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At least 181 records · Page 10

Process for Coating Substrates with Catalytic Materials

A process for forming catalysts by coating substrates with two or more catalytic components, which comprises the following sequence of steps. First, the substrate is infused with an adequate amount of solution having a starting material comprising a catalytic component precursor, wherein the thermal decomposition product of the catalytic component precursor is a catalytic component. Second, the excess of the solution is removed from the substrate. thereby leaving a coating of the catalytic component precursor on the surface of the substrate. Third, the coating of the catalytic component precursor is converted to the catalytic component by thermal decomposition. Finally, the coated substance is etched to increase the surface area. The list three steps are then repeated for at least a second catalytic component. This process is ideally suited for application in producing efficient low temperature oxidation catalysts.

Eric J Kielin↗

Thermal Modeling of a Novel Air-Cooled Temperature Swing Adsorption Compressor (AC-TSAC)

Contaminant removal technology, such as the Carbon Dioxide Removal Assembly (CDRA) on the International Space Station (ISS), is critical to Environmental Control and Life Support Systems (ECLSS), which enable humans to live and work in outer space. The CDRA includes an adsorbent bed, which absorbs CO 2 from the cabin air and releases it to a Sabatier reactor for water production when thermally cycled. An effective system would heat and cool the adsorbent quickly and uniformly to maximize the amount of CO 2 removed from the cabin and delivered to the Sabatier reactor. Air-Cooled Temperature Swing Adsorption Compressors (AC-TSAC) are promising for use downstream of the CDRA because they are a simple alternative to more mechanically-complex compressors, which are currently in use on the ISS. The current investigation addresses the thermal modeling of potential AC-TSAC designs. An initial thermal model was created and validated by comparing the model outputs to experimental data for the heating phase. Several design trades were conducted, including bed geometry (rectangular vs. cylindrical), bed structural material (i.e., the material that makes up the walls and shelves), and configuration of heat spreading elements within the bed. Also investigated is AC-TSAC performance sensitivity to the thermal conductivity of the adsorbent material and the heat pipes as well as the input power for heating. The results from these studies will inform the design of the next generation of the AC-TSAC, and the thermal modeling results will be further validated through testing.

Hannah S. Alpert↗

Thermochemical characterization of polymers for improved fire safety

Apparatus has been constructed for studying the thermal decomposition of polymers as a function of temperature. Such data is needed to evaluate the toxic threat presented by polymeric materials under fire conditions such as the smoldering fire of the type that occurs in closed areas such as coat closets in which anaerobic decomposition of polymers occurs. The apparatus allows the products of thermal decomposition to be collected and analyzed by infrared spectrometry and mass spectrometry. Data obtained from dog hair, an aromatic polyamide, polyphenylene sulfide, and polybenzimidazole are presented. It was found that significant amounts of toxic gas were evolved from dog hair at temperatures as low as 250 C, while temperatures in excess of 500 C were necessary in order for the evolution of toxic gas from the aromatic polymers to become significant.

Lerner, N. R.↗

Thermal Infrared Emission Spectroscopy of Synthetic Allophane and its Potential Formation on Mars

Allophane is a poorly-crystalline, hydrous aluminosilicate with variable Si/Al ratios approx.0.5-1 and a metastable precursor of clay minerals. On Earth, it forms rapidly by aqueous alteration of volcanic glass under neutral to slightly acidic conditions [1]. Based on in situ chemical measurements and the identification of alteration phases [2-4], the Martian surface is interpreted to have been chemically weathered on local to regional scales. Chemical models of altered surfaces detected by the Mars Exploration Rover Spirit in Gusev crater suggest the presence of an allophane-like alteration product [3]. Thermal infrared (TIR) spectroscopy and spectral deconvolution models are primary tools for determining the mineralogy of the Martian surface [5]. Spectral models of data from the Thermal Emission Spectrometer (TES) indicate a global compositional dichotomy, where high latitudes tend to be enriched in a high-silica material [6,7], interpreted as high-silica, K-rich volcanic glass [6,8]. However, later interpretations proposed that the high-silica material may be an alteration product (such as amorphous silica, clay minerals, or allophane) and that high latitude surfaces are chemically weathered [9-11]. A TIR spectral library of pure minerals is available for the public [12], but it does not contain allophane spectra. The identification of allophane on the Martian surface would indicate high water activity at the time of its formation and would help constrain the aqueous alteration environment [13,14]. The addition of allophane to the spectral library is necessary to address the global compositional dichotomy. In this study, we characterize a synthetic allophane by IR spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM) to create an IR emission spectrum of pure allophane for the Mars science community to use in Martian spectral models.

Rampe, E. B.↗

Dynamic Earth Energy Storage: Terawatt-year, Grid-scale Energy Storage Using Planet Earth as a Thermal Battery (GeoTES): Phase I Project (Final Report)

Grid-scale energy storage has been identified by the U.S. Department of Energy’s (DOE) Energy Storage Grand Challenge as a necessary technology to support the continued build-out of intermittent renewable energy resources required to attain a carbon-free energy future. To meet this goal, the 2018 Department of Energy Research and Innovation Act mandated the creation of a comprehensive program to accelerate the development and commercialization of next-generation energy storage technologies. One of numerous energy storage technology options is the storage of excess energy as heated geothermal brine in suitable geologic formations. This concept, known as reservoir thermal energy storage (RTES), geologic thermal energy storage (GeoTES), aquifer thermal energy storage (ATES), etc., relies on the storage of thermal energy in geologic formations for recovery and use in large-scale direct use geothermal (e.g., district heating, industrial processes, etc.) and electrical power generation applications. This thermal energy is derived from excess or waste heat from any high-temperature heat source, such as concentrated solar or from conventional thermal/nuclear generation. As such, RTES can potentially play a significant role in meeting the energy storage shortfall in the coming decades. RTES can provide energy arbitrage through both the storage and production of thermal energy stored in geologic formations for direct use applications and can serve as a source of hot fluids that can be used to generate electricity to support peak demand ramping, thus easing stress on transmission and distribution. This energy storage option has geographic benefits in that energy can be stored locally or regionally depending on the various needs/loads. RTES can also be located across an enormous geographic area, without the need for a traditional hydrothermal resource but where thermal gradients and hydrogeology allow economic exploitation of subsurface heat. The work conducted for this project includes (1) a review of lessons learned from past high-temperature RTES international projects; (2) geochemical experimental investigation and numerical simulations of potential domestic sedimentary reservoirs and (3) development of a thermo-hydrological-mechanical (THM) numerical simulation tool for optimizing formation properties and design parameters to maximize thermal energy storage performance.

15 GEOTHERMAL ENERGY↗

BBN photodisintegration constraints on gravitationally produced vector bosons

Gravitational production of massive particles due to cosmic expansion can be significant during the inflationary and reheating period of the Universe. If the particle also has non-gravitational interactions that do not significantly affect its production, numerous observational probes open up, including cosmological probes. In this work, we focus on the gravitational production of light vector bosons that couple feebly to the Standard Model (SM) particles. Due to the very feeble coupling, the light vector bosons never reach thermal equilibrium, and if the Hubble scale at the end of inflation is above 10 8 GeV, the gravitational production can overwhelm the thermal production via the freeze-in mechanism by many orders of magnitude. As a result, much stronger constraints from the Big Bang Nucleosynthesis (BBN) can be placed on the lifetime and mass of the vector bosons compared to the scenario where only thermal production is considered. As an example, we study the sub-GeV scale dark photons, which couple to the SM only through kinetic mixing, and derive constraints on the mass and kinetic mixing parameter of the dark photon from the photodisintegration effects on the light element abundances relevant at the end of the BBN when the cosmic age was around 10 4 s.

79 ASTRONOMY AND ASTROPHYSICS↗

SERDP PFAS Database

The PNNL-PFAS database was constructed to provide quantitative infrared spectra of per- and polyfluoroalkyl substances (PFAS) in the gas phase. These fluorine-rich, organic compounds have been used as non-flammable solvents, cleaning agents, and in the manufacture of a diverse variety of consumer products. Due to their widespread use and relative inertness, PFAS have accumulated in the natural environment, and exposure to these chemicals may be linked to harmful health effects. Development of methods for detecting and remediating PFAS contamination are thus active areas of research. This database supports PFAS investigations where gas-phase infrared signatures may be measured (e.g., during treatment by thermal decomposition). The database currently contains infrared spectra for 15 compounds; these were selected based on the potential of these compounds being thermal degradation products of the manufactured chemicals mentioned above. • Additional compounds will be added to the database in the future. • Additional information about the database may be obtained from [link to future paper about the PFAS database].

PFAS, infrared(IR)spectroscopy, DATABASE, FTIR, sp↗

Be-10 and Cl-36 depth profiles in an Apollo 15 drill core

The present study of galactic cosmic ray production profiles by means of tandem accelerator mass spectrometry has measured cosmic ray-produced Be-10 and Cl-36, whose half-attenuation lengths are respectively calculated to be 120 and 132 g/sq cm. The measured half-attenuation lengths for Be-10 are noted to be slightly longer than predicted by the Reedy-Arnold (1972) theoretical model. Secondary thermal neutron production from Cl-35 is invoked as an explanation for the flatter and deeper maximum seen in the Cl-36 profile.

Nishiizumi, K.↗

Building energy efficiency and load flexibility optimization using phase change materials under futuristic grid scenario

This work investigates the energy savings and load flexibility capacity of phase change material (PCM) integrated into building envelope under a future energy generation scenario, where 80% of the energy load comes from renewable sources. Using community-scale modeling, we first determine the net thermal storage required to fully manage the demand variability at a utility grid, and then using whole-building simulations we optimize operating parameters - such as PCM thickness, latent heat, interior setpoint profile, PCM distribution, and heat transfer coefficient - to determine the optimal conditions required for maximum energy reduction and load flexibility without compromising occupants' thermal comfort. The optimal PCM-integrated envelope proposed in this study can provide annual load flexibility up to 33.6% and annual energy savings up to 10.8% in a lightweight residential building located in Baltimore, MD. This study is relevant given the increasing contributions of renewable energy in the total energy generation mix, leading to a significant time-imbalance between peak energy demand and peak energy production. While thermal energy storage using PCM is a recognized technique, there is no known prior study dedicated to examining the thermal performance of PCM-integrated envelope under future energy generation scenarios. This study bridges the research gap by investigating a practical way to implement PCMs in the buildings and maximize the energy efficiency as well as load flexibility related benefits.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Preprocessing of municipal solid waste towards thermal insulating material

Municipal solid waste (MSW) is one of the significant challenges in today’s world. A continuous surge in population, increasing living standards, and rapid urbanization are generating an enormous quantity of MSW. For example, the Environmental Protection Agency (EPA) reported that the total generation of MSW in the United States in 2018 was 292.4 million tons. Improper management of this MSW often leads to the release of greenhouse gases, emission of particulate matters, and formation of dioxins, which all ultimately contributes to climate change. Recycling these wastes via landfills with gas recovery and/or energy and material production via thermal and chemical conversions could be viable options to manage these challenges. Depending on the inherent chemical and structural properties of unrecycled wastes, the carbon structures can be tailored for processing and reuse in manufacturing of structural composites, building materials such as insulation, carbon dense reactant materials such as activated carbon, and so on. According to the EPA’s estimation, MSW in the United States is approximately 23% paper and paperboard, 12% plastics, 6% wood and 6% is textiles. Thus, this research focused on the feasibility of using the MSW as insulation material for the construction sector. The goal of this work was to determine the range of particle sizes, consolidation ratios, and component blends that can achieve insulation R-values within at least 70% that of traditional blown cellulose fiber. To achieve this goal, we designed the testing matrix based on five different component blends, three different particle sizes, and three different compaction level. An American Society for Testing and Materials (ASTM) method (C-739) was used to measure the R-value of the insulation material. Results showed that, adding more paper component in addition to smaller particle size and loose compaction made the insulation similar to the traditional blown cellulose fiber insulation as the R-value was within a range of 2.5-3.0 per inch.

42 ENGINEERING↗

Dilepton Program with Time-of-Flight Detector at the STAR Experiment

Pairs of lepton and antilepton (dilepton) in a continuous mass range are one of the most experimentally challenging and golden probes of the quark-gluon plasma (QGP) produced in heavy ion collisions because they do not strongly interact with the hot and dense medium, and reflect the properties of the medium at the time the dilepton is generated. The measurements of dileptons require lepton identification with high purity and high efficiency at large detector acceptance. STAR is one of two large experiments at the relativistic heavy ion collider with a primary goal of searching for the QGP and studying its properties. The STAR experiment launched a comprehensive dielectron (e + e - ) program enabled by the time-of-flight (TOF) detector that had been fully installed in 2010. In this article, we review the decade-long R&D, the construction and performance of the STAR TOF detector, and dielectron measurements, including thermal dielectron production and dielectron production from the Breit–Wheeler process. Future perspectives are also discussed.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

SIMS CHARACTERIZATION OF NITROGEN DOPING OF LCLS-II-HE PRODUCTION CAVITIES

The thermal diffusion of nitrogen into the surface of niobium has been shown to yield superior low-loss SRF performance. An effective solution was identified and promptly employed in the production of cryomodules for LCLS-II. With added experience and R&D, a modified process was chosen for use in the upgrade for LCLS-II-HE. Largely motivated by this circumstance, supporting research has significantly refined the technique for making calibrated secondary ion mass spectrometry (SIMS) measurements of the N concentration depth profiles produced by production processes. Standardized reference samples were included with four HE production cavities in their N-doping furnace runs. We report the calibrated dynamic SIMS depth profiles of N, C, and O for these samples, together with the cryogenic acceptance test performance of the associated cavities. Interpretation and comparison with similar samples acquired in other furnaces highlights the importance of intentional process quality control of furnace conditions.

Reece, Charles↗

SIMS CHARACTERIZATION OF NITROGEN DOPING OF LCLS-II-HE PRODUCTION CAVITIES

The thermal diffusion of nitrogen into the surface of niobium has been shown to yield superior low-loss SRF performance. An effective solution was identified and promptly employed in the production of cryomodules for LCLS-II. With added experience and R&D, a modified process was chosen for use in the upgrade for LCLS-II-HE. Largely motivated by this circumstance, supporting research has significantly refined the technique for making calibrated secondary ion mass spectrometry (SIMS) measurements of the N concentration depth profiles produced by production processes. Standardized reference samples were included with four HE production cavities in their N-doping furnace runs. We report the calibrated dynamic SIMS depth profiles of N, C, and O for these samples, together with the cryogenic acceptance test performance of the associated cavities. Interpretation and comparison with similar samples acquired in other furnaces highlights the importance of intentional process quality control of furnace conditions.

Reece, Charles↗

A Multidisciplinary Approach to Integrated Energy Systems: Advanced Nuclear Plants with Thermal Storage for Dynamic and Flexible Operation in Diverse Markets

Energy supply, distribution, and demand are continuously evolving in accordance with the integration of new power generation sources. In the United States, there is a progressive shift toward incorporating fluctuating energy sources such as wind and solar into the energy mix, alongside the distributed generation. Simultaneously, we are seeing a revolution in consumer technologies such as electric vehicles, energy devices for both residential and commercial use, and industrial processes—all contributing to a fundamental change in energy consumption dynamics. These scenarios have led to huge demand for enhanced flexibility from nuclear power plants (NPPs), requiring them to operate with unprecedented adaptability. Furthermore, advanced NPPs (A-NPPs) could potentially apply to scenarios in which power generation flexibility is prioritized over its current and conventional baseload generation capacity for traditional demand patterns. The present work covers several configurations for coupling nuclear energy production with thermal energy storage (TES). Previous work evaluated systems entailing a simple nuclear-TES configuration that used steam as a heat source for the TES of three different advanced reactors (ARs), but its heat diversion ratio (HDR) for charging was limited. The present work proposes a new configuration that features full decoupling of the nuclear reactor and the power cycle, using reactor coolant (i.e., gas) as a heat source for the TES and offering a theoretically unlimited HDR. This configuration is, however, more complex, as both high- and low-temperature TES (HT-TES and LT-TES) systems are required in order to cover the extended temperature range. Although this configuration imposes certain limitations on the discharge system configuration, it also presents the opportunity to design a more efficient system. For this case in particular, a steam reheat cycle is advantageous. Conventional TES systems take advantage of nominal efficiency when discharging, whereas the reheat cycle in the fully decoupled TES system affords a significant efficiency increase over conventional cases. Material selection, component/equipment sizing, and costing analyses were performed, followed by economic dispatch and size optimization. Dynamic models were developed for the decoupled system in order to generate insights into aspects of off design operation (e.g., drops in cycle efficiency), and these models enable exploration of potential mitigation strategies for addressing such drops. The models also highlight the need to design fail-safes that ensure continuous operational stability and minimize the impact of power ramping on the reactor parameters.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Plasma Chemical Conversion and Resource Generation Beyond Low-Earth Orbit

As humanity gears up for its return to the moon after more than half a century, collaborative efforts between NASA, Artemis Accords Partners, and private industry are underway to establish the necessary infrastructure and technologies for lunar habitation and eventual Mars exploration. However, the traditional ISS resupply and waste management model is impractical and economically infeasible for prolonged missions to the Moon and Mars. Advanced chemical conversion technologies are needed to generate vital consumable products from local planetary resources (ISRU) and recycled gasses and waste within semi-closed loop life-support systems. Low-temperature plasma reactors are emerging power-to-gas technologies with the potential to facilitate various chemical synthesis processes with hardware commonality and redundancy. In plasma-based systems, electrical power is used to ionize a feedstock gas, creating a highly reactive environment that leverages electron excitation chemistry to break stable molecular bonds and form value added products. Unlike thermal chemical processes, plasma reactors operate at non-equilibrium conditions, allowing for lower-temperature operation and instantaneous start-up, making them adaptable to intermittent power availability. Moreover, their scalability permits deployment in both portable astronaut systems and large-scale industrial setups for colonies. One promising application of plasmas is for CO 2 conversion. Carbon dioxide comprises 96% of the Martian atmosphere and is a byproduct of human respiration, which typically must be scrubbed and vented from space habitats. A plasma source integrated with membrane separation technology could generate a stream of oxygen for life support and rocket propellant. CO 2 splitting may also be beneficial as a precursor to manufacture carbon-based products and fuels in situ, like methane, methanol, and polyethylene. Plasma-assisted CO 2 conversion is a simpler case to study without the concern of selectivity and is the first step toward complex chemical synthesis. This work presents preliminary experimental case study from a plasma reactor for CO 2 conversion and casts a vision for the potential of plasma technologies in a sub-architecture for resource production to enable the next generation of human spaceflight activities.

Plasma↗

An Uncertainty-Informed and High-Fidelity Performance Forecasting Framework for Heliostat Fields

Concentrating Solar Thermal (CST) tower systems employ heliostat fields to direct solar energy to a central receiver, which then transfers the heat either directly to a thermal process (e.g., steam production) or to a thermal energy storage system for future use. Heliostat fields compose a significant proportion of the project costs of a CST tower system and the performance of the heliostats determines a plant's productivity at a given location. While CST characterization tools such as SolarPILOT and System Advisor Model (SAM) include a large collection of inputs that influence the performance of a CST tower system, many are uncertain prior to the development of the project and may have a significant impact on the overall energy delivery and profitability of a project; moreover, the fidelity of these models under default conditions may be insufficient to determine the value of component improvements such as those under development in the Heliostat Consortium. This work introduces a Monte Carlo simulation framework that incorporates uncertainty in key performance parameters to generate confidence intervals and percentile estimates for a CST solar field's energy delivery.

14 SOLAR ENERGY↗

Gas generation and intramolecular isotope study in laboratory pyrolysis of the Springfield coal from the Illinois Basin

Position-specific (PS) isotopes of propane have been proposed as a potential geochemical tool to decipher various geological processes (e.g., thermal cracking, biodegradation, H exchange) in natural reservoirs. The limited studies have been conducted on the PS isotopes of propane from the pyrolysis gases from marine shales, and natural gases sourced from lacustrine and marine kerogens, but little is known on gases produced from the humic kerogen. Here, this study investigated the PS δ 13 C of propane in the closed-system pyrolysis of the Springfield coal, Illinois Basin, Indiana, at 310 to 470 °C (Easy %Ro: 0.76 to 3.07). The C kinetic isotope effect (KIE) of CH 4 produced in both this study and previous low-temperature pyrolysis of the same coal indicates the cleavage of C—O bonds is the main generation pathway at the early kerogen cracking stage, followed by the breakdown of alkyl groups. At the wet-gas cracking stage, C 3 H 8 production from thermally stable compounds has a significant influence on the bulk and position-specific C KIE in the pyrolysis of marine Woodford kerogen and Springfield coal. According to the PS δ 13 C of propane, the central site is likely more enriched in 13 C and the δ 13 C of the terminal site is relatively heterogeneous within the propyl group attached to different functional groups of the gas-prone kerogen. Our findings based on the pyrolysis experiments and natural gas samples indicate thermal cracking and biodegradation appear to alter the δ 13 C cen values more significantly than the δ 13 C ter values of propane. The larger magnitude of ΔC c-t in the kMC simulations (Peterson et al., 2018) compared with those from the marine shale and coal possibly implies the non-random distributions of 13 C of propane precursors in the kerogens. As a new dimension of intramolecular isotopic information of propane, the PS δ 13 C values can contribute to fingerprinting the gas origins and identifying the various geological processes (e.g., kerogen cracking, wet-gas cracking, microbial activities) in sedimentary basins.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Outgassing of casted and 3D printed silicones

Outgassing of 3D printed and casted silica-filled silicones was studied using a standard ASTM E-595 procedure and a modified Soreq’s method that allows very sensitive measurements of the outgassing kinetics even at low temperatures, 20 – 50 °C. We studied three different silica-filled silicones, non-porous cased M9787, and 3D printed LL50 and 40P materials. The present report shows that vacuum outgassing products of polysiloxane-based materials include multiple species. In addition to chemisorbed and physisorbed water outgassing, previously studied by TPD, polymer fragments of varying sizes evaporate as well. The chemical composition of the condensable volatile species collected on a Germanium substrate, was analyzed by FTIR. It was shown that all studied materials produce mostly PDMS-based outgassing products that form stable droplet-like structure on the Ge substrate. The highest amount of the condensable volatile species was measured for LL50. Isothermal TGA in nitrogen atmosphere of the LL50 material was compared to the standard vacuum outgassing. The results of TGA showed lower mass loss and higher water regain. The kinetics of the outgassing at relatively low temperatures of 20, 30 and 50 °C was studied using Thermoelectric Quartz Crystal Microbalance (TQCM). The TQCM surface was held at -10 °C to enhance condensation of the outgassed moisture. The analysis presented here, when combined with the extensive previous work on moisture outgassing, provides a better understanding of the aging mechanism of polysiloxane-based materials. In this work we show that outgassing techniques, usually applied for qualification of polymers for space-related applications, may be used as a complementary method to study thermal degradation and aging of silica-based silicones. Our results indicate that the long-term degradation mechanics and thermal degradation products depend primarily on the chemical composition of silicone-based material and only slightly affected by the manufacturing process. Surprisingly, the surface-to-volume ratio of the 3D printed vs. casted/molded materials showed only minor effect on the outgassing kinetic parameters.

36 MATERIALS SCIENCE↗