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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

N-oleoylethanolamide suppresses intimal hyperplasia after balloon injury in rats through AMPK/PPARα pathway

Highlights: • OEA alleviates intimal hyperplasia induced by balloon injury. • OEA suppresses VSMC proliferation and migration. • OEA modulats VSMC proliferation and migration partly through AMPK- PPARα pathway. Vascular smooth muscle cell (VSMC) proliferation and migration are crucial events in the pathological course of restenosis after percutaneous coronary intervention (PCI). N-oleoylethanolamide (OEA) is a bioactive lipid amide released upon dietary fat digestion with many reported actions. However, the effect of OEA on restenosis after vascular injury remains unknown. Here, we investigated the effects of OEA on intimal hyperplasia after balloon injury in vivo, its effect on VSMC proliferation and migration induced by platelet-derived growth factor (PDGF) stimulation in vitro, and the underlying mechanism underlying these effects. The results showed that OEA-treated rats displayed a significant reduction in neointima formation after balloon injury. In cultured VSMCs, treatment with OEA decreased cell proliferation and migration induced by PDGF. OEA treatment both in vivo and in vitro led to an increase in adenosine monophosphate-activated protein kinase (AMPK) phosphorylation and peroxisome proliferator-activated receptor alpha (PPARα), and a decrease in proliferating cell nuclear antigen (PCNA) and cyclinD1 expression. Pharmacological inhibition of AMPK and PPARα reversed the suppressive effects of OEA on VSMC proliferation and migration, suggesting that the suppressive effect of OEA on VSMC proliferation and migration is mediated through the activation of AMPK and PPARα. In conclusion, our present study demonstrated that OEA attenuated neointima formation in response to balloon injury by suppressing SMC proliferation and migration through an AMPK and PPARα-dependent mechanism. Our data suggests that OEA may be a potential therapeutic agent for restenosis after PCI.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

The First Detection of an Earthquake From a Balloon Using Its Acoustic Signature

Extreme temperature and pressure conditions on the surface of Venus present formidable technological challenges against performing ground-based seismology. Efficient coupling between the Venusian atmosphere and the solid planet theoretically allows the study of seismically generated acoustic waves using balloons in the upper atmosphere, where conditions are far more clement. However, earthquake detection from a balloon has never been demonstrated. We present the first detection of an earthquake from a balloon-borne microbarometer near Ridgecrest, CA in July 2019 and include a detailed analysis of the dependence of seismic infrasound, as measured from a balloon on earthquake source parameters, topography, and crustal and atmospheric structure. Our comprehensive analysis of seismo-acoustic phenomenology demonstrates that seismic activity is detectable from a high-altitude platform on Earth, and that Rayleigh wave-induced infrasound can be used to constrain subsurface velocities, paving the way for the detection and characterization of such signals on Venus.

58 GEOSCIENCES↗
DOE OSTI2017

High- β equilibrium and ballooning stability of the low aspect ratio CNT stellarator

In the paper, the existence and ballooning-stability of low aspect ratio stellarator equilibria is predicted for the Columbia Neutral Torus (CNT) with the aid of 3D numerical tools. In addition to having a low aspect ratio, CNT is characterized by a low magnetic field and small plasma volume. Also, highly overdense plasmas were recently heated in CNT by means of microwaves. These characteristics suggest that CNT might attain relatively high values of plasma beta and thus be of use in the experimental study of stellarator stability to high-beta instabilities such as ballooning modes. As a first step in that direction, here the ballooning stability limit is found numerically. Depending on the particular magnetic configuration we expect volume-averaged β limits in the range 0.9%–3.0%, and possibly higher, and observe indications of a second region of ballooning stability. As the aspect ratio is reduced, stability is found to increase in some configurations and decrease in others. Energy-balance estimates using stellarator scaling laws indicate that the lower β limit may be attainable with overdense heating at powers of 40 to 100 kW. The present study serves the additional purpose of testing VMEC and other stellarator codes at high values of β and at low aspect ratios. For this reason, the study was carried out both for free boundary, for maximum fidelity to experiment, as well as with a fixed boundary, as a numerical test.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2017

The two-dimensional kinetic ballooning theory for ion temperature gradient mode in tokamak

The two-dimensional (2D) kinetic ballooning theory is developed for the ion temperature gradient mode in an up-down symmetric equilibrium (illustrated via concentric circular magnetic surfaces). The ballooning transform converts the basic 2D linear gyro-kinetic equation into two equations: (1) the lowest order equation (ballooning equation) is an integral equation essentially the same as that reported by Dong et al., [Phys. Fluids B 4, 1867 (1992)] but has an undetermined Floquet phase variable, (2) the higher order equation for the rapid phase envelope is an ordinary differential equation in the same form as the 2D ballooning theory in a fluid model [Xie et al., Phys. Plasmas 23, 042514 (2016)]. The system is numerically solved by an iterative approach to obtain the (phase independent) eigen-value. The new results are compared here to the two earlier theories. We find a strongly modified up-down asymmetric mode structure, and non-trivial modifications to the eigen-value.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2023

Ballooning theory for micro-tearing mode in tokamak

This paper aims to investigate the impact of magnetic drift on the linear micro-tearing mode by using a kinetic approach to derive a reduced two-field eigen system in real space. Here, since the magnetic drift in real space has derivatives, it is more efficient to solve the mode equations in a Fourier-ballooning representation using the two-dimensional (2D) ballooning transform. The lowest-order eigen system in the Fourier-ballooning representation consists of two integral equations, which are numerically solved using the finite difference method for both eigenvalues and wave functions. The main results will be presented through graphical eigenvalue scans for each parameter. Furthermore, we present a graphical comparison between the predictions of the ballooning theory and GENE gyrokinetic code simulation in the pedestal region.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

Omnigenous stellarators with improved ideal and kinetic ballooning stability

Omnigenity is a property of a magnetic field which ensures confinement of trapped particles. It is a necessary requirement for any high-performance stellarator. After creating an omnigenous equilibrium, one must also ensure reduced transport resulting from kinetic and magnetohydrodynamic (MHD) instabilities. To this end, we leverage the GPU-accelerated DESC optimization suite, which is used to design stable, finite-β omnigenous equilibria with poloidal, toroidal, and helical symmetry, achieving Mercier, ideal ballooning, and as a consequence, improved kinetic ballooning stability. We discover stellarators with second stability, a regime of large pressure gradient where an equilibrium becomes ideal ballooning stable, and demonstrate and explore both using theory and gyrokinetic simulations the connection between ideal and kinetic ballooning stability.

optimization↗
DOE OSTI2018

Correlation of the tokamak H-mode density limit with ballooning stability at the separatrix

We show for JET and ASDEX Upgrade, based on Thomson-scattering measurements, a clear correlation of the density limit of the tokamak H-Mode highcon nement regime with the approach to the ideal ballooning instability threshold at the periphery of the plasma. It is shown that the MHD ballooning parameter at the separatrix position αsep increases about linearly with the separatrix density normalized to Greenwald density, n e,sep =n GW for a wide range of discharge parameters in both devices. The observed operational space is found to reach at maximum n e,sep =nGW ≈ 0.4-0.5 at values for α sep ≈ 2-2.5, in the range of theoretical predictions for ballooning instability. This work supports the hypothesis that the H-Mode density limit may be set by ballooning stability at the separatrix.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2015

TU-AB-201-07: Image Guided Endorectal HDR Brachytherapy Using a Compliant Balloon Applicator

Purpose: High dose rate endorectal brachytherapy is an option to deliver a focal, high-dose radiotherapy to rectal tumors for patients undergoing non-operative management. We investigate a new multichannel, MR compatible applicator with a novel balloon-based design to provide improved treatment geometry. We report on the initial clinical experience using this applicator. Methods: Patients were enrolled on an IRB-approved, dose-escalation protocol evaluating the use of the anorectal (AR-1) applicator (Ancer Medical, Hialeah, FL), a multichannel applicator with two concentric balloons. The inner balloon supports 8 source lumens; the compliant outer balloon expands to separate the normal rectal wall and the source lumens, yet deforms around a firm, exophytic rectal mass, leading to dose escalation to tumor while sparing normal rectum. Under general anesthesia, gold fiducial markers were inserted above and below the tumor, and the AR applicator was placed in the rectum. MRI-based treatment plans were prepared to deliver 15 Gy in 3 weekly fractions to the target volume while sparing healthy rectal tissue, bladder, bowel and anal muscles. Prior to each treatment, CBCT/Fluoroscopy were used to place the applicator in the treatment position and confirm the treatment geometry using rigid registration of the CBCT and planning MRI. After registration of the applicator images, positioning was evaluated based on the match of the gold markers. Results: Highly conformal treatment plans were achieved. MR compatibility of the applicator enabled good tumor visualization. In spite of the non-rigid nature of the applicators and the fact that a new applicator was used at each treatment session, treatment geometry was reproducible to within 2.5 mm. Conclusions: This is the first report on using the AR applicator in patients. Highly conformal plans, confidence in MRI target delineation, in combination with reproducible treatment geometry provide encouraging feedback for continuation with dose escalation in these patients.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

SU-F-T-45: Dosimetric Effects of Saline Filled Balloons During IORT Using Xoft Electronic Brachytherapy

Purpose: The portability of Xoft Axxent Electronic Brachytherapy (EBx) System has made it a viable option for intraoperative radiation therapy (IORT) treatment of early-stage breast cancer. The low energy (50kVp) of the X-ray source makes the shielding easy, but also means its dose distribution is sensitive to the medium’s composition. Current treatment planning systems (TPS) typically assume homogenous water for brachytherapy dose calculations, including the pre-calculated atlas plans for the Xoft IORT cases. However, Xoft recommends using saline to fill the balloon applicator. This study investigates the dosimetric difference due to the increased effective atomic number (Zeff) from water (7.42) to saline (7.56). Methods: The diameter of the balloon applicators ranges from 3–6cm, with 4cm being most frequently used. For the 4-cm and 6-cm diameter applicators, MCNP Monte Carlo program was used to calculate the dose at the surface (Ds) of the middle section of the balloon and 1 cm away (D1cm) for water- and saline-filled balloons: one plan with a single dwell at the center and another with multiple dwells as in the atlas plans. The single dwell plan is a simple estimation of the dosimetry, while the atlas plan is representative of the actual dose distribution. Results: The single-dwell plan showed a 5.1% and 6.1% decrease in Ds for the 4- and 6-cm applicators, respectively, due to the saline. The atlas plan showed similar Results: 4.8% and 6.4% decrease, respectively. The decrease in D1cm is 4.3%–5.2% and 3.3%–5.3s% in the single-dwell and atlas plans, respectively, for the 4- and 6-cm applicator. Conclusion: The dosimetric effect introduced by saline is on the order of 5%. This effect should be taken into account during both treatment planning and patient outcome studies.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2022

Infrasound direction of arrival determination using a balloon-borne aeroseismometer

Free-floating balloons are an emerging platform for infrasound recording, but they cannot host arrays sufficiently wide for multi-sensor acoustic direction finding techniques. Because infrasound waves are longitudinal, the balloon motion in response to acoustic loading can be used to determine the signal azimuth. This technique, called “aeroseismometry,” permits sparse balloon-borne networks to geolocate acoustic sources. This is demonstrated by using an aeroseismometer on a stratospheric balloon to measure the direction of arrival of acoustic waves from successive ground chemical explosions. A geolocation algorithm adapted from hydroacoustics is then used to calculate the location of the explosions.

47 OTHER INSTRUMENTATION↗
DOE OSTI2020

Heliotrope: A Solar Powered Hot Air Balloon Flight System

What it is: A roughly spherical balloon constructed from light duty painter's plastic (0.31 mil high density polyethylene) and darkened with air float charcoal powder. Balloons typically range from 12-40 ft across depending on mission needs. How it works: Sunlight shines on the balloon, heating the air inside. The density difference due to the hot air in the balloon is sufficient to lift it up to 80,000 ft in the air

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

The Analysis and Support for LANL Technology Testbed: High Altitude Balloon Gondola and Orion Eagle Gamma Ray Detection Instrument

The Analysis and Support for LANL Technology Testbed: High Altitude Balloon Gondola and Orion Eagle Gamma-Ray Detection Instrument is a project where Los Alamos National Laboratory (LANL), in conjunction with the University of Michigan, are looking into gamma-ray detection in a space-like environment. The purpose of the detection is to work on instruments that can assist with planetary exploration and nuclear deterrents using a High-Altitude Balloon (HAB). For this paper, the main focus is on the mechanical aspects related to the structural analysis of the gondola. It is vital to understand the structural analysis because it helps determine if the gondola can survive the changes in the environment and the different forces or shocks that it will experience when the parachute is deployed and at landing. Additionally, NASA's Balloon Program Office (BPO) has specific requirements to meet to achieve flight certifications. Part of those certifications requires the gondola to simulate different scenarios at specific conditions with various forces applied and orientations. Therefore, it is necessary to adjust the calculations of each method and the force applied to get the right results. Once that is done, the information is inputted into the structural analysis modeling system. The system will aid the mechanical team in assessing the conditions of the gondola at each scenario and determine its margin of safety. After the gondola and instrument are certified, the payload will be able to fly. The HAB and payload are launched from NASA's Columbia Scientific Balloon Facility (CSBF) at Fort Sumner, NM. The official flight was on September 26th, 2021.

42 ENGINEERING↗
DOE OSTI2024

A banner year for solar balloon technology

Solar-powered stratospheric balloons achieved major advancements in test flights, developmental milestones, and operational achievements this year. A solar-powered stratospheric balloon system known as the heliotrope, has emerged as a low-cost platform capable of carrying several pounds of scientific payload to altitudes ranging from 50,000 to 75,000 feet (Bowman et al., 2020; Image 1) for multi-hour level flights. This innovative system has facilitated groundbreaking scientific discoveries in areas such as infrasound and atmospheric composition. Unlike sealed weather balloons that burst, these balloons remain buoyant by retaining hot air within their open envelopes. Because they are solar-powered, they remain aloft as long as the sun remains unobscured.

14 SOLAR ENERGY↗
DOE OSTI2025

Neutrally-buoyant balloons experiment – EMRTC 2025

This memo announces the successful execution of the neutrally-buoyant balloon experiment (EMRTC 2025), conducted at New Mexico Institute of Mining and Technology’s Energetic Materials Research and Testing Center (EMRTC) in Socorro, NM between April 3 and May 9, 2025. The experiment aimed to build on EMRTC 2022 balloon experiment through testing the effects of lateral and vertical displacement of release locations in a different terrain than EMRTC 2022. EMRTC 2025 employed dual GPS trackers on each balloon to provide both detailed near-source motion tracking in addition to the low-frequency long-distance trackers used in EMRTC 2022. A total of 156 neutrally-buoyant balloons were released over the week of May 5-9, which was approximately 2.5 times the number released in the EMRTC 2022 campaign. The dual tracking system will allow characterizing complex three-dimensional wind structures close to terrain features and diurnal wind patterns to validate wind and plume dispersion models for treaty verification.

99 GENERAL AND MISCELLANEOUS↗
NASA NTRS1971

Proposed techniques for launching instrumented balloons into tornadoes

A method is proposed to introduce instrumented balloons into tornadoes by means of the radial pressure gradient, which supplies a buoyancy force driving to the center. Presented are analytical expressions, verified by computer calculations, which show the possibility of introducing instrumented balloons into tornadoes at or below the cloud base. The times required to reach the center are small enough that a large fraction of tornadoes are suitable for the technique. An experimental procedure is outlined in which a research airplane puts an instrumented, self-inflating balloon on the track ahead of the tornado. The uninflated balloon waits until the tornado closes to, typically, 750 meters; then it quickly inflates and spirals up and into the core, taking roughly 3 minutes. Since the drive to the center is automatically produced by the radial pressure gradient, a proper launch radius is the only guidance requirement.

Grant, F. C.↗
NASA NTRS1971

Nimbus 4/IRLS Balloon Interrogation Package (BIP)

The balloon interrogation package (BIP), an integral part of the overall interrogation, recording, and location subsystems (IRLS) for the Nimbus 4 program, is described. The BIP is a self-contained, integrated transponder designed to be carried aloft by a constant altitude, superpressure balloon to an altitude of 67,000 or 78,000 feet. After launch the BIP senses high-altitude balloon overpressure and temperature, and upon receipt of an interrogated command from the IRLS aboard the Nimbus 4 satellite, the BIP enodes the data on a real-time basis into a pulse-code modulation (PCM) format and transmits this data to the satellite. A summary of the program activity to produce 30 BIP systems and to support balloon launches from Ascension Island is presented.

Source record↗
NASA NTRS1970

Absorption spectrometer balloon flight and iodine investigations

A high altitude balloon flight experiment to determine the technical feasibility of employing absorption spectroscopy to measure SO2 and NO2 gases in the earth's atmosphere from above the atmospheric ozone layer is discussed. In addition to the balloon experiment the contract includes a ground-based survey of natural I emissions from geological sources and studies of the feasibility of mapping I2 from spacecraft. This report is divided into three major sections as follows: (1) the planning engineering and execution of the balloon experiment, (2) data reduction and analysis of the balloon data, and (3) the results of the I2 phase of the contract.

Source record↗
NASA NTRS1972

Behavior of spherical balloons in wind shear layers.

Analysis of the response of rising spherical balloons to a constant wind shear condition. Wind shear tends to produce a terminal rise rate that is less than the terminal rise rate in the absence of wind shear by no more than 1% of the wind shear and a horizontal balloon velocity defect relative to the local wind with magnitude less than or about equal to 0.2 of the wind shear for most meteorological balloons. An analysis of the behavior of a balloon in a wind field in which the wind shear varies along the vertical is also presented.

Fichtl, G. H.↗