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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Improved consolidation of silicon carbide

Alpha silicon carbide powder was consolidated by both dry and wet methods. Dry pressing in a double acting steel die yielded sintered test bars with an average flexural strength of 235.6 MPa with a critical flaw size of approximately 100 micro m. An aqueous slurry pressing technique produced sintered test bars with an average flexural strength of 440.8 MPa with a critical flaw size of approximately 25 micro m. Image analysis revealed a reduction in both pore area and pore size distribution in the slurry pressed sintered test bars. The improvements in the slurry pressed material properties are discussed in terms of reduced agglomeration and improved particle packing during consolidation.

Freedman, M. R.↗
NASA NTRS1986

Improved consolidation of silicon carbide

Alpha silicon carbide powder was consolidated by both dry and wet methods. Dry pressing in a double acting steel die yielded sintered test bars with an average flexural strength of 235.6 MPa with a critical flaw size of approximately 100 micro m. An aqueous slurry pressing technique produced sintered test bars with an average flexural strength of 440.8 MPa with a critical flaw size of approximately 25 micro m. Image analysis revealed a reduction in both pore area and pore size distribution in the slurry pressed sintered test bars. The improvements in the slurry pressed material properties are discussed in terms of reduced agglomeration and improved particle packing during consolidation.

Freedman, M. R.↗
NASA NTRS2003

The effect of drying and size reduction pretreatments on recovery of inorganic crop nutrients from inedible wheat residues

Inorganic nutrients can be easily recovered from ALS crop residue solid wastes by aqueous leaching. However, oven drying and milling pretreatment of these residues has been frequently required to accommodate crop scientists and facility storage limitations. As part of a research study that will compare three different bioreactor technologies for processing these wastes, we realized that different drying and size-reduction pretreatments had been utilized for each technology. This paper compares the effects of residue pretreatment on recovery of nutrients by leaching. Pretreatments included three drying methods [fresh, oven-dried (70 degrees C overnight), and freeze-dried] and two size reduction methods [chopped (2 cm length) and milled (2 mm diameter)]. Determination of mass balances (dry weight and ash content of solids) before and after leaching indicated solubilization was least for fresh residues (23% dry weight loss and 50% for ash loss), and most for freeze-dried residues (41-47% dry weight loss and nearly 100% for ash loss). Mineral recovery of major elements (NO3, PO4, K, Ca, and Mg) in leachates was poorest for fresh residues. P and K recovery in leachates were best for oven-dried residues and Ca, Mg, and N recovery best for freeze-dried residues. The differences in recovery for N, P, and K in leachates were minimal between chopping and milling and slightly better for Ca and Mg from milled residues.

NASA Center KSC↗
DOE OSTI2022

Dry Deposition Methods Based on Turbulence Kinetic Energy: 1. Evaluation of Various Resistances and Sensitivity Studies Using a Single‐Point Model

Different functions are used to account for turbulence strength in the atmospheric boundary layer for different stability regimes. These functions are one of the sources for differences among different atmospheric models' predictions and associated biases. Also, turbulence strength is underrepresented in some of the resistance formulations. Here, to address these issues with dry deposition, firstly we take advantage of three‐dimensional (3‐D) turbulence information in estimating resistances by proposing and validating a 3‐D turbulence velocity scale that is relevant for different stability regimes of boundary layer. Secondly, we hypothesize and validate that friction velocity measured by 3‐D sonic anemometer can be effectively replaced by the new turbulence velocity scale multiplied by the von Karman constant. Finally, we (a) present a set of resistance formulations for ozone (O 3 ) based on the 3‐D turbulence velocity scale; (b) intercompare estimations of such resistances with those obtained using existing formulations; and, (c) evaluate simulated O 3 fluxes using a single‐point dry deposition model against long‐term observations of O 3 fluxes at the Harvard Forest (MA) site. Results indicate that the new resistance formulations work very well in simulating surface latent heat and O 3 fluxes when compared to respective existing formulations and measurements at a decadal time scale. Findings from this research may help to improve the capability of dry deposition schemes for better estimation of dry deposition fluxes and create opportunities for the development of a community dry deposition model for use in regional/global air quality models.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2017

Construction of ultrathin N-doped carbon shell on LiFePO{sub 4} spheres as enhanced cathode for lithium ion batteries

Graphical abstract: N-doped carbon (N-C) coated LiFePO{sub 4} spheres have been prepared by a facile one-step spray drying method and demonstrated with high capacity and good cycling life as cathode of lithium ion batteries. - Highlights: • Construct N-C shell on LiFePO{sub 4} as enhanced cathode for LIBs. • LiFePO{sub 4}/N-C cathodes show high capacity and good cycling life. • N-C shell structure is favorable for fast electron transfer. - Abstract: Developing advanced cathode is playing a crucial role in the advancement of lithium ion batteries (LIBs). In this work, we report a novel one-step spray drying method for fabrication of N-doped carbon (N-C) coated LiFePO{sub 4} spheres forming LiFePO{sub 4}/N-C spheres composite. Thin N-C layer of about 5 nm was coating on the surface of LiFePO{sub 4} spheres. The electrochemical properties of LiFePO{sub 4}/N-C spheres composite have been thoroughly studied as cathode of LIBs. The LiFePO{sub 4}/N-C spheres composite delivers discharge capacities of 160, 143 and 115 mAh g{sup −1} at 1 C, 5 C and 20 C, respectively, much better than unmodified LiFePO{sub 4} cathode. A high discharge capacity of 159 mAh g{sup −1} is preserved with 99% capacity retention after 1000 cycles at 1 C. The enhanced performance is due to the introduction of N-C shell with improved electrical conductivity and structural stability.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Oxide Growth and Validation for Aluminum Research Reactor Fuel - 19422

Aluminum fuel cladding will undergo general corrosion with resulting formation of adherent oxide films during in-reactor and post-discharge exposures under various water conditions and temperatures. These oxides include chemically-bound water that can pose challenges for extended dry storage. This paper describes laboratory experiments performed to produce hydroxide (oxide) films on aluminum 1100, 6061 and 5052 series alloy substrates immersed in water at controlled temperatures. The results are compared to the oxide film present on a spent fuel assembly irradiated in research reactor. This work is part of a broad investigation to address knowledge gaps and technical data needs for dry storage of aluminum-clad spent nuclear fuel (SNF). To adequately assess the risks posed by chemically-bound water on SNF in dry storage and strategies for removing chemically bound water, it is necessary to understand the expected composition and loading of oxide films on SNF of different service histories and to investigate the response of such oxides to irradiation and potential drying methods. These efforts require both the growth of films under controlled conditions and the production of non-radioactive surrogates for testing. The current work comprises experimental investigation of oxide growth via (1) laboratory experiments to produce hydroxide films on aluminum alloy substrates immersed in water at controlled temperatures and (2) characterization and comparison of laboratory-grown oxides to oxides on service-exposed aluminum alloys. The important factors affecting oxide growth and characteristics typical of oxide films formed by aqueous corrosion under conditions similar to in-reactor are reviewed. Aluminum oxide films were grown under a variety of controlled temperature conditions and durations to serve as surrogates for oxides found on aluminum-clad spent nuclear fuel due to aqueous corrosion. The chemically-bound water found in oxides formed by aqueous corrosion poses challenges for extended dry storage, requiring investigation of how the oxide loading and characteristics vary with exposure history and to provide the initial condition for investigation of drying methods. Characteristics including chemical composition, oxide morphology, and film thickness were measured to assess whether the surrogate films were representative of in-service-produced oxides on SNF. Tests were conducted in liquid water at atmospheric pressure in the temperature range 50-100 deg. C, with and without heat flux through the corroding surface, to replicate in-service conditions, and at 185 deg. C inside pressure vessels to replicate pre-filming procedures. Three different alloys commonly used in aluminum clad research reactor fuel were considered: Al-1100, Al-6061, and Al-5052. Specimens were characterized by weighing before and after exposure to measure oxide mass loading, X-ray diffraction to identify oxide composition, and scanning electron microscopy to examine the oxide morphology and film thickness. The oxide type and the morphological characteristics of the film on a fuel element from the Uruguay RU1 research reactor were determined and compared to the laboratory surrogates. The results show some differences compared to the 50 deg. C laboratory specimen that are rationalized with the service storage history of the element. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Graphene oxide foams and their excellent adsorption ability for acetone gas

Graphical abstract: - Highlights: • GO and RGO foams were prepared using a simple and green method, unidirectional freeze-drying. • The porous structure of the foams can be adjusted by changing GO concentrations. • GO and RGO foams show good adsorption efficiency for acetone gas. - Abstract: Graphene oxide (GO) and reduced graphene oxide (RGO) foams were prepared using a unidirectional freeze-drying method. These porous carbon materials were characterized by thermal gravimetric analysis, differential scanning calorimetry, X-ray photoelectron spectroscopy and scanning electron microscopy. The adsorption behavior of the two kinds of foams for acetone was studied. The result showed that the saturated adsorption efficiency of the GO foams was over 100%, and was higher than that of RGO foams and other carbon materials.

36 MATERIALS SCIENCE↗
NASA NTRS2010

New Dry Fractionation Methods

This slide presentation describes new fractionation methods that are used to create dust that is respirable for testing the effects of inhalation of lunar dust in preparation for future manned lunar exploration. Because lunar dust is a very limited commodity, a method that does not result in loss of the material had to be developed. The dust separation system that is described incorporates some traditional methods, while preventing the dust from being contaminated or changed in reactivity properties while also limiting losses.

McKay, David S.↗
DOE OSTI2017

Dry etch method for texturing silicon and device

A method for texturing silicon includes loading a silicon wafer into a vacuum chamber, heating the silicon wafer and thermal cracking a gas to generate cracked sulfur species. The silicon wafer is exposed to the cracked sulfur species for a time duration in accordance with a texture characteristic needed for a surface of the silicon wafer.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Advanced Drying Process for Lower Manufacturing Cost of Electrodes

For this Vehicle Technologies Incubator/Energy Storage R&D topic, Lambda Technologies teamed with Navitas Systems and proposed a new advanced drying process that promised a 5X reduction in electrode drying time and significant reduction in the cost of large format lithium batteries used in PEV's. The operating principle of the proposed process was to use penetrating radiant energy source Variable Frequency Microwaves (VFM), that are selectively absorbed by the polar water or solvent molecules instantly in the entire volume of the electrode. The solvent molecules are thus driven out of the electrode thickness making the process more efficient and much faster than convective drying method. To evaluate the Advanced Drying Process (ADP) a hybrid prototype system utilizing VFM and hot air flow was designed and fabricated. While VFM drives the solvent out of the electrode thickness, the hot air flow exhausts the solvent vapors out of the chamber. The drying results from this prototype were very encouraging. For water based anodes there is a 5X drying advantage (time & length of oven) in using ADP over standard drying system and for the NMP based cathodes the reduction in drying time has 3X benefit. For energy savings the power consumption measurements were performed to ADP prototype and compared with the convection standard drying oven. The data collected demonstrated over 40% saving in power consumption with ADP as compared to the convection drying systems. The energy savings are one of the operational cost benefits possible with ADP. To further speed up the drying process, the ADP prototype was explored as a booster module before the convection oven and for the electrode material being evaluated it was possible to increase the drying speed by a factor of 4, which could not be accomplished with the standard dryer without surface defects and cracks. The instantaneous penetration of microwave in the entire slurry thickness showed a major advantage in rapid drying of the electrode materials. For the existing electrode materials, the material analysis and cell characterization data from ADP dried electrodes showed equivalent (or slightly better) performance. However, for high loading and thicker electrode materials (for high energy densities) the ADP advantages are more prominent. There was less binder migration, the resistance was lower hence the current capacities and retention of the battery cells were higher. The success of the project has enabled credible communications with commercial end users as well as battery coating line integrators. Goal is to scale ADP up for high volume manufacturing of Li-ion battery electrodes. The implementation of ADP in high volume manufacturing will reduce a high cost production step to bring the overall price of Li-ion batteries down. This will ultimately have a positive impact on the public by making electric and hybrid vehicles more affordable.

25 ENERGY STORAGE↗
DOE OSTI2020

Impact of Drying on Meso- and Nanoscale Structures of Citrus Fiber: A Study by SFG, ATR-IR, XRD, and DLS

Citrus fibers are a sidestream of the pectin extraction process from citrus peel. This sidestream can be converted into a functional ingredient through a shear-induced homogenization process. One technical challenge with this material is that dehydration and subsequent rehydration result in reduction of viscosity compared to the original product. In this study, various drying methods were compared with never-dried fibers to investigate the structural changes underlying the viscosity loss. Infrared and X-ray diffraction analyses confirmed no changes in chemical composition and crystalline structure of citrus fibers. Here, the dynamic light scattering and sum frequency generation analyses of citrus fiber suspension showed that the rehydration process could not fully disperse aggregated fibers, which appears to be the main cause for the viscosity loss.

09 BIOMASS FUELS↗
DOE OSTI2023

Impact of fabrication methods on binder distribution and charge transport in composite cathodes of all-solid-state batteries

Abstract The manufacturing process of all-solid-state batteries necessitates the use of polymer binders. However, these binders, being ionic insulators by nature, can adversely affect charge transport within composite cathodes, thereby impacting the rate performance of the batteries. In this work, we aim to investigate the impact of fabrication methods, specifically the solvent-free dry process versus the slurry-cast wet process, on binder distribution and charge transport in composite cathodes of solid-state batteries. In the dry process, the binder forms a fibrous network, while the wet process results in binder coverage on the surface of cathode active materials. The difference in microstructure leads to a notable 20-fold increase in ionic conductivity in the dry-processed cathode. Consequently, the cells processed via the dry method exhibit higher capacity retention of 89% and 83% at C/3 and C/2 rates, respectively, in comparison to 68% and 58% for the wet-processed cells at the same rate. These findings provide valuable insights into the influence of fabrication methods on binder distribution and charge transport, contributing to a better understanding of the binder’s role in manufacturing of all-solid-state batteries.

Emley, Benjamin↗
DOE OSTI2014

Nanoparticle preparation of Mefenamic acid by electrospray drying

Nanoparticles preparation of Mefenamic acid (MA) by using an electrospray drying method was conducted in this study. Electrospray drying is a process that uses electrostatic force to disperse a conductive liquid stream into fine charged droplets through the coulomb fission of charges in the liquid and finally dry into fine particles. Electrospray drying modes operation usually in Taylor cone jet, and it was formed by controlling applied voltage and liquid flow rate. A conductive liquid (2.77–8.55μScm{sup −1}) which is MA solution was prepared by using acetone with concentration 0.041 and 0.055 M before pumping at a flow rate of 3–6ml/h. By applying the applied voltage at 1.3–1.5 kV, Taylor cone jet mode was formed prior to the electrospray. During electrospray drying process, solvent evaporation from the droplet was occurring that leads to coulomb disruption and may generate to nanoparticles. The dried nanoparticles were collected on a grounded substrate that was placed at varying distance from the electrospray. MA particle with size range of 100–400 nm were produced by electrospray drying process. Characterization of particles by using X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) show that particles formed into polymorph I.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2011

PCB-Caulk Replacement Project Johnson Space Center Houston, TX

Wet method reduced exposure by minimizing overall respirable particulate release. Dry method didn't introduce delays for primer/caulk application. Removed caulks came in many forms, from dry powdery to tarry sticky. Varying textures were not sampled or packaged differently. During the course of the project, EPA modified recommended practices to include full containment for exterior caulk removal. Changes are ongoing. Initial recommendations were directed to school buildings. EPA is researching risks due to caulk. Exposure guidance lacking except for 2 of 209 PCB congeners. Work was safely completed on schedule and under budget.

Young, William M.↗
DOE OSTI2017

Dry Storage of Encapsulated Defective Fuel Rods at Doel 1 and 2 in Belgium - 17581

The project of removing all fissile and non-fissile material out of the spent fuel ponds of Belgian Doel power plant is on-going and in that framework, a solution was needed for evacuating all used fuel elements from Doel 1 and 2 storage pool, including Defective Fuel Assemblies (DFA) and Defective Fuel Rods (DFR). Following the moving out of storage pool, all used fuel elements are intended to be loaded in dry storage casks, this used fuel management option being the one implemented today in Belgium while waiting for final management. Synatom, in charge of all fuel cycle related activities for the nuclear power plants of Belgium and Engie-Electrabel, the operator of both Belgium power plants (Doel and Tihange), had then to find an industrial solution for emptying Doel 1 and 2 used fuel pool and loading DFR in dry storage casks. After having thoroughly reviewed the possible options for implementing dry storage of DFR, Synatom selected AREVA technology. It consists in: - encapsulating each DFR by loading the fuel rod in a capsule, drying the fuel rod using a process which allows to physically verify with high accuracy the residual water content inside the DFR, and welding the capsule, - assembling the capsules in a capsule canister (a skeleton with external dimensions similar to fuel assembly's) and - transferring this capsule canister along with intact fuel assemblies in an associated dry transport and storage (dual purpose) cask, as already used for interim storage of used fuel at Doel site. The French as well as the Belgian competent authorities are parties to the licensing process project. The purpose of the paper is to present the on-going industrial project related to dry storage of dried and encapsulated DFR - along with intact used fuel in dual purpose casks - at Doel 1 and 2 in Belgium, its challenges and progress. The paper presents: - why the drying method, welded capsule and associated cask is the best available technology for dry storage of DFR; - a focus on fuel assembly repair operations (initial step before encapsulation) per-formed in 2015 which consisted in successful extraction of four DFR from their original fuel assembly, using proven and experienced methods and tools; - in conclusion, an update of Doel 1 and 2 DFR dry storage project: reaching of major qualifications and licensing milestones and overview of the project perspectives. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗