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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 217 records · Page 12

LEED: A Lightwave Energy-Efficient Datacenter

The Lightwave Energy-Efficient Datacenter (LEED) program is a disruptive “green-field” approach that provides a quantum leap in the energy efficiency of datacenters. LEED’s fundamental value proposition is that a novel and re-architected optical network—RotorNet— can deliver “more bandwidth per buck” as well as unique system-level attributes that significantly improve overall datacenter energy efficiency and performance. LEED has developed three system-level testbeds. The first testbed uses calibrated hardware and software power measurements to determine server energy efficiency as a function of network bandwidth and workload. These measurements have shown that increasing network communications bandwidth dramatically increases server energy efficiency providing a realistic path to the overall ENLITENED program goal of doubling the number of transactions per joule. The second testbed demonstrates key hardware: a prototype low-loss, high-port count optical “selector switch”. This switch was fabricated, racked, and tested. Measured switch characteristics include loss, bandwidth, crosstalk, switch time, system-level switch time (including the transceivers), and bit error rate. The third testbed demonstrates a fully working and manufactured pinwheel design which dramatically lowers the cost of design, while delivering high switch radix and low reconfiguration times. The LEED project has tied these three novel photonic switch prototypes together with production servers and software through the development of a novel FPGA-based NIC platform called Corundum. Corundum ensures that the packet-switched protocols supported by commodity operating systems and devices can interface with the Rotor switch design. The LEED group has used this combined hardware and software prototype to characterize applications running at a commercially relevant scale. The project has used a combination of enhanced optical modulation amplitude (OMA) modulators, broadband multiplexers and demultiplexers, avalanche photodiodes, and a novel burst-mode receivers to enable the insertion of LEED-developed optical switches without the need for expensive optical amplification. Our modeling has shown that measured LEED-developed device characteristics can achieve link characteristics of 2 pJ/bit including both transceivers and the Rotor switch. In summary, the LEED program has demonstrated a credible and practical path, through novel hardware and software, to realize the program objectives of ENLITENED. The net result will ensure that the United States maintains its strength in the crucial sector of Information Technology, which is vital to both our economic security and our national security.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Broadband Via-Less Microwave Crossover Using Microstrip-CPW Transitions

The front-to-back interface between microstrip and CPW (coplanar waveguide) typically requires complex fabrication or has high radiation loss. The microwave crossover typically requires a complex fabrication step. The prior art in microstrip-CPW transition requires a physical vias connection between the microstrip and CPW line on a separate layer. The via-less version of this transition was designed empirically and does not have a close form solution. The prior art of the micro wave crossover requires either additional substrate or wire bond as an air bridge to isolate two microwave lines at the crossing junction. The disadvantages are high radiation loss, no analytical solution to the problem, lengthy simulation time, and complex fabrication procedures to generate air bridges or via. The disadvantage of the prior crossover is a complex fabrication procedure, which also affects the device reliability and yield. This microstrip-CPW transition is visualized as two microstrip-slotline transitions combined in a way that the radiation from two slotlines cancels each other out. The invention is designed based on analytical methods; thus, it significantly reduces the development time. The crossover requires no extra layer to cross two microwave signals and has low radiation loss. The invention is simple to fabricate and design. It produces low radiation loss and can be designed with low insertion loss, with some tradeoff with signal isolation. The microstrip-CPW transition is used as an interface to connect between the device and the circuit outside the package. The via-less microwave crossover is used to allow two signals to cross without using an extra layer or fabrication processing step to enable this function. This design allows the solution to be determined entirely though analytical techniques. In addition, a planar via-less microwave crossover using this technique was proposed. The experimental results show that the proposed crossover at 5 GHz has a minimum isolation of 32 dB. It also has low in-band insertion loss and return loss of 1.2 dB and 18 dB, respectively, over more than 44 percent of bandwidth at room temperature. This microstrip-CPW transition requires the microstrip line to be split into two sections. Each section is connected to a microstrip quarter-wavelength openended stub. A slotline is also placed perpendicular to the microstrip section. The slot is connected to a grounded-end quarter-wavelength slotline and generates a microstrip-slotline transition. When two of these sections are placed in parallel and with the microstrip section combined at transition, a microstrip- CPW transition is formed. The slotline radiation is suppressed as two slots are excited with the electric field in an opposite direction, which cancels the radiation in far field. The invention on the crossover consists of the invented microstrip-CPW transitions combined back-to-back and a microstrip low-pass filter. One signal is crossed through to the microstrip layer, while the other signal is crossed through the CPW line located on the ground plane of the microstrip line. The microstrip low-pass filter produces a narrow line at the crossing point to enhance the system isolation. It also produces broadband response in the operating frequency band. The microstrip-CPW transition allows a microwave signal to travel from microstrip line to CPW line with low radiation loss. The crossover allows two microwave signals to cross with minimal parasitic coupling.

Stevenson, Thomas↗

Provision Of Carbon Nanotube Bucky Paper Cages For Immune Shielding Of Cells, Tissues, and Medical Devices

System and method for enclosing cells and/or tissue, for purposes of growth, cell differentiation, suppression of cell differentiation, biological processing and/or transplantation of cells and tissues (biological inserts), and for secretion, sensing and monitoring of selected chemical substances and activation of gene expression of biological inserts implanted into a human body. Selected cells and/or tissue are enveloped in a "cage" that is primarily carbon nanotube Bucky paper, with a selected thickness and porosity. Optionally, selected functional groups, proteins and/or peptides are attached to the carbon nanotube cage, or included within the cage, to enhance the growth and/or differentiation of the cells and/or tissue, to select for certain cellular sub-populations, to optimize certain functions of the cells and/or tissue and/or to optimize the passage of chemicals across the cage surface(s). A cage system is also used as an immuns shield and to control operation of a nano-device or macroscopic device, located within the cage, to provide or transform a selected chemical and/or a selected signal.

Loftus, David J.↗

Error mitigation, optimization, and extrapolation on a trapped-ion testbed

Current noisy intermediate-scale quantum (NISQ) trapped-ion devices are subject to errors which can significantly impact the accuracy of calculations if left unchecked. A form of error mitigation called zero noise extrapolation (ZNE) can decrease an algorithm’s sensitivity to these errors without increasing the number of required qubits. Here we explore different methods for integrating this error mitigation technique into the Variational Quantum Eigensolver (VQE) algorithm for calculating the ground state of the HeH + molecule at 0.8 Å in the presence of experimental noise. Using the Quantum Scientific Computing Open User Testbed (QSCOUT) trapped-ion device, we test three methods of scaling noise for extrapolation: time stretching the two-qubit gates, scaling the sideband detuning parameter, and inserting two-qubit gate identity operations into the ansatz circuit. We find that time stretching and sideband detuning scaling fail to scale the noise on our particular hardware in a way that can be extrapolated to zero noise. Scaling our noise with global gate identity insertions and extrapolating after variational optimization, we achieve error suppression of 96.8%, resulting in an energy estimate within –0.004 ± 0.04 hartree of the ground state energy. This is an improvement, but still outside the chemical accuracy threshold of 0.0016 hartree. Furthermore, our results show that the efficacy of this error mitigation technique depends on choosing the correct implementation for a given device architecture.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Device measures conductivity and velocity of ionized gas streams

Coaxial arrangement of primary coil and two sensing secondary coils contained inside slender quartz tube inserted into ionized stream permits simultaneous determination of conductivity and linear velocity. System results agree favorably with theory.

Cook, G. R.↗

Multiple-Use Mechanisms for Attachment to Seat Tracks

A Seat Track Attach Mechanism (SAM) is a multiple-use clamping device intended for use in mounting various objects on the standard seat tracks used on the International Space Station (ISS). The basic SAM design could also be adapted to other settings in which seat tracks are available: for example, SAM-like devices could be used as universal aircraft-seat-track mounting clamps. A SAM (see figure) is easily installed by inserting it in a seat track, then actuating a locking lever to clamp the SAM to the track. The SAM includes an over-center locking feature that prevents premature disengagement that could be caused by some inadvertent movements of persons or objects in the vicinity. A SAM can be installed in, or removed from, any position along a seat track, without regard for the locations of the circular access holes. Hence, one or more SAM(s) can be used to mount an object or objects on a track or a pair of tracks in an infinite number of preferred configurations. A SAM can be incorporated into a dual swivel device, so that two of the SAMs can be made to lock onto two side-by-side seat tracks simultaneously, as would be the case in a standard ISS rack bay where two side-by-side racks reside. The main benefit to using two SAMs in a side-by-side arrangement is to provide a coupled load. By picking up load points on two seat tracks, a coupled loading is created, improving the stability and strength since the load is spread to two seat tracks at a short distance.

Fraske, Martin↗

High performance tandem organic solar cells via a strongly infrared-absorbing narrow bandgap acceptor

Tandem organic solar cells are based on the device structure monolithically connecting two solar cells to broaden overall absorption spectrum and utilize the photon energy more efficiently. Herein, we demonstrate a simple strategy of inserting a double bond between the central core and end groups of the small molecule acceptor Y6 to extend its conjugation length and absorption range. As a result, a new narrow bandgap acceptor BTPV-4F was synthesized with an optical bandgap of 1.21 eV. The single-junction devices based on BTPV-4F as acceptor achieved a power conversion efficiency of over 13.4% with a high short-circuit current density of 28.9 mA cm -2 . With adopting BTPV-4F as the rear cell acceptor material, the resulting tandem devices reached a high power conversion efficiency of over 16.4% with good photostability. The results indicate that BTPV-4F is an efficient infrared-absorbing narrow bandgap acceptor and has great potential to be applied into tandem organic solar cells.

36 MATERIALS SCIENCE↗

Silicon micromachined waveguides for millimeter and submillimeter wavelengths

The majority of radio receivers, transmitters, and components operating at millimeter and submillimeter wavelengths utilize rectangular waveguides in some form. However, conventional machining techniques for waveguides operating above a few hundred GHz are complicated and costly. This paper reports on the development of silicon micromachining techniques to create silicon-based waveguide circuits which can operate at millimeter and submillimeter wavelengths. As a first step, rectangular WR-10 waveguide structures have been fabricated from (110) silicon wafers using micromachining techniques. The waveguide is split along the broad wall. Each half is formed by first etching a channel completely through a wafer. Potassium hydroxide is used to etch smooth mirror-like vertical walls and LPCVD silicon nitride is used as a masking layer. This wafer is then bonded to another flat wafer using a polyimide bonding technique and diced into the U-shaped half wavelengths. Finally, a gold layer is applied to the waveguide walls. Insertion loss measurements show losses comparable to those of standard metal waveguides. It is suggested that active devices and planar circuits can be integrated with the waveguides, solving the traditional mounting problems. Potential applications in terahertz instrumentation technology are further discussed.

Yap, Markus↗

Ka-Band, MEMS Switched Line Phase Shifters Implemented in Finite Ground Coplanar Waveguide

Ka-band MEMS switched line phase shifters implemented in finite ground coplanar waveguide are described in this paper. The phase shifters are constructed of single-pole double-throw (SPDT) switches with additional reference and phase offset transmission line lengths. The one- and two-bit phase shifters are fabricated on high resistivity (HR) silicon with a dielectric constant, Epsilon(sub T) = 11.7 and a substrate thickness, t = 500microns. The switching architectures integrated within the phase shifters consist of MEMS switches that are doubly anchored cantilever beam capacitive switches with additional high inductive sections (MEMS LC device). The SPDT switch is composed of a T-junction with a MEMS LC device at each output port. The one-bit phase shifter described in this paper has an insertion loss (IL) and return loss (RL) of 0.9 dB and 30 dB while the two-bit described has an IL and RL of 1.8 dB and 30 dB respectively. The one-bit phase shifter's designed offset phase is 22.5deg and actual measured phase shift is 21.8deg. The two-bit phase shifter's designed offset phase is 22.5deg, 45deg, and 67.5deg and the actual measured phase shifts are 21.4deg, 44.2deg, and 65.8deg, respectively.

Scardelletti, Maximilian C.↗

Development of Urine Receptacle Assembly for the Crew Exploration Vehicle

The Urine Receptacle Assembly (URA) initially was developed for Apollo as a primary means of urine collection. The aluminum housing with stainless steel honeycomb insert provided all male crewmembers with a non-invasive means of micturating into a urine capturing device and then venting to space. The performance of the URA was a substantial improvement over previous devices but its performance was not well understood. The Crew Exploration Vehicle (CEV) program is exploring the URA as a contingency liquid waste management system for the vehicle. URA improvements are required to meet CEV requirements, including: consumables minimization, flow performance, acceptable hygiene standards, crew comfort, and female crewmember capability. This paper presents the results of a historical review of URA performance during the Apollo program, recent URA performance tests on the reduced gravity aircraft flight under varying flow conditions, and a proposed development plan for the URA to meet CEV needs.

Cibuzar, Branelle Rae↗

Ultra-compact configurable double-sided manifold micro-channel cold plate

A configurable, double sided, manifold micro-channel cold plate includes a one or more manifold micro-channel cold plate cells. Each cold plate cell includes a manifold body, a manifold insert, a plurality of heat sinks, and a plurality of longitudinal openings configured for fluidic communication with the fluid channels. The manifold body has fluid channels to permit flow of a fluid coolant. The manifold insert has a plurality of manifold insert fluid channels, and is configured for receipt in the one of the modular body recesses. The heat sinks are configured for receipt in the modular body recesses, and include an impingement surface configured for fluidic communication with the manifold insert fluid channels, and a heat transfer surface for thermal communication with one or more heat generating devices.

Zhou, Feng↗

Pressure-Driven Helium Insertion for Structural Stability of CH 3 NH 3 PbBr 3 Hybrid Perovskites

Organic−inorganic metal halide perovskites (MHPs) have garnered significant attention due to their outstanding performance in optoelectronic devices, but they are prone to degradation through a variety of pathways. High-pressure studies are being used to understand the mechanical and structural stability of MHPs and investigate new methods for improving these. In this study, we map the high-pressure, low-temperature structural phase diagram of CH 3 NH 3 PbBr 3 (MAPbBr 3 ) between 15−300 K and up to 1.5 GPa. We first compare the temperature and pressure effects on the global and local structures of MAPbBr 3 using synchrotron X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS), respectively, and find evidence of PbBr 6 octahedral distortion. Our results also suggest that He inserts into the MAPbBr 3 structure. The thermodynamics of He insertion into MAPBHe x are calculated to be plausible at room temperature for x ≤ 1 and P = 1−3 GPa and shown to stabilize higher-symmetry phases. This phenomenon increases the fitted bulk modulus of MAPbBr 3 . Structural stabilization by inert atom insertion is proposed as a method to improve the mechanical robustness of MHPs and other soft hybrid materials.

Diffraction↗

Connector locking device

Slidable spring-loaded locking device eliminates need for safety wiring. Locking device is placed between the connector plug and connector receptacle. The threaded plug cannot vibrate loose because the insert is wedged into slots formed on the outer diameter of the receptacle.

Rabb, L. W.↗

Tool and process for miniature explosive joining of tubes

A tool and process to be used in the explosive joining of tubes is disclosed. The tool consists of an initiator, a tool form, and a ribbon explosive. The assembled tool is a compact, storable, and safe device suitable for explosive joining of small, lightweight tubes down to 0.20 inch in diameter. The invention is inserted into either another tube or a tube plate. A shim or standoff between the two surfaces to be welded is necessary. Initiation of the explosive inside the tube results in a high velocity, angular collision between the mating surfaces. This collision creates surface melts and collision bonding wherein electron-sharing linkups are formed.

Bement, Laurence J.↗

Connector systems for structures

A releasable coupling device for connecting two members to one another where a collet type fastener has normally retracted latching fingers insertable into a latching recess and a longitudinally movable expander for activating the fastener is described. The longitudinal movement is retained with a paraffin actuated system which can reset. The longitudinal movement of the expander in one direction is through a one way threaded ratchet system which provides an automatic locking action and the expander is movable in either direction by an independently operated threaded action.

Lupo, Christian↗

Connector systems for structures

A releasable coupling device for connecting two members to one another where a collet type fastener has normally retracted latching fingers insertable into a latching recess and a longitudinally movable expander for activating the fastener is described. The longitudinal movement is retained with a paraffin actuated system which can reset. The longitudinal movement of the expander in one direction is through a one way threaded ratchet system which provides an automatic locking action and the expander is movable in either direction by an independently operated threaded action.

Evenson, Erik E.↗

Video System For Inspecting Walls Of Cavities

Endoscopic video-imaging system generates panoramic image of part of wall of cavity surrounding tip of probe inserted in cavity. Not necessary to rotate probe to obtain panoramic image. If simple inspection without measurement required, device called "cylindrical light ring" mounted on probe to illuminate scene. Different illumination device used when required to measure distance of wall of cavity from cylindrical axis of probe. System used, for example, to inspect inner surface of tube, passage, or manifold located deep within engine or other complex structure.

Gilbert, John A.↗

Fiber Optic Attenuators

Mike Buzzetti designed a fiber optic attenuator while working at Jet Propulsion Laboratory, intended for use in NASA's Deep Space Network. Buzzetti subsequently patented and received an exclusive license to commercialize the device, and founded Nanometer Technologies to produce it. The attenuator functions without introducing measurable back-reflection or insertion loss, and is relatively insensitive to vibration and changes in temperature. Applications include cable television, telephone networks, other signal distribution networks, and laboratory instrumentation.

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