C the DSF loading capacity of the Kolliphor(®) P 188 and P 237 polymers is approximately 43 and 46% respectively, with the DSF completely in an amorphous state. The addition of 80% Kollidon(®) SR to the formulation completely protected the DSF in SGF for up to 70 min with 16% degradation after 120 min, while 75% degradation occurred after 120 min with the addition of 80% HPMC. The release rate of DSF can be manipulated by both the loading and type of sustained release polymer used, with HPMC providing for a much faster release rate compared to Kollidon(®) SR. Copyright © 2015 Elsevier B.V. All rights reserved.

Drug Loading of Mesoporous Silicon

NASA Astrophysics Data System (ADS)

Moffitt, Anne; Coffer, Jeff; Wang, Mengjia

2011-03-01

The nanostructuring of crystalline solids with low aqueous solubilities by their incorporation into mesoporous host materials is one route to improve the bioavailability of such solids. Earlier studies suggest that mesoporous Si (PSi), with pore widths in the range of 5-50 nm, is a candidate for such an approach. In this presentation, we describe efforts to load curcumin into free-standing microparticles of PSi. Curcumin is a compound extracted from turmeric root, which is an ingredient of curry. Curucmin has shown activity against selected cancer cell lines, bacteria, and other medical conditions. However, curcumin has a very low bioavailability due to its extremely low water solubility (0.6 μ g/mL). Incorporation of curcumin was achieved by straightforward loading of the molten solid at 185circ; C. Loading experiments were performed using PSi particles of two different size ranges, 45-75 μ m and 150-250 μ m. Longer loading times and ratio of curcumin to PSi leads to a higher percentage of loaded curcumin in both PSi particle sizes (as determined by weight difference). The extent of curcumin crystallinity was assessed by x-ray diffraction (XRD). The solubility and release kinetics of loaded curcumin from the PSi was determined by extraction into water at 37circ; C, with analysis using UV-VIS spectrometry. NSF-REU and TCU.

The Effect of Journal Roughness and Foil Coatings on the Performance of Heavily Loaded Foil Air Bearings

NASA Technical Reports Server (NTRS)

Radil, Kevin C.; DellaCorte, Christopher

2001-01-01

Foil air bearing load capacity tests were conducted to investigate if a solid lubricant coating applied to the surface of the bearing's top foil can function as a break-in coating. Two foil coating materials, a conventional soft polymer film (polyimide) and a hard ceramic (alumina), were independently evaluated against as-ground and worn (run-in) journals coated with NASA PS304, a high-temperature solid lubricant composite coating. The foil coatings were evaluated at journal rotational speeds of 30,000 rpm and at 25 C. Tests were also performed on a foil bearing with a bare (uncoated) nickel-based superalloy top foil to establish a baseline for comparison. The test results indicate that the presence of a top foil solid lubricant coating is effective at increasing the load capacity performance of the foil bearing. Compared to the uncoated baseline, the addition of the soft polymer coating on the top foil increased the bearing load coefficient by 120% when operating against an as-ground journal surface and 85 percent against a run-in journal surface. The alumina coating increased the load coefficient by 40% against the as-ground journal but did not have any affect when the bearing was operated with the run-in journal. The results suggest that the addition of solid lubricant films provide added lubrication when the air film is marginal indicating that as the load capacity is approached foil air bearings transition from hydrodynamic to mixed and boundary lubrication.

On-line determination of Sb(III) and total Sb using baker's yeast immobilized on polyurethane foam and hydride generation inductively coupled plasma optical emission spectrometry

NASA Astrophysics Data System (ADS)

Menegário, Amauri A.; Silva, Ariovaldo José; Pozzi, Eloísa; Durrant, Steven F.; Abreu, Cassio H.

2006-09-01

The yeast Saccharomyces cerevisiae was immobilized in cubes of polyurethane foam and the ability of this immobilized material to separate Sb(III) and Sb(V) was investigated. A method based on sequential determination of total Sb (after on-line reduction of Sb(V) to Sb(III) with thiourea) and Sb(III) (after on-line solid-liquid phase extraction) by hydride generation inductively coupled plasma optical emission spectrometry is proposed. A flow system assembled with solenoid valves was used to manage all stages of the process. The effects of pH, sample loading and elution flow rates on solid-liquid phase extraction of Sb(III) were evaluated. Also, the parameters related to on-line pre-reduction (reaction coil and flow rates) were optimized. Detection limits of 0.8 and 0.15 μg L - 1 were obtained for total Sb and Sb(III), respectively. The proposed method was applied to the analysis of river water and effluent samples. The results obtained for the determination of total Sb were in agreement with expected values, including the river water Standard Reference Material 1640 certified by the National Institute of Standards and Technology (NIST). Recoveries of Sb(III) and Sb(V) in spiked samples were between 81 ± 19 and 111 ±15% when 120 s of sample loading were used.

Thermophilic Dry Methane Fermentation of Distillation Residue Eluted from Ethanol Fermentation of Kitchen Waste and Dynamics of Microbial Communities.

PubMed

Huang, Yu-Lian; Tan, Li; Wang, Ting-Ting; Sun, Zhao-Yong; Tang, Yue-Qin; Kida, Kenji

2017-01-01

Thermophilic dry methane fermentation is advantageous for feedstock with high solid content. Distillation residue with 65.1 % moisture content was eluted from ethanol fermentation of kitchen waste and subjected to thermophilic dry methane fermentation, after adjusting the moisture content to 75 %. The effect of carbon to nitrogen (C/N) ratio on thermophilic dry methane fermentation was investigated. Results showed that thermophilic dry methane fermentation could not be stably performed for >10 weeks at a C/N ratio of 12.6 and a volatile total solid (VTS) loading rate of 1 g/kg sludge/d; however, it was stably performed at a C/N ratio of 19.8 and a VTS loading rate of 3 g/kg sludge/d with 83.4 % energy recovery efficiency. Quantitative PCR analysis revealed that the number of bacteria and archaea decreased by two orders of magnitude at a C/N ratio of 12.6, whereas they were not influenced at a C/N ratio of 19.8. Microbial community analysis revealed that the relative abundance of protein-degrading bacteria increased and that of organic acid-oxidizing bacteria and acetic acid-oxidizing bacteria decreased at a C/N ratio of 12.6. Therefore, there was accumulation of NH 4 + and acetic acid, which inhibited thermophilic dry methane fermentation.

[Determination of estrogen residues in drinking water by on-line solid phase extraction based on sol-gel technique coupled with high performance liquid chromatography].

PubMed

Li, Longfei; Su, Min; Shi, Xiaolei; Wang, Yana; Wang, Minmin; He, Jinxing

2014-02-01

A method for the determination of diethylstilbestrol (DES), hexestrol (HEX) and dienestrol (DS) residues in drinking water was established by on-line solid phase extraction (SPE) coupled with high performance liquid chromatography (HPLC). The material synthesized on the base of sol-gel technology was employed as adsorbent. This material was prepared using 3-aminopropyltriethoxysilane (APTES) as the functional monomer, tetraethoxysilane (TEOS) as the crosslinking agent, and acetic acid as the initiator. The synthesized adsorbent showed outstanding property for the estrogen extraction. The estrogen can be caught effectively from water samples and the extraction can be achieved rapidly. Some important parameters, such as pH of sample solution, eluent solvents, loading flow rate, which might influence extraction efficiency, were optimized. The results indicated that the limit of detection (S/N = 3) of the developed method could reach 0.07-0.13 microg/L under the conditions of pH 7.0 of sample solution, methanol and 1% (v/v) acetic acid aqueous solution as the eluent solvent and the loading flow rate of 2 mL/min. The recoveries of the three estrogens from the water samples at three spiked levels ranged from 82.31% to 99.43% with RSD of 1.61%-7.15%. The method was simple, rapid, and suitable to detect the trace residues of estrogens in drinking water.

Sludge settling processes in SBR-related sewage treatment plants according to the Biocos method.

PubMed

Meusel, S; Englert, R

2004-01-01

This paper describes the investigations in a sedimentation and circulation reactor (SU-reactor) of a three-phase Biocos plant. The aim of these investigations was the determination of the temporal and depth-dependent distribution of suspended solid contents, as well as describing the sludge sedimentation curves. The calculated results reveal peculiarities of the Biocos method with regard to sedimentation processes. In the hydraulically uninterrupted (pre-)settling phase, a sludge level depth was observed, which remained constant over the reactor surface and increased linearly according to the sludge volume. The settling and the thickening processes of this phase corresponded to a large extent to the well-known settling test in a one-litre measuring cylinder. During the discharge phase, the investigated settling rate was overlaid by the surface loading rate and the sludge level changed depending on the difference between those two parameters. The solid distribution of the A-phase indicated a formation of functional zones, which were influenced by the surface loading. The formation was comparable to the formation of layers in secondary settling tanks with vertical flow. The concentration equalisation between the biological reactor and the SU-reactor proved to be problematic during the circulation phase, because a type of internal sludge circulation occurred in the SU-reactor. A permanent sludge recirculation seems to be highly recommendable.

Fermentation of sugarcane bagasse and chicken manure to calcium carboxylates under thermophilic conditions.

PubMed

Fu, Zhihong; Holtzapple, Mark T

2010-09-01

Sugarcane bagasse and chicken manure were anaerobically fermented to carboxylic acids using a mixed culture of marine microorganisms at 55 degrees C. Using the MixAlco process--an example of consolidated bioprocessing--the resulting carboxylate salts can be converted to mixed alcohol fuels or gasoline. To enhance digestibility, sugarcane bagasse was lime pretreated with 0.1 g Ca(OH)(2)/g dry biomass at 100 degrees C for 2 h. Four-stage countercurrent fermentation of 80% sugarcane bagasse/20% chicken manure was performed at various volatile solids (VS) loading rates and liquid residence times. Calcium carbonate was used as a buffer during fermentation. The highest acid productivity of 0.79 g/(L day) occurred at a total acid concentration of 21.5 g/L. The highest conversion (0.59 g VS digested/g VS fed) and yield (0.18 g total acids/g VS fed) occurred at a total acid concentration of 15.5 g/L. The continuum particle distribution model (CPDM) predicted the experimental total acid concentrations and conversions at an average error of 10.14% and 12.68%, respectively. CPDM optimizations show that high conversion (>80%) and total acid concentration of 21.3 g/L are possible with 300 g substrate/(L liquid), 30 days liquid residence time, and 3 g/(L day) solid loading rate. Thermophilic fermentation has a higher acetate content (approximately 63 wt%) than mesophilic fermentation (approximately 39 wt%).

Pilot scale dilute acid pretreatment of rice straw and fermentable sugar recovery at high solid loadings.

PubMed

Kapoor, Manali; Soam, Shveta; Agrawal, Ruchi; Gupta, Ravi P; Tuli, Deepak K; Kumar, Ravindra

2017-01-01

The aim of this work was to study the dilute acid pretreatment of rice straw (RS) and fermentable sugar recovery at high solid loadings at pilot scale. A series of pretreatment experiments were performed on RS resulting in >25wt% solids followed by enzymatic hydrolysis without solid-liquid separation at 20 and 25wt% using 10FPU/g of the pretreated residue. The overall sugar recovery including the sugars released in pretreatment and enzymatic hydrolysis was calculated along with a mass balance. Accordingly, the optimized conditions, i.e. 0.35wt% acid, 162°C and 10min were identified. The final glucose and xylose concentrations obtained were 83.3 and 31.9g/L respectively resulting in total concentration of 115.2g/L, with a potential to produce >50g/L of ethanol. This is the first report on pilot scale study on acid pretreatment of RS in a screw feeder horizontal reactor followed by enzymatic hydrolysis at high solid loadings. Copyright © 2016 Elsevier Ltd. All rights reserved.

Micro-engineered first wall tungsten armor for high average power laser fusion energy systems

NASA Astrophysics Data System (ADS)

Sharafat, Shahram; Ghoniem, Nasr M.; Anderson, Michael; Williams, Brian; Blanchard, Jake; Snead, Lance; HAPL Team

2005-12-01

The high average power laser program is developing an inertial fusion energy demonstration power reactor with a solid first wall chamber. The first wall (FW) will be subject to high energy density radiation and high doses of high energy helium implantation. Tungsten has been identified as the candidate material for a FW armor. The fundamental concern is long term thermo-mechanical survivability of the armor against the effects of high temperature pulsed operation and exfoliation due to the retention of implanted helium. Even if a solid tungsten armor coating would survive the high temperature cyclic operation with minimal failure, the high helium implantation and retention would result in unacceptable material loss rates. Micro-engineered materials, such as castellated structures, plasma sprayed nano-porous coatings and refractory foams are suggested as a first wall armor material to address these fundamental concerns. A micro-engineered FW armor would have to be designed with specific geometric features that tolerate high cyclic heating loads and recycle most of the implanted helium without any significant failure. Micro-engineered materials are briefly reviewed. In particular, plasma-sprayed nano-porous tungsten and tungsten foams are assessed for their potential to accommodate inertial fusion specific loads. Tests show that nano-porous plasma spray coatings can be manufactured with high permeability to helium gas, while retaining relatively high thermal conductivities. Tungsten foams where shown to be able to overcome thermo-mechanical loads by cell rotation and deformation. Helium implantation tests have shown, that pulsed implantation and heating releases significant levels of implanted helium. Helium implantation and release from tungsten was modeled using an expanded kinetic rate theory, to include the effects of pulsed implantations and thermal cycles. Although, significant challenges remain micro-engineered materials are shown to constitute potential candidate FW armor materials.

Interferometric measurement of displacements and displacement velocities for nondestructive quality control

NASA Astrophysics Data System (ADS)

Shpeĭzman, V. V.; Peschanskaya, N. N.

2007-07-01

It is shown that the interferometric measurement of small displacements and small-displacement velocities can be used to determine internal stresses or the stresses induced by an applied load in solids and to control structural changes in them. The interferometric method based on the measurement of the reaction of a solid to a small perturbation in its state of stress is applied to determine stresses from the deviation of the reaction to perturbations from that in the standard stress-free case. For structural control, this method is employed to study the specific features of the characteristics of microplastic deformation that appear after material treatment or operation and manifest themselves in the temperature and force dependences of the rate of a small inelastic strain.

30 CFR 75.1318 - Loading boreholes.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) When loading boreholes drilled at an angle of 45 degrees or greater from the horizontal in solid rock... the borehole; and (2) The explosive cartridges shall be loaded in a manner that provides contact...

Solid particle erosion of polymers and composites

NASA Astrophysics Data System (ADS)

Friedrich, K.; Almajid, A. A.

2014-05-01

After a general introduction to the subject of solid particle erosion of polymers and composites, the presentation focusses more specifically on the behavior of unidirectional carbon fiber (CF) reinforced polyetheretherketone (PEEK) composites under such loadings, using different impact conditions and erodents. The data were analyzed on the basis of a newly defined specific erosive wear rate, allowing a better comparison of erosion data achieved under various testing conditions. Characteristic wear mechanisms of the CF/PEEK composites consisted of fiber fracture, matrix cutting and plastic matrix deformation, the relative contribution of which depended on the impingement angles and the CF orientation. The highest wear rates were measured for impingement angles between 45 and 60°. Using abrasion resistant neat polymer films (in this case PEEK or thermoplastic polyurethane (TPU) ones) on the surface of a harder substrate (e.g. a CF/PEEK composite plate) resulted in much lower specific erosive wear rates. The use of such polymeric films can be considered as a possible method to protect composite surfaces from damage caused by minor impacts and erosion. In fact, they are nowadays already successfully applied as protections for wind energy rotor blades.

Modelling of slaughterhouse solid waste anaerobic digestion: determination of parameters and continuous reactor simulation.

PubMed

López, Iván; Borzacconi, Liliana

2010-10-01

A model based on the work of Angelidaki et al. (1993) was applied to simulate the anaerobic biodegradation of ruminal contents. In this study, two fractions of solids with different biodegradation rates were considered. A first-order kinetic was used for the easily biodegradable fraction and a kinetic expression that is function of the extracellular enzyme concentration was used for the slowly biodegradable fraction. Batch experiments were performed to obtain an accumulated methane curve that was then used to obtain the model parameters. For this determination, a methodology derived from the "multiple-shooting" method was successfully used. Monte Carlo simulations allowed a confidence range to be obtained for each parameter. Simulations of a continuous reactor were performed using the optimal set of model parameters. The final steady-states were determined as functions of the operational conditions (solids load and residence time). The simulations showed that methane flow peaked at a flow rate of 0.5-0.8 Nm(3)/d/m(reactor)(3) at a residence time of 10-20 days. Simulations allow the adequate selection of operating conditions of a continuous reactor. (c) 2010 Elsevier Ltd. All rights reserved.

Complex coacervation of collagen hydrolysate extracted from leather solid wastes and chitosan for controlled release of lavender oil.

PubMed

Ocak, Buğra

2012-06-15

In the world, approximately 600,000 metric tonnes of chromium-containing solid wastes are generated by the leather industry each year. Environmental concerns and escalating landfill costs are becoming increasingly serious problems to the leather industry and seeking solutions to these problems is a prime concern in much research today. In this study, solid collagen-based protein hydrolysate was isolated from chromium-tanned leather wastes and its chemical properties were determined. Microcapsules of collagen hydrolysate (CH) - chitosan (C) crosslinked with glutaraldehyde (GA) containing Lavender oil (LO) were prepared by complex coacervation method. The effects of various processing parameters, including the CH to C ratio, LO content, and GA, on the oil load (%), oil content (%), encapsulation efficiency (%) and release rate of LO from microcapsules were investigated. As the ratio of C present in the CH/C mixture and crosslinking density increased, the release rate of LO from microcapsules slowed down. Optical and scanning electron microscopy images illustrated that the LO microcapsules were spherical in shape. Fourier transform infrared spectroscopy (FTIR) studies confirmed that there was no significant interaction between CH/C complex and LO. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effect of Compression on the Molecular Arrangement of Itraconazole-Soluplus Solid Dispersions: Induction of Liquid Crystals or Exacerbation of Phase Separation?

PubMed

Singh, Abhishek; Bharati, Avanish; Frederiks, Pauline; Verkinderen, Olivier; Goderis, Bart; Cardinaels, Ruth; Moldenaers, Paula; Van Humbeeck, Jan; Van den Mooter, Guy

2016-06-06

Predensification and compression are unit operations imperative to the manufacture of tablets and capsules. Such stress-inducing steps can cause destabilization of solid dispersions which can alter their molecular arrangement and ultimately affect dissolution rate and bioavailability. In this study, itraconazole-Soluplus solid dispersions with 50% (w/w) drug loading prepared by hot-melt extrusion (HME) were investigated. Compression was performed at both pharmaceutically relevant and extreme compression pressures and dwell times. The starting materials, powder, and compressed solid dispersions were analyzed using modulated differential scanning calorimetry (MDSC), X-ray diffraction (XRD), small- and wide-angle X-ray scattering (SWAXS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), and broadband dielectric spectroscopy (BDS). MDSC analysis revealed that compression promotes phase separation of solid dispersions as indicated by an increase in glass transition width, occurrence of a peak in the nonreversing heat flow signal, and an increase in the net heat of fusion indicating crystallinity in the systems. SWAXS analysis ruled out the presence of mesophases. BDS measurements elucidated an increase in the Soluplus-rich regions of the solid dispersion upon compression. FTIR indicated changes in the spatiotemporal architecture of the solid dispersions mediated via disruption in hydrogen bonding and ultimately altered dynamics. These changes can have significant consequences on the final stability and performance of the solid dispersions.

Computational modeling of chemical reactions and interstitial growth and remodeling involving charged solutes and solid-bound molecules

PubMed Central

Nims, Robert J.; Maas, Steve; Weiss, Jeffrey A.

2014-01-01

Mechanobiological processes are rooted in mechanics and chemistry, and such processes may be modeled in a framework that couples their governing equations starting from fundamental principles. In many biological applications, the reactants and products of chemical reactions may be electrically charged, and these charge effects may produce driving forces and constraints that significantly influence outcomes. In this study, a novel formulation and computational implementation are presented for modeling chemical reactions in biological tissues that involve charged solutes and solid-bound molecules within a deformable porous hydrated solid matrix, coupling mechanics with chemistry while accounting for electric charges. The deposition or removal of solid-bound molecules contributes to the growth and remodeling of the solid matrix; in particular, volumetric growth may be driven by Donnan osmotic swelling, resulting from charged molecular species fixed to the solid matrix. This formulation incorporates the state of strain as a state variable in the production rate of chemical reactions, explicitly tying chemistry with mechanics for the purpose of modeling mechanobiology. To achieve these objectives, this treatment identifies the specific theoretical and computational challenges faced in modeling complex systems of interacting neutral and charged constituents while accommodating any number of simultaneous reactions where reactants and products may be modeled explicitly or implicitly. Several finite element verification problems are shown to agree with closed-form analytical solutions. An illustrative tissue engineering analysis demonstrates tissue growth and swelling resulting from the deposition of chondroitin sulfate, a charged solid-bound molecular species. This implementation is released in the open-source program FEBio (www.febio.org). The availability of this framework may be particularly beneficial to optimizing tissue engineering culture systems by examining the influence of nutrient availability on the evolution of inhomogeneous tissue composition and mechanical properties, the evolution of construct dimensions with growth, the influence of solute and solid matrix electric charge on the transport of cytokines, the influence of binding kinetics on transport, the influence of loading on binding kinetics, and the differential growth response to dynamically loaded versus free-swelling culture conditions. PMID:24558059

Computational modeling of chemical reactions and interstitial growth and remodeling involving charged solutes and solid-bound molecules.

PubMed

Ateshian, Gerard A; Nims, Robert J; Maas, Steve; Weiss, Jeffrey A

2014-10-01

Mechanobiological processes are rooted in mechanics and chemistry, and such processes may be modeled in a framework that couples their governing equations starting from fundamental principles. In many biological applications, the reactants and products of chemical reactions may be electrically charged, and these charge effects may produce driving forces and constraints that significantly influence outcomes. In this study, a novel formulation and computational implementation are presented for modeling chemical reactions in biological tissues that involve charged solutes and solid-bound molecules within a deformable porous hydrated solid matrix, coupling mechanics with chemistry while accounting for electric charges. The deposition or removal of solid-bound molecules contributes to the growth and remodeling of the solid matrix; in particular, volumetric growth may be driven by Donnan osmotic swelling, resulting from charged molecular species fixed to the solid matrix. This formulation incorporates the state of strain as a state variable in the production rate of chemical reactions, explicitly tying chemistry with mechanics for the purpose of modeling mechanobiology. To achieve these objectives, this treatment identifies the specific theoretical and computational challenges faced in modeling complex systems of interacting neutral and charged constituents while accommodating any number of simultaneous reactions where reactants and products may be modeled explicitly or implicitly. Several finite element verification problems are shown to agree with closed-form analytical solutions. An illustrative tissue engineering analysis demonstrates tissue growth and swelling resulting from the deposition of chondroitin sulfate, a charged solid-bound molecular species. This implementation is released in the open-source program FEBio ( www.febio.org ). The availability of this framework may be particularly beneficial to optimizing tissue engineering culture systems by examining the influence of nutrient availability on the evolution of inhomogeneous tissue composition and mechanical properties, the evolution of construct dimensions with growth, the influence of solute and solid matrix electric charge on the transport of cytokines, the influence of binding kinetics on transport, the influence of loading on binding kinetics, and the differential growth response to dynamically loaded versus free-swelling culture conditions.

Dynamic analysis of solid propellant grains subjected to ignition pressurization loading

NASA Astrophysics Data System (ADS)

Chyuan, Shiang-Woei

2003-11-01

Traditionally, the transient analysis of solid propellant grains subjected to ignition pressurization loading was not considered, and quasi-elastic-static analysis was widely adopted for structural integrity because the analytical task gets simplified. But it does not mean that the dynamic effect is not useful and could be neglected arbitrarily, and this effect usually plays a very important role for some critical design. In order to simulate the dynamic response for solid rocket motor, a transient finite element model, accompanied by concepts of time-temperature shift principle, reduced integration and thermorheologically simple material assumption, was used. For studying the dynamic response, diverse ignition pressurization loading cases were used and investigated in the present paper. Results show that the dynamic effect is important for structural integrity of solid propellant grains under ignition pressurization loading. Comparing the effective stress of transient analysis and of quasi-elastic-static analysis, one can see that there is an obvious difference between them because of the dynamic effect. From the work of quasi-elastic-static and transient analyses, the dynamic analysis highlighted several areas of interest and a more accurate and reasonable result could be obtained for the engineer.

Batch and multi-step fed-batch enzymatic saccharification of Formiline-pretreated sugarcane bagasse at high solid loadings for high sugar and ethanol titers.

PubMed

Zhao, Xuebing; Dong, Lei; Chen, Liang; Liu, Dehua

2013-05-01

Formiline pretreatment pertains to a biomass fractionation process. In the present work, Formiline-pretreated sugarcane bagasse was hydrolyzed with cellulases by batch and multi-step fed-batch processes at 20% solid loading. For wet pulp, after 144 h incubation with cellulase loading of 10 FPU/g dry solid, fed-batch process obtained ~150 g/L glucose and ~80% glucan conversion, while batch process obtained ~130 g/L glucose with corresponding ~70% glucan conversion. Solid loading could be further increased to 30% for the acetone-dried pulp. By fed-batch hydrolysis of the dried pulp in pH 4.8 buffer solution, glucose concentration could be 247.3±1.6 g/L with corresponding 86.1±0.6% glucan conversion. The enzymatic hydrolyzates could be well converted to ethanol by a subsequent fermentation using Saccharomices cerevisiae with ethanol titer of 60-70 g/L. Batch and fed-batch SSF indicated that Formiline-pretreated substrate showed excellent fermentability. The final ethanol concentration was 80 g/L with corresponding 82.7% of theoretical yield. Copyright © 2012 Elsevier Ltd. All rights reserved.

Water resources and effects of potential surface coal mining on dissolved solids in Hanging Woman Creek basin, southeastern Montana

USGS Publications Warehouse

Cannon, M.R.

1989-01-01

Groundwater resources of the Hanging Woman Creek basin, Montana include Holocene and Pleistocene alluvial aquifers and sandstone , coal, and clinker aquifers in the Paleocene Fort Union Formation. Surface water resources are composed of Hanging Woman Creek, its tributaries, and small stock ponds. Dissolved-solids concentrations in groundwater ranged from 200 to 11,00 mg/L. Generally, concentrations were largest in alluvial aquifers and smallest in clinker aquifers. Near its mouth, Hanging Woman Creek had a median concentration of about 1,800 mg/L. Mining of the 20-foot to 35-foot-thick Anderson coal bed and 3-foot to 16-foot thick Dietz coal bed could increase dissolved-solids concentrations in shallow aquifers and in Hanging Woman Creek because of leaching of soluble minerals from mine spoils. Analysis of saturated-paste extracts from 158 overburden samples indicated that water moving through mine spoils would have a median increase in dissolved-solids concentration of about 3,700 mg/L, resulting in an additional dissolved-solids load to Hanging Woman Creek of about 3.0 tons/day. Hanging Woman Creek near Birney could have an annual post-mining dissolved-solids load of 3,415 tons at median discharge, a 47% increase from pre-mining conditions load. Post-mining concentrations of dissolved solids, at median discharge, could range from 2,380 mg/L in March to 3,940 mg/L in August, compared to mean pre-mining concentrations that ranged from 1,700 mg/L in July, November, and December to 2,060 mg/L in May. Post-mining concentrations and loads in Hanging Woman Creek would be smaller if a smaller area were mined. (USGS)

Tracking spatial variation in river load from Andean highlands to inter-Andean valleys

NASA Astrophysics Data System (ADS)

Tenorio, Gustavo E.; Vanacker, Veerle; Campforts, Benjamin; Álvarez, Lenín; Zhiminaicela, Santiago; Vercruysse, Kim; Molina, Armando; Govers, Gerard

2018-05-01

Mountains play an important role in the denudation of continents and transfer erosion and weathering products to lowlands and oceans. The rates at which erosion and weathering processes take place in mountain regions have a substantial impact on the morphology and biogeochemistry of downstream reaches and lowlands. The controlling factors of physical erosion and chemical weathering and the coupling between the two processes are not yet fully understood. In this study, we report physical erosion and chemical weathering rates for five Andean catchments located in the southern Ecuadorian Andes and investigate their mutual interaction. During a 4-year monitoring period, we sampled river water at biweekly intervals, and we analyzed water samples for major ions and suspended solids. We derived the total annual dissolved, suspended sediment, and ionic loads from the flow frequency curves and adjusted rating curves and used the dissolved and suspended sediment yields as proxies for chemical weathering and erosion rates. In the 4-year period of monitoring, chemical weathering exceeds physical erosion in the high Andean catchments. Whereas physical erosion rates do not exceed 30 t km-2 y-1 in the relict glaciated morphology, chemical weathering rates range between 22 and 59 t km-2 y-1. The variation in chemical weathering is primarily controlled by intrinsic differences in bedrock lithology. Land use has no discernible impact on the weathering rate but leads to a small increase in base cation concentrations because of fertilizer leaching in surface water. When extending our analysis with published data on dissolved and suspended sediment yields from the northern and central Andes, we observe that the river load composition strongly changes in the downstream direction, indicating large heterogeneity of weathering processes and rates within large Andean basins.

Engineering Design of Safe Automobile Front Strut Tower Brace with Predetermined Destruction

NASA Astrophysics Data System (ADS)

Mironenko, R. Ye; Balaev, E. Yu; Blednova, Zh M.

2018-03-01

This paper shows the developed design of an automobile front strut tower brace instantly breakable on reaching a predetermined value impact load, which allows the impact load not to be transferred to the opposite strut. An automobile front strut tower brace with the directed destruction V-shaped element using the SolidWorks and SolidWorks Simulations software complex was developed, designed and analyzed. The obtained data were confirmed experimentally. By changing geometric features of the V-shaped element, it is possible to change the impact load value required for its destruction.

Homogenization-assisted cavitation hybrid rotation extraction and macroporous resin enrichment of dihydroquercetin from Larix gmelinii.

PubMed

Xia, Yu; Wang, Yinhang; Li, Wei; Ma, Chunhui; Liu, Shouxin

2017-12-01

Cavitation hybrid rotation, which was and is still looked upon as an unavoidable nuisance in the flow systems, for extraction processing intensification of active chemical compounds from natural products. In this study, a homogenization-assisted cavitation hybrid rotation extraction method was applied to extract dihydroquercetin (DHQ) from larch (Larix gmelinii) wood root. The extraction parameters were optimized in single factor experiments with the DHQ extraction yields as the response values. The optimum conditions were as follows: number of extractions, three; ethanol volume fraction for the extraction, 60%; liquid-solid ratio for homogenization, 10mL/g; homogenization time, 8min; liquid-solid ratio for cavitation extraction, 9mL/g, and cavitation extraction time, 35min. Under these conditions, the DHQ content in extract was 4.50±0.02mg/g, and the extraction efficiency was higher than those of traditional techniques. Cavitation can be effectively used to improve the extraction rate by increasing the mass transfer rates and possible rupture of cell wall due to formation of microcavities leading to higher product yields with reduced processing time and solvent consumption. After the extraction process, macroporous resin column chromatography was used to concentrate and purify the DHQ. Three resins were selected from fifteen macroporous resins for further investigation of their performance. Among these resins, AB-8 resin exhibited relatively better adsorption capacities and desorption ratios for DHQ. The ethanol volume fraction of the solutions for sample loading and desorption, and flow rates for loading and desorption were optimized for the macroporous resin column chromatography. Copyright © 2017 Elsevier B.V. All rights reserved.

Anaerobic treatment of wastewater with high suspended solids from a bulk drug industry using fixed film reactor (AFFR).

PubMed

Rao, A Gangagni; Naidu, G Venkata; Prasad, K Krishna; Rao, N Chandrasekhar; Mohan, S Venkata; Jetty, Annapurna; Sarma, P N

2004-07-01

Studies are carried out on the treatment of wastewater from a bulk drug industry using an anaerobic fixed film reactor (AFFR) designed and fabricated in the laboratory. The chemical oxygen demand (COD) and total dissolved solids (TDS) of the wastewater are found to be very high with low Biochemical oxygen demand (BOD) to COD ratio and high total suspended solid (TSS) concentration. Acclimatization of seed consortia and start up of the reactor is carried out by directly using the wastewater, which resulted in reducing the period of startup to 30 days. The reactor is studied at different organic loading rates (OLR) and it is found that the optimum OLR is 10 kg COD/m3/day. The wastewater under investigation, which is having considerable quantity of SS, is treated anaerobically without any pretreatment. The COD and BOD of the reactor outlet wastewater are monitored and reduction at steady state and optimum OLR is observed to be 60-70% of COD and 80-90% of BOD. The reactor is subjected to organic shock loads at two different OLR and it is observed that the reactor could withstand shocks and performance could be restored to normalcy at that OLR. The results obtained indicated that AFFR could be used efficiently for the treatment of wastewater from a bulk drug industry having high COD, TDS and TSS. Copyright 2003 Elsevier Ltd.

Anaerobic treatment of wastewater with high suspended solids from a bulk drug industry using fixed film reactor (AFFR).

PubMed

Gangagni Rao, A; Venkata Naidu, G; Krishna Prasad, K; Chandrasekhar Rao, N; Venkata Mohan, S; Jetty, Annapurna; Sarma, P N

2005-01-01

Studies were carried out on the treatment of wastewater from a bulk drug industry using an anaerobic fixed film reactor (AFFR) designed and fabricated in the laboratory. The chemical oxygen demand (COD) and total dissolved solids (TDS) of the wastewater were found to be very high with low biochemical oxygen demand (BOD) to COD ratio and high total suspended solid (TSS) concentration. Acclimatization of seed consortia and startup of the reactor was carried out by directly using the wastewater, which resulted in reducing the period of startup to 30 days. The reactor was studied at different organic loading rates (OLR) and it was found that the optimum OLR was 10 kg COD/m(3)/day. The wastewater under investigation, which had a considerable quantity of SS, was treated anaerobically without any pretreatment. COD and BOD of the reactor outlet wastewater were monitored and at steady state and optimum OLR 60-70% of COD and 80-90% of BOD were removed. The reactor was subjected to organic shock loads at two different OLR and the reaction could withstand the shocks and performance could be restored to normalcy at that OLR. The results obtained indicated that AFFR could be used efficiently for the treatment of wastewater from a bulk drug industry having high COD, TDS and TSS.

Strand Plasticity Governs Fatigue in Colloidal Gels

NASA Astrophysics Data System (ADS)

van Doorn, Jan Maarten; Verweij, Joanne E.; Sprakel, Joris; van der Gucht, Jasper

2018-05-01

The repeated loading of a solid leads to microstructural damage that ultimately results in catastrophic material failure. While posing a major threat to the stability of virtually all materials, the microscopic origins of fatigue, especially for soft solids, remain elusive. Here we explore fatigue in colloidal gels as prototypical inhomogeneous soft solids by combining experiments and computer simulations. Our results reveal how mechanical loading leads to irreversible strand stretching, which builds slack into the network that softens the solid at small strains and causes strain hardening at larger deformations. We thus find that microscopic plasticity governs fatigue at much larger scales. This gives rise to a new picture of fatigue in soft thermal solids and calls for new theoretical descriptions of soft gel mechanics in which local plasticity is taken into account.

In vivo measurement of spinal column viscoelasticity--an animal model.

PubMed

Hult, E; Ekström, L; Kaigle, A; Holm, S; Hansson, T

1995-01-01

The goal of this study was to measure the in vivo viscoelastic response of spinal motion segments loaded in compression using a porcine model. Nine pigs were used in the study. The animals were anaesthetized and, using surgical techniques, four intrapedicular screws were inserted into the vertebrae of the L2-L3 motion segment. A miniaturized servohydraulic exciter capable of compressing the motion segment was mounted on to the screws. In six animals, a loading scheme consisting of 50 N and 100 N of compression, each applied for 10 min, was used. Each loading period was followed by 10 min restitution with zero load. The loading scheme was repeated four times. Three animals were examined for stiffening effects by consecutively repeating eight times 50 N loading for 5 min followed by 5 min restitution with zero load. This loading scheme was repeated using a 100 N load level. The creep-recovery behavior of the motion segment was recorded continuously. Using non-linear regression techniques, the experimental data were used for evaluating the parameters of a three-parameter standard linear solid model. Correlation coefficients of the order of 0.85 or higher were obtained for the three independent parameters of the model. A survey of the data shows that the viscous deformation rate was a function of the load level. Also, repeated loading at 100 N seemed to induce long-lasting changes in the viscoelastic properties of the porcine lumbar motion segment.

A investigation on unixial and quasi-biaxial tensile mechanical properties of aging HTPB propellant under dynamic loading at low temperature

NASA Astrophysics Data System (ADS)

Duan, Leiguang; Wang, Guang; Zhang, Guoxing; Sun, Xinya; Shang, Hehao

2018-06-01

In order to study the uniaxial and quasi-biaxial mechanical properties of aging solid propellants under low temperature and high strain rate, stress-strain curves and tensile fracture surfaces of HTPB propellant were obtained in a wide range of temperature (-30,25 °C) and strain rates (0.4,4.0 and 14.29 s-1), respectively, by means of uniaxial and biaxial tensile tests and electron microscopy scanning on the fracture cross section. The results indicate that the quasi-biaxial tensile mechanical properties of aging HTPB propellant is same as the uniaxial tensile mechanical properties influenced distinctly by temperature and strain rate. With decreasing temperature and increasing strain rate, the mechanical properties gradually strengthen. The damage for HTPB propellant changes from "dehumidification" to grain fracture. The initial elastic modulus E and maximum tensile stress σ of the uniaxial and biaxial tensile increase gradually with decreasing temperature and increasing strain rate, and well present linear-log function relation with strain rate. The ratio of quasi-biaxial and uniaxial stretching under different loading conditions was obtained so that the researchers could predict the quasi-biaxial tensile mechanical properties of the propellant based on the uniaxial test data.

Opportunities to improve the conversion of food waste to lactate: Fine-tuning secondary factors.

PubMed

RedCorn, Raymond; Engelberth, Abigail S

2017-11-01

Extensive research has demonstrated the potential for bioconversion of food waste to lactate, with major emphasis on adjusting temperature, pH, and loading rate of the fermentation. Each of these factors has a significant effect on lactate production; however, additional secondary factors have received little attention. Here we investigate three additional factors where opportunities exist for process improvement: freezing of samples during storage, discontinuous pH control, and holdover of fermentation broth between fermentations. Freezing samples prior to fermentation was shown to reduce the production rate of lactate by 8%, indicating freeze-thaw should be avoided in experiments. Prior work indicated a trade-off in pH control strategies, where discontinuous pH control correlated with higher lactate accumulation while continuous pH control correlated with higher production rate. Here we demonstrate that continuous pH control can achieve both higher lactate accumulation and higher production rate. Finally, holding over fermentation broth was shown to be a simple method to improve production rate (by 18%) at high food waste loading rates (>140 g volatile solids L -1 ) but resulted in lower lactate accumulation (by 17%). The results inform continued process improvements within the waste treatment of food waste through fermentation to lactic acid.

Experimental Analysis of the Role of Fluid Transport Properties in Fluid-Induced Fracture Initiation and Propagation

NASA Astrophysics Data System (ADS)

Boutt, D.; McPherson, B. J.; Cook, B. K.; Goodwin, L. B.; Williams, J. R.; Lee, M. Y.; Patteson, R.

2003-12-01

It is well known that pore fluid pressure fundamentally influences a rock's mechanical response to stress. However, most measures of the mechanical behavior of rock (e.g. shear strength, Young's modulus) do not incorporate, either explicitly or implicitly, pore fluid pressure or transport properties of rock. Current empirical and theoretical criteria that define the amount of stress a given body of rock can support before fracturing also lack a direct connection between fluid transport and mechanical properties. Our research goal is to use laboratory experimental results to elucidate correlations between rock transport properties and fracture behavior under idealized loading conditions. In strongly coupled fluid-solid systems the evolution of the solid framework is influenced by the fluid and vice versa. These couplings often result in changes of the bulk material properties (i.e. permeability and failure strength) with respect to the fluid's ability to move through the solid and the solids ability to transmit momentum. Feedbacks between fluid and solid framework ultimately play key roles in understanding the spatial and temporal evolution of the coupled fluid-solid system. Discretely coupled models of fluid and solid mechanics were developed a priori to design an experimental approach for testing the role of fluid transport parameters in rock fracture. The experimental approach consists of first loading a fluid saturated cylindrical rock specimen under hydrostatic conditions and then applying a differential stress such that the maximum stress is perpendicular to the cylinder long axis. At the beginning of the test the minimum stress and the fluid pressure are dropped at the same time such that the resulting difference in the initial fluid pressure and the final fluid pressure is greater than the final minimum stress. These loading conditions should produce a fluid driven tensile fracture that is perpendicular to the cylinder long axis. Initial analyses using numerical simulations with similar boundary conditions suggest that resulting fracture propagation rates and fracture spacing are controlled by the rocks hydraulic diffusivity. Modeled rocks with higher permeability had fractures with larger apertures, more localized deformation, and greater fracture spacing. Intuitively, these results are consistent with permeability controlling the time required for pressure to come to equilibrium with the new boundary conditions. Finally, more general goals of this research include using these core-scale experimental data and discrete simulation results to calibrate larger-scale, more traditional continuum models of geologic deformation.

Acoustic Measurements of Small Solid Rocket Motor

NASA Technical Reports Server (NTRS)

Vargas, Magda B.; Kenny, R. Jeremy

2010-01-01

Rocket acoustic noise can induce loads and vibration on the vehicle as well as the surrounding structures. Models have been developed to predict these acoustic loads based on scaling existing solid rocket motor data. The NASA Marshall Space Flight Center acoustics team has measured several small solid rocket motors (thrust below 150,000 lbf) to anchor prediction models. This data will provide NASA the capability to predict the acoustic environments and consequent vibro-acoustic response of larger rockets (thrust above 1,000,000 lbf) such as those planned for the NASA Constellation program. This paper presents the methods used to measure acoustic data during the static firing of small solid rocket motors and the trends found in the data.

Implementation of a best management practice (BMP) system for a clay mining facility in Taiwan.

PubMed

Lin, Jen-Yang; Chen, Yen-Chang; Chen, Walter; Lee, Tsu-Chuan; Yu, Shaw L

2006-01-01

The present paper describes the planning and implementation of a best management practice (BMP) system for a clay mining facility in Northern Taiwan. It is a challenge to plan and design BMPs for mitigating the impact of clay mining operations due to the fact that clay mining drainage typically contains very high concentrations of suspended solids (SS), Fe-ions, and [H+] concentrations. In the present study, a field monitoring effort was conducted to collect data for runoff quality and quantity from a clay mining area in Northern Taiwan. A BMP system including holding ponds connected in series was designed and implemented and its pollutant removal performance was assessed. The assessment was based on mass balance computations and an analysis of the relationship between BMP design parameters such as pond depth, detention time, surface loading rate, etc. and the pollutant removal efficiency. Field sampling results showed that the surface-loading rate is exponential related to the removing rate. The results provide the basis for a more comprehensive and efficient BMP implementation plan for clay mining operations.

Effect of Applied Load and Sliding Speed on Tribological Behavior of TiAl-Based Self-Lubricating Composites

NASA Astrophysics Data System (ADS)

Liu, Xiyao; Shen, Qiao; Shi, Xiaoliang; Zou, Jialiang; Huang, Yuchun; Zhang, Ao; Yan, Zhao; Deng, Xiaobin; Yang, Kang

2018-01-01

This article was dedicated to explore the combined lubrication of silver, MoS2 and carbon nanotubes (CNTs) based on the changes in applied loads and sliding speeds. The results showed that the formed lubricating films played the major role in undertaking the equivalent stress, as well as effectively reduced friction resistance and material loss. It led to small friction coefficient and less wear rate at 1.2 m/s. At 1.2 m/s-16 N, an integrated lubricating film containing Ag, CNTs and MoS2 was continuously formed, which well provided the excellent lubricating property, resulting in lower friction coefficient (0.19) and less wear rate (1.56 × 10-5 mm3/N m). The formation of Ag and CNTs enriched islands acted as the bearing areas and played the major role in resisting friction resistance. Meanwhile, solid lubricant MoS2 was enriched in the lubricating film and effectively protected lubricating film from being destroyed, resulting in small friction coefficient and less wear rate at 1.2 m/s-16 N.

Design and Testing of a Breadboard Electrical Power Control Unit for the Fluid Combustion Facility Experiment

NASA Technical Reports Server (NTRS)

Kimnach, Greg L.; Lebron, Ramon C.

1999-01-01

The Fluid Combustion Facility (FCF) Project and the Power Technology Division at the NASA Glenn Research Center (GRC) at Lewis Field in Cleveland, OH along with the Sundstrand Corporation in Rockford, IL are jointly developing an Electrical Power Converter Unit (EPCU) for the Fluid Combustion Facility to be flown on the International Space Station (ISS). The FCF facility experiment contains three racks: A core rack, a combustion rack, and a fluids rack. The EPCU will be used as the power interface to the ISS 120V(sub dc) power distribution system by each FCF experiment rack which requires 28V(sub dc). The EPCU is a modular design which contains three 120V(sub dc)-to-28V(sub dc) full-bridge, power converters rated at 1 kW(sub e) each bus transferring input relays and solid-state, current-limiting input switches, 48 current-limiting, solid-state, output switches; and control and telemetry hardware. The EPCU has all controls required to autonomously share load demand between the power feeds and--if absolutely necessary--shed loads. The EPCU, which maximizes the usage of allocated ISS power and minimizes loss of power to loads, can be paralleled with other EPCUs. This paper overviews the electrical design and operating characteristics of the EPCU and presents test data from the breadboard design.

Enhancing the bioavailability of magnolol in rabbits using melting solid dispersion with polyvinylpyrrolidone.

PubMed

Lin, Shiuan-Pey; Hou, Yu-Chi; Liao, Tzu-Yun; Tsai, Shang-Yuan

2014-03-01

Preparation of magnolol-loaded amorphous solid dispersion was investigated for improving the bioavailability. A solid dispersion of magnolol was prepared with polyvinylpyrrolidone K-30 (PVP) by melting method, and the physical properties were characterized by using differential scanning calorimetry, powder X-ray diffractometry, Fourier transformation-infrared spectroscopy and scanning electron microscope. In addition, dissolution test was also performed. Subsequently, the bioavailability of magnolol pure compound, its physical mixture and solid dispersion were compared in rabbits. The blood samples withdrawn via marginal ear vein at specific time points were assayed by HPLC method. Oral administration of the solid dispersion of magnolol with PVP significantly increased the systemic exposures of magnolol and magnolol sulfates/glucuronides by 80.1% and 142.8%, respectively, compared to those given with magnolol pure compound. Magnolol-loaded amorphous solid dispersion with PVP has demonstrated enhanced bioavailability of magnolol in rabbits.

Lubrication with solids.

NASA Technical Reports Server (NTRS)

Buckley, D. H.; Johnson, R. L.

1972-01-01

Brief discussion of the historical background, variety range, chemistry, physics, and other properties of solid lubricants, and review of their current uses. The widespread use of solid lubricants did not occur until about 1947. At present, they are the object of such interest that a special international conference on their subject was held in 1971. They are used at temperatures beyond the useful range of conventional lubricating oils and greases. Their low volatility provides them with the capability of functioning effectively in vacuum and invites their use in space applications. Their high load carrying ability makes them useful with heavily loaded components. Solid lubricants, however, do lack some of the desirable properties of conventional lubricants. Unlike oils and greases, which have fluidity and can continuously be carried back into contact with lubricated surfaces, solid lubricants, because of their immobility, have finite lives. Also, oils and greases can carry away frictional heat from contacting surfaces, while solid lubricants cannot.

Physicochemical characterization of tacrolimus-loaded solid dispersion with sodium carboxylmethyl cellulose and sodium lauryl sulfate.

PubMed

Park, Young-Joon; Ryu, Dong-Sung; Li, Dong Xun; Quan, Qi Zhe; Oh, Dong Hoon; Kim, Jong Oh; Seo, Youn Gee; Lee, Young-Im; Yong, Chul Soon; Woo, Jong Soo; Choi, Han-Gon

2009-06-01

To develop a novel tacrolimus-loaded solid dispersion with improved solubility, various solid dispersions were prepared with various ratios of water, sodium lauryl sulfate, citric acid and carboxylmethylcellulose-Na using spray drying technique. The physicochemical properties of solid dispersions were investigated using scanning electron microscopy, differential scanning calorimetery and powder X-ray diffraction. Furthermore, their solubility and dissolution were evaluated compared to drug powder. The solid dispersion at the tacrolimus/CMC-Na/sodium lauryl sulfate/citric acid ratio of 3/24/3/0.2 significantly improved the drug solubility and dissolution compared to powder. The scanning electron microscopy result suggested that carriers might be attached to the surface of drug in this solid dispersion. Unlike traditional solid dispersion systems, the crystal form of drug in this solid dispersion could not be converted to amorphous form, which was confirmed by the analysis of DSC and powder X-ray diffraction. Thus, the solid dispersion system with water, sodium lauryl sulfate, citric acid and CMC-Na should be a potential candidate for delivering a poorly water-soluble tacrolimus with enhanced solubility and no convertible crystalline.

Treatment of wastewater containing a large amount of suspended solids by a novel multi-staged UASB reactor.

PubMed

Uemura, S; Harada, H; Ohashi, A; Torimura, S

2005-12-01

Treatment of artificial wastewater containing a large amount of suspended solids comprised of soybean processing waste and pig fodder was studied using a novel multi-staged upflow anaerobic sludge blanket reactor. The reactor consisted of three compartments, each containing a gas solid separator. The wastewater had chemical oxygen demand of approximately 21600 mg l(-1), suspended solids of 12800 mg l(-1), and an ammonia concentration of 945 mg l(-1). A continuous experiment without effluent circulation showed that the multi-staged reactor was not that effective for the treatment of wastewater containing a large amount of suspended solids. However, operation of the reactor with circulation of effluent enabled the reactor to achieve organic removal of 85% and approximately 70% methane conversion at loading rates of between 4.0 to 5.4 kg-chemical oxygen demand per cubic meter per day, meaning that the reactor was more effective when effluent was circulated. Morphological investigation revealed that the crude fiber in the sludge was partially degraded and that it had many small depressions on its surface. Evolved biogas may have become caught in these depressions of the fibers and caused washout of the sludge.

Drawer compacted sand filter: a new and innovative method for on-site grey water treatment.

PubMed

Assayed, Almoayied; Chenoweth, Jonathan; Pedley, Steven

2014-01-01

In this paper, results ofa new sand filter design were presented. The drawer compacted sand filter (DCSF) is a modified design for a sand filter in which the sand layer is broken down into several layers, each of which is 10 cm high and placed in a movable drawer separated by a 10 cm space. A lab-scale DCSF was designed and operated for 330 days fed by synthetic grey water. The response of drawer sand filters to variable hydraulic and organic loading rates (HLR and OLR) in terms of biological oxygen demand (BODs), chemical oxygen demand (COD), total suspended solids (TSS), pH, electrical conductivity and Escherichia coli reductions were evaluated. The HLR was studied by increasing from 72 to 142 L m(-2) day(-1) and OLR was studied by increasing it from 23 to 30 g BOD5 m(-2) day(-1) while keeping the HLR constant at 142 L m(-2) day(-1). Each loading regime was applied for 110 days. Results showed that DCSF was able to remove >90% of organic matter and total suspended solids for all doses. No significant difference was noticed in terms of overall filter efficiency between different loads for all parameters. Significant reduction in BOD5 and COD (P < .05) was noticed after water was drained through the third drawer in all tested loads. The paper concludes that DCSF would be appropriate for use in dense urban areas as its footprint is small and is appropriate for a wide range of users because of its convenience and low maintenance requirements.

Anaerobic rumen SBR for degradation of cellulosic material.

PubMed

Barnes, S P; Keller, J

2004-01-01

Hydrolysis of organic particulates under anaerobic conditions is generally regarded as the rate limiting step in solid digestion processes. Rumen-based ecosystems appear to achieve very high hydrolysis rates for cellulosic organic material. This study aimed at the development and demonstration of an anaerobic sequencing batch reactor (SBR) process operating with a rumen-based microbial inoculum. Fibrous alpha cellulose was used as sole carbon substrate and the use of an SBR operating cycle allowed the utilisation of a high liquid flow rate (hydraulic retention time of 0.67 d) while maintaining a much longer solids retention time of 7 d. Complete mass balances for carbon and nitrogen, as well as COD balancing allowed the full characterisation of the process stoichiometry and kinetics. Elemental analysis of the biomass revealed a composition of C5H4.8O2.4N0.7, which is quite different from other generic biomass compositions used in the literature. The anaerobic rumen SBR was compared with another rumen-based reactor system in the literature which used a continuous filtration process for solid/liquid separation. This comparison showed that the volatile fatty acid production rate from cellulose in the anaerobic SBR was comparable with the performance achieved in the continuous system, although loading, substrate type and media composition were quite different between these two studies. Further evaluation of the anaerobic rumen SBR is required to determine its practical application for other substrates and to demonstrate the scale-up potential of this concept.

Improving the yield from fermentative hydrogen production.

PubMed

Kraemer, Jeremy T; Bagley, David M

2007-05-01

Efforts to increase H(2) yields from fermentative H(2) production include heat treatment of the inoculum, dissolved gas removal, and varying the organic loading rate. Although heat treatment kills methanogens and selects for spore-forming bacteria, the available evidence indicates H(2) yields are not maximized compared to bromoethanesulfonate, iodopropane, or perchloric acid pre-treatments and spore-forming acetogens are not killed. Operational controls (low pH, short solids retention time) can replace heat treatment. Gas sparging increases H(2) yields compared to un-sparged reactors, but no relationship exists between the sparging rate and H(2) yield. Lower sparging rates may improve the H(2) yield with less energy input and product dilution. The reasons why sparging improves H(2) yields are unknown, but recent measurements of dissolved H(2) concentrations during sparging suggest the assumption of decreased inhibition of the H(2)-producing enzymes is unlikely. Significant disagreement exists over the effect of organic loading rate (OLR); some studies show relatively higher OLRs improve H(2) yield while others show the opposite. Discovering the reasons for higher H(2) yields during dissolved gas removal and changes in OLR will help improve H(2) yields.

Molecularly imprinted polymer online solid-phase extraction coupled with high-performance liquid chromatography-UV for the determination of three sulfonamides in pork and chicken.

PubMed

He, Jinxing; Wang, Shuo; Fang, Guozhen; Zhu, Huaping; Zhang, Yan

2008-05-14

A selective imprinted amino-functionalized silica gel sorbent was prepared by combining a surface molecular imprinting technique with a sol-gel process for online solid-phase extraction-HPLC determination of three trace sulfonamides in pork and chicken muscle. The imprinted functionalized silica gel sorbent exhibited selectivity and fast kinetics for the adsorption and desorption of sulfonamides. With a sample loading flow rate of 4 mL min (-1) for 12.5 min, enhancement factors and detection limits for three sulfonamides ( S/ N = 3) were achieved. The precision (RSD) for nine replicate online sorbent extractions of 5 microg L (-1) sulfonamides was less than 4.5%. The sorbent also offered good linearity ( r (2) > 0.99) for online solid-phase extraction of trace levels of sulfonamides. The method was applied to the determination of sulfonamides in pork and chicken muscle samples. The prepared polymer sorbent shows promise for online solid-phase extraction for HPLC determination of trace levels of sulfonamides in pork and chicken samples.

ESTIMATING URBAN WET-WEATHER POLLUTANT LOADING

EPA Science Inventory

This paper presents procedures for estimating pollutant loads in urban watersheds emanating from wet-weather flow discharge. Equations for pollutant loading estimates will focus on the effects of wastewater characteristics, sewer flow carrying velocity, and sewer-solids depositi...

The starting transient of solid propellant rocket motors with high internal gas velocities. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Peretz, A.; Caveny, L. H.; Kuo, K. K.; Summerfield, M.

1973-01-01

A comprehensive analytical model which considers time and space development of the flow field in solid propellant rocket motors with high volumetric loading density is described. The gas dynamics in the motor chamber is governed by a set of hyperbolic partial differential equations, that are coupled with the ignition and flame spreading events, and with the axial variation of mass addition. The flame spreading rate is calculated by successive heating-to-ignition along the propellant surface. Experimental diagnostic studies have been performed with a rectangular window motor (50 cm grain length, 5 cm burning perimeter and 1 cm hydraulic port diameter), using a controllable head-end gaseous igniter. Tests were conducted with AP composite propellant at port-to-throat area ratios of 2.0, 1.5, 1.2, and 1.06, and head-end pressures from 35 to 70 atm. Calculated pressure transients and flame spreading rates are in very good agreement with those measured in the experimental system.

A start-up of psychrophilic anaerobic sequence batch reactor digesting a 35 % total solids feed of dairy manure and wheat straw.

PubMed

Saady, Noori M Cata; Massé, Daniel I

2015-12-01

Zero liquid discharge is currently an objective in livestock manure management to minimize water pollution. This paper reports the start-up phase of a novel psychrophilic (20 °C) dry anaerobic digestion of dairy manure with bedding fed at 35 % total solids and an organic loading rate of 3.0 g total chemical oxygen demand kg(-1) inoculum day(-1) in anaerobic sequence batch reactors. The specific methane (CH4) yield ranged from 165.4 ± 9.8 to 213.9 ± 13.6 NL CH4 kg(-1) volatile solids (VS) with an overall average of 188 ± 17 NL CH4 kg(-1) VS during 11 successive start-up cycles (231 days) and a maximum CH4 production rate of 10.2 ± 0.6 NL CH4 kg(-1) VS day(-1). The inoculum-to-substrate (VS-based) ratio ranged from 4.06 to 4.47. Although methanogenesis proceeded fairly well the hydrolysis seemed to be the rate limiting step. It is possible start up psychrophilic dry anaerobic digestion of cow feces and wheat straw at feed TS of 35 % within 7-10 successive cycles (147-210 days).

Effects of cooling rate on particle rearrangement statistics: Rapidly cooled glasses are more ductile and less reversible.

PubMed

Fan, Meng; Wang, Minglei; Zhang, Kai; Liu, Yanhui; Schroers, Jan; Shattuck, Mark D; O'Hern, Corey S

2017-02-01

Amorphous solids, such as metallic, polymeric, and colloidal glasses, display complex spatiotemporal response to applied deformations. In contrast to crystalline solids, during loading, amorphous solids exhibit a smooth crossover from elastic response to plastic flow. In this study, we investigate the mechanical response of binary Lennard-Jones glasses to athermal, quasistatic pure shear as a function of the cooling rate used to prepare them. We find several key results concerning the connection between strain-induced particle rearrangements and mechanical response. We show that the energy loss per strain dU_{loss}/dγ caused by particle rearrangements for more rapidly cooled glasses is larger than that for slowly cooled glasses. We also find that the cumulative energy loss U_{loss} can be used to predict the ductility of glasses even in the putative linear regime of stress versus strain. U_{loss} increases (and the ratio of shear to bulk moduli decreases) with increasing cooling rate, indicating enhanced ductility. In addition, we characterized the degree of reversibility of particle motion during a single shear cycle. We find that irreversible particle motion occurs even in the linear regime of stress versus strain. However, slowly cooled glasses, which undergo smaller rearrangements, are more reversible during a single shear cycle than rapidly cooled glasses. Thus, we show that more ductile glasses are also less reversible.

Calculating salt loads to Great Salt Lake and the associated uncertainties for water year 2013; updating a 48 year old standard

USGS Publications Warehouse

Shope, Christopher L.; Angeroth, Cory E.

2015-01-01

Effective management of surface waters requires a robust understanding of spatiotemporal constituent loadings from upstream sources and the uncertainty associated with these estimates. We compared the total dissolved solids loading into the Great Salt Lake (GSL) for water year 2013 with estimates of previously sampled periods in the early 1960s.We also provide updated results on GSL loading, quantitatively bounded by sampling uncertainties, which are useful for current and future management efforts. Our statistical loading results were more accurate than those from simple regression models. Our results indicate that TDS loading to the GSL in water year 2013 was 14.6 million metric tons with uncertainty ranging from 2.8 to 46.3 million metric tons, which varies greatly from previous regression estimates for water year 1964 of 2.7 million metric tons. Results also indicate that locations with increased sampling frequency are correlated with decreasing confidence intervals. Because time is incorporated into the LOADEST models, discrepancies are largely expected to be a function of temporally lagged salt storage delivery to the GSL associated with terrestrial and in-stream processes. By incorporating temporally variable estimates and statistically derived uncertainty of these estimates,we have provided quantifiable variability in the annual estimates of dissolved solids loading into the GSL. Further, our results support the need for increased monitoring of dissolved solids loading into saline lakes like the GSL by demonstrating the uncertainty associated with different levels of sampling frequency.

Effect of load on the tribological properties of hypereutectic Al-Si alloy under boundary lubrication conditions

NASA Astrophysics Data System (ADS)

Kumar, Parveen; Wani, M. F.

2017-11-01

Researchers reported that the IC engine components (piston, cylinder liner etc) fail due to the friction losses (~45%) and wear losses (~25-40%). So the demand of light weight, low friction and wear resistance alloys increases day by day, which reduces the emission and increases the efficiency of the IC engine. In this connection, tribological tests on hypereutectic Al-25Si alloy were performed using a ball-on-disk configuration under dry and lubricated sliding conditions. Hypereutectic Al-25Si alloy was prepared by rapid solidification process with T6 condition. T6 condition improves the friction, wear and mechanical properties of the alloy. Friction coefficient and wear rate of the alloy was measured under high loads ranging from 100 to 300 N. It was found that the friction coefficient (COF) and wear rate of hypereutectic Al-25Si alloy/steel tribo pair increased with increase in load. Significant reduction in COF and wear rate was accomplished with SAE20W50 engine oil and Si particles act as solid lubricant. Optical microscope, 3D surface profilometer and scanning electron microscope (SEM) coupled with an energy dispersive spectrometer (EDS) were used for characterization the worn surface morphologies. The morphology, size and distribution of high Si particles due to its fabrication process caused the improvements in COF and wear rate under lubricated conditions. Adhesive wear, abrasive wear and plastic deformation acted as the dominant wear mechanism for hypereutectic Al-25Si alloy.

Comparisons Between Stability Prediction and Measurements for the Reusable Solid Rocket Motor

NASA Technical Reports Server (NTRS)

Fischbach, Sean R.; Kenny, R. Jeremy

2010-01-01

The Space Transportation System has used the solid rocket boosters for lift-off and ascent propulsion over the history of the program. Part of the structural loads assessment of the assembled vehicle is the contribution due to solid rocket booster thrust oscillations. These thrust oscillations are a consequence of internal motor pressure oscillations active during operation. Understanding of these pressure oscillations is key to predicting the subsequent thrust oscillations and vehicle loading. The pressure oscillation characteristics of the Reusable Solid Rocket Motor (RSRM) design are reviewed in this work. Dynamic pressure data from the static test and flight history are shown, with emphasis on amplitude, frequency, and timing of the oscillations. Physical mechanisms that cause these oscillations are described by comparing data observations to predictions made by the Solid Stability Prediction (SSP) code.

Application of solid-acid catalyst and marine macro-algae Gracilaria verrucosa to production of fermentable sugars.

PubMed

Jeong, Gwi-Taek; Kim, Sung-Koo; Park, Don-Hee

2015-04-01

In this study, the hydrolysis of marine macro-algae Gracilaria verrucosa with a solid-acid catalyst was investigated. To optimize the hydrolysis, four reaction factors, including liquid-to-solid ratio, catalyst loading, reaction temperature, and reaction time, were investigated. In the results, the highest total reducing sugar (TRS) yield, 61 g/L (51.9%), was obtained under the following conditions: 1:7.5 solid-to-liquid ratio, 15% (w/v) catalyst loading, 140 °C reaction temperature, and 150 min reaction time. Under these conditions, 10.7 g/L of 5-HMF and 2.5 g/L of levulinic acid (LA) were generated. The application of solid-acid catalyst and marine macro-algae resources shows a very high potential for production of fermentable sugars. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sources and sinks of filtered total mercury and concentrations of total mercury of solids and of filtered methylmercury, Sinclair Inlet, Kitsap County, Washington, 2007-10

USGS Publications Warehouse

Paulson, Anthony J.; Dinicola, Richard S.; Noble, Marlene A.; Wagner, Richard J.; Huffman, Raegan L.; Moran, Patrick W.; DeWild, John F.

2012-01-01

The majority of filtered total mercury in the marine water of Sinclair Inlet originates from salt water flowing from Puget Sound. About 420 grams of filtered total mercury are added to Sinclair Inlet each year from atmospheric, terrestrial, and sedimentary sources, which has increased filtered total mercury concentrations in Sinclair Inlet (0.33 nanograms per liter) to concentrations greater than those of the Puget Sound (0.2 nanograms per liter). The category with the largest loading of filtered total mercury to Sinclair Inlet included diffusion of porewaters from marine sediment to the water column of Sinclair Inlet and discharge through the largest stormwater drain on the Bremerton naval complex, Bremerton, Washington. However, few data are available to estimate porewater and stormwater releases with any certainty. The release from the stormwater drain does not originate from overland flow of stormwater. Rather total mercury on soils is extracted by the chloride ions in seawater as the stormwater is drained and adjacent soils are flushed with seawater by tidal pumping. Filtered total mercury released by an unknown freshwater mechanism also was observed in the stormwater flowing through this drain. Direct atmospheric deposition on the Sinclair Inlet, freshwater discharge from creek and stormwater basins draining into Sinclair Inlet, and saline discharges from the dry dock sumps of the naval complex are included in the next largest loading category of sources of filtered total mercury. Individual discharges from a municipal wastewater treatment plant and from the industrial steam plant of the naval complex constituted the loading category with the third largest loadings. Stormwater discharge from the shipyard portion of the naval complex and groundwater discharge from the base are included in the loading category with the smallest loading of filtered total mercury. Presently, the origins of the solids depositing to the sediment of Sinclair Inlet are uncertain, and consequently, concentrations of sediments can be qualitatively compared only to total mercury concentrations of solids suspended in the water column. Concentrations of total mercury of suspended solids from creeks, stormwater, and even wastewater effluent discharging into greater Sinclair Inlet were comparable to concentrations of solids suspended in the water column of Sinclair Inlet. Concentrations of total mercury of suspended solids were significantly lower than those of marine bed sediment of Sinclair Inlet; these suspended solids have been shown to settle in Sinclair Inlet. The settling of suspended solids in the greater Sinclair Inlet and in Operable Unit B Marine of the naval complex likely will result in lower concentrations of total mercury in sediments. Such a decrease in total mercury concentrations was observed in the sediment of Operable Unit B Marine in 2010. However, total mercury concentrations of solids discharged from several sources from the Bremerton naval complex were higher than concentrations in sediment collected from Operable Unit B Marine. The combined loading of solids from these sources is small compared to the amount of solids depositing in OU B Marine. However, total mercury concentration in sediment collected at a monitoring station just offshore one of these sources, the largest stormwater drain on the Bremerton naval complex, increased considerably in 2010. Low methylmercury concentrations were detected in groundwater, stormwater, and effluents discharged from the Bremerton naval complex. The highest methylmercury concentrations were measured in the porewaters of highly reducing marine sediment in greater Sinclair Inlet. The marine sediment collected off the largest stormwater drain contained low concentrations of methylmercury in porewater because these sediments were not highly reducing.

Propulsion and Power Rapid Response R&D Support Delivery Order 0041: Power Dense Solid Oxide Fuel Cell Systems: High Performance, High Power Density Solid Oxide Fuel Cells - Materials and Load Control

DTIC Science & Technology

2008-12-01

respectively. 2.3.1.2 Brushless DC Motor Brushless direct current ( BLDC ) motors feature high efficiency, ease of control , and astonishingly high power...modeling purposes, we ignore the modeling complexity of the BLDC controller and treat the motor and controller “as commutated”, i.e. we assume the...High Performance, High Power Density Solid Oxide Fuel Cells− Materials and Load Control Stephen W. Sofie, Steven R. Shaw, Peter A. Lindahl, and Lee H

Addressing the Interface Issues in All-Solid-State Bulk-Type Lithium Ion Battery via an All-Composite Approach.

PubMed

Chen, Ru-Jun; Zhang, Yi-Bo; Liu, Ting; Xu, Bing-Qing; Lin, Yuan-Hua; Nan, Ce-Wen; Shen, Yang

2017-03-22

All-solid-state bulk-type lithium ion batteries (LIBs) are considered ultimate solutions to the safety issues associated with conventional LIBs using flammable liquid electrolyte. The development of bulk-type all-solid-state LIBs has been hindered by the low loading of active cathode materials, hence low specific surface capacity, and by the high interface resistance, which results in low rate and cyclic performance. In this contribution, we propose and demonstrate a synergistic all-composite approach to fabricating flexible all-solid-state LIBs. PEO-based composite cathode layers (filled with LiFePO 4 particles) of ∼300 μm in thickness and composite electrolyte layers (filled with Al-LLZTO particles) are stacked layer-by-layer with lithium foils as negative layer and hot-pressed into a monolithic all-solid-state LIB. The flexible LIB delivers a high specific discharge capacity of 155 mAh/g, which corresponds to an ultrahigh surface capacity of 10.8 mAh/cm 2 , exhibits excellent capacity retention up to at least 10 cycles and could work properly under harsh operating conditions such as bending or being sectioned into pieces. The all-composite approach is favorable for improving both mesoscopic and microscopic interfaces inside the all-solid-state LIB and may provide a new toolbox for design and fabrication of all-solid-state LIBs.

Space Shuttle Projects

NASA Image and Video Library

1987-07-01

A forward segment is being lowered into the Transient Pressure Test Article (TPTA) test stand at the Marshall Space Flight Center (MSFC) east test area. The TPTA test stand, 14-feet wide, 27-feet long, and 33-feet high, was built in 1987 to provide data to verify the sealing capability of the redesign solid rocket motor (SRM) field and nozzle joints. The test facility applies pressure, temperature, and external loads to a short stack of solid rocket motor hardware. The simulated SRM ignition pressure and temperature transients are achieved by firing a small amount of specially configured solid propellant. The pressure transient is synchronized with external programmable dynamic loads that simulate lift off loads at the external tank attach points. Approximately one million pounds of dead weight on top of the test article simulates the weight of the other Shuttle elements.

Space Shuttle Projects

NASA Image and Video Library

1987-07-01

A forward segment is being lowered into the Transient Pressure Test Article (TPTA) test stand at thw Marshall Space Flight Center (MSFC) east test area. The TPTA test stand, 14-feet wide, 27-feet long, and 33-feet high, was built in 1987 to provide data to verify the sealing capability of the redesign solid rocket motor (SRM) field and nozzle joints. The test facility applies pressure, temperature, and external loads to a short stack of solid rocket motor hardware. The simulated SRM ignition pressure and temperature transients are achieved by firing a small amount of specially configured solid propellant. The pressure transient is synchronized with external programmable dynamic loads that simulate lift off loads at the external tank attach points. Approximately one million pounds of dead weight on top of the test article simulates the weight of the other Shuttle elements.

Shock Mitigation in Open-Celled TiNi Foams

NASA Astrophysics Data System (ADS)

Jardine, A. Peter

2018-05-01

High-energy shock events generated by impacts are effectively mitigated by Nitinol materials. Initial evidence of this capability was suggested by the dramatically superior cavitation-erosion performance of Nitinol coatings made by plasma spray processes, over steels and brasses. A fast acting hysteretic stress-strain response mechanism was proposed to explain this result, transforming the shock energy into heat. Extending this work to bulk TiNi, dynamic load characterization using Split Rod Hopkinson Bar techniques on solid porous TiNi confirmed that the mechanical response to high strain rates below 4200 s-1 were indeed hysteretic. This paper reports on dynamical load characterization on TiNi foams made by Self-Propagating High-Temperature Synthesis (SHS) using Split Rod Hopkinson Bar and gas-gun impact characterization to compare these foams to alternative materials. This work verified that SHS-derived TiNi foams were indeed hysteretic at strain rates from 180 to 2300 s-1. In addition, Shock Spectrum Analysis demonstrated that TiNi foams were very effective in mitigating the shock spectrum range below 5 kHz, and that increasing porosity increased the amount of shock attenuation in that spectral range. Finally under impact loading, 55% porous TiNi foams were a factor of 7 superior to steel and a factor of 4 better than Al 6061 or Cu in mitigating peak g-loads and this attenuation improved with bilayer structures of 57 and 73% porous TiNi foam article.

Intervertebral disc response to cyclic loading--an animal model.

PubMed

Ekström, L; Kaigle, A; Hult, E; Holm, S; Rostedt, M; Hansson, T

1996-01-01

The viscoelastic response of a lumbar motion segment loaded in cyclic compression was studied in an in vivo porcine model (N = 7). Using surgical techniques, a miniaturized servohydraulic exciter was attached to the L2-L3 motion segment via pedicle fixation. A dynamic loading scheme was implemented, which consisted of one hour of sinusoidal vibration at 5 Hz, 50 N peak load, followed by one hour of restitution at zero load and one hour of sinusoidal vibration at 5 Hz, 100 N peak load. The force and displacement responses of the motion segment were sampled at 25 Hz. The experimental data were used for evaluating the parameters of two viscoelastic models: a standard linear solid model (three-parameter) and a linear Burger's fluid model (four-parameter). In this study, the creep behaviour under sinusoidal vibration at 5 Hz closely resembled the creep behaviour under static loading observed in previous studies. Expanding the three-parameter solid model into a four-parameter fluid model made it possible to separate out a progressive linear displacement term. This deformation was not fully recovered during restitution and is therefore an indication of a specific effect caused by the cyclic loading. High variability was observed in the parameters determined from the 50 N experimental data, particularly for the elastic modulus E1. However, at the 100 N load level, significant differences between the models were found. Both models accurately predicted the creep response under the first 800 s of 100 N loading, as displayed by mean absolute errors for the calculated deformation data from the experimental data of 1.26 and 0.97 percent for the solid and fluid models respectively. The linear Burger's fluid model, however, yielded superior predictions particularly for the initial elastic response.

Contact solution algorithms

NASA Technical Reports Server (NTRS)

Tielking, John T.

1989-01-01

Two algorithms for obtaining static contact solutions are described in this presentation. Although they were derived for contact problems involving specific structures (a tire and a solid rubber cylinder), they are sufficiently general to be applied to other shell-of-revolution and solid-body contact problems. The shell-of-revolution contact algorithm is a method of obtaining a point load influence coefficient matrix for the portion of shell surface that is expected to carry a contact load. If the shell is sufficiently linear with respect to contact loading, a single influence coefficient matrix can be used to obtain a good approximation of the contact pressure distribution. Otherwise, the matrix will be updated to reflect nonlinear load-deflection behavior. The solid-body contact algorithm utilizes a Lagrange multiplier to include the contact constraint in a potential energy functional. The solution is found by applying the principle of minimum potential energy. The Lagrange multiplier is identified as the contact load resultant for a specific deflection. At present, only frictionless contact solutions have been obtained with these algorithms. A sliding tread element has been developed to calculate friction shear force in the contact region of the rolling shell-of-revolution tire model.

Applications of tribology to determine attrition by wear of particulate solids in CFB systems

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

Bayham, Samuel C.; Breault, Ronald; Monazam, Esmail

In recent years, much attention has been focused on the development of novel technologies for carbon capture and chemicals production that utilize a circulating fluidized bed (CFB) configuration; examples include chemical looping combustion and circulation of temperature swing adsorbents in a CFB configuration for CO 2 capture. A major uncertainty in determining the economic feasibility of these technologies is the required solids makeup rate, which, among other factors, is due to impact and wear attrition at various locations, including standpipes, cyclones, and the gas jets in fluid beds. While correlations have been developed that estimate the attrition rates at thesemore » areas, these correlations are dependent on constants that are uncertain without extensive experiment in the corresponding unit operation. Thus, it is difficult to determine the attrition rate a priori without performing extensive experiments on the materials or scaling up entirely. In this work, the authors outline a methodology for predictive attrition based on fundamental material properties from fields of tribology—specifically, the study of wear—to the knowledge of forces and sliding distances determined from hydrodynamic models to develop basic attrition models for novel CFB systems. The equations are derived for the standpipe and cyclone, which are common components found in CFBs, and the cyclone equation is compared to experimental data of attrition in the literature. The cyclone equation derived in this work results in an abrasion rate based on (1) material properties such as particle density and hardness, (2) inlet velocity, and (3) cyclone geometry. According to this equation, increasing the diameter of the cyclone and the solids inlet velocity tends to increase the rate of abrasion of the catalyst, while decreasing the hardness increases the abrasion rate. The functionality of the increasing attrition rate with velocity increase implies that increasing the efficiency of the cyclone may also increase the attrition rate via abrasion. With modifications to the severity coefficient term to include the solids loading, the cyclone equation derived in this work fits data from Reppenhagen and Werther with a coefficient of determination (R2) of 92%.« less

Applications of tribology to determine attrition by wear of particulate solids in CFB systems

DOE PAGES

Bayham, Samuel C.; Breault, Ronald; Monazam, Esmail

2016-11-03

In recent years, much attention has been focused on the development of novel technologies for carbon capture and chemicals production that utilize a circulating fluidized bed (CFB) configuration; examples include chemical looping combustion and circulation of temperature swing adsorbents in a CFB configuration for CO 2 capture. A major uncertainty in determining the economic feasibility of these technologies is the required solids makeup rate, which, among other factors, is due to impact and wear attrition at various locations, including standpipes, cyclones, and the gas jets in fluid beds. While correlations have been developed that estimate the attrition rates at thesemore » areas, these correlations are dependent on constants that are uncertain without extensive experiment in the corresponding unit operation. Thus, it is difficult to determine the attrition rate a priori without performing extensive experiments on the materials or scaling up entirely. In this work, the authors outline a methodology for predictive attrition based on fundamental material properties from fields of tribology—specifically, the study of wear—to the knowledge of forces and sliding distances determined from hydrodynamic models to develop basic attrition models for novel CFB systems. The equations are derived for the standpipe and cyclone, which are common components found in CFBs, and the cyclone equation is compared to experimental data of attrition in the literature. The cyclone equation derived in this work results in an abrasion rate based on (1) material properties such as particle density and hardness, (2) inlet velocity, and (3) cyclone geometry. According to this equation, increasing the diameter of the cyclone and the solids inlet velocity tends to increase the rate of abrasion of the catalyst, while decreasing the hardness increases the abrasion rate. The functionality of the increasing attrition rate with velocity increase implies that increasing the efficiency of the cyclone may also increase the attrition rate via abrasion. With modifications to the severity coefficient term to include the solids loading, the cyclone equation derived in this work fits data from Reppenhagen and Werther with a coefficient of determination (R2) of 92%.« less

Influence of drug load on dissolution behavior of tablets containing a poorly water-soluble drug: estimation of the percolation threshold.

PubMed

Wenzel, Tim; Stillhart, Cordula; Kleinebudde, Peter; Szepes, Anikó

2017-08-01

Drug load plays an important role in the development of solid dosage forms, since it can significantly influence both processability and final product properties. The percolation threshold of the active pharmaceutical ingredient (API) corresponds to a critical concentration, above which an abrupt change in drug product characteristics can occur. The objective of this study was to identify the percolation threshold of a poorly water-soluble drug with regard to the dissolution behavior from immediate release tablets. The influence of the API particle size on the percolation threshold was also studied. Formulations with increasing drug loads were manufactured via roll compaction using constant process parameters and subsequent tableting. Drug dissolution was investigated in biorelevant medium. The percolation threshold was estimated via a model dependent and a model independent method based on the dissolution data. The intragranular concentration of mefenamic acid had a significant effect on granules and tablet characteristics, such as particle size distribution, compactibility and tablet disintegration. Increasing the intragranular drug concentration of the tablets resulted in lower dissolution rates. A percolation threshold of approximately 20% v/v could be determined for both particle sizes of the API above which an abrupt decrease of the dissolution rate occurred. However, the increasing drug load had a more pronounced effect on dissolution rate of tablets containing the micronized API, which can be attributed to the high agglomeration tendency of micronized substances during manufacturing steps, such as roll compaction and tableting. Both methods that were applied for the estimation of percolation threshold provided comparable values.

A long-term bench-scale investigation of permanganate consumption by aquifer materials.

PubMed

Xu, Xiuyuan; Thomson, Neil R

2009-11-20

In situ chemical oxidation (ISCO) applications using permanganate involve the injection or release of permanganate into the subsurface to destroy various target contaminants. Naturally occurring reduced components associated with aquifer materials can exert a significant oxidant demand thereby reducing the amount of permanganate available for the destruction of contaminants as well as reducing the overall rate of oxidation. Quantification of this natural oxidant demand (NOD) is a requirement for site-specific assessment and the design of cost-effective oxidant delivery systems. To further our understanding of the interaction between permanganate and aquifer materials, aerobic and anaerobic aquifer materials from eight representative sites throughout North America were tested in a series of systematic bench-scale experiments. Various permanganate to aquifer solids mass loading ratios at different initial permanganate concentrations in well-mixed batch reactors were monitored for >300 days. All NOD temporal profiles demonstrated an initial fast consumption rate followed by a persistent slower consumption rate. The data generated show that the mass loading ratio, the initial permanganate concentration, and the nature and quantity of reduced aquifer material species are the main factors controlling permanganate consumption rates. A higher initial permanganate concentration or a larger mass loading ratio produced a larger fast NOD consumption rate and generated a corresponding higher maximum NOD value. Hence, both the NOD temporal profile and the maximum NOD are not single-valued but are heavily dependent on the experimental conditions. Predictive relationships were developed to estimate the maximum NOD and the NOD at 7 days based on aquifer material properties. The concentration of manganese oxides deposited on the aquifer solids was highly correlated with the mass of permanganate consumed suggesting that passivation of NOD reaction sites occurred due to the formation of manganese oxide coating on the grains. A long-term NOD kinetic model was developed assuming a single fast and slow reacting oxidizable aquifer material species, passivation of NOD reaction sites, and the presence of an autocatalytic reaction. The developed model was able to successfully capture the observed NOD temporal profiles, and can be used to estimate in situ NOD behavior using batch reactor experimental data. The use of batch tests to provide data representative of in situ conditions should be used with caution.

Testing of the Engineering Model Electrical Power Control Unit for the Fluids and Combustion Facility

NASA Technical Reports Server (NTRS)

Kimnach, Greg L.; Lebron, Ramon C.; Fox, David A.

1999-01-01

The John H. Glenn Research Center at Lewis Field (GRC) in Cleveland, OH and the Sundstrand Corporation in Rockford, IL have designed and developed an Engineering Model (EM) Electrical Power Control Unit (EPCU) for the Fluids Combustion Facility, (FCF) experiments to be flown on the International Space Station (ISS). The EPCU will be used as the power interface to the ISS power distribution system for the FCF's space experiments'test and telemetry hardware. Furthermore. it is proposed to be the common power interface for all experiments. The EPCU is a three kilowatt 12OVdc-to-28Vdc converter utilizing three independent Power Converter Units (PCUs), each rated at 1kWe (36Adc @ 28Vdc) which are paralleled and synchronized. Each converter may be fed from one of two ISS power channels. The 28Vdc loads are connected to the EPCU output via 48 solid-state and current-limiting switches, rated at 4Adc each. These switches may be paralleled to supply any given load up to the 108Adc normal operational limit of the paralleled converters. The EPCU was designed in this manner to maximize allocated-power utilization. to shed loads autonomously, to provide fault tolerance. and to provide a flexible power converter and control module to meet various ISS load demands. Tests of the EPCU in the Power Systems Facility testbed at GRC reveal that the overall converted-power efficiency, is approximately 89% with a nominal-input voltage of 12OVdc and a total load in the range of 4O% to 110% rated 28Vdc load. (The PCUs alone have an efficiency of approximately 94.5%). Furthermore, the EM unit passed all flight-qualification level (and beyond) vibration tests, passed ISS EMI (conducted, radiated. and susceptibility) requirements. successfully operated for extended periods in a thermal/vacuum chamber, was integrated with a proto-flight experiment and passed all stability and functional requirements.

40 CFR 60.251 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... continuously monitor relative particulate matter loadings. (c) Bituminous coal means solid fossil fuel... units constructed, reconstructed, or modified on or before May 27, 2009, all solid fossil fuels... § 60.17). (2) For units constructed, reconstructed, or modified after May 27, 2009, all solid fossil...

40 CFR 60.251 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... continuously monitor relative particulate matter loadings. (c) Bituminous coal means solid fossil fuel... units constructed, reconstructed, or modified on or before May 27, 2009, all solid fossil fuels... § 60.17). (2) For units constructed, reconstructed, or modified after May 27, 2009, all solid fossil...

40 CFR 60.251 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... continuously monitor relative particulate matter loadings. (c) Bituminous coal means solid fossil fuel... units constructed, reconstructed, or modified on or before May 27, 2009, all solid fossil fuels... § 60.17). (2) For units constructed, reconstructed, or modified after May 27, 2009, all solid fossil...

40 CFR 60.251 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... continuously monitor relative particulate matter loadings. (c) Bituminous coal means solid fossil fuel... units constructed, reconstructed, or modified on or before May 27, 2009, all solid fossil fuels... § 60.17). (2) For units constructed, reconstructed, or modified after May 27, 2009, all solid fossil...

40 CFR 60.251 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... continuously monitor relative particulate matter loadings. (c) Bituminous coal means solid fossil fuel... units constructed, reconstructed, or modified on or before May 27, 2009, all solid fossil fuels... § 60.17). (2) For units constructed, reconstructed, or modified after May 27, 2009, all solid fossil...

Spatially referenced statistical assessment of dissolved-solids load sources and transport in streams of the Upper Colorado River Basin

USGS Publications Warehouse

Kenney, Terry A.; Gerner, Steven J.; Buto, Susan G.; Spangler, Lawrence E.

2009-01-01

The Upper Colorado River Basin (UCRB) discharges more than 6 million tons of dissolved solids annually, about 40 to 45 percent of which are attributed to agricultural activities. The U.S. Department of the Interior estimates economic damages related to salinity in excess of $330 million annually in the Colorado River Basin. Salinity in the UCRB, as measured by dissolved-solids load and concentration, has been studied extensively during the past century. Over this period, a solid conceptual understanding of the sources and transport mechanisms of dissolved solids in the basin has been developed. This conceptual understanding was incorporated into the U.S. Geological Survey Spatially Referenced Regressions on Watershed Attributes (SPARROW) surface-water quality model to examine statistically the dissolved-solids supply and transport within the UCRB. Geologic and agricultural sources of dissolved solids in the UCRB were defined and represented in the model. On the basis of climatic and hydrologic conditions along with data availability, water year 1991 was selected for examination with SPARROW. Dissolved-solids loads for 218 monitoring sites were used to calibrate a dissolved-solids SPARROW model for the UCRB. The calibrated model generally captures the transport mechanisms that deliver dissolved solids to streams of the UCRB as evidenced by R2 and yield R2 values of 0.98 and 0.71, respectively. Model prediction error is approximated at 51 percent. Model results indicate that of the seven geologic source groups, the high-yield sedimentary Mesozoic rocks have the largest yield of dissolved solids, about 41.9 tons per square mile (tons/mi2). Irrigated sedimentary-clastic Mesozoic lands have an estimated yield of 1,180 tons/mi2, and irrigated sedimentary-clastic Tertiary lands have an estimated yield of 662 tons/mi2. Coefficients estimated for the seven landscape transport characteristics seem to agree well with the conceptual understanding of the role they play in the delivery of dissolved solids to streams in the UCRB. Predictions of dissolved-solids loads were generated for more than 10,000 stream reaches of the stream network defined in the UCRB. From these estimates, the downstream accumulation of dissolved solids, including natural and agricultural components, were examined in selected rivers. Contributions from each of the 11 dissolved-solids sources were also examined at select locations in the Grand, Green, and San Juan Divisions of the UCRB. At the downstream boundary of the UCRB, the Colorado River at Lees Ferry, Arizona, monitoring site, the dissolved-solids contribution of irrigated agricultural lands and natural sources were about 45 and 57 percent, respectively. Finally, model predictions, including the contributions of natural and agricultural sources for selected locations in the UCRB, were compared with results from two previous studies.

Effects of drug-carrier interactions on drug dissolution from binary and ternary matrices

NASA Astrophysics Data System (ADS)

Iqbal, Zafar

For nearly five decades, pharmaceutical researchers have studied solid solutions of drugs in polymers as a potential means to enhance the dissolution of drugs with poor aqueous solubility. This has become of greater importance in recent years because most new potential drug compounds (new chemical entities) exhibit poor water solubility and present great challenges to scientists who must design dosage forms from which the drugs are bioavailable. During the formulation of a solid solution, the drug undergoes physical but not chemical alterations that increase its chemical potential in the formulation relative to that of the pure drug in its stable form. This increased chemical potential is responsible for enhanced dissolution as well as physical instabilities, such as amorphous to crystalline conversions and precipitation within the solid state. The chemical potential is derived from the Gibbs free energy, so it is reasonable to explain the behavior of solid solution systems in terms of thermodynamics. Solid solutions and dispersions have been extensively studied by pharmaceutical scientists, both with regard to manufacturing aspects and the proposal of various models in attempts to explain the physical bases for how these systems work. Recently, Dave and Bellantone proposed a model based on the thermodynamic changes resulting from the formulation of binary solid solutions of a drug in the polymer PVP. Their model introduced a modification of the F-H theory, which was used to quantify the drug-polymer interaction energies and calculate the entropy of mixing of the drug and polymer. In this work, the model of Dave and Bellantone was extended to include three-component systems, consisting of one drug mixed in a carrier matrix consisting of mixture of two polymers or a polymer and a surfactant. For this research, solid solutions were formed using various drug weight fractions in the formulations. The study focused on the following points: (1) Prepare solid solution formulations and perform appropriate physical characterizations. (2) Characterize the increase in drug dissolution rates resulting from solid solution formulations. (3) Relate the initial dissolution rates to the drug solubility. (4) Explain the solubility enhancement from solid solution dosage in terms of the drug polymer interactions using the extended thermodynamic model. Two poorly water soluble drugs, levonorgestrel (LEVO) and ethinyl estradiol (EE) were formulated in seven solid solution preparations comprised of four carrier systems. Materials used as carriers included various combinations of the polymers PVP K-30, Copovidone (COP), Poloxamer 182, and the surfactant TweenRTM 20. Additionally, ibuprofen (IBU) was used in three formulations consisting of various combinations of PVP K-30, Copovidone and TweenRTM 20. Formulations with various drug weight fractions (0.5%--30%) were prepared using the solvent evaporation technique. Each formulation was tested for dissolution using intrinsic dissolution apparatus (USP). The solid solutions were compressed into tablets into the sample die that maintained a constant surface area during the dissolution process. DSC, XRD and NIRS scans identified that the crystalline peaks of the drug disappeared with the addition of the polymer for all ratios of EE, indicating the formation of solid solutions (to within the limits of detection of the equipment). This was also observed for the LEVO dispersions up to 10% drug loading. At higher drug loading, solutions were formed but some small degree crystallinity was also present. For each experiment, the initial dissolution rates were obtained from the slope of the mass dissolved vs. time plots taken at early times, and volume normalized initial dissolution rates RV were calculated by dividing the initial dissolution rate by the volume fraction of the drug in the formulation. Comparison of the RV values for the various formulations with a reference RV (typically that of the pure drug or of the formulation with the highest polymer content) allowed calculation of relative volume normalized dissolution rates (RNV). The various RNV were used in the thermodynamic model for data analyses and to determine the interactions between the drug and carrier molecules. It was generally seen that RNV increased with decreased drug fraction, and was adequately modeled by the equations derived from the extended thermodynamic model. It was concluded that the model proposed for the binary and ternary systems successfully represented the mechanism of drug-polymer interaction and the energy changes taken place within the dispersion systems. The dissolution data analysis and subsequent understanding of physical modifications in the dispersion systems characterized by XRD, NIRS and DSC further substantiated the findings. The understanding of the fundamental physical might help scientists to predict the effects of mixing various drugs and polymers, and the effects of varying ratios.

Two-phase anaerobic digestion within a solid waste/wastewater integrated management system

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

De Gioannis, G.; Diaz, L.F.; Muntoni, A.

2008-07-01

A two-phase, wet anaerobic digestion process was tested at laboratory scale using mechanically pre-treated municipal solid waste (MSW) as the substrate. The proposed process scheme differs from others due to the integration of the MSW and wastewater treatment cycles, which makes it possible to avoid the recirculation of process effluent. The results obtained show that the supplying of facultative biomass, drawn from the wastewater aeration tank, to the solid waste acidogenic reactor allows an improvement of the performance of the first phase of the process which is positively reflected on the second one. The proposed process performed successfully, adopting mesophilicmore » conditions and a relatively short hydraulic retention time in the methanogenic reactor, as well as high values of organic loading rate. Significant VS removal efficiency and biogas production were achieved. Moreover, the methanogenic reactor quickly reached optimal conditions for a stable methanogenic phase. Studies conducted elsewhere also confirm the feasibility of integrating the treatment of the organic fraction of MSW with that of wastewater.« less

Solid State Remote Power Controllers for high voltage DC distribution systems

NASA Technical Reports Server (NTRS)

Billings, W. W.; Sundberg, G. R.

1977-01-01

Presently, hybrid Remote Power Controllers (RPC's) are in production and prototype units are available for systems utilizing 28VDC, 120VDC, 115VAC/400 Hz and 230VAC/400 Hz. This paper describes RPC development in a new area of application: HVDC distribution systems utilizing 270/300VDC. Two RPC current ratings, 1 amp and 2 amps, were selected for development as they are adequate to control 90% of projected system loads. The various aspects and trade-offs encountered in circuit development are discussed with special focus placed on the circuits that see the duress of the high dc potentials. The comprehensive evaluation tests are summarized which confirmed the RPC compliance with the specification and with system/load compatibility requirements. In addition, present technology status and new applications are summarized.

Treatment of spent wash in anaerobic mesophilic suspended growth reactor (AMSGR).

PubMed

Banu, J Rajesh; Kaliappan, S; Rajkumar, M; Beck, Dieter

2006-01-01

Approximately 400 KL of spent wash or vinasse per annum is generated at an average COD concentration of 100,000 mg/l, by over 250 distilleries in India. There is an urgent need to develop, assess and use ecofriendly methods for the disposal of this high strength wastewater. Therefore, an attempt was made to investigate a few aspects of anaerobic digestion of spent wash collected from a distillery. The study was carried out in a 4 L laboratory scale anaerobic mesophilic suspended growth reactor. After the successful startup, the organic loading was increased stepwise to assess the performance of the reactor. During the study period, biogas generated was recorded and the maximum gas generated was found to be 16.9 L at an Organic Loading Rate (OLR) of 38 g COD/L. A 500% increase in the Volatile Fatty Acid (VFA) concentration (2150 mg/L) was observed, when the OLR was increased from 38 to 39 g COD/L. During the souring phase the removal of COD, Total Solids (TS) and Volatile Solids (VS) were in the order of 52%, 40% and 46% respectively. The methane content in the biogas varied from 65% to 75%.

Treatment of suspended solids and heavy metals from urban stormwater runoff by a tree box filter.

PubMed

Geronimo, F K F; Maniquiz-Redillas, M C; Tobio, J A S; Kim, L H

2014-01-01

Particulates, inorganic and toxic constituents are the most common pollutants associated with urban stormwater runoff. Heavy metals such as chromium, nickel, copper, zinc, cadmium and lead are found to be in high concentration on paved roads or parking lots due to vehicle emissions. In order to control the rapid increase of pollutant loads in stormwater runoff, the Korean Ministry of Environment proposed the utilization of low impact developments. One of these was the application of tree box filters that act as a bioretention treatment system which executes filtration and sorption processes. In this study, a tree box filter located adjacent to an impervious parking lot was developed to treat suspended solids and heavy metal concentrations from urban stormwater runoff. In total, 11 storm events were monitored from July 2010 to August 2012. The results showed that the tree box filter was highly effective in removing particulates (up to 95%) and heavy metals (at least 70%) from the urban stormwater runoff. Furthermore, the tree box filter was capable of reducing the volume runoff by 40% at a hydraulic loading rate of 1 m/day and below.

Watershed characteristics and water-quality trends and loads in 12 watersheds in Gwinnett County, Georgia

USGS Publications Warehouse

Joiner, John K.; Aulenbach, Brent T.; Landers, Mark N.

2014-01-01

The U.S. Geological Survey, in cooperation with Gwinnett County Department of Water Resources, established a Long-Term Trend Monitoring (LTTM) program in 1996. The LTTM program is a comprehensive, long-term, water-quantity and water-quality monitoring program designed to document and analyze the hydrologic and water-quality conditions of selected watersheds of Gwinnett County, Georgia. Water-quality monitoring initially began in six watersheds and was expanded to another six watersheds in 2001. As part of the LTTM program, streamflow, precipitation, water temperature, specific conductance, and turbidity were measured continuously at the 12 watershed monitoring stations for water years 2004–09. In addition, discrete water-quality samples were collected seasonally from May through October (summer) and November through April (winter), including one base-flow and three stormflow event composite samples, during the study period. Samples were analyzed for nutrients (nitrogen and phosphorus), total organic carbon, trace elements (total lead and total zinc), total dissolved solids, and total suspended sediment (total suspended solids and suspended-sediment concentrations). The sampling scheme was designed to identify variations in water quality both hydrologically and seasonally. The 12 watersheds were characterized for basin slope, population density, land use for 2009, and the percentage of impervious area from 2000 to 2009. Precipitation in water years 2004–09 was about 18 percent below average, and the county experienced exceptional drought conditions and below average runoff in water years 2007 and 2008. Watershed water yields, the percentage of precipitation that results in runoff, typically are lower in low precipitation years and are higher for watersheds with the highest percentages of impervious areas. A comparison of base-flow and stormflow water-quality samples indicates that turbidity and concentrations of total ammonia plus organic nitrogen, total nitrogen, total phosphorus, total organic carbon, total lead, total zinc, total suspended solids, and suspended-sediment concentrations increased with increasing discharge at all watersheds. Specific conductance, however, decreased during stormflow at all watersheds, and total dissolved solids concentrations decreased during stormflow at a few of the watersheds. Total suspended solids and suspended-sediment concentrations typically were two orders of magnitude higher in stormflow samples, turbidities were about 1.5 orders of magnitude higher, total phosphorus and total zinc were about one order of magnitude higher, and total ammonia plus organic nitrogen, total nitrogen, total organic carbon, and total lead were about twofold higher than in base-flow samples. Seasonal patterns and long-term trends in flow-adjusted water-quality concentrations were identified for five representative constituents—total nitrogen, total phosphorus, total zinc, total dissolved solids, and total suspended solids. Seasonal patterns for all five constituents were fairly similar, with higher concentrations in the summer and lower concentrations in the winter. Significant linear long-term trends in stormflow composite concentrations were identified for 36 of the 60 constituent-watershed combinations (5 constituents multiplied by 12 watersheds) for the period of record through water year 2011. Significant trends typically were decreasing for total nitrogen, total phosphorus, total suspended solids, and total zinc and increasing for total dissolved solids. Total dissolved solids and total suspended solids trends had the largest magnitude changes per year. Stream water loads were estimated for 10 water-quality constituents. These estimates represent the cumulative effects of watershed characteristics, hydrologic processes, biogeochemical processes, climatic variability, and human influences on watershed water quality. Yields, in load per unit area, were used to compare loads from watersheds with different sizes. A load estimation approach developed for the Gwinnett County LTTM program that incorporates storm-event composited samples was used with some minor modifications. This approach employs the commonly used regression-model method. Concentrations were modeled as a function of discharge, time, season, and turbidity to improve model predictions and reduce errors in load estimates. Total suspended solids annual loads have been identified in Gwinnett County’s Watershed Protection Plan for target performance criterion. The amount of annual runoff is the primary factor in determining the amount of annual constituent loads. Below average runoff during water years 2004–09, especially during water years 2006–08, resulted in corresponding below average loads. Variations in constituent yields between watersheds appeared to be related to various watershed characteristics. Suspended sediment (total suspended solids and suspended-sediment concentrations) along with constituents transported predominately in solid phase (total phosphorus, total organic carbon, total lead, and total zinc) and total dissolved solids typically had higher yields from watersheds that had high percentages of impervious areas or high basin slope. High total nitrogen yields were also associated with watersheds with high percentages of impervious areas. Low total nitrogen, total suspended solids, total lead, and total zinc yields appear to be associated with watersheds that have a low percentage of high-density development. Total suspended solids yields were lower in drought years, water years 2007–08, from the combined effects of less runoff and the result of fewer, lower magnitude storms, which likely resulted in less surface erosion and lower stream sediment transport.

Preparation and characterization of citral-loaded solid lipid nanoparticles.

PubMed

Tian, Huaixiang; Lu, Zhuoyan; Li, Danfeng; Hu, Jing

2018-05-15

Citral-loaded solid lipid nanoparticles (citral-SLNs) were prepared via a high-pressure homogenization method, using glyceryl monostearate (GMS) as the solid lipid and a mixture of Tween 80 (T-80) and Span 80 (S-80) at a weight ratio of 1:1 as the surfactant. The microstructure and properties of the citral-SLNs were characterized by dynamic light scattering (DLS), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermal gravimetric analysis (TGA). The chemical stability of citral in the citral-SLNs was analyzed by solid-phase microextraction gas chromatography (SPME-GC). The GC results showed that 67.0% of the citral remained in the citral-SLN suspensions after 12 days, while only 8.22% remained in the control. Therefore, the encapsulation of citral in the solid lipid can enhance its stability in acidic surroundings. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characterization of the molecular distribution of drugs in glassy solid dispersions at the nano-meter scale, using differential scanning calorimetry and gravimetric water vapour sorption techniques.

PubMed

van Drooge, D J; Hinrichs, W L J; Visser, M R; Frijlink, H W

2006-03-09

The molecular distribution in fully amorphous solid dispersions consisting of poly(vinylpyrrolidone) (PVP)-diazepam and inulin-diazepam was studied. One glass transition temperature (T(g)), as determined by temperature modulated differential scanning calorimetry (TMDSC), was observed in PVP-diazepam solid dispersions prepared by fusion for all drug loads tested (10-80 wt.%). The T(g) of these solid dispersions gradually changed with composition and decreased from 177 degrees C for pure PVP to 46 degrees C for diazepam. These observations indicate that diazepam was dispersed in PVP on a molecular level. However, in PVP-diazepam solid dispersions prepared by freeze drying, two T(g)'s were observed for drug loads above 35 wt.% indicating phase separation. One T(g) indicated the presence of amorphous diazepam clusters, the other T(g) was attributed to a PVP-rich phase in which diazepam was dispersed on a molecular level. With both the value of the latter T(g) and the DeltaC(p) of the diazepam glass transition the concentrations of molecular dispersed diazepam could be calculated (27-35 wt.%). Both methods gave similar results. Water vapour sorption (DVS) experiments revealed that the PVP-matrix was hydrophobised by the incorporated diazepam. TMDSC and DVS results were used to estimate the size of diazepam clusters in freeze dried PVP-diazepam solid dispersions, which appeared to be in the nano-meter range. The inulin-diazepam solid dispersions prepared by spray freeze drying showed one T(g) for drug loads up to 35 wt.% indicating homogeneous distribution on a molecular level. However, this T(g) was independent of the drug load, which is unexpected because diazepam has a lower T(g) than inulin (46 and 155 degrees C, respectively). For higher drug loads, a T(g) of diazepam as well as a T(g) of the inulin-rich phase was observed, indicating the formation of amorphous diazepam clusters. From the DeltaC(p) of the diazepam glass transition the amount of molecularly dispersed diazepam was calculated (12-27 wt.%). In contrast to the PVP-diazepam solid dispersions, DVS-experiments revealed that inulin was not hydrophobised by diazepam. Consequently, the size of diazepam clusters could not be estimated. It was concluded that TMDSC enables characterization and quantification of the molecular distribution in amorphous solid dispersions. When the hygroscopicity of the carrier is reduced by the drug, DVS in combination with TMDSC can be used to estimate the size of amorphous drug clusters.

Ignition criterion for heterogeneous energetic materials based on hotspot size-temperature threshold

NASA Astrophysics Data System (ADS)

Barua, A.; Kim, S.; Horie, Y.; Zhou, M.

2013-02-01

A criterion for the ignition of granular explosives (GXs) and polymer-bonded explosives (PBXs) under shock and non-shock loading is developed. The formulation is based on integration of a quantification of the distributions of the sizes and locations of hotspots in loading events using a cohesive finite element method (CFEM) developed recently and the characterization by Tarver et al. [C. M. Tarver et al., "Critical conditions for impact- and shock-induced hot spots in solid explosives," J. Phys. Chem. 100, 5794-5799 (1996)] of the critical size-temperature threshold of hotspots required for chemical ignition of solid explosives. The criterion, along with the CFEM capability to quantify the thermal-mechanical behavior of GXs and PBXs, allows the critical impact velocity for ignition, time to ignition, and critical input energy at ignition to be determined as functions of material composition, microstructure, and loading conditions. The applicability of the relation between the critical input energy (E) and impact velocity of James [H. R. James, "An extension to the critical energy criterion used to predict shock initiation thresholds," Propellants, Explos., Pyrotech. 21, 8-13 (1996)] for shock loading is examined, leading to a modified interpretation, which is sensitive to microstructure and loading condition. As an application, numerical studies are undertaken to evaluate the ignition threshold of granular high melting point eXplosive, octahydro-1,3,5,7-tetranitro-1,2,3,5-tetrazocine (HMX) and HMX/Estane PBX under loading with impact velocities up to 350 ms-1 and strain rates up to 105 s-1. Results show that, for the GX, the time to criticality (tc) is strongly influenced by initial porosity, but is insensitive to grain size. Analyses also lead to a quantification of the differences between the responses of the GXs and PBXs in terms of critical impact velocity for ignition, time to ignition, and critical input energy at ignition. Since the framework permits explicit tracking of the influences of microstructure, loading, and mechanical constraints, the calculations also show the effects of stress wave reflection and confinement condition on the ignition behaviors of GXs and PBXs.

Modeling of thermo-mechanical fatigue and damage in shape memory alloy axial actuators

NASA Astrophysics Data System (ADS)

Wheeler, Robert W.; Hartl, Darren J.; Chemisky, Yves; Lagoudas, Dimitris C.

2015-04-01

The aerospace, automotive, and energy industries have seen the potential benefits of using shape memory alloys (SMAs) as solid state actuators. Thus far, however, these actuators are generally limited to non-critical components or over-designed due to a lack of understanding regarding how SMAs undergo thermomechanical or actuation fatigue and the inability to accurately predict failure in an actuator during use. The purpose of this study was to characterize the actuation fatigue response of Nickel-Titanium-Hafnium (NiTiHf) axial actuators and, in turn, use this characterization to predict failure and monitor damage in dogbone actuators undergoing various thermomechanical loading paths. Calibration data was collected from constant load, full cycle tests ranging from 200-600MPa. Subsequently, actuator lifetimes were predicted for four additional loading paths. These loading paths consisted of linearly varying load with full transformation (300-500MPa) and step loads which transition from zero stress to 300-400MPa at various martensitic volume fractions. Thermal cycling was achieved via resistive heating and convective cooling and was controlled via a state machine developed in LabVIEW. A previously developed fatigue damage model, which is formulated such that the damage accumulation rate is general in terms of its dependence on current and local stress and actuation strain states, was utilized. This form allows the model to be utilized for specimens undergoing complex loading paths. Agreement between experiments and simulations is discussed.

Increased physical stability and improved dissolution properties of itraconazole, a class II drug, by solid dispersions that combine fast- and slow-dissolving polymers.

PubMed

Six, Karel; Verreck, Geert; Peeters, Jef; Brewster, Marcus; Van Den Mooter, Guy

2004-01-01

Solid dispersions were prepared of itraconazole-Eudragit E100, itraconazole-PVPVA64, and itraconazole-Eudragit E100/PVPVA64 using a corotating twin-screw hot-stage extruder. Modulated temperature differential scanning calorimetry (MTDSC) was used to evaluate the miscibility of the extrudates, and dissolution experiments were performed in simulated gastric fluid without pepsin (SGF(sp)). Itraconazole and Eudragit E100 are miscible up to 13% w/w drug loading. From that concentration on, phase separation is observed. Pharmaceutical performance of this dispersion was satisfactory because 80% of the drug dissolved after 30 min. Extrudates of itraconazole and PVPVA64 were completely miscible but the pharmaceutical performance was low, with 45% of drug dissolved after 3 h. Combination of both polymers in different ratios, with a fixed drug loading of 40% w/w, was evaluated. MTDSC results clearly indicated a two-phase system consisting of itraconazole-Eudragit E100 and itraconazole-PVPVA64 phases. In these extrudates, no free crystalline or glassy clusters of itraconazole were observed; all itraconazole was mixed with one of both polymers. The pharmaceutical performance was tested in SGF(sp) for different polymer ratios, and Eudragit E100/PVPVA64 ratios of 50/50 and 60/40 showed significant increases in dissolution rate and level. Polymer ratios of 70/30 and 80/20, on the other hand, had a release of 85% after 30 min. Precipitation of the drug was never observed. The combination of the two polymers provides a solid dispersion with good dissolution properties and improved physical stability compared with the binary solid dispersions of itraconazole. Copyright 2004 Wiley-Liss, Inc.

Method and apparatus for controlling current in inductive loads such as large diameter coils

DOEpatents

Riveros, Carlos A.

1981-01-01

A method and apparatus for controlling electric current in loads that are essentially inductive, such that sparking and "ringing" current problems are reduced or eliminated. The circuit apparatus employs a pair of solid state switches (each of which switch may be an array of connected or parallel solid state switching devices such as transistors) and means for controlling those switches such that a power supply supplying two d.c. voltages (e.g. positive 150 volts d.c. and negative 150 volts d.c.) at low resistance may be connected across an essentially inductive load (e.g. a 6 gauge wire loop one hundred meters in diameter) alternatively and such that the first solid state switch is turned off and the second is turned on such that both are not on at the same time but the first turned on and the other on in less time than the inductive time constant (L/R) so that the load is essentially always presented with a low resistance path across its input. In this manner a steady AC current may be delivered to the load at a frequency desired. Shut-off problems are avoided by gradually shortening the period of switching to less than the time constant so that the maximum energy contained in the inductive load is reduced to approximately zero and dissipated in the inherent resistance. The invention circuit may be employed by adjusting the timing of switching to deliver a desired waveform (such as sinusoidal) to the load.

Development and evaluation of nitrendipine loaded solid lipid nanoparticles: influence of wax and glyceride lipids on plasma pharmacokinetics.

PubMed

Kumar, Venishetty Vinay; Chandrasekar, Durairaj; Ramakrishna, Sistla; Kishan, Veerabrahma; Rao, Yamsani Madhusudan; Diwan, Prakash Vamanrao

2007-04-20

Nitrendipine is an antihypertensive drug with poor oral bioavailability ranging from 10 to 20% due to the first pass metabolism. For improving the oral bioavailability of nitrendipine, nitrendipine loaded solid lipid nanoparticles have been developed using triglyceride (tripalmitin), monoglyceride (glyceryl monostearate) and wax (cetyl palmitate). Poloxamer 188 was used as surfactant. Hot homogenization of melted lipids and aqueous phase followed by ultrasonication at temperature above the melting point of lipid was used to prepare SLN dispersions. SLN were characterized for particle size, zeta potential, entrapment efficiency and crystallinity of lipid and drug. In vitro release studies were performed in phosphate buffer of pH 6.8 using Franz diffusion cell. Pharmacokinetics of nitrendipine loaded solid lipid nanoparticles after intraduodenal administration to conscious male Wistar rats was studied. Bioavailability of nitrendipine was increased three- to four-fold after intraduodenal administration compared to that of nitrendipine suspension. The obtained results are indicative of solid lipid nanoparticles as carriers for improving the bioavailability of lipophilic drugs such as nitrendipine by minimizing first pass metabolism.

Comparison of Standardized Cytomegalovirus (CMV) Viral Load Thresholds in Whole Blood and Plasma of Solid Organ and Hematopoietic Stem Cell Transplant Recipients with CMV Infection and Disease.

PubMed

Dioverti, M Veronica; Lahr, Brian D; Germer, Jeffrey J; Yao, Joseph D; Gartner, Michelle L; Razonable, Raymund R

2017-01-01

Quantification of cytomegalovirus (CMV) deoxyribonucleic acid (DNA) has important diagnostic, prognostic, and therapeutic implications in the management of transplant recipients. We aimed to assess a viral load in plasma and whole blood that distinguishes CMV disease from asymptomatic infection in a cohort of solid organ and hematopoietic stem cell transplantation. We prospectively measured and compared CMV viral load in paired plasma and whole blood samples collected from transplant recipients with CMV infection and disease. Cytomegalovirus viral loads were determined by a commercially available US Food and Drug Administration-approved quantitative assay (COBAS AmpliPrep/COBAS TaqMan CMV Test [CAP/CTM CMV]) calibrated to the first World Health Organization International Standard for CMV DNA quantification. Moderate agreement of CMV viral load was observed between plasma and whole blood, with 31% of samples having discordant findings, particularly among samples with low DNA levels. Among the subset of samples where both paired samples had quantifiable levels, we observed a systematic bias that reflected higher viral load in whole blood compared with plasma. Based on receiver operating curve analysis, an initial plasma CMV viral load threshold of 1700 IU/mL in solid organ transplant recipients (sensitivity 80%, specificity 74%) and 1350 IU/mL in allogeneic hematopoietic stem cell transplant recipients (sensitivity 87%, specificity 87%) distinguished CMV disease and asymptomatic infection. This study identifies standardized viral load thresholds that distinguish CMV disease from asymptomatic infection using CAP/CTM CMV assay. We propose these thresholds as potential triggers to be evaluated in prospective studies of preemptive therapy. Plasma was better than whole blood for measuring viral load using the CAP/CTM CMV assay.

Towards better modelling of drug-loading in solid lipid nanoparticles: Molecular dynamics, docking experiments and Gaussian Processes machine learning.

PubMed

Hathout, Rania M; Metwally, Abdelkader A

2016-11-01

This study represents one of the series applying computer-oriented processes and tools in digging for information, analysing data and finally extracting correlations and meaningful outcomes. In this context, binding energies could be used to model and predict the mass of loaded drugs in solid lipid nanoparticles after molecular docking of literature-gathered drugs using MOE® software package on molecularly simulated tripalmitin matrices using GROMACS®. Consequently, Gaussian processes as a supervised machine learning artificial intelligence technique were used to correlate the drugs' descriptors (e.g. M.W., xLogP, TPSA and fragment complexity) with their molecular docking binding energies. Lower percentage bias was obtained compared to previous studies which allows the accurate estimation of the loaded mass of any drug in the investigated solid lipid nanoparticles by just projecting its chemical structure to its main features (descriptors). Copyright © 2016 Elsevier B.V. All rights reserved.

Performance of a novel two-phase continuously fed leach bed reactor for demand-based biogas production from maize silage.

PubMed

Linke, Bernd; Rodríguez-Abalde, Ángela; Jost, Carsten; Krieg, Andreas

2015-02-01

This study investigated the potential of producing biogas on demand from maize silage using a novel two-phase continuously fed leach bed reactor (LBR) which is connected to an anaerobic filter (AF). Six different feeding patterns, each for 1week, were studied at a weekly average of a volatile solids (VS) loading rate of 4.5 g L(-1) d(-1) and a temperature of 38°C. Methane production from the LBR and AF responded directly proportional to the VS load from the different daily feeding and resulted in an increase up to 50-60% per day, compared to constant feeding each day. The feeding patterns had no impact on VS methane yield which corresponded on average to 330 L kg(-1). In spite of some daily shock loadings, carried out during the different feeding patterns study, the reactor performance was not affected. A robust and reliable biogas production from stalky biomass was demonstrated. Copyright © 2014 Elsevier Ltd. All rights reserved.

Development of a regionally consistent geospatial dataset of agricultural lands in the Upper Colorado River Basin, 2007-10

USGS Publications Warehouse

Buto, Susan G.; Gold, Brittany L.; Jones, Kimberly A.

2014-01-01

Irrigation in arid environments can alter the natural rate at which salts are dissolved and transported to streams. Irrigated agricultural lands are the major anthropogenic source of dissolved solids in the Upper Colorado River Basin (UCRB). Understanding the location, spatial distribution, and irrigation status of agricultural lands and the method used to deliver water to agricultural lands are important to help improve the understanding of agriculturally derived dissolved-solids loading to surface water in the UCRB. Irrigation status is the presence or absence of irrigation on an agricultural field during the selected growing season or seasons. Irrigation method is the system used to irrigate a field. Irrigation method can broadly be grouped into sprinkler or flood methods, although other techniques such as drip irrigation are used in the UCRB. Flood irrigation generally causes greater dissolved-solids loading to streams than sprinkler irrigation. Agricultural lands in the UCRB mapped by state agencies at varying spatial and temporal resolutions were assembled and edited to represent conditions in the UCRB between 2007 and 2010. Edits were based on examination of 1-meter resolution aerial imagery collected between 2009 and 2011. Remote sensing classification techniques were used to classify irrigation status for the June to September growing seasons between 2007 and 2010. The final dataset contains polygons representing approximately 1,759,900 acres of agricultural lands in the UCRB. Approximately 66 percent of the mapped agricultural lands were likely irrigated during the study period.

Measuring Fluctuating Pressure Levels and Vibration Response in a Jet Plume

NASA Technical Reports Server (NTRS)

Osterholt, Douglas J.; Knox, Douglas M.

2011-01-01

The characterization of loads due to solid rocket motor plume impingement allows for moreaccurate analyses of components subjected to such an environment. Typically, test verification of predicted loads due to these conditions is widely overlooked or unsuccessful. ATA Engineering, Inc., performed testing during a solid rocket motor firing to obtain acceleration and pressure responses in the hydrodynamic field surrounding the jet plume. The test environment necessitated a robust design to facilitate measurements being made in close proximity to the jet plume. This paper presents the process of designing a test fixture and an instrumentation package that could withstand the solid rocket plume environment and protect the required instrumentation.

Electro-dewatering of wastewater sludge: An investigation of the relationship between filtrate flow rate and electric current.

PubMed

Olivier, Jérémy; Conrardy, Jean-Baptiste; Mahmoud, Akrama; Vaxelaire, Jean

2015-10-01

Compared to conventional dewatering techniques, electrical assisted mechanical dewatering, also called electro-dewatering (EDW) is an alternative and an effective technology for the dewatering of sewage sludge with low energy consumption. The objectives of this study were to evaluate the dewatering performance and to determine the influence of the process parameters (e.g. applied electric current, applied voltage, and the initial amount of dry solids) on the kinetics of EDW-process for activated urban sludge. Also significant efforts have been devoted herein to provide comprehensive information about the EDW mechanisms and to understand the relationship between these operating conditions with regards to develop a qualitative and quantitative understanding model of the electro-dewatering process and then produce a robust design methodology. The results showed a very strong correlation between the applied electric current and the filtrate flow rate and consequently the electro-dewatering kinetics. A higher applied electric current leads to faster EDW kinetics and a higher final dry solids content. In contrast, the results of this work showed a significant enhancement of the dewatering kinetics by decreasing the mass of the dry solids introduced into the cell (commonly known as the sludge loading). Copyright © 2015 Elsevier Ltd. All rights reserved.

Future Antarctic bed topography and its implications for ice sheet dynamics

NASA Astrophysics Data System (ADS)

Adhikari, Surendra; Ivins, Erik; Larour, Eric; Seroussi, Helene; Morlighem, Mathieu; Nowicki, Sophie

2014-05-01

A recently improved ice loading history suggests that the Antarctic Ice Sheet (AIS) has been generally losing its mass since the last glacial maximum. In a sustained warming climate, the AIS is predicted to retreat at a greater pace primarily via melting beneath the ice shelves. We employ the glacial isostatic adjustment (GIA) capability of the Ice Sheet System Model (ISSM) to combine these past and future ice loadings and provide the new solid Earth computations for the AIS. We find that the past loading is relatively less important than future loading on the evolution of the future bed topography. Our computations predict that the West Antarctic Ice Sheet (WAIS) may uplift by a few meters and a few tens of meters at years 2100 and 2500 AD, respectively, and that the East Antarctic Ice Sheet (EAIS) is likely to remain unchanged or subside minimally except around the Amery Ice Shelf. The Amundsen Sea Sector of WAIS in particular is predicted to rise at the greatest rate; one hundred years of ice evolution in this region, for example, predicts that the coastline of Pine Island Bay approaches roughly 45 mm/yr in viscoelastic vertical motion. Of particular importance, we systematically demonstrate that the effect of a pervasive and large GIA uplift in the WAIS is associated with the flattening of reverse bed, reduction of local sea depth, and thus the extension of grounding line (GL) towards the continental shelf. Using the 3-D higher-order ice flow capability of ISSM, such a migration of GL is shown to inhibit the ice flow. This negative feedback between the ice sheet and the solid Earth may promote the stability to marine portions of the ice sheet in the future.

Characterization of low-dose doxorubicin-loaded silica-based nanocomposites

NASA Astrophysics Data System (ADS)

Prokopowicz, Magdalena

2018-01-01

In this study, we synthesized multicomponent solid films of low-dose doxorubicin (DOX)-loaded polydimethylsiloxane (PDMS)-SiO2/CaP nanocomposites via sol-gel process combined with the method of evaporation-induced self-assembly (EISA) at low temperature. Nanomechanical properties (elasticity and adhesion) of the synthesized multicomponent films were determined by using atomic force microscopy with a PeakForce™ quantitative nanomechanical mapping imaging technique. Solid state of DOX in the synthesized films was studied by using UV-vis and fluorescence spectroscopy. The release profile of different concentrations of DOX loaded (1, 3, and 5 wt%) on the multicomponent films was assessed using USP Apparatus 4 and via UV-vis end analysis. Results indicate drug-component interactions on the overall morphology of domains (size and shape), nanomechanical properties, and release behavior of the DOX-loaded nanocomposites. We observed a progressive increase in surface roughness and mean adhesive value with increasing concentration of DOX loaded (0-5 wt%). In addition, for all the different concentrations of DOX-loaded, we observed a diffusion-controlled drug release.

Preparation, characterization and pharmacokinetics of enrofloxacin-loaded solid lipid nanoparticles: influences of fatty acids.

PubMed

Xie, Shuyu; Zhu, Luyan; Dong, Zhao; Wang, Xiaofang; Wang, Yan; Li, Xihe; Zhou, WenZhong

2011-04-01

Enrofloxacin-loaded solid lipid nanoparticles (SLN) were prepared using fatty acids (tetradecanoic acid, palmitic acid, stearic acid) as lipid matrix by hot homogenization and ultrasonication method. The effect of fatty acids on the characteristics and pharmacokinetics of the SLN were investigated. The results showed that the encapsulation efficiency and loading capacity of nanoparticles varied with fatty acids in the order of stearic acid>palmitic acid>tetradecanoic acid. Furthermore, stearic acid-SLN had larger particle size, bigger polydispersity index (PDI) and higher zeta potential compared with the other two fatty acid formulated SLN. The SLN showed sustained releases in vitro and the released enrofloxacin had the same antibacterial activity as that of the native enrofloxacin. Although in vitro release exhibited similar patterns, within 24 h the releasing rates of the three formulations were significantly different (tetradecanoic acid-SLN>palmitic acid-SLN>stearic acid-SLN). Pharmacokinetic study after a single dose of intramuscular administration to mice demonstrated that tetradecanoic acid-SLN, palmitic acid-SLN, and stearic acid-SLN increased the bioavailability by 6.79, 3.56 and 2.39 folds, and extended the mean residence time (MRT) of the drug from 10.60 h to 180.36, 46.26 and 19.09 h, respectively. These results suggest that the enrofloxacin-fatty acid SLN are promising formulations for sustained release while fatty acids had significant influences on the characteristics and performances of the SLN. Copyright © 2010 Elsevier B.V. All rights reserved.

Effects of groundwater withdrawals from the Hurricane Fault zone on discharge of saline water from Pah Tempe Springs, Washington County, Utah

USGS Publications Warehouse

Gardner, Philip M.

2018-04-10

Pah Tempe Springs, located in Washington County, Utah, contribute about 95,000 tons of dissolved solids annually along a 1,500-foot gaining reach of the Virgin River. The river gains more than 10 cubic feet per second along the reach as thermal, saline springwater discharges from dozens of orifices located along the riverbed and above the river on both banks. The spring complex discharges from fractured Permian Toroweap Limestone where the river crosses the north-south trending Hurricane Fault. The Bureau of Reclamation Colorado River Basin Salinity Control Program is evaluating the feasibility of capturing and desalinizing the discharge of Pah Tempe Springs to improve downstream water quality in the Virgin River. The most viable plan, identified by the Bureau of Reclamation in early studies, is to capture spring discharge by pumping thermal groundwater from within the Hurricane Fault footwall damage zone and to treat this water prior to returning it to the river.Three multiple-day interference tests were conducted between November 2013 and November 2014, wherein thermal groundwater was pumped from fractured carbonate rock in the fault damage zone at rates of up to 7 cubic feet per second. Pumping periods for these tests lasted approximately 66, 74, and 67 hours, respectively, and the tests occurred with controlled streamflows of approximately 2.0, 3.5, and 24.5 cubic feet per second, respectively, in the Virgin River upstream from the springs reach. Specific conductance, water temperature, and discharge were monitored continuously in the river (upstream and downstream of the springs reach) at selected individual springs, and in the pumping discharge during each of the tests. Water levels were monitored in three observation wells screened in the thermal system. Periodic stream and groundwater samples were analyzed for dissolved-solids concentration and the stable isotopes of oxygen and hydrogen. Additional discrete measurements of field parameters (specific conductance, water temperature, pH, and discharge) were made at up to 26 sites along the springs reach. These data demonstrate the interaction between the saline, thermal groundwater system and the Virgin River, and provide estimates of reductions in dissolved-solids loads to the river.The interference tests show that pumping thermal groundwater from the shallow carbonate aquifer adjacent to the springs is effective at capturing high dissolved-solids loads discharging from Pah Tempe Springs before they enter the Virgin River. Discharge measurements made in the Virgin River downstream of the springs reach show that streamflow is reduced by approximately the amount pumped, indicating that complete capture of thermal discharge is possible. During the February 2014 test, the dissolved-solids load removed by pumping (190 tons per day) was approximately equal to the dissolved-solids load reduction observed in the river below the springs reach, indicating near 100-percent efficient capture of spring-sourced dissolved solids. However, an observed decrease in temperature and specific conductance of the pumping discharge during the high-flow test in November 2014 showed that capture of the cool, fresh river water can occur and is more likely at a higher stage in the Virgin River.

Vertical load capacities of roof truss cross members.

PubMed

Gearhart, David F; Morsy, Mohamed Khaled

2016-05-01

Trusses used for roof support in coal mines are constructed of two grouted bolts installed at opposing forty-five degree angles into the roof and a cross member that ties the angled bolts together. The load on the cross member is vertical, which is transverse to the longitudinal axis, and therefore the cross member is loaded in the weakest direction. Laboratory tests were conducted to determine the vertical load capacity and deflection of three different types of cross members. Single-point load tests, with the load applied in the center of the specimen and double-point load tests, with a span of 2.4 m, were conducted. For the single-point load configuration, the yield of the 25 mm solid bar cross member was nominally 98 kN of vertical load, achieved at 42 cm of deflection. For cable cross members, yield was not achieved even after 45 cm of deflection. Peak vertical loads were about 89 kN for 17 mm cables and 67 kN for the 15 mm cables. For the double-point load configurations, the 25 mm solid bar cross members yielded at 150 kN of vertical load and 25 cm of deflection. At 25 cm of deflection individual cable strands started breaking at 133 and 111 kN of vertical load for the 17 and 15 mm cable cross members respectively.

Synergistic role of solid lipid and porous silica in improving the oral delivery of weakly basic poorly water soluble drugs.

PubMed

Yasmin, Rokhsana; Rao, Shasha; Bremmell, Kristen; Prestidge, Clive

2017-01-01

Oral absorption of weakly basic drugs (e.g. cinnarizine (CIN)) is limited by their pH dependent precipitation in intestinal conditions. To overcome this challenge, a novel drug delivery system composed of solid lipid and porous silica, namely silica encapsulated solid lipid (SESL) particles, was developed via hot homogenization of melted lipid dispersion, followed by ultra-sonication of the silica stabilized homogenized melted lipid dispersion. Scanning electron microscope (SEM) images of the SESL formulation revealed non-spherical and aggregated hybrid particles, with rough exterior and structured nanoparticles visible on the surface. A 1.5, 2.2 and 7-fold improvement in the dissolution of CIN was observed for the SESL particles, under simulated intestinal non-digesting conditions, in comparison to the drug loaded in solid lipid (CIN-SL) matrix, drug loaded in porous silica (CIN-PS) and pure drug powder. Under simulated intestinal digestive condition, significant improvement in the drug solubilization was reported for the SESL formulation in compared to the individual drug loaded systems i.e. CIN-PS and CIN-SL. Thereby, silica encapsulated solid lipid system provides a promising oral delivery approach for poorly water soluble weakly basic drugs. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of agitation on methanogenesis stage of two-stage anaerobic digestion of palm oil mill effluent (POME) into biogas

NASA Astrophysics Data System (ADS)

Trisakti, Bambang; Irvan, Zahara, Intan; Taslim, Turmuzi, Muhammad

2017-05-01

This study is an assessment of the effect of agitation on biogas production on methanogenesis stage. Methanogenesis is the second stage of two-stage anaerobic digestion of palm oil effluent (POME) into biogas. The purpose of this study is to get the effect of agitation on growth of microorganisms, degradation of organic substances, and biogas production and composition. Initially, the suitable loading up was determined by varying the HRT at 100, 40, 6, and 4 days in the continuous stirred tank reactor (CSTR) with agitation rate 100 rpm, pH 6.7-7.5, at room temperature. Next, effect of agitation on the process was determined by varying agitation rate at 50, 100, 150, and 200 rpm. The substrate used was the effluent of the acidogenesis stage that fed to the CSTR four times a day. Analysis of total solids (TS), volatile solids (VS), total suspended solids (TSS), volatile suspended solids (VSS), and chemical oxygen demand (COD) were conducted in order to study the growth of microorganisms and their abilities in converting organic compound to produce biogas. Production and composition of biogas were also determined by measuring the volume of biogas and content of H2S and CO2. The result showed that the pH and alkalinity it was still within the range of methanogenesis process. The growth of microorganisms were increased with the increasing of agitation rate. However, the best degradation of organic substances, biogas production, and biogas composition were achieved at 100 rpm. The VS decomposition, COD removal, biogas production, CO2 content, and CH4 content at 100 rpm were 67.44 ± 3.59%, 81.00%, 58.87 ± 6.27 L/kg-ΔVS, 23.36%, and 76.64%, respectively.

An all-solid-state microsecond-range quasi-square pulse generator based on fractional-turn ratio saturable pulse transformer and anti-resonance network.

PubMed

Chen, Rong; Yang, Jianhua; Cheng, Xinbing; Pan, Zilong

2017-03-01

High voltage pulse generators are widely applied in a number of fields. Defense and industrial applications stimulated intense interests in the area of pulsed power technology towards the system with high power, high repetition rate, solid state characteristics, and compact structure. An all-solid-state microsecond-range quasi-square pulse generator based on a fractional-turn ratio saturable pulse transformer and anti-resonance network is proposed in this paper. This generator consists of a charging system, a step-up system, and a modulating system. In this generator, the fractional-turn ratio saturable pulse transformer is the key component since it acts as a step-up transformer and a main switch during the working process. Demonstrative experiments show that if the primary storage capacitors are charged to 400 V, a quasi-square pulse with amplitude of about 29 kV can be achieved on a 3500 Ω resistive load, as well as the pulse duration (full width at half maximum) of about 1.3 μs. Preliminary repetition rate experiments are also carried out, which indicate that this pulse generator could work stably with the repetition rates of 30 Hz and 50 Hz. It can be concluded that this kind of all-solid-state microsecond-range quasi-square pulse generator can not only lower both the operating voltage of the primary windings and the saturable inductance of the secondary windings, thus ideally realizing the magnetic switch function of the fractional-turn ratio saturable pulse transformer, but also achieve a quasi-square pulse with high quality and fixed flat top after the modulation of a two-section anti-resonance network. This generator can be applied in areas of large power microwave sources, sterilization, disinfection, and wastewater treatment.

Solid lipid nanoparticles loading adefovir dipivoxil for antiviral therapy

PubMed Central

Zhang, Xing-guo; Miao, Jing; Li, Min-wei; Jiang, Sai-ping; Hu, Fu-qiang; Du, Yong-zhong

2008-01-01

Herein, solid lipid nanoparticles (SLN) were proposed as a new drug delivery system for adefovir dipivoxil (ADV). The octadecylamine-fluorescein isothiocynate (ODA-FITC) was synthesized and used as a fluorescence maker to be incorporated into SLN to investigate the time-dependent cellular uptake of SLN by HepG2.2.15. The SLN of monostearin with ODA-FITC or ADV were prepared by solvent diffusion method in an aqueous system. About 15 wt% drug entrapment efficiency (EE) and 3 wt% drug loading (DL) could be reached in SLN loading ADV. Comparing with free ADV, the inhibitory effects of ADV loaded in SLN on hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg) and hepatitis B virus (HBV) DNA levels in vitro were significantly enhanced. PMID:18543406

Kinetic modelling of anaerobic hydrolysis of solid wastes, including disintegration processes

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

García-Gen, Santiago; Sousbie, Philippe; Rangaraj, Ganesh

2015-01-15

Highlights: • Fractionation of solid wastes into readily and slowly biodegradable fractions. • Kinetic coefficients estimation from mono-digestion batch assays. • Validation of kinetic coefficients with a co-digestion continuous experiment. • Simulation of batch and continuous experiments with an ADM1-based model. - Abstract: A methodology to estimate disintegration and hydrolysis kinetic parameters of solid wastes and validate an ADM1-based anaerobic co-digestion model is presented. Kinetic parameters of the model were calibrated from batch reactor experiments treating individually fruit and vegetable wastes (among other residues) following a new protocol for batch tests. In addition, decoupled disintegration kinetics for readily and slowlymore » biodegradable fractions of solid wastes was considered. Calibrated parameters from batch assays of individual substrates were used to validate the model for a semi-continuous co-digestion operation treating simultaneously 5 fruit and vegetable wastes. The semi-continuous experiment was carried out in a lab-scale CSTR reactor for 15 weeks at organic loading rate ranging between 2.0 and 4.7 g VS/L d. The model (built in Matlab/Simulink) fit to a large extent the experimental results in both batch and semi-continuous mode and served as a powerful tool to simulate the digestion or co-digestion of solid wastes.« less

Strategies for the anaerobic digestion of the organic fraction of municipal solid waste: an overview.

PubMed

Hartmann, H; Ahring, B K

2006-01-01

Different process strategies for anaerobic digestion of the organic fraction of municipal solid waste (OFMSW) are reviewed weighing high-solids versus low-solids, mesophilic versus thermophilic and single-stage versus multi-stage processes. The influence of different waste characteristics such as composition of biodegradable fractions, C:N ratio and particle size is described. Generally, source sorting of OFMSW and a high content of food waste leads to higher biogas yields than the use of mechanically sorted OFMSW. Thermophilic processes are more efficient than mesophilic processes in terms of higher biogas yields at different organic loading rates (OLR). Highest biogas yields are achieved by means of wet thermophilic processes at OLRs lower than 6 kg-VS x m(-3) d(-1). High-solids processes appear to be relatively more efficient when OLRs higher than 6 kg-VS x m(-3)d(-1) are applied. Multi-stage systems show in some investigations a higher reduction of recalcitrant organic matter compared to single-stage systems, but they are seldom applied in full-scale. An extended cost-benefit calculation shows that the highest overall benefit of the process is achieved at an OLR that is lower and a hydraulic retention time (HRT) that is longer than those values of OLR and HRT, at which the highest biogas production is achieved.

49 CFR 177.838 - Class 4 (flammable solid) materials, Class 5 (oxidizing) materials, and Division 4.2 (pyroforic...

Code of Federal Regulations, 2014 CFR

2014-10-01

... (flammable solid) or Class 5 (oxidizing) materials shall be contained entirely within the body of the motor.... Special care shall also be taken in the loading of any motor vehicle with Class 4 (flammable solid) or... 49 Transportation 2 2014-10-01 2014-10-01 false Class 4 (flammable solid) materials, Class 5...

49 CFR 177.838 - Class 4 (flammable solid) materials, Class 5 (oxidizing) materials, and Division 4.2 (pyroforic...

Code of Federal Regulations, 2013 CFR

2013-10-01

... (flammable solid) or Class 5 (oxidizing) materials shall be contained entirely within the body of the motor.... Special care shall also be taken in the loading of any motor vehicle with Class 4 (flammable solid) or... 49 Transportation 2 2013-10-01 2013-10-01 false Class 4 (flammable solid) materials, Class 5...

49 CFR 177.838 - Class 4 (flammable solid) materials, Class 5 (oxidizing) materials, and Division 4.2 (pyroforic...

Code of Federal Regulations, 2012 CFR

2012-10-01

... (flammable solid) or Class 5 (oxidizing) materials shall be contained entirely within the body of the motor.... Special care shall also be taken in the loading of any motor vehicle with Class 4 (flammable solid) or... 49 Transportation 2 2012-10-01 2012-10-01 false Class 4 (flammable solid) materials, Class 5...

The impact of nanoparticles on aerobic degradation of municipal solid waste.

PubMed

Yazici Guvenc, Senem; Alan, Burcu; Adar, Elanur; Bilgili, Mehmet Sinan

2017-04-01

The amount of nanoparticles released from industrial and consumer products has increased rapidly in the last decade. These products may enter landfills directly or indirectly after the end of their useful life. In order to determine the impact of TiO 2 and Ag nanoparticles on aerobic landfilling processes, municipal solid waste was loaded to three pilot-scale aerobic landfill bioreactors (80 cm diameter and 350 cm height) and exposed to TiO 2 (AT) and Ag (AA) nanoparticles at total concentrations of 100 mg kg -1 of solid waste. Aerobic landfill bioreactors were operated under the conditions about 0.03 L min -1 kg -1 aeration rate for 250 days, during which the leachate, solid waste, and gas characteristics were measured. The results indicate that there was no significant difference in the leachate characteristics, gas constituents, solid quality parameters, and temperature variations, which are the most important indicators of landfill operations, and overall aerobic degradation performance between the reactors containing TiO 2 and Ag nanoparticles, and control (AC) reactor. The data also indicate that the pH levels, ionic strength, and the complex formation capacity of nanoparticles with Cl - ions can reduce the toxicity effects of nanoparticles on aerobic degradation processes. The results suggest that TiO 2 and Ag nanoparticles at concentrations of 100 mg kg -1 of solid waste do not have significant impacts on aerobic biological processes and waste management systems.

Idebenone-loaded solid lipid nanoparticles for drug delivery to the skin: in vitro evaluation.

PubMed

Montenegro, Lucia; Sinico, Chiara; Castangia, Ines; Carbone, Claudia; Puglisi, Giovanni

2012-09-15

Idebenone (IDE), a synthetic derivative of ubiquinone, shows a potent antioxidant activity that could be beneficial in the treatment of skin oxidative damages. In this work, the feasibility of targeting IDE into the upper layers of the skin by topical application of IDE-loaded solid lipid nanoparticles (SLN) was evaluated. SLN loading different amounts of IDE were prepared by the phase inversion temperature method using cetyl palmitate as solid lipid and three different non-ionic surfactants: ceteth-20, isoceteth-20 and oleth-20. All IDE loaded SLN showed a mean particle size in the range of 30-49 nm and a single peak in size distribution. In vitro permeation/penetration experiments were performed on pig skin using Franz-type diffusion cells. IDE penetration into the different skin layers depended on the type of SLN used while no IDE permeation occurred from all the SLN under investigation. The highest IDE content was found in the epidermis when SLN contained ceteth-20 or isoceteth-20 as surfactant while IDE distribution into the upper skin layers depended on the amount of IDE loaded when oleth-20 was used as surfactant. These results suggest that the SLN tested could be an interesting carrier for IDE targeting to the upper skin layers. Copyright © 2012 Elsevier B.V. All rights reserved.

Effects of feedstock ratio and organic loading rate on the anaerobic mesophilic co-digestion of rice straw and cow manure.

PubMed

Li, Dong; Liu, Shengchu; Mi, Li; Li, Zhidong; Yuan, Yuexiang; Yan, Zhiying; Liu, Xiaofeng

2015-01-01

In order to investigate the effects of feedstock ratio and organic loading rate (OLR) on the anaerobic mesophilic co-digestion of rice straw (RS) and cow manure (CM), batch tests (2.5L) were carried out at volatile solid (VS) ratios of 0:1, 1:2, 1:1, 2:1, and 1:0 (RS/CM), and continuous bench experiments (40 L) were carried out at OLRs of 3.0, 3.6, 4.2, 4.8, 6.0, 8.0, and 12.0 kg VS/(m(3) d) with optimal VS ratio. The optimal VS ratio was found to be 1:1. Stable and efficient co-digestion with average specific biogas production of 383.5L/kg VS and volumetric biogas production rate of 2.30 m(3)/(m(3) d) was obtained at an OLR of 6 kg VS/(m(3) d). Anaerobic co-digestion was severely inhibited by the accumulation of volatile fatty acids instead of ammonia when the OLR was 12 kg VS/(m(3) d). Further, significant foaming was observed at OLR ⩾ 8 kg VS/(m(3) d). Copyright © 2015 Elsevier Ltd. All rights reserved.

An experimental model of COD abatement in MBBR based on biofilm growth dynamic and on substrates' removal kinetics.

PubMed

Siciliano, Alessio; De Rosa, Salvatore

2016-08-01

In this study, the performance of a lab-scale Moving Bed Biofilm Reactor (MBBR) under different operating conditions was analysed. Moreover, the dependence of the reaction rates both from the concentration and biodegradability of substrates and from the biofilm surface density, by means of several batch kinetic tests, was investigated. The reactor controls exhibited an increasing COD (Chemical Oxygen Demand) removal, reaching maximum yields (close to 90%) for influent loadings of up to12.5 gCOD/m(2)d. From this value, the pilot plant performance decreased to yields of only about 55% for influent loadings greater than 16 gCOD/m(2)d. In response to the influent loading increase, the biofilm surface density exhibited a logistic growing trend until reaching a maximum amount of total attached solids of about 9.5 g/m(2). The kinetic test results indicated that the COD removal rates for rapidly biodegradable, rapidly hydrolysable and slowly biodegradable substrates were not affected by the organic matter concentrations. Instead, first-order kinetics were detected with respect to biofilm surface density. The experimental results permitted the formulation of a mathematical model to predict the MBBR organic matter removal efficiency. The validity of the model was successfully tested in the lab-scale plant.

Energy density and rate limitations in structural composite supercapacitors

NASA Astrophysics Data System (ADS)

Snyder, J. F.; Gienger, E.; Wetzel, E. D.; Xu, K.

2012-06-01

The weight and volume of conventional energy storage technologies greatly limits their performance in mobile platforms. Traditional research efforts target improvements in energy density to reduce device size and mass. Enabling a device to perform additional functions, such as bearing mechanical load, is an alternative approach as long as the total mass efficiency exceeds that of the individual materials it replaces. Our research focuses on structural composites that function as batteries and supercapacitors. These multifunctional devices could be used to replace conventional structural components, such as vehicle frame elements, to provide significant system-level weight reductions and extend mission times. Our approach is to design structural properties directly into the electrolyte and electrode materials. Solid polymer electrolyte materials bind the system and transfer load to the fibers while conducting ions between the electrodes. Carbon fiber electrodes provide a route towards optimizing both energy storage and load-bearing capabilities, and may also obviate the need for a separate current collector. The components are being integrated using scalable, cost-effective composite processing techniques that are amenable to complex part shapes. Practical considerations of energy density and rate behavior are described here as they relate to materials used. Our results highlight the viability as well as the challenges of this multifunctional approach towards energy storage.

A crystal plasticity model incorporating the effects of precipitates in superalloys: Application to tensile, compressive, and cyclic deformation of Inconel 718

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

Ghorbanpour, Saeede; Zecevic, Milovan; Kumar, Anil

An elasto-plastic polycrystal plasticity model is developed and applied to an Inconel 718 (IN718) superalloy that was produced by additive manufacturing (AM). The model takes into account the contributions of solid solution, precipitates shearing, and grain size and shape effects into the initial slip resistance. Non-Schmid effects and backstress are also included in the crystal plasticity model for activating slip. The hardening law for the critical resolved shear stress is based on the evolution of dislocation density. In using the same set of material and physical parameters, the model is compared against a suite of compression, tension, and large-strain cyclicmore » mechanical test data applied in different AM build directions. We demonstrate that the model is capable of predicting the particularities of both monotonic and cyclic deformation to large strains of the alloy, including decreasing hardening rate during monotonic loading, the non-linear unloading upon the load reversal, the Bauschinger effect, the hardening rate change during loading in the reverse direction as well as plastic anisotropy and the concomitant microstructure evolution. It is anticipated that the general model developed here can be applied to other multiphase alloys containing precipitates.« less

A crystal plasticity model incorporating the effects of precipitates in superalloys: Application to tensile, compressive, and cyclic deformation of Inconel 718

DOE PAGES

Ghorbanpour, Saeede; Zecevic, Milovan; Kumar, Anil; ...

2017-09-14

An elasto-plastic polycrystal plasticity model is developed and applied to an Inconel 718 (IN718) superalloy that was produced by additive manufacturing (AM). The model takes into account the contributions of solid solution, precipitates shearing, and grain size and shape effects into the initial slip resistance. Non-Schmid effects and backstress are also included in the crystal plasticity model for activating slip. The hardening law for the critical resolved shear stress is based on the evolution of dislocation density. In using the same set of material and physical parameters, the model is compared against a suite of compression, tension, and large-strain cyclicmore » mechanical test data applied in different AM build directions. We demonstrate that the model is capable of predicting the particularities of both monotonic and cyclic deformation to large strains of the alloy, including decreasing hardening rate during monotonic loading, the non-linear unloading upon the load reversal, the Bauschinger effect, the hardening rate change during loading in the reverse direction as well as plastic anisotropy and the concomitant microstructure evolution. It is anticipated that the general model developed here can be applied to other multiphase alloys containing precipitates.« less

Continuous anaerobic digestion of food waste and design of digester with lipid removal.

PubMed

Li, Dong; Sun, Yongming; Guo, Yanfeng; Yuan, Zhenhong; Wang, Yao; Zhen, Feng

2013-01-01

Separation of municipal solid waste has been implemented in many cities in China. As a major component of municipal solid waste, food waste can be treated by anaerobic digestion (AD) for energy production. To provide reference data for disposing of food waste through engineering applications, continuous AD was carried out under various organic loading rates (OLRs) at 27 +/- 2 degrees C in the laboratory. The anaerobic reactor was stable with pH 7.0-7.1, total volatile fatty acid (VFA) concentrations of 206-746 mg/L, and NH4+ -N concentrations of 525-1293 mg/L when the OLR was 1.118-5.588 kg volatile solids (VS)/m(3) x d. The maximum volumetric biogas production rate was 4.41 L/L x d when the OLR was increased to 5.588 kg VS/m(3) x d with a hydraulic retention time of 30 d. When the OLR was increased to 6.706 and 8.382 kg VS/m(3) x d, biogas production was seriously inhibited by VFAs, with maximum total VFA and propionate concentrations of 8738 mg/L and 2864 mg/L, respectively. Due to the incomplete degradation of lipids, the specific methane production rate of 353-488 L/kg VS accounted for 55.2-76.3% of the theoretical methane potential calculated based on the component composition. A retrofitted anaerobic digester with lipid removal was designed to improve the efficiency.

Are nanostructured lipid carriers (NLCs) better than solid lipid nanoparticles (SLNs): development, characterizations and comparative evaluations of clotrimazole-loaded SLNs and NLCs?

PubMed

Das, Surajit; Ng, Wai Kiong; Tan, Reginald B H

2012-08-30

In recent years, solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) are among the popular research topics for the delivery of lipophilic drugs. Although SLNs have demonstrated several beneficial properties as drug-carrier, limited drug-loading and expulsion of drug during storage led to the development of NLCs. However, the superiority of NLCs over SLNs has not been fully established yet due to the contradictory results. In this study, SLNs and NLCs were developed using clotrimazole as model drug. Size, polydispersity index (PI), zeta potential (ZP), drug-loading (L), drug encapsulation efficiency (EE), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffractometry (XRD), drug release and stability of SLNs and NLCs were compared. Critical process parameters exhibited significant impact on the nanoparticles' properties. Size, PI, ZP and EE of the developed SLNs and NLCs were<100 nm, <0.17, <-22 mV and>82%, respectively. SEM images of SLNs and NLCs revealed spherical shaped particles (≈ 100 nm). DSC and XRD studies indicated slight difference between SLNs and NLCs as well as disappearance of the crystalline peak(s) of the encapsulated drug. NLCs demonstrated faster drug release than SLNs at low drug-loading, whereas there was no significant difference in drug release from SLNs and NLCs at high drug-loading. However, sustained/prolonged drug release was observed from both formulations. Furthermore, this study suggests that the drug release experiment should be designed considering the final application (topical/oral/parenteral) of the product. Regarding stability, NLCs showed better stability (in terms of size, PI, EE and L) than SLNs at 25°C. Moreover, there was no significant difference in drug release profile of NLCs after 3 months storage in compare to fresh NLCs, while significant change in drug release rate was observed in case of SLNs. Therefore, NLCs have an edge over SLNs. Copyright © 2012 Elsevier B.V. All rights reserved.

Thermophilic biogasification of biomass

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

Ghosh, S.; Klass, D.L.; Edwards, V.H.

1980-01-01

Secondary sewage effluent- and fresh-water-grown water hyacinths (Eichhornia crassipes), Coastal Bermuda grass (Cynodon dactylon), and a hyacinth-grass-municipal solid waste-sludge (biomass-waste) blend were used as test feeds to develop a fast thermophilic biomass- digestion process. For the pure biomass feeds thermophilic digestion has no apparent advantage over mesophilic digestion, but the reverse is true for the biomass-waste blend. Alkaline pretreatment of the feed improved thermophilic digester performance substantially. For a given plant feed load, the reactor volume, culture-heating requirements, and CH4 production rate for thermophilic digestion of the pretreated biomass-waste feed were 18,46, and 135% of those for conventional mesophilic digestion.more » For a biomass-waste feed the respective volatile solids reduction and energy recovery efficiencies were 46 and 49% for thermophilic and 36 and 43% for mesophilic digestions.« less

A sustainable solid state recycling of pure aluminum by means of friction stir extrusion process (FSE)

NASA Astrophysics Data System (ADS)

Mehtedi, Mohamad El; Forcellese, Archimede; Simoncini, Michela; Spigarelli, Stefano

2018-05-01

In this research, the feasibility of solid-state recycling of pure aluminum AA1099 machining chips using FSE process is investigated. In the early stage, a FE simulation was conducted in order to optimize the die design and the process parameters in terms of plunge rotational speed and extrusion rate. The AA1099 aluminum chips were produced by turning of an as-received bar without lubrication. The chips were compacted on a MTS machine up to 150KN of load. The extruded samples were analyzed by optical and electron microscope in order to see the material flow and to characterize the microstructure. Finally, micro-hardness Vickers profiles were carried out, in both longitudinal and transversal direction of the obtained profiles, in order to investigate the homogeneity of the mechanical properties of the extrudate.

Settling and survival profile of enteric pathogens in the swine effluent for water reuse purpose.

PubMed

Fongaro, G; Kunz, A; Magri, M E; Schissi, C D; Viancelli, A; Philippi, L S; Barardi, C R M

2016-11-01

The present study evaluated the pathogens persistence and settling profile in swine effluent. We determined the enteric pathogens settling characteristics, their survival and inactivation profile in swine effluent (for water reuse purpose) and in sludge (generated after aerobic treatment - during secondary settling process). The study was performed in laboratorial-scale and in full-scale (manure treatment plant). Enteric viruses and enteric bacteria were used as biomarkers. Results showed that these enteric pathogens were significantly reduced from swine effluent during secondary settling process, and enteric viruses removal was correlated with the suspended solids decantation. The design of secondary settlers can be adapted to improve pathogens removal, by diminishing the solids loading rate per area and time, ending in higher hydraulic retention times. Copyright © 2016 Elsevier GmbH. All rights reserved.

Supercritical fluid precipitation of ketoprofen in novel structured lipid carriers for enhanced mucosal delivery--a comparison with solid lipid particles.

PubMed

Gonçalves, V S S; Matias, A A; Rodríguez-Rojo, S; Nogueira, I D; Duarte, C M M

2015-11-10

Structured lipid carriers based on mixture of solid lipids with liquid lipids are the second generation of solid lipid particles, offering the advantage of improved drug loading capacity and higher storage stability. In this study, structured lipid carriers were successfully prepared for the first time by precipitation from gas saturated solutions. Glyceryl monooleate (GMO), a liquid glycerolipid, was selected in this work to be incorporated into three solid glycerolipids with hydrophilic-lipophilic balance (HLB) ranging from 1 to 13, namely Gelucire 43/01™, Geleol™ and Gelucire 50/13™. In general, microparticles with a irregular porous morphology and a wide particle size distribution were obtained. The HLB of the individual glycerolipids might be a relevant parameter to take into account during the processing of solid:liquid lipid blends. As expected, the addition of a liquid lipid into a solid lipid matrix led to increased stability of the lipid carriers, with no significant modifications in their melting enthalpy after 6 months of storage. Additionally, Gelucire 43/01™:GMO particles were produced with different mass ratios and loaded with ketoprofen. The drug loading capacity of the structured lipid carriers increased as the GMO content in the particles increased, achieving a maximum encapsulation efficiency of 97% for the 3:1 mass ratio. Moreover, structured lipid carriers presented an immediate release of ketoprofen from its matrix with higher permeation through a mucous-membrane model, while solid lipid particles present a controlled release of the drug with less permeation capacity. Copyright © 2015. Published by Elsevier B.V.

Characterization of domestic graywater and graywater solids.

PubMed

Sievers, Jan Christian; Londong, Jörg

2018-03-01

The knowledge of loads and concentrations is fundamental for the design of graywater treatment units, but the data on the characteristics of graywater and in particular graywater solids are weak. As general design values regarding graywater treatment facilities are not available for Germany, the objective of this article is to elaborate the characteristics of graywater and graywater solids. This paper describes the results of six sampling campaigns carried out on graywater systems in the German cities Berlin, Lübeck and Kiel. All graywater samples were collected proportional to the flow and the graywater solids were gathered separately. The collected data include graywater volumes and characteristics regarding the organic pollution (chemical oxygen demand (COD), 5-day biochemical oxygen demand (BOD 5 )) and nutrients (total nitrogen (TN), total phosphorus (TP)). The graywater volume fluctuated depending on the location. The specific average flow was 68 litre per inhabitant per day (L/inh.d). Inhabitant-specific loads of 49.3 gCOD t /inh·d, 28 gBOD 5 /inh.d, 1 gTN t /inh.d and 0.38 gTP t /inh.d (subscript 't' = total) were found. Information about the composition of graywater solids in terms of quantity and quality is seriously lacking. Therefore, graywater solids were examined with respect to organic matter (COD) and nutrients (TN, TP). The contribution of graywater solids with particle sizes over 200 microns in relation to the total inhabitant-specific load was approximately 3-8% depending on the parameter. The qualitative and quantitative characteristics of the investigated graywater fractions may serve as a base for the estimation of design values.

Design and in vivo evaluation of solid lipid nanoparticulate systems of Olanzapine for acute phase schizophrenia treatment: Investigations on antipsychotic potential and adverse effects.

PubMed

Joseph, Emil; Reddi, Satish; Rinwa, Vibhu; Balwani, Garima; Saha, Ranendra

2017-06-15

The present paper discusses the design, characterization and in vivo evaluation of glyceryl monostearate nanoparticles of Olanzapine, an atypical antipsychotic drug for acute schizophrenia treatment, during which hospitalization is mandatory and adverse effects are at its peak. The solid lipid nanoparticulate system was obtained by emulsification-ultra sonication technique wherein three factors such as solid lipid content, concentration of surfactant and drug: solid lipid ratio were selected at three different levels in order to study their influence on significant characteristic responses such as particle size, encapsulation efficiency and drug content. A Box Behnken design with 17 runs involving whole factors at three levels was employed for the study. The optimized formulation was further coated with Polysorbate 80 in order to enhance its brain targeting potential through endocytosis transport process via blood brain barrier. The designed formulations were pre-clinically tested successfully in Wistar rat model for in vivo antipsychotic efficacy (apomorphine induced psychosis) and adverse effects (weight gain study for 28days). The results obtained indicated that solid lipid nanoparticles had very narrow size distribution (151.29±3.36nm) with very high encapsulation efficiency (74.51±1.75%). Morphological studies by SEM have shown that solid lipid nanoparticles were spherical in shape with smooth surface. Olanzapine-loaded nanoparticles prepared from solid lipid, extended the release of drug for 48h, as found by the in vitro release studies. The formulations also exhibited high redispersibility after freeze-drying and stability study results demonstrated good stability, with no significant change for a period of 6months. In vivo evaluation and adverse effects studies of Olanzapine-loaded nanoparticulate systems in animal model have demonstrated an improved therapeutic efficacy than pure Olanzapine. The antipsychotic effect of drug loaded nanoparticulate systems was maintained for 48h as compared to 8h antipsychotic action of pure Olanzapine solution. The weight gain studies for 28days demonstrated a significant inhibition in weight gain for Olanzapine-loaded nanoparticulate systems as compared to the pure Olanzapine. The present research findings indicate that OLN-loaded nanoparticulate systems may be highly promising for effective delivery of Olanzapine with better efficacy and minimum adverse effects. Copyright © 2017 Elsevier B.V. All rights reserved.

Preparation and physicochemical characteristics of polylactide microspheres of emamectin benzoate by modified solvent evaporation/extraction method.

PubMed

Zhang, Shao Fei; Chen, Peng Hao; Zhang, Fei; Yang, Yan Fang; Liu, De Kun; Wu, Gang

2013-12-18

Emamectin benzoate is highly effective against insect pests and widely used in the world. However, its biological activity is limited because of high resistance of target insects and rapid degradation speed in fields. Preparation and physicochemical characterization of degradable microcapsules of emamectin benzoate were studied by modified solvent evaporation/extraction method using polylactide (PLA) as wall material. The influence of different compositions of the solvent in internal organic phase and external aqueous phase on diameter, span, pesticide loading, and entrapment rate of the microspheres was investigated. The results indicated that the process of solvent extraction and the formation of the microcapsules would be accelerated by adding water-miscible organic solvents such as ethyl ether, acetone, ethyl acetate, or n-butanol into internal organic phase and external aqueous phase. Accelerated formation of the microcapsules would result in entrapment rates of emamectin benzoate increased to as high as 97%. In addition, by adding ethanol into the external aqueous phase, diameters would reduce to 6.28 μm, whereas the loading efficiency of emamectin benzoate did not increase. The PLA microspheres prepared under optimum conditions were smoother and more spherical. The degradation rate in PLA microspheres of emamectin benzoate on the 10th day was 4.29 ± 0.74%, whereas the degradation rates of emamectin benzoate in methanol solution and solid technical material were 46.3 ± 2.11 and 22.7 ± 1.51%, respectively. The PLA skeleton had combined with emamectin benzoate in an amorphous or molecular state by using differential scanning calorimetry (DSC) determination. The results indicated that PLA microspheres of emamectin benzoate with high entrapment rate, loading efficiency, and physicochemical characteristics could be obtained by adding water-miscible organic solvents into the internal organic phase and external aqueous phase.

Sediment transport and water-quality characteristics and loads, White River, northwestern Colorado, water years 1975-88

USGS Publications Warehouse

Tobin, R.L.

1993-01-01

Streamflow, sediment, and water-quality data are summarized for 6 sites on the White River, Colorado for water years 1975-88. Correlation techniques were used to estimate annual data for unmeasured years. Annual stream discharge in the main stem of the White River ranged from about 200,000 to about 1 million acre-feet. Generally, bedload was less than/= 3.3 percent of total sediment load. Annual suspended-sediment loads ranged from about 2,100 tons at the upstream sites on the North Fork and South Fork of the White River to about 2 million tons at the most downstream site. Average annual suspended-sediment loads ranged from about 11,000 tons at the upstream sites to about 705,000 tons at the most downstream site. Annual capacity losses in a 50,000 acre-ft reservoir could range from less than 0.01 percent near upstream sites to about 2.5 percent near downstream sites. Maximum water temperatures in the White River ranged from less than 20 to 25 C in summer. Specific conductance ranged from 200 to 1,000 microsiemens/cm. Generally, values of pH ranged from 7.6 to 8.8, and concentrations of dissolved oxygen were greater than 6.0 mg/L. In small streamflows, values of pH and dissolved oxygen were affected by biologic processes. Composition of dissolved solids in the White River was mostly calcium, bicarbonate, and(or) sulfate. Changes in the composition of dissolved solids caused by the changes in the concentrations of sodium and sulfate were greatest in small stream discharges. Annual loads of dissolved solids ranged from 21,100 tons in the South Fork to about 480,000 tons at the most downstream site. Total solids transport in the White River was mostly as dissolved solids at upstream sites and mostly as suspended sediment at downstream sites. Concentration ranges of nutrients and trace constituents were determined.

Enhanced solubility and targeted delivery of curcumin by lipopeptide micelles.

PubMed

Liang, Ju; Wu, Wenlan; Lai, Danyu; Li, Junbo; Fang, Cailin

2015-01-01

A lipopeptide (LP)-containing KKGRGDS as the hydrophilic heads and lauric acid (C12) as the hydrophobic tails has been designed and prepared by standard solid-phase peptide synthesis technique. LP can self-assemble into spherical micelles with the size of ~30 nm in PBS (phosphate buffer saline) (pH 7.4). Curcumin-loaded LP micelles were prepared in order to increase the water solubility, sustain the releasing rate, and improve the tumor targeted delivery of curcumin. Water solubility, cytotoxicity, in vitro release behavior, and intracellular uptake of curcumin-loaded LP micelles were investigated. The results showed that LP micelles can increase the water solubility of curcumin 1.1 × 10(3) times and sustain the release of curcumin in a low rate. Curcumin-loaded LP micelles showed much higher cell inhibition than free curcumin on human cervix carcinoma (HeLa) and HepG2 cells. When incubating these curcumin-loaded micelles with HeLa and COS7 cells, due to the over-expression of integrins on cancer cells, the micelles can efficiently use the tumor-targeting function of RGD (functionalized peptide sequences: Arg-Gly-Asp) sequence to deliver the drug into HeLa cells, and better efficiency of the self-assembled LP micelles for curcumin delivery than crude curcumin was also confirmed by LCSM (laser confocal scanning microscope) assays. Combined with the enhanced solubility and higher cell inhibition, LP micelles reported in this study may be promising in clinical application for targeted curcumin delivery.

Improved estimates of filtered total mercury loadings and total mercury concentrations of solids from potential sources to Sinclair Inlet, Kitsap County, Washington

USGS Publications Warehouse

Paulson, Anthony J.; Conn, Kathleen E.; DeWild, John F.

2013-01-01

Previous investigations examined sources and sinks of mercury to Sinclair Inlet based on historic and new data. This included an evaluation of mercury concentrations from various sources and mercury loadings from industrial discharges and groundwater flowing from the Bremerton naval complex to Sinclair Inlet. This report provides new data from four potential sources of mercury to Sinclair Inlet: (1) filtered and particulate total mercury concentrations of creek water during the wet season, (2) filtered and particulate total mercury releases from the Navy steam plant following changes in the water softening process and discharge operations, (3) release of mercury from soils to groundwater in two landfill areas at the Bremerton naval complex, and (4) total mercury concentrations of solids in dry dock sumps that were not affected by bias from sequential sampling. The previous estimate of the loading of filtered total mercury from Sinclair Inlet creeks was based solely on dry season samples. Concentrations of filtered total mercury in creek samples collected during wet weather were significantly higher than dry weather concentrations, which increased the estimated loading of filtered total mercury from creek basins from 27.1 to 78.1 grams per year. Changes in the concentrations and loading of filtered and particulate total mercury in the effluent of the steam plant were investigated after the water softening process was changed from ion-exchange to reverse osmosis and the discharge of stack blow-down wash began to be diverted to the municipal water-treatment plant. These changes reduced the concentrations of filtered and particulate total mercury from the steam plant of the Bremerton naval complex, which resulted in reduced loadings of filtered total mercury from 5.9 to 0.15 grams per year. Previous investigations identified three fill areas on the Bremerton naval complex, of which the western fill area is thought to be the largest source of mercury on the base. Studies of groundwater in the other two fill areas were conducted under worst-case higher high tidal conditions. A December 2011 study found that concentrations of filtered total mercury in the well in the fill area on the eastern boundary of the Bremerton naval complex were less than or equal to 11 nanograms per liter, indicating that releases from the eastern area were unlikely. In addition, concentrations of total mercury of solids were low (<3 milligrams per kilogram). In contrast, data from the November 2011 study indicated that the concentrations of filtered total mercury in the well located in the central fill area had tidally influenced concentrations of up to 500 nanograms per liter and elevated concentrations of total mercury of solids (29–41 milligrams per kilogram). This suggests that releases from this area, which has not been previously studied in detail, may be substantial. Previous measurements of total mercury of suspended solids in the dry dock discharges revealed high concentration of total mercury when suspended-solids concentrations were low. However, this result could have been owing to bias from sequential sampling during changing suspended‑solids concentrations. Sampling of two dry dock systems on the complex in a manner that precluded this bias confirmed that suspended-solids concentrations and total mercury concentrations of suspended solids varied considerably during pumping cycles. These new data result in revised estimates of solids loadings from the dry docks. Although most of the solids discharged by the dry docks seem to be recycled Operable Unit B Marine sediment, a total of about 3.2 metric tons of solids per year containing high concentrations of total mercury were estimated to be discharged by the two dry dock systems. A simple calculation, in which solids (from dry docks, the steam plant, and tidal flushing of the largest stormwater drain) are widely dispersed throughout Operable Unit B Marine, suggests that Bremerton naval complex solids would likely have little effect on Operable Unit B Marine sediments because of high concentrations of mercury already present in the sediment.

Why earthquakes correlate weakly with the solid Earth tides: Effects of periodic stress on the rate and probability of earthquake occurrence

USGS Publications Warehouse

Beeler, N.M.; Lockner, D.A.

2003-01-01

We provide an explanation why earthquake occurrence does not correlate well with the daily solid Earth tides. The explanation is derived from analysis of laboratory experiments in which faults are loaded to quasiperiodic failure by the combined action of a constant stressing rate, intended to simulate tectonic loading, and a small sinusoidal stress, analogous to the Earth tides. Event populations whose failure times correlate with the oscillating stress show two modes of response; the response mode depends on the stressing frequency. Correlation that is consistent with stress threshold failure models, e.g., Coulomb failure, results when the period of stress oscillation exceeds a characteristic time tn; the degree of correlation between failure time and the phase of the driving stress depends on the amplitude and frequency of the stress oscillation and on the stressing rate. When the period of the oscillating stress is less than tn, the correlation is not consistent with threshold failure models, and much higher stress amplitudes are required to induce detectable correlation with the oscillating stress. The physical interpretation of tn is the duration of failure nucleation. Behavior at the higher frequencies is consistent with a second-order dependence of the fault strength on sliding rate which determines the duration of nucleation and damps the response to stress change at frequencies greater than 1/tn. Simple extrapolation of these results to the Earth suggests a very weak correlation of earthquakes with the daily Earth tides, one that would require >13,000 earthquakes to detect. On the basis of our experiments and analysis, the absence of definitive daily triggering of earthquakes by the Earth tides requires that for earthquakes, tn exceeds the daily tidal period. The experiments suggest that the minimum typical duration of earthquake nucleation on the San Andreas fault system is ???1 year.

Time-Dependent Fatigue Crack Propagation Behavior of Two Solid-Solution-Strengthened Ni-Based Superalloys—INCONEL 617 and HAYNES 230

NASA Astrophysics Data System (ADS)

Ma, Longzhou; Roy, Shawoon K.; Hasan, Muhammad H.; Pal, Joydeep; Chatterjee, Sudin

2012-02-01

The fatigue crack propagation (FCP) as well as the sustained loading crack growth (SLCG) behavior of two solid-solution-strengthened Ni-based superalloys, INCONEL 617 (Special Metals Corporation Family of Companies) and HAYNES 230 (Haynes International, Inc., Kokomo, IN), were studied at increased temperatures in laboratory air under a constant stress-intensity-factor ( K) condition. The crack propagation tests were conducted using a baseline cyclic triangular waveform with a frequency of 1/3 Hz. Various hold times were imposed at the maximum load of a fatigue cycle to study the hold time effect. The results show that a linear elastic fracture mechanics (LEFM) parameter, stress intensity factor ( K), is sufficient to describe the FCP and SLCG behavior at the testing temperatures ranging from 873 K to 1073 K (600 °C to 800 °C). As observed in the precipitation-strengthened superalloys, both INCONEL 617 and HAYNES 230 exhibited the time-dependent FCP, steady SLCG behavior, and existence of a damage zone ahead of crack tip. A thermodynamic equation was adapted to correlate the SLCG rates to determine thermal activation energy. The fracture modes associated with crack propagation behavior were discussed, and the mechanism of time-dependent FCP as well as SLCG was identified. Compared with INCONEL 617, the lower crack propagation rates of HAYNES 230 under the time-dependent condition were ascribed to the different fracture mode and the presence of numerous W-rich M6C-type and Cr-rich M23C6-type carbides. Toward the end, a phenomenological model was employed to correlate the FCP rates at cycle/time-dependent FCP domain. All the results suggest that an environmental factor, the stress assisted grain boundary oxygen embrittlement (SAGBOE) mechanism, is mainly responsible for the accelerated time-dependent FCP rates of INCONEL 617 and HAYNES 230.

Variability of surface-water quantity and quality and shallow groundwater levels and quality within the Rio Grande Project Area, New Mexico and Texas, 2009–13

USGS Publications Warehouse

Driscoll, Jessica M.; Sherson, Lauren R.

2016-03-15

Drought conditions during the study period of January 1, 2009, to September 30, 2013, caused a reduction in surface-water releases from water-supply storage infrastructure of the Rio Grande Project, which led to changes in surface-water and groundwater (conjunctive) use in downstream agricultural alluvial valleys. Surface water and groundwater in the agriculturally dominated alluvial Rincon and Mesilla Valleys were investigated in this study to measure the influence of drought and subsequent change in conjunctive water use on quantity and quality of these water resources. In 2013, the U.S. Geological Survey, in cooperation with the New Mexico Environment Department and the New Mexico Interstate Stream Commission, began a study to (1) calculate dissolved-solids loads over the study period at streamgages in the study area where data are available, (2) assess the temporal variability of dissolved-solids loads at and between each streamgage where data are available, and (3) relate the spatiotemporal variability of shallow groundwater data (groundwater levels and quality) within the alluvial valleys of the study area to spatiotemporal variability of surface-water data over the study period. This assessment included the calculation of surface-water dissolved-solids loads at streamgages as well as a mass-balance approach to measure the change in salt load between these streamgages. Bimodal surface-water discharge data led to a temporally-dynamic volumetric definition of release and nonrelease seasons. Continuous surface-water discharge and water-quality data from three streamgages on the Rio Grande were used to calculate daily dissolved-solids loads over the study period, and the results were aggregated annually and seasonally. Results show the majority of dissolved-solids loading occurs during release season; however, decreased duration of the release season over the 5-year study period has resulted in a decrease of the total annual loads at each streamgage. Calculation of the change of salt loads using a mass-balance approach was applied between streamgages. Results from these calculations suggest differing responses to releases in the Rincon and Mesilla Valleys over the period of study; there is a decreasing sink of salt in the Rincon Valley whereas there is an increasing sink of salt in the Mesilla Valley. Daily groundwater-level and water-quality data from shallow wells within the two alluvial valleys show spatial heterogeneity of water quality over the study period. Mass-balance salt-loading trends during the study period are similar to previous trends during the 1950s drought as well as a wet period in the 1980s. The similarity of salt-loading trends from the 1950s, 1980s, and 2000s independent of the climate indicates salt loading in this hydrologic setting may be driven by water-use practices rather than a single climatic variable.

Hybrid Direct-Current Circuit Breaker

NASA Technical Reports Server (NTRS)

Wang, Ruxi (Inventor); Premerlani, William James (Inventor); Caiafa, Antonio (Inventor); Pan, Yan (Inventor)

2017-01-01

A circuit breaking system includes a first branch including at least one solid-state snubber; a second branch coupled in parallel to the first branch and including a superconductor and a cryogenic contactor coupled in series; and a controller operatively coupled to the at least one solid-state snubber and the cryogenic contactor and programmed to, when a fault occurs in the load circuit, activate the at least one solid-state snubber for migrating flow of the electrical current from the second branch to the first branch, and, when the fault is cleared in the load circuit, activate the cryogenic contactor for migrating the flow of the electrical current from the first branch to the second branch.

Sediment Transport Processes During Flood Events in the Middle LoireGauging and First Results

NASA Astrophysics Data System (ADS)

Gautier, J.; Rodrigues, S.; Juge, P.; Peters, J.

2008-12-01

A hydraulic and sediment transport survey campaign was organised in March 2007 on the Loire River, at the Bréhémont site. The aim was to collect data useful for the understanding of fluviomorphological mechanisms. A survey procedure, established at the end of the 1960's and relying on a follow-up bathymetric surveys and ancient sediments samplers was combined with modern technologies such as DGPS satellite positioning and ADCP flow gauging. The survey campaign allowed quantifying the sediment transport rates of the size fractions larger than 50 microns. The results confirm the earlier made hypothesis concerning the existence of a sediment load moving close to the bottom and distinct from the suspended load as described in the theories. This load was called "morphological" and is composed of solids having sizes between those of the river bed and those moving in suspension at higher elevations. This statement, made on the basis of surveys on other large streams in Africa, Asia and the America's questions the concepts on which have been based the majority of the sediment transport theories. The analysis shows also that the rate of bedload transport can be very high up to 60% in some verticals and nearly 50% on all a profil, that is much more than the rate usually admits. The present surveys show that campaigns as these are necessary in order to comprehend the processes, a condition prior to investigating solutions.

Effect of temperature on continuous dry fermentation of swine manure.

PubMed

Deng, Liangwei; Chen, Chuang; Zheng, Dan; Yang, Hongnan; Liu, Yi; Chen, Ziai

2016-07-15

Laboratory-scale experiments were performed on the dry digestion of solid swine manure in a semi-continuous mode using 4.5 L down plug-flow anaerobic reactors with an organic loading rate of 3.46 kg volatile solids (VS) m(-3) d(-1) to evaluate the effects of temperature (15, 25 and 35 °C). At 15 °C, biogas production was the poorest due to organic overload and acidification, with a methane yield of 0.036 L CH4 g(-1) VS added and a volumetric methane production rate of 0.125 L CH4 L(-1) d(-1). The methane yield and volumetric methane production rate at 25 °C (0.226 L CH4 g(-1) VS added and 0.783 L CH4 L(-1) d(-1), respectively) were 6.24 times higher than those at 15 °C. However, the methane yield (0.237 L CH4 g(-1) VS added) and the volumetric methane production rate (0.821 L CH4 L(-1) d(-1)) at 35 °C were only 4.86% higher than those at 25 °C, which indicated similar results were obtained at 25 °C and 35 °C. The lower biogas production at 35 °C in dry digestion compared with that in wet digestion could be attributed to ammonia inhibition. For a single pig farm, digestion of solid manure is accomplished in small-scale domestic or small-farm bioreactors, for which operating temperatures of 35 °C are sometimes difficult to achieve. Considering biogas production, ammonia inhibition and net energy recovery, an optimum temperature for dry digestion of solid swine manure is 25 °C. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fate and transport of some selected PhACs in a river receiving a high load of treated sewage

NASA Astrophysics Data System (ADS)

Bendz, D.; Ginn, T. R.; Paxeus, N.

2003-04-01

Pharmaceutical active compounds (PhACs) have lately been acknowledged to constitute a risk for humans and for the terrestrial and aquatic environment. Human and veterinary applications are the main sources of PhACs in the environment and the major pathway are excretion and discharge to the environment. Sewage treatment plants (STPs) play a crucial role for the introduction of the human PhACs in the environment through its removal efficiency and by separating these compounds into two exposure pathways associated with the aquatic and the solid (sludge) phase, respectively. Actually, STPs are recognized as being the main point discharge sources of human PhACs to the aquatic environment. In this study the fate and transport of a selected human PhACs belonging to different therapeutic classes (NSAIDs- non-steroidal antiinflamatory drugs, lipid regulators, antiepileptics, antibiotics and &beta-blockers) are investigated in a small river in the very south of Sweden receiving a high load of treated wastewater. In addition to the PhACs, triclosan (commonly used biocide) was included in this study. Water samples were taken of incoming and outgoing wastewater from the treatment plant, at the effluent in the river, and along the river up to 8 kilometers downstream were the river flows into the sea. After enrichment by solid-phase extraction the compounds were analyzed using GC-MS (methylated derivatives) or LC-MS/MS. In addition to the target compounds a screening analysis of the extracts revealed the presence of other wastewater related pollutants (caffeine, flame retardants, antioxidants). Several of the investigated substances demonstrate a surprising persistence in the aquatic environment. This emphasizes the need for a broader view on the concept of persistence by taking into account the recharge/loading rate in addition to removal mechanisms; transformation, volatility and physical sequestration by solids and the influence of different environmental media (Soil organic matter, mineralogy, macroscopic physical properties etc) in various hydrological systems.

Note: All solid-state high repetitive sub-nanosecond risetime pulse generator based on bulk gallium arsenide avalanche semiconductor switches.

PubMed

Hu, Long; Su, Jiancang; Ding, Zhenjie; Hao, Qingsong; Fan, Yajun; Liu, Chunliang

2016-08-01

An all solid-state high repetitive sub-nanosecond risetime pulse generator featuring low-energy-triggered bulk gallium arsenide (GaAs) avalanche semiconductor switches and a step-type transmission line is presented. The step-type transmission line with two stages is charged to a potential of 5.0 kV also biasing at the switches. The bulk GaAs avalanche semiconductor switch closes within sub-nanosecond range when illuminated with approximately 87 nJ of laser energy at 905 nm in a single pulse. An asymmetric dipolar pulse with peak-to-peak amplitude of 9.6 kV and risetime of 0.65 ns is produced on a resistive load of 50 Ω. A technique that allows for repetition-rate multiplication of pulse trains experimentally demonstrated that the parallel-connected bulk GaAs avalanche semiconductor switches are triggered in sequence. The highest repetition rate is decided by recovery time of the bulk GaAs avalanche semiconductor switch, and the operating result of 100 kHz of the generator is discussed.

Exploitation of rapid acidification phenomena of food waste in reducing the hydraulic retention time (HRT) of high rate anaerobic digester without conceding on biogas yield.

PubMed

Kuruti, Kranti; Begum, Sameena; Ahuja, Shruti; Anupoju, Gangagni Rao; Juntupally, Sudharshan; Gandu, Bharath; Ahuja, Devender Kumar

2017-02-01

The aim of the present work was to study and infer a full scale experience on co-digestion of 1000kg of FW (400kg cooked food waste and 600kg uncooked food waste) and 2000L of rice gruel (RG) on daily basis based on a high rate biomethanation technology called "Anaerobic gas lift reactor" (AGR). The pH of raw substrate was low (5.2-5.5) that resulted in rapid acidification phenomena with in 12h in the feed preparation tank that facilitated to obtain a lower hydraulic residence time (HRT) of 10days. At full load, AGR was fed with 245kg of total solids, 205kg of volatile solids (167kg of organic matter in terms of chemical oxygen demand) which resulted in the generation of biogas and bio manure of 140m 3 /day and 110kg/day respectively. The produced biogas replaced 60-70kg of LPG per day. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fenofibrate Nanocrystals Embedded in Oral Strip-Films for Bioavailability Enhancement

PubMed Central

Barvaliya, Manish; Zhang, Lu; Anovadiya, Ashish; Brahmbhatt, Harshad; Paul, Parimal; Tripathi, Chandrabhanu

2018-01-01

The aim of the present study was to make a fenofibrate (FNB) nanocrystal (NC) by wet media milling, characterizations and formulates into oral strip-films (OSFs). Mechanical properties, redispersion study, and solid-state characterizations results suggested that reduction of drug crystal size at nanoscale and incorporation into OSFs does not affect the solid-state properties of the drug. In vitro dissolution kinetics showed enhanced dissolution rate was easily manipulated by changing the thickness of the OSF. In situ UV-imaging was used to monitor drug dissolution qualitatively and quantitatively in real time. Results confirm that the intrinsic dissolution rates and surface drug concentration measured with this device were in agreement with the USP-IV dissolution profiles. In vivo pharmacokinetics in rabbits showed a significant difference in the pharmacokinetics parameter (1.4 fold increase bioavailability) of FNB NC-loaded OSFs as compared to the marketed formulation “Tricor” and as-received (pristine) drug. This approach of drug nanocrystallization and incorporation into OSFs may have significant applications in cost-effective tools for bioavailability enhancement of FNB. PMID:29438297

Flashlamp radiation recycling for enhanced pumping efficiency and reduced thermal load

DOEpatents

Jancaitis, Kenneth S.; Powell, Howard T.

1989-01-01

A method for recycling laser flashlamp radiation in selected wavelength ranges to decrease thermal loading of the solid state laser matrix while substantially maintaining the pumping efficiency of the flashlamp.

Removal of ammoniacal nitrogen from landfill leachate by irrigation onto vegetated treatment planes.

PubMed

Tyrrel, S F; Leeds-Harrison, P B; Harrison, K S

2002-01-01

Leachate is a contaminated liquor resulting from the disposal of solid and liquid wastes at landfill sites that must be treated before discharge. Vegetated leachate treatment planes have been used at landfill sites in the UK but have received little scientific attention. This paper describes studies of model leachate treatment planes with a focus on the removal of ammoniacal nitrogen (NH3-N). Small-scale and field-scale experimental treatment planes were constructed. filled with clay loam soil and vegetated with grass (Agrostis stolonifera). Landfill leachate was applied at hydraulic loading rates ranging from 17-217l/m2/d. An exponential relationship was used to characterise the pattern of NH3-N removal. No relationship was observed between the hydraulic loading rate and the NH3-N removal rate constants (R2 = 0.0039). The daily specific NH3-N mass removal rate was found to be linearly related to the NH3-N concentration at the start of that day of treatment (R2 = 0.35). Possible causes of variation in the rate of NH3-N removal between experiments are discussed. A simple inorganic nitrogen balance indicated that the mass of N-H3-N and NO2-N removed was not accounted for by NO3-N production. Explanations for this apparent nitrogen deficit are discussed.

Modeling urban storm rainfall runoff from diverse underlying surfaces and application for control design in Beijing.

PubMed

Ouyang, Wei; Guo, Bobo; Hao, Fanghua; Huang, Haobo; Li, Junqi; Gong, Yongwei

2012-12-30

Managing storm rainfall runoff is paramount in semi-arid regions with urban development. In Beijing, pollution prevention in urban storm runoff and storm water utilization has been identified as the primary strategy for urban water management. In this paper, we sampled runoff during storm rainfall events and analyzed the concentration of chemical oxygen demand (COD), total suspended solids (TSS) and total phosphorus (TP) in the runoff. Furthermore, the first flush effect of storm rainfall from diverse underlying surfaces was also analyzed. With the Storm Water Management Model (SWMM), the different impervious rates of underlying surfaces during the storm runoff process were expressed. The removal rates of three typical pollutants and their interactions with precipitation and underlying surfaces were identified. From these rates, the scenarios regarding the urban storm runoff pollution loading from different designs of underlying previous rates were assessed with the SWMM. First flush effect analysis showed that the first 20% of the storm runoff should be discarded, which can help in utilizing the storm water resource. The results of this study suggest that the SWMM can express in detail the storm water pollution patterns from diverse underlying surfaces in Beijing, which significantly affected water quality. The scenario analysis demonstrated that impervious rate adjustment has the potential to reduce runoff peak and decrease pollution loading. Copyright © 2012 Elsevier Ltd. All rights reserved.

Characterization of Solid Polymers, Ceramic Gap Filler, and Closed-Cell Polymer Foam Using Low-Load Test Methods

NASA Technical Reports Server (NTRS)

Herring, Helen M.

2008-01-01

Various solid polymers, polymer-based composites, and closed-cell polymer foam are being characterized to determine their mechanical properties, using low-load test methods. The residual mechanical properties of these materials after environmental exposure or extreme usage conditions determines their value in aerospace structural applications. In this experimental study, four separate polymers were evaluated to measure their individual mechanical responses after thermal aging and moisture exposure by dynamic mechanical analysis. A ceramic gap filler, used in the gaps between the tiles on the Space Shuttle, was also tested, using dynamic mechanical analysis to determine material property limits during flight. Closed-cell polymer foam, used for the Space Shuttle External Tank insulation, was tested under low load levels to evaluate how the foam's mechanical properties are affected by various loading and unloading scenarios.

Stepwise encapsulation and controlled two-stage release system for cis-Diamminediiodoplatinum

PubMed Central

Chen, Yun; Li, Qian; Wu, Qingsheng

2014-01-01

cis-Diamminediiodoplatinum (cis-DIDP) is a cisplatin-like anticancer drug with higher anticancer activity, but lower stability and price than cisplatin. In this study, a cis-DIDP carrier system based on micro-sized stearic acid was prepared by an emulsion solvent evaporation method. The maximum drug loading capacity of cis-DIDP-loaded solid lipid nanoparticles was 22.03%, and their encapsulation efficiency was 97.24%. In vitro drug release in phosphate-buffered saline (pH =7.4) at 37.5°C exhibited a unique two-stage process, which could prove beneficial for patients with tumors and malignancies. MTT (3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide) assay results showed that cis-DIDP released from cis-DIDP-loaded solid lipid nanoparticles had better inhibition activity than cis-DIDP that had not been loaded. PMID:25061294

Exploratory Investigation of Failure Mechanisms in Transition Regions between Solid Laminates and X-cor(registered tm) Truss Sandwich

NASA Technical Reports Server (NTRS)

OBrien, T. Kevin; Paris, Isabelle L.

2004-01-01

Small sub-component specimens consisting of solid laminates at the ends that transition to X-cor(R) truss sandwich in the center, were tested in a combination of three point bending, uni-axial tension, and combined tension and bending. The failure process in the transition region was documented for each loading using digital video and high-resolution cameras. For the 3-point bending tests, most of the deformation occurred in the solid laminate regions on either end of the specimen. Some pin debonding from the skin of the X-cor(R) truss sandwich was observed in the transition region and was accompanied by audible "pings" throughout the loading. Tension loaded specimens failed in the sandwich skin in the middle of the gage length, accompanied by separation of the sandwich core from the back skin and by delamination between the top skin and bottom skin at the transition region. The pinging associated with pin debonding occurred as the load was increased. However, the frequency of the pinging exceeded any visual observations of pin debonding in the video of the transition region. For specimens tested in combined tension and bending, the greatest amount of pinging occurred during initial application of the axial load. High-resolution images in the transition region indicated that the pinging corresponded to pins debonding and buckling due to the through-thickness Poisson contraction of the specimen. This buckling continued to a much smaller extent as the transverse load was applied.

Enhanced kinetic solubility profiles of indomethacin amorphous solid dispersions in poly(2-hydroxyethyl methacrylate) hydrogels.

PubMed

Sun, Dajun D; Ju, Tzu-chi Rob; Lee, Ping I

2012-05-01

The feasibility of forming solid molecular dispersions of poorly water-soluble drugs in crosslinked poly(2-hydroethyl methacrylate) (PHEMA) hydrogel has recently been reported by our group. The purpose of the present study is to investigate the extent of enhancement of kinetic solubility of amorphous solid dispersions (ASDs) of indomethacin (IND) in crosslinked PHEMA hydrogels as compared with those based on conventional water-soluble polymer carriers. Our results show that under non-sink conditions, the initial solubility enhancement is higher for ASDs based on polyvinylpyrrolidone (PVP) and hydroxypropylmethylcellulose acetate succinate (HMPCAS), but the ability to maintain this solubility enhancement at longer times is better for ASDs based on PHEMA over a period of 24h with the extent of solubility enhancement of IND ASDs in PHEMA falling between those in PVP and HPMCAS at 10.0% IND loading after 6h and outperforming those in PVP and HPMCAS at 32.9% IND loading after 8h. The observed kinetic solubility profiles reflect the fact that the amorphous IND is released from PHEMA by a different mechanism than those from water-soluble polymer carriers. In this case, the dissolution of IND ASD from water-soluble PVP and HPMCAS is almost instantaneous, resulting in an initial surge of IND concentration followed by a sharp decline due to the nucleation and crystallization events triggered by the rapid build-up of drug supersaturation. On the other hand, the dissolution of IND ASD from insoluble crosslinked PHEMA hydrogel beads is less rapid as it is regulated by a feedback-controlled diffusion mechanism, thus avoiding a sudden surge of supersaturation in the dissolution medium. The absence of an apparent decline in drug concentration during dissolution from IND-PHEMA ASD further reflects the diminished nucleation and crystallization events during IND dissolution from hydrogel-based solid molecular dispersions. Based on the XRD analyses, a threshold IND loading level of about 34% in PHEMA has been identified, above which amorphous to crystalline transition tends to occur. Also, by selecting the appropriate particle sizes, immediate to controlled release of IND from IND-PHEMA ASD can be readily achieved as the release rate increases with decreasing PHEMA bead size. Furthermore, a robust physical stability has been demonstrated in IND-PHEMA ASD with no drug precipitation for up to 8 months at IND loadings below 16.7% under direct open cup exposure to accelerated stability conditions (40°C/75% RH). Copyright © 2012 Elsevier B.V. All rights reserved.

On the history of the development of solid-propellant rockets in the Soviet Union

NASA Technical Reports Server (NTRS)

Pobedonostsev, Y. A.

1977-01-01

Pre-World War II Soviet solid-propellant rocket technology is reviewed. Research and development regarding solid composite preparations of pyroxyline TNT powder is described, as well as early work on rocket loading calculations, problems of flight stability, and aircraft rocket launching and ground rocket launching capabilities.

49 CFR 175.900 - Handling requirements for carbon dioxide, solid (dry ice).

Code of Federal Regulations, 2010 CFR

2010-10-01

... (dry ice). 175.900 Section 175.900 Transportation Other Regulations Relating to Transportation PIPELINE....900 Handling requirements for carbon dioxide, solid (dry ice). Carbon dioxide, solid (dry ice) when... operator must ensure that the ground staff is informed that the dry ice is being loaded or is on board the...

49 CFR 175.900 - Handling requirements for carbon dioxide, solid (dry ice).

Code of Federal Regulations, 2013 CFR

2013-10-01

... (dry ice). 175.900 Section 175.900 Transportation Other Regulations Relating to Transportation PIPELINE....900 Handling requirements for carbon dioxide, solid (dry ice). Carbon dioxide, solid (dry ice) when... operator must ensure that the ground staff is informed that the dry ice is being loaded or is on board the...

49 CFR 175.900 - Handling requirements for carbon dioxide, solid (dry ice).

Code of Federal Regulations, 2012 CFR

2012-10-01

... (dry ice). 175.900 Section 175.900 Transportation Other Regulations Relating to Transportation PIPELINE....900 Handling requirements for carbon dioxide, solid (dry ice). Carbon dioxide, solid (dry ice) when... operator must ensure that the ground staff is informed that the dry ice is being loaded or is on board the...

49 CFR 175.900 - Handling requirements for carbon dioxide, solid (dry ice).

Code of Federal Regulations, 2011 CFR

2011-10-01

... (dry ice). 175.900 Section 175.900 Transportation Other Regulations Relating to Transportation PIPELINE....900 Handling requirements for carbon dioxide, solid (dry ice). Carbon dioxide, solid (dry ice) when... operator must ensure that the ground staff is informed that the dry ice is being loaded or is on board the...

49 CFR 175.900 - Handling requirements for carbon dioxide, solid (dry ice).

Code of Federal Regulations, 2014 CFR

2014-10-01

... (dry ice). 175.900 Section 175.900 Transportation Other Regulations Relating to Transportation PIPELINE....900 Handling requirements for carbon dioxide, solid (dry ice). Carbon dioxide, solid (dry ice) when... operator must ensure that the ground staff is informed that the dry ice is being loaded or is on board the...

Optimization of β-carotene loaded solid lipid nanoparticles preparation using a high shear homogenization technique

NASA Astrophysics Data System (ADS)

Triplett, Michael D.; Rathman, James F.

2009-04-01

Using statistical experimental design methodologies, the solid lipid nanoparticle design space was found to be more robust than previously shown in literature. Formulation and high shear homogenization process effects on solid lipid nanoparticle size distribution, stability, drug loading, and drug release have been investigated. Experimentation indicated stearic acid as the optimal lipid, sodium taurocholate as the optimal cosurfactant, an optimum lecithin to sodium taurocholate ratio of 3:1, and an inverse relationship between mixing time and speed and nanoparticle size and polydispersity. Having defined the base solid lipid nanoparticle system, β-carotene was incorporated into stearic acid nanoparticles to investigate the effects of introducing a drug into the base solid lipid nanoparticle system. The presence of β-carotene produced a significant effect on the optimal formulation and process conditions, but the design space was found to be robust enough to accommodate the drug. β-Carotene entrapment efficiency averaged 40%. β-Carotene was retained in the nanoparticles for 1 month. As demonstrated herein, solid lipid nanoparticle technology can be sufficiently robust from a design standpoint to become commercially viable.

Utilization of solid catfish manure waste as carbon and nutrient source for lactic acid production.

PubMed

Shi, Suan; Li, Jing; Blersch, David M

2018-06-01

The aim of this work was to study the solid waste (manure) produced by catfish as a potential feedstock for the production of lactic acid (LA) via fermentation. The solid waste contains high levels of both carbohydrates and nutrients that are sufficient for LA bacteria. Simultaneous saccharification and co-fermentation (SSCF) was applied using enzyme and Lactobacillus pentosus, and different loadings of enzyme and solid waste were tested. Results showed LA concentrations of 35.7 g/L were obtained at 15% solids content of catfish waste. Because of the high nutrient content in the fish waste, it could also be used as supplementary substrate for nitrogen and carbon sources with other lignocellulosic materials. A combined feedstock of catfish waste and paper mill sludge was tested, increasing the final LA concentration to 43.1 g/L at 12% solids loading. The catfish waste was shown to be a potential feedstock to provide both carbon and nutrients for LA production, suggesting its use as a sole substrate or in combination with other lignocellulosic materials.

The effect of shape on the fracture of a soft elastic gel subjected to shear load.

PubMed

Kundan, Krishna Kant; Ghatak, Animangsu

2018-02-21

For brittle solids, the fracture energy is the energy required to create a unit area of new surface through the process of division. For crosslinked materials, it is a function of the intrinsic properties like crosslinking density and bond strength of the crosslinks. Here we show that the energy released due to fracture can depend also on the shape of a joint made of this material. Our experiment involves two gel blocks connected via a thin gel disk. The disk is formed into different regular and exotic shapes, but with identical areas of cross-section. When one of the blocks is sheared with respect to the other, the shear load increases with vertical displacement, eventually causing a fracture at a threshold load. The maximum fracture load is different for different disks and among different regularly shaped disks, it is at a maximum for pentagon and hexagon shapes. The fracture energy release rate of the joint depends also on the aspect ratio (height/width) of the shapes. Our experiments also throw light on possible reasons for such a dependence on the shape of the joints.

Highway-runoff quality, and treatment efficiencies of a hydrodynamic-settling device and a stormwater-filtration device in Milwaukee, Wisconsin

USGS Publications Warehouse

Horwatich, Judy A.; Bannerman, Roger T.; Pearson, Robert

2011-01-01

The treatment efficiencies of two prefabricated stormwater-treatment devices were tested at a freeway site in a high-density urban part of Milwaukee, Wisconsin. One treatment device is categorized as a hydrodynamic-settling device (HSD), which removes pollutants by sedimentation and flotation. The other treatment device is categorized as a stormwater-filtration device (SFD), which removes pollutants by filtration and sedimentation. During runoff events, flow measurements were recorded and water-quality samples were collected at the inlet and outlet of each device. Efficiency-ratio and summation-of-load (SOL) calculations were used to estimate the treatment efficiency of each device. Event-mean concentrations and loads that were decreased by passing through the HSD include total suspended solids (TSS), suspended sediment (SS), total phosphorus (TP), total copper (TCu), and total zinc (TZn). The efficiency ratios for these constituents were 42, 57, 17, 33, and 23 percent, respectively. The SOL removal rates for these constituents were 25, 49, 10, 27, and 16 percent, respectively. Event-mean concentrations and loads that increased by passing through the HSD include chloride (Cl), total dissolved solids (TDS), and dissolved zinc (DZn). The efficiency ratios for these constituents were -347, -177, and 20 percent, respectively. Four constituents—dissolved phosphorus (DP), chemical oxygen demand (COD), total polycyclic aromatic hydrocarbon (PAH), and dissolved copper (DCu)—are not included in the list of computed efficiency ratio and SOL because the variability between sampled inlet and outlet pairs were not significantly different. Event-mean concentrations and loads that decreased by passing through the SFD include TSS, SS, TP, DCu, TCu, DZn, TZn, and COD. The efficiency ratios for these constituents were 59, 90, 40, 21, 66, 23, 66, and 18, respectively. The SOLs for these constituents were 50, 89, 37, 19, 60, 20, 65, and 21, respectively. Two constituents—DP and PAH—are not included in the lists of computed efficiency ratio and SOL because the variability between sampled inlet and outlet pairs were not significantly different. Similar to the HSD, the average efficiency ratios and SOLs for TDS and Cl were negative. Flow rates, high concentrations of SS, and particle-size distributions (PSD) can affect the treatment efficacies of the two devices. Flow rates equal to or greater than the design flow rate of the HSD had minimal or negative removal efficiencies for TSS and SS loads. Similar TSS removal efficiencies were observed at the SFD, but SS was consistently removed throughout the flow regime. Removal efficiencies were high for both devices when concentrations of SS and TSS approached 200 mg/L. A small number of runoff events were analyzed for PSD; the average sand content at the HSD was 33 percent and at the SFD was 71 percent. The 71-percent sand content may reflect the 90-percent removal efficiency of SS at the SFD. Particles retained at the bottom of both devices were largely sand-size or greater.

Identifying and overcoming the effect of mass transfer limitation on decreased yield in enzymatic hydrolysis of lignocellulose at high solid concentrations.

PubMed

Du, Jian; Cao, Yuan; Liu, Guodong; Zhao, Jian; Li, Xuezhi; Qu, Yinbo

2017-04-01

Cellulose conversion decreases significantly with increasing solid concentrations during enzymatic hydrolysis of insoluble lignocellulosic materials. Here, mass transfer limitation was identified as a significant determining factor of this decrease by studying the hydrolysis of delignified corncob residue in shake flask, the most used reaction vessel in bench scale. Two mass transfer efficiency-related factors, mixing speed and flask filling, were shown to correlate closely with cellulose conversion at solid loadings higher than 15% DM. The role of substrate characteristics in mass transfer performance was also significant, which was revealed by the saccharification of two corn stover substrates with different pretreatment methods at the same solid loading. Several approaches including premix, fed-batch operation, and particularly the use of horizontal rotating reactor were shown to be valid in facilitating cellulose conversion via improving mass transfer efficiency at solid concentrations higher than 15% DM. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sintered Cathodes for All-Solid-State Structural Lithium-Ion Batteries

NASA Technical Reports Server (NTRS)

Huddleston, William; Dynys, Frederick; Sehirlioglu, Alp

2017-01-01

All-solid-state structural lithium ion batteries serve as both structural load-bearing components and as electrical energy storage devices to achieve system level weight savings in aerospace and other transportation applications. This multifunctional design goal is critical for the realization of next generation hybrid or all-electric propulsion systems. Additionally, transitioning to solid state technology improves upon battery safety from previous volatile architectures. This research established baseline solid state processing conditions and performance benchmarks for intercalation-type layered oxide materials for multifunctional application. Under consideration were lithium cobalt oxide and lithium nickel manganese cobalt oxide. Pertinent characteristics such as electrical conductivity, strength, chemical stability, and microstructure were characterized for future application in all-solid-state structural battery cathodes. The study includes characterization by XRD, ICP, SEM, ring-on-ring mechanical testing, and electrical impedance spectroscopy to elucidate optimal processing parameters, material characteristics, and multifunctional performance benchmarks. These findings provide initial conditions for implementing existing cathode materials in load bearing applications.

Performance of a 10 kV, 625 kA, 85 kJ energy discharge module utilizing a solid dielectric switch

NASA Astrophysics Data System (ADS)

Richardson, R. A.; Cravey, W. R.; Goerz, D. A.

We have designed and tested an 87-kJ energy discharge system consisting of two 720-(mu)F, 11-kV capacitors discharged through parallel coaxial cables into a 250 nH load. Data will be presented on the current and voltage waveforms, with calculated values of the system inductance and resistance. The bank uses a solid dielectric switch punctured by an explosive bridge wire (EBW) to initiate the discharge. With the capacitors charged to 9 kV, a 625-kA peak current is sent through the load with a ringing frequency of 6.8 kHz. The coaxial cables used to transmit the current to the load are 3 m in length. Both RG-217 and YK-198 cable types were tested, which have an inductance of 74 nH/ft and 35 nH/ft respectively. Normal operation requires that each cable carry 52 kA. The cables were tested to 100 kA each by connecting fewer cables to the load, and gradually increasing the charge voltage. The solid dielectric switch was chosen for high reliability. Details of the switch will be describes and data on its performance will be presented.

The effect of organic loading rate and retention time on hydrogen production from a methanogenic CSTR.

PubMed

Pakarinen, O; Kaparaju, P; Rintala, J

2011-10-01

The possibility of shifting a methanogenic process for hydrogen production by changing the process parameters viz., organic loading rate (OLR) and hydraulic retention time (HRT) was evaluated. At first, two parallel semi-continuously fed continuously stirred tank reactors (CSTR) were operated as methanogenic reactors (M1 and M2) for 78 days. Results showed that a methane yield of 198-218 L/kg volatile solids fed (VS(fed)) was obtained when fed with grass silage at an OLR of 2 kgVS/m³/d and HRT of 30 days. After 78 days of operation, hydrogen production was induced in M2 by increasing the OLR from 2 to 10 kgVS/m³/d and shortening the HRT from 30 to 6 days. The highest H₂ yield of 42 L/kgVS(fed) was obtained with a maximum H₂ content of 24%. The present results thus demonstrate that methanogenic process can be shifted towards hydrogen production by increasing the OLR and decreasing HRT. Copyright © 2011 Elsevier Ltd. All rights reserved.

Evaluation of pollutant loads from stormwater BMPs to receiving water using load frequency curves with uncertainty analysis.

PubMed

Park, Daeryong; Roesner, Larry A

2012-12-15

This study examined pollutant loads released to receiving water from a typical urban watershed in the Los Angeles (LA) Basin of California by applying a best management practice (BMP) performance model that includes uncertainty. This BMP performance model uses the k-C model and incorporates uncertainty analysis and the first-order second-moment (FOSM) method to assess the effectiveness of BMPs for removing stormwater pollutants. Uncertainties were considered for the influent event mean concentration (EMC) and the aerial removal rate constant of the k-C model. The storage treatment overflow and runoff model (STORM) was used to simulate the flow volume from watershed, the bypass flow volume and the flow volume that passes through the BMP. Detention basins and total suspended solids (TSS) were chosen as representatives of stormwater BMP and pollutant, respectively. This paper applies load frequency curves (LFCs), which replace the exceedance percentage with an exceedance frequency as an alternative to load duration curves (LDCs), to evaluate the effectiveness of BMPs. An evaluation method based on uncertainty analysis is suggested because it applies a water quality standard exceedance based on frequency and magnitude. As a result, the incorporation of uncertainty in the estimates of pollutant loads can assist stormwater managers in determining the degree of total daily maximum load (TMDL) compliance that could be expected from a given BMP in a watershed. Copyright © 2012 Elsevier Ltd. All rights reserved.

Comparison of Diafiltration and Size-Exclusion Chromatography to Recover Hemicelluloses From Process Water From Thermomechanical Pulping of Spruce

NASA Astrophysics Data System (ADS)

Andersson, Alexandra; Persson, Tobias; Zacchi, Guido; Stålbrand, Henrik; Jönsson, Ann-Sofi

Hemicelluloses constitute one of the most abundant renewable resources on earth. To increase their utilization, the isolation of hemicelluloses from industrial biomass side-streams would be beneficial. A method was investigated to isolate hemicelluloses from process water from a thermomechanical pulp mill. The method consists of three steps: removal of solids by microfiltration, preconcentration of the hemicelluloses by ultrafiltration, and purification by either size-exclusion chromatography (SEC) or diafiltration. The purpose of the final purification step is to separate hemicelluloses from small oligosaccharides, monosaccharides, and salts. The ratio between galactose, glucose, and mannose in oligo- and polysaccharides after preconcentration was 0.8∶1∶2.8, which is similar to that found in galactoglucomannan. Continuous diafiltration was performed using a composite fluoro polymer membrane with cutoff of 1000 Da. After diafiltration with four diavolumes the purity of the hemicelluloses was 77% (gram oligo- and polysaccharides/ gram total dissolved solids) and the recovery was 87%. Purification by SEC was performed with 5, 20, and 40% sample loadings, respectively and a flow rate of 12 or 25 mL/min (9 or 19 cm/h). The purity of hemicelluloses after SEC was approx 82%, and the recovery was above 99%. The optimal sample load and flow rate were 20% and 25 mL/min, respectively. The process water from thermomechanical pulping of spruce is inexpensive. Thus, the recovery of hemicelluloses is not of main importance. If the purity of 77%, obtained with diafiltration, is sufficient for the utilization of the hemicelluloses, diafiltration probably offers a less expensive alternative in this application.

Anaerobic co-digestion of sewage sludge and food waste.

PubMed

Prabhu, Meghanath S; Mutnuri, Srikanth

2016-04-01

Anaerobic co-digestion of organic matter improves digester operating characteristics and its performance. In the present work, food waste was collected from the institute cafeteria. Two types of sludge (before centrifuge and after centrifuge) were collected from the fluidised bed reactor of the institute treating sewage wastewater. Food waste and sludge were studied for their physico-chemical characteristics, such as pH, chemical oxygen demand, total solids, volatile solids, ammoniacal nitrogen, and total nitrogen. A biomethane potential assay was carried out to find out the optimum mixing ratio of food waste and sludge for anaerobic co-digestion. Results indicated that food waste mixed with sludge in the ratio of 1:2 produced the maximum biogas of 823 ml gVS(-1)(21 days) with an average methane content of 60%. Batch studies were conducted in 5 L lab-glass reactors at a mesophilic temperature. The effect of different substrate loading rates on biogas production was investigated. The mixing ratio of food waste and sludge was 1:2. A loading rate of 1 gVS L d(-1)gave the maximum biogas production of 742 ml g(-1)VS L d(-1)with a methane content of 50%, followed by 2 gVS L d(-1)with biogas of 539 ml g(-1)VS L d(-1) Microbial diversity of the reactor during fed batch studies was investigated by terminal restriction fragment length polymorphism. A pilot-scale co-digestion of food waste and sludge (before centrifuge) indicated the process stability of anaerobic digestion. © The Author(s) 2016.

NMR imaging and hydrodynamic analysis of neutrally buoyant non-Newtonian slurry flows

NASA Astrophysics Data System (ADS)

Bouillard, J. X.; Sinton, S. W.

The flow of solids loaded suspension in cylindrical pipes has been the object of intense experimental and theoretical investigations in recent years. These types of flows are of great interest in chemical engineering because of their important use in many industrial manufacturing processes. Such flows are for example encountered in the manufacture of solid-rocket propellants, advanced ceramics, reinforced polymer composites, in heterogeneous catalytic reactors, and in the pipeline transport of liquid-solids suspensions. In most cases, the suspension microstructure and the degree of solids dispersion greatly affect the final performance of the manufactured product. For example, solid propellant pellets need to be extremely-well dispersed in gel matrices for use as rocket engine solid fuels. The homogeneity of pellet dispersion is critical to allow good uniformity of the burn rate, which in turn affects the final mechanical performance of the engine. Today's manufacturing of such fuels uses continuous flow processes rather than batch processes. Unfortunately, the hydrodynamics of such flow processes is poorly understood and is difficult to assess because it requires the simultaneous measurements of liquid/solids phase velocities and volume fractions. Due to the recent development in pulsed Fourier Transform NMR imaging, NMR imaging is now becoming a powerful technique for the non intrusive investigation of multi-phase flows. This paper reports and exposes a state-of-the-art experimental and theoretical methodology that can be used to study such flows. The hydrodynamic model developed for this study is a two-phase flow shear thinning model with standard constitutive fluid/solids interphase drag and solids compaction stresses. this model shows good agreement with experimental data and the limitations of this model are discussed.

Performance of a system with full- and pilot-scale sludge drying reed bed units treating septic tank sludge in Brazil.

PubMed

Calderón-Vallejo, Luisa Fernanda; Andrade, Cynthia Franco; Manjate, Elias Sete; Madera-Parra, Carlos Arturo; von Sperling, Marcos

2015-01-01

This study investigated the performance of sludge drying reed beds (SDRB) at full- and pilot-scale treating sludge from septic tanks in the city of Belo Horizonte, Brazil. The treatment units, planted with Cynodon spp., were based on an adaptation of the first-stage of the French vertical-flow constructed wetland, originally developed for treating sewage. Two different operational phases were investigated; in the first one, the full-scale unit was used together with six pilot-scale columns in order to test different feeding strategies. For the second phase, only the full-scale unit was used, including a recirculation of the filtered effluent (percolate) to one of the units of the French vertical wetland. Sludge application was done once a week emptying a full truck, during 25 weeks. The sludge was predominantly diluted, leading to low solids loading rates (median values of 18 kgTS m(-2) year(-1)). Chemical oxygen demand removal efficiency in the full-scale unit was reasonable (median of 71%), but the total solids removal was only moderate (median of 44%) in the full-scale unit without recirculation. Recirculation did not bring substantial improvements in the overall performance. The other loading conditions implemented in the pilot columns also did not show statistically different performances.

Friction and wear of hydrogenated and hydrogen-free diamond-like carbon films: Relative humidity dependent character

NASA Astrophysics Data System (ADS)

Shi, Jing; Gong, Zhenbin; Wang, Yongfu; Gao, Kaixiong; Zhang, Junyan

2017-11-01

In this study, tribological properties of hydrogenated and hydrogen free diamond-like carbon films at various relative humidity (RH) were investigated to understand the friction mechanism in the presence of water molecules. At normal load of 2N, DLC-H film's friction coefficient was 0.06 at RH14% while DLC film's friction coefficient was 0.19 at RH17%. With the increase of RH, their friction coefficient converged to about 0.15. This character remained unaltered when the normal load was 5N. Results show that low friction of DLC-H film at low RH was attributed to the low shear force aroused by graphitic tribofilm at wear care center. However, the high friction of DLC film was mainly endowed by the high adhesive force aroused by σ dangling bonds. At high RH, solid-to-solid contact was isolated by water molecules confined between the counterfaces, where capillary was a dominant factor for friction. In addition to the capillary force, the absence of tribofilm was also accountable. These two factors lead to the level off of friction coefficient for DLC-H and DLC films. Moreover, for both DLC-H and DLC films, tribo-oxidization was proved to be closely related to wear rate with the assist of H2O molecules during sliding.

Experimental study on the 300W class planar type solid oxide fuel cell stack: Investigation for appropriate fuel provision control and the transient capability of the cell performance

NASA Astrophysics Data System (ADS)

Komatsu, Y.; Brus, G.; Kimijima, S.; Szmyd, J. S.

2012-11-01

The present paper reports the experimental study on the dynamic behavior of a solid oxide fuel cell (SOFC). The cell stack consists of planar type cells with standard power output 300W. A Major subject of the present study is characterization of the transient response to the electric current change, assuming load-following operation. The present studies particularly focus on fuel provision control to the load change. Optimized fuel provision improves power generation efficiency. However, the capability of SOFC must be restricted by a few operative parameters. Fuel utilization factor, which is defined as the ratio of the consumed fuel to the supplied fuel is adopted for a reference in the control scheme. The fuel flow rate was regulated to keep the fuel utilization at 50%, 60% and 70% during the current ramping. Lower voltage was observed with the higher fuel utilization, but achieved efficiency was higher. The appropriate mass flow control is required not to violate the voltage transient behavior. Appropriate fuel flow manipulation can contribute to moderate the overshoot on the voltage that may appear to the current change. The overshoot on the voltage response resulted from the gradual temperature behavior in the SOFC stack module.

Measurements of stiff-material compliance on the nanoscale using ultrasonic force microscopy

NASA Astrophysics Data System (ADS)

Dinelli, F.; Biswas, S. K.; Briggs, G. A. D.; Kolosov, O. V.

2000-05-01

Ultrasonic force microscopy (UFM) was introduced to probe nanoscale mechanical properties of stiff materials. This was achieved by vibrating the sample far above the first resonance of the probing atomic force microscope cantilever where the cantilever becomes dynamically rigid. By operating UFM at different set force values, it is possible to directly measure the absolute values of the tip-surface contact stiffness. From this an evaluation of surface elastic properties can be carried out assuming a suitable solid-solid contact model. In this paper we present curves of stiffness as a function of the normal load in the range of 0-300 nN. The dependence of stiffness on the relative humidity has also been investigated. Materials with different elastic constants (such as sapphire lithium fluoride, and silicon) have been successfully differentiated. Continuum mechanics models cannot however explain the dependence of stiffness on the normal force and on the relative humidity. In this high-frequency regime, it is likely that viscous forces might play an important role modifying the tip-surface interaction. Plastic deformation might also occur due to the high strain rates applied when ultrasonically vibrating the sample. Another possible cause of these discrepancies might be the presence of water in between the two bodies in contact organizing in a solidlike way and partially sustaining the load.

A strain of Saccharomyces cerevisiae evolved for fermentation of lignocellulosic biomass displays improved growth and fermentative ability in high solids concentrations and in the presence of inhibitory compounds

PubMed Central

2011-01-01

Background Softwoods are the dominant source of lignocellulosic biomass in the northern hemisphere, and have been investigated worldwide as a renewable substrate for cellulosic ethanol production. One challenge to using softwoods, which is particularly acute with pine, is that the pretreatment process produces inhibitory compounds detrimental to the growth and metabolic activity of fermenting organisms. To overcome the challenge of bioconversion in the presence of inhibitory compounds, especially at high solids loading, a strain of Saccharomyces cerevisiae was subjected to evolutionary engineering and adaptation for fermentation of pretreated pine wood (Pinus taeda). Results An industrial strain of Saccharomyces, XR122N, was evolved using pretreated pine; the resulting daughter strain, AJP50, produced ethanol much more rapidly than its parent in fermentations of pretreated pine. Adaptation, by preculturing of the industrial yeast XR122N and the evolved strains in 7% dry weight per volume (w/v) pretreated pine solids prior to inoculation into higher solids concentrations, improved fermentation performance of all strains compared with direct inoculation into high solids. Growth comparisons between XR122N and AJP50 in model hydrolysate media containing inhibitory compounds found in pretreated biomass showed that AJP50 exited lag phase faster under all conditions tested. This was due, in part, to the ability of AJP50 to rapidly convert furfural and hydroxymethylfurfural to their less toxic alcohol derivatives, and to recover from reactive oxygen species damage more quickly than XR122N. Under industrially relevant conditions of 17.5% w/v pretreated pine solids loading, additional evolutionary engineering was required to decrease the pronounced lag phase. Using a combination of adaptation by inoculation first into a solids loading of 7% w/v for 24 hours, followed by a 10% v/v inoculum (approximately equivalent to 1 g/L dry cell weight) into 17.5% w/v solids, the final strain (AJP50) produced ethanol at more than 80% of the maximum theoretical yield after 72 hours of fermentation, and reached more than 90% of the maximum theoretical yield after 120 hours of fermentation. Conclusions Our results show that fermentation of pretreated pine containing liquid and solids, including any inhibitory compounds generated during pretreatment, is possible at higher solids loadings than those previously reported in the literature. Using our evolved strain, efficient fermentation with reduced inoculum sizes and shortened process times was possible, thereby improving the overall economic viability of a woody biomass-to-ethanol conversion process. PMID:22074982

Mechanical characteristics of box-section beam made of sliced-laminated Asian bamboo (Dendrocalamus asper) in bending failure mode under transversal load

NASA Astrophysics Data System (ADS)

Karyadi, Susanto, Prijono Bagus

2017-09-01

A box-section beam has a larger moment of inertia than solid beam for the same amount of materials, so, it is expected the box-section beams has larger strength and stiffness compared to the solid beam. In other hand, research about the box-section beams, especially from bamboo lamination material, is limited. For the reason the research was done. The research aimed at finding mechanical characteristic of box-section beams made of sliced-laminated Asian bamboo in bending failure mode under transversal load. The results showed that the strength and stiffness of the box-section beams increase according to the increasing moment of inertia. The strength of the box-section beam increase up to ratio between the section height (h) and section width (b) reach 1.50. Larger than the ratio the strength of the beam will decrease. The average of bending stress at the time of beam collapse reached 106.5MPa and the average of flexural of elastic modulus reached 14.504MPa. The serviceability load reached 8.64% of the maximum load. Based on the results it can be concluded that the box-section beams made of sliced-laminated Asian bamboo more efficient in receiving the transversal load compared to the solid beam for the same amount of materials.

Development of an Intermediate-Scale Aerobic Bioreactor to Regenerate Nutrients from Inedible Crop Residues

NASA Technical Reports Server (NTRS)

Finger, Barry W.; Strayer, Richard F.

1994-01-01

Three Intermediate-Scale Aerobic Bioreactors were designed, fabricated, and operated. They utilized mixed microbial communities to bio-degrade plant residues. The continuously stirred tank reactors operated at a working volume of 8 L, and the average oxygen mass transfer coefficient, k(sub L)a, was 0.01 s(exp -1). Mixing time was 35 s. An experiment using inedible wheat residues, a replenishment rate of 0.125/day, and a solids loading rate of 20 gdw/day yielded a 48% reduction in biomass. Bioreactor effluent was successfully used to regenerate a wheat hydroponic nutrient solution. Over 80% of available potassium, calcium, and other minerals were recovered and recycled in the 76-day wheat growth experiment.

The effect of switchgrass loadings on feedstock solubilization and biofuel production by Clostridium thermocellum

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

Verbeke, Tobin J.; Garcia, Gabriela M.; Elkins, James G.

High solids loading fermentations are necessary for the industrialization of lignocellulosic ethanol. To date, only a few studies have investigated the effect of solids loadings on microorganisms of interest for consolidated bioprocessing (CBP). Here, the effect that various switchgrass loadings have on Clostridium thermocellum solubilization and bioconversion are investigated. C. thermocellum was grown for ten days on 10, 25 or 50 g/L switchgrass or Avicel at equivalent glucan loadings. Avicel was completely consumed at all loadings, but total cellulose solubilization decreased from 63% to 37% as switchgrass loadings increased from 10 g/L to 50 g/L. Washed, spent switchgrass could bemore » additionally hydrolyzed and fermented in second-round fermentations suggesting access to fermentable substrates was not the limiting factor at higher feedstock loadings. Fermentations of Avicel or cellobiose using culture medium supplemented with 50% spent fermentation broth identified that compounds present in the samples collected from the 25 or 50 g/L switchgrass loadings were the most inhibitory to continued fermentation. Finally, recalcitrance alone cannot fully account for differences in solubilization and end-production formation between switchgrass and Avicel at increased substrate loadings. Effort to decouple metabolic inhibition from inhibition of hydrolysis suggest that C. thermocellum’s hydrolytic machinery is more vulnerable to inhibition from switchgrass-derived inhibitors than is the bacterium’s metabolism.« less

The effect of switchgrass loadings on feedstock solubilization and biofuel production by Clostridium thermocellum

DOE PAGES

Verbeke, Tobin J.; Garcia, Gabriela M.; Elkins, James G.

2017-11-30

High solids loading fermentations are necessary for the industrialization of lignocellulosic ethanol. To date, only a few studies have investigated the effect of solids loadings on microorganisms of interest for consolidated bioprocessing (CBP). Here, the effect that various switchgrass loadings have on Clostridium thermocellum solubilization and bioconversion are investigated. C. thermocellum was grown for ten days on 10, 25 or 50 g/L switchgrass or Avicel at equivalent glucan loadings. Avicel was completely consumed at all loadings, but total cellulose solubilization decreased from 63% to 37% as switchgrass loadings increased from 10 g/L to 50 g/L. Washed, spent switchgrass could bemore » additionally hydrolyzed and fermented in second-round fermentations suggesting access to fermentable substrates was not the limiting factor at higher feedstock loadings. Fermentations of Avicel or cellobiose using culture medium supplemented with 50% spent fermentation broth identified that compounds present in the samples collected from the 25 or 50 g/L switchgrass loadings were the most inhibitory to continued fermentation. Finally, recalcitrance alone cannot fully account for differences in solubilization and end-production formation between switchgrass and Avicel at increased substrate loadings. Effort to decouple metabolic inhibition from inhibition of hydrolysis suggest that C. thermocellum’s hydrolytic machinery is more vulnerable to inhibition from switchgrass-derived inhibitors than is the bacterium’s metabolism.« less

PHOTOGRAPHER: KSC The first solid rocket booster solid motor segemnts to arrive at KSC, the left and

NASA Technical Reports Server (NTRS)

1980-01-01

PHOTOGRAPHER: KSC The first solid rocket booster solid motor segemnts to arrive at KSC, the left and right hand aft segments are off-loaded into High Bay 4 in the Vehicle Assembly Building and mated to their respective SRB aft skirts. The two aft assemblies will support the entire 150 foot tall solid boosters, in turn supporting the external tank and Orbiter Columbia on the Mobile Launcher Platform, for the first orbital flight test of the Space Shuttle.

Photographer: KSC The first solid rocket booster solid motor segemnts to arrive at KSC, the left and

NASA Technical Reports Server (NTRS)

1980-01-01

Photographer: KSC The first solid rocket booster solid motor segemnts to arrive at KSC, the left and right hand aft segments are off-loaded into High Bay 4 in the Vehicle Assembly Building and mated to their respective SRB aft skirts. The two aft assemblies will support the entire 150 foot tall solid boosters, in turn supporting the external tank and Orbiter Columbia on the Mobile Launcher Platform, for the first orbital flight test of the Space Shuttle.

Hydrolysis-acidogenesis of food waste in solid-liquid-separating continuous stirred tank reactor (SLS-CSTR) for volatile organic acid production.

PubMed

Karthikeyan, Obulisamy Parthiba; Selvam, Ammaiyappan; Wong, Jonathan W C

2016-01-01

The use of conventional continuous stirred tank reactor (CSTR) can affect the methane (CH4) recovery in a two-stage anaerobic digestion of food waste (FW) due to carbon short circuiting in the hydrolysis-acidogenesis (Hy-Aci) stage. In this research, we have designed and tested a solid-liquid-separating CSTR (SLS-CSTR) for effective Hy-Aci of FW. The working conditions were pH 6 and 9 (SLS-CSTR-1 and -2, respectively); temperature-37°C; agitation-300rpm; and organic loading rate (OLR)-2gVSL(-1)day(-1). The volatile fatty acids (VFA), enzyme activities and bacterial population (by qPCR) were determined as test parameters. Results showed that the Hy-Aci of FW at pH 9 produced ∼35% excess VFA as compared to that at pH 6, with acetic and butyric acids as major precursors, which correlated with the high enzyme activities and low lactic acid bacteria. The design provided efficient solid-liquid separation there by improved the organic acid yields from FW. Copyright © 2015 Elsevier Ltd. All rights reserved.

Formation of a disordered solid via a shock-induced transition in a dense particle suspension

NASA Astrophysics Data System (ADS)

Petel, Oren E.; Frost, David L.; Higgins, Andrew J.; Ouellet, Simon

2012-02-01

Shock wave propagation in multiphase media is typically dominated by the relative compressibility of the two components of the mixture. The difference in the compressibility of the components results in a shock-induced variation in the effective volume fraction of the suspension tending toward the random-close-packing limit for the system, and a disordered solid can take form within the suspension. The present study uses a Hugoniot-based model to demonstrate this variation in the volume fraction of the solid phase as well as a simple hard-sphere model to investigate the formation of disordered structures within uniaxially compressed model suspensions. Both models are discussed in terms of available experimental plate impact data in dense suspensions. Through coordination number statistics of the mesoscopic hard-sphere model, comparisons are made with the trends of the experimental pressure-volume fraction relationship to illustrate the role of these disordered structures in the bulk properties of the suspensions. A criterion for the dynamic stiffening of suspensions under high-rate dynamic loading is suggested as an analog to quasi-static jamming based on the results of the simulations.

Lubricant Rheology in Concentrated Contacts

NASA Technical Reports Server (NTRS)

Jacobson, B. O.

1984-01-01

Lubricant behavior in highly stressed situtations shows that a Newtonian model for lubricant rheology is insufficient for explanation of traction behavior. The oil film build up is predicted by using a Newtonian lubricant model except at high slide to roll ratios and at very high loads, where the nonNewtonian behavior starts to be important already outside the Hertzian contact area. Static and dynamic experiments are reported. In static experiments the pressure is applied to the lubricant more than a million times longer than in an EHD contact. Depending on the pressure-temperature history of the experiment the lubricant will become a crystallized or amorphous solid at high pressures. In dynamic experiments, the oil is in an amorphous solid state. Depending on the viscosity, time scale, elasticity of the oil and the bearing surfaces, the oil film pressure, shear strain rate and the type of lubricant, different properties of the oil are important for prediction of shear stresses in the oil. The different proposed models for the lubricant, which describe it to a Newtonian liquid, an elastic liquid, a plastic liquid and an elastic-plastic solid.

Anaerobic co-digestion of sewage sludge and food waste using temperature-phased anaerobic digestion process.

PubMed

Kim, H W; Han, S K; Shin, H S

2004-01-01

This study was performed to overcome the low efficiency of anaerobic digestion of sewage sludge and food waste by combining temperature-phased digestion, sequencing batch operation, and co-digestion technology. It was demonstrated that the temperature-phased anaerobic sequencing batch reactor (TPASBR) system for the co-digestion of sewage sludge and food waste resulted in enhanced volatile solids (VS) reduction and methane production rate. At the organic loading rate (OLR) of 2.7 g VS/l/d, the TPASBR system showed the higher VS reduction (61.3%), CH4 yield (0.28 l/g VS(added)) and CH4 production rate (0.41 l CH4/l/d) than those (0.29 l CH4/l/d) of the mesophilic two-stage ASBR (MTSASBR). In the specific methanogenic activity (SMA) tests on thermophilic biomass of the TPASBR system, the average SMA of acetate (93 ml CH4/gVSS/d) was much higher than those of propionate (46 ml CH4/g VSS/d) and butyrate (76 ml CH4/g VSS/d). Also, higher specific hydrolytic activity (SHA, 217 mg COD/g VSS/d) of the biomass supported fast hydrolysis under thermophilic conditions. The track study revealed that the most active period of the 24 h cycle was between 6 and 12 h. The enhanced performance of the TPASBR system could be attributed to longer solids retention time, fast hydrolysis, higher CH4 conversion rate, and balanced nutrient condition of co-substrate. It was verified that this combination could be a promising and practical alternative for the simultaneous recycling of two types of organic fraction of municipal solid waste (OFMSW) with high stability.

Actinide recovery process

DOEpatents

Muscatello, Anthony C.; Navratil, James D.; Saba, Mark T.

1987-07-28

Process for the removal of plutonium polymer and ionic actinides from aqueous solutions by absorption onto a solid extractant loaded on a solid inert support such as polystyrenedivinylbenzene. The absorbed actinides can then be recovered by incineration, by stripping with organic solvents, or by acid digestion. Preferred solid extractants are trioctylphosphine oxide and octylphenyl-N,N-diisobutylcarbamoylmethylphosphine oxide and the like.

Actinide recovery process

DOEpatents

Muscatello, A.C.; Navratil, J.D.; Saba, M.T.

1985-06-13

Process for the removal of plutonium polymer and ionic actinides from aqueous solutions by absorption onto a solid extractant loaded on a solid inert support such as polystyrene-divinylbenzene. The absorbed actinides can then be recovered by incineration, by stripping with organic solvents, or by acid digestion. Preferred solid extractants are trioctylphosphine oxide and octylphenyl-N,N-diisobutylcarbamoylmethylphosphine oxide and the like. 2 tabs.

Comparison of Contaminant Transport in Agricultural Drainage Water and Urban Stormwater Runoff

PubMed Central

Ranaivoson, Andry Z.; Feyereisen, Gary W.; Rosen, Carl J.; Moncrief, John F.

2016-01-01

Transport of nitrogen and phosphorus from agricultural and urban landscapes to surface water bodies can cause adverse environmental impacts. The main objective of this long-term study was to quantify and compare contaminant transport in agricultural drainage water and urban stormwater runoff. We measured flow rate and contaminant concentration in stormwater runoff from Willmar, Minnesota, USA, and in drainage water from subsurface-drained fields with surface inlets, namely, Unfertilized and Fertilized Fields. Commercial fertilizer and turkey litter manure were applied to the Fertilized Field based on agronomic requirements. Results showed that the City Stormwater transported significantly higher loads per unit area of ammonium, total suspended solids (TSS), and total phosphorus (TP) than the Fertilized Field, but nitrate load was significantly lower. Nitrate load transport in drainage water from the Unfertilized Field was 58% of that from the Fertilized Field. Linear regression analysis indicated that a 1% increase in flow depth resulted in a 1.05% increase of TSS load from the City Stormwater, a 1.07% increase in nitrate load from the Fertilized Field, and a 1.11% increase in TP load from the Fertilized Field. This indicates an increase in concentration with a rise in flow depth, revealing that concentration variation was a significant factor influencing the dynamics of load transport. Further regression analysis showed the importance of targeting high flows to reduce contaminant transport. In conclusion, for watersheds similar to this one, management practices should be directed to load reduction of ammonium and TSS from urban areas, and nitrate from cropland while TP should be a target for both. PMID:27930684

Comparison of Contaminant Transport in Agricultural Drainage Water and Urban Stormwater Runoff.

PubMed

Ghane, Ehsan; Ranaivoson, Andry Z; Feyereisen, Gary W; Rosen, Carl J; Moncrief, John F

2016-01-01

Transport of nitrogen and phosphorus from agricultural and urban landscapes to surface water bodies can cause adverse environmental impacts. The main objective of this long-term study was to quantify and compare contaminant transport in agricultural drainage water and urban stormwater runoff. We measured flow rate and contaminant concentration in stormwater runoff from Willmar, Minnesota, USA, and in drainage water from subsurface-drained fields with surface inlets, namely, Unfertilized and Fertilized Fields. Commercial fertilizer and turkey litter manure were applied to the Fertilized Field based on agronomic requirements. Results showed that the City Stormwater transported significantly higher loads per unit area of ammonium, total suspended solids (TSS), and total phosphorus (TP) than the Fertilized Field, but nitrate load was significantly lower. Nitrate load transport in drainage water from the Unfertilized Field was 58% of that from the Fertilized Field. Linear regression analysis indicated that a 1% increase in flow depth resulted in a 1.05% increase of TSS load from the City Stormwater, a 1.07% increase in nitrate load from the Fertilized Field, and a 1.11% increase in TP load from the Fertilized Field. This indicates an increase in concentration with a rise in flow depth, revealing that concentration variation was a significant factor influencing the dynamics of load transport. Further regression analysis showed the importance of targeting high flows to reduce contaminant transport. In conclusion, for watersheds similar to this one, management practices should be directed to load reduction of ammonium and TSS from urban areas, and nitrate from cropland while TP should be a target for both.

Groundwater and surface-water interaction, water quality, and processes affecting loads of dissolved solids, selenium, and uranium in Fountain Creek near Pueblo, Colorado, 2012–2014

USGS Publications Warehouse

Arnold, L. Rick; Ortiz, Roderick F.; Brown, Christopher R.; Watts, Kenneth R.

2016-11-28

In 2012, the U.S. Geological Survey, in cooperation with the Arkansas River Basin Regional Resource Planning Group, initiated a study of groundwater and surface-water interaction, water quality, and loading of dissolved solids, selenium, and uranium to Fountain Creek near Pueblo, Colorado, to improve understanding of sources and processes affecting loading of these constituents to streams in the Arkansas River Basin. Fourteen monitoring wells were installed in a series of three transects across Fountain Creek near Pueblo, and temporary streamgages were established at each transect to facilitate data collection for the study. Groundwater and surface-water interaction was characterized by using hydrogeologic mapping, groundwater and stream-surface levels, groundwater and stream temperatures, vertical hydraulic-head gradients and ratios of oxygen and hydrogen isotopes in the hyporheic zone, and streamflow mass-balance measurements. Water quality was characterized by collecting periodic samples from groundwater, surface water, and the hyporheic zone for analysis of dissolved solids, selenium, uranium, and other selected constituents and by evaluating the oxidation-reduction condition for each groundwater sample under different hydrologic conditions throughout the study period. Groundwater loads to Fountain Creek and in-stream loads were computed for the study area, and processes affecting loads of dissolved solids, selenium, and uranium were evaluated on the basis of geology, geochemical conditions, land and water use, and evapoconcentration.During the study period, the groundwater-flow system generally contributed flow to Fountain Creek and its hyporheic zone (as a single system) except for the reach between the north and middle transects. However, the direction of flow between the stream, the hyporheic zone, and the near-stream aquifer was variable in response to streamflow and stage. During periods of low streamflow, Fountain Creek generally gained flow from groundwater. However, during periods of high streamflow, the hydraulic gradient between groundwater and the stream temporarily reversed, causing the stream to lose flow to groundwater.Concentrations of dissolved solids, selenium, and uranium in groundwater generally had greater spatial variability than surface water or hyporheic-zone samples, and constituent concentrations in groundwater generally were greater than in surface water. Constituent concentrations in the hyporheic zone typically were similar to or intermediate between concentrations in groundwater and surface water. Concentrations of dissolved solids, selenium, uranium, and other constituents in groundwater samples collected from wells located on the east side of the north monitoring well transect were substantially greater than for other groundwater, surface-water, and hyporheic-zone samples. With one exception, groundwater samples collected from wells on the east side of the north transect exhibited oxic to mixed (oxic-anoxic) conditions, whereas most other groundwater samples exhibited anoxic to suboxic conditions. Concentrations of dissolved solids, selenium, and uranium in surface water generally increased in a downstream direction along Fountain Creek from the north transect to the south transect and exhibited an inverse relation to streamflow with highest concentration occurring during periods of low streamflow and lowest concentrations occurring during periods of high streamflow.Groundwater loads of dissolved solids, selenium, and uranium to Fountain Creek were small because of the small amount of groundwater flowing to the stream under typical low-streamflow conditions. In-stream loads of dissolved solids, selenium, and uranium in Fountain Creek varied by date, primarily in relation to streamflow at each transect and were much larger than computed constituent loads from groundwater. In-stream loads generally decreased with decreases in streamflow and increased as streamflow increased. In-stream loads of dissolved solids and selenium increased between the north and middle transects but generally decreased between the middle and south transects. By contrast, uranium loads generally decreased between the north and middle transects but increased between the middle and south transects. In-stream load differences between transects appear primarily to be related to differences in streamflow. However, because groundwater typically flows to Fountain Creek under low-flow conditions, and groundwater has greater concentrations of dissolved solids, selenium, and uranium than surface water in Fountain Creek, increases in loads between transects likely are affected by inflow of groundwater to the stream, which can account for a substantial proportion of the in-stream load difference between transects. When loads decreased between transects, the primary cause likely was decreased streamflow as a result of losses to groundwater and flow through the hyporheic zone. However, localized groundwater inflow likely attenuated the magnitude by which the in-stream loads decreased.The combination of localized soluble geologic sources and oxic conditions likely is the primary reason for the occurrence of high concentrations of dissolved solids, selenium, and uranium in groundwater on the east side of the north monitoring well transect. To evaluate conditions potentially responsible for differences in water quality and redox conditions, physical characteristics such as depth to water, saturated thickness, screen depth below the water table, screen height above bedrock, and aquifer hydraulic conductivity were compared by using Wilcoxon rank-sum tests. Results indicated no significant difference between depth to water, screen height above bedrock, and hydraulic conductivity for groundwater samples collected from wells on the east side of the north transect and groundwater samples from all other wells. However, saturated thickness and screen depth below the water table both were significantly smaller for groundwater samples collected from wells on the east side of the north transect than for groundwater samples from other wells, indicating that these characteristics might be related to the elevated constituent concentrations found at that location. Similarly, saturated thickness and screen depth below the water table were significantly smaller for groundwater samples under oxic or mixed (oxic-anoxic) conditions than for those under anoxic to suboxic conditions.The greater constituent concentrations at wells on the east side of the north transect also could, in part, be related to groundwater discharge from an unnamed alluvial drainage located directly upgradient from that location. Although the quantity and quality of water discharging from the drainage is not known, the drainage appears to collect water from a residential area located upgradient to the east of the wells, and groundwater could become concentrated in nitrate and other dissolved constituents before flowing through the drainage. High levels of nitrate, whether from anthropogenic or natural geologic sources, could promote more soluble forms of selenium and other constituents by affecting the redox condition of groundwater. Whether oxic conditions at wells on the east side of the north transect are the result of physical characteristics or of groundwater inflow from the alluvial drainage, the oxic conditions appear to cause increased dissolution of minerals from the shallow shale bedrock at that location. Because ratios of hydrogen and oxygen isotopes indicate evaporation likely has not had a substantial effect on groundwater, constituent concentrations at that location likely are not the result of evapoconcentration. 

Diaion HP-2MG modified with 2-(2,6-dichlorobenzylideneamino) benzenethiol as new adsorbent for solid phase extraction and flame atomic absorption spectrometric determination of metal ions.

PubMed

Ghaedi, M; Montazerozohori, M; Haghdoust, S; Zaare, F; Soylak, M

2013-04-01

A solid phase extraction method for enrichment-separation and the determination of cobalt (Co(2+)), copper (Cu(2+)), nickel (Ni(2+)), zinc (Zn(2+)) and lead (Pb(2+)) ions in real samples has been proposed. The influences of some analytical parameters like pH, flow rate, eluent type and interference of matrix ions on recoveries of analytes were optimized. The limits of detection were found in the range of 1.6-3.9 µg L(-1), while preconcentration factor for all understudy metal ions were found to be 166 with loading half time (t 1/2) less than 10 min. The procedure was applied for the enrichment-separation of analyte ions in environmental samples with recoveries higher than 94.8% and relative SD <4.9% (N = 5).

Test data from small solid propellant rocket motor plume measurements (FA-21)

NASA Technical Reports Server (NTRS)

Hair, L. M.; Somers, R. E.

1976-01-01

A program is described for obtaining a reliable, parametric set of measurements in the exhaust plumes of solid propellant rocket motors. Plume measurements included pressures, temperatures, forces, heat transfer rates, particle sampling, and high-speed movies. Approximately 210,000 digital data points and 15,000 movie frames were acquired. Measurements were made at points in the plumes via rake-mounted probes, and on the surface of a large plate impinged by the exhaust plume. Parametric variations were made in pressure altitude, propellant aluminum loading, impinged plate incidence angle and distance from nozzle exit to plate or rake. Reliability was incorporated by continual use of repeat runs. The test setup of the various hardware items is described along with an account of test procedures. Test results and data accuracy are discussed. Format of the data presentation is detailed. Complete data are included in the appendix.

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

Sajgalik, P.; Sedlacek, J.; Lences, Z.

Densification of silicon carbide without any sintering aids by hot-pressing and rapid hot pressing was investigated. Full density (>99% t.d.) has been reached at 1850 °C, a temperature of at least 150-200 °C lower compared to the up to now known solid state sintered silicon carbide powders. Silicon carbide was freeze granulated and heat treated prior the densification. Furthermore, evolution of microstructure, mechanical properties and creep behavior were evaluated and compared to reference ceramics from as received silicon carbide powder as well as those of commercial one. Novel method results in dense ceramics with Vickers hardness and indentation fracture toughnessmore » of 29.0 GPa and 5.25 MPam 1/2, respectively. Moreover, the creep rate of 3.8 x 10 –9 s –1 at 1450 °C and the load of 100 MPa is comparable to the commercial α-SiC solid state sintered at 2150 °C.« less

Validating pollutant load estimates from highways and roads.

DOT National Transportation Integrated Search

2015-12-31

Rain and snowmelt that runs off of roadways carries pollutants. Pollutant event mean concentrations have been developed for various land uses to calculate annual pollutant loads. These were developed for total suspended solids, total phosphorus, and ...

Preparation and characterization of carnauba wax nanostructured lipid carriers containing benzophenone-3.

PubMed

Lacerda, S P; Cerize, N N P; Ré, M I

2011-08-01

Nanostructured lipid carriers (NLCs) are potential active delivery systems based on mixtures of solid lipids and liquid oil. In this paper, aqueous dispersions of NLCs were prepared by a hot high-pressure homogenization technique using carnauba wax as the solid lipid and isodecyl oleate as the liquid oil. The preparation and stability parameters of benzophenone-3-loaded NLCs have been investigated concerning particle size, zeta potential and loading capacity to encapsulate benzophenone-3, a molecular sunscreen. The current investigation illustrates the effect of the composition of the lipid mixture on the entrapment efficiency, in vitro release and stability of benzophenone-3-loaded in these NLCs. A loading capacity of approximately 5% of benzophenone-3 (m(BZ-3) /m(lipids) ) was characteristic of these systems. © 2011 The Authors. ICS © 2011 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Stochastic modeling of total suspended solids (TSS) in urban areas during rain events.

PubMed

Rossi, Luca; Krejci, Vladimir; Rauch, Wolfgang; Kreikenbaum, Simon; Fankhauser, Rolf; Gujer, Willi

2005-10-01

The load of total suspended solids (TSS) is one of the most important parameters for evaluating wet-weather pollution in urban sanitation systems. In fact, pollutants such as heavy metals, polycyclic aromatic hydrocarbons (PAHs), phosphorous and organic compounds are adsorbed onto these particles so that a high TSS load indicates the potential impact on the receiving waters. In this paper, a stochastic model is proposed to estimate the TSS load and its dynamics during rain events. Information on the various simulated processes was extracted from different studies of TSS in urban areas. The model thus predicts the probability of TSS loads arising from combined sewer overflows (CSOs) in combined sewer systems as well as from stormwater in separate sewer systems in addition to the amount of TSS retained in treatment devices in both sewer systems. The results of this TSS model illustrate the potential of the stochastic modeling approach for assessing environmental problems.

Coiled transmission line pulse generators

DOEpatents

McDonald, Kenneth Fox

2010-11-09

Methods and apparatus are provided for fabricating and constructing solid dielectric "Coiled Transmission Line" pulse generators in radial or axial coiled geometries. The pour and cure fabrication process enables a wide variety of geometries and form factors. The volume between the conductors is filled with liquid blends of monomers, polymers, oligomers, and/or cross-linkers and dielectric powders; and then cured to form high field strength and high dielectric constant solid dielectric transmission lines that intrinsically produce ideal rectangular high voltage pulses when charged and switched into matched impedance loads. Voltage levels may be increased by Marx and/or Blumlein principles incorporating spark gap or, preferentially, solid state switches (such as optically triggered thyristors) which produce reliable, high repetition rate operation. Moreover, these Marxed pulse generators can be DC charged and do not require additional pulse forming circuitry, pulse forming lines, transformers, or an a high voltage spark gap output switch. The apparatus accommodates a wide range of voltages, impedances, pulse durations, pulse repetition rates, and duty cycles. The resulting mobile or flight platform friendly cylindrical geometric configuration is much more compact, light-weight, and robust than conventional linear geometries, or pulse generators constructed from conventional components. Installing additional circuitry may accommodate optional pulse shape improvements. The Coiled Transmission Lines can also be connected in parallel to decrease the impedance, or in series to increase the pulse length.

Acceleration effects in solid propellant rocket motors

NASA Technical Reports Server (NTRS)

Langhenry, M. T.

1986-01-01

The performance variations due to acceleration loads imposed on spinning solid propellant rocket motors are investigated. The four potentially most significant modes of acceleration-induced phenomena are identified from a study of the literature and modeled. The four modes are a mechanical mode which deals with deformations of the propellant and case: a thermodynamic mode which covers acceleration-induced combustion phenomena; a stress mode which covers the stressed propellant's effect on burn rate; and a gas dynamic mode which deals with changes in gas flow in the chamber and through the nozzle. Simplified models of each mode are developed or taken from the literature and are added to an internal ballistics evaluation computer program. The resulting analysis is the first to include all of the modes. In order to do this an original analysis of the mechanical and stress modes was necessary. However, the analysis shows that the stress mode is not important for the circular perforated grains studied. The other effects are shown to have a significant influence on solid rocket motor performance. The magnitude of the different mode effects are such that one may not be ignored over the others as has been done in the past. The results of the analysis are compared to published rocket motor data. The comparisons indicate an erosive burning effect that is a function of spin rate. A qualitative explanation of the erosive effect is presented.

Loads of nitrate, phosphorus, and total suspended solids from Indiana watersheds

USGS Publications Warehouse

Bunch, Aubrey R.

2016-01-01

Transport of excess nutrients and total suspended solids (TSS) such as sediment by freshwater systems has led to degradation of aquatic ecosystems around the world. Nutrient and TSS loads from Midwestern states to the Mississippi River are a major contributor to the Gulf of Mexico Hypoxic Zone, an area of very low dissolved oxygen concentration in the Gulf of Mexico. To better understand Indiana’s contribution of nutrients and TSS to the Mississippi River, annual loads of nitrate plus nitrite as nitrogen, total phosphorus, and TSS were calculated for nine selected watersheds in Indiana using the load estimation model, S-LOADEST. Discrete water-quality samples collected monthly by the Indiana Department of Environmental Management’s Fixed Stations Monitoring Program from 2000–2010 and concurrent discharge data from the U. S. Geological Survey streamflow gages were used to create load models. Annual nutrient and TSS loads varied across Indiana by watershed and hydrologic condition. Understanding the loads from large river sites in Indiana is important for assessing contributions of nutrients and TSS to the Mississippi River Basin and in determining the effectiveness of best management practices in the state. Additionally, evaluation of loads from smaller upstream watersheds is important to characterize improvements at the local level and to identify priorities for reduction.

Improved design of anaerobic digesters for household biogas production in indonesia: one cow, one digester, and one hour of cooking per day.

PubMed

Usack, Joseph G; Wiratni, Wiratni; Angenent, Largus T

2014-01-01

A government-sponsored initiative in Indonesia to design and implement low-cost anaerobic digestion systems resulted in 21 full-scale systems with the aim to satisfy the cooking fuel demands of rural households owning at least one cow. The full-scale design consisted of a 0.3 m diameter PVC pipe, which was operated as a conventional plug-flow system. The system generated enough methane to power a cooking stove for ∼ 1 h. However, eventual clogging from solids accumulation inside the bioreactor proved to be a major drawback. Here, we improved the digester configuration to remedy clogging while maintaining system performance. Controlled experiments were performed using four 9-L laboratory-scale digesters operated at a temperature of 27 ± 1 °C, a volatile solids loading rate of 2.0 g VS · L(-1) · day(-1), and a 21-day hydraulic retention time. Two of the digesters were replicates of the original design (control digesters), while the other two digesters included internal mixing or effluent recycle (experimental digesters). The performance of each digester was compared based on methane yields, VS removal efficiencies, and steady-state solids concentrations during an operating period of 311 days. Statistical analyses revealed that internal mixing and effluent recycling resulted in reduced solids accumulation compared to the controls without diminishing methane yields or solids removal efficiencies.

Sustained-releasing hollow microparticles with dual-anticancer drugs elicit greater shrinkage of tumor spheroids.

PubMed

Baek, Jong-Suep; Choo, Chee Chong; Tan, Nguan Soon; Loo, Say Chye Joachim

2017-10-06

Polymeric particulate delivery systems are vastly explored for the delivery of chemotherapeutic agents. However, the preparation of polymeric particulate systems with the capability of providing sustained release of two or more drugs is still a challenge. Herein, poly (D, L-lactic-co-glycolic acid, 50:50) hollow microparticles co-loaded with doxorubicin and paclitaxel were developed through double-emulsion solvent evaporation technique. Hollow microparticles were formed through the addition of an osmolyte into the fabrication process. The benefits of hollow over solid microparticles were found to be higher encapsulation efficiency and a more rapid drug release rate. Further modification of the hollow microparticles was accomplished through the introduction of methyl-β-cyclodextrin. With this, a higher encapsulation efficiency of both drugs and an enhanced cumulative release were achieved. Spheroid study further demonstrated that the controlled release of the drugs from the methyl-β-cyclodextrin -loaded hollow microparticles exhibited enhanced tumor regressions of MCF-7 tumor spheroids. Such hollow dual-drug-loaded hollow microparticles with sustained releasing capabilities may have a potential for future applications in cancer therapy.

Modeling of plasticity and fracture of metals at shock loading

NASA Astrophysics Data System (ADS)

Mayer, A. E.; Khishchenko, K. V.; Levashov, P. R.; Mayer, P. N.

2013-05-01

In this paper, we present a model of dislocation plasticity and fracture of metals, which in combination with the wide-range equation of state and the continuum mechanics equations is a necessary component for simulation of the shock-wave loading. We take into account immobilization of dislocations and nucleation of micro-voids in weakened zones of substance; this is distinguished feature of the present version of the model. Accounting of the dislocations immobilization provides a better description of the unloading wave structure, while the detailed consideration of processes in the weakened zones expands the domain of applicability of fracture model to higher strain rates. We compare our results with the experimental data for the shock loading of aluminum, copper, and nickel samples; the comparison indicates satisfactory description of the elastic precursor, unloading wave, and spall pulse. Using the model, we investigate intently the early stage of the shock formation in solids; it is found out that the elastic precursor is formed even for a strong shock wave, and initially the precursor has very large amplitude and propagation velocity.

ZIP3D: An elastic and elastic-plastic finite-element analysis program for cracked bodies

NASA Technical Reports Server (NTRS)

Shivakumar, K. N.; Newman, J. C., Jr.

1990-01-01

ZIP3D is an elastic and an elastic-plastic finite element program to analyze cracks in three dimensional solids. The program may also be used to analyze uncracked bodies or multi-body problems involving contacting surfaces. For crack problems, the program has several unique features including the calculation of mixed-mode strain energy release rates using the three dimensional virtual crack closure technique, the calculation of the J integral using the equivalent domain integral method, the capability to extend the crack front under monotonic or cyclic loading, and the capability to close or open the crack surfaces during cyclic loading. The theories behind the various aspects of the program are explained briefly. Line-by-line data preparation is presented. Input data and results for an elastic analysis of a surface crack in a plate and for an elastic-plastic analysis of a single-edge-crack-tension specimen are also presented.

Tribological Behavior of IN718 Superalloy Coating Fabricated by Laser Additive Manufacturing

NASA Astrophysics Data System (ADS)

Zhang, Yaocheng; Pan, Qiyong; Yang, Li; Li, Ruifeng; Dai, Jun

2017-12-01

The tribological behavior of laser manufactured IN718 superalloy coating are investigated with different applied loads, sliding speeds and lubricating mediums. The wear resistance of laser manufactured IN718 coating is increased by heat treatment due to higher microhardness and homogeneous brittle phase distribution. The principal factors for the wear rate are applied load and lubricating medium. The worn surface of laser manufactured IN718 coating consists of the grooves, crack, wear debris and material delamination generated by the fatigue wear associated with adhesive wear and abrasive wear. The friction coefficients are influenced by the tribological noise decrescence by the tribo-oxidant and the liquid lubricant. The real contact temperature between coating sample and frictional counterpart is higher than the solid-solution temperature of IN718 superalloy, and the effect of surface contact temperature on the orientational microstructure and wear resistance for dry friction and wet friction process is indistinct.

A sublimation heat engine

PubMed Central

Wells, Gary G.; Ledesma-Aguilar, Rodrigo; McHale, Glen; Sefiane, Khellil

2015-01-01

Heat engines are based on the physical realization of a thermodynamic cycle, most famously the liquid–vapour Rankine cycle used for steam engines. Here we present a sublimation heat engine, which can convert temperature differences into mechanical work via the Leidenfrost effect. Through controlled experiments, quantified by a hydrodynamic model, we show that levitating dry-ice blocks rotate on hot turbine-like surfaces at a rate controlled by the turbine geometry, temperature difference and solid material properties. The rotational motion of the dry-ice loads is converted into electric power by coupling to a magnetic coil system. We extend our concept to liquid loads, generalizing the realization of the new engine to both sublimation and the instantaneous vapourization of liquids. Our results support the feasibility of low-friction in situ energy harvesting from both liquids and ices. Our concept is potentially relevant in challenging situations such as deep drilling, outer space exploration or micro-mechanical manipulation. PMID:25731669

A sublimation heat engine.

PubMed

Wells, Gary G; Ledesma-Aguilar, Rodrigo; McHale, Glen; Sefiane, Khellil

2015-03-03

Heat engines are based on the physical realization of a thermodynamic cycle, most famously the liquid-vapour Rankine cycle used for steam engines. Here we present a sublimation heat engine, which can convert temperature differences into mechanical work via the Leidenfrost effect. Through controlled experiments, quantified by a hydrodynamic model, we show that levitating dry-ice blocks rotate on hot turbine-like surfaces at a rate controlled by the turbine geometry, temperature difference and solid material properties. The rotational motion of the dry-ice loads is converted into electric power by coupling to a magnetic coil system. We extend our concept to liquid loads, generalizing the realization of the new engine to both sublimation and the instantaneous vapourization of liquids. Our results support the feasibility of low-friction in situ energy harvesting from both liquids and ices. Our concept is potentially relevant in challenging situations such as deep drilling, outer space exploration or micro-mechanical manipulation.

Automatic remote-integration metering center. Final report

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

Philippidis, P.A.; Weinreb, M.; de Gil, B.F.

1988-11-01

The report documents a multi-phase program for the development and demonstration of a unique automatic and remote metering system. The system consists of a solid-state meter module to provide electrical consumption data, tamper detection, and load control functions; a central master station to interrogate the meter modules for their data and also to transmit load control signals; and a data display module to be accessible to tenants wishing to obtain their meter readings. The system has the capability to measure and allocate demand and to process time of use rates. It also has a meter accuracy self-test feature. The systemmore » is suitable for both direct metering of multi-family buildings and the sub-metering of master-metered apartment buildings. In addition to describing the system, the report documents the results of a 371-point field trial at Scott Tower, a cooperative apartment building in the Bronx, New York.« less

The viscoelastic standard nonlinear solid model: predicting the response of the lumbar intervertebral disk to low-frequency vibrations.

PubMed

Groth, Kevin M; Granata, Kevin P

2008-06-01

Due to the mathematical complexity of current musculoskeletal spine models, there is a need for computationally efficient models of the intervertebral disk (IVD). The aim of this study is to develop a mathematical model that will adequately describe the motion of the IVD under axial cyclic loading as well as maintain computational efficiency for use in future musculoskeletal spine models. Several studies have successfully modeled the creep characteristics of the IVD using the three-parameter viscoelastic standard linear solid (SLS) model. However, when the SLS model is subjected to cyclic loading, it underestimates the load relaxation, the cyclic modulus, and the hysteresis of the human lumbar IVD. A viscoelastic standard nonlinear solid (SNS) model was used to predict the response of the human lumbar IVD subjected to low-frequency vibration. Nonlinear behavior of the SNS model was simulated by a strain-dependent elastic modulus on the SLS model. Parameters of the SNS model were estimated from experimental load deformation and stress-relaxation curves obtained from the literature. The SNS model was able to predict the cyclic modulus of the IVD at frequencies of 0.01 Hz, 0.1 Hz, and 1 Hz. Furthermore, the SNS model was able to quantitatively predict the load relaxation at a frequency of 0.01 Hz. However, model performance was unsatisfactory when predicting load relaxation and hysteresis at higher frequencies (0.1 Hz and 1 Hz). The SLS model of the lumbar IVD may require strain-dependent elastic and viscous behavior to represent the dynamic response to compressive strain.

Space shuttle solid rocket booster recovery system definition. Volume 3: SRB water impact loads computer program, user's manual

NASA Technical Reports Server (NTRS)

1973-01-01

This user's manual describes the FORTRAN IV computer program developed to compute the total vertical load, normal concentrated pressure loads, and the center of pressure of typical SRB water impact slapdown pressure distributions specified in the baseline configuration. The program prepares the concentrated pressure load information in punched card format suitable for input to the STAGS computer program. In addition, the program prepares for STAGS input the inertia reacting loads to the slapdown pressure distributions.

Silver doped catalysts for treatment of exhaust

DOEpatents

Park, Paul Worn [Peoria, IL; Boyer, Carrie L [Shiloh, IL

2006-12-26

A method of making an exhaust treatment catalyst includes dispersing a metal-based material in a first solvent to form a first slurry and allowing polymerization of the first slurry to occur. Polymerization of the first slurry may be quenched and the first slurry may be allowed to harden into a solid. This solid may be redistributed in a second solvent to form a second slurry. The second slurry may be loaded with a silver-based material, and a silver-loaded powder may be formed from the second slurry.

The evaluation of physical properties of injection molded systems based on poly(ethylene oxide) (PEO).

PubMed

Pajander, Jari; Rensonnet, Alexia; Hietala, Sami; Rantanen, Jukka; Baldursdottir, Stefania

2017-02-25

The effect of product design parameters on the formation and properties of an injection molded solid dosage form consisting of poly(ethylene oxide)s (PEO) and two different active pharmaceutical ingredients (APIs) was studied. The product design parameters explored were melting temperature and the duration of melting, API loading degree and the molecular weight (M w ) of PEO. The solid form composition of the model APIs, theophylline and carbamazepine, was of specific interest, and its possible impact on the in vitro drug release behavior. M w of PEO had the greatest impact on the release rate of both APIs. High M w resulted in slower API release rate. Process temperature had two-fold effect with PEO 300,000g/mol. Firstly, higher process temperature transformed the crystalline part of the polymer into metastable folded form (more folded crystalline regions) and less into the more stable extended form (more extended crystalline regions), which lead to enhanced theophylline release rate. Secondly, the higher process temperature seemed to induce carbamazepine polymorphic transformation from p-monoclinic form III (carbamazepine (M)) into trigonal form II (carbamazepine (T)). The results indicated that the actual content of carbamazepine (T) affected drug release behavior more than the magnitude of transformation. Copyright © 2016 Elsevier B.V. All rights reserved.

Removal of Suspended Solids in Anaerobically Digested Slurries of Livestock and Poultry Manure by Coagulation Using Different Dosages of Polyaluminum Chloride

NASA Astrophysics Data System (ADS)

Li, P.; Zhang, C. J.; Zhao, T. K.; Zhong, H.

2017-01-01

In this study, anaerobically digested slurries of livestock and poultry manure were pretreated by coagulation-sedimentation using an inorganic polymer coagulant, polyaluminum chloride (PAC). The effect of different PAC dosages on suspended solids (SS) removal and pH in the biogas slurries was assessed to provide reference values for reducing the organic load of biogas slurry in the coagulation-sedimentation process and explore the feasibility of reducing the difficulty in subsequent utilization or processing of biogas slurry. The results showed that for the pig slurry containing approximately 5000 mg/L SS, the removal rate of SS reached up to 81.6% with the coagulant dosage of 0.28 g/L PAC. For the chicken slurry containing approximately 2600 mg/L SS, the removal rate of SS was 30.2% with the coagulant dosage of 0.33 g/L PAC. The removal rate of SS in both slurries of livestock and poultry manure exhibited a downward trend with high PAC dosage. Therefore, there is a need to control the PAC dosage in practical use. The pH changed little in the two types of biogas slurries after treatment with different PAC dosages and both were in line with the standard values specified in the “Standards for Irrigation Water Quality”.

Impact of saccharides on the drying kinetics of agarose gels measured by in-situ interferometry

NASA Astrophysics Data System (ADS)

Mao, Bosi; Divoux, Thibaut; Snabre, Patrick

2017-01-01

Agarose gels are viscoelastic soft solids that display a porous microstructure filled with water at 90% w/w or more. Despite an extensive use in food industry and microbiology, little is known about the drying kinetics of such squishy solids, which suffers from a lack of time-resolved local measurements. Moreover, only scattered empirical observations are available on the role of the gel composition on the drying kinetics. Here we study by in-situ interferometry the drying of agarose gels of various compositions cast in Petri dishes. The gel thinning is associated with the displacement of interference fringes that are analyzed using an efficient spatiotemporal filtering method, which allows us to assess local thinning rates as low as 10 nm/s with high accuracy. The gel thinning rate measured at the center of the dish appears as a robust observable to quantify the role of additives on the gel drying kinetics and compare the drying speed of agarose gels loaded with various non-gelling saccharides of increasing molecular weights. Our work shows that saccharides systematically decrease the agarose gel thinning rate up to a factor two, and exemplifies interferometry as a powerful tool to quantify the impact of additives on the drying kinetics of polymer gels.

Characterization of surface-water quality based on real-time monitoring and regression analysis, Quivira National Wildlife Refuge, south-central Kansas, December 1998 through June 2001

USGS Publications Warehouse

Christensen, V.G.

2001-01-01

Because of the considerable wildlife benefits offered by the Quivira National Wildlife Refuge in south-central Kansas, there is a desire to ensure suitable water quality. To assess the quality of water flowing from Rattlesnake Creek into the refuge, the U.S. Geological Survey collected periodic water samples from December 1998 through June 2001 and analyzed the samples for physical properties, dissolved solids, total suspended solids, suspended sediment, major ions, nutrients, metals, pesticides, and indicator bacteria. Concentrations of 10 of the 125 chemicals analyzed did not meet water-quality criteria to protect aquatic life and drinking water in a least one sample. These were pH, turbidity, dissolved oxygen, dissolved solids, sodium, chloride, phosphorus, total coliform bacteria, E. coli bacteria, and fecal coliform bacteria. No metal or pesticide concentrations exceeded water-quality criteria. Twenty-two of the 43 metals analyzed were not detected, and 36 of the 46 pesticides analyzed were not detected. Because dissolved solids, sodium, chloride, fecal coliform bacteria, and other chemicals that are a concern for the health and habitat of fish and wildlife at the refuge cannot be measured continuously, regression equations were developed from a comparison of the analytical results of periodic samples and in-stream monitor measurements of specific conductance, pH, water temperature, turbidity, and dissolved oxygen. A continuous record of estimated chemical concentrations was developed from continuously recorded in-stream measurements. Annual variation in water quality was evaluated by comparing 1999 and 2000 sample data- the 2 years for which complete data sets were available. Median concentrations of alkalinity, fluoride, nitrate, and fecal coliform bacteria were smaller or did not change from 1999 to 2000. Dissolved solids, total suspended solids, sodium, chloride, sulfate, total organic nitrogen, and total phosphorus had increases in median concentrations from 1999 to 2000. Increases in the median concentrations of the major ions were expected due to decreased rainfall in 2000 and very low streamflow late in the year. Increases for solids and nutrients may have been due to the unusually high streamflow in the early spring of 2000. This was the time of year when fields were tilled, exposing solids and nutrients that were transported with runoff to Rattlesnake Creek. Load estimates indicate the chemical mass transported into the refuge and can be used in the development of total maximum daily loads (as specified by the U.S. Environmental Protection Agency) for water-quality contaminants in Rattlesnake Creek. Load estimates also were used to evaluate seasonal variation in water quality. Seasonal variation was most pronounced in the estimates of nutrient loads, and most of the nutrient load transported to the refuge occurred during just a few periods of surface runoff in the spring and summer. This information may be used by resource managers to determine when water-diversion strategies would be most beneficial. Load estimates also were used to calculate yields, which are useful for site comparisons. The continuous and real-time nature of the record of estimated concentrations, loads, and yields may be important for resource managers, recreationalists, or others for evaluating water-diversion strategies, making water-use decisions, or assessing the environmental effects of chemicals in time to prevent adverse effects on fish or other aquatic life at the refuge.

Water-quality characteristics, including sodium-adsorption ratios, for four sites in the Powder River drainage basin, Wyoming and Montana, water years 2001-2004

USGS Publications Warehouse

Clark, Melanie L.; Mason, Jon P.

2006-01-01

The U.S. Geological Survey, in cooperation with the Wyoming Department of Environmental Quality, monitors streams throughout the Powder River structural basin in Wyoming and parts of Montana for potential effects of coalbed natural gas development. Specific conductance and sodium-adsorption ratios may be larger in coalbed waters than in stream waters that may receive the discharge waters. Therefore, continuous water-quality instruments for specific conductance were installed and discrete water-quality samples were collected to characterize water quality during water years 2001-2004 at four sites in the Powder River drainage basin: Powder River at Sussex, Wyoming; Crazy Woman Creek near Arvada, Wyoming; Clear Creek near Arvada, Wyoming; and Powder River at Moorhead, Montana. During water years 2001-2004, the median specific conductance of 2,270 microsiemens per centimeter at 25 degrees Celsius (?S/cm) in discrete samples from the Powder River at Sussex, Wyoming, was larger than the median specific conductance of 1,930 ?S/cm in discrete samples collected downstream from the Powder River at Moorhead, Montana. The median specific conductance was smallest in discrete samples from Clear Creek (1,180 ?S/cm), which has a dilution effect on the specific conductance for the Powder River at Moorhead, Montana. The daily mean specific conductance from continuous water-quality instruments during the irrigation season showed the same spatial pattern as specific conductance values for the discrete samples. Dissolved sodium, sodium-adsorption ratios, and dissolved solids generally showed the same spatial pattern as specific conductance. The largest median sodium concentration (274 milligrams per liter) and the largest range of sodium-adsorption ratios (3.7 to 21) were measured in discrete samples from the Powder River at Sussex, Wyoming. Median concentrations of sodium and sodium-adsorption ratios were substantially smaller in Crazy Woman Creek and Clear Creek, which tend to decrease sodium concentrations and sodium-adsorption ratios at the Powder River at Moorhead, Montana. Dissolved-solids concentrations in discrete samples were closely correlated with specific conductance values; Pearson's correlation coefficients were 0.98 or greater for all four sites. Regression equations for discrete values of specific conductance and sodium-adsorption ratios were statistically significant (p-values <0.001) at all four sites. The strongest relation (R2=0.92) was at the Powder River at Sussex, Wyoming. Relations on Crazy Woman Creek (R2=0.91) and Clear Creek (R2=0.83) also were strong. The relation between specific conductance and sodium-adsorption ratios was weakest (R2=0.65) at the Powder River at Moorhead, Montana; however, the relation was still significant. These data indicate that values of specific conductance are useful for estimating sodium-adsorption ratios. A regression model called LOADEST was used to estimate dissolved-solids loads for the four sites. The average daily mean dissolved-solids loads varied among the sites during water year 2004. The largest average daily mean dissolved-solids load was calculated for the Powder River at Moorhead, Montana. Although the smallest concentrations of dissolved solids were in samples from Clear Creek, the smallest average daily mean dissolved-solids load was calculated for Crazy Woman Creek. The largest loads occurred during spring runoff, and the smallest loads occurred in late summer, when streamflows typically were smallest. Dissolved-solids loads may be smaller than average during water years 2001-2004 because of smaller than average streamflow as a result of drought conditions.

Verification of Texas superheavy load criteria for bridges.

DOT National Transportation Integrated Search

2011-11-01

This report evaluates TxDOT criteria for the superheavy loads that trigger bridge analyses to determine : whether the criteria adequately protects Texas bridges. Researchers used solid modeling calibrated with a : bridge test of a 3-span continuous s...

Silymarin-loaded solid nanoparticles provide excellent hepatic protection: physicochemical characterization and in vivo evaluation

PubMed Central

Yang, Kwan Yeol; Hwang, Du Hyeong; Yousaf, Abid Mehmood; Kim, Dong Wuk; Shin, Young-Jun; Bae, Ok-Nam; Kim, Yong-II; Kim, Jong Oh; Yong, Chul Soon; Choi, Han-Gon

2013-01-01

Background The purpose of this study was to develop a novel silymarin-loaded solid nanoparticle system with enhanced oral bioavailability and an ability to provide excellent hepatic protection for poorly water-soluble drugs using Shirasu porous glass (SPG) membrane emulsification and a spray-drying technique. Methods A silymarin-loaded liquid nanoemulsion was formulated by applying the SPG membrane emulsification technique. This was further converted into solid state nanosized particles by the spray-drying technique. The physicochemical characteristics of these nanoparticles were determined by scanning electron microscopy, differential scanning calorimetry, and powder X-ray diffraction. Their dissolution, bioavailability, and hepatoprotective activity in rats were assessed by comparison with a commercially available silymarin-loaded product. Results Formulation of a silymarin-loaded nanoemulsion, comprising silymarin, castor oil, polyvinylpyrrolidone, Transcutol HP, Tween 80, and water at a weight ratio of 5/3/3/1.25/1.25/100 was accomplished using an SPG membrane emulsification technique at an agitator speed of 700 rpm, a feed pressure of 15 kPa, and a continuous phase temperature of 25°C. This resulted in generation of comparatively uniform emulsion globules with a narrow size distribution. Moreover, the silymarin-loaded solid nanoparticles, containing silymarin/castor oil/polyvinylpyrrolidone/Transcutol HP/Tween 80 at a weight ratio of 5/3/3/1.25/1.25, improved about 1,300-fold drug solubility and retained a mean size of about 210 nm. Silymarin was located in unaltered crystalline form in the nanoparticles. The drug dissolved rapidly from the nanoparticles, reaching nearly 80% within 15 minutes, indicating three-fold better dissolution than that of the commercial product. Further, the nanoparticles showed a considerably shorter time to peak concentration, a greater area under the concentration-time curve, and a higher maximum concentration of silymarin compared with the commercial product (P < 0.05). In particular, the area under the concentration-time curve of the drug provided by the nanoparticles was approximately 1.3-fold greater than that of the commercial product. In addition, the silymarin-loaded nanoparticles significantly reduced carbon tetrachloride-induced hepatotoxicity, indicating improved bioactivity compared with silymarin powder and the commercial product. Conclusion Silymarin-loaded nanoparticles developed using SPG membrane emulsification and spray-drying techniques could be a useful system for delivery of poorly water-soluble silymarin while affording excellent hepatic protection. PMID:24039417

Synthesis of protein-coated biocompatible methotrexate-loaded PLA-PEG-PLA nanoparticles for breast cancer treatment

PubMed Central

Massadeh, Salam; Alaamery, Manal; Al-Qatanani, Shatha; Alarifi, Saqer; Bawazeer, Shahad; Alyafee, Yusra

2016-01-01

Background PLA-PEG-PLA triblock polymer nanoparticles are promising tools for targeted dug delivery. The main aim in designing polymeric nanoparticles for drug delivery is achieving a controlled and targeted release of a specific drug at the therapeutically optimal rate and choosing a suitable preparation method to encapsulate the drug efficiently, which depends mainly on the nature of the drug (hydrophilic or hydrophobic). In this study, methotrexate (MTX)-loaded nanoparticles were prepared by the double emulsion method. Method Biodegradable polymer polyethylene glycol-polylactide acid tri-block was used with poly(vinyl alcohol) as emulsifier. The resulting methotrexate polymer nanoparticles were coated with bovine serum albumin in order to improve their biocompatibility. This study focused on particle size distribution, zeta potential, encapsulation efficiency, loading capacity, and in vitro drug release at various concentrations of PVA (0.5%, 1%, 2%, and 3%). Results Reduced particle size of methotrexate-loaded nanoparticles was obtained using lower PVA concentrations. Enhanced encapsulation efficiency and loading capacity was obtained using 1% PVA. FT-IR characterization was conducted for the void polymer nanoparticles and for drug-loaded nanoparticles with methotrexate, and the protein-coated nanoparticles in solid state showed the structure of the plain PEG-PLA and the drug-loaded nanoparticles with methotrexate. The methotrexate-loaded PLA-PEG-PLA nanoparticles have been studied in vitro; the drug release, drug loading, and yield are reported. Conclusion The drug release profile was monitored over a period of 168 hours, and was free of burst effect before the protein coating. The results obtained from this work are promising; this work can be taken further to develop MTX based therapies.

Sensitivity kernels for viscoelastic loading based on adjoint methods

NASA Astrophysics Data System (ADS)

Al-Attar, David; Tromp, Jeroen

2014-01-01

Observations of glacial isostatic adjustment (GIA) allow for inferences to be made about mantle viscosity, ice sheet history and other related parameters. Typically, this inverse problem can be formulated as minimizing the misfit between the given observations and a corresponding set of synthetic data. When the number of parameters is large, solution of such optimization problems can be computationally challenging. A practical, albeit non-ideal, solution is to use gradient-based optimization. Although the gradient of the misfit required in such methods could be calculated approximately using finite differences, the necessary computation time grows linearly with the number of model parameters, and so this is often infeasible. A far better approach is to apply the `adjoint method', which allows the exact gradient to be calculated from a single solution of the forward problem, along with one solution of the associated adjoint problem. As a first step towards applying the adjoint method to the GIA inverse problem, we consider its application to a simpler viscoelastic loading problem in which gravitationally self-consistent ocean loading is neglected. The earth model considered is non-rotating, self-gravitating, compressible, hydrostatically pre-stressed, laterally heterogeneous and possesses a Maxwell solid rheology. We determine adjoint equations and Fréchet kernels for this problem based on a Lagrange multiplier method. Given an objective functional J defined in terms of the surface deformation fields, we show that its first-order perturbation can be written δ J = int _{MS}K_{η }δ ln η dV +int _{t0}^{t1}int _{partial M}K_{dot{σ }} δ dot{σ } dS dt, where δ ln η = δη/η denotes relative viscosity variations in solid regions MS, dV is the volume element, δ dot{σ } is the perturbation to the time derivative of the surface load which is defined on the earth model's surface ∂M and for times [t0, t1] and dS is the surface element on ∂M. The `viscosity kernel' Kη determines the linearized sensitivity of J to viscosity perturbations defined with respect to a laterally heterogeneous reference earth model, while the `rate-of-loading kernel' K_{dot{σ }} determines the sensitivity to variations in the time derivative of the surface load. By restricting attention to spherically symmetric viscosity perturbations, we also obtain a `radial viscosity kernel' overline{K}_{η } such that the associated contribution to δJ can be written int _{IS}overline{K}_{η }δ ln η dr, where IS denotes the subset of radii lying in solid regions. In order to illustrate this theory, we describe its numerical implementation in the case of a spherically symmetric earth model using a 1-D spectral element method, and calculate sensitivity kernels for a range of realistic observables.

Pilot-scale anaerobic co-digestion of municipal biomass waste and waste activated sludge in China: Effect of organic loading rate

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

Liu Xiao, E-mail: liuxiao07@mails.tsinghua.edu.cn; Wang Wei; Shi Yunchun

2012-11-15

Highlights: Black-Right-Pointing-Pointer Co-digestion of municipal biomass waste (MBW) and waste activated sludge (WAS) was examined on a pilot-scale reactor. Black-Right-Pointing-Pointer System performance and stability under OLR of 1.2, 2.4, 3.6, 4.8, 6.0 and 8.0 kg VS (m{sup 3} d){sup -1} were analyzed. Black-Right-Pointing-Pointer A maximum methane production rate of 2.94 m{sup 3} (m{sup 3} d){sup -1} was achieved at OLR of 8.0 kg VS (m{sup 3} d){sup -1} and HRT of 15d. Black-Right-Pointing-Pointer With the increasing OLRs, pH values, VS removal rate and methane concentration decreased and VFA increased. Black-Right-Pointing-Pointer The changing of biogas production rate can be a practicalmore » approach to monitor and control anaerobic digestion system. - Abstract: The effects of organic loading rate on the performance and stability of anaerobic co-digestion of municipal biomass waste (MBW) and waste activated sludge (WAS) were investigated on a pilot-scale reactor. The results showed that stable operation was achieved with organic loading rates (OLR) of 1.2-8.0 kg volatile solid (VS) (m{sup 3} d){sup -1}, with VS reduction rates of 61.7-69.9%, and volumetric biogas production of 0.89-5.28 m{sup 3} (m{sup 3} d){sup -1}. A maximum methane production rate of 2.94 m{sup 3} (m{sup 3} d){sup -1} was achieved at OLR of 8.0 kg VS (m{sup 3} d){sup -1} and hydraulic retention time of 15 days. With increasing OLRs, the anaerobic reactor showed a decrease in VS removal rate, average pH value and methane concentration, and a increase of volatile fatty acid concentration. By monitoring the biogas production rate (BPR), the anaerobic digestion system has a higher acidification risk under an OLR of 8.0 kg VS (m{sup 3} d){sup -1}. This result remarks the possibility of relating bioreactor performance with BPR in order to better understand and monitor anaerobic digestion process.« less

Continuous water-quality monitoring and regression analysis to estimate constituent concentrations and loads in the Red River of the North, Fargo, North Dakota, 2003-05

USGS Publications Warehouse

Ryberg, Karen R.

2006-01-01

This report presents the results of a study by the U.S. Geological Survey, done in cooperation with the Bureau of Reclamation, U.S. Department of the Interior, to estimate water-quality constituent concentrations in the Red River of the North at Fargo, North Dakota. Regression analysis of water-quality data collected in 2003-05 was used to estimate concentrations and loads for alkalinity, dissolved solids, sulfate, chloride, total nitrite plus nitrate, total nitrogen, total phosphorus, and suspended sediment. The explanatory variables examined for regression relation were continuously monitored physical properties of water-streamflow, specific conductance, pH, water temperature, turbidity, and dissolved oxygen. For the conditions observed in 2003-05, streamflow was a significant explanatory variable for all estimated constituents except dissolved solids. pH, water temperature, and dissolved oxygen were not statistically significant explanatory variables for any of the constituents in this study. Specific conductance was a significant explanatory variable for alkalinity, dissolved solids, sulfate, and chloride. Turbidity was a significant explanatory variable for total phosphorus and suspended sediment. For the nutrients, total nitrite plus nitrate, total nitrogen, and total phosphorus, cosine and sine functions of time also were used to explain the seasonality in constituent concentrations. The regression equations were evaluated using common measures of variability, including R2, or the proportion of variability in the estimated constituent explained by the regression equation. R2 values ranged from 0.703 for total nitrogen concentration to 0.990 for dissolved-solids concentration. The regression equations also were evaluated by calculating the median relative percentage difference (RPD) between measured constituent concentration and the constituent concentration estimated by the regression equations. Median RPDs ranged from 1.1 for dissolved solids to 35.2 for total nitrite plus nitrate. Regression equations also were used to estimate daily constituent loads. Load estimates can be used by water-quality managers for comparison of current water-quality conditions to water-quality standards expressed as total maximum daily loads (TMDLs). TMDLs are a measure of the maximum amount of chemical constituents that a water body can receive and still meet established water-quality standards. The peak loads generally occurred in June and July when streamflow also peaked.

Design and Certification of the Extravehicular Activity Mobility Unit (EMU) Water Processing Jumper

NASA Technical Reports Server (NTRS)

Peterson, Laurie J.; Neumeyer, Derek J.; Lewis, John F.

2006-01-01

The Extravehicular Mobility Units (EMUs) onboard the International Space Station (ISS) experienced a failure due to cooling water contamination from biomass and corrosion byproducts forming solids around the EMU pump rotor. The coolant had no biocide and a low pH which induced biofilm growth and corrosion precipitates, respectively. NASA JSC was tasked with building hardware to clean the ionic, organic, and particulate load from the EMU coolant loop before and after Extravehicular Activity (EVAs). Based on a return sample of the EMU coolant loop, the chemical load was well understood, but there was not sufficient volume of the returned sample to analyze particulates. Through work with EMU specialists, chemists, (EVA) Mission Operations Directorate (MOD) representation, safety and mission assurance, astronaut crew, and team engineers, requirements were developed for the EMU Water Processing hardware (sometimes referred to as the Airlock Coolant Loop Recovery [A/L CLR] system). Those requirements ranged from the operable level of ionic, organic, and particulate load, interfaces to the EMU, maximum cycle time, operating pressure drop, flow rate, and temperature, leakage rates, and biocide levels for storage. Design work began in February 2005 and certification was completed in April 2005 to support a return to flight launch date of May 12, 2005. This paper will discuss the details of the design and certification of the EMU Water Processing hardware and its components

High-pressure phase transitions of α-quartz under nonhydrostatic dynamic conditions: A reconnaissance study at PETRA III

NASA Astrophysics Data System (ADS)

Carl, Eva-Regine; Mansfeld, Ulrich; Liermann, Hanns-Peter; Danilewsky, Andreas; Langenhorst, Falko; Ehm, Lars; Trullenque, Ghislain; Kenkmann, Thomas

2017-07-01

Hypervelocity collisions of solid bodies occur frequently in the solar system and affect rocks by shock waves and dynamic loading. A range of shock metamorphic effects and high-pressure polymorphs in rock-forming minerals are known from meteorites and terrestrial impact craters. Here, we investigate the formation of high-pressure polymorphs of α-quartz under dynamic and nonhydrostatic conditions and compare these disequilibrium states with those predicted by phase diagrams derived from static experiments under equilibrium conditions. We create highly dynamic conditions utilizing a mDAC and study the phase transformations in α-quartz in situ by synchrotron powder X-ray diffraction. Phase transitions of α-quartz are studied at pressures up to 66.1 and different loading rates. At compression rates between 0.14 and 1.96 GPa s-1, experiments reveal that α-quartz is amorphized and partially converted to stishovite between 20.7 GPa and 28.0 GPa. Therefore, coesite is not formed as would be expected from equilibrium conditions. With the increasing compression rate, a slight increase in the transition pressure occurs. The experiments show that dynamic compression causes an instantaneous formation of structures consisting only of SiO6 octahedra rather than the rearrangement of the SiO4 tetrahedra to form a coesite. Although shock compression rates are orders of magnitude faster, a similar mechanism could operate in impact events.