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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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Melter feed viscosity during conversion to glass: Comparison between low-activity waste and high-level waste feeds

During nuclear waste vitrification, a melter feed (generally a slurry-like mixture of a nuclear waste and various glass forming and modifying additives) is charged into the melter where undissolved refractory constituents are suspended together with evolved gas bubbles from complex reactions. Knowledge of flow properties of various reacting melter feeds is necessary to understand their unique feed-to-glass conversion processes occurring within a floating layer of melter feed called a cold cap. The viscosity of two low-activity waste (LAW) melter feeds were studied during heating and correlated with volume fractions of undissolved solid phase and gas phase. In contrast to the high-level waste (HLW) melter feed, the effects of undissolved solid and gas phases play comparable roles and are required to represent the viscosity of LAW melter feeds. This study can help bring physical insights to feed viscosity of reacting melter feeds with different compositions and foaming behavior in nuclear waste vitrification.

Jin, Tongan↗
DOE OSTI2021

Melting rate correlation with batch properties and melter operating conditions during conversion of nuclear waste melter feeds to glasses

The rate of conversion of nuclear waste melter feed to glass is affected by the selection of melter feed materials and by melter design and operation. The melting rate correlation (MRC) is an equation that relates the glass production rate with two types of variables: (1) feed and melt properties: conversion heat, cold-cap bottom temperature, and glass melt viscosity; and (2) melter design and operation parameters: melter geometry, melter operating temperature, and gas bubbling rate. The MRC shows good agreement for an extended melting-rate data set of high-level waste (HLW) melter feeds and a data set generated for low-activity waste (LAW) melter feeds. Laboratory observation of heated melter feed samples is often used to assess the cold-cap bottom temperature of HLW melter feeds (moderately foaming feeds), but this technique appears inadequate for LAW melter feeds (vigorously foaming feeds). For LAW feeds, an adequate assessment of the cold-cap bottom temperature was achieved using evolved gas analysis, which allows identification of the collapse of primary foam for oxidized feeds. This assessment shows that the cold-cap bottom temperature for vigorously foaming LAW feeds is higher than that for moderately foaming HLW feeds. When the results of MRC are compared, LAW feeds are generally less sensitive to the bubbling rate and melt viscosity, and more sensitive to the cold-cap bottom temperature than HLW feeds. The MRC qualifies as a promising tool to support the selection of melter feed materials and melter operating conditions, which is determined from expensive independent scaled melter experiments, and sophisticated mathematical models.

Lee, Seung Min↗
DOE OSTI2020

Viscosity of glass-forming melt at the bottom of high-level waste melter feed cold caps: Effects of temperature and incorporation of solid components

At the final stages of conversion of melter feed (glass batch) to molten glass, the transient glass-forming melt becomes a continuous liquid phase encapsulating dissolving solid particles and gas bubbles that produce primary foam at the bottom of the cold cap (the reacting melter feed in an electric glass melting furnace). The glass-forming melt viscosity plays a dominant role in primary foam formation, stability, and eventual collapse, thus affecting the rate of melting (the glass production rate per cold cap area). For several melter feeds designed for nuclear waste vitrification, we have traced the glass-forming melt viscosity during the final stages of feed-to-glass conversion as it changes in response to changing temperature and composition (resulting from dissolving solid particles). Starting with a relatively low values at the moment when the melt connects, melt viscosity reaches maximum within the primary foam layer and then decreases to its final melter-operating temperature value. We paid a particular attention to the cold-cap bottom—the boundary between the primary foam layer and the thermal boundary layer—where the melt viscosity affects the rate of melting predominantly through its effect on the temperature at which primary foam is collapsing.

Lee, Seung Min↗
DOE OSTI2023

A laboratory-scale compression feed screw for characterizing continuous feeding of dense granular materials

Compression feed screws are commonly used in biorefineries for the continuous feeding of biomass feedstock into reactors. Developing methods to assess the feasibility of feeding granular materials in a compression feed screw is critical for reducing solids handling issues during operation. A laboratory-scale compression feed screw has been built to measure critical process parameters of the feeding operation, namely the driving torque and the mass flow rate. The process parameters of two granular materials, microcrystalline cellulose Avicel PH-200 and milled corn stover are measured using the laboratory-scale feeder. The results show that a larger torque is required to feed corn stover than Avicel PH-200, even though the former consists of more compressible particles. Further, the device can capture real-time fluctuations in the process parameters during operation. Here, the laboratory-scale feeder can be used to compare the feeding of different granular materials and the measured parameters can be used to validate predictive models for a compression screw feeding process.

09 BIOMASS FUELS↗
DOE OSTI2019

Cold-cap formation from a slurry feed during nuclear waste vitrification

The time-temperature history of waste slurry feed during melting strongly affects various kinetic processes, such as reaction or dissolution rates, and, consequently, the melting rate. To analyze the time-temperature history of the feed in a cold-cap during nuclear waste vitrification, this work focuses on understanding how the main coldcap body forms, how the aqueous feed slurry interacts with the cold-cap, and estimating the cold-cap heat conductivity. To simulate the conditions during cold-cap formation, samples were prepared by rapid water evaporation from slurry feed. After water evaporated from the sample, a fresh slurry with tracer was poured onto the dry sample. X-ray fluorescence was then used to investigate the degree of penetration and/or mixing between the incoming slurry and the original sample. We show that the slurry does not interact or mix with the previously dry cold-cap crust, but that water-soluble components concentrate at the bottom of the boiling pools, where most of the water evaporates. Further, using the rate of water evaporation, the heat conductivity of the cold-cap was calculated from the measured temperature profile. The resulting conductivity is significantly higher than the values obtained in previous studies. We discuss the implications of the results for the cold-cap formation in the melter and for the development of the cold-cap mathematical model.

Hujova, Miroslava↗
DOE OSTI2019

Effect of sucrose on foaming and melting behavior of a low-activity waste melter feed

Reductants, such as sucrose, are added to nuclear waste melter feeds containing high fractions of nitrates and nitrites to reduce excessive foaming during feed-to-glass conversion and to decrease sulfate segregation and increase technetium retention. The sucrose effect on foaming and melting reactions during the conversion was examined using the feed volume expansion, thermogravimetric analysis, evolved gas analysis, X-ray diffraction, and scanning electron microscopy with energy dispersive X-ray spectrometry. Different sucrose additions were used to vary the carbon to nitrogen (C/N) ratio in the melter feed. As C/N ratio increased, the extent of foaming decreased and N2/NO ratio increased in the gas phase evolved. Significant foam suppression, rapid gas release at approximately 250°C, and reduction of transition metal oxides were observed at C/N > 1.1.

Appel, Connor J.↗
DOE OSTI2020

Determining Design Criteria for Feeding Biomass into a Fluidized Bed Using a Feed Screw

Many pathways have been discovered for the thermochemical conversion of biomass to products. These pathways often show very promising results on the benchtop scale and could be economical with the appropriate scale up. However, many of the fundamental challenges of scaling up thermochemical reactions are not well understood. One primary problem area that rarely receives much upfront attention is feeding large quantities of biomass into thermochemical reactors. As biomass transitions from ambient to reactor conditions, it undergoes chemical and physical changes that affect its flowability. Often these changes lead to agglomeration of feed particles within the transfer screw, leading to large clumps of feed entering and disrupting the fluidized bed, or more critically leading to a plug in the feed screw causing costly downtime and maintenance to remove. This transitional phase must be better understood for scale up of conversion technologies to be successful. The Feedstock-Conversion Interface Consortium (FCIC) is a collaboration of eight National Laboratories. FCIC is currently conducting research on screw feeding of biomass into thermochemical fluidized bed reactors. Heat transfer models have been constructed for the screw/reactor interface. Mechanical forces on biomass within screw feeder are being determined, as well as how those forces change by varying feed screw design. Feedstock physical and chemical properties are then being measured along these temperature and mechanical force gradients. This work will better inform feed screw design for scale up, increasing the success rate of future biorefineries. Discussion will include research approach, testing, and preliminary results.

09 BIOMASS FUELS↗
DOE OSTI2023

CFD Simulation of the Dosing Behavior within the Atomic Layer Deposition Feeding System

The effective operation of atomic layer deposition (ALD) feeding system is the premise of realizing specific ALD processes. In the present work, a detailed computational fluid dynamics (CFD) model of the feeding system has been developed and validated, which accounts for the roles of ALD valves and manifolds. A numerical simulation of the compressible fluid flow and heat/mass transfer within the feeding system was conducted. The dosing amounts and the spatiotemporal distributions of the precursors can be accurately predicted using the CFD model, as validated by experimental results. Different precursors, operating conditions, and structures of the feeding system were simulated and analyzed to examine the operating flexibility of the feeding system. The simulation results can be adopted as the upstream boundary conditions for simulations of the ALD process in the reaction chamber. The substrate-scale simulation indicates that the effect of the feeding system on the film deposition is highly related to the surface kinetics of ALD. The present work can serve as a guide for the development and optimization of different ALD-based processes via proper operation and even the design of the feeding system.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

A Method for Determining Bulk Density, Material Density, and Porosity of Melter Feed During Nuclear Waste Vitrification

Glassmelting efficiency largely depends on heat transfer to reacting glass batch (melter feed), which in turn is influenced by the bulk density (ρ b ) and porosity (ϕ) of the reacting feed as functions of temperature ( T ). Neither ρ b ( T ) nor ϕ( T ) functions are readily accessible from direct measurements. For the determination of ρ b , we monitored the profile area of heated feed pellets and calculated the pellet volume using numerical integration. For the determination of ϕ, we measured the material density of feeds quenched at various stages of conversion via pycnometry and then computed the feed density at heat‐treatment temperature using thermal expansion values of basic feed constituents.

Hilliard, Zachary↗
DOE OSTI2016

Integrated Waste Feed Qualification Program for Direct LAW Feed to WTP - 16421

The Hanford Tank Waste Treatment and Immobilization Plant (WTP) is a one-of-a-kind facility being designed and constructed for DOE by Bechtel National, Inc. (BNI) and principal subcontractor URS, to process and vitrify radioactive waste stored in underground tanks at the Hanford Site. The Tank Operations Contractor (TOC), Washington River Protection Solutions (WRPS), has the responsibility to retrieve, stage, pretreat, and deliver feed directly to the WTP Low Activity Waste (LAW) Vitrification Facility. The Direct Feed LAW (DFLAW) scenario is being considered by DOE as a strategy to treat Hanford tank wastes as soon as practicable. Extensive planning is underway by One System, an effort with joint participation by WTP and TOC personnel. The initial focus of One System is to achieve the required integration to ensure the waste feed meets acceptance requirements for processing in the TOC Low Activity Waste Pretreatment System (LAWPS) and WTP LAW facilities. The integrated waste feed qualification program approach for DFLAW was defined by One System during a four-day workshop. The effort resulted in a feasible approach for integrating LAWPS and LAW feed acceptance requirements to vitrify low-activity waste while complying with facility design basis, safety basis, waste acceptance criteria, and glass product compliance. The defined qualification program will provide a systematic approach to test newly staged feed campaigns at bench-scale using actual tank waste samples. The required integration and basis for obtaining sufficient and necessary data to qualify the feed for DFLAW facilities are discussed in this paper. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Enhanced nutrient uptake is sufficient to drive emergent cross-feeding between bacteria in a synthetic community

Abstract Interactive microbial communities are ubiquitous, influencing biogeochemical cycles and host health. One widespread interaction is nutrient exchange, or cross-feeding, wherein metabolites are transferred between microbes. Some cross-fed metabolites, such as vitamins, amino acids, and ammonium (NH4+), are communally valuable and impose a cost on the producer. The mechanisms that enforce cross-feeding of communally valuable metabolites are not fully understood. Previously we engineered a cross-feeding coculture between N2-fixing Rhodopseudomonas palustris and fermentative Escherichia coli. Engineered R. palustris excretes essential nitrogen as NH4+ to E. coli, while E. coli excretes essential carbon as fermentation products to R. palustris. Here, we sought to determine whether a reciprocal cross-feeding relationship would evolve spontaneously in cocultures with wild-type R. palustris, which is not known to excrete NH4+. Indeed, we observed the emergence of NH4+ cross-feeding, but driven by adaptation of E. coli alone. A missense mutation in E. coli NtrC, a regulator of nitrogen scavenging, resulted in constitutive activation of an NH4+ transporter. This activity likely allowed E. coli to subsist on the small amount of leaked NH4+ and better reciprocate through elevated excretion of fermentation products from a larger E. coli population. Our results indicate that enhanced nutrient uptake by recipients, rather than increased excretion by producers, is an underappreciated yet possibly prevalent mechanism by which cross-feeding can emerge.

Fritts, Ryan K.↗
DOE OSTI2017

The Integrated Waste Feed Delivery Plan for the Direct Feed Low-Activity Waste Mission - 17160

In order to begin tank waste treatment and reduce the risk to the liquid waste cleanup mission, a plan to directly feed the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Low-Activity Waste (LAW) Vitrification Facility before other WTP facilities has been implemented. Implementation requires another facility, the Low-Activity Waste Pretreatment System (LAWPS), to generate LAW from tank waste supernatant, along with upgrades to the existing tank farm facilities to provide waste feed and receive process returns. The Integrated Waste Feed Delivery Plan (IWFDP) presents the strategy for reliably delivering compliant waste feed to the LAWPS and subsequently WTP to safely and efficiently accomplish the direct feed LAW (DFLAW) mission. Modifications to existing systems and installation of new systems will be coordinated to meet WTP startup, commissioning, and processing needs. The IWFDP presents the process approach, feed campaign plans, and a list of infrastructure projects required to upgrade the DST system in order to support DFLAW start-up and operations. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2023

Anatomy of an agricultural antagonist: Feeding complex structure and function of three xylem sap‐feeding insects illuminated with synchrotron‐based 3D imaging

Abstract Many insects feed on xylem or phloem sap of vascular plants. Although physical damage to the plant is minimal, the process of insect feeding can transmit lethal viruses and bacterial pathogens. Disparities between insect‐mediated pathogen transmission efficiency have been identified among xylem sap‐feeding insects; however, the mechanistic drivers of these trends are unclear. Identifying and understanding the structural factors and associated integrated functional components that may ultimately determine these disparities are critical for managing plant diseases. Here, we applied synchrotron‐based X‐ray microcomputed tomography to digitally reconstruct the morphology of three xylem sap‐feeding insect vectors of plant pathogens: Graphocephala atropunctata (blue‐green sharpshooter; Hemiptera, Cicadellidae) and Homalodisca vitripennis (glassy‐winged sharpshooter; Hemiptera, Cicadellidae), and the spittlebug Philaenus spumarius (meadow spittlebug; Hemiptera, Aphrophoridae). The application of this technique revealed previously undescribed anatomical features of these organisms, such as key components of the salivary complex. The visualization of the 3D structure of the precibarial valve led to new insights into the mechanism of how this structure functions. Morphological disparities with functional implications between taxa were highlighted as well, including the morphology and volume of the cibarial dilator musculature responsible for extracting xylem sap, which has implications for force application capabilities. These morphological insights will be used to target analyses illuminating functional differences in feeding behavior.

3D imaging↗
DOE OSTI2018

Metagenomic analysis revealed the effects of goat milk feeding and breast feeding on the gut microbiome of Amur tiger cubs

Highlights: • First time to use metagenomic analyze the effects of different milk feeding patterns on gut microbiome of Amur tiger cubs. • Goat milk feeding and breast feeding can change the composition and functional structures of gut microbiota in Amur tiger. • Breastfed Amur tiger cubs and goat milk-fed Amur tiger cubs have distinct microbiotas in their guts. Ingredients in breast milk can help establish a healthy community of microorganisms in the infant gut, but no research exists regarding the effects of goat milk feeding and breast feeding on the gut microbiome of the Amur tiger, which is one of the most endangered species in the world.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Mouthpart conduit sizes of fluid-feeding insects determine the ability to feed from pores

Fluid-feeding insects, such as butterflies, moths, and flies (20% of all animal species), are faced with the common selection pressure of having to remove and feed on trace amounts of fluids from porous surfaces. Insects able to acquire fluids that are confined to pores during drought conditions would have an adaptive advantage and increased fitness over other individuals. Here we performed feeding trials using solutions with magnetic nanoparticles to show that butterflies and flies have mouthparts adapted to pull liquids from porous surfaces using capillary action as the governing principle. In addition, the ability to feed on the liquids collected from pores depends on a relationship between the diameter of the mouthpart conduits and substrate pore size diameter; insects with mouthpart conduit diameters larger than the pores cannot successfully feed, thus there is a limiting substrate pore size from which each species can acquire liquids for fluid uptake. In conclusion, given that natural selection independently favored mouthpart architectures that support these methods of fluid uptake (Diptera and Lepidoptera share a common ancestor 280 mya that had chewing mouthparts), we suggest that the convergence of this mechanism advocates this as an optimal strategy for pulling trace amounts of fluids from porous surfaces.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2017

Direct-Feed Low-Activity Waste: First Feed Flowsheet - 17108

In support of hot commissioning of the Low-Activity Waste Pretreatment System (LAWPS) and the Hanford Tank Waste Treatment and Immobilization Plant (WTP) LAW facility, the First Feed Flowsheet was initiated to project process stream characteristics and unit operation performance. The First Feed Flowsheet uses flowsheet models to simulate the preparation of the first feed campaign in Tank Farms and the subsequent feeding of the waste to the Low-Activity Waste Pretreatment System (LAWPS) and the WTP LAW facility. Three different models were used: a chemistry model of waste transfers developed in the Environmental Simulation Program (ESP), Washington River Protection Solutions' (WRPS') dynamic gPROMS{sup TM} LAWPS flowsheet model, and WTP's Dynamic G2 flowsheet model. Information from all three models showed favorable comparison of the waste feeds and secondary liquid wastes against waste compatibility assessment and waste acceptance criteria at multiple stages in the flowsheet. (authors)

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

Addressing the recovery of feeding rates in post-exposure feeding bioassays: Cyathura carinata as a case study

Post-exposure bioassays are used in environmental assessment as a cost-effective tool, but the effects of organism's recovery after exposure to pollutant has not yet been addressed in detail. The recoveries of post-exposure feeding rates after being exposed to two sublethal concentrations of cadmium during two different exposure periods (48 h and 96 h) were evaluated under laboratory conditions using the estuarine isopod Cyathura carinata. Results showed that feeding depression was a stable endpoint up to 24 h after cadmium exposure, which is useful for ecotoxicological bioassays. - Highlights: • We studied recovery of post-exposure feeding rates 48–96 h after cadmium exposure. • The assay is based on the isopod Cyathura carinata. • Post-exposure feeding inhibition is a stable sublethal endpoint.

54 ENVIRONMENTAL SCIENCES↗