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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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

Ballooning theory of the second kind-two dimensional tokamak modes

The 2-D ballooning transform, devised to study local high toroidal number (n) fluctuations in axisymmetric toroidal system (like tokamaks), yields a well-defined partial differential equation for the linear eigenmodes. In this paper, such a ballooning equation of the second kind is set up for ion temperature gradient driven modes pertinent to a 2-D non-dissipative fluid plasma; the resulting partial differential equation is numerically solved, to calculate the global eigenvalues, and the 2-D mode structure is presented graphically along with analytical companions. The radial localization of the mode results from translational symmetry breaking for growing modes and is a vivid manifestation of spontaneous symmetry breaking in tokamak physics. The eigenmode, poloidally ballooned at {theta}={+-}{pi}/2, is radially shifted from associated rational surface. The global eigenvalue is found to be very close to the value obtained in 1-D parameterized ({lambda}={+-}{pi}/2) case. The 2-D eigenmode theory is applied to estimate the toroidal seed Reynolds stress [Y. Z. Zhang, Nucl. Fusion Plasma Phys. 30, 193 (2010)]. The solution obtained from the relatively simplified ballooning theory is compared to the solution of the basic equation in original coordinate system (evaluated via FFTs); the agreement is rather good.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

Background Measurements and Simulations of the ComPair Balloon Flight

ComPair, a prototype of the All-sky Medium Energy Gamma-ray Observatory (AMEGO), completed a short-duration high-altitude balloon campaign on 27 August 2023 from Fort Sumner, New Mexico, USA. The goal of the balloon flight was to demonstrate ComPair as both a Compton and Pair telescope in flight, reject the charged particle background, and measure the background γ-ray spectrum. This analysis compares measurements from the balloon flight with Monte Carlo simulations to benchmark the instrument. The comparison finds good agreement between the measurements and simulations and supports the conclusion that ComPair accomplished its goals for the balloon campaign. Additionally, two charged particle background rejection schemes are discussed: a soft ACD veto that records a higher charged particle event rate but with less risk of event loss, and a hard ACD veto that limits the charged particle event rate on board. There was little difference in the measured spectra from the soft and hard ACD veto schemes, indicating that the hard ACD veto could be used for future flights. The successes of ComPair’s engineering flight will inform the development of the next generation of ComPair with upgraded detector technology and larger active area.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

Isolating the Source Region of Infrasound Travel Time Variability Using Acoustic Sensors on High-Altitude Balloons

High-altitude balloons carrying infrasound sensor payloads can be leveraged toward monitoring efforts to provide some advantages over other sensing modalities. On 10 July 2020, three sets of controlled surface explosions generated infrasound waves detected by a high-altitude floating sensor. One of the signal arrivals, detected when the balloon was in the acoustic shadow zone, could not be predicted via propagation modeling using a model atmosphere. Considering that the balloon’s horizontal motion showed direct evidence of gravity waves, we examined their role in infrasound propagation. Implementation of gravity wave perturbations to the wind field explained the signal detection and aided in correctly predicting infrasound travel times. Our results show that the impact of gravity waves is negligible below 20 km altitude; however, their effect is important above that height. The results presented here demonstrate the utility of balloon-borne acoustic sensing toward constraining the source region of variability, as well as the relevance of complexities surrounding infrasound wave propagation at short ranges for elevated sensing platforms.

47 OTHER INSTRUMENTATION↗
DOE OSTI2018

The EBEX Balloon-borne Experiment—Detectors and Readout

EBEX was a long-duration balloon-borne experiment to measure the polarization of the cosmic microwave background. The experiment had three frequency bands centered at 150, 250, and 410 GHz and was the first to use a kilopixel array of transition edge sensor bolometers aboard a balloon platform. We determine the design and characterization of the array and the readout system. From the lowest to highest frequency, the median measured detectors' average thermal conductances were 39, 53, and 63 pW/K, the medians of transition temperatures were 0.45, 0.48, and 0.47 K, and the medians of normal resistances were 1.9, 1.5, and 1.4 Ω; moreover, we give the measured distributions. With the exception of the thermal conductance at 150 GHz, all measured values are within 30% of their design. We measure median low-loop-gain time constants τ 0 = 88, 46, and 57 ms. Two measurements of bolometer absorption efficiency gave results consistent within 10% and showing high (~0.9) efficiency at 150 GHz and medium (~0.35 and ~0.25) efficiency at the two higher bands. We calculate a median total optical power absorbed of 3.6, 5.3, and 5.0 pW. EBEX pioneered the use of the digital version of the frequency domain multiplexing system. We multiplexed the bias and readout of 16 bolometers onto two wires. The median per-detector noise-equivalent temperatures are 400, 920, and 14,500 $\mu {{\rm{K}}}_{{\rm{cmb}}}\sqrt{{\rm{s}}}$. We compare these values to our preflight predictions and to a previous balloon payload. We report on the sources of excess noise and the path for a future payload to make full use of the balloon environment.

instrumentation: polarimeters↗
NASA NTRS2000

Innovative Balloon Buoyancy Techniques for Atmospheric Exploration

Until quite recently, the only practical means to control balloon buoyancy, and thus altitude, required consuming large amounts of fuel or the limited venting of helium balloons and/or dropping of ballast. With recent discoveries at JPL, novel long-life, balloon buoyancy techniques have been discovered that for the first time allow balloons to float in the primarily hydrogen atmospheres of Jupiter, Saturn, Uranus, and Neptune (using ambient fill-gas), and by using renewable energy sources, allow multiple controlled landings on Venus (using atmospheric temperature differences), Mars (solar heat), Titan (RTG heat), and Earth (planet radiant heat).

Balloon Planetary Aerobot Buoyancy Mars Titan Venu↗
NASA NTRSDate not supplied

Exploring the Potential of Hydrogen as a Lift Gas for Nasa’s Scientific Balloon Program

The United States National Aeronautics and Space Administration (NASA) Balloon Program has a rich history of conducting scientific research in the stratosphere, offering a unique platform for experiments in the near-space environment. One critical component of these high-altitude balloons is the choice of lift gas, which is pivotal to achieving the desired altitude and, thus, mission objectives. Traditionally, helium has been the preferred lift gas due to its inert properties and safety considerations. However, the increasing demand and limited global helium reserves have prompted NASA to explore alternative lift gases, with hydrogen emerging as the most logical choice. Hydrogen boasts several advantages, including its abundant availability, cost-effectiveness, and enhanced lift capability compared to helium. Moreover, it can support a wide range of scientific payloads, enabling extended mission durations and increased payload capacities, ultimately strengthening the program’s scientific potential. However, adopting hydrogen as a lift gas is not without challenges. Safety concerns, especially during the launch and recovery phases, are paramount. NASA and the other major players in the scientific ballooning community have been developing stringent safety protocols and engineering solutions to mitigate these risks. This development includes specialized support systems, leak detection mechanisms, and enhanced launch and recovery procedures. Additionally, environmental considerations must be carefully evaluated. Hydrogen release has the potential to increase concentrations of various greenhouse gases, and its usage must be balanced against the benefits it offers to scientific research and exploration. This paper delves into the ongoing research and development efforts to ensure balloon-based research’s long-term sustainability and its ability to continue pushing the boundaries of scientific discovery. This research demonstrates NASA’s commitment to innovation, safety, and environmental responsibility while maintaining its mission to advance our understanding of the Earth and the cosmos.

balloon↗
DOE OSTI2011

Cerebrospinal Fluid Enhancement on Fluid Attenuated Inversion Recovery Images After Carotid Artery Stenting with Neuroprotective Balloon Occlusions: Hemodynamic Instability and Blood-Brain Barrier Disruption

Purpose: A rare complication of carotid artery stenting (CAS), prolonged reversible neurological symptoms with delayed cerebrospinal fluid (CSF) space enhancement on fluid attenuated inversion recovery (FLAIR) images, is associated with blood-brain barrier (BBB) disruption. We prospectively identified patients who showed CSF space enhancement on FLAIR images. Methods: Nineteen patients-5 acute-phase and 14 scheduled-underwent 21 CAS procedures. Balloon catheters were navigated across stenoses, angioplasty was performed using a neuroprotective balloon, and stents were placed with after dilation under distal balloon protection. CSF space hyperintensity or obscuration on FLAIR after versus before CAS indicated CSF space enhancement. Correlations with clinical factors were examined. Results: CSF space was enhanced on FLAIR in 12 (57.1%) cases. Postprocedural CSF space enhancement was significantly related to age, stenosis rate, acute-stage procedure, and total occlusion time. All acute-stage CAS patients showed delayed enhancement. Only age was associated with delayed CSF space enhancement in scheduled CAS patients. Conclusions: Ischemic intolerance for severe carotid artery stenosis and temporary neuroprotective balloon occlusion, causing reperfusion injury, seem to be the main factors that underlie BBB disruption with delayed CSF space enhancement shortly after CAS, rather than sudden poststenting hemodynamic change. Our results suggest that factors related to hemodynamic instability or ischemic intolerance seem to be associated with post-CAS BBB vulnerability. Patients at risk for hemodynamic instability or with ischemic intolerance, which decrease BBB integrity, require careful management to prevent intracranial hemorrhagic and other post-CAS complications.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Paget-Schroetter Syndrome Treated with Cutting-Balloon Angioplasty

Here, a case of Paget-Schroetter Syndrome in a 25-year-old guitar player is reported. After thrombolysis, conventional angioplasty failed to dilate the underlying subclavian stenosis both before and after first-rib excision with scalenus anterior and medius division. For the third attempt at angioplasty, a cutting balloon was used, which immediately produced a good result. Venography at 4-year follow-up showed no restenosis and no functional deficit. This case report demonstrates that cutting-balloon angioplasty may be considered when conventional balloon fails and may have greater durability than conventional balloon angioplasty in the treatment of Paget-Schroetter syndrome.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2016

Balloon Blocking Technique (BBT) for Superselective Catheterization of Inaccessible Arteries with Conventional and Modified Techniques

PurposeThe purpose of the study was to retrospectively evaluate the efficacy and safety of the balloon blocking technique (BBT).Materials and MethodsThe BBT was performed in six patients (all males, mean 73.5 years) in whom superselective catheterization for transcatheter arterial embolization by the conventional microcatheter techniques had failed due to anatomical difficulty, including targeted arteries originating steeply or hooked from parent arteries. All BBT procedures were performed using Seldinger’s transfemoral method. Occlusive balloons were deployed and inflated at the distal side of the target artery branching site in the parent artery via transfemoral access. A microcatheter was delivered from a 5-F catheter via another femoral access and was advanced over the microguidewire into the target artery, under balloon blockage of advancement of the microguidewire into non-target branches. After the balloon catheter was deflated and withdrawn, optimal interventions were performed through the microcatheter.ResultsAfter success of accessing the targeted artery by BBT, optimal interventions were accomplished in all patients with no complications other than vasovagal hypotension, which responded to nominal therapy.ConclusionThe BBT may be useful in superselective catheterization of inaccessible arteries due to anatomical difficulties.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

Balloon-Occluded Carbon Dioxide Gas Angiography for Internal Iliac Arteriography and Intervention

IntroductionThe usefulness of carbon dioxide (CO{sub 2}) gas digital subtraction angiography (DSA) has been reported for patients with renal insufficiency and allergy to iodinated contrast agents. However, CO{sub 2} gas cannot replace the iodinated contrast agent in all cases owing to some disadvantages. We describe balloon-occluded CO{sub 2} DSA (B-CO{sub 2} DSA) as an improved CO{sub 2} DSA procedure for interventions in the internal iliac artery (IIA) region and compare the quality of images obtained using conventional CO{sub 2} DSA and B-CO{sub 2} DSA.Materials and MethodsB-CO{sub 2} DSA-guided embolization was performed for one case of genital bleeding with an acute anaphylactic reaction to the iodinated contrast agent and for three cases of type II endoleaks after endovascular abdominal aortic aneurysm repair with renal dysfunction. A 9-mm occlusion balloon catheter was placed just after the orifice of the IIA. Then, 10–15 ml of CO{sub 2} gas was injected manually via the catheter with and without balloon occlusion. The quality of sequential digital subtraction angiograms was analyzed based on a scoring criterion.ResultsIn all four cases, image quality was improved with B-CO{sub 2} DSA; the poor quality of images without balloon occlusion was because of reflux of the CO{sub 2} gas.ConclusionsB-CO{sub 2} DSA improves the image quality of CO{sub 2} DSA in the IIA region and is useful for vascular intervention. Level of Evidence: Level IV.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Balloon-Occluded Transcatheter Arterial Chemoembolization (b-TACE) for Hepatocellular Carcinoma Performed with Polyethylene-Glycol Epirubicin-Loaded Drug-Eluting Embolics: Safety and Preliminary Results

Purpose: To report technical success, safety profile and oncological results of balloon-occluded transcatheter arterial chemoembolization using a balloon micro-catheter and epirubicin-loaded polyethylene-glycol (PEG) microsphere (100 ± 25 µm and 200 ± 50 µm) in patients with hepatocellular carcinoma (HCC). Materials and Methods: This is a single-centre, single-arm, retrospective study with 6-month follow-up. Twenty-two patients (Child–Pugh A 68% [15/22], B in 32% [7/22]; age 67.05 ± 14 years) with 29 HCC were treated in 24 procedures. Technical success is defined: ability to place the balloon micro-catheter within the required vascular segment, balloon-occluded arterial stump pressure drops and assessment of microsphere deposition. Laboratory assessment pre/post-procedural and complications were analysed, respectively, according to Common Terminology Criteria for Adverse Events (CTCAEv5) and CIRSE system. Postembolization syndrome (PES) was defined as fever and/or nausea and/or pain onset. Oncological results were evaluated using m-RECIST criteria with CT/MRI imaging at 1 and 3–6 months. In partial responder patients, pre/post-procedural tumour volume was compared. Results: Pre-planned feeder was reached in all cases. Pressure drop average was 51.1 ± 21.6 mmHg. Exclusive target embolization was achieved in 14/24 procedures (58.3%). Laboratory test modifications were all grade 1. 4/24 adverse events occurred (17%): pseudo-aneurysm of the feeder (grade 3), liver abscess (grade 2) and 2 asymptomatic segmentary biliary tree dilatations (grade 2). PES occurred in 8/24 (33%). The complete response at 1 and 3–6 months was 44.8% (13/29) and 52.9% (9/17), respectively. The partial response at 1 and 3–6 months was 55% (16/29) and 4/17 (23.5%), respectively. Among partial responder patients, the average percentage of tumour volume reduction was 64.9 ± 27.3%. Conclusion: Epirubicin-loaded PEG microsphere b-TACE is technically feasible, safe and effective procedure for HCC treatment.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Drug-Eluting Balloon Angioplasty for Juxta-Anastomotic Stenoses in Distal Radiocephalic Hemodialysis Fistulas: Long-Term Patency Results

Purpose: To evaluate long-term primary and secondary patency results of drug-eluting balloon angioplasty for the treatment of juxta-anastomotic stenoses in distal radiocephalic arteriovenous fistulas. Materials and Methods: Thirty-eight patients with juxta-anastomotic stenotic distal radiocephalic arteriovenous fistulas who underwent endovascular treatment with drug-eluting balloons between January 2014 and August 2016 in our interventional radiology department were included in this retrospective study. Color Doppler examination for follow-up was performed 15 days, 6 months, 12 months, 18 months, 24 months, 36 months, and 48 months after the procedure. Kaplan–Meier analysis was used to estimate primary and secondary patency rates. Results: Totally, 42 angioplasty with drug-eluting balloons was performed in 38 patients (20 men and 18 women; mean age 66.42 ± 12.01). Technical and clinical success rate was 100% (42/42). The mean follow-up period was 27.71 months ± 12.98 (range, 1–54 months). The estimated primary patency rates at 6 months were 94.7% (95% CI, 80.9%–99.0%), at 12 months were 81.2% (95% CI, 64.6%–91.4%), at 24 months were 60.7% (95% CI, 43.6%–75.7%), and at 48 months were 53.1% (95% CI, 36.5%–69.1%). The estimated secondary patency rates at 6 months were 97.3% (95% CI, 84.5%–99.8%), at 12 months were 86.5% (95% CI, 70.7%–94.8%), at 24 months were 69.0% (95% CI, 51.8%–82.4%), and at 48 months were 61.7% (95% CI, 44.6%–76.5%). Conclusion: Drug-eluting balloon angioplasty is a useful, effective technique in dysfunctional radiocephalic fistulas due to juxta-anastomotic stenoses. We demonstrated remarkably high primary patency rates at 6, 12, 24, and 48 months.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
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↗