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At least 145 records · Page 8

All sources NASA NTRS DOE OSTI

DOE OSTI2016

Optical characteristics for capacitively and inductively radio frequency discharge and post-discharge of helium

The optical properties for radiofrequency (RF) post-discharge of pure helium (He) with two different methods as capacitively and inductively have been presented using the modified Boltzmann method in comparison. Optical emission spectroscopy (OES) is often used in the diagnosis of laboratory plasma, such as gas discharge plasma. OES is a very useful method for calculating of the electron temperature in the plasma and the determination of different atoms and molecules. In this study, OES is applied for characterizations of capacitively and inductively RF He plasma at pressures between 0.62 and 2.2 mbar for newly reactor type. Plasmas are generated with an RF power generator at a frequency of 13.56 MHz and output powers of 100, 160, and 200 W. Spectra have been evaluated in the range 200–1200 nm by an optical spectrometer. At low pressure, the main spectral features reported are the wavelengths of the atomic He transitions at 388.87 and 728.13 nm. The atomic emission intensities showed a maximum in inductive system when the pressure is about 0.62 mbar. OES of capacitive discharge and inductive discharge is compared in detail. The transition for 587.56 nm is shown to be increased in time.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

DOE OSTI2019

Optimization of an in Vitro CYP450 Induction Assay Using Cryopreserved Cell Lines

Cytochrome P450 (CYP450) enzymes are responsible for the majority for Phase I metabolism. Induction occurs when a drug increases the rate of CYP450 enzyme production. As a result, the rates of metabolism of subsequent drugs increase, posing concerns for dosing and safety. To further expand the USAMRICD Absorption, Distribution, Metabolism, Excretion, and Toxicity Center of Excellence (ADMET CoE) profiling capabilities, a CYP450 induction assay is being developed using alternative cell lines to primary human hepatocytes to measure changes in gene expression of CYP1A2 and CYP3A4 isoenzymes. Primary human hepatocytes are the gold standard for evaluating P450 induction in vitro ; however, they have inherent limitations such as high costs, fastidious nature, and significant lot‐to‐lot variability. Induction assessments using cryopreserved hepatocytes and two immortalized cell lines, HepaRG and HepatoCells, are being conducted to determine a more robust, cost‐effective alternative model. Each cell line was exposed to the standard inducers rifampicin and omeprazole to assess CYP3A4 and CYP1A2 activity, respectively. Following a 72‐hour incubation period, RNA from the cell cultures was extracted and purified. Fold changes of gene expression were measured using real‐time quantitative PCR (RT‐qPCR). Hepatocytes displayed an average fold change of 92.7 for CYP3A4 and 49.6 for CYP1A2, whereas HepaRG displayed changes of 28.6 and 179.5, respectively. Average values for CYP3A4 and CYP1A2 for HepatoCells were 58.7 and 43.9. Based on the data, HepatoCells most closely mimicked cryopreserved hepatocytes in comparison to HepaRG cells. Additional data on assay parameters and technique optimization will be presented. Support or Funding Information Opinion disclaimer: The views expressed in this abstract are those of the authors and do not reflect the official policy of the Department of the Army, Department of Defense, or the U.S. Government. This project was generously supported in part by an appointment to the Postgraduate Research Participation Program at the U.S. Army Medical Research Institute of Chemical Defense administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the U.S. Department of Energy and U.S. Army Medical Research and Materiel Command. Support is also provided by the Defense Threat Reduction Agency – Joint Science and Technology Office, Medical S&T Division. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .

Lim, Tae Young↗

DOE OSTI2025

Emergent Inductance from Chiral Orbital Currents in a Bulk Ferrimagnet

Here, we report the discovery of a new form of inductance in the bulk ferrimagnet Mn 3 ⁢Si 2 ⁢Te 6 , which features strong spin-orbit coupling, large magnetic anisotropy, and pronounced magnetoelastic interactions. Below its Curie temperature (𝑇 𝐶 ≈ 78 K), Mn 3 ⁢Si 2 ⁢Te 6 hosts chiral orbital currents (COC) that circulate within the crystal lattice and give rise to collective electronic behavior [Control of chiral orbital currents in a colossal magnetoresistance material, Nature (London) 611, 467 (2022).]. By applying a magnetic field along the hard 𝑐 axis and driving the system with low-frequency currents, we uncover a giant inductive response up to millhenry scale, originating from first-order reconfigurations of COC domains. These domains act as coherent mesoscopic inductive elements that resist reversal upon current reduction, producing a large electromotive force and sharply increasing voltage. This emergent inductance defies classical models, occurs without superconductivity or engineered nanostructures, and opens a new frontier in orbital-based quantum functionality and device concepts.

complex materials↗

DOE OSTI2017

Design of a low parasitic inductance SiC power module with double-sided cooling

In this paper, a low-parasitic inductance SiC power module with double-sided cooling is designed and compared with a baseline double-sided cooled module. With the unique 3D layout utilizing vertical interconnection, the power loop inductance is effectively reduced without sacrificing the thermal performance. Both simulations and experiments are carried out to validate the design. Q3D simulation results show a power loop inductance of 1.63 nH, verified by the experiment, indicating more than 60% reduction of power loop inductance compared with the baseline module. With 0Ω external gate resistance turn-off at 600V, the voltage overshoot is less than 9% of the bus voltage at a load of 44.6A.

Yang, Fei↗

DOE OSTI2021

Impact of the Transformer Magnetizing Inductance on the Performance of the Dual-Active Bridge Converter

The magnetizing inductance of the high-frequency transformer in the dual-active bridge (DAB) converter is usually assumed to be much larger than its leakage inductance, thereby the magnetizing current can be negligible. However, ignoring the magnetizing current will lead to an error in the DAB converter design process. This paper analyzes the operation and performance of the DAB converter for a general case in which the transformer magnetizing inductance is taken into consideration. The analysis shows that the magnetizing inductance impacts the soft-switching region, the power transfer capability, and the leakage inductor current. A simulation case study is provided to verify the analysis. A DAB converter prototype is built to experimentally validate the analysis as well.

Yin, Shiyuan↗

DOE OSTI2024

Stacked-Die SiC Half-Bridge Module with Minimum Loop Inductance

Minimizing parasitic inductance of power modules is needed to advance their electrical performance. Innovation in the past decade has driven down the inductance of SiC half-bridge power modules to around 1–2 nH by using multilayer, embedded, and hybrid structures. Further reduction becomes difficult, mainly limited by the excessive interconnects required for the planar placement of vertical conducting chips. To address this, a vertically stacked-die approach is proposed in this paper, taking advantage of the vertical conducting nature of the SiC chips. With ceramic decoupling capacitors integrated, 0.48 nH overall loop inductance is achieved and validated by experimental measurement. This paper also discusses potential approaches to further reduce the inductance.

Ribeiro, Pedro↗

DOE OSTI2018

Design of Low-Inductance Switching Power Cell for GaN HEMT Based Inverter

Here in this paper, an ultra-low inductance power cell is designed for a three-Level Active Neutral Point Clamped (3LANPC) based on 650 V gallium nitride (GaN) HEMT devices. The 3L-ANPC topology with GaN HEMT devices and the selected modulation scheme suitable for wide-bandgap (WBG) devices are presented. The commutation loops, which mainly contribute to voltage overshoots and increase of switching losses, are discussed. The ultra-low inductance power cell design based on a fourlayer Printed Circuit Board (PCB) with the aim to maximize the switching performance of GaN HEMTs is explained. The design of gate drivers for the GaN HEMT devices is presented. Parasitic inductance and resistance of the proposed design are extracted with finite element analysis and discussed. Common mode behaviours based on the SPICE model of the converter are analyzed. Experimental results on the designed 3L-ANPC with the output power of up to 1 kW are presented, which verifies the performance of the proposed design in terms of ultra-low inductance.

42 ENGINEERING↗

DOE OSTI2015

TU-EF-304-10: Efficient Multiscale Simulation of the Proton Relative Biological Effectiveness (RBE) for DNA Double Strand Break (DSB) Induction and Bio-Effective Dose in the FLUKA Monte Carlo Radiation Transport Code

Purpose: One of the more critical initiating events for reproductive cell death is the creation of a DNA double strand break (DSB). In this study, we present a computationally efficient way to determine spatial variations in the relative biological effectiveness (RBE) of proton therapy beams within the FLUKA Monte Carlo (MC) code. Methods: We used the independently tested Monte Carlo Damage Simulation (MCDS) developed by Stewart and colleagues (Radiat. Res. 176, 587–602 2011) to estimate the RBE for DSB induction of monoenergetic protons, tritium, deuterium, hellium-3, hellium-4 ions and delta-electrons. The dose-weighted (RBE) coefficients were incorporated into FLUKA to determine the equivalent {sup 6}°60Co γ-ray dose for representative proton beams incident on cells in an aerobic and anoxic environment. Results: We found that the proton beam RBE for DSB induction at the tip of the Bragg peak, including primary and secondary particles, is close to 1.2. Furthermore, the RBE increases laterally to the beam axis at the area of Bragg peak. At the distal edge, the RBE is in the range from 1.3–1.4 for cells irradiated under aerobic conditions and may be as large as 1.5–1.8 for cells irradiated under anoxic conditions. Across the plateau region, the recorded RBE for DSB induction is 1.02 for aerobic cells and 1.05 for cells irradiated under anoxic conditions. The contribution to total effective dose from secondary heavy ions decreases with depth and is higher at shallow depths (e.g., at the surface of the skin). Conclusion: Multiscale simulation of the RBE for DSB induction provides useful insights into spatial variations in proton RBE within pristine Bragg peaks. This methodology is potentially useful for the biological optimization of proton therapy for the treatment of cancer. The study highlights the need to incorporate spatial variations in proton RBE into proton therapy treatment plans.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2020

Monolithic mtesla-level magnetic induction by self-rolled-up membrane technology

Monolithic strong magnetic induction at the mtesla to tesla level provides essential functionalities to physical, chemical, and medical systems. Current design options are constrained by existing capabilities in three-dimensional (3D) structure construction, current handling, and magnetic material integration. We report here geometric transformation of large-area and relatively thick (~100 to 250 nm) 2D nanomembranes into multiturn 3D air-core microtubes by a vapor-phase self-rolled-up membrane (S-RuM) nanotechnology, combined with postrolling integration of ferrofluid magnetic materials by capillary force. Hundreds of S-RuM power inductors on sapphire are designed and tested, with maximum operating frequency exceeding 500 MHz. An inductance of 1.24 μH at 10 kHz has been achieved for a single microtube inductor, with corresponding areal and volumetric inductance densities of 3 μH/mm 2 and 23 μH/mm 3 , respectively. The simulated intensity of the magnetic induction reaches tens of mtesla in fabricated devices at 10 MHz.

42 ENGINEERING↗

DOE OSTI2020

Developing inductively driven diagnostic X-ray sources to enable transformative radiography and diffraction capabilities on Z

Penetrating X-rays are one of the most effective tools for diagnosing high energy density experiments, whether through radiographic imaging or X-ray diffraction. To expand the X-ray diagnostic capabilities at the 26-MA Z Pulsed Power Facility, we have developed a new diagnostic X-ray source called the inductively driven X-pinch (IDXP). This X-ray source is powered by a miniature transmission line that is inductively coupled to fringe magnetic fields in the final power feed. The transmission line redirects a small amount of Zs magnetic energy into a secondary cavity where 150+ kA of current is delivered to a hybrid X-pinch. In this report, we describe the multi-stage development of the IDXP concept through experiments both on Z and in a surrogate setup on the 1 MA Mykonos facility. Initial short-circuit experiments to verify power ow on Z are followed by short-circuit and X-ray source development experiments on Mykonos. The creation of a radiography-quality X-pinch hot spot is verified through a combination of X-ray diode traces, laser shadowgraphy, and source radiography. The success of the IDXP experiments on Mykonos has resulted in the design and fabrication of an IDXP for an upcoming Z experiment that will be the first-ever X-pinch fielded on Z. We have also pursued the development of two additional technologies. First, the extended convolute post (XCP) has been developed as an alternate method for powering diagnostic X-pinches on Z. This concept, which directly couples the current owing in one of the twelve Z convolute posts to an X-pinch, greatly increases the amount of available current relative to an IDXP (900 kA versus 150 kA). Initial short-circuit XCP experiments have demonstrated the efficacy of power ow in this geometry. The second technology pursued here is the inductively driven transmission line (IDTL) current monitor. These low-current IDTLs seek to measure the current in the final power feed with high fidelity. After three generations of development, IDTL current monitors frequently return cleaner current measurements than the standard B-dot sensors that are fielded on Z. This is especially true on high-inductance experiments where the harshest conditions are created in the nal power feed.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

NASA NTRS1970

Kinetic inductance measured in a superconducting wire

Ultrasensitive technique to measure kinetic inductance has test specimen included as part of the inductance of a tank circuit of a tunnel diode oscillator. Frequency counter measures shift in frequency of oscillator, caused by changes in inductance. Frequency shift in tank circuit is proportional to change in kinetic inductance

Meservey, R. H.↗

NASA NTRS1974

Induction brazing at the Kennedy Space Center

A description of the joint design, materials, equipment, qualification testing, inspection methods, and applications involved in performing induction brazing on hyperbolic propellants tubing at Kennedy Space Center. Induction brazing is a form of brazing in which the energy is transmitted to the workpiece by electrical induction; the eddy currents generated in the metal produce heat by resistance losses. Since induction heating is fast and highly localized, undesirable heat effects are minimized and the resulting braze is of high quality.

Clautice, W. E.↗

NASA NTRS1979

MPD thruster operation with inductively stored energy

Magnetoplasmadynamic (MPD) thrusters with 10-cm and 2.5-cm long thoriated tungsten cathodes have been operated with both inductive and capacitive energy sources at currents up to 8 kA. Voltage-current characteristics and magnetic field measurements show that over most of the operating range, the inductively driven thruster acts as a continuously varying quasi-steady accelerator at the same current. However, at values of a specified parameter near the onset condition for voltage fluctuations and electrode and insulator erosion, the voltage for the inductively driven thruster is higher than its quasi-steady counterpart. This higher voltage occurs because the equilibration time constant of the MPD discharge, is too large to allow the terminal voltage to attain a quasi-steady value as the inductively driven current decreases.

Clark, K. E.↗

NASA NTRS1982

New Energy-Saving Technologies Use Induction Generators

Two energy-saving technologies tested recently at Marshall Space Flight Center use an induction motor operated in reverse (as an induction generator). In the first, energy ordinarily dissipated during load testing of machinery is recovered and returned to powerline. In the second, efficiency of wind-driven induction generator is improved, and useful range of windspeed is broadened. Both technologies take advantage of ac voltage developed across terminals of an induction motor when rotated at higher than-synchronous speed in the direction it normally turns when power is appled.

Nola, F.↗

NASA NTRS1991

Four quadrant control of induction motors

Induction motors are the nation's workhorse, being the motor of choice in most applications due to their simple rugged construction. It has been estimated that 14 to 27 percent of the country's total electricity use could be saved with adjustable speed drives. Until now, induction motors have not been suited well for variable speed or servo-drives, due to the inherent complexity, size, and inefficiency of their variable speed controls. Work at NASA Lewis Research Center on field oriented control of induction motors using pulse population modulation method holds the promise for the desired drive electronics. The system allows for a variable voltage to frequency ratio which enables the user to operate the motor at maximum efficiency, while having independent control of both the speed and torque of an induction motor in all four quadrants of the speed torque map. Multiple horsepower machine drives were demonstrated, and work is on-going to develop a 20 hp average, 40 hp peak class of machine. The pulse population technique, results to date, and projections for implementation of this existing new motor control technology are discussed.

Hansen, Irving G.↗

NASA NTRS1950

Icing-Protection Requirements for Reciprocating-Engine Induction System

Despite the development of relatively ice-free fuel-metering systems, the widespread use of alternate and heated-air intakes, and the use of alcohol for emergency de-icing, icing of aircraft-engine induction systems is a serious problem. Investigations have been made to study and to combat all phases of this icing problem. From these investigations, criterions for safe operation and for design of new induction systems have been established. The results were obtained from laboratory investigations of carburetor-supercharger combinations, wind-tunnel investigations of air scoops, multicylinder-engine studies, and flight investigations. Characteristics of three forms of ice, impact, throttling, and fuel evaporation were studied. The effects of several factors on the icing characteristics were also studied and included: (1) atmospheric conditions, (2) engine and air-scoop configurations, including light-airplane system, (3) type fuel used, and (4) operating variables, such as power condition, use of a manifold pressure regulator, mixture setting, carburetor heat, and water-alcohol injection. In addition, ice-detection methods were investigated and methods of preventing and removing induction-system ice were studied. Recommendations are given for design and operation with regard to induction-system design.

Coles, Willard D↗

NASA NTRS1994

Induction heating coupler

An induction heating device includes a handle having a hollow interior and two opposite ends, a wrist connected to one end of the handle, a U-shaped pole piece having two spaced apart ends, a tank circuit including an induction coil wrapped around the pole piece and a capacitor connected to the induction coil, a head connected to the wrist and including a housing for receiving the U-shaped pole piece, the two spaced apart ends of the pole piece extending outwardely beyond the housing, and a power source connected to the tank circuit. When the tank circuit is energized and a susceptor is placed in juxtaposition to the ends of the U-shaped pole piece, the susceptor is heated by induction heating due to magnetic flux passing between the two ends of the pole piece.

Fox, Robert L.↗

NASA NTRS1994

An investigation of fluid flow during induction stroke of a water analog model of an IC engine using an innovative optical velocimetry concept: LIPA

Optical measurements on an axisymmetrical quartz component engine research model were made to evaluate the flow field encountered during induction. The measurement technique is LIPA (Laser Induced Photochemical Anemometry), a non-intrusive velocimetry concept that provides an investigator of fluid flow with a tool to attain planar information about three-dimensional velocity and vorticity vectors in a single measurement step. The goal of this investigation is to further develop this measurement technique and apply it to study the induction stroke of a water analog model of a four-stroke internal combustion engine. The research conducted in the water analog model is a fundamental scientific inquiry into the flow fields that develop in the induction stroke of an engine at idling engine speeds. As this is the first investigation of its kind using LIPA technique, our goal has been to quantify, in a preliminary manner, the flow field features that develop during the intake stroke. In the process a more comprehensive understanding of the flow field features was developed, and tied to the quantification. The study evaluated the flow field of the intake stroke by estimating fields of velocity and vorticity. On the basis of these data, information about fluid dynamics during induction at engine speeds of 10, 20, and 30 RPM (corresponding to 170, 340, and 510 RPM respectively, when air is the flowing medium) for three different valve lifts was obtained. The overall development of the flow field, its energy content (kinetic, fluctuation) for the different settings of the engine parameters, vorticity information, and cyclic variations have been quantified. These have been discussed in terms of mixing performance.

Stier, Bernd↗