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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 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Capacitively Coupled LAPPDs with 2D Pixelated Readout Planes for Time of Flight and Ring Imaging Cherenkov Applications

Large Area Picosecond Photon Detectors (LAPPDs) are micro-channel plate based photosensors featuring hundreds of square centimeters of sensitive area in a single package and capable of providing timing resolution on the order of 50 ps for single photon detection. However, LAPPDs currently do not exist in finely pixelated 2D readout configurations which, in addition to ighresolution timing, would also provide high spatial resolution required for Ring Imaging CHerenkov (RICH) detectors. One of the recent LAPPD models (Gen II) provides the opportunity to overcome the lack of pixellation by coupling an external readout to the sealed detector itself. The readout plane in this case is a simple printed circuit board (PCB) that can be laid out in a custom application-specific way for 1D or 2D sensitive area pixellation. This allows for a much shorter readout-plane prototyping cycle and provides unprecedented flexibility in choosing an appropriate segmentation that can be optimized for any particular detector need in terms of pad size, orientation, and shape.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

Self-Sensing, Stretchable, Active Circuit Arrays: Liquid Metal Paste as a Combination Interconnect and Strain Sensor

Stretchable electrical interconnects and substrate materials are increasingly used to create flexible and con-formable electronic systems for soft robotics, smart textiles, and wearable devices. Wires fabricated using composite or liquid conductive inks encapsulated in silicone enable high strain and are mechanically robust. The resistance of these inter-connects increases with strain, which can present challenges for power delivery and signaling among electronic components. However, this effect can be used directly to estimate strain within a stretchable circuit without the need for additional sensor components. In this work, we present an approach for fabricating fully-stretchable, multi-layer active circuit arrays in silicone using liquid metal paste interconnects, in which power and data wires are re-purposed as strain sensors to estimate substrate deformation. As a proof-of-principle, we demonstrate a 3×3 active circuit array that self-senses relative voltage supply at each node to estimate deformation and consumes less than 10 mA per node. Each node is digitally addressable and performs both analog measurement and digital conversion. All interconnects are fabricated using liquid metal paste, and power, data, and sensing are performed over a shared, four-wire interface in this multi-layer stretchable printed circuit board.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2022

System for providing dynamic feedback for selective adhesion PCB production

A system for providing selective adhesion printed circuit board (PCB) production comprises a conveyor mechanism, a curing system, and a computer. The conveyor mechanism is configured to convey a series of selective adhesion blanks, wherein each selective adhesion blank is utilized to produce a PCB and includes a flexible film, a substrate, a conductive layer, and a curable adhesive. The conductive layer is formed from electrically conductive material and adhered to the substrate. The curable adhesive is positioned between the flexible film and the conductive layer and is configured to selectively bond with the conductive layer when the curable adhesive is cured. The curing system is configured to cure the curable adhesive. The computer includes a processing element configured or programmed to: receive a plurality of PCB designs, and direct the curing system to cure the curable adhesive of a plurality of selective adhesion blanks for each PCB design.

Hatch, Jonathan Douglas↗
DOE OSTI2022

Packaging of wide bandgap power electronic power stages

Design and packaging of wide bandgap (WBG) power electronic power stages are disclosed herein. An example apparatus includes a first printed circuit board (PCB) including: a first voltage phase circuit cluster; a second voltage phase circuit cluster; and a cluster of traces, the cluster of traces routed substantially perpendicular to the second voltage phase circuit cluster; a second PCB positioned below the first PCB; and a connector to connect the first PCB to the second PCB, the connector electrically coupled to the first voltage phase circuit cluster by the cluster of traces.

Singh, Brij N.↗
DOE OSTI2023

Antenna assemblies and antenna systems

Antenna assemblies and antenna systems are described. According to one aspect, a printed circuit board antenna system includes a dielectric substrate comprising first and second surfaces that are opposite to one another, first electrically conductive material of an antenna element adjacent to the first surface of the dielectric substrate, wherein the antenna element is configured to emit electromagnetic energy, and second electrically conductive material of a ground plane adjacent to the second surface of the dielectric substrate, wherein the ground plane is aligned with the antenna element and configured to reflect some of the electromagnetic energy in a direction towards the antenna element.

Grando, Maurio B.↗
DOE OSTI2024

Recovery of valuable metals from electronic waste using a novel ammonia-based hydrometallurgical process

The growing quantity of waste electrical and electronic equipment (WEEE), also known as electronic waste (E-waste), has been an area of growing public concern. The abundance of valuable metals contained in waste printed circuit boards (WPCBs) has made it a promising secondary resource, especially for Cu and Au. Although the recovery of metals from WPCBs via hydrometallurgical routes has been studied extensively over the past 20 years, most of the research has been limited in the laboratory. In current hydrometallurgical processes, strong acids and expensive oxidizers are often used to ensure a high recovery of metals without considering the sustainability aspects of the environment and economics. To improve upon current hydrometallurgical offerings, the current study seeks to develop an energy-saving, environmentally friendly, economic and sustainable process to efficiently recover the valuable metals from real-world end-of-life WPCBs. The new contributions presented in this study are 1) design and evaluation of a comprehensive hydrometallurgical flowsheet; 2) employment of real end-of-life PCBs as feed materials in an investigation on Cu-NH3 leaching kinetics; 3) further application of kinetic model on a counter flow process simulation; and 4) evaluation of the influences by co-existing metals in Au-S2O3 leaching and recommendation for favorable leaching conditions.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2025

Packaging a 650V/400A GaN Half-bridge Power Module with Ultra-low Parasitics for Electric Vehicle Drive Applications

This paper proposes a compact and efficient half-bridge power module with three 650 V / 150 A GaN dies in parallel. The power module incorporates a main power printed circuit board (PCB), an interface PCB, and a flex PCB to achieve low parasitics in both power loop and gate-side connection, resolving the issue of high parasitics typically encountered with wire bonding in high-current applications. Additionally, the interface PCB decouples the design constraints between the power loop and the gate loops. The proposed design is optimized with a vertical loop configuration to reduce power loop inductance through magnetic flux cancellation. Finite element analysis indicates that the power loop inductance is 0.58 nH at 100 MHz, while the maximum die junction temperature reaches 131 °C under an ambient temperature of 65 °C and a load current of 385 A. The proposed multi-piece PCB structure reduces the inductance of the drive circuit to minimize EMI and to mitigate false triggering. At the same time, it reduces impedance mismatches across different driver circuits, thereby achieving dynamic current sharing in multi-chip parallel configurations. Under simulation conditions of 400 V / 385 A, the current imbalance among chips was limited to 5 A. A 400 V / 385 A double-pulse test was conducted to experimentally validate the performance of the proposed power module.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2026

Space Cooling: Recovery, Reuse, Recycling and Supply Chain Impacts

The global cooling sector has undergone tremendous growth in recent years, and cooling demand is projected to double or triple by 2050. Surging air conditioning demand will continue to be driven by increased populations, incomes and occurrences of extreme heat and humidity events. Cooling equipment growth has important pollution and material implications as they are made up of critical metals and precious raw materials - including ferrous metals, copper, aluminum and printed circuit boards composed of copper, silver, gold and palladium - that generate significant electronic waste at end-of-life. Air conditioning equipment also contains fluorinated gas (F-gas) refrigerants, which are potent gases that are thousands of times more heat-trapping than carbon dioxide (CO2). While recovery, reuse, and recycling strategies have been assessed for cold chain and refrigeration, there is currently limited analysis on how these strategies could be adopted for the global space cooling industry and potential supply chain implications. This paper aims to address this research gap by qualitatively evaluating product and material recovery, reuse and recycling frameworks from both demand and supply-side perspectives and with the support of cooling-specific case studies. It also focuses on quantitatively assessing potential energy, emissions and resource benefits of such strategies for space cooling equipment. This paper first analyzes how existing recovery, reuse and recycling frameworks can be applied to space cooling, with emphasis on the demand-side enablers (e.g., innovative business models, supporting policies and regulations) and changes in supply-side production network throughout the supply chain (e.g., design, production and distribution, end-of-life recovery) needed to overcome existing barriers. It will present case studies of innovative business models for space cooling technologies, including reuse and recycling, and how effective refrigerant reclamation and recovery programs have been operationalized. Lastly, the paper will highlight global modeling results of energy, emissions and material recovery from scenario analysis of selected strategies for air conditioners. The findings of this paper are intended to inform the development of product and material recovery, reuse and recycling strategies for a rapidly growing stock of space conditioning equipment by addressing existing organizational, economic and regulatory barriers and potential supply-chain bottlenecks.

Khanna, Nina↗
NASA NTRS2007

Arrays of Miniature Microphones for Aeroacoustic Testing

A phased-array system comprised of custom-made and commercially available microelectromechanical system (MEMS) silicon microphones and custom ancillary hardware has been developed for use in aeroacoustic testing in hard-walled and acoustically treated wind tunnels. Recent advances in the areas of multi-channel signal processing and beam forming have driven the construction of phased arrays containing ever-greater numbers of microphones. Traditional obstacles to this trend have been posed by (1) the high costs of conventional condenser microphones, associated cabling, and support electronics and (2) the difficulty of mounting conventional microphones in the precise locations required for high-density arrays. The present development overcomes these obstacles. One of the hallmarks of the new system is a series of fabricated platforms on which multiple microphones can be mounted. These mounting platforms, consisting of flexible polyimide circuit-board material (see left side of figure), include all the necessary microphone power and signal interconnects. A single bus line connects all microphones to a common power supply, while the signal lines terminate in one or more data buses on the sides of the circuit board. To minimize cross talk between array channels, ground lines are interposed as shields between all the data bus signal lines. The MEMS microphones are electrically connected to the boards via solder pads that are built into the printed wiring. These flexible circuit boards share many characteristics with their traditional rigid counterparts, but can be manufactured much thinner, as small as 0.1 millimeter, and much lighter with boards weighing as much as 75 percent less than traditional rigid ones. For a typical hard-walled wind-tunnel installation, the flexible printed-circuit board is bonded to the tunnel wall and covered with a face sheet that contains precise cutouts for the microphones. Once the face sheet is mounted, a smooth surface is established over the entire array due to the flush mounting of all microphones (see right side of figure). The face sheet is made from a continuous glass-woven-fabric base impregnated with an epoxy resin binder. This material offers a combination of high mechanical strength and low dielectric loss, making it suitable for withstanding the harsh test section environment present in many wind tunnels, while at the same time protecting the underlying polyimide board. Customized signal-conditioning hardware consisting of line drivers and antialiasing filters are coupled with the array. The line drivers are constructed using low-supply-current, high-gain-bandwidth operational amplifiers designed to transmit the microphone signals several dozen feet from the array to external acquisition hardware. The anti-alias filters consist of individual Chebyshev low-pass filters (one for each microphone channel) housed on small printed-circuit boards mounted on one or more motherboards. The mother/daughter board design results in a modular system, which is easy to debug and service and which enables the filter characteristics to be changed by swapping daughter boards with ones containing different filter parameters. The filter outputs are passed to commercially- available acquisition hardware to digitize and store the conditioned microphone signals. Wind-tunnel testing of the new MEMS microphone polyimide mounting system shows that the array performance is comparable to that of traditional arrays, but with significantly less cost of construction.

Shams, Qamar A.↗
NASA NTRSDate not supplied

PCB Quality Metrics that Drive Reliability

Risk-based technology infusion is a deliberate and systematic process that defines the analysis and communication methodology by which new technology is applied and integrated into existing and new designs, identifies technology development needs based on trends analysis and facilitates the identification of shortfalls against performance objectives. This presentation at IPC Works Asia Aerospace 2021 Events provides the audience a snapshot of quality variations in printed-wiring-board quality, as assessed, using experiences in processing and risk analysis of PWB structural integrity coupons. The presentation will focus on printed-wiring-board quality metrics used, the relative type and number of non-conformances observed and trend analysis using statistical methods. Trend analysis shows the top five non-conformances observed across PWB suppliers, the root cause(s) behind these non-conformance and suggestions of mitigation plans. The trends are then matched with the current state of the PWB supplier base and its challenges and opportunities. The presentation further discusses the risk-based SMA approaches and methods being applied at GSFC for evaluating candidate printed wiring board technologies that promote the adoption of higher throughput and faster processing technology for GSFC missions.

Printed circuit boards↗
NASA NTRS2018

Printed Wiring Board Technology Infusion and Supplier Capability Overview

Risk based technology infusion is a deliberate and systematic process which defines the analysis and communication methodology by which new technology is applied and integrated into existing and new designs, identifies technology development needs based on trends analysis and facilitates the identification of shortfalls against performance objectives. This presentation at QLF 2018 provides the audience a snapshot of quality variations in printed wiring board quality, as assessed, using experiences in processing and risk analysis of PWB structural integrity coupons. The presentation will focus on printed wiring board quality metrics used, the relative type and number of non-conformances observed and trend analysis using statistical methods. Trend analysis shows the top five non-conformances observed across PWB suppliers, the root cause(s) behind these non-conformance and suggestions of mitigation plans. The trends will then be matched with the current state of the PWB supplier base and its challenges and opportunities. The presentation further discusses the methods being applied at GSFC for evaluating candidate printed wiring board technologies which promote the adoption of higher throughput and faster processing technology for GSFC missions.

PCB fabrication↗
DOE OSTI2022

The ultrafast pixel array camera system and its applications in high energy density physics

Diagnostics in high energy density physics, shock physics, and related fields are primarily driven by a need to record rapidly time-evolving signals in single-shot events. These measurements are often limited by channel count and signal degradation issues on cable links between the detector and digitizer. Here we present the Ultrafast Pixel Array Camera (UPAC), a compact and flexible detector readout system with 32 waveform-recording channels at up to 10 Gsample/s and 1.8 GHz analog bandwidth. The compact footprint allows the UPAC to be directly embedded in the detector environment. A key enabling technology is the PSEC4A chip, an eight-channel switch-capacitor array sampling device with up to 1056 samples/channel. The UPAC system includes a high-density input connector that can plug directly into an application-specific detector board, programmable control, and serial readout, with less than 5 W of power consumption in full operation. We present the UPAC design and characterization, including a measured timing resolution of ~20 ps or better on acquisitions of sub-nanosecond pulses with minimal system calibrations. Example applications of the UPAC are also shown to demonstrate operation of a solid-state streak camera, an ultrafast imaging array, and a neutron time-of-flight spectrometer.

47 OTHER INSTRUMENTATION↗
DOE OSTI2022

Beam particle identification and tagging of incompletely stripped heavy beams with HEIST

A challenge preventing successful inverse kinematics measurements with heavy nuclei that are not fully stripped is identifying and tagging the beam particles. For this purpose, the HEavy ISotope Tagger (HEIST) has been developed. HEIST utilizes two micro-channel plate timing detectors to measure the time-of-flight, a multi-sampling ion chamber to measure energy loss, and a high-purity germanium detector to identify isomer decays and calibrate the isotope identification system. HEIST has successfully identified 198 Pb and other nearby nuclei at energies of about 75 MeV/A. In the experiment discussed, a typical cut containing 89% of all 198 Pb 80+ in the beam had a purity of 86%. We examine the issues of charge state contamination. Here, the observed charge state populations of these ions are presented and, using an adjusted beam energy, are well described by the charge state model GLOBAL.

47 OTHER INSTRUMENTATION↗
DOE OSTI2023

Radio frequency electrical resistance measurement under destructive pulsed magnetic fields

We developed a resistance measurement using radio frequency reflection to investigate the electrical transport characteristics under destructive pulsed magnetic fields above 100 T. A sample stage consisting of a homemade flexible printed circuit reduced the noise caused by the induced voltage from the pulsed magnetic fields, improving the accuracy of the measurements of the reflected waves. From the obtained reflectance data, the absolute value of the magnetoresistance was successfully determined by analyzing the phase with admittance charts. In conclusion, these developments enable more accurate and comprehensive measurements of electrical resistance in pulsed magnetic fields.

47 OTHER INSTRUMENTATION↗
DOE OSTI2024

Magnetometry in a diamond anvil cell using nitrogen vacancy centers in a nanodiamond ensemble

The emerging field of optical magnetometry utilizing negative-charged nitrogen vacancy (NV – ) centers provides a highly sensitive lab bench technique for spatially resolved physical property measurements. Their implementation in high pressure diamond anvil cell (DAC) environments will become common as other techniques are often limited due to the spatial constraints of the sample chamber. Apparatus and techniques are described here permitting for more general use of magnetic field measurements inside a DAC using continuous wave optical detected magnetic resonance in NV – centers in a layer of nanodiamonds. A microstrip antenna delivers a uniform microwave field to the DAC and is compatible with simple metal gaskets, and the sensor layer of deposited nanodiamonds allows for simple determination of the magnetic field magnitude for B in the 1–100 G range. The ferromagnetic transition in iron at 18 GPa is measured with the apparatus, along with its hysteretic response.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Estimation, Minimization, and Validation of Commutation Loop Inductance for a 135-kW SiC EV Traction Inverter

With growing interests in low inductance SiC based power module packaging, it is vital to focus on system level design aspects to facilitate easy integration of the modules and reap system level benefits. To effectively utilize the low inductance modules, busbar and interconnects should also be designed with low stray inductances. A wholistic investigation of the flux path and flux cancellations in the module-busbar assembly which as differentially coupled series inductors is thus mandatory for a system level design. This work presents a busbar design which can be adopted to effectively integrate the CREE’s low inductance 1.2 kV/1.7 kV SiC power modules. The paper also proposes a novel measurement technique to measure the inductance of the modulebusbar assembly as a whole rather than deducing it from individual components. The inductance of the overall commutation loop of the inverter which encompasses the SiC power module, interconnects and PCB busbar have been estimated using finite element analysis (FEA). Furthermore, insights gained from FEA provided the guidelines to decide on the placement of the decoupling capacitors in the busbar to minimize the overall commutation loop inductance from 12.8 nH to 7.4 nH which resulted in significant reduction in the device voltage overshoot. The simulation results have been validated through measurements using an impedance analyzer with less than 5% difference between extracted loop inductance from FEA and measurements. The bus bar design study and the measurement technique discussed in this paper, can be easily extended to other power module packages. Finally, the 135 kW inverter has been compared to a similar highpower inverter utilizing a laminated busbar to highlight the performance of the former.

42 ENGINEERING↗
DOE OSTI2024

High-Temperature Wireless Sensor Platform Powered by Energy Scavenging

This paper reports on the development of key components required for a self-powered oscillator unit designed to wirelessly transmit its signal under full insertion in high-temperature (HT) harsh-environments (HE), such as those present in power plants and industrial settings (metallurgic, oil extraction, molding, and aerospace). The oscillator employed a silicon carbide (SiC) power transistor and HT passive components on a screen-printed alumina circuit board capable of operation beyond 300 °C. The HT oscillator circuit was powered solely by in-situ energy scavenging thermoelectric generator (TEG) modules using passive cooling, eliminating the need for an external power supply or active cooling. In addition, a silicon-based external booster circuit was used to achieve the required TEG voltage regulation to test the TEG-powered HT oscillator circuit. The TEG-powered oscillator circuit was tested inside a non-metallic furnace from room temperature to over 300 °C for transmission of a wireless signal, which was detected outside the furnace at 11 ft (3.4 m). Such a wireless transmitting system powered only by in-situ TEGs, with no requirement for external power or active cooling, is very attractive for flexible, mobile stand-alone control and sensor units targeted for operation in HT HE conditions found in power plants and industrial settings.

20 FOSSIL-FUELED POWER PLANTS↗