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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 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

Superconducting kinetic inductance photon detectors.

We are investigating a novel superconducting detector and readout method that could lead to photon counting, energy resolving focal plane arrays. This concept is intrinsically different from STJ and TES detectors, and in principle could deliver large pixel counts, high sensitivity, and Fano-limited spectral resolution in the ptical/UV/X-ray bands. The readout uses the monotonic relation between the kinetic surface inductance L***subs***, of a superconductor and the density of quasiparticles n, which holds even at temperatures far below T***subc***. This allows a sensitive readout of the number of excess quasiparticles in the detector by monitoring the transmission phase of a resonant circuit. The most intriguing aspect of this concept is that passive frequency multiplexing could be used to read out ~ l0***super4*** detectors with a single HEMT amplifier. Single x-ray events have been observed in prototype detectors.

kinetic↗
NASA NTRSDate not supplied

Consolidation of Braided Carbon Fiber/ Thermoplastic Tubes by Induction Heating

Thermoplastic composites have experienced renewed enthusiasm within the U.S. aerospace industry, due in part to opportunities for rapidly manufacturing large structures. Unlike the lengthy cure cycles required by thermosets, the thermoplastic matrix prepreg requires only heat and pressure to consolidate consecutive layers of material; with sufficient inter-ply contact time to develop a strong interface. The manufacturing requirements for thermoplastics provide manufacturing flexibility and of particular interest are in-situ consolidation processes; i.e consolidation during layup on a tool. In-situ consolidation removes the time-consuming and costly secondary processing step of autoclave or press consolidation. Process variables which contribute to laminate quality include temperature, heat transfer, inter-ply contact time, and consolidation pressure. Most of the work to date related to in-situ consolidation has been in conjunction with automated fiber placement (AFP), where prepreg tows are consolidated when placed on the tool. Considering this process for a braided structure adds complexity relative to AFP due to the rapid lay-down rate of the braider and simultaneous placement of a multiple prepreg tows. Processes considered for consolidation during AFP could not be applied to a braided part. Alternatively, a fully braided preform could be consolidated on the tool using well established thermoplastic welding techniques. The goal of this effort was to evaluate the effectiveness of induction welding to consolidate braided carbon fiber/thermoplastic composite tubes up to eight plies in thickness. The manufacturing process, thermal characterization, and initial mechanical property data of the consolidated tubes are reported.

In-situ consolidation, induction heating/welding, ↗
NASA NTRS2024

Development of a High Frequency Class-A Amplifier for High Temperature Wireless Microsystems based on a Silicon Carbide Static Induction Transistor

Next generation gas turbine engine health monitoring for high performance jet engine-powered aircraft will incorporate integrated microelectronic sensors specifically designed to enhance aircraft functionality, engine efficiency, and safety. Temperature, air flow and pressure associated with the gas path as well as emissions from the engine correlate to the state of the combustor and other engine health conditions. Monitoring these parameters accurately requires positioning electronic sensors in the hot zone of the gas turbine engine, which exposes them to temperatures in excess of 400ºC. At these temperatures, signal amplification is needed at the transducer level to distinguish the desired measured signal from the significant electronic noise generated by the harsh environment. In this presentation, we report on the simulation, development, fabrication, and testing on a high temperature Class-A amplifier which utilizes a 4H-SiC Static Induction Transistor (SIT) as the active device and input/output matching and DC bias networks comprised of thin-film spiral inductors, metal-insulator-metal capacitors, and thick film chip resistors. A small signal model that emulates the operation of the 4H-SiC SIT from 25 to 400ºC, with an emphasis on operation at 400οC, was utilized. Measurements were performed from 25 to 400ºC to generate current-voltage curves, capacitive transistor characteristics and high frequency scattering parameters (S-parameters). The measured data was used to extrapolate the transconductance, gm, as a function of temperature for model development. Circuit simulation tools were used to generate S-parameters, which were compared to the measured values. At 400οC, a maximum difference between measured and simulated S-parameters for frequencies from 20 to 100 MHz were 3.84%, 0.68%, 10.61%, and 3.26% for S21, S12, S11, and S22, respectively. The average transit frequency, ft, was calculated from measured values to be 197.8 MHz, while the simulated value from the model was found to be 200 MHz. The Amplifier’s S-parameters were recorded at 20-100 MHz over a temperature range of 25-400ºC and show a gain of approximately 15.8 and 5.80 dBm at 25 and 400ºC, respectively. The input and output reflection coefficients at 50 MHz and 400ºC were -18.5 and -15.2 dB, respectively. The noise figure and phase noise were measured over the temperature range of 25-400ºC and recorded. The noise figure increased 21% at 50 MHz over the temperature range, while the 1 kHz offset of the phase noise remained below -110 dB. The stability factor, K, calculated with measured and simulated data demonstrates unconditional stability over the frequency range at 400ºC. Lastly, the 1-dB compression point was measured at 50 MHz and 400ºC with an approximated output of 9.5 dBm.

SiC↗
DOE OSTI2016

Induction coupled thermomagnetic processing: A disruptive technology

Here, one of the major goals of the U.S. Department of Energy (DoE) is to achieve energy savings with a corresponding reduction in the carbon footprint. With this in mind, the DoE sponsored the Induction Coupled Thermomagnetic Processing (ITMP) project with major partners Eaton Corp., Ajax Tocco Magnethermic, and Oak Ridge National Laboratory (ORNL) to evaluate the viability of processing metals in a strong magnetic field.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2019

Impedance-Based Prediction of SSR-Generated Harmonics in Doubly-Fed Induction Generators: Preprint

Doubly-fed induction generators (DFIGs) are prone to subsynchronous resonance (SSR) with series-compensated transmission lines and experiencing SSR-generated harmonics of wide-ranging magnitudes. This paper presents a large-signal impedance-based approach for the prediction of the magnitude of SSR-generated harmonics in DFIGs. Note that the large-signal impedance of a network shows the variation in its impedance response with the magnitude of perturbation at its terminals. It is discovered in this paper that the impedance of a series-compensated transmission line starts changing with the magnitude of SSR because of the metal oxide varistor (MOV) based protection of series capacitors in the line. The changing line impedance locks the growth of SSR beyond a certain point, where the DFIG forms a limit cycle mode and emits harmonics at the SSR frequency. The discovered role of the protection of series-capacitors in SSR not only enables the prediction of the SSR-generated harmonics but it can also be used for the timely detection of an SSR event to avoid system disruption and sudden loss of a bulk generation. The large-signal impedance-based prediction of SSR-generated harmonics in DFIG-based wind and hydro generators is demonstrated using numerical simulations of a 2.5-MW, 690-V DFIG supplying to a series-compensated transmission line.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2021

Data-Driven Adaptive Damping Controller for Wind Power Plants with Doubly-Fed Induction Generators: Preprint

This paper presents an adaptive damping controller for wind power plants in which the turbines are equipped with doubly-fed induction generators. The controller is designed to respond to an input control signal that is triggered according to the system operating conditions. A processing unit continuously estimates the electromechanical modes of oscillation based on real-time streaming data acquired from a phasor measurement unit that is strategically positioned on the grid. The decision to trigger (or not trigger) the control signal is automatic, based on the relative damping of the dominant mode. The modes are estimated using the dynamic mode decomposition algorithm with time-delay embedding. Numerical simulations performed on the two-area system demonstrate that the proposed controller enhances the rotor angle stability for both small-signal and large disturbances, and is adaptive to changing grid conditions.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2015

Control of vacuum induction brazing system for sealing of instrumentation feed-through

The integrity of instrumentation cables is an important performance parameter in addition to the sealing performance in the brazing process. An accurate brazing control was developed for the brazing of the instrumentation feed-through in the vacuum induction brazing system in this paper. The experimental results show that the accurate brazing temperature control performance is achieved by the developed control scheme. Consequently, the sealing performances of the instrumentation feed-through and the integrities of the instrumentation cables were satisfied after brazing. (authors)

42 ENGINEERING↗
DOE OSTI2018

Schottky Junction Vertical Channel GaN Static Induction Transistor with a Sub‐Micrometer Fin Width

Abstract GaN‐based vertical transistors have demonstrated its excellent properties for high‐power and high‐frequency electronic devices. This work introduces a GaN‐based static induction transistor (SIT) which is another form of vertical GaN transistors without requiring any p ‐type GaN and gate dielectrics for its operation. Processing strategy to generate the GaN SIT with a sub‐micrometer fin width involves photoresist (PR)‐assisted planarization with an understanding of dry etch parameters for the planar PR surface. The efficacy of this process is demonstrated by the device's triode‐like output characteristics with high current density (0.65 kA cm −2 ) and low ON resistance (1.48 mΩ cm 2 ) at 1 V of drain voltage. In addition, the electrical properties such as current density and modulation are examined depending on the fin width of GaN SIT. The result reveals that the size reduction in the GaN SIT utilizing the sub‐micrometer fin as a channel could increase the current modulation, but it could decrease the current density because of the raised potential minima due to the depletion region overlap. It is believed that the GaN SIT demonstrating high blocking voltage and low ON resistance would present a very promising class of transistor for next‐generation high‐power and high‐frequency electronics.

Chun, Jaeyi↗
DOE OSTI2023

Induction and Stabilization of Columnar Mesophases in Fluorinated Polycyclic Aromatic Hydrocarbons by Arene‐Perfluoroarene Interactions

Abstract The straightforward synthesis of several Fluorinated Polycyclic Aromatic Hydrocarbons by the efficient, transition‐metal‐free, arene fluorine nucleophilic substitution reaction is described, and the full investigation of their liquid crystalline and optical properties reported. The key precursors for this study, i. e. 2,2’‐dilithio‐4,4′,5,5′‐tetraalkoxy‐1,1’‐biphenyl derivatives, were obtained in two steps from the highly selective Scholl oxidative homo‐coupling of 3,4‐dialkoxy‐1‐bromobenzene, followed by quantitative double‐lithiation. In situ room temperature nucleophilic annulation with either perfluorobenzene or perfluoronaphthalene leads to 1,2,3,4‐tetrafluoro‐6,7,10,11‐tetraalkxoytriphenylenes and 9,10,11,12,13,14‐hexafluoro‐2,3,6,7‐tetraalkoxybenzo[f]tetraphenes, respectively, in good yields. Exploiting the same strategy, subsequent double annulations resulted in the formation of 9,18‐difluoro‐2,3,6,7,11,12,15,16‐octa(alkoxy)tribenzo[f,k,m]tetraphenes and 9,10,19,20‐tetrafluoro‐2,3,6,7,12,13,16,17‐octakis(hexyloxy)tetrabenzo[a,c,j,l]tetracenes, respectively. Despite the presence of only four alkoxy chains, the polar “Janus” mesogens display a columnar hexagonal mesophase over broad temperature ranges, with higher mesophase stability than the archetypical 2,3,6,7,10,11‐hexa(alkoxy)triphenylenes and their hydrogenated counterparts. The improvement or induction of mesomorphism is attributed to efficient antiparallel face‐to‐face π‐stacking driven by the establishment of non‐covalent perfluoroarene‐arene intermolecular interactions. The larger lipophilic discotic π‐extended compounds also exhibit columnar mesomorphism, over similar temperature ranges and stability than their hydrogenated homologs. Finally, these fluorinated molecules form stringy gels in various solvents, and show interesting solvatochromic emission properties in solution as well as strong emission in thin films and gels.

Chemistry↗
DOE OSTI2026

Simultaneous Determination of Halogens and Metals in Waste Plastic Pyrolysis Oil by Inductively Coupled Plasma Mass Spectrometry

A major barrier to integrating pyrolysis-derived oil into conventional refinery technology is the presence of impurities, particularly halogens and metals, that can deactivate catalysts. This study presents a novel, cost-effective approach for the simultaneous analysis of a subset of halogens, metals, nonmetals, and metalloids in complex, industrially relevant distilled pyrolysis oil samples, this was previously achievable only through multiple techniques. Excellent results were obtained using a widely accessible inductively coupled plasma mass spectrometry (ICP-MS) method with helium gas mode and standard laboratory consumables, enabling high-throughput analysis and efficient evaluation of adsorbent performance. Sample preparation is straightforward, requiring only dilution in a compatible matrix, and provides accurate and precise quantification, with 75%–137% spike recovery for Be, Ti, V, Cr, Fe, Ni, Co, Cu, As, Se, Mo, Cd, Sb, Tl, and Pb, and 62%–65% spike recovery for Cl and 109%–133% spike recovery for Br. Additionally, an enhanced version of the method using ICP-MS/MS and hydrogen gas is described, which has higher accuracy with 69%–112% spike recovery for Be, B, Ti, V, Fe, Co, Ni, Cu, As, Se, Mo, Cd, Sb, Tl, and Pb, with 85%–102% spike recovery for Cl and 63%–93% spike recovery for Br. Helium mode detection limits for industrially relevant elements (V, Fe, Ni, Cu, As, and Pb) are less than 1.7 µg/kg, and less than 0.2 mg/kg for Br and Cl. Furthermore, this methodology facilitates rapid systematic evaluation of adsorption capacities of materials under time-on-stream conditions and supports robust comparisons across diverse operating environments.

Lazarcik, James [University of Wisconsin-Madison, ↗
DOE OSTI2017

Ion Energy and Angular Distribution in Biased Inductively Coupled Ar/O 2 Discharges by Using a Hybrid Model

In this work, a global bulk plasma model coupled bi‐directionally with a Monte‐Carlo/fluid sheath model was developed for electronegative inductive discharges, to explore the ion energy function (IEDF) and angular distributions function (IADF) bombarding an rf‐biased electrode. At low bias voltage, the IEDF of shows a single energy peak that transforms into a bimodal distribution with increasing bias voltage. The IEDFs of and are always bimodal. The ion energy peak separation width largely depends on the ion masses. The IADFs are affected by the bias voltage, pressures and coil powers. The results at different coil powers indicate the importance of considering the collisions induced by atoms, especially in a a molecular gas.

Wen, De‐Qi↗
DOE OSTI2024

A preliminary investigation into the feasibility of laser ablation U–Pb isotope ratio measurement via all‐faraday cup detection with 10 11 ‐ and 10 13 ‐Ω amplifiers on the Neoma multicollector‐inductively coupled plasma‐mass spectrometer

Rationale Signal detection for uranium–lead (U–Pb) dating of zircon is typically performed via ion counters. Here, we develop a preliminary understanding of the strengths and limitations of faraday‐cup‐based detection. Methods A suite of zircon reference materials and the NIST‐610 glass were sampled using laser ablation followed by U–Pb isotope ratio measurement on a Neoma multicollector‐inductively coupled plasma‐mass spectrometer. Results We were able to produce geologically accurate 207 Pb/ 206 Pb, 206 Pb/ 238 U, and 207 Pb/ 235 U ratios for the NIST‐610 glass and the zircon standards, with ages ranging from ~2.5 Ga to ~337 Ma (TanBrown A, Oracle, 91550, Mud Tank, Temora, and Plešovice). Two of the younger zircon standards examined (94‐35, ~55.6 Ma, and Fish Canyon, 28.6 Ma) yielded accurate 206 Pb/ 238 U but not 207 Pb/ 235 U or 207 Pb/ 206 Pb ratios, whereas the youngest zircon standard (Penglai, ~4.4 Ma) failed for all three ratios of interest. The accuracy and precision of the all‐faraday method are directly tied to signal intensity, with reliable data capable of being produced even when both isotopes in a ratio have signals below ~0.001 V (equivalent to ~62 500 cps on an ion counter). Conclusion The all‐faraday cup multicollection method provides sufficient sensitivity to obtain geologically meaningful U–Pb data, with possible advantages being that laser pit depth‐dependent changes in the observed interelemental fractionation behavior may be easier to correct using a static collector configuration compared to when the ion beam is swept across a single detector while also removing the need for an interdetector‐type calibration. Further work is needed to refine the all‐faraday cup method (e.g., application of background subtraction and common Pb corrections, outlier removal, and interelement as well as down‐hole fractionation corrections), but our initial results demonstrate that the faraday detector method has sufficient sensitivity to warrant further study.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

Energy and Emission Prediction for Mixed-Vehicle Transit Fleets Using Multi-task and Inductive Transfer Learning

Public transit agencies are focused on making their fixed-line bus systems more energy efficient by introducing electric (EV) and hybrid (HV) vehicles to their fleets. However, because of the high upfront cost of these vehicles, most agencies are tasked with managing a mixed-fleet of internal combustion vehicles (ICEVs), EVs, and HVs. In managing mixed-fleets, agencies require accurate predictions of energy use for optimizing the assignment of vehicles to transit routes, scheduling charging, and ensuring that emission standards are met. The current state-of-the-art is to develop separate neural network models to predict energy consumption for each vehicle class. Although different vehicle classes’ energy consumption depends on a varied set of covariates, we hypothesize that there are broader generalizable patterns that govern energy consumption and emissions. In this paper, we seek to extract these patterns to aid learning to address two problems faced by transit agencies. First, in the case of a transit agency which operates many ICEVs, HVs, and EVs, we use multi-task learning (MTL) to improve accuracy of forecasting energy consumption. Second, in the case where there is a significant variation in vehicles in each category, we use inductive transfer learning (ITL) to improve predictive accuracy for vehicle class models with insufficient data. As this work is to be deployed by our partner agency, we also provide an online pipeline for joining the various sensor streams for fixed-line transit energy prediction. Here, we find that our approach outperforms vehicle-specific baselines in both the MTL and ITL settings.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2019

Cell cycle arrest and induction of apoptosis of newly synthesized pyranoquinoline derivatives under microwave irradiation

A set of 2-amino-4-aryl-4H-pyrano[3,2-h]quinoline-3-carbonitrile derivatives were prepared via a one-pot, three-component condensation reaction between the substituted hydroxyquinoline derivatives, some aryl and/or hetaryl aldehydes, and malononitrile in an ethanol/piperidine solution in a microwave irradiation environment. The structure of the prepared compounds was instituted on the foundations of their spectral data: IR, {sup 1}H NMR, {sup 13}C NMR, and MS. Four human cancer cell lines, MCF-7, HCT-116, HepG-2, and A549 were utilized to evaluate the antiproliferative properties of the target compounds in comparison to the positive controls, Vinblastine and Colchicine using the MTT viability assay. The cell cycle arrest behavior, detected by propidium iodide as well as the apoptosis induction, which was monitored by the flow cytometer, using the Annexin V-FITC kits, was investigated. The results illustrated that the potent cytotoxic compounds induce cell cycle arrest at the G2/M phases and trigger apoptosis in the different tested cancer cells. Finally, the structure−activity relationship (SAR) study showcases the substitution of some specific groups at the 4-, 6-, and 9-positions in the prepared 2-amino-4H-pyrano[3,2-h]quinoline derivatives, which indicates that the lipophilicity manipulates the ability of these moieties against the diverse cell lines.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Climate controls over ecosystem metabolism: insights from a fifteen-year inductive artificial neural network synthesis for a subalpine forest

Eddy covariance (EC) datasets have provided insight into climate determinants of net ecosystem productivity (NEP) and evapotranspiration (ET) in natural ecosystems for decades, but most EC studies were published in serial fashion such that one study’s result became the following study’s hypothesis. Our approach reflects the hypothetico-deductive process by focusing on previously derived hypotheses. A synthesis of this type of sequential inference reiterates subjective biases and may amplify past assumptions about the role, and relative importance, of cont rols over ecosystem metabolism. Long-term EC datasets facilitate an alternative approach to synthesis: the use of inductive data-based analyses to re-examine past deductive studies of the same ecosystem. Here we examined the seasonal climate determinants of NEP and ET by analyzing a 15-year EC time-series from a subalpine forest using an ensemble of Artificial Neural Networks (ANNs) at the half-day (daytime/nighttime) time-step. We also extracted relative rankings of climate drivers and driver–response relationships directly from the dataset with minimal a priori assumptions. The ANN analysis revealed temperature variables as primary climate drivers of NEP and daytime ET, when all seasons are considered, consistent with the assembly of past studies. New relations uncovered by the ANN approach include the role of soil moisture in driving daytime NEP during the snowmelt period, the nonlinear response of NEP to temperature across seasons, and the low relevance of summer rainfall for NEP or ET at the same daytime/nighttime time step. These new results offer a more complete perspective of climate–ecosystem interactions at this site than traditional deductive analyses alone.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Irradiated FA Structural Materials Conditioning by Induction-Slag Remelting in a Cold Crucible

A method of managing one type of radwaste forming during BREST-300 reactor operation – the structural materials of FA – is described. In the module developed for reprocessing, the fissile materials losses together with all forms of waste must not exceed 0.1% of the initial amount, in connection with which the maximum admissible content of facade materials and structural materials sent into long-term storage must not exceed 0.001% by weight. Only the plutonium content may reach 0.015% by weight, which makes it necessary to perform additional purification and return fissile materials into the nuclear fuel cycle. A method of reprocessing the structural materials of irradiated fuel elements is proposed on the basis of induction-slag remelting in a cold crucible, which makes it possible to conduct purification to the desired index value. The operating regime of the melting unit and the qualitative composition of the employed flux that make it possible to reach the required level of purification by removal of fissile materials are described.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗