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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 OSTI2019

Basic Oxygen Furnace: Assessment of Recent Physicochemical Models

Modeling of the basic oxygen furnace (BOF) process, both for online monitoring and fundamental research, has gained importance in steelmaking industry over the past few decades. Especially models integrating fundamental physicochemical relations are appealing. Even though a vast amount of these kind of models and submodels can be found in the literature, no recent review paper is available which thoroughly discusses the most up-to-date BOF modeling methods. This study aims to do so. In the introductory chapters, an overview is given on the assumptions and models for underlying BOF phenomena, which are frequently used in the BOF models and submodels. Focus was put on six models with emphasis on the chemical aspect of the BOF process. For each model, its assumptions are given and subsequently evaluated, highlighting both their strengths and limitations. The six different models are also compared with each other. Finally, opportunities for future research are discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Comparative Study of Zinc Cold-Spray Coating and Pre-treatments for Magnesium Alloys

Magnesium (Mg) alloys are appealing for automotive lightweighting owing to their high specific strength. However, their susceptibility to corrosion in harsh environments remains a major challenge. Conventional industrial pre-treatment coatings, including zinc phosphate, chromate conversion, and non-chromate conversion, often exhibit discontinuities and microcracks, leading to localized corrosion near fasteners and parting lines. Here, this study investigates cold-sprayed zinc (Zn) coatings as a novel pre-treatment alternative for high-pressure die cast (HPDC) AZ91 Mg alloys, demonstrating significant improvements in wear and corrosion performance. Cold spray produces uniform and robust coatings, reducing wear rate by over 50% and reducing corrosion rate by over 99.3%, as measured by evolved hydrogen release, compared to traditional pre-treatments. Multimodal corrosion testing reveals that Zn cold-spray coatings form a protective layer during exposure, minimizing general and filiform corrosion, and exhibiting corrosion potential (E corr ) that is nobler by ~ 400 mV than the surfaces of both pre-treated and uncoated AZ91. Scalability of cold spray for selective application around multimaterial joints further strengthens their industrial viability. This work establishes Zn cold-spray coatings as highly effective pre-treatment solutions for the advancement of corrosion resistant Mg alloy components in automotive applications.

multimodal corrosion↗
DOE OSTI2019

Non-invasive Risk Stratification for Coronary Artery Disease: Is It Time for Subclassifications?

Purpose of Review: Coronary artery disease (CAD) is the leading contributor to cardiovascular disease; it is the most prevalent non-communicable disease globally and has high morbidity, mortality and health care cost. Risk stratification is defined as prevention or containment of disease prior to it occurring or progressing, and non-invasive surrogates include history, examination, biomarkers and non-invasive imaging. This review aims to highlight advancement in current diagnostic strategies and explores gaps for CAD secondary to atherosclerosis and non-obstructive vascular diseases. Recent Findings: Cardiac risk scores have largely proven inadequate in risk stratifying heterogeneous patient populations. Greater emphasis should also be provided to posttest risk stratification. Non-invasive imaging with MRI is the most accurate but least cost efficacious presently due to availability and expertise. Echocardiography and nuclear imaging have good accuracy, but radiation limits the latter. Novel echocardiographic technologies may increase its appeal. Cardiac CT angiography is increasingly promising. Summary: Non-invasive and minimally invasive imaging has significantly influenced the cost-efficacy trajectory of coronary artery disease diagnosis and management. Recent studies suggest that future guidelines will incorporate more subclassifications from the findings of these novel technologies and for more diverse patient demographics.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Fluorescence in situ hybridization in 1 mL of selective urine for the detection of upper tract urothelial carcinoma: a feasibility study

Kidney-sparing surgery of upper tract urothelial carcinoma (UTUC) requires a stringent follow-up with frequent ureteroscopies. Triage testing could reduce the number of follow-up ureteroscopies and hence minimize the invasiveness of follow-up. The use of urine-based markers for triage seems appealing but should be feasible with selective urine from outpatient cystoscopy to maximize the reduction of invasiveness. In this study, the feasibility of UroVysion{sup ®} fluorescence in situ hybridization (FISH) for the detection of UTUC in 1 mL of selective urine is investigated. Ten consecutive patients with biopsy-proven UTUC and five patients with negative diagnostic ureteroscopy findings were included in this case-control study. During ureteroscopy, 1 mL of selective urine was collected passively with a ureteral splint for Urovysion® FISH. The FISH rater was blinded to any clinical information. The results of FISH were compared to the findings of concomitantly collected selective urine cytology and the patients’ UTUC status. FISH was feasible in all samples with a sensitivity of 90% and a specificity of 80% for UTUC. In comparison, selective cytology resulted in a diagnostic yield of 87% with a sensitivity of 80% and a specificity of 67%. In conclusion, UTUC detection is feasible with FISH in 1 mL of passively collected selective urine. Thus from a technical point of view, FISH could be used as an outpatient triage test to decide if follow-up ureteroscopy is necessary after kidney-sparing surgery of UTUC. Evaluation of the diagnostic accuracy of FISH for the suggested pathway deserves further attention.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

My warranty has expired: I need to be retested

The concept of warranty period, the duration of time during which the patient’s risk remains low, is appealing. However, some points remain to be resolved before its translation in the clinical arena. Methodological issues should be standardized in order to compare the results of studies in different patient populations. Also, the definition of a “normal” study should always take into consideration the history of prior revascularization, the achieved level of exercise, and the stressor used. The promise of warranty can be questioned by the patient’s baseline demographic and clinical characteristics and may also be influenced by life-style modification in the course of the follow-up. The “warranty period” concept should shift from data reflecting the time to a cardiac event to the development of ischemia, given an opportunity for intervention before a cardiac event occurs. In this context, clarify the role of serial imaging can be extremely useful, in particular to evaluate if and when retesting a patient after a normal scan.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Interrogating Proton Affinities of Organophosphonate Species Via Atmospheric Flow Tube Mass Spectrometry and Computational Methods

Within trace vapor analysis in environmental monitoring, defense, and industry, atmospheric flow tube mass spectrometry (AFT-MS) can fill a role that incorporates non-contact vapor analysis with the selectivity and low detection limits of mass spectrometry. AFT-MS has been applied to quantitating certain explosives by selective clustering with nitrate and more recently applied to detecting tributyl phosphate and dimethyl methylphosphonate as protonated species. Developing AFT-MS methods for organophosphorus species is appealing, given that this class of compounds includes a range of pollutants, chemical warfare agent (CWA) simulants, and CWA degradation products. A key aspect of targeting organophosphorus analytes has included the use of dopant ion chemistry to form adducts that impart additional analytical selectivity. The assessment of potential dopant molecules suited to enhance detection of these compounds is hindered by few published ion thermochemical properties for organophosphorus species, such as proton affinity, which can be used for approximating proton-bound dimer bond strength. As a preliminary investigation for the progression of sensing methods involving AFT-MS, we have applied both the extended kinetic method and computational approaches to eight organophosphorus CWA simulants to determine their respective gas-phase proton affinities. Notable observed trends, supported by computational efforts, include an increase in proton affinity as the alkyl chain lengths on the phosphonates increased. .

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2012

Epidermal Differential Impedance Sensor for Conformal Skin Hydration Monitoring

We present the design and use of an ultrathin, stretchable sensor system capable of conformal lamination onto the skin, for precision measurement and spatial mapping of levels of hydration. This device, which we refer to as a class of ‘epidermal electronics’ due to its ‘skin-like’ construction and mode of intimate integration with the body, contains miniaturized arrays of impedance-measurement electrodes arranged in a differential configuration to compensate for common-mode disturbances. Experimental results obtained with different frequencies and sensor geometries demonstrate excellent precision and accuracy, as benchmarked against conventional, commercial devices. The reversible, non-invasive soft contact of this device with the skin makes its operation appealing for applications ranging from skin care, to athletic monitoring to health/wellness assessment.

47 OTHER INSTRUMENTATION↗
DOE OSTI2018

Whole Body MRI: Non-oncological Musculoskeletal Applications

Purpose of the Review: Whole-body MRI is an emerging imaging technique on continuous evolution, used in many oncologic indications and introduced more recently in rheumatologic and systemic disorders. In this article, we review the recent musculoskeletal applications of this technique outside the field of cancer. Recent Findings: Whole-body MRI, with its high sensitivity to bone marrow and soft-tissue alterations, and ability of extensive body coverage, is progressively regarded as an effective and powerful imaging tool for the detection, staging, and monitoring under treatment of many rheumatic diseases and systemic pathologies affecting the musculoskeletal system. Disease specific imaging protocols have been designed. Summary: Whole-body MRI is an appealing, non-irradiating tool emerging in musculoskeletal imaging. It is becoming the imaging of choice in several non-oncologic indications, and its application field is on continuous expansion.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Compatible meshfree discretization of surface PDEs

Meshfree discretization of surface partial differential equations is appealing, due to their ability to naturally adapt to deforming motion of the underlying manifold. In this work, we consider an existing scheme proposed by Liang et al. reinterpreted in the context of generalized moving least squares (GMLS), showing that existing numerical analysis from the GMLS literature applies to their scheme. With this interpretation, their approach may then be unified with recent work developing compatible meshfree discretizations for the div-grad problem in R d . Informally, this is analogous to an extension of collocated finite differences to staggered finite difference methods, but in the manifold setting and with unstructured nodal data. In this way, we obtain a compatible meshfree discretization of elliptic problems on manifolds which is naturally stable for problems with material interfaces, without the need to introduce numerical dissipation or local enrichment near the interface. As a result, we provide convergence studies illustrating the high-order convergence and stability of the approach for manufactured solutions and for an adaptation of the classical five-strip benchmark to a cylindrical manifold.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Coupling of Adhesion and Anti-Freezing Properties in Hydrogel Electrolytes for Low-Temperature Aqueous-Based Hybrid Capacitors

Solid-state zinc-ion capacitors are emerging as promising candidates for large-scale energy storage owing to improved safety, mechanical and thermal stability and easy-to-direct stacking. Hydrogel electrolytes are appealing solid-state electrolytes because of eco-friendliness, high conductivity and intrinsic flexibility. However, the electrolyte/electrode interfacial contact and anti-freezing properties of current hydrogel electrolytes are still challenging for practical applications of zinc-ion capacitors. Here, we report a class of hydrogel electrolytes that couple high interfacial adhesion and anti-freezing performance. The synergy of tough hydrogel matrix and chemical anchorage enables a well-adhered interface between hydrogel electrolyte and electrode. Meanwhile, the cooperative solvation of ZnCl 2 and LiCl hybrid salts renders the hydrogel electrolyte high ionic conductivity and mechanical elasticity simultaneously at low temperatures. More significantly, the Zn||carbon nanotubes hybrid capacitor based on this hydrogel electrolyte exhibits low-temperature capacitive performance, delivering high-energy density of 39 Wh kg –1 at –60 °C with capacity retention of 98.7% over 10,000 cycles. With the benefits of the well-adhered electrolyte/electrode interface and the anti-freezing hydrogel electrolyte, the Zn/Li hybrid capacitor is able to accommodate dynamic deformations and function well under 1000 tension cycles even at –60 °C. This work provides a powerful strategy for enabling stable operation of low-temperature zinc-ion capacitors.

25 ENERGY STORAGE↗
DOE OSTI2021

Progress of Nanotechnology for Lithium-Sulfur Batteries

Lithium-Sulfur (Li-S) battery has been proposed and investigated since the 1960s as an effective energy storage device via reversible electrochemical reactions. As the fast development and commercialization of Li-ion battery (LIB) technology kept moving forward, no breakthroughs have been attained to solve critical technical issues facing Li-S batteries during the following decades. In the year 2000s, Li-S batteries reattracted significant interests in the research field owing to their low-cost advantages, high theoretical specific energy of 2600 Wh kg -1 , which is at least 3 times higher than the current LIB technology. The low-cost and high abundance of sulfur (i.e., the cathode active material), make Li-S batteries more appealing than LIBs given the fact that the latter use critical materials such as cobalt and nickel in the manufacturing of the cathodes. Moreover, the high-energy and low-cost features make the Li-S battery a promising energy storage technology in practical applications such as portable devices, electric vehicles, and grid storage when coupled with the harvesting of solar or wind renewable energies. For example, since 2007, SION Power Corporation (Tucson, USA) and Oxis Energy (UK) made progress towards the commercialization of Li-S batteries with products showing specific energies over 350 Wh kg -1 for powering electric vehicles. To be on a par with the current LIB technology, the ultimate goal of achieving 500 Wh kg -1 for Li-S battery will make it more competitive for widespread commercialization.

Li, Mengya↗
DOE OSTI2021

Deep convolutional autoencoders as generic feature extractors in seismological applications

The idea of using a deep autoencoder to encode seismic waveform features and then use them in different seismological applications is appealing. In this paper, we designed tests to evaluate this idea of using autoencoders as feature extractors for different seismological applications, such as event discrimination (i.e., earthquake vs. noise waveforms, earthquake vs. explosion waveforms), and phase picking. These tests involve training an autoencoder, either undercomplete or overcomplete, on a large amount of earthquake waveforms, and then using the trained encoder as a feature extractor with subsequent application layers (either a fully connected layer, or a convolutional layer plus a fully connected layer) to make the decision. By comparing the performance of these newly designed models against the baseline models trained from scratch, we conclude that the autoencoder feature extractor approach may only outperform the baseline under certain conditions, such as when the target problems require features that are similar to the autoencoder encoded features, when a relatively small amount of training data is available, and when certain model structures and training strategies are utilized. The model structure that works best in all these tests is an overcomplete autoencoder with a convolutional layer and a fully connected layer to make the estimation.

58 GEOSCIENCES↗
DOE OSTI2014

Dissipative Bohmian mechanics within the Caldirola–Kanai framework: A trajectory analysis of wave-packet dynamics in viscid media

Classical viscid media are quite common in our everyday life. However, we are not used to find such media in quantum mechanics, and much less to analyze their effects on the dynamics of quantum systems. In this regard, the Caldirola–Kanai time-dependent Hamiltonian constitutes an appealing model, accounting for friction without including environmental fluctuations (as it happens, for example, with quantum Brownian motion). Here, a Bohmian analysis of the associated friction dynamics is provided in order to understand how a hypothetical, purely quantum viscid medium would act on a wave packet from a (quantum) hydrodynamic viewpoint. To this purpose, a series of paradigmatic contexts have been chosen, such as the free particle, the motion under the action of a linear potential, the harmonic oscillator, or the superposition of two coherent wave packets. Apart from their analyticity, these examples illustrate interesting emerging behaviors, such as localization by “quantum freezing” or a particular type of quantum–classical correspondence. The reliability of the results analytically determined has been checked by means of numerical simulations, which has served to investigate other problems lacking of such analyticity (e.g., the coherent superpositions). - Highlights: • A dissipative Bohmian approach is developed within the Caldirola–Kanai model. • Some simple yet physically insightful systems are then studied analytically. • Dissipation leads to spatial localization in free-force regimes. • Under the action of linear forces, dissipation leads to uniform motion. • In harmonic potentials, the system decays unavoidable to the well minimum.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Full quantum mechanical analysis of atomic three-grating Mach–Zehnder interferometry

Atomic three-grating Mach–Zehnder interferometry constitutes an important tool to probe fundamental aspects of the quantum theory. There is, however, a remarkable gap in the literature between the oversimplified models and robust numerical simulations considered to describe the corresponding experiments. Consequently, the former usually lead to paradoxical scenarios, such as the wave–particle dual behavior of atoms, while the latter make difficult the data analysis in simple terms. Here these issues are tackled by means of a simple grating working model consisting of evenly-spaced Gaussian slits. As is shown, this model suffices to explore and explain such experiments both analytically and numerically, giving a good account of the full atomic journey inside the interferometer, and hence contributing to make less mystic the physics involved. More specifically, it provides a clear and unambiguous picture of the wavefront splitting that takes place inside the interferometer, illustrating how the momentum along each emerging diffraction order is well defined even though the wave function itself still displays a rather complex shape. To this end, the local transverse momentum is also introduced in this context as a reliable analytical tool. The splitting, apart from being a key issue to understand atomic Mach–Zehnder interferometry, also demonstrates at a fundamental level how wave and particle aspects are always present in the experiment, without incurring in any contradiction or interpretive paradox. On the other hand, at a practical level, the generality and versatility of the model and methodology presented, makes them suitable to attack analogous problems in a simple manner after a convenient tuning. - Highlights: • A simple model is proposed to analyze experiments based on atomic Mach–Zehnder interferometry. • The model can be easily handled both analytically and computationally. • A theoretical analysis based on the combination of the position and momentum representations is considered. • Wave and particle aspects are shown to coexist within the same experiment, thus removing the old wave-corpuscle dichotomy. • A good agreement between numerical simulations and experimental data is found without appealing to best-fit procedures.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

A unified approach to Plasmon–Polariton and Brewster mode dynamics in media with interfacial surface-admittance

In this article we develop an ab-initio formulation for the analysis of certain solutions to the macroscopic Maxwell equations in bulk homogeneous materials that are separated by a planar interface that may sustain field-dependent electric currents induced by a surface admittance tensor. Based on Clemmow’s description of complex inhomogeneous plane time-harmonic waves, a systematic procedure is given that yields particular global solutions in terms of solutions to a system of bivariate polynomial and linear eigen-value equations for a set of six complex dimensionless scalars. This algebraic system is amenable to rapid numerical analysis using Maple or Matlab on a laptop. From the resulting solutions, analytic formulae for the electromagnetic fields can be expressed in terms of values for these six scalars and the electromagnetic phenomenological properties of the bulk media and their interface. We show explicitly how general properties of Surface Plasmon–Polariton (SPP) and Brewster modes follow from this unified viewpoint without appeal to any reflections in a Fresnel formulation. In particular we emphasise that endowing the material interface with (in general) anisotropic admittance properties can lead to new global electromagnetic field characteristics offering new possibilities for the control of surface characteristics by using recent advances in the fabrication of meta-materials. We illustrate our results by showing how a mono-layer of graphene in a normal magneto-static field can be used to construct a tunable meta-surface for SPP generation and how a simple conducting Ohmic interface can be used to excite both transverse electric and transverse magnetic Brewster modes as a function of the interface admittance.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2021

Visually resolving the direct Z-scheme heterojunction in CdS@ZnIn 2 S 4 hollow cubes for photocatalytic evolution of H 2 and H 2 O 2 from pure water

We report the direct Z-scheme heterojunction has been recently emerging as an appealing architecture for photocatalysts design. Its efficiency depends on the interfacial and structural features of the photocatalysts. Herein, the two-dimensional ZnIn 2 S 4 nanosheets are grown on the surface of CdS hollow cubes to construct the CdS@ZnIn 2 S 4 hierarchical hollow photocatalysts with chemically bonded interface. The visualized measurements based on spatial-resolved surface photovoltage spectroscopy, combined with other spectroscopic and simulation investigations, clearly disclose that the CdS@ZnIn 2 S 4 hollow cubes constitute a highly efficient direct Z-scheme system. This accounts for the stoichiometric generation of H 2 and H 2 O 2 from pure water observed for the CdS@ZnIn 2 S 4 sulfide-only photocatalysts under visible light irradiation with an apparent quantum efficiency of 1.63 % at 400 nm. The present work demonstrates an effective protocol to achieve comprehensive insights into the charge transfer route at semiconductor heterojunction, and offers a viable way for constructing efficient sulfide-only photocatalysts for driving water splitting reaction.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗