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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 1,297 records · Page 72
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Suitability of Exoseal Vascular Closure Device for Antegrade Femoral Artery Puncture Site Closure

Purpose. To assess the efficacy and safety of the Exoseal vascular closure device for antegrade puncture of the femoral artery. Methods. In a prospective study from February 2011 to January 2012, a total of 93 consecutive patients received a total of 100 interventional procedures via an antegrade puncture of the femoral artery. An Exoseal vascular closure device (6F) was used for closure in all cases. Puncture technique, duration of manual compression, and use of compression bandages were documented. All patients were monitored by vascular ultrasound and color-coded duplex sonography of their respective femoral artery puncture site within 12 to 36 h after angiography to check for vascular complications. Results. In 100 antegrade interventional procedures, the Exoseal vascular closure device was applied successfully for closure of the femoral artery puncture site in 96 cases (96 of 100, 96.0 %). The vascular closure device could not be deployed in one case as a result of kinking of the vascular sheath introducer and in three cases because the bioabsorbable plug was not properly delivered to the extravascular space adjacent to the arterial puncture site, but instead fully removed with the delivery system (4.0 %). Twelve to 36 h after the procedure, vascular ultrasound revealed no complications at the femoral artery puncture site in 93 cases (93.0 %). Minor vascular complications were found in seven cases (7.0 %), with four cases (4.0 %) of pseudoaneurysm and three cases (3.0 %) of significant late bleeding, none of which required surgery. Conclusion. The Exoseal vascular closure device was safely used for antegrade puncture of the femoral artery, with a high rate of procedural success (96.0 %), a low rate of minor vascular complications (7.0 %), and no major adverse events.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

Gelatin Microspheres: Correlation between Embolic Effect/Degradability and Cross-linkage/Particle Size

PurposeTo evaluate the embolic effect and degradability of gelatin microspheres (GMS) using various degrees of cross-linkage and particle sizes in rabbit renal artery embolization.MethodsFour types of GMS were used, as follows: 2 types of cross-linkage and 2 types of particle size. Twenty-four rabbits (6 in each group) were used for the renal artery embolization. Renal angiography was performed before and after embolization of right renal artery. Follow-up renal angiography was performed 2 days (n = 2), 5 days (n = 2), and 15 days (n = 2) after embolization in each group, and then kidneys were removed for histopathological evaluation. Vascular areas of the angiography were measured by Image J software, and the reperfusion rate was calculated. In renal specimens, residual GMS were checked and the degree of degradation was classified according to a 4-point scale.ResultsThe mean amounts of large- and small-particle-size GMS injected were 15.0 and 34.3 mg, respectively. Tissue necrosis was confirmed in each group; however, no difference was observed among groups. Renal reperfusion was observed more with small GMS than with large GMS. Renal reperfusion was also observed more with low cross-linked GMS than with high cross-linked GMS. In histopathological specimens, large GMS were confirmed in lobar artery, and small GMS were confirmed in lobular artery. Low cross-linked GMS completely degraded 15 days after embolization. In contrast, high cross-linked GMS were persistent 15 days after embolization.ConclusionDegree of cross-linkage and particle size affected degradability and reperfusion.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2016

First Delayed Resection Findings After Irreversible Electroporation (IRE) of Human Localised Renal Cell Carcinoma (RCC) in the IRENE Pilot Phase 2a Trial

IntroductionIt is postulated that focal IRE affords complete ablation of soft-tissue tumours while protecting the healthy peritumoral tissue. Therefore, IRE may be an interesting option for minimally invasive, kidney-tissue-sparing, non-thermal ablation of renal tumours.AimWith this current pilot study (“IRENE trial”), we present the first detailed histopathological data of IRE of human RCC followed by delayed tumour resection. The aim of this interim analysis of the first three patients was to investigate the ablation efficiency of percutaneous image-guided focal IRE in RCC, to assess whether a complete ablation of T1a RCC and tissue preservation with the NanoKnife system is possible and to decide whether the ablation parameters need to be altered.MethodsFollowing resection 4 weeks after percutaneous IRE, the success of ablation and detailed histopathological description were used to check the ablation parameters.ResultsThe IRE led to a high degree of damage to the renal tumours (1 central, 2 peripheral; size range 15–17 mm). The postulated homogeneous, isomorphic damage was only partly confirmed. We found a zonal structuring of the ablation zone, negative margins and, enclosed within the ablation zone, very small tumour residues of unclear malignancy.ConclusionAccording to these initial, preliminary study results of the first three renal cases, a new zonal distribution of IRE damage was described and the curative intended, renal saving focal ablation of localised RCC below <3 cm by percutaneous IRE by the NanoKnife system appears to be possible, but needs further, systematic evaluation for this treatment method and treatment protocol.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2016

Endovascular Management of Intractable Postpartum Hemorrhage Caused by Vaginal Laceration

PurposeWe evaluated the management of transcatheter arterial embolization for postpartum hemorrhage caused by vaginal laceration.Materials and MethodsWe reviewed seven cases of patients (mean age 30.9 years; range 27–35) with intractable hemorrhages and pelvic hematomas caused by vaginal lacerations, who underwent superselective transcatheter arterial embolization from January 2008 to July 2014. Postpartum hemorrhage was evaluated by angiographic vascular mapping to determine the vaginal artery’s architecture, technical and clinical success rates, and complications.ResultsThe vaginal artery was confirmed as the source of bleeding in all cases. The artery was found to originate from the uterine artery in three cases, the uterine and obturator arteries in two, or the internal pudendal artery in two. After vaginal artery embolization, persistent contrast extravasation from the inferior mesenteric artery as an anastomotic branch was noted in one patient. Nontarget vessels (the inferior vesical artery and nonbleeding vaginal arterial branches) were embolized in one patient. Effective control of hemostasis and no post-procedural complications were confirmed for all cases.ConclusionPostpartum hemorrhages caused by vaginal lacerations involve the vaginal artery arising from the anterior trunk of the internal iliac artery with various branching patterns. Superselective vaginal artery embolization is clinically acceptable for the successful treatment of vaginal laceration hemorrhages, with no complications. After vaginal artery embolization, it is suggested to check for the presence of other possible bleeding vessels by pelvic aortography with a catheter tip at the L3 vertebral level, and to perform a follow-up assessment.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Percutaneous Lung Tumor Biopsy Under CBCT Guidance with PET-CT Fusion Imaging: Preliminary Experience

Purpose: The aim of this study is to evaluate the feasibility of percutaneous lung tumor biopsy under cone beam-computed tomography (CBCT) with PET-CT imaging fusion. Materials and Methods: Eleven patients (four women and seven men) underwent C-arm CBCT lung biopsy with PET-CT fusion imaging. A preprocedural PET-CT scan was manually fused with procedural CBCT based on anatomical landmarks; using real-time fluoroscopy, the coregistered PET-CT and CBCT images were overlaid to guide the needle trajectory. Technical success, accuracy, sensibility and specificity were evaluated. Mean total procedure time and time required for image elaboration were recorded. Results: Technical success, diagnostic accuracy, sensitivity and specificity were 100%. The mean procedure time was 38 min. The average time of PET-CT/CBCT image fusion elaboration was 3.53 min for planning and 3.42 min for needle positioning check. Conclusion: CBCT-guided percutaneous lung biopsy with PET-CT fusion imaging is a feasible and effective procedure, with the potential to further improve diagnostic yield by targeting the most metabolically active portion of a lesion, whether it is morphologically altered or normal.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

CLAS N* Excitation Results from Pion and Kaon Electroproduction

The study of the structure of excited nucleon $N^*$ states employing the electroproduction of exclusive reactions is an important avenue for exploring the nature of the non-perturbative strong interaction. The electrocouplings of $N^*$ states in the mass range below $W$=1.8~GeV have been determined from analyses of CLAS $\pi N$, $\eta N$, and $\pi \pi N$ data at four-momentum transfers $Q^2$ up to 5~GeV$^2$. The work has made it clear that consistent results from independent analyses of several exclusive channels with different couplings and non-resonant backgrounds but the same $N^*$ electroexcitation amplitudes, is essential to have confidence in the extracted results. In terms of hadronic couplings, many high-lying $N^*$ states preferentially decay through the $\pi \pi N$ channel, while couplings to $\pi N$ final states become rather small. The resonance parameters determined from $\pi N$ and $\pi \pi N$ electroproduction can be checked in independent studies of the $KY$ ($Y = \Lambda, \Sigma^0$) channels. Therefore, data from the $KY$ channels already measured with CLAS will play an important role in $N^*$ structure studies. These comparisons await the development of suitable reaction models. Starting in 2018, a program to study the structure of $N^*$ states in various exclusive electroproduction channels using the new CLAS12 spectrometer will get underway. These studies will probe the structure of $N^*$ states in the mass range up to $W$=3~GeV and $Q^2$ up to 12~GeV$^2$, thus providing a means to access $N^*$ structure information spanning a broad regime encompassing both low- and high-energy degrees of freedom.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2024

A Study of the Transition to Turbulence in a Bed of 67 Spherical Pebbles

Packed beds are commonly found in many engineering systems and have been widely studied for decades. A relatively new packed bed system is the Pebble Bed Reactor, a type of generation-IV nuclear reactor. Unlike many of the packed beds encountered in chemical and process engineering applications, Pebble Bed Reactors are larger and operate at significantly higher Reynolds numbers. As a result of these differences, there is a very limited amount of information on the detailed flow physics that exist in these complex geometries. This work seeks to contribute to a growing database of flow data for Pebble Bed Reactor systems by performing Direct Numerical Simulations of the flow in an experimental bed of 67 pebbles for a range of conditions. Simulations are performed at a Prandtl number of 0.66 and Reynolds numbers from 300–600. These Reynolds numbers are chosen to gain additional knowledge on the spatial development of turbulence in these systems. Analysis of the Turbulent Kinetic Energy, turbulence anisotropy, and Turbulent Heat Flux is performed. Results demonstrate significant development of the TKE across the tested range of Reynolds numbers. Examination of both the TKE and THF reveal that development first occurs near the center of the bed and propagates radially as the flow moves further into the bed. Notable regions of negative production of turbulent kinetic energy are observed in regions where flow accelerates around pebble contact points. Furthermore, these regions are found to coincide with regions of 1-component turbulence.Kindly check and confirm, all authors email id is correctly identified.These are correct

Direct numberical simulation↗
DOE OSTI2019

Failure prediction using machine learning in a virtualised HPC system and application

Failure is an increasingly important issue in high performance computing and cloud systems. As large-scale systems continue to grow in scale and complexity, mitigating the impact of failure and providing accurate predictions with sufficient lead time remains a challenging research problem. Traditional existing fault-tolerance strategies such as regular check-pointing and replication are not adequate because of the emerging complexities of high performance computing systems. This necessitates the importance of having an effective as well as proactive failure management approach in place aimed at minimizing the effect of failure within the system. With the advent of machine learning techniques, the ability to learn from past information to predict future pattern of behaviours makes it possible to predict potential system failure more accurately. Thus, in this paper, we explore the predictive abilities of machine learning by applying a number of algorithms to improve the accuracy of failure prediction. We have developed a failure prediction model using time series and machine learning, and performed comparison based tests on the prediction accuracy. The primary algorithms we considered are the support vector machine (SVM), random forest (RF), k-nearest neighbors (KNN), classification and regression trees (CART) and linear discriminant analysis (LDA). Experimental results indicates that the average prediction accuracy of our model using SVM when predicting failure is 90% accurate and effective compared to other algorithms. This finding implies that our method can effectively predict all possible future system and application failures within the system.

Mohammed, Bashir↗
DOE OSTI2017

Hyperchaotic Analysis and Adaptive Projective Synchronization of Nonlinear Dynamical System

In this paper, a new nonlinear dynamical system has been studied which is obtained from the 3D chaotic system. The hyperchaotic analysis of the new system is checked in terms of dissipation, equilibrium points and their stability, Lyapunov exponent, time series, phase portraits, Poincaré section and bifurcation diagram. Furthermore, the adaptive projective synchronization technique is used to synchronize the novel hyperchaotic system. A brief theoretical analysis and simulation results are presented to prove the behavior of the novel hyperchaotic system.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2025

Equation of State for the Thermodynamic Properties of Trans-1,2-dichloroethene [R-1130(E)]

We present an empirical equation of state in terms of the Helmholtz energy for trans-1,2-dichloroethene [R-1130(E)]. The range of validity is from the triple-point temperature, 223.31 K to 525 K with pressures up to 30 MPa. It may be used to calculate all thermodynamic properties in the fluid phase, including liquid, gas, and supercritical regions. Comparisons are given with existing literature data and estimated uncertainties are provided. In addition, checks were made for correct extrapolation behavior so that the equation behaves in a physically realistic manner when used outside of its range of validity, enabling its use in mixture models. The estimated uncertainties (at a k = 2 or 95 % level of confidence) are based on comparisons with critically assessed data and are 0.25 % for vapor pressure for temperatures in the range 300 K < T < 454 K, rising to 1.5 % as the temperature decreases from 300 K to 265 K. For density in the liquid phase the estimated uncertainty is 0.14 % for temperatures 270 K < T < 410 K and for pressures up to 30 MPa. For the vapor phase the estimated uncertainty in density is 3 %. The uncertainty for liquid-phase heat capacity is 1 % at atmospheric pressure over the temperature range 268 K < T < 309 K, and the uncertainty for the speed of sound in the liquid phase is 0.25 % for temperatures 230 K < T < 420 K and for pressures up to 30 MPa. The uncertainties are larger outside of these specified ranges and in the critical region.

1,2-Dichloroethene↗
DOE OSTI2018

X-Ray Digital Radiography to Study Gold–Silver Nose Decorations from the Moche Tomb of the Lady of Cao

In the present study nose decorations from the tomb of the ‘Lady of Cao’, a mummified Moche woman dated around third–fourth century AD, were analyzed by a portable X-ray digital radiography (XDR) system. The Moche civilization flourished along the north coast of present-day Peru, between the Andes and the Pacific Ocean, approximately between 100 and 600 AD. The Moche were very sophisticated artisans and metal smiths, so that they are considered the finest producers of jewels and artifacts of the region. Their metalworking ability was impressively demonstrated by the excavations of the tomb of the ‘Lady of Cao’, discovered by Regulo Franco in 2005. More than 100 beautiful jewels were found in this tomb, among them about 40 nose decorations composed of a combination of gold and silver sheets. Radiographs of several of them were carried out, with the aim to evaluate the gold–silver joining process, to check the homogeneity of the alloy and to quantify the thickness of the sheets. The XDR system consisted of a mini X-ray tube and of a digital X-ray flat panel. The radiographic images of the nose decorations revealed details of the manufacturing process and of the Au–Ag junction.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Experimental Validation of the Horikx Theory to be Used in the Rubber Devulcanization Analysis

The waste rubber and end-of-life tires management has become a serious environmental problem. It is well known that the best way to carry out the disposal of these wastes is through recycling by devulcanization. Therefore, in the last decades, many methods have been developed to perform this treatment. Nevertheless, the degree and quality of the achieved devulcanization is still difficult to evaluate. The Horikx theory is an approach often used for this purpose. Hence, in this work, the validity of this theory was experimentally checked. The theoretical curve that represents crosslink scission was experimentally built for sulfur-cured natural rubber, sulfur-cured natural rubber reinforced with carbon black, sulfur-cured ethylene propylene diene monomer rubber and peroxide-cured ethylene propylene diene monomer rubber. Several samples with vulcanization (or devulcanization) degree ranging from 0 to 100% were processed, and the corresponding soluble fractions and crosslink densities were measured by the swelling test. The experimental results were in good agreement with the theoretical predictions, independently of the studied material, fact that confirms the validity of the Horikx approach. This finding will contribute to improve the waste rubber devulcanization, and therefore to progress in the environmental protection.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2017

Nanostructural Characterization of the Fe{sub 3}O{sub 4}/ZnO Magnetic Nanocomposite as an Application in Medicine

In the present work, we synthesize Fe{sub 3}O{sub 4}/ZnO nanocomposite by sol-gel method using iron nitrate, ethylene glycol, zinc acetate dehydrate, and ammonium carbonate as precursors. Amorphous matrix and crystalline grains were formed in composite as well. The nanostructural properties of the nanocomposite were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and colloidal stability was checked out by Zeta potential. The biological effects of Fe{sub 3}O{sub 4}/ZnO nanocomposite were investigated by microculture tetrazolium test (MTT) against MCF-7 breast cancer cells as usage in medicine. Crystallite size, lattice strain, and dislocation density of the nanoparticles were estimated with Williamson-Hall method. The obtained results show that the highest death rate of Michigan Cancer Foundation-7 (MCF-7) cancer cells was for Fe{sub 3}O{sub 4}/ZnO nanocomposite with the molar ratio is 1:10 in the lower concentration (49 μ g/ml). Therefore, these nanocomposites due to their small size, colloidal stability, magnetic properties, and nontoxicity can be a good candidate as option in medicine application.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Effect of Cr{sup 3+} Ions Substitution on Structural and Magnetic Properties of Co Ferrite Nanoparticles

A series of polycrystalline nanoferrite having the chemical formula CoCr{sub x}Fe{sub 2−x}O{sub 4} (x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) were synthesized by sol-gel autocombustion method. X-ray diffraction (XRD) analysis was used to investigate the structural parameters and also to check the phase purity of all prepared samples. The analysis of XRD patterns revealed the formation of single-phase cubic spinel structure for all samples. The average particle size of the synthesized ferrites was identified by X-ray diffraction and scanning electron microscopy technique. The magnetic properties of Co-Cr nanoferrites were measured using a hysteresis loop tracer at room temperature and magnetic field of 5 KOe. Saturation magnetization (M{sub s}) and coercivity (H{sub c}) decrease with the increasing Cr{sup 3+} ions concentration in the Co-Cr ferrite, indicating that lesser magnetic Cr{sup 3+} ions substitute Fe{sup 3+} ions in the octahedral sublattice of the ferrite. Such materials are useful to reduce the energy loss in AC electrical appliances.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Critical Properties of Perovskite Manganese Oxides Pr{sub 1−x}Ba{sub x}MnO{sub 3}

The critical properties of polycrystalline Pr{sub 1−x}Ba{sub x}MnO{sub 3} (x = 0.13 and 0.23) samples prepared by using a standard ceramic fabrication method were investigated. Pr{sub 1−x}Ba{sub x}MnO{sub 3} exhibited a second-order magnetic transition. As per the modified Arrott plot method and double logarithmic M-μ{sub 0}H curve, the critical exponents (CE) were calculated as β = 0.459 ± 0.03, γ = 1.346 ± 0.02, δ = 4.32 ± 0.04, and T{sub C} ≈ 130 K, for x = 0.13, and β = 0.424 ± 0.03, γ = 1.362 ± 0.02, δ = 4.19. ± 0.03, and T{sub C} ≈ 163 K, for x = 0.23. To confirm the reliability of such CE values, the M (H) data of Pr{sub 1−x}Ba{sub x}MnO{sub 3} were checked by the scaling equation M(H, t) = |t|{sup β}f{sub ±}(H/|t|{sup β + γ}), where t=(T/(T{sub C}))−1 refers to the reduced temperature, f{sub ±} is the scaling function above (+)/below (−) T{sub C}. The β values for Pr{sub 1−x}Ba{sub x}MnO{sub 3} (x = 0.13 and 0.23) are between β = 0.365 (3D Heisenberg exponent) and β = 0.5 (mean-field exponent), whereas γ values are fairly close to γ = 1.386. This reveals long- and short-range order coexisting in Pr{sub 1−x}Ba{sub x}MnO{sub 3}.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2022

Chemical separation of 146 Sm for half-life determination

Here, although methods for the chemical separation of samarium from a rock matrix are well established, chemical separation of samarium from non-natural isotopic impurities for the purpose of 146 Sm half-life measurement requires modifications to these procedures, as well as additional checks for effective separation. This work describes the chemical purification procedures associated with the 146 Sm source and the results from gamma spectroscopy. The purification procedure allowed for the quantitative determination of the number of 146Sm atoms using a modified isotope dilution technique. Alpha-decay counting of the sample will be applied in the future to determine the half-life of 146 Sm.

146Sm↗
DOE OSTI2016

Spatial Modeling of Geometallurgical Properties: Techniques and a Case Study

High-resolution spatial numerical models of metallurgical properties constrained by geological controls and more extensively by measured grade and geomechanical properties constitute an important part of geometallurgy. Geostatistical and other numerical techniques are adapted and developed to construct these high-resolution models accounting for all available data. Important issues that must be addressed include unequal sampling of the metallurgical properties versus grade assays, measurements at different scale, and complex nonlinear averaging of many metallurgical parameters. This paper establishes techniques to address each of these issues with the required implementation details and also demonstrates geometallurgical mineral deposit characterization for a copper–molybdenum deposit in South America. High-resolution models of grades and comminution indices are constructed, checked, and are rigorously validated. The workflow demonstrated in this case study is applicable to many other deposit types.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Capabilities of multivariate Bayesian inference toward seismic hazard assessment

Multivariate Bayesian analysis can bring significant benefits to seismic hazard analysis: Its multivariate feature enables computing scalar and vector hazard without making any approximations; Correlations between intensity measures are implicitly modeled, permitting direct simulation of ground motion selection tools such as the conditional mean spectrum and the generalized conditioning intensity measure; and Its updating feature enables a seamless integration of new ground motion data into the hazard results. Here, we first develop a multivariate Bayesian ground motion model through the NGA-West2 database. The model functional form considers fault-type, magnitude, and distance dependencies, and also the linear and the rock intensity dependent site response. We use a hybrid Markov Chain Monte Carlo sampling to perform Bayesian inference consisting of Gibbs step and a multilevel Metropolis-Hastings step. We then perform several checks on the model and note that its performance is satisfactory. Finally, we illustrate the merits of this multivariate Bayesian analysis, which include: ground motion model updating with ground motion data recorded in the last four years not part of the NGA-West2 database; computation of scalar and vector seismic hazard using the un-updated and updated ground motion models for Los Angeles, CA; and simulation of the conditional mean spectrum under scalar and vector IM conditioning while accounting for different sources of aleatoric and epistemic uncertainties.

58 GEOSCIENCES↗