Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Vacuum Vessel”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS2013

Microgravity Storage Vessels and Conveying-Line Feeders for Cohesive Regolith

Under microgravity, the usual methods of placing granular solids into, or extracting them from, containers or storage vessels will not function. Alternative methods are required to provide a motive force to move the material. New configurations for microgravity regolith storage vessels that do not resemble terrestrial silos, hoppers, or tanks are proposed. The microgravity-compatible bulk-material storage vessels and exit feed configurations are designed to reliably empty and feed cohesive material to transfer vessels or conveying ducts or lines without gravity. A controllable motive force drives the cohesive material to the exit opening(s), and provides a reliable means to empty storage vessels and/or to feed microgravity conveying lines. The proposed designs will function equally well in vacuum, or inside of pressurized enclosures. Typical terrestrial granular solids handling and storage equipment will not function under microgravity, since almost all such equipment relies on gravity to at least move material to an exit location or to place it in the bottom of a container. Under microgravity, there effectively are no directions of up or down, and in order to effect movement of material, some other motive force must be applied to the material. The proposed storage vessels utilize dynamic centrifugal force to effect movement of regolith whenever material needs to be removed from the storage vessel. During simple storage, no dynamic motion or forces are required. The rotation rate during emptying can be controlled to ensure that material will move to the desired exit opening, even if the material is highly cohesive, or has acquired an electrostatic charge. The general concept of this Swirl Action Utilized for Centrifugal Ejection of Regolith (SAUCER) microgravity storage unit/dynamic feeder is to have an effective slot-hopper (based on the converging angles of the top and bottom conical section of the vessel) with an exit slot around the entire periphery of the SAUCER. The basic shape of such a unit is like two Chinese straw hats (douli) - one upside down, on the bottom, and another on top; or two wokpans, one upright on the bottom and another inverted on top, with a small gap between the upright and inverted pans or hats (around the periphery). A stationary outer ring, much like an unmounted bicycle tire, surrounds the gap between the two coaxial, nearly conical pieces, forming the top and bottom of the unit.

Walton, Otis R.↗
NASA NTRS2015

Simplified Methodology to Estimate the Maximum Liquid Helium (LHe) Cryostat Pressure from a Vacuum Jacket Failure

The aircraft-based Stratospheric Observatory for Infrared Astronomy (SOFIA) is a platform for multiple infrared astronomical observation experiments. These experiments carry sensors cooled to liquid helium temperatures. The liquid helium supply is contained in large (i.e., 10 liters or more) vacuum-insulated dewars. Should the dewar vacuum insulation fail, the inrushing air will condense and freeze on the dewar wall, resulting in a large heat flux on the dewar's contents. The heat flux results in a rise in pressure and the actuation of the dewar pressure relief system. A previous NASA Engineering and Safety Center (NESC) assessment provided recommendations for the wall heat flux that would be expected from a loss of vacuum and detailed an appropriate method to use in calculating the maximum pressure that would occur in a loss of vacuum event. This method involved building a detailed supercritical helium compressible flow thermal/fluid model of the vent stack and exercising the model over the appropriate range of parameters. The experimenters designing science instruments for SOFIA are not experts in compressible supercritical flows and do not generally have access to the thermal/fluid modeling packages that are required to build detailed models of the vent stacks. Therefore, the SOFIA Program engaged the NESC to develop a simplified methodology to estimate the maximum pressure in a liquid helium dewar after the loss of vacuum insulation. The method would allow the university-based science instrument development teams to conservatively determine the cryostat's vent neck sizing during preliminary design of new SOFIA Science Instruments. This report details the development of the simplified method, the method itself, and the limits of its applicability. The simplified methodology provides an estimate of the dewar pressure after a loss of vacuum insulation that can be used for the initial design of the liquid helium dewar vent stacks. However, since it is not an exact tool, final verification of the dewar pressure vessel design requires a complete, detailed real fluid compressible flow model of the vent stack. The wall heat flux resulting from a loss of vacuum insulation increases the dewar pressure, which actuates the pressure relief mechanism and results in high-speed flow through the dewar vent stack. At high pressures, the flow can be choked at the vent stack inlet, at the exit, or at an intermediate transition or restriction. During previous SOFIA analyses, it was observed that there was generally a readily identifiable section of the vent stack that would limit the flow – e.g., a small diameter entrance or an orifice. It was also found that when the supercritical helium was approximated as an ideal gas at the dewar condition, the calculated mass flow rate based on choking at the limiting entrance or transition was less than the mass flow rate calculated using the detailed real fluid model2. Using this lower mass flow rate would yield a conservative prediction of the dewar’s wall heat flux capability. The simplified method of the current work was developed by building on this observation.

Ungar, Eugene K.↗
DOE OSTI2023

Quantitative Measurement of Positive and Negative Ion Species Ejected from a Li–O–H Surface by Hydrogen and Noble Gas Ion Irradiation

We report sputtering yields of Li + , H - , O - , and OH x - ion species from an Li–O–H surface for H, D, He, Ne, and Ar ion irradiation at 45° incidence in the energy range of 30–2000 eV. A Li film was deposited on a stainless steel target using Li evaporators in the LTX-β vessel, using the LTX-β Sample Exposure Probe (SEP), which includes an ultrahigh vacuum suitcase for transferring targets without significant contamination from air exposure. The SEP was used to transfer the Li-coated target from LTX-β to a separate Sample Exposure Station (SES) to perform ion exposure measurements. The SEP was also used for characterization of the Li-coated target utilizing X-ray photoelectron spectroscopy in a different chamber, showing that the lithium film surface was oxidized. Ion exposures were performed using an electron cyclotron resonance plasma source in the SES. Sputtered/ejected species were sampled by a quadrupole mass spectrometer with capabilities for detecting positive and negative ions, and an energy filter for determining the mean kinetic energy of the ejected ion species. All ion irradiations caused Li + ions to be ejected, while causing impurity ions such as H + , H - , O - and OH - to be ejected. Measured ion energies of Li + ions from a Li–O–H surface suggested that the typical sheath potential on the divertor surface can trap sputtered Li + ions, which were previously reported as ~ 60% of total sputtered Li species from Li targets (Allain and Ruzic in Nucl Fusion 42:202, 2002). Hence, our results for the sputtering yields of ejected ion species and their associated ion energies from a Li–O–H surface indicates that lithium sputtering is suppressed and impurity removal is enhanced due to the sheath potential at the divertor surface for fusion reactor applications.

Plasma-material interaction↗
NASA NTRS2009

Gratings Fabricated on Flat Surfaces and Reproduced on Non-Flat Substrates

A method has been developed for fabricating gratings on flat substrates, and then reproducing the groove pattern on a curved (concave or convex) substrate and a corresponding grating device. First, surface relief diffraction grating grooves are formed on flat substrates. For example, they may be fabricated using photolithography and reactive ion etching, maskless lithography, holography, or mechanical ruling. Then, an imprint of the grating is made on a deformable substrate, such as plastic, polymer, or other materials using thermoforming, hot or cold embossing, or other methods. Interim stamps using electroforming, or other methods, may be produced for the imprinting process or if the same polarity of the grating image is required. The imprinted, deformable substrate is then attached to a curved, rigid substrate using epoxy or other suitable adhesives. The imprinted surface is facing away from the curved rigid substrate. As an alternative fabrication method, after grating is imprinted on the deformable substrate as described above, the grating may be coated with thin conformal conductive layer (for example, using vacuum deposition of gold). Then the membrane may be mounted over an opening in a pressured vessel in a manner of a membrane on a drum, grating side out. The pressure inside of the vessel may be changed with respect to the ambient pressure to produce concave or convex membrane surface. The shape of the opening may control the type of the surface curvature (for example, a circular opening would create spherical surface, oval opening would create toroidal surface, etc.). After that, well-known electroforming methods may be used to create a replica of the grating on the concave or convex membrane. For example, the pressure vessel assembly may be submerged into an electro-forming solution and negative electric potential applied to the metal coated membrane using an insulated wire. Positive electric potential may be then applied to a nickel or other metal plate submerged into the same solution. Metal ions would transfer from the plate through the solution into the membrane, producing high fidelity metal replica of the grating on the membrane. In one variation, an adhesive may be deposited on the deformable substrate, and then cured without touching the rigid, curved substrate. Edges of the deformable substrate may be attached to the rigid substrate to ensure uniform deformation of the deformable substrate. The assembly may be performed in vacuum, and then taken out to atmospheric pressure conditions to ensure that no air is trapped between the deformable and rigid substrates. Alternatively, a rigid surface with complementary curvature to the rigid substrate may be used to ensure uniform adhesion of the deformable substrate to the rigid substrate. Liquid may be applied to the surface of the deformable substrate to uniformly distribute pressure across its surface during the curing or hardening of the adhesive, or the film may be pressed into the surface using a deformable object or surface. After the attachment is complete, the grooves may be coated with reflective or dielectric layers to improve diffraction efficiency.

Content, David↗
DOE OSTI2025

Diagnostics: Chapter 8 of the special issue: on the path to tokamak burning plasma operation

This chapter presents the activity conducted by the ITPA topical group (TG) on Diagnostics over about the last 15 years. Following a general introduction of the ITER Diagnostics led by their measurement roles, the document is organized in several subchapters detailing the design support, research and development activity conducted by each of the specialist working groups (WGs) of the TG. Please note that the magnetic diagnostics were supported at the TG without a specific WG. Their status is included in the general introduction. In the following some highlights of the subchapter’s contents are provided. Recent advances in ITER first wall (FW) diagnostics for the measurements of plasma-metallic wall interaction in support of the ITER research plan are reported. An InfraRed imaging Video Bolometer for ITER has been developed and tested on several tokamaks to measure the radiated power loss. A laser-induced breakdown spectroscopy (LIBS) technique which utilizes a pulsed laser beam to ablate locally by forming a crater, will measure local tritium inventory in the FW material. Real-time Residual Gas Analyzers will measure the neutral gas composition in a divertor port and an equatorial port during plasma operation. Due to the full metallic FW environment, the plasma-wall interaction in ITER will face several challenges such as the compromised radiated power and divertor heat flux measurements by reflection. Ray tracing and analysis codes have been developed to eliminate and correct the effects of reflection in the measurements. The characteristics of the reflecting surfaces depending on the roughness and angle of the incidence have been measured by dedicated experiments, and the results were applied to the reflection elimination. For the measurement of the metallic impurity radiation induced by eroded metallic atoms, a vacuum ultraviolet spectrometer has been developed and tested. An extensive thermonuclear diagnostic suite will be required to support the operation of ITER and the planned experimental program for future burning plasma experiments. Due to the harsh environmental conditions, the implementation of diagnostic systems in ITER is a major challenge. These conditions include high levels of neutron and gamma fluxes, neutron heating, particle bombardment. Therefore, the selection and design of diagnostic systems must take into account a number of phenomena previously unseen in diagnostic design. For this reason, the measurement of neutrons and confined or lost fast ions, with particular emphasis on alpha particles, is critical to ITER. The diagnostics associated with these measurements will be important for future plasma-burning experiments at ITER. The high neutron emission and very large plasma size in ITER make neutron diagnostics the main diagnostic method used to measure plasma parameters such as fusion power, fusion power density, ion temperature, energy of fast ions and their spatial distributions in the plasma core. Active spectroscopy techniques are methods where a neutral particle beam is injected into the plasma and information on plasma parameters is extracted from the measurement of line emission resulting from the beam-plasma interaction, either by plasma ions or by beam atoms. Spatial localization is achieved by crossing the beamline and multiple observation lines. The ITER plasma will be a high temperature, moderately dense, fully ionized collisional plasma. The plasma facing surfaces are principally metallic being fashioned from beryllium or tungsten but many other elements, arising from either structural or from operational needs, may enter this plasma. The energy range of the emitted photons range from meV (infra-red) to multi keV (x-rays) and originate from all areas of the plasma volume. The primary role of passive emission diagnostics is to identify what is in the plasma from spectral signatures. Extracting quantitative information from these measurements such as impurity content, ion temperature, rotation, degree of detachment and radiated power depends on calibrated instruments, a physics model of the atomic and molecular processes and plasma transport and an analysis workflow that takes into account environmental effects such as reflections. The particular needs for ITER have prompted a multi-machine, many-year effort to address all these aspects and this chapter reviews the work on diagnostic design, experiments and new analysis techniques. An overview of the laser diagnostics to be implemented on ITER is also provided in this paper. This includes descriptions of the Thomson scattering in the core, edge and divertor regions, polarimetry and interferometry diagnostics used for measuring plasma density and also measurements of helium density in the divertor using Laser Induced Flourescence. Techniques which can allow improvements on current measurements are also addressed in particular expanding poloidal polarimetry measurements to measure field fluctuations and proposed use of dispersion interferometery which has a number of advantages over existing methods. This paper identifies particular areas where further research and testing on existing tokamaks is useful even at this advanced stage to inform the design of diagnostics for ITER. Outstanding areas of concern for the implementation of laser diagnostics, in particular with a view to reliable operation are identified. An overview of the latest developments of microwave diagnostic systems and techniques is given. The primary focus is the contributions for ITER—the next step burning plasma experiment—which is supplemented by describing recent progress of techniques applicable for fusion experiments beyond ITER. The contributions are intentionally kept concise, and are being supplemented by a rich list of references for further studies. Radiation induced effects are receiving continuous and well-deserved attention of the ITER diagnostic community and they are in many cases one of the primary design drivers of the ITER diagnostic systems. The paper summarizes recent progress in this area focusing primarily on the ITER diagnostics but in some cases provides also outlook for the possible solutions for even more demanding radiation environment of fusion reactors beyond ITER. Despite advancements in the area of modeling and simulation of various radiation induced effects, experimental testing in a nuclear environment as close as possible to the target one is still seen as unavoidable for proper qualification of particular diagnostic functional elements. Recent advancement within three diagnostic areas: optical diagnostics, magnetics and bolometers is covered. Encouraging results on qualification of silica glass vacuum window assemblies are presented. In the area of magnetic sensors, progress of irradiation tests performed on ITER in-vessel LTCC inductive sensors is presented with outlook for novel technological approaches to inductive sensors utilizing thick printing and photolithography technologies being highlighted. Summary of advancements in the area of steady state magnetic field sensors based on Hall effect is given. New results of neutron irradiation test of the ITER borosilicate glass inserts for vacuum electrical feedthroughs are summarized finding negligible swelling at target level of neutron fluence. Off-line irradiation tests of fiber optic current sensors for plasma current measurement demonstrated that both for gamma doses up to 5 MGy and a total neutron fluence up to 10 15 cm −2 , radiation induced changes are still compatible with required measurement accuracy on ITER. The ITER bolometers are given as an example how considering radiation effects may influence the diagnostic design. Finally, outlook for future main R&D directions is outlined. All optical and laser-based diagnostics in ITER will be using mirrors to guide plasma radiation toward detectors, cameras and sensors. In the hostile plasma, radiation and particle environment the optical characteristics of diagnostic mirrors will degrade directly affecting the entire performance of involved diagnostic systems. An assessment of factors affecting mirror performance is provided. Among the prime adverse factors are deposition of plasma impurities, sputtering of mirror surface and steam ingress in the vicinity of mirrors. Within the International Tokamak Physics Activity with active support by ITER central team and domestic agencies, the structured research and development (R&D) program on mitigation of risks for diagnostic mirrors is underway. Within this program the mirror material development, the passive mitigation of mirror degradation by using diagnostic ducts and shutters along with an active mirror recovery program comprising the in-situ mirror cleaning and calibration is underway. Recent developments in diagnostic mirror R&D are described in this Chapter along with an example of their implementation of R&D solutions in ITER Infrared Thermography diagnostic. An assessment of still open engineering and physics questions, considerations on mirror risks during an early phase of ITER operation are given along with an overview of diagnostic mirror evolution in the late ITER operation stage toward the demonstration fusion power plant. Several crucial areas of diagnostic R&D outlined in ITER Research Plan are addressed. The basic control groups in a fusion reactor can be broken-down in five categories: (1) plasma position, magnetic configuration, and plasma current control, (2) profile control and confinement optimization, (3) MHD control and suppression, (4) edge dissipation control, radiation and plasma exhaust control and (5) break-down optimization. These categories are coupled via the physics (a control action in one domain will affect the other domains) and via shared actuators (e.g. ECRH for impurity accumulation avoidance, current density distribution control and MHD suppression). Consequently, a supervisory control system should determine the priority of the various control tasks, their couplings, and the interfaces with the safety and interlock system. For the systematic development of the various controllers taking the complexity of the plasma and the control system into account, a model-based approach is required. A short historical overview is given of the developments in systems and control theory and control engineering with special emphasis on those developments that are most relevant for Nuclear Fusion research and operation. An overview is given of the state of the field of fusion plasma control for the control categories. It will be shown how synthetic diagnostics are being developed in ITER and how they are used in diagnostic design and design validation and how they can be in model-based controller synthesis using relatively simple models. In modern control methods, multiple diagnostics are used to constrain relatively simple models. The constrained models provide an estimate for the state. This opens the route to state controllers, such as model predictive control. A major challenge in nuclear fusion research is the coherent combination of data from heterogeneous diagnostics and modeling codes for machine control and safety as well as physics studies. Measured data from different diagnostics often provide information about the same subset of physical parameters. Additionally, information provided by some diagnostics might be needed for the analysis of other diagnostics. A joint analysis of complementary and redundant data allows, e.g. to improve the reliability of parameter estimation, to increase the spatial and temporal resolution of profiles, to obtain synergistic effects, to consider diagnostics interdependencies and to find and resolve data inconsistencies. Physics-based modeling and parameter relationships provide additional information improving the treatment of ill-posed inversion problems. A coherent combination of all kind of available information within a probabilistic framework allows for improved data analysis results. The concept of integrated data analysis (IDA) in the framework of Bayesian probability theory is outlined and contrasted with conventional data analysis. Components of the probabilistic approach are summarized and specific ingredients beneficial for data analysis at fusion devices are discussed.

ITER↗
NASA NTRS1983

Terrestrial whisker growth experiments which anticipate some special effects of a space station environment

The effects of the absence of gravitationally driven thermal convection on the growth of whiskers by chemical reduction of metal salts was studied. It was possible to accomplish nearly complete suppression of such convection. Suppression of the convection does indeed effect the growth but in subtle, not necessarily detrimental ways: none of the changes observed were such as to hamper efforts to produce whiskers in space. Copper whiskers grown from cuprous iodide respond most positively to the suppression of convection; therefore, they are strongly recommended for tests in the space environment. Cobalt whiskers grown from cobaltous bromide show the greatest independence from conditions of convection and applied electric fields of any material studied; therefore, this medium is highly recommended. A strong pulse of electric field forces the whiskers to stick to the growth vessel top plate, this facilitates study or "harvesting'. On the space station it is recommended that the growth vessels be mounted outside the laboratory and joined with the station by means of double vacuum valves and gas service lines.

Hobbs, H. H.↗
NASA NTRS1995

Inflatable structures for a lunar base

The first step in the human expansion into space consists of the construction of a human-tended base on the Moon. Establishment of a lunar base depends upon the development of a structure capable of accomodating human life and activities in a shirt sleeve environment. Design and construction of a structure on the Moon require addressing a host of issues and loads that are not encountered on Earth. A lunar structure is essentially a pressure vessel since the internal pressure is the dominating load. The external pressure is effectively an absolute vacuum and the dead loads from both the material mass and a protective regolith layer are quite small due to low lunar gravity. An inflatable structure made of a thin membrane integrated with an inflated supporting frame is highly efficient in resisting the internal pressure loading and the dead loads. Preliminary design computations for a generic lunar inflatable structure are presented.

Sadeh, Willy Z.↗
NASA NTRS1977

External heater for cryogenic vessels

When used in conjunction with nitrogen purge system, external heating film increases gas temperature, thereby preventing chilling of equipment. Proposed system includes vacuum-deposited layer of gold sandwiched between two layers of Mylar, which act as carrier for film and prevent damage.

Wennagel, G. J.↗
NASA NTRS1984

A redetermination of the succinonitrile-water phase diagram

The phase diagram of the water/succinonitrile system often used in modeling binary metallic alloys is determined experimentally using a laser scattering method. Triply distilled and zone-refined succinonitrile is placed in a jacketed water-cooled vessel with a magnetic mixer and a copper-constantan thermocouple, and the melting point is determined under vacuum and under Ar by observing the response of a photodiode placed opposite a laser source as the chamber is cooled and reheated. Then water is added, and the eutectic and monotectic temperatures and the entire phase diagram are determined under Ar. The results are presented in a table and graph and compared to those of Schreinemakers (1897): significant discrepancies are noted and attributed to impurities in the succinonitrile used by Schreinemakers. The importance of accurate phase diagrams for modeling binary alloys is stressed.

Smith, J. E., Jr.↗
DOE OSTI2022

Application Of The ASME Boiler And Pressure Vessel Code In The Design Of SSR Cryomodule Beamlines For PIP-II Project At Fermilab

This contribution reports the design of the main components used to interconnect SRF cavities and superconducting focusing lenses in the SSR Cryomodule beamlines, developed in the framework of the PIP-II project at Fermilab. The focus of the present contribution is on the design and testing of the edge-welded bellows according to ASME Boiler and Pressure Vessel Code. The activities performed to qualify the bellows to be assembled in cleanroom, for operation in high vacuum, cryogenic environments, and their characterization from magnetic standpoint, will also be presented.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

Monte Carlo Analysis of the Performance of the ITER Diagnostic Residual Gas Analyzer

The composition of exhausted gas is a key parameter in long-pulse plasma fusion experiments, and its evolution shall be monitored at timescales relevant to plasma dynamics and plasma-wall interactions. A diagnostic residual gas analyzer (DRGA) is a multisensor instrument particularly suited to these studies, and ITER will adopt DRGAs in the equatorial and in the divertor tokamak regions. In this work, we have revisited the design of the ITER divertor DRGA through simple vacuum analytical considerations supported by simulations conducted with Molflow+, a test particle Monte Carlo (TPMC) simulation code commonly used in the particle accelerator community. Here, starting with recommendations on the manufacturing of the vacuum piping of the DRGA, this work is followed by a complete vacuum characterization of the diagnostic vacuum setup (pressure profiles at base pressure and during sampling, orifice diameter, and length optimization), and finally, the in-vessel residence time of the most important gas species is simulated. These studies have allowed us to give insights into some experimental results recently found on the prototype DRGA installed in the Wendelstein W7-X stellarator.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS1990

Spacecraft attitude impacts on COLD-SAT non-vacuum jacketed LH2 supply tank thermal performance

The Cryogenic On-Orbit Liquid Depot - Storage, Acquisition and Transfer (COLD-SAT) spacecraft will be launched into low earth orbit to perform fluid management experiments on the behavior of subcritical liquid hydrogen (LH2). For determining the optimum on-orbit attitude for the COLD-SAT satellite, a comparative analytical study was performed to determine the thermal impacts of spacecraft attitude on the performance of the COLD-SAT non-vacuum jacketed LH2 supply tank. Tank thermal performance was quantified by total conductive and radiative heat leakage into the pressure vessel due to the absorbed solar, earth albedo and infra-red on-orbit fluxes, and also by the uniformity of the variation of this leakage on the vessel surface area. Geometric and thermal analysis math models were developed for the spacecraft and the tank as part of this analysis, based on their individual thermal/structural designs. Two quasi-inertial spacecraft attitudes were investigated and their effects on the tank performance compared. The results are one of the criteria by which the spacecraft orientation in orbit was selected for the in-house NASA Lewis Research Center design.

Arif, Hugh↗
NASA NTRS1990

Spacecraft attitude impacts on COLD-SAT non-vacuum jacketed LH2 supply tank thermal performance

The Cryogenic On-Orbit Liquid Depot - Storage, Acquisition and Transfer (COLD-SAT) spacecraft will be launched into low earth orbit to perform fluid management experiments on the behavior of subcritical liquid hydrogen (LH2). For determining the optimum on-orbit attitude for the COLD-SAT satellite, a comparative analytical study was performed to determine the thermal impacts of spacecraft attitude on the performance of the COLD-SAT non-vacuum jacketed LH2 supply tank. Tank thermal performance was quantitied by total conductive and radiative heat leakage into the pressure vessel due to the absorbed solar, earth albedo and infra-red on-orbit fluxes, and also by the uniformity of the variation of this leakage on the vessel surface area. Geometric and thermal analysis math models were developed for the spacecraft and the tank as part of this analysis, based on their individual thermal/structural designs. Two quasi-inertial spacecraft attitudes were investigated and their effects on the tank performance compared. The results are one of the criteria by which the spacecraft orientation in orbit was selected for the in-house NASA Lewis Research Center design.

Arif, Hugh↗
NASA NTRS2016

Levitation Technology in International Space Station Research

The International Space Station (ISS) is a unique multidisciplinary orbiting laboratory for science and technology research, enabling discoveries that benefit life on Earth and exploration of the universe. ISS facilities for containerless sample processing in Materials Science experiments include levitation devices with specimen positioning control while reducing containment vessel contamination. For example, ESA's EML (ElectroMagnetic Levitator), is used for melting and solidification of conductive metals, alloys, or semiconductors in ultra-high vacuum, or in high-purity gaseous atmospheres. Sample heating and positioning are accomplished through electromagnetic fields generated by a coil system. EML applications cover investigation of solidification and microstructural formation, evaluation of thermophysical properties of highly reactive metals (whose properties can be very sensitive to contamination), and examination of undercooled liquid metals to understand metastable phase convection and influence convection on structural changes. MSL utilization includes development of novel light-weight, high-performance materials. Another facility, JAXA's ELF (Electrostatic Levitation Furnace), is used to perform high temperature melting while avoiding chemical reactions with crucibles by levitating a sample through Coulomb force. ELF is capable of measuring density, surface tension, and viscosity of samples at high temperatures. One of the initial ELF investigations, Interfacial Energy-1, is aimed at clarification of interfacial phenomena between molten steels and oxide melts with industrial applications in control processes for liquid mixing. In addition to these Materials Science facilities, other ISS investigations that involve levitation employ it for biological research. For example, NASA's "Magnetic 3D Culturing and Bioprinting" investigation uses magnetic levitation for three-dimensional culturing and positioning of magnetized cells to generate spheroid assemblies for biomedical applications. Levitation is also used as a modeled microgravity ground analog in the NASA OsteoOmics ISS investigation, which tests whether magnetic levitation accurately simulates microgravity conditions by studying gravitational regulation of osteoblast and osteoclast genomics and metabolism. Elucidating the cellular mechanisms of bone loss in microgravity contributes to the understanding of bone loss in medical disorders on Earth, which may lead to development of preventive or therapeutic countermeasures. Thus, the ISS state-of-the-art laboratory offers various levitation capability platforms with applications for innovative research in Materials and Life Sciences disciplines, with benefits for humanity.

Guinart-Ramirez, Y.↗
DOE OSTI2025

Design and Engineering of LUPIN: A Test-Bed Radio-Frequency Ion Source for Enhanced Neutral Beam Injection on DIII-D

The Large, Uniform Plasma for Ionizing Neutrals (LUPIN) is a radio-frequency (RF) inductively coupled plasma (ICP) chamber for demonstrating plasma performance of an RF ICP positive ion source upgrade for the DIII-D neutral beam injection (NBI) system. LUPIN will be used to investigate ion source physics, including neutral gas dynamics, plasma density uniformity, interactions with Faraday shields, and power coupling to novel RF antenna designs. LUPIN has an RF generator capable of delivering 20 kW of power at 2 MHz, which is coupled into a cylindrical quartz vessel measuring 20 cm in length and 10 cm in radius. This configuration matches the power density requirements for a full-scale ion source. Target hydrogen and deuterium plasma densities exceeding 10 18 m -3 would relate to extracted ion current densities of 2100 A/m 2 for 10s. Vacuum conductance and gas flow calculations predict a maximum achievable neutral gas flow rate of 1675 Pa ⋅ L/s at 5 Pa of He, which mimics the gas flow of the DIII-D NBI system. Designs have been developed for an internal Faraday shield to mitigate heat flux and ion sputtering on the dielectric vessel. Thermomechanical finite element simulations demonstrated the Faraday shield design to be capable of withstanding anticipated heat loads from worst-case operation scenarios. Finally, results of upcoming experimental investigations on LUPIN will guide the design of a full-scale prototype for DIII-D integration.

Faraday shield↗
DOE OSTI2024

Design and Engineering of LUPIN: A Test-Bed Radiofrequency Ion Source for Enhanced Neutral Beam Injection on DIII-D

The Large, Uniform Plasma for Ionizing Neutrals (LUPIN) is an RF inductively coupled plasma (ICP) chamber for demonstrating plasma performance of an RF ICP positive ion source upgrade for the DIII-D Neutral Beam Injection (NBI) system. LUPIN will be used to investigate ion source physics, including neutral gas dynamics, plasma density uniformity, interactions with Faraday shields, and power coupling to novel RF antenna designs. LUPIN has an RF generator capable of delivering 20 kW of power at 2 MHz, which is coupled into a cylindrical quartz vessel measuring 20 cm in length and 10 cm in radius. This configuration matches the power density requirements for a full-scale ion source. Target hydrogen and deuterium plasma densities exceeding 10 18 m -3 would relate to extracted ion current densities of 2100 A/m 2 for 10 s. Vacuum conductance and gas flow calculations predict a maximum achievable neutral gas flow rate of 1675 Pa·L/s at 5 Pa of He, which mimics the gas flow of the DIII-D NBI system. Designs have been developed for an internal Faraday shield to mitigate heat flux and ion sputtering on the dielectric vessel. Thermomechanical finite element simulations demonstrated the Faraday shield design to be capable of withstanding anticipated heat loads from worst-case operation scenarios. Results of upcoming experimental investigations on LUPIN will guide the design of a full-scale prototype for DIII-D integration.

Faraday shield↗
NASA NTRS2010

NASA Tech Briefs, January 2010

Topics covered include: Cryogenic Flow Sensor; Multi-Sensor Mud Detection; Gas Flow Detection System; Mapping Capacitive Coupling Among Pixels in a Sensor Array; Fiber-Based Laser Transmitter for Oxygen A-Band Spectroscopy and Remote Sensing; Low-Profile, Dual-Wavelength, Dual-Polarized Antenna; Time-Separating Heating and Sensor Functions of Thermistors in Precision Thermal Control Applications; Cellular Reflectarray Antenna; A One-Dimensional Synthetic-Aperture Microwave Radiometer; Electrical Switching of Perovskite Thin-Film Resistors; Two-Dimensional Synthetic-Aperture Radiometer; Ethernet-Enabled Power and Communication Module for Embedded Processors; Electrically Variable Resistive Memory Devices; Improved Attachment in a Hybrid Inflatable Pressure Vessel; Electrostatic Separator for Beneficiation of Lunar Soil; Amorphous Rover; Space-Frame Antenna; Gear-Driven Turnbuckle Actuator; In-Situ Focusing Inside a Thermal Vacuum Chamber; Space-Frame Lunar Lander; Wider-Opening Dewar Flasks for Cryogenic Storage; Silicon Oxycarbide Aerogels for High-Temperature Thermal Insulation; Supercapacitor Electrolyte Solvents with Liquid Range Below -80 C; Designs and Materials for Better Coronagraph Occulting Masks; Fuel-Cell-Powered Vehicle with Hybrid Power Management; Fine-Water-Mist Multiple-Orientation-Discharge Fire Extinguisher; Fuel-Cell Water Separator; Turbulence and the Stabilization Principle; Improved Cloud Condensation Nucleus Spectrometer; Better Modeling of Electrostatic Discharge in an Insulator; Sub-Aperture Interferometers; Terahertz Mapping of Microstructure and Thickness Variations; Multiparallel Three-Dimensional Optical Microscopy; Stabilization of Phase of a Sinusoidal Signal Transmitted Over Optical Fiber; Vacuum-Compatible Wideband White Light and Laser Combiner Source System; Optical Tapers as White-Light WGM Resonators; EPR Imaging at a Few Megahertz Using SQUID Detectors; Reducing Field Distortion in Magnetic Resonance Imaging; Fluorogenic Cell-Based Biosensors for Monitoring Microbes; A Constant-Force Resistive Exercise Unit; GUI to Facilitate Research on Biological Damage from Radiation; On-Demand Urine Analyzer; More-Realistic Digital Modeling of a Human Body; and Advanced Liquid-Cooling Garment Using Highly Thermally Conductive Sheets.

Source record↗
NASA NTRS1994

System Measures Thermal Noise In A Microphone

Vacuum provides acoustic isolation from environment. System for measuring thermal noise of microphone and its preamplifier eliminates some sources of error found in older systems. Includes isolation vessel and exterior suspension, acting together, enables measurement of thermal noise under realistic conditions while providing superior vibrational and accoustical isolation. System yields more accurate measurements of thermal noise.

Zuckerwar, Allan J.↗