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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 793 records · Page 44
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Characterization of a large-area iQID imager for safeguards applications

Environmental sampling and sample analyses by the International Atomic Energy Agency is a key method for verifying declarations in international safeguards agreements. Quantitative Digital Autoradiography for Environmental Samples is a system developed by Pacific Northwest National Laboratory to examine environmental swipe samples (ESS) prior to subsequent, destructive analysis. This approach is passive and noninvasive for imaging beta and gamma emissions, which transmit through the plastic bags containing the ESS. Alpha particle imaging is also possible with different ESS containers. This technology is based on a portable, real-time, event-counting, high spatial resolution system called iQID (ionizing-radiation Quantum Imaging Detector), which is made from commercial, off-the-shelf components. This includes a scintillator in direct contact with a micro-channel plate image intensifier and a lens for imaging the intensified scintillation events onto a CCD/CMOS camera. The QDARES large-area iQID includes a fiber-optic taper coupled to the image intensifier which increases the imaging area to a ~100 cm square with a 105 mm x 105 mm taper. In this study, we describe new characterization results, including spatial resolution, energy response, minimum detectable activity for several isotopes, detector uniformity, and count-rate capability.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2024

Enabling high-throughput enzyme discovery and engineering with a low-cost, robot-assisted pipeline

Abstract As genomic databases expand and artificial intelligence tools advance, there is a growing demand for efficient characterization of large numbers of proteins. To this end, here we describe a generalizable pipeline for high-throughput protein purification using small-scale expression in E. coli and an affordable liquid-handling robot. This low-cost platform enables the purification of 96 proteins in parallel with minimal waste and is scalable for processing hundreds of proteins weekly per user. We demonstrate the performance of this method with the expression and purification of the leading poly(ethylene terephthalate) hydrolases reported in the literature. Replicate experiments demonstrated reproducibility and enzyme purity and yields (up to 400 µg) sufficient for comprehensive analyses of both thermostability and activity, generating a standardized benchmark dataset for comparing these plastic-degrading enzymes. The cost-effectiveness and ease of implementation of this platform render it broadly applicable to diverse protein characterization challenges in the biological sciences.

36 MATERIALS SCIENCE↗
NASA NTRS2003

Microsample Characterization of Coatings for Grcop-84 for High Heat Flux Applications

A multidisciplinary Johns Hopkins University-NASA Glenn team is undertaking a collaborative research program to elucidate and model the thermal stability and mechanical integrity of candidate coatings for GRCop-84. GRCop-84 is a high conductivity, high strength copper alloy that was recently developed at NASA Glenn for use in high temperature, high heat flux applications. With potential applications in rocket motor combustion chamber liners, nozzle ramps and other actively cooled structures, this new material offers great potential for decreasing weight and increasing reliability of third generation reusable launch vehicles. Current emphasis has turned toward the development of environmentally resistant and thermal barrier coatings for this alloy. Metallic coatings such as NiCrAlY and Cu-8-30%Cr have shown promise in: prohibiting blanching, reducing dog-house failures, increasing operating temperatures and decreasing cooling requirements. The focus of this research program is to develop a fundamental understanding of the substrate-coating interactions that occur during thermal cycling (inter-diffusion, viscoplasticity, morphological evolution, crack formation, etc.) and to derive a science-based protocol for future coating selection, optimization and reliability assurance. The microsample tensile testing approach adopted for this study allows us to characterize small-scale and highly scale-specific coatings and properties in a way not possible by conventional means. In addition to providing much needed design data, the integration of microsample testing with detailed microstructural observations provides a mechanistic foundation for coating optimization and life prediction modeling.

Hemker, Kevin↗
DOE OSTI2016

Characterization of cellulose structure of Populus plants modified in candidate cellulose biosynthesis genes

Here, the recalcitrant nature of lignocellulosic biomass is a combined effect of several factors such as high crystallinity and high degree of polymerization of cellulose, lignin content and structure, and the available surface area for enzymatic degradation (i.e., accessibility). Genetic improvement of feedstock cell wall properties is a path to reducing recalcitrance of lignocellulosic biomass and improving conversion to various biofuels. An advanced understanding of the cellulose biosynthesis pathway is essential to precisely modify cellulose properties of plant cell walls. Here we report on the impact of modified expression of candidate cellulose biosynthesis pathway genes on the ultra-structure of cellulose, a key carbohydrate polymer of Populus cell wall using advanced nuclear magnetic resonance approaches. Noteworthy changes were observed in the cell wall characteristics of downregulated KORRIGAN 1 (KOR) and KOR 2 transgenic plants in comparison to the wild-type control. It was observed that all of the transgenic lines showed variation in cellulose ultrastructure, increase in cellulose crystallinity and decrease in the cellulose degree of polymerization. Additionally, the properties of cellulose allomorph abundance and accessibility were found to be variable. Application of such cellulose characterization techniques beyond the traditional measurement of cellulose abundance to comprehensive studies of cellulose properties in larger transgenic and naturally variable populations is expected to provide deeper insights into the complex nature of lignocellulosic material, which can significantly contribute to the development of precisely tailored plants for enhanced biofuels production.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2017

Technical Report: Understanding Functional Lyotropic Liquid Crystal Network Phase Self-Assembly and the Properties of Nanoconfined Water

Through the synergistic interplay of molecular dynamics (MD) simulations, chemical synthesis, and materials characterization by X-ray and neutron scattering techniques, this project investigated the phase behaviors of new classes of aqueous lyotropic liquid crystals (LLCs) and the properties of water nanoconfined within their pores. A portion of our studies focused on the synthesis of new classes of alkylsulfonic acid and alkylphosphonate amphiphiles, which were shown to undergo water-induced self-assembly to form a wide variety of nanostructured morphologies with unusually high degrees of long-range translational order observed by small- angle X-ray scattering (SAXS). Sample LLC morphologies that were observed include the lamellar (L!), tricontinuous double gyroid (G), hexagonally-packed cylinders (H), and low symmetry discontinuous micellar (I) Frank-Kasper phases. Since the G and H phases are the most promising for the development of selective ion transporting membranes for energy applications, we sought the characterize the structure and dynamics of water confined within the sub-3 nm pores of these LLCs using wide-angle neutron diffraction (WAND) and quasielastic neutron scattering (QENS) experiments performed at the Spallation Neutron Source at Oak Ridge National Laboratory. Using molecular dynamics (MD) simulations, we validated models for analyzing this QENS data to obtain water self-diffusion coefficients in LLC G and H phases of carboxylate and sulfonate surfactant LLCs as a function of the identities of their charge compensating counterions.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2022

Leveraging Nitrogen Linkages in the Formation of a Porous Thorium–Organic Nanotube Suitable for Iodine Capture

We report the synthesis, characterization, and iodine capture application of a novel thorium–organic nanotube, TSN-626, [Th 6 O 4 (OH) 4 (C 6 H 4 NO 2 ) 7 (CHO 2 ) 5 (H 2 O) 3 ]·3H 2 O. The classification as a metal–organic nanotube (MONT) distinguishes it as a rare and reduced dimensionality subset of metal–organic frameworks (MOFs); the structure is additionally hallmarked by low node connectivity. TSN-626 is composed of hexameric thorium secondary building units and mixed O/N-donor isonicotinate ligands that demonstrate selective ditopicity, yielding both terminating and bridging moieties. Because hard Lewis acid tetravalent metals have a propensity to bind with electron donors of rival hardness (e.g., carboxylate groups), such Th–N coordination in a MOF is uncommon. However, the formation of key structural Th–N bonds in TSN-626 cap some of the square antiprismatic metal centers, a position usually occupied by terminal water ligands. TSN-626 was characterized by using complementary analytical and computational techniques: X-ray diffraction, vibrational spectroscopy, N 2 physisorption isotherms, and density functional theory. TSN-626 satisfies design aspects for the chemisorption of iodine. The synergy between accessibility through pores, vacancies at the metal–oxo nodes, and pendent N-donor sites allowed a saturated iodine loading of 955 mg g –1 by vapor methods. Furthermore, the crystallization of TSN-626 diversifies actinide–MOF linker selection to include soft electron donors, and these Th–N linkages can be leveraged for the investigation of metal-to-ligand bonding and unconventional topological expressions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2003

Synthesis and Characterization of Chalcopyrite (CuInS2 and CuhInSe2) Colloidal Nanoparticles for Optoelectronic Applications via Low-Temperature Pyrolysis of Single-Source Precursors

Nanocrystalline (or quantum dot) materials hold potential as components of next-generation photovoltaic (PV) devices. The inclusion of quantum dots in PV devices has been proposed as a means to improve the efficiency of photon conversion (quantum dot solar cell), enable low-cost deposition of thin-films, provide sites for exciton dissociation, and pathways for electron transport. Quantum dots are also expected to be more resistant to degradation from electron, proton, and alpha particle radiation than the corresponding bulk material, a requirement for use in space solar ~sells. Chalcopyrite nanocrystals can be produced by low-temperature thermal decomposition of single-source precursors such as (PR3)2CuIn(ER')4 (R = Ph, R' = Et, E = S; R = R' = Ph, E = Se). Single-source precursors are molecules which contain all the necessary elements for synthesis of a desired material. Thermal decomposition of the precursor results in the formation of material with the correct stoichiometry as a nanocrystalline powder or a thin film, often at significantly lower temperatures than those typically employed for thin-film deposition by multi-source evaporation techniques, typically less than 500 C. We show that CuInSz and CuInSe2 nanocrystals can be synthesized from the precursors at temperatures as low as 250 C. The nanocrystals are characterized by optical spectroscopy, X-ray diffraction, and electron microscopy.

Castro, S. L.↗
NASA NTRS2011

LIDAR Metrology for Prescription Characterization and Alignment of Large Mirrors

We describe the use of LIDAR, or "laser radar," (LR) as a fast, accurate, and non-contact tool for the measurement of the radius of curvature (RoC) of large mirrors. We report the results of a demonstration of this concept using a commercial laser radar system. We measured the RoC of a 1.4m x 1m spherical mirror with a nominal RoC of 4.6 m with a manufacturing tolerance of 4600mm +/- 6mm. The prescription of the mirror is related to its role as ground support equipment used in the test of part of the James Webb Space Telescope (JWST). The RoC of such a large mirror is not easily measured without contacting the surface. From a position near the center of curvature of the mirror, the LIDAR scanned the mirror surface, sampling it with 1 point per 3.5 sq cm. The measurement consisted of 3983 points and lasted only a few minutes. The laser radar uses the LIDAR signal to provide range, and encoder information from angular azimuth and elevation rotation stages provide the spherical coordinates of a given point. A best-fit to a sphere of the measured points was performed. The resulting RoC was within 20 ppm of the nominal RoC, also showing good agreement with the results of a laser tracker-based, contact metrology. This paper also discusses parameters such as test alignment, scan density, and optical surface type, as well as future possible application for full prescription characterization of aspherical mirrors, including radius, conic, off-axis distance, and aperture.

Eegholm, B.↗
DOE OSTI2020

Plasma Facing Component Characterization and Correlation With Plasma Conditions in Lithium Tokamak Experiment-β

Lithium coatings in the Lithium Tokamak eXperiment (LTX) led to flat temperature profiles. The flat temperature profiles were observed along with a hot, low density edge, implying a broad, collisionless scrape-off layer (SOL). Additionally, in vacuo X-ray photoelectron spectroscopy (XPS) measurements established that lithium coatings evaporatively deposited onto high-Z plasma facing components (PFCs) became oxidized while retaining the ability to achieve good plasma performance long after lithium was applied to the PFCs. Longstanding theory predicted flat temperature profiles with low recycling walls, which was presumed to be due to hydrogen binding with elemental lithium to form lithium hydride. The presence of oxidized lithium, however, raised questions regarding the exact mechanism of hydrogen retention in LTX. To investigate these questions, the upgraded facility LTX- β includes a new sample exposure probe (SEP) for more detailed in vacuo analysis of PFC samples. The SEP is equipped with a vacuum suitcase capable of transporting samples representative of the LTX- β outer midplane PFCs to a stand-alone XPS system while maintaining pressures lower than the LTX- β base vacuum to limit the contamination between sample exposure and analysis. The low-energy resolution XPS system used in past experiments could only enable the determination of elemental percentages on the PFC sample surfaces. Because the new XPS system has higher energy resolution, it is more direct to assign chemical compounds to the measured binding energies. This capability has been confirmed by comparing XPS data from PFC test samples with measurements using a commercial high-resolution XPS system. Quartz crystal microbalances (QCMs) were used to quantify the thickness of the deposited lithium on the LTX- β PFCs. This article describes the application of the SEP to characterize the PFC surfaces using XPS and their relationship to plasma conditions.

Maan, Anurag↗
DOE OSTI2024

From phase decomposition to evaporation: A multi-modal evaluation of thermally degraded model lightweight high-entropy alloy

Lightweight high-entropy alloys (LHEAs) have the potential to replace conventional lightweight materials due to their superior mechanical properties and thermal stability. However, the thermal degradation pattern of LHEAs from phase decomposition to evaporation is not clear. We develop a new Al-based dual phase (FCC + HCP) LHEA—AlTi 0.45 CuZn, and further investigate its thermal degradation behavior for potential high-temperature structural applications. Using multimodal advanced characterization techniques such as differential scanning calorimetry/thermogravimetric analysis, scanning/transmission electron microscopy, and synchrotron X-ray diffraction/pair distribution function (XRD/PDF), a sequence of thermal degradation events beyond the thermal phase stability limit—between 250 and 360 °C—is observed. These include phase decomposition at ~360 °C, Zn evaporation at ~750 °C, and LHEA melting at 880 °C which results in ~25% cumulative weight loss. The formation of Al-Ti phase off the AlTi 0.45 CuZn matrix is due to the largest negative mixing enthalpy for Al-Ti than other binary pairs. Similarly, Zn evaporation from AlTi 0.45 CuZn LHEA is due to its faster evaporation rate than other constituent elements. The high-resolution synchrotron XRD and PDF results support the aforementioned observations; in addition, they reveal local atomic arrangements, local strain, and sluggish grain growth in the LHEA. Among other LHEAs of close density range (5.55 ≤ ρ ≤ 5.85 g/cc), the investigated LHEA exhibits outstanding nano-indentation hardness values due to the coupled grain size effect and HCP phase strengthening of the FCC matrix. As the search for LHEAs for lightweight applications grows, this study shows the potential use of AlTi 0.45 CuZn LHEA for structural applications even at elevated temperatures.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2019

Development of a Technical Standard for Radiological Characterization of DAW - 19552

Since the Manhattan Project, the U.S. Department of Energy (DOE) and its predecessor agencies have performed a wide mission involving nuclear materials and weapons development, production, testing, and modernization. While the initial mission components relied heavily upon reactor physics and chemistry, the environmental programs have increasingly relied upon development of more accurate and effective measurement methodologies to determine the radiological and chemical properties of the unique waste streams that were generated during the weapons production and testing mission. During the ongoing site cleanup program, the DOE laboratories and former production sites have developed a wide range of site-specific processes and procedures for conducting radiological characterization of dry active waste (DAW) that is managed as low-level radioactive waste. This has resulted in a Complex-wide variability among sites with respect to the methodologies and instrumentation used to characterize individual waste streams. The DAW-type waste was selected for development of a characterization standard since it is a simple, voluminous, and repetitive waste stream with a substantial knowledge base, established experience history at multiple site locations, and the potential for realization of programmatic benefits though standardization. Implementation of a consistent, standardized approach to DAW characterization will take advantage of multiple applications for a technology that is both mature and stable. The DAW characterization process is repetitive and lends itself to implementation at a wide range of operating locations - resulting in economies of scale, compliance with regulatory requirements, and consistent implementation of procedures which support design, operations, maintenance, and management of facilities, activities and environmental restoration programs. In response to a request from DOE, the Energy Facility Contractors Group (EFCOG) Waste Management Working Group (WMWG) is supporting the development of a new DOE Technical Standard for Radiological Characterization of DAW. The purpose of the proposed new standard is to provide a technical resource that integrates and enhances the utilization of current site-specific methodologies and processes. An EFCOG/WMWG technical team has prepared a Technical Basis Document (TBD) to support the development and utilization of the new standard. The TBD provides detailed reference information for use by site personnel when implementing the guidance to be provided in the standard. It also provides the rationale for and details concerning the recommended technical approaches for radiological characterization of representative DAW-type waste streams. The TBD is an essential resource and will be included as an appendix to the proposed standard. Formulation of the new standard will draw upon the information contained in the TBD in order to integrate and improve the utilization of current site-specific methodologies and processes. It will also include a comparison of current radiological characterization methodologies to determine which ones are most reliable and effective in producing relevant and valid data. In view of the long history and participation by several agencies in the regulation of nuclear programs, existing Voluntary Consensus Standards have also been identified in the TBD and will be referenced for relevancy and applicability to the new proposed standard. A Project Justification Statement (PJS) was also developed by the EFCOG/WMWG Team. Following internal Team review and approval by EFCOG, the draft PJS was submitted through Argonne National Laboratory (ANL) and the DOE Argonne Site Office Technical Standards Managers for review and approval by the DOE Argonne Site Office Manager. After resolution of comments and approval by the Manager, the PJS will be submitted to the DOE/HQ Technical Standards Program Manager (TSPM) for formal coordination. Following resolution of technical comments received during the PJS coordination process and receipt of a technical standards project number assigned by the TSPM, the Team will confirm the overall preparation schedule and develop an Internal Draft Technical Standard for coordination with the DOE Argonne Site Office. Following comment resolution, the Team will then prepare a Coordination Draft for submittal to the DOE Technical Standards RevCom review process and will respond to comments generated during this Complex-wide review. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Understanding the Impact of Dynamic Power Capping on Application Progress

Electrical power has become an important design constraint in high-performance computing (HPC) systems. On future HPC machines, power is likely to be a budgeted resource and thus managed dynamically. Power management software needs to reliably measure application performance at runtime in order to respond effectively to changes in application behavior. Execution time tells us little about how the science in the application is progressing toward an application-defined end goal. To the best of our knowledge, no study has defined or categorized online application progress in the context of power management. Based on semi-structured interviews with HPC application-specialists, we define an online notion of progress—an application-specific metric that can be monitored at runtime to provide a sense of the rate at which application science is being performed. Using instrumentation, we characterize and categorize the progress of various production scientific applications and benchmarks. We propose a model of the impact of dynamic power capping on application progress. By experimental evaluation, we show that our model accurately captures the general behavior of the progress of different classes of applications under a power cap. We believe that such a model is an important first step toward the design of more dynamic power management policies for HPC systems.

application progress↗
DOE OSTI2020

Study of Additive Manufacturing Application to Geothermal Technologies

Geothermal reservoir characterization, field construction, and reservoir operations are very technology intensive activities that contribute significantly to the cost of delivering electricity produced from geothermal resources. Many geothermal technologies, such as downhole tools and drilling equipment, have unusual material, design, and manufacturing considerations dictated by the harsh geothermal environment and extreme aspect ratios required for deployment in a borehole. An additional challenge that faces geothermal applications is the low tool production volume needed to support the industry. Whereas tens of thousands of Oil & Gas wells are drilled and completed in the U.S. annually, there are typically only tens of geothermal wells that are drilled and completed. If a tool typically used in Oil & Gas applications cannot be directly used for geothermal, then the cost associated with making the tool suitable for geothermal is often prohibitive. There is therefore a much smaller inventory of technologies available to geothermal as compared to Oil & Gas and the level of efficiency and sophistication associated with field practice suffers accordingly. A number of advanced manufacturing methods, such as additive manufacturing, have received increased R&D as well as commercial attention in recent years because of their ability to rapidly prototype complex parts. Additive manufacturing in particular provides an opportunity to increase the technology available to the geothermal industry by either reducing fabrication costs associated with complex components or enabling economic production of low volume parts where specialized tooling is often required. Additional potential benefits of additive manufacturing include increased design freedom to make higher performing parts that cannot be made conventionally, the ability to integrate components into assemblies without joining operations, and the ability to economically fabricate variations on design in cases, such as casting molds, where there are large up-front costs associated with tooling. We have recently completed a study that investigated technology needs, representative use cases, manufacturability, and a techno-economic framework for comparing conventional to additive manufacturing methods for geothermal applications. This paper will provide an overview of this recent effort, describe the different elements of the assessment, and summarize the key takeaways related to both the feasibility of using additive manufacturing for geothermal technology applications as well as the potential benefits and impacts.

Polsky, Yarom↗
DOE OSTI2016

Characterization of SiC-SiC accident tolerant fuel cladding after stress application

In this work, SiC-SiC tubes with representative LWR (water cooled reactor) cladding dimensions were subjected to cycles of out-of-pile thermal stress followed by quenching. Samples were held at elevated temperatures and dropped into a water bath to replicate the high thermal stresses generated during reflooding. The samples were then characterized to measure changes in strength, permeability, and structure. Results were evaluated both for quenching into room temperature and boiling water. The results show that SiC-SiC composite tubes quenched from 1000 Celsius degrees in air into a boiling water bath exhibited no increase in He leak rate through the cylinder wall up to a pressure difference of 34.5 kPa compared to the as-fabricated state. SiC-SiC composite tubes quenched from 300-400 C. degrees into room temperature water showed an increase in He leak rate compared to the as-fabricated state. We attribute this to the more severe thermal gradient generated through the wall thickness due to higher heat flux characteristic of nucleate boiling compared to film boiling. A persistent vapor film forms around the samples quenched into boiling water, whereas no vapor film forms for the samples quenched into room temperature water. Another important result is that not loss in strength was noted compared to unquenched samples and that the stresses generated by the quenching were not enough to cause fiber fracture.

36 MATERIALS SCIENCE↗
NASA NTRS1990

Scheduling periodic jobs that allow imprecise results

The problem of scheduling periodic jobs in hard real-time systems that support imprecise computations is discussed. Two workload models of imprecise computations are presented. These models differ from traditional models in that a task may be terminated any time after it has produced an acceptable result. Each task is logically decomposed into a mandatory part followed by an optional part. In a feasible schedule, the mandatory part of every task is completed before the deadline of the task. The optional part refines the result produced by the mandatory part to reduce the error in the result. Applications are classified as type N and type C, according to undesirable effects of errors. The two workload models characterize the two types of applications. The optional parts of the tasks in an N job need not ever be completed. The resulting quality of each type-N job is measured in terms of the average error in the results over several consecutive periods. A class of preemptive, priority-driven algorithms that leads to feasible schedules with small average error is described and evaluated.

Chung, Jen-Yao↗
NASA NTRS2019

Characterization of Flat-Plate Heat Pipe Functionality for Fuel Cell Application

For many exothermic systems such as proton exchange membrane (PEM) fuel cells, cooling is necessary to maintain consistent and uniform operating temperatures which are generally in the range of 60 to 80°C. A potential solution is a heat pipe employing the principle of conduction in combination with a phase change. The purpose of this study was to fully characterize the operation of a heat pipe with unique geometry designed for fuel cell heat removal at operating temperatures up to 100°C and to assess the suitability of the resulting performance for cooling system integration. Test variables consist of cold sink thermal contact conductance coefficient improving material usage, heat rejection temperature, contact pressure and area, heat pipe orientation, operational hours, and variability between units. The test results showed that heat pipe performance improves through increased condenser and heat sink contact pressure, thermal contact coating usage, greater condenser area utilization, and colder heat sink temperature. Higher initial heat pipe temperature and greater age or operation time reduce the heat pipe capabilities. Placing the condenser lower than the evaporator is the only heat pipe orientation that affects evaporator plate temperature. Condensing fluid in the lower section reduces heat transfer capacity as that orientation requires liquid water to transport by wicking against gravity.

Smith, Phillip J.↗
NASA NTRS2008

Using the HHT to Search for Gravitational Waves

Gravitational waves are a consequence of Einstein's theory of general relativity applied to the motion of very dense and massive objects such as black holes and neutron stars. Their detection will reveal a wealth of information about these mysterious objects that cannot be obtained with electromagnetic probes. Two projects are underway to attempt the detection of gravitational waves: NASA's Laser Interferometer Space Antenna (LISA), a space based mission being designed to search for waves from supermassive black holes at the centers of galaxies, and the NSF's Laser Interferometer Gravitational Wave Observatory (LIGO), a ground based facility that is now searching for waves from supernovae. pulsars, and the coalescence of black hole and neutron star systems. Because general relativity is an inherently non-linear theory, many of the predicted source waveforms show strong frequency modulation. In addition, the LIGO and LISA detectors are highly sensitive devices that produce a variety of non-linear transient noise features. Thus the unique capabilities of the HHT. the extraction of intrawave modulation and the characterization of non-linear and non-stationary signals, have a natural application to both signal detection and experimental characterization of the detectors. In this talk I will give an overview of the status of the field. including some of the expected sources of gravitational waves, and I will also describe the LISA and LIGO detectors. Then I will describe some applications of the HHT to waveform detection and detector noise characterization.

Camp, Jordan↗
DOE OSTI2018

Progress in the Physisorption Characterization of Nanoporous Gas Storage Materials

Assessing the adsorption properties of nanoporous materials and determining their structural characterization is critical for progressing the use of such materials for many applications, including gas storage. Gas adsorption can be used for this characterization because it assesses a broad range of pore sizes, from micropore to mesopore. In the past 20 years, key developments have been achieved both in the knowledge of the adsorption and phase behavior of fluids in ordered nanoporous materials and in the creation and advancement of state-of-the-art approaches based on statistical mechanics, such as molecular simulation and density functional theory. Together with high-resolution experimental procedures for the adsorption of subcritical and supercritical fluids, this has led to significant advances in physical adsorption textural characterization. In this short, selective review paper, we discuss a few important and central features of the underlying adsorption mechanisms of fluids in a variety of nanoporous materials with well-defined pore structure. In conclusion, the significance of these features for advancing physical adsorption characterization and gas storage applications is also discussed.

42 ENGINEERING↗