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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 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Physical Background, Computations and Practical Issues of the Magnetohydrodynamic Pressure Drop in a Fusion Liquid Metal Blanket

In blankets of a fusion power reactor, liquid metal (LM) breeders, such as pure lithium or lead-lithium alloy, circulate in complex shape blanket conduits for power conversion and tritium breeding in the presence of a strong plasma-confining magnetic field. The interaction of the magnetic field with induced electric currents in the breeder results in various magnetohydrodynamic (MHD) effects on the flow. Of them, high MHD pressure losses in the LM breeder flows is one of the most important feasibility issues. To design new feasible LM breeding blankets or to improve the existing blanket concepts and designs, one needs to identify and characterize sources of high MHD pressure drop, to understand the underlying physics of MHD flows and to eventually define ways of mitigating high MHD pressure drop in the entire blanket and its sub-components. This article is a comprehensive review of earlier and recent studies of MHD pressure drop in LM blankets with a special focus on: (1) physics of LM MHD flows in typical blanket configurations, (2) development and testing of computational tools for LM MHD flows, (3) practical aspects associated with pumping of a conducting liquid breeder through a strong magnetic field, and (4) approaches to mitigation of the MHD pressure drop in a LM blanket.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2024

Online Monitoring of Catalytic Processes by Fiber-Enhanced Raman Spectroscopy

An innovative solution for real-time monitoring of reactions within confined spaces, optimized for Raman spectroscopy applications, is presented. This approach involves the utilization of a hollow-core waveguide configured as a compact flow cell, serving both as a conduit for Raman excitation and scattering and seamlessly integrating into the effluent stream of a cracking catalytic reactor. The analytical technique, encompassing device and optical design, ensures robustness, compactness, and cost-effectiveness for implementation into process facilities. Notably, the modularity of the approach empowers customization for diverse gas monitoring needs, as it readily adapts to the specific requirements of various sensing scenarios. As a proof of concept, the efficacy of a spectroscopic approach is shown by monitoring two catalytic processes: CO 2 methanation (CO 2 + 4H 2 → CH 4 + 2H 2 O) and ammonia cracking (2NH 3 → N 2 + 3H 2 ). Leveraging chemometric data processing techniques, spectral signatures of the individual components involved in these reactions are effectively disentangled and the results are compared to mass spectrometry data. This robust methodology underscores the versatility and reliability of this monitoring system in complex chemical environments.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Point-scale organic-matter decomposition in streambeds is weakly associated with reach-scale respiration

Stream and river ecosystems play a central role in the movement and decomposition of particulate organic matter, serving as a conduit between terrestrial hillslopes and coastal environments. Microbial-catalyzed decomposition generates simpler organic molecules that fuel respiration, often in the sediments of these ecosystems. However, the degree of connection between sediment-associated respiration (ER??d) and organic-matter decomposition remains poorly understood. How that relationship compares to decomposition’s relationship with whole ecosystem (ERtot) and water column (ERwc) respiration is also not clear. We examined the link between particulate organic matter decomposition—using cellulose-based cotton strips as a standardized substrate—and all three components of respiration across 48 sites in the environmentally diverse Yakima River Basin (Washington State, USA). We hypothesized that decomposition within sediments would be most strongly related to ERsed, but decomposition rates were more closely associated with ERtot, with little connection to ERsed or ERwc. This suggests that particulate organic matter decomposition within stream/river sediments reflects integrated system respiration rather than processes confined to sediments or the water column alone. Further, across the basin, decomposition rates nearly spanned the previously reported global range for streams and rivers and were best explained by total dissolved nitrogen (TDN), sediment grain size, and aridity of the upstream drainage area. These results highlight the strong influence of land cover and basin-scale biophysical variation on sediment-associated decomposition processes and indicate that mechanistic models of organic matter decomposition in streams/rivers should account for coupled sediment–water–land interactions.

Stegen, James C. (ORCID:0000000191357424)↗
DOE OSTI2024

Novel sterol binding domains in bacteria

Sterol lipids are widely present in eukaryotes and play essential roles in signaling and modulating membrane fluidity. Although rare, some bacteria also produce sterols, but their function in bacteria is not known. Moreover, many more species, including pathogens and commensal microbes, acquire or modify sterols from eukaryotic hosts through poorly understood molecular mechanisms. The aerobic methanotroph Methylococcus capsulatus was the first bacterium shown to synthesize sterols, producing a mixture of C-4 methylated sterols that are distinct from those observed in eukaryotes. C-4 methylated sterols are synthesized in the cytosol and localized to the outer membrane, suggesting that a bacterial sterol transport machinery exists. Until now, the identity of such machinery remained a mystery. In this study, we identified three novel proteins that may be the first examples of transporters for bacterial sterol lipids. The proteins, which all belong to well-studied families of bacterial metabolite transporters, are predicted to reside in the inner membrane, periplasm, and outer membrane of M. capsulatus, and may work as a conduit to move modified sterols to the outer membrane. Quantitative analysis of ligand binding revealed their remarkable specificity for 4-methylsterols, and crystallographic structures coupled with docking and molecular dynamics simulations revealed the structural bases for substrate binding by two of the putative transporters. Their striking structural divergence from eukaryotic sterol transporters signals that they form a distinct sterol transport system within the bacterial domain. Finally, bioinformatics revealed the widespread presence of similar transporters in bacterial genomes, including in some pathogens that use host sterol lipids to construct their cell envelopes. The unique folds of these bacterial sterol binding proteins should now guide the discovery of other proteins that handle this essential metabolite.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Acoustic MEMS Sensor Array for Quench Detection of CICC Superconducting Cables

A novel quench detection method using microelectro- mechanical system (MEMS) sensor technology has been investigated in use for high temperature superconducting (HTS) conductors such REBCO tape cables. The sensor array along a superconducting cable, such as a cable-in-conduit-conductor (CICC), is installed in a cooling channel. It will allow sensitive and quick detection for a local quench of a superconducting cable. This work has confirmed that a quench of a single REBCO tape can be detected in liquid nitrogen by a MEMS piezoelectric microphone sensor. The quench detection design utilizing a MEMS sensor array method is discussed for the case of a toroidal field (TF) magnets of a fusion Tokamak device.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

An Acoustic Quench Detection Method for CICC Conductor Operating in Gas or Liquid

A method using micro-electro-mechanical system (MEMS) acoustic sensor technology to detect a quench and abnormal behavior of a superconductor is discussed. MEMS of microphone chips are installed along the coolant space of a superconducting conductor to monitor the coolant condition. By arranging the acoustic sensor array in a coolant flow channel, it is possible to quickly detect a change in the local condition of the coolant with precise spatial resolution. This method is useful for monitoring superconducting magnets and power cables, especially those made with a cable-in-conduit-conductor (CICC) configuration. The methodology described in this work will also be very useful for a high temperature superconducting (HTS) conductor, such as REBCO tape conductors.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
NASA NTRS1966

Metal tube can be folded for compact stowage, is self-erecting

Metal tube configuration reduces the section modulus to that of a thin plate, thus permitting the section to be bent into a coil for stowage in limited space without destructive yielding of the material. It is readily released to serve as a rigid fluid transportation conduit or structural member.

Source record↗
NASA NTRS1968

Multichannel wireway adapter box

Adapter box provides continuous separation of different electrical leads at points where their runs must intersect. Thus, multichannel conduits of standard commercial design may be used in a manner that prevents crossing of wire leads carrying different currents where the runs intersect and change direction.

Blake, W.↗
NASA NTRS1969

Hydraulic calipers

Hydraulic calipers determine area of annular openings in irregular or concealed passages. With modifications the device could be adapted to investigations of cross-sectional changes in heat flow passages, ducts, conduits, and heat exchanger elements.

Benson, J. A.↗
NASA NTRS1972

Low noise electromagnetic flowmeter

Parasitic hum is removed by using an isophase magnetic field created within flowmeter and an enclosure which prevents leakage of flux field. Method prevents contamination of flow conduit and eliminates zero point drift.

Cushing, V. J.↗
NASA NTRS1971

Fire retardancy using applied materials

An example of advanced technology transfer from the Little Joe, Surveyor, Comsat, re-entry and Apollo age to everyday fire protection needs is presented. Utilizing the principle of sublimation cooling for thermostatic temperature control, the material meets a wide range of fire retardancy and heat transmission control requirements. Properties vary from flexible tape for conduits and electrical cables to rigid coatings for column protection, with a broad spectrum of sublimation temperatures available. The material can be applied in the field or in the factory, utilizing mass production techniques, yielding a product that is reliable, effective, widely available and low in cost.

Feldman, R.↗
NASA NTRS1971

Technology for the cities

The activities of an organization for making the technology derived from NASA programs available for use by urban communities are discussed. Examples of technology utilization accomplished by the organization are: (1) self-contained breathing apparatus for firemen, (2) short range communication systems, (3) pavement marking, (4) protective clothing for firemen, (5) underground pipe and conduit locator, and (6) automatic fire hose flow regulator. The manner in which urban problems are identified and the designation of applicable technical developments are described.

Source record↗
NASA NTRS1973

Identification and interpretation of tectonic features from ERTS-1 imagery

The author has identified the following significant results. The spatial relation of mercury deposits and faults in California coast ranges suggests regional structural control whereby the transverse faults and associated zones of weakness provided easy conduits for the ascent of hydrothermal solutions and emplacement of mercury ore. If proved valid, this relation identifies transverse fault zones as favorable structural guides for mercury exploration.

Abdel-Gawad, M.↗