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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 1,153 records · Page 64
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Crystallization In High Level Waste (HLW) Glass Melters: Operational Experience From The Savannah River Site

processing strategy for the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The basis of this alternative approach is an empirical model predicting the crystal accumulation in the WTP glass discharge riser and melter bottom as a function of glass composition, time, and temperature. When coupled with an associated operating limit (e.g., the maximum tolerable thickness of an accumulated layer of crystals), this model could then be integrated into the process control algorithms to formulate crystal tolerant high level waste (HLW) glasses targeting higher waste loadings while still meeting process related limits and melter lifetime expectancies. This report provides a review of the scaled melter testing that was completed in support of the Defense Waste Processing Facility (DWPF) melter. Testing with scaled melters provided the data to define the DWPF operating limits to avoid bulk (volume) crystallization in the un-agitated DWPF melter and provided the data to distinguish between spinels generated by K-3 refractory corrosion versus spinels that precipitated from the HLW glass melt pool. This report includes a review of the crystallization observed with the scaled melters and the full scale DWPF melters (DWPF Melter 1 and DWPF Melter 2). Examples of actual DWPF melter attainment with Melter 2 are given. The intent is to provide an overview of lessons learned, including some example data, that can be used to advance the development and implementation of an empirical model and operating limit for crystal accumulation for WTP. Operation of the first and second (current) DWPF melters has demonstrated that the strategy of using a liquidus temperature predictive model combined with a 100 °C offset from the normal melter operating temperature of 1150 °C (i.e., the predicted liquidus temperature (TL) of the glass must be 1050 °C or less) has been successful in preventing any detrimental accumulation of spinel in the DWPF melt pool, and spinel has not been observed in any of the pour stream glass samples. Spinel was observed at the bottom of DWPF Melter 1 as a result of K-3 refractory corrosion. Issues have occurred with accumulation of spinel in the pour spout during periods of operation at higher waste loadings. Given that both DWPF melters were or have been in operation for greater than 8 years, the service life of the melters has far exceeded design expectations. It is possible that the DWPF liquidus temperature approach is conservative, in that it may be possible to successfully operate the melter with a small degree of allowable crystallization in the glass. This could be a viable approach to increasing waste loading in the glass assuming that the crystals are suspended in the melt and swept out through the riser and pour spout. Additional study is needed, and development work for WTP might be leveraged to support a different operating limit for the DWPF. Several recommendations are made regarding considerations that need to be included as part of the WTP crystal tolerant strategy based on the DWPF development work and operational data reviewed here. These include: Identify and consider the impacts of potential heat sinks in the WTP melter and glass pouring system; Consider the contributions of refractory corrosion products, which may serve to nucleate additional crystals leading to further accumulation; Consider volatilization of components from the melt (e.g., boron, alkali, halides, etc.) and determine their impacts on glass crystallization behavior; Evaluate the impacts of glass REDuction/OXidation (REDOX) conditions and the distribution of temperature within the WTP melt pool and melter pour chamber on crystal accumulation rate; Consider the impact of precipitated crystals on glass viscosity; Consider the impact of an accumulated crystalline layer on thermal convection currents and bubbler effectiveness within the melt pool; Evaluate the impact of spinel accumulation on Joule heating of the WTP melt pool; and Include noble metals in glass melt experiments because of their potential to act as nucleation sites for spinel crystallization.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2014

High Temperature Viscosity Model For Glassy Slags Produced From The Air Products Municipal Waste Gasification Process

Air Products, Inc. (AP) is developing a technology that uses plasma-enhanced gasification to create syngas from Municipal Solid Waste (MSW), for the purpose of generating electricity at a large scale. The process is intended to convert the inorganic components in MSW to a slag that flows easily through and from the gasifier. AP and the Savannah River National Laboratory (SRNL) have established a Cooperative Research and Development Agreement (CRADA) to improve the properties of the slag material produced from MSW gasification. A primary objective for AP is the development of a viscosity model, which can be used to predict the viscosity of the slag produced in the gasification process as a function of its composition in order to ensure that the incoming feeds will ultimately yield slag that can effectively be poured from the gasifier. In addition, the development of such a model could allow AP to determine the type and amount of additives to mix with the incoming MSW to target a specific viscosity range as well as identify waste compositions that could lead to difficulties during processing.

high temperature↗
DOE OSTI2014

Road Map for Development of Crystal-Tolerant High Level Waste Glasses

The U.S. Department of Energy (DOE) is building a Tank Waste Treatment and Immobilization Plant (WTP) at the Hanford Site in Washington to remediate 55 million gallons of radioactive waste that is being temporarily stored in 177 underground tanks. Efforts are being made to increase the loading of Hanford tank wastes in glass while meeting melter lifetime expectancies and process, regulatory, and product quality requirements. This road map guides the research and development for formulation and processing of crystal-tolerant glasses, identifying near- and long-term activities that need to be completed over the period from 2014 to 2019. The primary objective is to maximize waste loading for Hanford waste glasses without jeopardizing melter operation by crystal accumulation in the melter or melter discharge riser. The potential applicability to the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF) will also be addressed in this road map. The planned research described in this road map is motivated by the potential for substantial economic benefits (significant reductions in glass volumes) that will be realized if the current constraints (T 1% for WTP and T L for DWPF) are approached in an appropriate and technically defensible manner for defense waste and current melter designs. The basis of this alternative approach is an empirical model predicting the crystal accumulation in the WTP glass discharge riser and melter bottom as a function of glass composition, time, and temperature. When coupled with an associated operating limit (e.g., the maximum tolerable thickness of an accumulated layer of crystals), this model could then be integrated into the process control algorithms to formulate crystal-tolerant high-level waste (HLW) glasses targeting high waste loadings while still meeting process related limits and melter lifetime expectancies. The modeling effort will be an iterative process, where model form and a broader range of conditions, e.g., glass composition and temperature, will evolve as additional data on crystal accumulation are gathered. Model validation steps will be included to guide the development process and ensure the value of the effort (i.e., increased waste loading and waste throughput). A summary of the stages of the road map for developing the crystal-tolerant glass approach, their estimated durations, and deliverables is provided.

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

Upgrade to Ion Exchange Modeling for Removal of Technetium from Hanford Waste Using SuperLig ® 639 Resin

This report documents the development and application of computer models to describe the sorption of pertechnetate [TcO 4 - ], and its surrogate perrhenate [ReO 4 - ], on SuperLig ® 639 resin. Two models have been developed: 1) A thermodynamic isotherm model, based on experimental data, that predicts [TcO 4 - ] and [ReO 4 - ] sorption as a function of solution composition and temperature and 2) A column model that uses the isotherm calculated by the first model to simulate the performance of a full-scale sorption process. The isotherm model provides a synthesis of experimental data collected from many different sources to give a best estimate prediction of the behavior of the pertechnetate-SuperLig ® 639 system and an estimate of the uncertainty in this prediction. The column model provides a prediction of the expected performance of the plant process by determining the volume of waste solution that can be processed based on process design parameters such as column size, flow rate and resin physical properties.

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

Upgrade to Ion Exchange Modeling for Removal of Technetium from Hanford Waste Using SuperLig ® 639 Resin

This report documents the development and application of computer models to describe the sorption of pertechnetate [TcO 4 ⁻], and its surrogate perrhenate [ReO 4 ⁻], on SuperLig ® 639 resin. Two models have been developed: 1) A thermodynamic isotherm model, based on experimental data, that predicts [TcO 4 ⁻] and [ReO 4 ⁻] sorption as a function of solution composition and temperature and 2) A column model that uses the isotherm calculated by the first model to simulate the performance of a full-scale sorption process. The isotherm model provides a synthesis of experimental data collected from many different sources to give a best estimate prediction of the behavior of the pertechnetate-SuperLig ® 639 system and an estimate of the uncertainty in this prediction. The column model provides a prediction of the expected performance of the plant process by determining the volume of waste solution that can be processed based on process design parameters such as column size, flow rate and resin physical properties.

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

Upgrade to Ion Exchange Modeling for Removal of Technetium from Hanford Waste Using SuperLig ® 639 Resin

This report documents the development and application of computer models to describe the sorption of pertechnetate [TcO 4 ⁻], and its surrogate perrhenate [ReO 4 ⁻], on SuperLig ® 639 resin. Two models have been developed: 1) A thermodynamic isotherm model, based on experimental data, that predicts [TcO 4 ⁻] and [ReO 4 ⁻] sorption as a function of solution composition and temperature and 2) A column model that uses the isotherm calculated by the first model to simulate the performance of a full-scale sorption process. The isotherm model provides a synthesis of experimental data collected from many different sources to give a best estimate prediction of the behavior of the pertechnetate-SuperLig ® 639 system and an estimate of the uncertainty in this prediction. The column model provides a prediction of the expected performance of the plant process by determining the volume of waste solution that can be processed based on process design parameters such as column size, flow rate and resin physical properties.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Rapid Temperature Swing Adsorption using Polymeric/Supported Amine Hollow Fibers

This project is a bench-scale, post-combustion capture project carried out at Georgia Tech (GT) with support and collaboration with GE, Algenol Biofuels, Southern Company and subcontract to Trimeric Corporation. The focus of the project is to develop a process based on composite amine-functionalized oxide / polymer hollow fibers for use as contactors in a rapid temperature swing adsorption post-combustion carbon dioxide capture process. The hollow fiber morphology allows coupling of efficient heat transfer with effective gas contacting, potentially giving lower parasitic loads on the power plant compared to traditional contacting strategies using solid sorbents.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Final Technical Report for Department of Energy Award DE-SC0010857, “Towards parameterization of root-rock hydrologic interactions in the Earth System Model”

The goal of the project is to understand how plants survive droughts, as the decimation of transpiration could shift the surface energy balance from latent heat to sensible heat, leading to warming of the lower atmosphere and amplification of drought. The hypothesis we investigated is that there is a store of moisture in the weathered bedrock below the organic soil mantle, so that plants that have roots deep enough to access this moisture reservoir could survive drought. We developed a new stochastic parameterization of hydraulic conductivity that introduces heterogeneity into the traditional formulation and captures the preferential flow through the weathered bedrock (Vrettas and Fung, 2015). With the new parameterization in the Richards equation, we succeeded in reproducing the fluctuations of the water table in seven well locations over six years. We also and carried out a series of model experiments that explore how subsurface properties impact evapotranspiration (ET) in a Mediterranean climate where a significant portion of ET is observed to take place in the dry and sunny summer when the precipitation is insufficient to meet the demand. Our results show that hydraulic redistribution is important for sustaining ET in the dry seasons when the vertical gradient in water potential is large. The results highlight the importance of lithology, species composition and root function for ET, especially under dry conditions.

58 GEOSCIENCES↗
DOE OSTI2018

One-pot catalytic conversion of biomass and alkanes: Kinetically coupling deoxygenation and dehydrogenation pathways

The stoichiometric hydrogen deficiency of carbohydrate feedstock implies that all conversion processes must remove oxygen and concurrently increase hydrogen content to form liquid hydrocarbon products. With support from the DOE Early Career program (DE-SC0008418) we have investigated the use of transition metal carbides for hydrodeoxygenation (HDO) chemistries using CH 4 and H 2 as co-reactants. We report that concurrently processing CH 4 and C 1 -C 3 oxygenates (oxygenate/CH 4 = 0.01-0.1) at 950 K on molybdenum carbide clusters encapsulated in zeolite micropores results in a staged bed with upstream CH 4 reforming and downstream CH 4 dehydroaromatization. Forward rates of CH 4 pyrolysis limited by CH 4 activation are unperturbed by the introduction of oxygenates with a (C/H) eff <0.25 after rigorously accounting for the thermodynamic reversibility caused by the H 2 produced in oxygenate reforming reactions and the fraction of the active catalyst bed deemed unavailable for CH 4 dehydroaromatization. A binomial distribution of 12 C/ 13 C isotopologues of CO is observed upon introduction of CH 3 13 COOH/CH 4 reactants suggesting that the introduction of oxygenates with a (C/H) eff <0.25 results in complete fragmentation of the oxygenate at these temperatures which in turn results in the invariance of forward rates of CH 4 pyrolysis when using CO 2 , HCOOH, or CH 3 COOH co-feeds. The stoichiometric loss of oxygen as CO when co-processing C 1 -C 3 oxygenates and CH 4 at these temperatures demonstrates that (C/H) eff =(C-O)/H is a single valued descriptor for oxygen removal on Mo/HZSM-5 catalysts. Separately, we have demonstrated the utility of transition metal carbides for vapor phase catalytic hydrodeoxygenation using molecular hydrogen with high selectivity for C-O cleavage and near absence of sequential hydrogenation reactions at atmospheric hydrogen pressure and illustrated that the faculty of transition metal carbides for selective hydrodeoxygenation arises due to oxygen-modification of the catalyst in situ. The oxophilic characteristics of these materials engender both the observed acid-metal catalytic bifunctionality and selectivity for hydrodeoxygenation. The evolution of catalyst surface composition and catalytic function under oxidative reaction environments proffers unique challenges in structural characterization of these materials and in this context, we developed and demonstrated the use of chemical titration and chemical transient studies to assess catalytic site identity and densities.

09 BIOMASS FUELS↗
DOE OSTI2019

A simple json format for storing and exchanging code calculation and experimental results

Calculation codes and code systems give their results in a plethora of different formats and/or files. For instance, MCNP gives a user the MCNP specific output file, the mctal file, the ptrac file, etc. while PARTISN has a PARTISN specific output file and a number of binary files with various kinds of information about the calculation. However, the results we are interested in are always the same. These can be single values such as the effective multiplication factor k eff or the effective delayed neutron fraction β eff . It can be histogram data (such as particle spectra, reaction rates, sensitivity profiles, etc.) or even pointwise data (for example the nuclide composition as a function of time, etc.). It is also worthwhile to note that this would also apply to experimental data that we may wish to compare with as well. Calculation and experimental results can basically be split into two components: attributes (or metadata) and the actual result itself. Attributes represent information about the result that are not necessarily required for its’ interpretation but that are still good to have. Often, these attributes are what we will want to filter results on. This means that these attributes are often the answer to specific questions we may have about the result. The following is a non exhaustive list of such basic questions: what type of result is it: e.g. the effective multiplication factor k eff , the effective delayed neutron fraction β eff , etc.; which case does it relate to: e.g. a specific ICSBEP case such as PU-MET-FAST-001-001; which code and version produced this result: e.g. MCNP 6.2, etc.; which nuclear data library was used to obtain the result: e.g. ENDF/B-VIII.0 or JEFF 3.3; which nuclide and reaction does it apply to (for reaction rates and sensitivity profiles); which volume in the geometry was it calculated in? The second component of the calculation or experimental result is the actual numerical data of the result. It is this data that we want to compare, exchange, plot, interpret, etc. It consists of values with optional uncertainties and units. It also includes the underlying structure (if any structure is required to interpret the result). Depending on the type of result, it may be a single value (e.g. the effective multiplication factor), an array of values (e.g. a reaction rate or particle spectrum) or even a multidimensional array. In order to exchange results between different organisations, for instance for benchmarking, people often resort to spreadsheets or custom text files that need to be filled out. While this approach works well if little information is to be exchanged, it can become cumbersome when dealing with large amounts of data (like for instance particle spectra for thousands of cases). In addition, such an approach does not always capture the metadata we may be interested in to allow for automated processing of these files. The purpose of this report is to propose a standardised json structure to store any type of result and present an associated python interface to interact with these results directly. For such a structure to be useful, it must fulfill a specific set of functional requirements that we try to meet with this proposal. The format must allow for the calculation result to stand by itself. This means that we should not have to look in multiple places to be able to understand it. For example, if the result relates to a particle spectrum, the group structure in which the result is given should be stored with it. The format should be code agnostic. This means that we do not need to know where it came from to understand it. The format should be result type agnostic. This means that the format must be generic enough so that we can even use it for results we have not thought of yet. The format should be relatively easy to interact with through different scripting or programming languages (i.e. the machine interface) while still providing a clean structure that can be used directly by any human.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2021

Trade-Offs Between Growth Rate and Other Fungal Traits

If we better understand how fungal responses to global change are governed by their traits, we can improve predictions of fungal community composition and ecosystem function. Specifically, we can examine trade-offs among traits, in which the allocation of finite resources toward one trait reduces the investment in others. We hypothesized that trade-offs among fungal traits relating to rapid growth, resource capture, and stress tolerance sort fungal species into discrete life history strategies. We used the Biolog Filamentous Fungi database to calculate maximum growth rates of 37 fungal species and then compared them to their functional traits from the fun fun database. In partial support of our hypothesis, maximum growth rate displayed a negative relationship with traits related to resource capture. Moreover, maximum growth rate displayed a positive relationship with amino acid permease, forming a putative Fast Growth life history strategy. A second putative life history strategy is characterized by a positive relationship between extracellular enzymes, including cellobiohydrolase 6, cellobiohydrolase 7, crystalline cellulase AA9, and lignin peroxidase. These extracellular enzymes were negatively related to chitosanase 8, an enzyme that can break down a derivative of chitin. Chitosanase 8 displayed a positive relationship with many traits that were hypothesized to cluster separately, forming a putative Blended life history strategy characterized by certain resource capture, fast growth, and stress tolerance traits. These trait relationships complement previously explored microbial trait frameworks, such as the Competitor-Stress Tolerator-Ruderal and the Yield-Resource Acquisition-Stress Tolerance schemes.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Effects of high concentrate rations on ruminal fermentation and microbiota of yaks

Ruminal microflora is closely correlated with the ruminant’s diet. However, information regarding the effect of high concentrate diets on rumen microflora in yaks is lacking. In the current study, 24 healthy male yaks were randomly assigned to two groups, each fed with different diets: less concentrate (LC; concentrate: coarse = 40: 60) and high concentrate (HC; concentrate: coarse = 80: 20) diets. Subsequently, a 21-day feeding trial was performed with the yaks, and rumen fluid samples were collected and compared using 16 s rRNA sequencing. The results showed that NH 3 -N, total VFA, acetate, butyrate, isobutyrate, and isovalerate were significantly higher in the HC group than that in the LC group ( p < 0.05), while microbial diversity and richness were significantly lower in the HC group ( p < 0.05). Principal coordinate analysis indicated that rumen microflora was significantly different in LC and HC groups ( p < 0.05). In the rumen, phyla Firmicutes and Bacteroidota were the most abundant bacteria, with Firmicutes being more abundant, and Bacteroidota being less abundant in the HC group than those found in the LC group. Christensenellaceae_R-7_group and Prevotella are the highest abundant ones at the genus level. The relative abundance of Acetitomaculum , Ruminococcus , and Candidatus_Saccharimonas were significantly higher in the HC group than that in the LC group ( p < 0.05), while the relative abundance of Olsenella was significantly lower in the HC group than in the LC group ( p < 0.05). Compared to the LC group, the relative abundance of Prevotella , Ruminococcus , and Candidatus_Saccharimonas was significantly higher in the HC group. The relative abundances of Prevotella , Prevotellaceae_UCG-003 , Olsenella , Ruminococcus , Acetitomaculum , Candidatus_Saccharimonas , and NK4A214_group were correlated with ruminal fermentation parameters ( p < 0.05). Furthermore, PICRUSt 2 estimation indicated that microbial genes associated with valine, leucine, and isoleucine biosynthesis were overexpressed in the rumen microflora of yaks in the HC group ( p < 0.05). Conclusively, our results suggest that high concentrate diets affect the microflora composition and fermentation function in yak rumen. The present findings would provide new insights into the health of yaks under high concentrate feeding conditions and serve as a potent reference for the short-term fattening processes of yaks.

Pang, Kaiyue↗
DOE OSTI2016

Reviews and syntheses: Australian vegetation phenology: new insights from satellite remote sensing and digital repeat photography

Phenology is the study of periodic biological occurrences and can provide important insights into the influence of climatic variability and change on ecosystems. Understanding Australia's vegetation phenology is a challenge due to its diverse range of ecosystems, from savannas and tropical rainforests to temperate eucalypt woodlands, semi-arid scrublands, and alpine grasslands. These ecosystems exhibit marked differences in seasonal patterns of canopy development and plant life-cycle events, much of which deviates from the predictable seasonal phenological pulse of temperate deciduous and boreal biomes. Many Australian ecosystems are subject to irregular events (i.e. drought, flooding, cyclones, and fire) that can alter ecosystem composition, structure, and functioning just as much as seasonal change. We show how satellite remote sensing and ground-based digital repeat photography (i.e. phenocams) can be used to improve understanding of phenology in Australian ecosystems. First, we examine temporal variation in phenology on the continental scale using the enhanced vegetation index (EVI), calculated from MODerate resolution Imaging Spectroradiometer (MODIS) data. Spatial gradients are revealed, ranging from regions with pronounced seasonality in canopy development (i.e. tropical savannas) to regions where seasonal variation is minimal (i.e. tropical rainforests) or high but irregular (i.e. arid ecosystems). Next, we use time series colour information extracted from phenocam imagery to illustrate a range of phenological signals in four contrasting Australian ecosystems. These include greening and senescing events in tropical savannas and temperate eucalypt understorey, as well as strong seasonal dynamics of individual trees in a seemingly static evergreen rainforest. We also demonstrate how phenology links with ecosystem gross primary productivity (from eddy covariance) and discuss why these processes are linked in some ecosystems but not others. We conclude that phenocams have the potential to greatly improve the current understanding of Australian ecosystems.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1967

Thermodynamic analysis of dilute ternary systems. 1. The Ag-Au-Sn system

The heats of solution of silver and gold in dilute Ag-Au-Sn alloys have been determined as a function of alloy composition using liquid metal solution calorimetry. From the values obtained, the various enthalpy interaction parameters in the liquid solutions have been calculated. The results are interpreted in terms of the probably bonding changes taking place between silver, gold and tin atoms.

P J Spencer↗
NASA NTRS1968

Thermodynamic analysis of dilute ternary systems. I.

The heats of solution of silver and gold in dilute Ag-Au-Sn alloys have been determined as a function of alloy composition using liquid metal solution calorimetry. From the values obtained, the various enthalpy interaction parameters in the liquid solutions have been calculated. The results are interpreted in terms of the probably bonding changes taking place between silver, gold and tin atoms.

P J Spencer↗
NASA NTRS1973

Optical constants of concentrated aqueous ammonium sulfate.

Using experimental data obtained from applying spectroscopy to a 39-wt-% aqueous ammonium sulfate solution, it is shown that, even though specific aerosol optical constants appear quite accurate, spectral variations may exist as functions of material composition or concentration or both. Prudent users of optical constant data must then include liberal data error estimates when performing calculations or in interpreting spectroscopic surveys of collected aerosol material.

Remsberg, E. E.↗