Electrostatic Evaluation of the SRB Velostat(Trademark) Pads

NASA Technical Reports Server (NTRS)

Buhler, Charles R.; Calle, Carlos I.

2007-01-01

During RSRM Grain inspection, pads constructed of Velostat are grounded and installed in the RSRM bore enabling inspectors to move throughout the bore during the inspection. Velostat pads are installed by grounding the first pad installed and subsequent pads are installed overlapping the previously installed pad maintaining a conductive path to facility ground. Pads are removed upon completion of the inspection in a reverse fashion. As the pads are removed scanning of propellant surfaces is performed per OMRS. During PPICI Audit of B5308.006 (Forward Segment Grain Inspection) in October 07 one audit finding noted that electrostatic scanning of propellant surfaces was being performed during removal of conductive pads following grain inspection. ATK does not perform electrostatic scanning of propellant surfaces during pad removal following final inspection at the plant. The integrated team consisting of NASA SE, USA SE, USA QE, ATK LSS, ATK Systems Safety and ATK DE concurred that electrostatic scanning of propellant surfaces was unnecessary as the conductive pads are grounded. Additional time spent in bore performing scanning presents itself as additional risk. Technicians reported that they have never seen any voltage readings while scanning propellant surfaces during pad removal. USA Systems engineering has written KB 17530 in response to the finding which will delete the requirement (item 2 B47GEN.ll0) to scan propellant surfaces during pad removal. As a result of an E3 panel discussion on December 13, 2007, it was decided that verification of the electrical grounding of the Velostat pads be verified.

Voyager spacecraft electrostatic discharge testing

NASA Technical Reports Server (NTRS)

Whittlesey, A.; Inouye, G.

1980-01-01

The program of environmental testing undergone by the Voyager spacecraft in order to simulate the transient voltage effects of electrostatic discharges expected in the energetic plasma environment of Jupiter is reported. The testing consists of studies of the electrostatic discharge characteristics of spacecraft dielectrics in a vacuum-chamber-electron beam facility, brief piece part sensitivity tests on such items as a MOSFET multiplexer and the grounding of the thermal blanket, and assembly tests of the magnetometer boom and the science boom. In addition, testing of a complete spacecraft was performed using two arc sources to simulate long and short duration discharge sources for successive spacecraft shielding and grounding improvements. Due to the testing program, both Voyager 1 and Voyager 2 experienced tolerable electrostatic discharge-caused transient anomalies in science and engineering subsystems, however, a closer duplication of the spacecraft environment is necessary to predict and design actual spacecraft responses more accurately.

Characterizing the Performance of the Wheel Electrostatic Spectrometer

NASA Technical Reports Server (NTRS)

Johansen, Michael R.; Mackey, P. J.; Holbert, E.; Calle, C. I.; Clements, J. S.

2013-01-01

Insulators need to be discharged after each wheel revolution. Sensor responses repeatable within one standard deviation in the noise of the signal. Insulators may not need to be cleaned after each revolution. Parent Technology- Mars Environmental Compatibility Assessment/Electrometer Electrostatic sensors with dissimilar cover insulators Protruding insulators tribocharge against regolith simulant Developed for use on the scoop for the 2001 Mars Odyssey lander Wheel Electrostatic Spectrometer Embedded electrostatic sensors in prototype Martian rover wheel If successful, this technology will enable constant electrostatic testing on Mars Air ionizing fan used to neutralize the surface charge on cover insulators . WES rolled on JSClA lunar simulant Control experiment -Static elimination not conducted between trials -Capacitor discharged after each experiment Charge neutralization experiment -Static elimination conducted between trials -Capacitor discharged after each experiment. Air ionizing fan used on insulators after each wheel revolution Capacitor discharged after each trial Care was taken to roll WES with same speed/pressure Error bars represent one standard deviation in the noise of e ach sensor

Channel Modeling of Miniaturized Battery-Powered Capacitive Human Body Communication Systems.

PubMed

Park, Jiwoong; Garudadri, Harinath; Mercier, Patrick P

2017-02-01

The purpose of this contribution is to estimate the path loss of capacitive human body communication (HBC) systems under practical conditions. Most prior work utilizes large grounded instruments to perform path loss measurements, resulting in overly optimistic path loss estimates for wearable HBC devices. In this paper, small battery-powered transmitter and receiver devices are implemented to measure path loss under realistic assumptions. A hybrid electrostatic finite element method simulation model is presented that validates measurements and enables rapid and accurate characterization of future capacitive HBC systems. Measurements from form-factor-accurate prototypes reveal path loss results between 31.7 and 42.2 dB from 20 to 150 MHz. Simulation results matched measurements within 2.5 dB. Comeasurements using large grounded benchtop vector network analyzer (VNA) and large battery-powered spectrum analyzer (SA) underestimate path loss by up to 33.6 and 8.2 dB, respectively. Measurements utilizing a VNA with baluns, or large battery-powered SAs with baluns still underestimate path loss by up to 24.3 and 6.7 dB, respectively. Measurements of path loss in capacitive HBC systems strongly depend on instrumentation configurations. It is thus imperative to simulate or measure path loss in capacitive HBC systems utilizing realistic geometries and grounding configurations. HBC has a great potential for many emerging wearable devices and applications; accurate path loss estimation will improve system-level design leading to viable products.

On the influence that the ground electrode diameter has in the propulsion efficiency of an asymmetric capacitor in nitrogen gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martins, Alexandre A.; Pinheiro, Mario J.

In this work, the propulsion force developed in an asymmetric capacitor will be calculated for three different diameters of the ground electrode. The used ion source is a small diameter wire, which generates a positive corona discharge in nitrogen gas directed to the ground electrode. By applying the fluid dynamic and electrostatic theories, all hydrodynamic and electrostatic forces that act on the considered geometries will be computed in an attempt to provide a physical insight on the force mechanism that acts on the asymmetrical capacitors, and also to understand how to increase the efficiency of propulsion.

Hydraulically amplified self-healing electrostatic actuators with muscle-like performance

NASA Astrophysics Data System (ADS)

Acome, E.; Mitchell, S. K.; Morrissey, T. G.; Emmett, M. B.; Benjamin, C.; King, M.; Radakovitz, M.; Keplinger, C.

2018-01-01

Existing soft actuators have persistent challenges that restrain the potential of soft robotics, highlighting a need for soft transducers that are powerful, high-speed, efficient, and robust. We describe a class of soft actuators, termed hydraulically amplified self-healing electrostatic (HASEL) actuators, which harness a mechanism that couples electrostatic and hydraulic forces to achieve a variety of actuation modes. We introduce prototypical designs of HASEL actuators and demonstrate their robust, muscle-like performance as well as their ability to repeatedly self-heal after dielectric breakdown—all using widely available materials and common fabrication techniques. A soft gripper handling delicate objects and a self-sensing artificial muscle powering a robotic arm illustrate the wide potential of HASEL actuators for next-generation soft robotic devices.

Lab-on-a-Chip Sensor for Monitoring Perchlorate in Ground and Surface Water

DTIC Science & Technology

2012-02-01

uses zwitterionic surfactants was immobilized on either a conventional or membrane-based stationary phase (electrostatic ion chromatography ) em...substantially higher than that of drinking water. A novel extraction method incorporat- ing the fundamentals of electrostatic ion chromatography (EIC) was...electrostatic ion chromatography (EIC), is presented as a way to overcome this challenge. Two extraction formats, employing either a packed bed or a monolith

Thermal energy harvesters with piezoelectric or electrostatic transducer

NASA Astrophysics Data System (ADS)

Prokaryn, Piotr; Domański, Krzysztof; Marchewka, Michał; Tomaszewski, Daniel; Grabiec, Piotr; Puscasu, Onoriu; Monfray, Stéphane; Skotnicki, Thomas

2014-08-01

This paper describes the idea of the energy harvester which converts thermal gradient present in environment into electricity. Two kinds of such devices are proposed and their prototypes are shown and discussed. The main parts of harvesters are bimetallic spring, piezoelectric transducer or electrostatic transducer with electret. The applied piezomembrane was commercial available product but electrets was made by authors. In the paper a fabrication procedure of electrets formed by the corona discharge process is described. Devices were compared in terms of generated power, charging current, and the voltage across a storage capacitor.

Anomalous Ground State of the Electrons in Nano-confined Water

DTIC Science & Technology

2016-06-13

confined water system, Nafion, is so different from that of bulk water that the weakly electrostatically interacting molecule model of water is clearly...assume that water is made up molecules weakly interacting(on the scale of the zero point bond energy~.2eV) electrostatically with its neighbors2-3. In an...not possible for a collection of molecules interacting weakly electrostatically . These changes in the spatial distribution of valence electrons in

Microgravity

NASA Image and Video Library

1998-09-30

The Electrostatic Levitator (ESL) Facility established at Marshall Space Flight Center (MSFC) supports NASA's Microgravity Materials Science Research Program. NASA materials science investigations include ground-based, flight definition and flight projects. Flight definition projects, with demanding science concept review schedules, receive highest priority for scheduling experiment time in the Electrostatic Levitator (ESL) Facility.

A Large Aperture Fabry-Perot Tunable Filter Based On Micro Opto Electromechanical Systems Technology

NASA Technical Reports Server (NTRS)

Greenhouse, Matt; Mott, Brent; Powell, Dan; Barclay, Rich; Hsieh, Wen-Ting

2002-01-01

A research and development effort sponsored by the NASA Goddard Spaceflight Center (GSFC) is focused on applying Micro Opto Electromechanical Systems (MOEMS) technology to create a miniature Fabry-Perot tunable etalon for space and ground-based near infrared imaging spectrometer applications. Unlike previous devices developed for small-aperture telecommunications systems, the GSFC research is directed toward a novel 12 - 40 mm aperture for astrophysical studies, including emission line imaging of galaxies and nebulae, and multi-spectral redshift surveys in the 1.1 - 2.3 micron wavelength region. The MOEMS design features integrated electrostatic scanning of the 11-micron optical gap, and capacitance micrometry for closed loop control of parallelism within a 10-nm tolerance. The low thermal mass and inertia inherent in MOEMS devices allows for rapid cooling to the proposed 30 K operating temperature, and high frequency response. Achieving the proposed 6-nm aperture flatness (with an effective finesse of 50) represents the primary technical challenge in the current 12-mm prototype.

Lightning and surge protection, grounding, bonding and shielding requirements for facilities and electronic equipment

DOT National Transportation Integrated Search

2002-08-09

This document mandates standard lightning protection, transient protection, electrostatic discharge (ESD), grounding, bonding and shielding configurations and procedures for new facilities, facility modifications, facility up grades, new equipment in...

An electrostatic autoresonant ion trap mass spectrometer.

PubMed

Ermakov, A V; Hinch, B J

2010-01-01

A new method for ion extraction from an anharmonic electrostatic trap is introduced. Anharmonicity is a common feature of electrostatic traps which can be used for small scale spatial confinement of ions, and this feature is also necessary for autoresonant ion extraction. With the aid of ion trajectory simulations, novel autoresonant trap mass spectrometers (ART-MSs) have been designed based on these very simple principles. A mass resolution approximately 60 is demonstrated for the prototypes discussed here. We report also on the pressure dependencies, and the (mV) rf field strength dependencies of the ART-MS sensitivity. Importantly the new MS designs do not require heavy magnets, tight manufacturing tolerances, introduction of buffer gases, high power rf sources, nor complicated electronics. The designs described here are very inexpensive to implement relative to other instruments, and can be easily miniaturized. Possible applications are discussed.

Characterizing the Perfonnance of the Wheel Electrostatic Spectrometer

NASA Technical Reports Server (NTRS)

Johansen, Michael R.; Mackey, P. J.; Holbert, E.; Clements, J. S.; Calle, C. I.

2013-01-01

A Wheel Electrostatic Spectrometer has been developed as a surveying tool to be incorporated into a planetary rover design. Electrostatic sensors with various protruding cover insulators are embedded into a prototype rover wheel. When these insulators come into contact with a surface, a charge develops on the cover insulator through tribocharging. A charge spectrum is created by analyzing the accumulated charge on each of the dissimilar cover insulators. We eventually intend to prove charge spectra can be used o determine differences in planetary regolith properties. We tested the effects of residual surface charge on the cover insulators and discovered a need to discharge the sensor cover insulators after each revolution. We proved the repeatability of the measurements for this sensor package and found that the sensor repeatability lies within one standard deviation of the noise in the signal.

Ground Based Investigation of Electrostatic Accelerometer in HUST

NASA Astrophysics Data System (ADS)

Bai, Y.; Zhou, Z.

2013-12-01

High-precision electrostatic accelerometers with six degrees of freedom (DOF) acceleration measurement were successfully used in CHAMP, GRACE and GOCE missions which to measure the Earth's gravity field. In our group, space inertial sensor based on the capacitance transducer and electrostatic control technique has been investigated for test of equivalence principle (TEPO), searching non-Newtonian force in micrometer range, and satellite Earth's field recovery. The significant techniques of capacitive position sensor with the noise level at 2×10-7pF/Hz1/2 and the μV/Hz1/2 level electrostatic actuator are carried out and all the six servo loop controls by using a discrete PID algorithm are realized in a FPGA device. For testing on ground, in order to compensate one g earth's gravity, the fiber torsion pendulum facility is adopt to measure the parameters of the electrostatic controlled inertial sensor such as the resolution, and the electrostatic stiffness, the cross couple between different DOFs. A short distance and a simple double capsule equipment the valid duration about 0.5 second is set up in our lab for the free fall tests of the engineering model which can directly verify the function of six DOF control. Meanwhile, high voltage suspension method is also realized and preliminary results show that the horizontal axis of acceleration noise is about 10-8m/s2/Hz1/2 level which limited mainly by the seismic noise. Reference: [1] Fen Gao, Ze-Bing Zhou, Jun Luo, Feasibility for Testing the Equivalence Principle with Optical Readout in Space, Chin. Phys. Lett. 28(8) (2011) 080401. [2] Z. Zhu, Z. B. Zhou, L. Cai, Y. Z. Bai, J. Luo, Electrostatic gravity gradiometer design for the advanced GOCE mission, Adv. Sp. Res. 51 (2013) 2269-2276. [3] Z B Zhou, L Liu, H B Tu, Y Z Bai, J Luo, Seismic noise limit for ground-based performance measurements of an inertial sensor using a torsion balance, Class. Quantum Grav. 27 (2010) 175012. [4] H B Tu, Y Z Bai, Z B Zhou, L Liu, L Cai, and J Luo, Performance measurements of an inertial sensor with a two-stage controlled torsion pendulum, Class Quantum. Grav. 27 (2010) 205016.

ELECTROSTATIC SURFACE STRUCTURES OF COAL AND MINERAL PARTICLES

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

It is the purpose of this research to study electrostatic charging mechanisms related to electrostatic beneficiation of coal with the goal of improving models of separation and the design of electrostatic separators. Areas addressed in this technical progress report are (a) electrostatic beneficiation of Pittsburgh #8 coal powders as a function of grind size and processing atmosphere; (b) the use of fluorescent micro-spheres to probe the charge distribution on the surfaces of coal particles; (c) the use of electrostatic beneficiation to recover unburned carbon from flyash; (d) the development of research instruments for investigation of charging properties of coal. Pittsburghmore » #8 powders were beneficiated as a function of grind size and under three atmosphere conditions: fresh ground in air , after 24 hours of air exposure, or under N2 atmosphere. The feed and processed powders were analyzed by a variety of methods including moisture, ash, total sulfur, and pyritic sulfur content. Mass distribution and cumulative charge of the processed powders were also measured. Fresh ground coal performed the best in electrostatic beneficiation. Results are compared with those of similar studies conducted on Pittsburgh #8 powders last year (April 1, 1997 to September 30, 1997). Polystyrene latex spheres were charged and deposited onto coal particles that had been passed through the electrostatic separator and collected onto insulating filters. The observations suggest bipolar charging of individual particles and patches of charge on the particles which may be associated with particular maceral types or with mineral inclusions. A preliminary investigation was performed on eletrostatic separation of unburned carbon particles from flyash. Approximately 25% of the flyash acquired positive charge in the copper tribocharger. This compares with 75% of fresh ground coal. The negatively charged material had a slightly reduced ash content suggesting some enrichment of carbonaceous material. There was also evidence that the carbon is present at a higher ratio in larger particles than in small particles. An ultraviolet photoelectron counter for use in ambient atmosphere is nearing completion. The counter will be used to measure work functions of different maceral and mineral types in the coal matrix. A Particle Image Analyzer for measuring size and charge of airborne particles is also under contruction and its current status is presented. A charged, monodisperse, droplet generator is also being constructed for calibration of the Particle Image Analyzer and other airborne particle analyzers in our labs.« less

Research and Development of Electrostatic Accelerometers for Space Science Missions at HUST.

PubMed

Bai, Yanzheng; Li, Zhuxi; Hu, Ming; Liu, Li; Qu, Shaobo; Tan, Dingyin; Tu, Haibo; Wu, Shuchao; Yin, Hang; Li, Hongyin; Zhou, Zebing

2017-08-23

High-precision electrostatic accelerometers have achieved remarkable success in satellite Earth gravity field recovery missions. Ultralow-noise inertial sensors play important roles in space gravitational wave detection missions such as the Laser Interferometer Space Antenna (LISA) mission, and key technologies have been verified in the LISA Pathfinder mission. Meanwhile, at Huazhong University of Science and Technology (HUST, China), a space accelerometer and inertial sensor based on capacitive sensors and the electrostatic control technique have also been studied and developed independently for more than 16 years. In this paper, we review the operational principle, application, and requirements of the electrostatic accelerometer and inertial sensor in different space missions. The development and progress of a space electrostatic accelerometer at HUST, including ground investigation and space verification are presented.

Research and Development of Electrostatic Accelerometers for Space Science Missions at HUST

PubMed Central

Bai, Yanzheng; Li, Zhuxi; Hu, Ming; Liu, Li; Qu, Shaobo; Tan, Dingyin; Tu, Haibo; Wu, Shuchao; Yin, Hang; Li, Hongyin; Zhou, Zebing

2017-01-01

High-precision electrostatic accelerometers have achieved remarkable success in satellite Earth gravity field recovery missions. Ultralow-noise inertial sensors play important roles in space gravitational wave detection missions such as the Laser Interferometer Space Antenna (LISA) mission, and key technologies have been verified in the LISA Pathfinder mission. Meanwhile, at Huazhong University of Science and Technology (HUST, China), a space accelerometer and inertial sensor based on capacitive sensors and the electrostatic control technique have also been studied and developed independently for more than 16 years. In this paper, we review the operational principle, application, and requirements of the electrostatic accelerometer and inertial sensor in different space missions. The development and progress of a space electrostatic accelerometer at HUST, including ground investigation and space verification are presented. PMID:28832538

Ground Testing of Prototype Hardware and Processing Algorithms for a Wide Area Space Surveillance System (WASSS)

DTIC Science & Technology

2013-09-01

Ground testing of prototype hardware and processing algorithms for a Wide Area Space Surveillance System (WASSS) Neil Goldstein, Rainer A...at Magdalena Ridge Observatory using the prototype Wide Area Space Surveillance System (WASSS) camera, which has a 4 x 60 field-of-view , < 0.05...objects with larger-aperture cameras. The sensitivity of the system depends on multi-frame averaging and a Principal Component Analysis based image

Ground Systems Development Environment (GSDE) interface requirements and prototyping plan

NASA Technical Reports Server (NTRS)

Church, Victor E.; Philips, John; Bassman, Mitchell; Williams, C.

1990-01-01

This report describes the data collection and requirements analysis effort of the Ground System Development Environment (GSDE) Interface Requirements study. It identifies potential problems in the interfaces among applications and processors in the heterogeneous systems that comprises the GSDE. It describes possible strategies for addressing those problems. It also identifies areas for further research and prototyping to demonstrate the capabilities and feasibility of those strategies and defines a plan for building the necessary software prototypes.

The 80 kV electrostatic wire septum for AmPS

NASA Astrophysics Data System (ADS)

Vanderlinden, A.; Bijleveld, J. H. M.; Rookhuizen, H. Boer; Bruinsma, P. J. T.; Heine, E.; Lassing, P.; Prins, E.

The characteristics of the wire septum for the Amsterdam Pulse Stretcher (AmPS) are summarized. In the extraction process of the AmPS the extracted beam is intercepted from the circulating beam by the 1 m long electrostatic wire septum. For a bending angle of 4.4 mrad, the maximum anode voltage is 80 kV. The system developed consists of a wire spacing of 0.65 mm between tungsten wires of 50 micrometers diameter. Stainless steel spring wires, bent in a half cylindrical carrier, stretch the septum wires two by two. Prototype tests were successful up to an anode voltage of 120 kV.

Satellite auxiliary-propulsion selection techniques. Addendum: A survey of auxiliary electric propulsion systems

NASA Technical Reports Server (NTRS)

Holcomb, L. B.

1971-01-01

A review of electric thrusters for satellite auxiliary propulsion was conducted at JPL during the past year. Comparisons of the various thrusters for attitude propulsion and east-west and north-south stationkeeping were made based upon performance, mass, power, and demonstrated life. Reliability and cost are also discussed. The method of electrical acceleration of propellant served to divide the thruster systems into two groups: electrostatic and electromagnetic. Ion and colloid thrusters fall within the electrostatically accelerated group while MPD and pulsed plasma thrusters comprise the electromagnetically accelerated group. The survey was confined to research in the United States with accent on flight and flight prototype systems.

Electrostatic dry powder prepregging of carbon fiber

NASA Technical Reports Server (NTRS)

Throne, James L.; Sohn, Min-Seok

1990-01-01

Ultrafine, 5-10 micron polymer-matrix resin powders are directly applied to carbon fiber tows by passing then in an air or nitrogen stream through an electrostatic potential; the particles thus charged will strongly adhere to grounded carbon fibers, and can be subsequently fused to the fiber in a continuously-fed radiant oven. This electrostatic technique derived significant end-use mechanical property advantages from the obviation of solvents, binders, and other adulterants. Additional matrix resins used to produce prepregs to date have been PMR-15, Torlon 40000, and LaRC TPI.

Prototype space erectable radiator system ground test article development

NASA Technical Reports Server (NTRS)

Alario, Joseph P.

1988-01-01

A prototype heat rejecting system is being developed by NASA-JSC for possible space station applications. This modular system, the Space-Erectable Radiator System Ground Test Article (SERS-GTA) with high-capacity radiator panels, can be installed and replaced on-orbit. The design, fabrication and testing of a representative ground test article are discussed. Acceptance test data for the heat pipe radiator panel and the whiffletree clamping mechanism have been presented.

Electrostatics-Driven Hierarchical Buckling of Charged Flexible Ribbons.

PubMed

Yao, Zhenwei; Olvera de la Cruz, Monica

2016-04-08

We investigate the rich morphologies of an electrically charged flexible ribbon, which is a prototype for many beltlike structures in biology and nanomaterials. Long-range electrostatic repulsion is found to govern the hierarchical buckling of the ribbon from its initially flat shape to its undulated and out-of-plane twisted conformations. In this process, the screening length is the key controlling parameter, suggesting that a convenient way to manipulate the ribbon morphology is simply to change the salt concentration. We find that these shapes originate from the geometric effect of the electrostatic interaction, which fundamentally changes the metric over the ribbon surface. We also identify the basic modes by which the ribbon reshapes itself in order to lower the energy. The geometric effect of the physical interaction revealed in this Letter has implications for the shape design of extensive ribbonlike materials in nano- and biomaterials.

Design, Fabrication and Levitation Experiments of a Micromachined Electrostatically Suspended Six-Axis Accelerometer

PubMed Central

Cui, Feng; Liu, Wu; Chen, Wenyuan; Zhang, Weiping; Wu, Xiaosheng

2011-01-01

A micromachined electrostatically suspended six-axis accelerometer, with a square plate as proof mass housed by a top stator and bottom stator, is presented. The device structure and related techniques concerning its operating principles, such as calculation of capacitances and electrostatic forces/moments, detection and levitation control of the proof mass, acceleration measurement, and structural parameters design, are described. Hybrid MEMS manufacturing techniques, including surface micromachining fabrication of thin film electrodes and interconnections, integration fabrication of thick nickel structures about 500 μm using UV-LIGA by successful removal of SU-8 photoresist mold, DRIE of silicon proof mass in thickness of 450 μm, microassembly and solder bonding, were employed to fabricate this prototype microdevice. A levitation experiment system for the fabricated microaccelerometer chip is introduced, and levitation results show that fast initial levitation within 10 ms and stable full suspension of the proof mass have been successfully demonstrated. PMID:22247662

Prototype of NASA's Global Precipitation Measurement Mission Ground Validation System

NASA Technical Reports Server (NTRS)

Schwaller, M. R.; Morris, K. R.; Petersen, W. A.

2007-01-01

NASA is developing a Ground Validation System (GVS) as one of its contributions to the Global Precipitation Mission (GPM). The GPM GVS provides an independent means for evaluation, diagnosis, and ultimately improvement of GPM spaceborne measurements and precipitation products. NASA's GPM GVS consists of three elements: field campaigns/physical validation, direct network validation, and modeling and simulation. The GVS prototype of direct network validation compares Tropical Rainfall Measuring Mission (TRMM) satellite-borne radar data to similar measurements from the U.S. national network of operational weather radars. A prototype field campaign has also been conducted; modeling and simulation prototypes are under consideration.

Experimental validation of prototype high voltage bushing

NASA Astrophysics Data System (ADS)

Shah, Sejal; Tyagi, H.; Sharma, D.; Parmar, D.; M. N., Vishnudev; Joshi, K.; Patel, K.; Yadav, A.; Patel, R.; Bandyopadhyay, M.; Rotti, C.; Chakraborty, A.

2017-08-01

Prototype High voltage bushing (PHVB) is a scaled down configuration of DNB High Voltage Bushing (HVB) of ITER. It is designed for operation at 50 kV DC to ensure operational performance and thereby confirming the design configuration of DNB HVB. Two concentric insulators viz. Ceramic and Fiber reinforced polymer (FRP) rings are used as double layered vacuum boundary for 50 kV isolation between grounded and high voltage flanges. Stress shields are designed for smooth electric field distribution. During ceramic to Kovar brazing, spilling cannot be controlled which may lead to high localized electrostatic stress. To understand spilling phenomenon and precise stress calculation, quantitative analysis was performed using Scanning Electron Microscopy (SEM) of brazed sample and similar configuration modeled while performing the Finite Element (FE) analysis. FE analysis of PHVB is performed to find out electrical stresses on different areas of PHVB and are maintained similar to DNB HV Bushing. With this configuration, the experiment is performed considering ITER like vacuum and electrical parameters. Initial HV test is performed by temporary vacuum sealing arrangements using gaskets/O-rings at both ends in order to achieve desired vacuum and keep the system maintainable. During validation test, 50 kV voltage withstand is performed for one hour. Voltage withstand test for 60 kV DC (20% higher rated voltage) have also been performed without any breakdown. Successful operation of PHVB confirms the design of DNB HV Bushing. In this paper, configuration of PHVB with experimental validation data is presented.

First-principles calculated decomposition pathways for LiBH4 nanoclusters

PubMed Central

Huang, Zhi-Quan; Chen, Wei-Chih; Chuang, Feng-Chuan; Majzoub, Eric H.; Ozoliņš, Vidvuds

2016-01-01

We analyze thermodynamic stability and decomposition pathways of LiBH4 nanoclusters using grand-canonical free-energy minimization based on total energies and vibrational frequencies obtained from density-functional theory (DFT) calculations. We consider (LiBH4)n nanoclusters with n = 2 to 12 as reactants, while the possible products include (Li)n, (B)n, (LiB)n, (LiH)n, and Li2BnHn; off-stoichiometric LinBnHm (m ≤ 4n) clusters were considered for n = 2, 3, and 6. Cluster ground-state configurations have been predicted using prototype electrostatic ground-state (PEGS) and genetic algorithm (GA) based structural optimizations. Free-energy calculations show hydrogen release pathways markedly differ from those in bulk LiBH4. While experiments have found that the bulk material decomposes into LiH and B, with Li2B12H12 as a kinetically inhibited intermediate phase, (LiBH4)n nanoclusters with n ≤ 12 are predicted to decompose into mixed LinBn clusters via a series of intermediate clusters of LinBnHm (m ≤ 4n). The calculated pressure-composition isotherms and temperature-pressure isobars exhibit sloping plateaus due to finite size effects on reaction thermodynamics. Generally, decomposition temperatures of free-standing clusters are found to increase with decreasing cluster size due to thermodynamic destabilization of reaction products. PMID:27189731

First-principles calculated decomposition pathways for LiBH 4 nanoclusters

DOE PAGES

Huang, Zhi -Quan; Chen, Wei -Chih; Chuang, Feng -Chuan; ...

2016-05-18

Here, we analyze thermodynamic stability and decomposition pathways of LiBH 4 nanoclusters using grand-canonical free-energy minimization based on total energies and vibrational frequencies obtained from density-functional theory (DFT) calculations. We consider (LiBH 4) n nanoclusters with n = 2 to 12 as reactants, while the possible products include (Li) n, (B) n, (LiB) n, (LiH) n, and Li 2B nH n; off-stoichiometric LinBnHm (m ≤ 4n) clusters were considered for n = 2, 3, and 6. Cluster ground-state configurations have been predicted using prototype electrostatic ground-state (PEGS) and genetic algorithm (GA) based structural optimizations. Free-energy calculations show hydrogen release pathwaysmore » markedly differ from those in bulk LiBH 4. While experiments have found that the bulk material decomposes into LiH and B, with Li 2B 12H 12 as a kinetically inhibited intermediate phase, (LiBH 4) n nanoclusters with n ≤ 12 are predicted to decompose into mixed Li nB n clusters via a series of intermediate clusters of Li nB nH m (m ≤ 4n). The calculated pressure-composition isotherms and temperature-pressure isobars exhibit sloping plateaus due to finite size effects on reaction thermodynamics. Generally, decomposition temperatures of free-standing clusters are found to increase with decreasing cluster size due to thermodynamic destabilization of reaction products.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Zhi -Quan; Chen, Wei -Chih; Chuang, Feng -Chuan

Here, we analyze thermodynamic stability and decomposition pathways of LiBH 4 nanoclusters using grand-canonical free-energy minimization based on total energies and vibrational frequencies obtained from density-functional theory (DFT) calculations. We consider (LiBH 4) n nanoclusters with n = 2 to 12 as reactants, while the possible products include (Li) n, (B) n, (LiB) n, (LiH) n, and Li 2B nH n; off-stoichiometric LinBnHm (m ≤ 4n) clusters were considered for n = 2, 3, and 6. Cluster ground-state configurations have been predicted using prototype electrostatic ground-state (PEGS) and genetic algorithm (GA) based structural optimizations. Free-energy calculations show hydrogen release pathwaysmore » markedly differ from those in bulk LiBH 4. While experiments have found that the bulk material decomposes into LiH and B, with Li 2B 12H 12 as a kinetically inhibited intermediate phase, (LiBH 4) n nanoclusters with n ≤ 12 are predicted to decompose into mixed Li nB n clusters via a series of intermediate clusters of Li nB nH m (m ≤ 4n). The calculated pressure-composition isotherms and temperature-pressure isobars exhibit sloping plateaus due to finite size effects on reaction thermodynamics. Generally, decomposition temperatures of free-standing clusters are found to increase with decreasing cluster size due to thermodynamic destabilization of reaction products.« less

Advanced hybrid particulate collector and method of operation

DOEpatents

Miller, Stanley J [Grand Forks, ND

2003-04-08

A device and method for controlling particulate air pollutants of the present invention combines filtration and electrostatic collection devices. The invention includes a chamber housing a plurality of rows of filter elements. Between the rows of filter elements are rows of high voltage discharge electrodes. Between the rows of discharge electrodes and the rows of filter elements are grounded perforated plates for creating electrostatic precipitation zones.

An improved model for computing the trajectories of conductive particles in roll-type electrostatic separator for recycling metals from WEEE.

PubMed

Wu, Jiang; Li, Jia; Xu, Zhenming

2009-08-15

Electrostatic separation presents an effective and environmentally friendly way for recycling metals and nonmetals from ground waste electrical and electronic equipment (WEEE). For this process, the trajectory of conductive particle is significant and some models have been established. However, the results of previous researches are limited by some simplifying assumptions and lead to a notable discrepancy between the model prediction and the experimental results. In the present research, a roll-type corona-electrostatic separator and ground printed circuit board (PCB) wastes were used to investigate the trajectory of the conductive particle. Two factors, the air drag force and the different charging situation, were introduced into the improved model. Their effects were analyzed and an improved model for the theoretical trajectory of conductive particle was established. Compared with the previous one, the improved model shows a good agreement with the experimental results. It provides a positive guidance for designing of separator and makes a progress for recycling the metals and nonmetals from WEEE.

The 1991 International Aerospace and Ground Conference on Lightning and Static Electricity, volume 1

NASA Technical Reports Server (NTRS)

1991-01-01

The proceedings of the 1991 International Aerospace and Ground Conference on Lightning and Static Electricity are reported. Some of the topics covered include: lightning, lightning suppression, aerospace vehicles, aircraft safety, flight safety, aviation meteorology, thunderstorms, atmospheric electricity, warning systems, weather forecasting, electromagnetic coupling, electrical measurement, electrostatics, aircraft hazards, flight hazards, meteorological parameters, cloud (meteorology), ground effect, electric currents, lightning equipment, electric fields, measuring instruments, electrical grounding, and aircraft instruments.

Nondestructive Inspection System for Special Nuclear Material Using Inertial Electrostatic Confinement Fusion Neutrons and Laser Compton Scattering Gamma-Rays

NASA Astrophysics Data System (ADS)

Ohgaki, H.; Daito, I.; Zen, H.; Kii, T.; Masuda, K.; Misawa, T.; Hajima, R.; Hayakawa, T.; Shizuma, T.; Kando, M.; Fujimoto, S.

2017-07-01

A Neutron/Gamma-ray combined inspection system for hidden special nuclear materials (SNMs) in cargo containers has been developed under a program of Japan Science and Technology Agency in Japan. This inspection system consists of an active neutron-detection system for fast screening and a laser Compton backscattering gamma-ray source in coupling with nuclear resonance fluorescence (NRF) method for precise inspection. The inertial electrostatic confinement fusion device has been adopted as a neutron source and two neutron-detection methods, delayed neutron noise analysis method and high-energy neutron-detection method, have been developed to realize the fast screening system. The prototype system has been constructed and tested in the Reactor Research Institute, Kyoto University. For the generation of the laser Compton backscattering gamma-ray beam, a race track microtron accelerator has been used to reduce the size of the system. For the NRF measurement, an array of LaBr3(Ce) scintillation detectors has been adopted to realize a low-cost detection system. The prototype of the gamma-ray system has been demonstrated in the Kansai Photon Science Institute, National Institutes for Quantum and Radiological Science and Technology. By using numerical simulations based on the data taken from these prototype systems and the inspection-flow, the system designed by this program can detect 1 kg of highly enriched 235U (HEU) hidden in an empty 20-ft container within several minutes.

Investigation of spatial resolution and temporal performance of SAPHIRE (scintillator avalanche photoconductor with high resolution emitter readout) with integrated electrostatic focusing

NASA Astrophysics Data System (ADS)

Scaduto, David A.; Lubinsky, Anthony R.; Rowlands, John A.; Kenmotsu, Hidenori; Nishimoto, Norihito; Nishino, Takeshi; Tanioka, Kenkichi; Zhao, Wei

2014-03-01

We have previously proposed SAPHIRE (scintillator avalanche photoconductor with high resolution emitter readout), a novel detector concept with potentially superior spatial resolution and low-dose performance compared with existing flat-panel imagers. The detector comprises a scintillator that is optically coupled to an amorphous selenium photoconductor operated with avalanche gain, known as high-gain avalanche rushing photoconductor (HARP). High resolution electron beam readout is achieved using a field emitter array (FEA). This combination of avalanche gain, allowing for very low-dose imaging, and electron emitter readout, providing high spatial resolution, offers potentially superior image quality compared with existing flat-panel imagers, with specific applications to fluoroscopy and breast imaging. Through the present collaboration, a prototype HARP sensor with integrated electrostatic focusing and nano- Spindt FEA readout technology has been fabricated. The integrated electron-optic focusing approach is more suitable for fabricating large-area detectors. We investigate the dependence of spatial resolution on sensor structure and operating conditions, and compare the performance of electrostatic focusing with previous technologies. Our results show a clear dependence of spatial resolution on electrostatic focusing potential, with performance approaching that of the previous design with external mesh-electrode. Further, temporal performance (lag) of the detector is evaluated and the results show that the integrated electrostatic focusing design exhibits comparable or better performance compared with the mesh-electrode design. This study represents the first technical evaluation and characterization of the SAPHIRE concept with integrated electrostatic focusing.

Ares I-X Ground Diagnostic Prototype

NASA Technical Reports Server (NTRS)

Schwabacher, Mark; Martin, Rodney; Waterman, Robert; Oostdyk, Rebecca; Ossenfort, John; Matthews, Bryan

2010-01-01

Automating prelaunch diagnostics for launch vehicles offers three potential benefits. First, it potentially improves safety by detecting faults that might otherwise have been missed so that they can be corrected before launch. Second, it potentially reduces launch delays by more quickly diagnosing the cause of anomalies that occur during prelaunch processing. Reducing launch delays will be critical to the success of NASA's planned future missions that require in-orbit rendezvous. Third, it potentially reduces costs by reducing both launch delays and the number of people needed to monitor the prelaunch process. NASA is currently developing the Ares I launch vehicle to bring the Orion capsule and its crew of four astronauts to low-earth orbit on their way to the moon. Ares I-X will be the first unmanned test flight of Ares I. It is scheduled to launch on October 27, 2009. The Ares I-X Ground Diagnostic Prototype is a prototype ground diagnostic system that will provide anomaly detection, fault detection, fault isolation, and diagnostics for the Ares I-X first-stage thrust vector control (TVC) and for the associated ground hydraulics while it is in the Vehicle Assembly Building (VAB) at John F. Kennedy Space Center (KSC) and on the launch pad. It will serve as a prototype for a future operational ground diagnostic system for Ares I. The prototype combines three existing diagnostic tools. The first tool, TEAMS (Testability Engineering and Maintenance System), is a model-based tool that is commercially produced by Qualtech Systems, Inc. It uses a qualitative model of failure propagation to perform fault isolation and diagnostics. We adapted an existing TEAMS model of the TVC to use for diagnostics and developed a TEAMS model of the ground hydraulics. The second tool, Spacecraft Health Inference Engine (SHINE), is a rule-based expert system developed at the NASA Jet Propulsion Laboratory. We developed SHINE rules for fault detection and mode identification. The prototype uses the outputs of SHINE as inputs to TEAMS. The third tool, the Inductive Monitoring System (IMS), is an anomaly detection tool developed at NASA Ames Research Center and is currently used to monitor the International Space Station Control Moment Gyroscopes. IMS automatically "learns" a model of historical nominal data in the form of a set of clusters and signals an alarm when new data fails to match this model. IMS offers the potential to detect faults that have not been modeled. The three tools have been integrated and deployed to Hangar AE at KSC where they interface with live data from the Ares I-X vehicle and from the ground hydraulics. The outputs of the tools are displayed on a console in Hangar AE, one of the locations from which the Ares I-X launch will be monitored. The full paper will describe how the prototype performed before the launch. It will include an analysis of the prototype's accuracy, including false-positive rates, false-negative rates, and receiver operating characteristics (ROC) curves. It will also include a description of the prototype's computational requirements, including CPU usage, main memory usage, and disk usage. If the prototype detects any faults during the prelaunch period then the paper will include a description of those faults. Similarly, if the prototype has any false alarms then the paper will describe them and will attempt to explain their causes.

Status of the planar electrostatic gradiometer GREMLIT for airborne geodesy

NASA Astrophysics Data System (ADS)

Boulanger, D.; Foulon, B.; Lebat, V.; Bresson, A.; Christophe, B.

2016-12-01

Taking advantage of technologies, developed by ONERA for the GRACE and GOCE space missions, the GREMLIT airborne gravity gradiometer is based of a planar electrostatic gradiometer configuration. The feasibility of the instrument and of its performance was proved by realistic simulations, based on actual data and recorded environmental aircraft perturbations, with performance of about one Eötvös along the two horizontal components of the gravity gradient. In order to assess the operation of the electrostatic gradiometer on its associated stabilized platform, a one axis prototype has also been built. The next step is the realization of the stabilization platform, controlled by the common mode outputs of the instrument itself, in order to reject the perturbations induced by the airborne environment in the horizontal directions. One of the interests of the GREMLIT instrument is the possibility of an easy hybrid configuration with a vertical one axis Cold Atoms Interferometer gravity gradiometer called GIBON and also under development at ONERA. In such hybrid instrument, The CAI instrument takes also advantage of the platform stabilized by the electrostatic one. The poster will emphasize the status of realization of the instrument and of its stabilized platform.

Monolithic integrated circuit charge amplifier and comparator for MAMA readout

NASA Technical Reports Server (NTRS)

Cole, Edward H.; Smeins, Larry G.

1991-01-01

Prototype ICs for the Solar Heliospheric Observatory's Multi-Anode Microchannel Array (MAMA) have been developed; these ICs' charge-amplifier and comparator components were then tested with a view to pulse response and noise performance. All model performance predictions have been exceeded. Electrostatic discharge protection has been included on all IC connections; device operation over temperature has been consistent with model predictions.

Fabrication and characterization of resonant SOI micromechanical silicon sensors based on DRIE micromachining, freestanding release process and silicon direct bonding

NASA Astrophysics Data System (ADS)

Gigan, Olivier; Chen, Hua; Robert, Olivier; Renard, Stephane; Marty, Frederic

2002-11-01

This paper is dedicated to the fabrication and technological aspect of a silicon microresonator sensor. The entire project includes the fabrication processes, the system modelling/simulation, and the electronic interface. The mechanical model of such resonator is presented including description of frequency stability and Hysterises behaviour of the electrostatically driven resonator. Numeric model and FEM simulations are used to simulate the system dynamic behaviour. The complete fabrication process is based on standard microelectronics technology with specific MEMS technological steps. The key steps are described: micromachining on SOI by Deep Reactive Ion Etching (DRIE), specific release processes to prevent sticking (resist and HF-vapour release process) and collective vacuum encapsulation by Silicon Direct Bonding (SDB). The complete process has been validated and prototypes have been fabricated. The ASIC was designed to interface the sensor and to control the vibration amplitude. This electronic was simulated and designed to work up to 200°C and implemented in a standard 0.6μ CMOS technology. Characterizations of sensor prototypes are done both mechanically and electrostatically. These measurements showed good agreements with theory and FEM simulations.

Characterizing the Performance of the Wheel Electrostatic Spectrometer

NASA Technical Reports Server (NTRS)

Johansen, M. R.; Mackey, P. J.; Holbert, E.; Clements, J. S.; Calle, C. I.

2013-01-01

A Wheel Electrostatic Spectrometer has been developed as a surveying tool to be incorporated into a Martian rover design. Electrostatic sensors with various protruding cover insulators are embedded into a prototype rover wheel. When these insulators come into contact with a surface, a charge develops on the cover insulator through tribocharging. A charge spectrum is created by analyzing the accumulated charge on each of the dissimilar cover insulators. This charge spectrum can be used to determine differences in Martian regolith properties. In this study, we analyzed the repeatability of the measurements for this sensor package and found that the sensor repeatability lies within one standard deviation of the noise in the signal. In addition, we tested the need for neutralizing the surface charge on the cover insulators and discovered a need to discharge the sensor cover insulators after each revolution. Future work includes an electronics redesign to reduce noise and a Martian pressure static elimination tool that can be used to neutralize the charge on the sensor cover insulators after each wheel revolution.

Integration of a satellite ground support system based on analysis of the satellite ground support domain

NASA Technical Reports Server (NTRS)

Pendley, R. D.; Scheidker, E. J.; Levitt, D. S.; Myers, C. R.; Werking, R. D.

1994-01-01

This analysis defines a complete set of ground support functions based on those practiced in real space flight operations during the on-orbit phase of a mission. These functions are mapped against ground support functions currently in use by NASA and DOD. Software components to provide these functions can be hosted on RISC-based work stations and integrated to provide a modular, integrated ground support system. Such modular systems can be configured to provide as much ground support functionality as desired. This approach to ground systems has been widely proposed and prototyped both by government institutions and commercial vendors. The combined set of ground support functions we describe can be used as a standard to evaluate candidate ground systems. This approach has also been used to develop a prototype of a modular, loosely-integrated ground support system, which is discussed briefly. A crucial benefit to a potential user is that all the components are flight-qualified, thus giving high confidence in their accuracy and reliability.

Integration of a satellite ground support system based on analysis of the satellite ground support domain

NASA Astrophysics Data System (ADS)

Pendley, R. D.; Scheidker, E. J.; Levitt, D. S.; Myers, C. R.; Werking, R. D.

1994-11-01

This analysis defines a complete set of ground support functions based on those practiced in real space flight operations during the on-orbit phase of a mission. These functions are mapped against ground support functions currently in use by NASA and DOD. Software components to provide these functions can be hosted on RISC-based work stations and integrated to provide a modular, integrated ground support system. Such modular systems can be configured to provide as much ground support functionality as desired. This approach to ground systems has been widely proposed and prototyped both by government institutions and commercial vendors. The combined set of ground support functions we describe can be used as a standard to evaluate candidate ground systems. This approach has also been used to develop a prototype of a modular, loosely-integrated ground support system, which is discussed briefly. A crucial benefit to a potential user is that all the components are flight-qualified, thus giving high confidence in their accuracy and reliability.

Including diverging electrostatic potential in 3D-RISM theory: The charged wall case.

PubMed

Vyalov, Ivan; Rocchia, Walter

2018-03-21

Although three-dimensional site-site molecular integral equations of liquids are a powerful tool of the modern theoretical chemistry, their applications to the problem of characterizing the electrical double layer originating at the solid-liquid interface with a macroscopic substrate are severely limited by the fact that an infinitely extended charged plane generates a divergent electrostatic potential. Such potentials cannot be treated within the standard 3D-Reference Interaction Site Model equation solution framework since it leads to functions that are not Fourier transformable. In this paper, we apply a renormalization procedure to overcome this obstacle. We then check the validity and numerical accuracy of the proposed computational scheme on the prototypical gold (111) surface in contact with water/alkali chloride solution. We observe that despite the proposed method requires, to achieve converged charge densities, a higher spatial resolution than that suited to the estimation of biomolecular solvation with either 3D-RISM or continuum electrostatics approaches, it still is computationally efficient. Introducing the electrostatic potential of an infinite wall, which is periodic in 2 dimensions, we avoid edge effects, permit a robust integration of Poisson's equation, and obtain the 3D electrostatic potential profile for the first time in such calculations. We show that the potential within the electrical double layer presents oscillations which are not grasped by the Debye-Hückel and Gouy-Chapman theories. This electrostatic potential deviates from its average of up to 1-2 V at small distances from the substrate along the lateral directions. Applications of this theoretical development are relevant, for example, for liquid scanning tunneling microscopy imaging.

Including diverging electrostatic potential in 3D-RISM theory: The charged wall case

NASA Astrophysics Data System (ADS)

Vyalov, Ivan; Rocchia, Walter

2018-03-01

Although three-dimensional site-site molecular integral equations of liquids are a powerful tool of the modern theoretical chemistry, their applications to the problem of characterizing the electrical double layer originating at the solid-liquid interface with a macroscopic substrate are severely limited by the fact that an infinitely extended charged plane generates a divergent electrostatic potential. Such potentials cannot be treated within the standard 3D-Reference Interaction Site Model equation solution framework since it leads to functions that are not Fourier transformable. In this paper, we apply a renormalization procedure to overcome this obstacle. We then check the validity and numerical accuracy of the proposed computational scheme on the prototypical gold (111) surface in contact with water/alkali chloride solution. We observe that despite the proposed method requires, to achieve converged charge densities, a higher spatial resolution than that suited to the estimation of biomolecular solvation with either 3D-RISM or continuum electrostatics approaches, it still is computationally efficient. Introducing the electrostatic potential of an infinite wall, which is periodic in 2 dimensions, we avoid edge effects, permit a robust integration of Poisson's equation, and obtain the 3D electrostatic potential profile for the first time in such calculations. We show that the potential within the electrical double layer presents oscillations which are not grasped by the Debye-Hückel and Gouy-Chapman theories. This electrostatic potential deviates from its average of up to 1-2 V at small distances from the substrate along the lateral directions. Applications of this theoretical development are relevant, for example, for liquid scanning tunneling microscopy imaging.

Ares I-X Ground Diagnostic Prototype

NASA Technical Reports Server (NTRS)

Schwabacher, Mark A.; Martin, Rodney Alexander; Waterman, Robert D.; Oostdyk, Rebecca Lynn; Ossenfort, John P.; Matthews, Bryan

2010-01-01

The automation of pre-launch diagnostics for launch vehicles offers three potential benefits: improving safety, reducing cost, and reducing launch delays. The Ares I-X Ground Diagnostic Prototype demonstrated anomaly detection, fault detection, fault isolation, and diagnostics for the Ares I-X first-stage Thrust Vector Control and for the associated ground hydraulics while the vehicle was in the Vehicle Assembly Building at Kennedy Space Center (KSC) and while it was on the launch pad. The prototype combines three existing tools. The first tool, TEAMS (Testability Engineering and Maintenance System), is a model-based tool from Qualtech Systems Inc. for fault isolation and diagnostics. The second tool, SHINE (Spacecraft Health Inference Engine), is a rule-based expert system that was developed at the NASA Jet Propulsion Laboratory. We developed SHINE rules for fault detection and mode identification, and used the outputs of SHINE as inputs to TEAMS. The third tool, IMS (Inductive Monitoring System), is an anomaly detection tool that was developed at NASA Ames Research Center. The three tools were integrated and deployed to KSC, where they were interfaced with live data. This paper describes how the prototype performed during the period of time before the launch, including accuracy and computer resource usage. The paper concludes with some of the lessons that we learned from the experience of developing and deploying the prototype.

Method for electrostatic deposition of graphene on a substrate

NASA Technical Reports Server (NTRS)

Sumanasekera, Gamini (Inventor); Sidorov, Anton N. (Inventor); Ouseph, P. John (Inventor); Yazdanpanah, Mehdi M. (Inventor); Cohn, Robert W. (Inventor); Jalilian, Romaneh (Inventor)

2010-01-01

A method for electrostatic deposition of graphene on a substrate comprises the steps of securing a graphite sample to a first electrode; electrically connecting the first electrode to a positive terminal of a power source; electrically connecting a second electrode to a ground terminal of the power source; placing the substrate over the second electrode; and using the power source to apply a voltage, such that graphene is removed from the graphite sample and deposited on the substrate.

Experiments Using a Ground-Based Electrostatic Levitator and Numerical Modeling of Melt Convection for the Iron-Cobalt System in Support of Space Experiments

NASA Astrophysics Data System (ADS)

Lee, Jonghyun; SanSoucie, Michael P.

2017-08-01

Materials research is being conducted using an electromagnetic levitator installed in the International Space Station. Various metallic alloys were tested to elucidate unknown links among the structures, processes, and properties. To accomplish the mission of these space experiments, several ground-based activities have been carried out. This article presents some of our ground-based supporting experiments and numerical modeling efforts. Mass evaporation of Fe50Co50, one of flight compositions, was predicted numerically and validated by the tests using an electrostatic levitator (ESL). The density of various compositions within the Fe-Co system was measured with ESL. These results are being served as reference data for the space experiments. The convection inside a electromagnetically-levitated droplet was also modeled to predict the flow status, shear rate, and convection velocity under various process parameters, which is essential information for designing and analyzing the space experiments of some flight compositions influenced by convection.

Low power interface IC's for electrostatic energy harvesting applications

NASA Astrophysics Data System (ADS)

Kempitiya, Asantha

The application of wireless distributed micro-sensor systems ranges from equipment diagnostic and control to real time structural and biomedical monitoring. A major obstacle in developing autonomous micro-sensor networks is the need for local electric power supply, since using a battery is often not a viable solution. This void has sparked significant interest in micro-scale power generators based on electrostatic, piezoelectric and electromagnetic energy conversion that can scavenge ambient energy from the environment. In comparison to existing energy harvesting techniques, electrostatic-based power generation is attractive as it can be integrated using mainstream silicon technologies while providing higher power densities through miniaturization. However the power output of reported electrostatic micro-generators to date does not meet the communication and computation requirements of wireless sensor nodes. The objective of this thesis is to investigate novel CMOS-based energy harvesting circuit (EHC) architectures to increase the level of harvested mechanical energy in electrostatic converters. The electronic circuits that facilitate mechanical to electrical energy conversion employing variable capacitors can either have synchronous or asynchronous architectures. The later does not require synchronization of electrical events with mechanical motion, which eliminates difficulties in gate clocking and the power consumption associated with complex control circuitry. However, the implementation of the EHC with the converter can be detrimental to system performance when done without concurrent optimization of both elements, an aspect mainly overlooked in the literature. System level analysis is performed to show that there is an optimum value for either the storage capacitor or cycle number for maximum scavenging of ambient energy. The analysis also shows that maximum power is extracted when the system approaches synchronous operation. However, there is a region of interest where the storage capacitor can be optimized to produce almost 70% of the ideal power taken as the power harvested with synchronous converters when neglecting the power consumption associated with synchronizing control circuitry. Theoretical predictions are confirmed by measurements on an asynchronous EHC implemented with a macro-scale electrostatic converter prototype. Based on the preceding analysis, the design of a novel ultra low power electrostatic integrated energy harvesting circuit is proposed for efficient harvesting of mechanical energy. The fundamental challenges of designing reliable low power sensing circuits for charge constrained electrostatic energy harvesters with capacity to self power its controller and driver stages are addressed. Experimental results are presented for a controller design implemented in AMI 0.7muM high voltage CMOS process using a macro-scale electrostatic converter prototype. The EHC produces 1.126muW for a power investment of 417nW with combined conduction and controller losses of 450nW which is a 20-30% improvement compared to prior art on electrostatic EHCs operating under charge constrain. Inherently dual plate variable capacitors harvest energy only during half of the mechanical cycle with the other half unutilized for energy conversion. To harvest mechanical energy over the complete mechanical vibration cycle, a low power energy harvesting circuit (EHC) that performs charge constrained synchronous energy conversion on a tri-plate variable capacitor for maximizing energy conversion is proposed. The tri-plate macro electrostatic generator with capacitor variation of 405pF to 1.15nF and 405pF to 1.07nF on two complementary adjacent capacitors is fabricated and used in the characterization of the designed EHC. The integrated circuit fabricated in AMI 0.7muM high voltage CMOS process, produces a total output power of 497nW to a 10muF reservoir capacitor from a 98Hz vibration signal. In summary, the thesis lays out the theoretical and experimental foundation for overcoming the main challenges associated with the design of charge constrained synchronous EHC's, making electrostatic converters a possible candidate for powering emerging communication transceivers and portable electronics.

Protonation states and pH titration in the photocycle of photoactive yellow protein.

PubMed

Demchuk, E; Genick, U K; Woo, T T; Getzoff, E D; Bashford, D

2000-02-08

Photoactive yellow protein (PYP) undergoes a light-driven cycle of color and protonation states that is part of a mechanism of bacterial phototaxis. This article concerns functionally important protonation states of PYP and the interactions that stabilize them, and changes in the protonation state during the photocycle. In particular, the chromophore pK(a) is known to be shifted down so that the chromophore is negatively charged in the ground state (dark state) even though it is buried in the protein, while nearby Glu46 has an unusually high pK(a). The photocycle involves changes of one or both of these protonation states. Calculations of pK(a) values and protonation states using a semi-macroscopic electrostatic model are presented for the wild-type and three mutants, in both the ground state and the bleached (I(2)) intermediate state. Calculations allowing multiple H-bonding arrangements around the chromophore also have been carried out. In addition, ground-state pK(a) values of the chromophore have been measured by UV-visible spectroscopy for the wild-type and the same three mutants. Because of the unusual protonation states and strong electrostatic interactions, PYP represents a severe test of the ability of theoretical models to yield correct calculations of electrostatic interactions in proteins. Good agreement between experiment and theory can be obtained for the ground state provided the protein interior is assumed to have a relatively low dielectric constant, but only partial agreement between theory and experiment is obtained for the bleached state. We also present a reinterpretation of previously published data on the pH-dependence of the recovery of the ground state from the bleached state. The new analysis implies a pK(a) value of 6.37 for Glu46 in the bleached state, which is consistent with other available experimental data, including data that only became available after this analysis. The new analysis suggests that signal transduction is modulated by the titration properties of the bleached state, which are in turn determined by electrostatic interactions. Overall, the results of this study provide a quantitative picture of the interactions responsible for the unusual protonation states of the chromophore and Glu46, and of protonation changes upon bleaching.

High mass resolution, high angular acceptance time-of-flight mass spectroscopy for planetary missions under the Planetary Instrument Definition and Development Program (PIDDP)

NASA Technical Reports Server (NTRS)

Young, David T.

1991-01-01

This final report covers three years and several phases of work in which instrumentation for the Planetary Instrument Definition and Development Program (PIDDP) were successfully developed. There were two main thrusts to this research: (1) to develop and test methods for electrostatically scanning detector field-of-views, and (2) to improve the mass resolution of plasma mass spectrometers to M/delta M approximately 25, their field-of-view (FOV) to 360 degrees, and their E-range to cover approximately 1 eV to 50 keV. Prototypes of two different approaches to electrostatic scanning were built and tested. The Isochronous time-of-flight (TOF) and the linear electric field 3D TOF devices were examined.

Triboelectret-based aeroelastic flutter energy harvesters

NASA Astrophysics Data System (ADS)

Perez, Matthias; Boisseau, Sebastien; Geisler, Matthias; Despesse, Ghislain; Reboud, Jean Luc

2016-11-01

This paper highlights some experimental results on several electrostatic membranes tested in a wind tunnel between 0 and 20m.s-1 for airflow energy harvesting. The main idea is to use the aeroelastic behavior of thin flexible films to induce simultaneously the capacitance variations and the polarization required by the triboelectric/electrostatic conversion. This technology provides thin and flexible devices and avoids the issue of electrets discharge. Our prototypes (<16cm2) allowed a quick startup (from 3ms-1), an electrical power-flux density from 0.1μW.cm-2 to 60μW.cm-2. In order to complete the energy harvesting chain, we have used a wireless sensor with temperature and acceleration measures coupled to a low power transmission (Bluetooth Low Energy) with reception on a smartphone.

Electrostatic Precipitation of Dust in the Martian Atmosphere: Implications for the Utilization of Resources During Future Manned Exploration Missions

NASA Technical Reports Server (NTRS)

Calle, Carlos I.; Clements, Judson S.; Thompson, Samuel M.; Cox, Nathan D.; Hogue, Michael D.; Johansen, Michael R.; Williams, Blakeley S.

2011-01-01

Future human missions to Mars will require the utilization of local resources for oxygen, fuel. and water. The In Situ Resource Utilization (ISRU) project is an active research endeavor at NASA to develop technologies that can enable cost effective ways to live off the land. The extraction of oxygen from the Martian atmosphere. composed primarily of carbon dioxide, is one of the most important goals of the Mars ISRU project. The main obstacle is the relatively large amount of dust present in the Martian atmosphere. This dust must be efficiently removed from atmospheric gas intakes for ISRU processing chambers. A common technique to achieve this removal on earth is by electrostatic precipitation, where large electrostatic fields are established in a localized region to precipitate and collect previously charged dust particles. This technique is difficult to adapt to the Martian environment, with an atmospheric pressure of about one-hundredth of the terrestrial atmosphere. At these low pressures. the corona discharges required to implant an electrostatic charge to the particles to be collected is extremely difficult to sustain and the corona easily becomes biopolar. which is unsuitable for particle charging. In this paper, we report on our successful efforts to establish a stable corona under Martian simulated conditions. We also present results on dust collecting efficiencies with an electrostatic precipitator prototype that could be effectively used on a future mission to the red planet

Prototype active scanner for nighttime oil spill mapping and classification

NASA Technical Reports Server (NTRS)

Sandness, G. A.; Ailes, S. B.

1977-01-01

A prototype, active, aerial scanner system was constructed for nighttime water pollution detection and nighttime multispectral imaging of the ground. An arc lamp was used to produce the transmitted light and four detector channels provided a multispectral measurement capability. The feasibility of the design concept was demonstrated by laboratory and flight tests of the prototype system.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernardin, John D; Baca, Allen G

This paper presents the mechanical design, fabrication and dynamic testing of an electrostatic analyzer spacecraft instrument. The functional and environmental requirements combined with limited spacecraft accommodations, resulted in complex component geometries, unique material selections, and difficult fabrication processes. The challenging aspects of the mechanical design and several of the more difficult production processes are discussed. In addition, the successes, failures, and lessons learned from acoustic and random vibration testing of a full-scale prototype instrument are presented.

Enhanced Deposition by Electrostatic Field-Assistance Aggravating Diesel Exhaust Aerosol Toxicity for Human Lung Cells.

PubMed

Stoehr, Linda C; Madl, Pierre; Boyles, Matthew S P; Zauner, Roland; Wimmer, Monika; Wiegand, Harald; Andosch, Ancuela; Kasper, Gerhard; Pesch, Markus; Lütz-Meindl, Ursula; Himly, Martin; Duschl, Albert

2015-07-21

Air pollution is associated with increased risk of cardiovascular and pulmonary diseases, but conventional air quality monitoring gives no information about biological consequences. Exposing human lung cells at the air-liquid interface (ALI) to ambient aerosol could help identify acute biological responses. This study investigated electrode-assisted deposition of diesel exhaust aerosol (DEA) on human lung epithelial cells (A549) in a prototype exposure chamber. A549 cells were exposed to DEA at the ALI and under submerged conditions in different electrostatic fields (EFs) and were assessed for cell viability, membrane integrity, and IL-8 secretion. Qualitative differences of the DEA and its deposition under different EFs were characterized using scanning mobility particle sizer (SMPS) measurements, transmission electron microscopy (TEM), and electron energy loss spectroscopy (EELS). Upon exposure to DEA only, cell viability decreased and membrane impairment increased for cells at the ALI; submerged cells were unaffected. These responses were enhanced upon application of an EF, as was DEA deposition. No adverse effects were observed for filtered DEA or air only, confirming particle-induced responses. The prototype exposure chamber proved suitable for testing DEA-induced biological responses of cells at the ALI using electrode-assisted deposition and may be useful for analysis of other air pollutants.

Evaluation of Noncontact Power Collection Techniques

DOT National Transportation Integrated Search

1972-07-01

An evaluation is made of four basic noncontacting techniques of power collection which have possible applicability in future high speed ground transportation systems. The techniques considered include the electric arc, magnetic induction, electrostat...

Environmentally friendly power generator based on moving liquid dielectric and double layer effect.

PubMed

Huynh, D H; Nguyen, T C; Nguyen, P D; Abeyrathne, C D; Hossain, Md S; Evans, R; Skafidas, E

2016-06-03

An electrostatic power generator converts mechanical energy to electrical energy by utilising the principle of variable capacitance. This change in capacitance is usually achieved by varying the gap or overlap between two parallel metallic plates. This paper proposes a novel electrostatic micro power generator where the change in capacitance is achieved by the movement of an aqueous solution of NaCl. A significant change in capacitance is achieved due to the higher than air dielectric constant of water and the Helmholtz double layer capacitor formed by ion separation at the electrode interfaces. The proposed device has significant advantages over traditional electrostatic devices which include low bias voltage and low mechanical frequency of operation. This is critical if the proposed device is to have utility in harvesting power from the environment. A figure of merit exceeding 10000(10(8)μW)/(mm(2)HzV(2)) which is two orders of magnitude greater than previous devices, is demonstrated for a prototype operating at a bias voltage of 1.2 V and a droplet frequency of 6 Hz. Concepts are presented for large scale power harvesting.

Aeroelastic flutter energy harvesters self-polarized by triboelectric effects

NASA Astrophysics Data System (ADS)

Perez, M.; Boisseau, S.; Geisler, M.; Gasnier, P.; Willemin, J.; Despesse, G.; Reboud, J. L.

2018-01-01

This paper presents the performances of several electrostatic flutter energy harvesters tested in a wind tunnel between 0 and 20 m s-1. The main idea is to use the flutter capability of thin flexible films confined between lateral walls to induce simultaneously the capacitance variations and the electrostatic polarization required by the triboelectric/electrostatic conversion. This technology provides thin and flexible devices and solve the electret’s stability issue (Perez et al 2015 Smart Mater. Struct., Perez et al 2015 New Circuits and Systems). Our prototypes (<16 cm2) have a quick startup (from 3 m s-1) and an electrical power-flux density from 0.35 μW cm-2@3 m s-1 (light breeze) to 35 μW cm-2@20 m s-1 (fresh gale). A Maximum Power Point circuit has been developed to efficiently use the power provided by the energy harvesters. The energy harvester combined with its power management circuit has finally been used to supply an 868 MHz wireless sensor node with temperature and acceleration measurements, validating the complete energy harvesting chain.

Development of a negative ion-based neutral beam injector in Novosibirsk.

PubMed

Ivanov, A A; Abdrashitov, G F; Anashin, V V; Belchenko, Yu I; Burdakov, A V; Davydenko, V I; Deichuli, P P; Dimov, G I; Dranichnikov, A N; Kapitonov, V A; Kolmogorov, V V; Kondakov, A A; Sanin, A L; Shikhovtsev, I V; Stupishin, N V; Sorokin, A V; Popov, S S; Tiunov, M A; Belov, V P; Gorbovsky, A I; Kobets, V V; Binderbauer, M; Putvinski, S; Smirnov, A; Sevier, L

2014-02-01

A 1000 keV, 5 MW, 1000 s neutral beam injector based on negative ions is being developed in the Budker Institute of Nuclear Physics, Novosibirsk in collaboration with Tri Alpha Energy, Inc. The innovative design of the injector features the spatially separated ion source and an electrostatic accelerator. Plasma or photon neutralizer and energy recuperation of the remaining ion species is employed in the injector to provide an overall energy efficiency of the system as high as 80%. A test stand for the beam acceleration is now under construction. A prototype of the negative ion beam source has been fabricated and installed at the test stand. The prototype ion source is designed to produce 120 keV, 1.5 A beam.

Investigation of Electrostatic Charge in Hose Lines

DTIC Science & Technology

2006-10-01

of the system. A INSULATORINSULATOR Ir1 Q Q dH vH A INSULATORINSULATOR Ir2 Q dm dl 2 vm LmLH S1 S2 S3EXTERNAL WIRE BRAID ON HOSE vl 2vm dm Lm dl...sizes of fuel hoses , including hoses with and without integrally bonded grounding wire braid ; (4) Different lengths of hose test sections; (5...Different earth grounding contact conditions along the hose test section, such as: (i) Complete insulation from the ground; (ii) Wire braid conductor along

The Effects of Thunderstorm Static and Quasi-Static Electric Fields on the Lower Ionosphere

NASA Astrophysics Data System (ADS)

Salem, Mohammad Ahmad

Thunderstorms and their lightning discharges are of great interest to many areas of geophysics and atmospheric electricity. A thunderstorm is an electric generator; it can produce both electrostatic and quasi-electrostatic fields in the overhead atmospheric D region. The D region is the lower part of the ionosphere that extends from about 40-90 km altitude where the electrons and ions are sufficient enough to affect the propagation of radio waves. In contrast to the electrostatic field, the quasi-electrostatic fields can be much stronger in magnitude, but shorter in duration, and can trigger halos. A halo is one type of the transient luminous events (TLEs) and typically appears within 1-2 ms after an intense cloud to ground lightning discharge. It looks like a relatively homogeneous glow in the shape of a pancake that is centered around 75-80 km altitude with a horizontal extent of tens of kilometers and vertical thickness of several kilometers. The goals of this dissertation research are to investigate the electrical effects of thunderstorm electrostatic and quasi-electrostatic fields on the nighttime lower ionosphere, and their covert relation to the formation of atmospheric halos. This work entails numerical and theoretical modeling analyses, and comparison of current theory and simulation results with the actual observations. For the first part of this study we have demonstrated that, under steady state conditions, electrostatic fields of <0.4Ek values (not strong enough to produce TLEs) can be established in the lower ionosphere due to underlying thunderstorms. We utilized the simplified nighttime ion chemistry model described in the work of Liu [2012] to investigate how these fields affect the lower ionosphere ion density profile. The three-body electron attachment, through which electrons can be converted to negative ions, is the only process whose rate constant depends on the field values within the above-mentioned limit. As a result of the variation of the rate constant with the electric field, the nighttime steady state electron density profile can be reduced by ˜40% or enhanced by a factor of ˜6. We have improved our model in order to self-consistently calculate the steady state conductivity of the lower ionosphere above a thunderstorm. The new model takes into account the heating effects of thunderstorm electrostatic fields on the free electrons. The modeling results indicate that under steady state condition, although the electron density is generally increased, the nighttime lower ionospheric conductivity can be reduced by up to 1-2 orders of magnitude because electron mobility is significantly reduced due to the electron heating effect. Because of this reduction, it is found that for a typical ionospheric density profile, the resulting changes in the reflection heights of ELF and VLF waves are 5 and 2 km, respectively. In the second part of this dissertation, a one-dimensional plasma discharge fluid model is developed to study the response of the nighttime lower ionosphere to the quasi-electrostatic field produced by cloud-to-ground lightning flashes. When the quasi-electrostatic field reaches and exceeds about E k, a halo can be triggered in the lower ionosphere. The modeling results indicate that the ionospheric perturbation is determined by the ambient ionospheric density profile, the charge. moment change, and charge transfer time. Tenuous ambient profiles result in larger changes in the ionospheric electron density. Cloud-to-ground lightning discharges, with larger charge moment changes and shorter charge transfer times, result in a larger change in the ionospheric electron density. In particular, the enhancement in the lower ionospheric electron density due to impulsive negative cloud-to-ground lightning flashes has been investigated. It is found that the enhancement can reach up to about 3 orders of magnitude above ˜70 km altitude in a few seconds. Below ˜75 km altitude, this enhancement recovers in a few seconds due to the fast electron attachment process. The recovery time of the electron enhancement above ˜75 km altitude is controlled by a slower recombination process; it depends on the ambient density profile and can last for tens of minutes to hours. Finally, the modeling results of the lower ionosphere recovery time are analyzed to investigate the role of halos in producing early VLF events with long recovery time. It is found that these events can be explained when sufficient ionization is produced around ˜80 km altitude. Such ionization can be produced by the impact of impulsive negative cloud-to-ground lightning flashes with a relatively large charge moment change on a tenuous ionospheric density profile.

New high-resolution electrostatic ion mass analyzer using time of flight

NASA Technical Reports Server (NTRS)

Hamilton, D. C.; Gloeckler, G.; Ipavich, F. M.; Lundgren, R. A.; Sheldon, R. B.

1990-01-01

The design of a high-resolution ion-mass analyzer is described, which is based on an accurate measurement of the time of flight (TOF) of ions within a region configured to produce a harmonic potential. In this device, the TOF, which is independent of ion energy, is determined from a start pulse from secondary electrons produced when the ion passes through a thin carbon foil at the entrance of the TOF region and at a stop pulse from the ion striking a microchannel plate upon exciting the region. A laboratory prototype instrument called 'VMASS' was built and was tested at the Goddard Space Flight Center electrostatic accelerator, showing a good mass resolution of the instrument. Sensors of the VMASS type will form part of the WIND Solar Wind and Suprathermal Ion experiment, the Soho mission, and the Advanced Composition Explorer.

An electrostatic 3-phase linear stepper motor fabricated by vertical trench isolation technology

NASA Astrophysics Data System (ADS)

Sarajlic, Edin; Yamahata, Christophe; Cordero, Mauricio; Fujita, Hiroyuki

2009-07-01

We present the design, microfabrication and characterization of an electrostatic 3-phase linear stepper micromotor constructed with vertical trench isolation technology. This suitable technology was used to create a monolithic stepper motor with high-aspect-ratio poles and an integrated 3-phase electrical network in the bulk of a standard single-crystal silicon wafer. The shuttle of the stepper motor is suspended by a flexure to avoid any mechanical contact during operation, enhancing the precision, repeatability and reliability of the stepping motion. The prototype is capable of a maximum travel of +/-26 µm (52 µm) at an actuation voltage of 30 V and a step size of 1.4 µm during a half-stepping sequence. This work was presented in part at the 19th MicroMechanics Europe Workshop (MME), 28-30 September 2008, Aachen, Germany.

On-irrigator pasture soil moisture sensor

NASA Astrophysics Data System (ADS)

Eng-Choon Tan, Adrian; Richards, Sean; Platt, Ian; Woodhead, Ian

2017-02-01

In this paper, we presented the development of a proximal soil moisture sensor that measured the soil moisture content of dairy pasture directly from the boom of an irrigator. The proposed sensor was capable of soil moisture measurements at an accuracy of  ±5% volumetric moisture content, and at meter scale ground area resolutions. The sensor adopted techniques from the ultra-wideband radar to enable measurements of ground reflection at resolutions that are smaller than the antenna beamwidth of the sensor. An experimental prototype was developed for field measurements. Extensive field measurements using the developed prototype were conducted on grass pasture at different ground conditions to validate the accuracy of the sensor in performing soil moisture measurements.

Manufacturing Methods and Technology Project Summary Reports

DTIC Science & Technology

1986-07-01

Yuma Proving Ground in January 1985. The ARBAT system provides a unique real-time computer capability to identify all critical flight...cheaper tnaii the existing radar system. This prototype is expected to save over ^1 million per year at Yuma Proving Grounds . TECOM is planning to...purchase 4 production ballistic radar systems to be installed at Yuma Proving Grounds , Dugway Proving Grounds , and Jefferson Proving Grounds at a

Contribution of crosstalk to the uncertainty of electrostatic actuator calibrations.

PubMed

Shams, Qamar A; Soto, Hector L; Zuckerwar, Allan J

2009-09-01

Crosstalk in electrostatic actuator calibrations is defined as the ratio of the microphone response to the actuator excitation voltage at a given frequency with the actuator polarization voltage turned off to the response, at the excitation frequency, with the polarization voltage turned on. It consequently contributes to the uncertainty of electrostatic actuator calibrations. Two sources of crosstalk are analyzed: the first attributed to the stray capacitance between the actuator electrode and the microphone backplate, and the second to the ground resistance appearing as a common element in the actuator excitation and microphone input loops. Measurements conducted on 1/4, 1/2, and 1 in. air condenser microphones reveal that the crosstalk has no frequency dependence up to the membrane resonance frequency and that the level of crosstalk lies at about -60 dB for all three microphones-conclusions that are consistent with theory. The measurements support the stray capacitance model. The contribution of crosstalk to the measurement standard uncertainty of an electrostatic actuator calibration is therewith 0.01 dB.

Electrostatic antenna space environment interaction study

NASA Technical Reports Server (NTRS)

Katz, I.

1981-01-01

The interactions of the electrostatic antenna with the space environment in both low Earth orbit and geosynchronous orbit are investigated. It is concluded that the electrostatically controlled membrane mirror is a viable concept for space applications. However, great care must be taken to enclose the high voltage electrodes in a Faraday cage structure to separate the high voltage region from the ambient plasma. For this reason, metallized cloth is not acceptable as a membrane material. Conventional spacecraft charging at geosynchronous orbit should not be a problem provided ancillary structures (such as booms) are given nonnegligible conductivity and adequate grounding. Power loss due to plasma electrons entering the high field region is a potentially serious problem. In low earth orbit any opening whatever in the Faraday cage is likely to produce an unacceptable power drain.

Demonstrating a Realistic IP Mission Prototype

NASA Technical Reports Server (NTRS)

Rash, James; Ferrer, Arturo B.; Goodman, Nancy; Ghazi-Tehrani, Samira; Polk, Joe; Johnson, Lorin; Menke, Greg; Miller, Bill; Criscuolo, Ed; Hogie, Keith

2003-01-01

Flight software and hardware and realistic space communications environments were elements of recent demonstrations of the Internet Protocol (IP) mission concept in the lab. The Operating Missions as Nodes on the Internet (OMNI) Project and the Flight Software Branch at NASA/GSFC collaborated to build the prototype of a representative space mission that employed unmodified off-the-shelf Internet protocols and technologies for end-to-end communications between the spacecraft/instruments and the ground system/users. The realistic elements used in the prototype included an RF communications link simulator and components of the TRIANA mission flight software and ground support system. A web-enabled camera connected to the spacecraft computer via an Ethernet LAN represented an on-board instrument creating image data. In addition to the protocols at the link layer (HDLC), transport layer (UDP, TCP), and network (IP) layer, a reliable file delivery protocol (MDP) at the application layer enabled reliable data delivery both to and from the spacecraft. The standard Network Time Protocol (NTP) performed on-board clock synchronization with a ground time standard. The demonstrations of the prototype mission illustrated some of the advantages of using Internet standards and technologies for space missions, but also helped identify issues that must be addressed. These issues include applicability to embedded real-time systems on flight-qualified hardware, range of applicability of TCP, and liability for and maintenance of commercial off-the-shelf (COTS) products. The NASA Earth Science Technology Office (ESTO) funded the collaboration to build and demonstrate the prototype IP mission.

Rapid Prototyping in PVS

NASA Technical Reports Server (NTRS)

Munoz, Cesar A.; Butler, Ricky (Technical Monitor)

2003-01-01

PVSio is a conservative extension to the PVS prelude library that provides basic input/output capabilities to the PVS ground evaluator. It supports rapid prototyping in PVS by enhancing the specification language with built-in constructs for string manipulation, floating point arithmetic, and input/output operations.

Second Breakdown of 18V Grounded Gate NMOS induced by the Kirk Effect under Electrostatic Discharge

NASA Astrophysics Data System (ADS)

Jeon, Byung-Chul; Lee, Seung-Chul; Han, Min-Koo

2003-09-01

Electrostatic Discharge (ESD) failure mechanisms of 18V grounded gate NMOS (GGNMOS) for liquid crystal display driver IC (LDI) applications are investigated and effects of layout design parameters on the ESD immunity level are analyzed. Experimental results show that 18V GGNMOS exhibits snapback characteristics and the ESD immunity level is rather high when XO (N-drift overlap over n+ source/drain) is sufficiently large, while GGNMOS does not exhibit the sustaining region and is very vulnerable to ESD stress when XO is relatively small. Simulation results show that the ESD failure mechanism of 18V GGNMOS could be the low-temperature second breakdown induced by the Kirk effect. It is inferred that a certain amount of XO is indispensable to ensure snapback characteristics and high ESD immunity level. Simulation results also show that the ESD immunity level is increased as drain contact to gate space (DCGS) is increased.

Structural and phylogenetic analysis of Rhodobacter capsulatus NifF: uncovering general features of nitrogen-fixation (nif)-flavodoxins.

PubMed

Pérez-Dorado, Inmaculada; Bortolotti, Ana; Cortez, Néstor; Hermoso, Juan A

2013-01-09

Analysis of the crystal structure of NifF from Rhodobacter capsulatus and its homologues reported so far reflects the existence of unique structural features in nif flavodoxins: a leucine at the re face of the isoalloxazine, an eight-residue insertion at the C-terminus of the 50's loop and a remarkable difference in the electrostatic potential surface with respect to non-nif flavodoxins. A phylogenetic study on 64 sequences from 52 bacterial species revealed four clusters, including different functional prototypes, correlating the previously defined as "short-chain" with the firmicutes flavodoxins and the "long-chain" with gram-negative species. The comparison of Rhodobacter NifF structure with other bacterial flavodoxin prototypes discloses the concurrence of specific features of these functional electron donors to nitrogenase.

Multipolar electrostatics.

PubMed

Cardamone, Salvatore; Hughes, Timothy J; Popelier, Paul L A

2014-06-14

Atomistic simulation of chemical systems is currently limited by the elementary description of electrostatics that atomic point-charges offer. Unfortunately, a model of one point-charge for each atom fails to capture the anisotropic nature of electronic features such as lone pairs or π-systems. Higher order electrostatic terms, such as those offered by a multipole moment expansion, naturally recover these important electronic features. The question remains as to why such a description has not yet been widely adopted by popular molecular mechanics force fields. There are two widely-held misconceptions about the more rigorous formalism of multipolar electrostatics: (1) Accuracy: the implementation of multipole moments, compared to point-charges, offers little to no advantage in terms of an accurate representation of a system's energetics, structure and dynamics. (2) Efficiency: atomistic simulation using multipole moments is computationally prohibitive compared to simulation using point-charges. Whilst the second of these may have found some basis when computational power was a limiting factor, the first has no theoretical grounding. In the current work, we disprove the two statements above and systematically demonstrate that multipole moments are not discredited by either. We hope that this perspective will help in catalysing the transition to more realistic electrostatic modelling, to be adopted by popular molecular simulation software.

Near-infrared Compressive Line Sensing Imaging System using Individually Addressable Laser Diode Array

DTIC Science & Technology

2015-05-11

Micromirror Device (DMD) is a microelectromechanical (MEMS) device. A DMD consists of millions of electrostatically actuated micro- mirrors (or pixels...digital micromirror device) were analyzed. We discussed the effort of developing such a prototype by Proc. of SPIE Vol. 9484 94840I-11 Downloaded...to Digital Micromirror Device (DMD) Technology”, (n.d.) Retrieved May 1, 2011, from http://www.ti.com/lit/an/dlpa008a/dlpa008a.pdf. [16

Development of a novel translation micromirror for adaptive optics

NASA Astrophysics Data System (ADS)

He, Siyuan; Ben Mrad, Ridha

2003-10-01

Conventional translation micromirrors for adaptive optics use attractive electrostatic force and therefore have two limitations: 1) the stroke is limited to less than one third of the initial gap distance between the mirror plate and the substrate. Normally the stroke is in the range of submicrometers; 2) stiction happens during operation. A novel translation micromirror, which uses a repulsive electrostatic force, is presented in this paper. This novel translation micromirror completely overcomes the limitations associated with conventional translation micromirrors and its stroke is not limited by the initial gap distance between the mirror plate and the substrate and therefore is able to achieve a much larger vertical stroke to modulate lights over a wider spectrum than that achieved by conventional translation micromirrors. The novel translation micromirror has no stiction problem and is highly compatible with mature surface micromachining technology. An analytical model is derived for the novel translation micromirror and prototypes are fabricated. The prototype of the novel translation micromirror, which is deliberately not optimized so it could be fabricated using MUMPS, achieved a vertical stroke of 1.75μm using a driving voltage of 50 volts, which is three times the stroke of conventional MUMPS translation micromirrors. It is expected that if standard surface micromachining is used instead of MUMPs, the design of the novel translation micromirror can be optimized and a much larger vertical stroke can be achieved.

Evaluating a filtering and recirculating system to reduce dust drift in simulated sowing of dressed seed and abraded dust particle characteristics.

PubMed

Biocca, Marcello; Pochi, Daniele; Fanigliulo, Roberto; Gallo, Pietro; Pulcini, Patrizio; Marcovecchio, Francesca; Perrino, Cinzia

2017-06-01

The pneumatic precision drills used in maize sowing can release dust owing to abrasion of dressed seed; the drift of dust containing insecticide active ingredients is harmful to honey bees. Therefore, we developed a device for drills that uses partial recirculation and filtration of the air by means of an antipollen and an electrostatic filter. Tests were carried out by simulating the sowing of seed treated with imidacloprid, thiamethoxam, clothianidin and fipronil. Dust released by the drill in different configurations was analysed to assess its mass and active ingredient concentration, size distribution and particle number concentration. In general, particles with a diameter smaller than 2.5 and 10 µm represent about 40 and 75% of the total dust mass respectively. The finest size fraction (<1 µm) contains a higher content of active ingredient. The prototype equipped with both antipollen and electrostatic filters always showed a reduction in dust emission greater than 90% in terms of both total mass and active ingredient amount, with a greater efficiency in the reduction in particles below 4 µm. This study presents an engineering solution addressing dust losses during sowing, contributes to the description of abrasion dust fractions and provides suggestions for further development of the prototype. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Passive radon/thoron personal dosimeter using an electrostatic collector and a diffused-junction detector

NASA Astrophysics Data System (ADS)

Bigu, J.; Raz, R.

1985-01-01

A solid-state alpha dosimeter has been designed and tested suitable for personal and environmental radon/thoron monitoring. The dosimeter basically consists of an electrostatic collector and an alpha-particle counting system with spectroscopy capabilities. The sensitive volume (˜20 cm3) of the electrostatic collector consists of a cylindrically shaped metal wire screen and a diffused-junction silicon alpha-detector covered with a thin aluminized Mylar sheet. A dc voltage (˜500 V) is applied between the wire screen and the Mylar sheet, with the latter held at negative potential relative to the former. Data can be retrieved during or after sampling by means of a microcomputer (Epson HX20) via a RS-232 communication interface unit. The dosimeter has been calibrated in a large (26 m3) radon/thoron test facility. A linear relationship was found between the dosimeter's alpha-count and both radon gas concentration and radon daughter working level. The dosimeter is mounted on top of an ordinary miner's cap lamp battery and is ideally suited for personal monitoring in underground uranium mines and other working areas. The dosimeter presented here is a considerably improved version of an earlier prototype.

Environmentally friendly power generator based on moving liquid dielectric and double layer effect

PubMed Central

Huynh, D. H.; Nguyen, T. C.; Nguyen, P. D.; Abeyrathne, C. D.; Hossain, Md. S.; Evans, R.; Skafidas, E.

2016-01-01

An electrostatic power generator converts mechanical energy to electrical energy by utilising the principle of variable capacitance. This change in capacitance is usually achieved by varying the gap or overlap between two parallel metallic plates. This paper proposes a novel electrostatic micro power generator where the change in capacitance is achieved by the movement of an aqueous solution of NaCl. A significant change in capacitance is achieved due to the higher than air dielectric constant of water and the Helmholtz double layer capacitor formed by ion separation at the electrode interfaces. The proposed device has significant advantages over traditional electrostatic devices which include low bias voltage and low mechanical frequency of operation. This is critical if the proposed device is to have utility in harvesting power from the environment. A figure of merit exceeding 10000(108μW)/(mm2HzV2) which is two orders of magnitude greater than previous devices, is demonstrated for a prototype operating at a bias voltage of 1.2 V and a droplet frequency of 6 Hz. Concepts are presented for large scale power harvesting. PMID:27255577

Probing size-dependent electrokinetics of hematite aggregates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kedra-Królik, Karolina; Rosso, Kevin M.; Zarzycki, Piotr

Aqueous particle suspensions of many kinds are stabilized by the electrostatic potential developed at their surfaces from reaction with water and ions. An important and less well understood aspect of this stabilization is the dependence of the electrostatic surface potential on particle size. Surface electrostatics are typically probed by measuring particle electrophoretic mobilities and quantified in the electrokinetic potential (f), using commercially available Zeta Potential Analyzers (ZPA). Even though ZPAs provide frequency-spectra (histograms) of electrophoretic mobility and hydrodynamic diameter, typically only the maximal-intensity values are reported, despite the information in the remainder of the spectra. Here we propose a mappingmore » procedure that inter-correlates these histograms to extract additional insight, in this case to probe particle size-dependent electrokinetics. Our method is illustrated for a suspension of prototypical iron (III) oxide (hematite, a-Fe2O3). We found that the electrophoretic mobility and f-potential are a linear function of the aggregate size. By analyzing the distribution of surface site types as a function of aggregate size we show that site coordination increases with increasing aggregate diameter. This observation explains why the acidity of the iron oxide particles decreases with increasing particle size.« less

ED01-0146-1

NASA Image and Video Library

2001-04-28

Ground crewmen maneuver AeroVironment's solar-powered Helios Prototype flying wing on its ground support dolly during functional checkouts prior to its first flights under solar power from the U.S. Navy's Pacific Missile Range Facility on Kaua'i, Hawaii.

ED01-0146-6

NASA Image and Video Library

2001-04-28

Ground crewmen maneuver AeroVironment's solar-powered Helios Prototype flying wing on its ground support dolly during functional checkouts prior to its first flights under solar power from the U.S. Navy's Pacific Missile Range Facility on Kaua'i, Hawaii.

ED01-0146-5

NASA Image and Video Library

2001-04-28

Ground crewmen maneuver AeroVironment's solar-powered Helios Prototype flying wing on its ground support dolly during functional checkouts prior to its first flights under solar power from the U.S. Navy's Pacific Missile Range Facility on Kaua'i, Hawaii.

ED01-0146-2

NASA Image and Video Library

2001-04-28

Ground crewmen maneuver AeroVironment's solar-powered Helios Prototype flying wing on its ground support dolly during functional checkouts prior to its first flights under solar power from the U.S. Navy's Pacific Missile Range Facility on Kaua'i, Hawaii.

IEC fusion: The future power and propulsion system for space

NASA Astrophysics Data System (ADS)

Hammond, Walter E.; Coventry, Matt; Hanson, John; Hrbud, Ivana; Miley, George H.; Nadler, Jon

2000-01-01

Rapid access to any point in the solar system requires advanced propulsion concepts that will provide extremely high specific impulse, low specific power, and a high thrust-to-power ratio. Inertial Electrostatic Confinement (IEC) fusion is one of many exciting concepts emerging through propulsion and power research in laboratories across the nation which will determine the future direction of space exploration. This is part of a series of papers that discuss different applications of the Inertial Electrostatic Confinement (IEC) fusion concept for both in-space and terrestrial use. IEC will enable tremendous advances in faster travel times within the solar system. The technology is currently under investigation for proof of concept and transitioning into the first prototype units for commercial applications. In addition to use in propulsion for space applications, terrestrial applications include desalinization plants, high energy neutron sources for radioisotope generation, high flux sources for medical applications, proton sources for specialized medical applications, and tritium production. .

Status of Electrostatic Accelerometer Development for Gravity Recovery and Climate Experiment Follow-On Mission (GRACE FO)

NASA Astrophysics Data System (ADS)

Perrot, Eddy; Boulanger, Damien; Christophe, Bruno; Foulon, Bernard; Liorzou, Françoise; Lebat, Vincent; Huynh, Phuong-Anh

2015-04-01

The GRACE FO mission, led by the JPL (Jet Propulsion Laboratory), is an Earth-orbiting gravity mission, continuation of the GRACE mission, which will produce an accurate model of the Earth's gravity field variation providing global climatic data during five years at least. The mission involves two satellites in a loosely controlled tandem formation, with a micro-wave link measuring the inter-satellites distance variation. Earth's mass distribution non-uniformities cause variations of the inter-satellite distance. This variation is measured to recover gravity, after subtracting the non-gravitational contributors, as the residual drag. ONERA (the French Aerospace Lab) is developing, manufacturing and testing electrostatic accelerometers measuring this residual drag applied on the satellites. The accelerometer is composed of two main parts: the Sensor Unit (including the Sensor Unit Mechanics - SUM - and the Front-End Electronic Unit - FEEU) and the Interface Control Unit - ICU. In the Accelerometer Core, located in the Sensor Unit Mechanics, the proof mass is levitated and maintained at the center of an electrode cage by electrostatic forces. Thus, any drag acceleration applied on the satellite involves a variation on the servo-controlled electrostatic suspension of the mass. The voltage on the electrodes providing this electrostatic force is the measurement output of the accelerometer. The impact of the accelerometer defaults (geometry, electronic and parasitic forces) leads to bias, misalignment and scale factor error, non-linearity and noise. Some of these accelerometer defaults are characterized by tests with micro-gravity pendulum bench on ground and with drops in ZARM catapult. The Critical Design Review was achieved successfully on September 2014. The Engineering Model (EM) was integrated and tested successfully, with ground levitation, drops, Electromagnetic Compatibility and thermal vacuum. The integration of the first Flight Model has begun on December 2014 and will be achieved on January 2015. The results of the Engineering Model tests and the status of the Flight Models will be presented.

Tests Results of the Electrostatic Accelerometer Flight Models for Gravity Recovery and Climate Experiment Follow-On Mission (GRACE FO)

NASA Astrophysics Data System (ADS)

Perrot, E.; Boulanger, D.; Christophe, B.; Foulon, B.; Lebat, V.; Huynh, P. A.; Liorzou, F.

2015-12-01

The GRACE FO mission, led by the JPL (Jet Propulsion Laboratory), is an Earth-orbiting gravity mission, continuation of the GRACE mission, which will produce an accurate model of the Earth's gravity field variation providing global climatic data during five years at least. The mission involves two satellites in a loosely controlled tandem formation, with a micro-wave link measuring the inter-satellites distance variation. Earth's mass distribution non-uniformities cause variations of the inter-satellite distance. This variation is measured to recover gravity, after subtracting the non-gravitational contributors, as the residual drag. ONERA (the French Aerospace Lab) is developing, manufacturing and testing electrostatic accelerometers measuring this residual drag applied on the satellites. The accelerometer is composed of two main parts: the Sensor Unit (including the Sensor Unit Mechanics - SUM - and the Front-End Electronic Unit - FEEU) and the Interface Control Unit - ICU. In the Accelerometer Core, located in the Sensor Unit Mechanics, the proof mass is levitated and maintained at the center of an electrode cage by electrostatic forces. Thus, any drag acceleration applied on the satellite involves a variation on the servo-controlled electrostatic suspension of the mass. The voltage on the electrodes providing this electrostatic force is the output measurement of the accelerometer. The impact of the accelerometer defaults (geometry, electronic and parasitic forces) leads to bias, misalignment and scale factor error, non-linearity and noise. Some of these accelerometer defaults are characterized by tests with micro-gravity pendulum bench on ground and with drops in ZARM catapult. The Critical Design Review was achieved successfully on September 2014. The Engineering Model (EM) was integrated and tested successfully, with ground levitation, drops, Electromagnetic Compatibility and thermal vacuum. The integration of the two Flight Models was done on July 2015. The tests will be achieved from July to November 2015. The results of the Engineering Model and Flight Models tests will be presented.

On the ground state energy of the δ-function Bose gas

NASA Astrophysics Data System (ADS)

Tracy, Craig A.; Widom, Harold

2016-07-01

The weak coupling asymptotics, to order {(c/ρ )}2, of the ground state energy of the delta-function Bose gas is derived. Here 2c≥slant 0 is the delta-function potential amplitude and ρ the density of the gas in the thermodynamic limit. The analysis uses the electrostatic interpretation of the Lieb-Liniger integral equation. Dedicated to Professor Tony Guttmann on the occasion of his 70th birthday.

A rapid boundary integral equation technique for protein electrostatics

NASA Astrophysics Data System (ADS)

Grandison, Scott; Penfold, Robert; Vanden-Broeck, Jean-Marc

2007-06-01

A new boundary integral formulation is proposed for the solution of electrostatic field problems involving piecewise uniform dielectric continua. Direct Coulomb contributions to the total potential are treated exactly and Green's theorem is applied only to the residual reaction field generated by surface polarisation charge induced at dielectric boundaries. The implementation shows significantly improved numerical stability over alternative schemes involving the total field or its surface normal derivatives. Although strictly respecting the electrostatic boundary conditions, the partitioned scheme does introduce a jump artefact at the interface. Comparison against analytic results in canonical geometries, however, demonstrates that simple interpolation near the boundary is a cheap and effective way to circumvent this characteristic in typical applications. The new scheme is tested in a naive model to successfully predict the ground state orientation of biomolecular aggregates comprising the soybean storage protein, glycinin.

Electrostatic force microscopy on oriented graphite surfaces: coexistence of insulating and conducting behaviors.

PubMed

Lu, Yonghua; Muñoz, M; Steplecaru, C S; Hao, Cheng; Bai, Ming; Garcia, N; Schindler, K; Esquinazi, P

2006-08-18

We present measurements of the electric potential fluctuations on the surface of highly oriented pyrolytic graphite using electrostatic force and atomic force microscopy. Micrometric domainlike potential distributions are observed even when the sample is grounded. Such potential distributions are unexpected given the good metallic conductivity of graphite because the surface should be an equipotential. Our results indicate the coexistence of regions with "metalliclike" and "insulatinglike" behaviors showing large potential fluctuations of the order of 0.25 V. In lower quality graphite, this effect is not observed. Experiments are performed in Ar and air atmospheres.

Trapping of ultracold polar molecules with a thin-wire electrostatic trap.

PubMed

Kleinert, J; Haimberger, C; Zabawa, P J; Bigelow, N P

2007-10-05

We describe the realization of a dc electric-field trap for ultracold polar molecules, the thin-wire electrostatic trap (TWIST). The thin wires that form the electrodes of the TWIST allow us to superimpose the trap onto a magneto-optical trap (MOT). In our experiment, ultracold polar NaCs molecules in their electronic ground state are created in the MOT via photoassociation, achieving a continuous accumulation in the TWIST of molecules in low-field seeking states. Initial measurements show that the TWIST trap lifetime is limited only by the background pressure in the chamber.

Electromagnetic Compatibility for the Space Shuttle

NASA Technical Reports Server (NTRS)

Scully, Robert C.

2004-01-01

This slide presentation reviews the Space Shuttle electromagnetic compatibility (EMC). It includes an overview of the design of the shuttle with the areas that are of concern for the electromagnetic compatibility. It includes discussion of classical electromagnetic interference (EMI) and the work performed to control the electromagnetic interference. Another area of interest is electrostatic charging and the threat of electrostatic discharge and the attempts to reduce damage to the Shuttle from these possible hazards. The issue of electrical bonding is als reviewed. Lastly the presentation reviews the work performed to protect the shuttle from lightning, both in flight and on the ground.

Combining LaRC-TPI powder with carbon fiber by electrostatic fluidized bed coating

NASA Technical Reports Server (NTRS)

Varughese, Babu; Muzzy, John; Baucom, Robert M.

1989-01-01

Thermoplastic polyimide prepreg tow is produced rapidly and efficiently by applying the LaRC-TPI matrix as an electrostatically charged and fluidized powder to electrically grounded and spread carbon fiber tow. The powder is melted after coating to insure adhesion to the fibers and to reduce tow friction. Excellent wetout in towpreg samples is obtained resulting in very flexible prepregs. Processing conditions of this towpreg produced with LaRC-TPI powders from Rogers Corp. and Mitsui Toatsu Chemicals are described. Mechanical properties of the towpreg and unidirectional laminates are presented in detail.

Scheduling System Assessment, and Development and Enhancement of Re-engineered Version of GPSS

NASA Technical Reports Server (NTRS)

Loganantharaj, Rasiah; Thomas, Bushrod; Passonno, Nicole

1996-01-01

The objective of this project is two-fold. First to provide an evaluation of a commercially developed version of the ground processing scheduling system (GPSS) for its applicability to the Kennedy Space Center (KSC) ground processing problem. Second, to work with the KSC GPSS development team and provide enhancement to the existing software. Systems reengineering is required to provide a sustainable system for the users and the software maintenance group. Using the LISP profile prototype code developed by the GPSS reverse reengineering groups as a building block, we have implemented the resource deconfliction portion of GPSS in common LISP using its object oriented features. The prototype corrects and extends some of the deficiencies of the current production version, plus it uses and builds on the classes from the development team's profile prototype.

SP-100 GES/NAT radiation shielding systems design and development testing

NASA Astrophysics Data System (ADS)

Disney, Richard K.; Kulikowski, Henry D.; McGinnis, Cynthia A.; Reese, James C.; Thomas, Kevin; Wiltshire, Frank

1991-01-01

Advanced Energy Systems (AES) of Westinghouse Electric Corporation is under subcontract to the General Electric Company to supply nuclear radiation shielding components for the SP-100 Ground Engineering System (GES) Nuclear Assembly Test to be conducted at Westinghouse Hanford Company at Richland, Washington. The radiation shielding components are integral to the Nuclear Assembly Test (NAT) assembly and include prototypic and non-prototypic radiation shielding components which provide prototypic test conditions for the SP-100 reactor subsystem and reactor control subsystem components during the GES/NAT operations. W-AES is designing three radiation shield components for the NAT assembly; a prototypic Generic Flight System (GFS) shield, the Lower Internal Facility Shield (LIFS), and the Upper Internal Facility Shield (UIFS). This paper describes the design approach and development testing to support the design, fabrication, and assembly of these three shield components for use within the vacuum vessel of the GES/NAT. The GES/NAT shields must be designed to operate in a high vacuum which simulates space operations. The GFS shield and LIFS must provide prototypic radiation/thermal environments and mechanical interfaces for reactor system components. The NAT shields, in combination with the test facility shielding, must provide adequate radiation attenuation for overall test operations. Special design considerations account for the ground test facility effects on the prototypic GFS shield. Validation of the GFS shield design and performance will be based on detailed Monte Carlo analyses and developmental testing of design features. Full scale prototype testing of the shield subsystems is not planned.

CFD-ACE+: a CAD system for simulation and modeling of MEMS

NASA Astrophysics Data System (ADS)

Stout, Phillip J.; Yang, H. Q.; Dionne, Paul; Leonard, Andy; Tan, Zhiqiang; Przekwas, Andrzej J.; Krishnan, Anantha

1999-03-01

Computer aided design (CAD) systems are a key to designing and manufacturing MEMS with higher performance/reliability, reduced costs, shorter prototyping cycles and improved time- to-market. One such system is CFD-ACE+MEMS, a modeling and simulation environment for MEMS which includes grid generation, data visualization, graphical problem setup, and coupled fluidic, thermal, mechanical, electrostatic, and magnetic physical models. The fluid model is a 3D multi- block, structured/unstructured/hybrid, pressure-based, implicit Navier-Stokes code with capabilities for multi- component diffusion, multi-species transport, multi-step gas phase chemical reactions, surface reactions, and multi-media conjugate heat transfer. The thermal model solves the total enthalpy from of the energy equation. The energy equation includes unsteady, convective, conductive, species energy, viscous dissipation, work, and radiation terms. The electrostatic model solves Poisson's equation. Both the finite volume method and the boundary element method (BEM) are available for solving Poisson's equation. The BEM method is useful for unbounded problems. The magnetic model solves for the vector magnetic potential from Maxwell's equations including eddy currents but neglecting displacement currents. The mechanical model is a finite element stress/deformation solver which has been coupled to the flow, heat, electrostatic, and magnetic calculations to study flow, thermal electrostatically, and magnetically included deformations of structures. The mechanical or structural model can accommodate elastic and plastic materials, can handle large non-linear displacements, and can model isotropic and anisotropic materials. The thermal- mechanical coupling involves the solution of the steady state Navier equation with thermoelastic deformation. The electrostatic-mechanical coupling is a calculation of the pressure force due to surface charge on the mechanical structure. Results of CFD-ACE+MEMS modeling of MEMS such as cantilever beams, accelerometers, and comb drives are discussed.

From Vacuum Tubes to a Semiconductor Triode

NASA Astrophysics Data System (ADS)

Mil'shtein, S.

2005-06-01

Current study presents a brief review of an electronic technology evolution: from vacuum tubes, to transistors, to a novel, recently developed semiconductor triode, where electrons travel vertically about 600 angstroms from the filament to the anode. We plotted I-V and transfer curves for the semiconductor triodes. The very first prototypes proved to carry a maximum gain of about 15db and fT=8GHz. Filaments of variable length were produced to study mutual electrostatic interaction of the electrodes in the triode.

BIOPHYSICS. Comment on "Extreme electric fields power catalysis in the active site of ketosteroid isomerase".

PubMed

Chen, Deliang; Savidge, Tor

2015-08-28

Fried et al. (Reports, 19 December 2014, p. 1510) demonstrate electric field-dependent acceleration of biological catalysis using ketosteroid isomerase as a prototypic example. These findings were not extended to aqueous solution because water by itself has field fluctuations that are too large and fast to provide a catalytic effect. Given physiological context, when water electrostatic interactions are considered, electric fields play a less important role in the catalysis. Copyright © 2015, American Association for the Advancement of Science.

Prototype Environmental Assessment of the impacts of siting and construction of an SPS ground receiving station

NASA Technical Reports Server (NTRS)

Hill, J.

1980-01-01

A prototype assessment of the environmental impacts of siting and constructing a Satellite Power System (SPS) Ground Receiving Station (GRS) is reported. The objectives of the study were: (1) to develop an assessment of the nonmicrowave related impacts of the reference system SPS GRS on the natural environment; (2) to assess the impacts of GRS construction and operations in the context of actual baseline data for a site in the California desert; and (3) to identify critical GRS characteristics or parameters that are most significant in terms of the natural environment.

DNA-DNA interaction beyond the ground state

NASA Astrophysics Data System (ADS)

Lee, D. J.; Wynveen, A.; Kornyshev, A. A.

2004-11-01

The electrostatic interaction potential between DNA duplexes in solution is a basis for the statistical mechanics of columnar DNA assemblies. It may also play an important role in recombination of homologous genes. We develop a theory of this interaction that includes thermal torsional fluctuations of DNA using field-theoretical methods and Monte Carlo simulations. The theory extends and rationalizes the earlier suggested variational approach which was developed in the context of a ground state theory of interaction of nonhomologous duplexes. It shows that the heuristic variational theory is equivalent to the Hartree self-consistent field approximation. By comparison of the Hartree approximation with an exact solution based on the QM analogy of path integrals, as well as Monte Carlo simulations, we show that this easily analytically-tractable approximation works very well in most cases. Thermal fluctuations do not remove the ability of DNA molecules to attract each other at favorable azimuthal conformations, neither do they wash out the possibility of electrostatic “snap-shot” recognition of homologous sequences, considered earlier on the basis of ground state calculations. At short distances DNA molecules undergo a “torsional alignment transition,” which is first order for nonhomologous DNA and weaker order for homologous sequences.

Meeting Youth in Movement and on Neutral Ground

ERIC Educational Resources Information Center

Nissen, Morten

2015-01-01

The article articulates an educational motto--expressed in the title--found in a "prototypical narrative" of social youth work carried out by activists in Copenhagen in the 1990s. This way of modeling pedagogical practice is first outlined as different from the standardizing approach dominant in science. As a prototypical narrative, the…

Automated Platform Management System Scheduling

NASA Technical Reports Server (NTRS)

Hull, Larry G.

1990-01-01

The Platform Management System was established to coordinate the operation of platform systems and instruments. The management functions are split between ground and space components. Since platforms are to be out of contact with the ground more than the manned base, the on-board functions are required to be more autonomous than those of the manned base. Under this concept, automated replanning and rescheduling, including on-board real-time schedule maintenance and schedule repair, are required to effectively and efficiently meet Space Station Freedom mission goals. In a FY88 study, we developed several promising alternatives for automated platform planning and scheduling. We recommended both a specific alternative and a phased approach to automated platform resource scheduling. Our recommended alternative was based upon use of exactly the same scheduling engine in both ground and space components of the platform management system. Our phased approach recommendation was based upon evolutionary development of the platform. In the past year, we developed platform scheduler requirements and implemented a rapid prototype of a baseline platform scheduler. Presently we are rehosting this platform scheduler rapid prototype and integrating the scheduler prototype into two Goddard Space Flight Center testbeds, as the ground scheduler in the Scheduling Concepts, Architectures, and Networks Testbed and as the on-board scheduler in the Platform Management System Testbed. Using these testbeds, we will investigate rescheduling issues, evaluate operational performance and enhance the platform scheduler prototype to demonstrate our evolutionary approach to automated platform scheduling. The work described in this paper was performed prior to Space Station Freedom rephasing, transfer of platform responsibility to Code E, and other recently discussed changes. We neither speculate on these changes nor attempt to predict the impact of the final decisions. As a consequence some of our work and results may be outdated when this paper is published.

Electrostatically clean solar array

NASA Technical Reports Server (NTRS)

Stern, Theodore Garry (Inventor); Krumweide, Duane Eric (Inventor)

2004-01-01

Provided are methods of manufacturing an electrostatically clean solar array panel and the products resulting from the practice of these methods. The preferred method uses an array of solar cells, each with a coverglass where the method includes machining apertures into a flat, electrically conductive sheet so that each aperture is aligned with and undersized with respect to its matched coverglass sheet and thereby fashion a front side shield with apertures (FSA). The undersized portion about each aperture of the bottom side of the FSA shield is bonded to the topside portions nearest the edges of each aperture's matched coverglass. Edge clips are attached to the front side aperture shield edges with the edge clips electrically and mechanically connecting the tops of the coverglasses to the solar panel substrate. The FSA shield, edge clips and substrate edges are bonded so as to produce a conductively grounded electrostatically clean solar array panel.

Electrostatic interactions guide the active site face of a structure-specific ribonuclease to its RNA substrate.

PubMed

Plantinga, Matthew J; Korennykh, Alexei V; Piccirilli, Joseph A; Correll, Carl C

2008-08-26

Restrictocin, a member of the alpha-sarcin family of site-specific endoribonucleases, uses electrostatic interactions to bind to the ribosome and to RNA oligonucleotides, including the minimal specific substrate, the sarcin/ricin loop (SRL) of 23S-28S rRNA. Restrictocin binds to the SRL by forming a ground-state E:S complex that is stabilized predominantly by Coulomb interactions and depends on neither the sequence nor structure of the RNA, suggesting a nonspecific complex. The 22 cationic residues of restrictocin are dispersed throughout this protein surface, complicating a priori identification of a Coulomb interacting surface. Structural studies have identified an enzyme-substrate interface, which is expected to overlap with the electrostatic E:S interface. Here, we identified restrictocin residues that contribute to binding in the E:S complex by determining the salt dependence [partial differential log(k 2/ K 1/2)/ partial differential log[KCl

An electrostatic model for the determination of magnetic anisotropy in dysprosium complexes.

PubMed

Chilton, Nicholas F; Collison, David; McInnes, Eric J L; Winpenny, Richard E P; Soncini, Alessandro

2013-01-01

Understanding the anisotropic electronic structure of lanthanide complexes is important in areas as diverse as magnetic resonance imaging, luminescent cell labelling and quantum computing. Here we present an intuitive strategy based on a simple electrostatic method, capable of predicting the magnetic anisotropy of dysprosium(III) complexes, even in low symmetry. The strategy relies only on knowing the X-ray structure of the complex and the well-established observation that, in the absence of high symmetry, the ground state of dysprosium(III) is a doublet quantized along the anisotropy axis with an angular momentum quantum number mJ=±(15)/2. The magnetic anisotropy axis of 14 low-symmetry monometallic dysprosium(III) complexes computed via high-level ab initio calculations are very well reproduced by our electrostatic model. Furthermore, we show that the magnetic anisotropy is equally well predicted in a selection of low-symmetry polymetallic complexes.

Approximations useful for the prediction of electrostatic discharges for simple electrode geometries

NASA Technical Reports Server (NTRS)

Edmonds, L.

1986-01-01

The report provides approximations for estimating the capacitance and the ratio of electric field strength to potential for a certain class of electrode geometries. The geometry consists of an electrode near a grounded plane, with the electrode being a surface of revolution about the perpendicular to the plane. Some examples which show the accuracy of the capacitance estimate and the accuracy of the estimate of electric field over potential can be found in the appendix. When it is possible to estimate the potential of the electrode, knowing the ratio of electric field to potential will help to determine if an electrostatic discharge is likely to occur. Knowing the capacitance will help to determine the strength of the discharge (the energy released by it) if it does occur. A brief discussion of discharge mechanisms is given. The medium between the electrode and the grounded plane may be a neutral gas, a vacuum, or an unchanged homogeneous isotropic dielectric.

A new, simple electrostatic-acoustic hybrid levitator

NASA Technical Reports Server (NTRS)

Lierke, E. G.; Loeb, H.; Gross, D.

1990-01-01

Battelle has developed a hybrid levitator by combining the known single-axis acoustic standing wave levitator with a coaxial DC electric field. The resulting Coulomb forces on the charged liquid or solid sample support its weight and, together with the acoustic force, center the sample. Liquid samples with volumes approximately less than 100 micro-liters are deployed from a syringe reservoir into the acoustic pressure node. The sample is charged using a miniature high voltage power supply (approximately less than 20 kV) connected to the syringe needle. As the electric field, generated by a second miniature power supply, is increased, the acoustic intensity is reduced. The combination of both fields allows stable levitation of samples larger than either single technique could position on the ground. Decreasing the acoustic intensity reduces acoustic convection and sample deformation. Neither the electrostatic nor the acoustic field requires sample position sensing or active control. The levitator, now used for static and dynamic fluid physics investigations on the ground, can be easily modified for space operations.

On the Interpretation of the level structure of the Ground 3d5 Manifold of Mn III, Fe IV, Co V and Ni VI

NASA Astrophysics Data System (ADS)

Leushin, A. M.

2011-10-01

The level structure of the ground 3d5 configuration of Mn2+, Fe3+, Co4+ and Ni5+ ions was theoretically interpreted by means of a least-squares fit of the energy parameters to the observed values within the framework of the single-configuration approximation. In the Hamiltonian in addition to real electrostatic, spin-orbit, and spin-spin interactions, electrostatic and spin-orbit interactions correlated by configuration mixing were included. It was shown that the correct positions of almost all the energy levels are determined when the Hamiltonian includes the terms of the lineal (two-body operators) and nonlinear (three-body operators) theory of the configuration interaction. The most correct theoretical description of the experimental spectra was obtained by taking into account relativistic interactions and correlation effects of spin-orbit interactions. Adjustable parameters of the interactions included into the Hamiltonian were found.

Lightning energetics: Estimates of energy dissipation in channels, channel radii, and channel-heating risetimes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borovsky, J.E.

1998-05-01

In this report, several lightning-channel parameters are calculated with the aid of an electrodynamic model of lightning. The electrodynamic model describes dart leaders and return strokes as electromagnetic waves that are guided along conducting lightning channels. According to the model, electrostatic energy is delivered to the channel by a leader, where it is stored around the outside of the channel; subsequently, the return stroke dissipates this locally stored energy. In this report this lightning-energy-flow scenario is developed further. Then the energy dissipated per unit length in lightning channels is calculated, where this quantity is now related to the linear chargemore » density on the channel, not to the cloud-to-ground electrostatic potential difference. Energy conservation is then used to calculate the radii of lightning channels: their initial radii at the onset of return strokes and their final radii after the channels have pressure expanded. Finally, the risetimes for channel heating during return strokes are calculated by defining an energy-storage radius around the channel and by estimating the radial velocity of energy flow toward the channel during a return stroke. In three appendices, values for the linear charge densities on lightning channels are calculated, estimates of the total length of branch channels are obtained, and values for the cloud-to-ground electrostatic potential difference are estimated. {copyright} 1998 American Geophysical Union« less

SP-100 GES/NAT radiation shielding systems design and development testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Disney, R.K.; Kulikowski, H.D.; McGinnis, C.A.

1991-01-10

Advanced Energy Systems (AES) of Westinghouse Electric Corporation is under subcontract to the General Electric Company to supply nuclear radiation shielding components for the SP-100 Ground Engineering System (GES) Nuclear Assembly Test to be conducted at Westinghouse Hanford Company at Richland, Washington. The radiation shielding components are integral to the Nuclear Assembly Test (NAT) assembly and include prototypic and non-prototypic radiation shielding components which provide prototypic test conditions for the SP-100 reactor subsystem and reactor control subsystem components during the GES/NAT operations. W-AES is designing three radiation shield components for the NAT assembly; a prototypic Generic Flight System (GFS) shield,more » the Lower Internal Facility Shield (LIFS), and the Upper Internal Facility Shield (UIFS). This paper describes the design approach and development testing to support the design, fabrication, and assembly of these three shield components for use within the vacuum vessel of the GES/NAT. The GES/NAT shields must be designed to operate in a high vacuum which simulates space operations. The GFS shield and LIFS must provide prototypic radiation/thermal environments and mechanical interfaces for reactor system components. The NAT shields, in combination with the test facility shielding, must provide adequate radiation attenuation for overall test operations. Special design considerations account for the ground test facility effects on the prototypic GFS shield. Validation of the GFS shield design and performance will be based on detailed Monte Carlo analyses and developmental testing of design features. Full scale prototype testing of the shield subsystems is not planned.« less

Collecting Ground Samples for Balloon-Borne Instruments

NASA Technical Reports Server (NTRS)

Jones, Jack; Zimmerman, Wayne; Wu, Jiunn Jenq

2009-01-01

A proposed system in a gondola containing scientific instruments suspended by a balloon over the surface of the Saturn moon Titan would quickly acquire samples of rock or ice from the ground below. Prototypes of a sample-collecting device that would be a major part of the system have been tested under cryogenic and non-cryogenic conditions on Earth. Systems like this one could also be used in non-cryogenic environments on Earth to collect samples of rock, soil, ice, mud, or other ground material from such inaccessible or hazardous locations as sites of suspected chemical spills or biological contamination. The sample-collecting device would be a harpoonlike device that would be connected to the balloon-borne gondola by a tether long enough to reach the ground. The device would be dropped from the gondola to acquire a sample, then would be reeled back up to the gondola, where the sample would be analyzed by the onboard instruments. Each prototype of the sample-collecting device has a sharp front (lower) end, a hollow core for retaining a sample, a spring for holding the sample in the hollow core, and a rear (upper) annular cavity for retaining liquid sample material. Aerodynamic fins at the rear help to keep the front end pointed downward. In tests, these prototype devices were dropped from various heights and used to gather samples of dry sand, moist sand, cryogenic water ice, and warmer water ice.

Development of a Ground Test and Analysis Protocol to Support NASA's NextSTEP Phase 2 Habitation Concepts

NASA Technical Reports Server (NTRS)

Beaton, Kara H.; Chappell, Steven P.; Bekdash, Omar S.; Gernhardt, Michael L.

2018-01-01

The NASA Next Space Technologies for Exploration Partnerships (NextSTEP) program is a public-private partnership model that seeks commercial development of deep space exploration capabilities to support extensive human spaceflight missions around and beyond cislunar space. NASA first issued the Phase 1 NextSTEP Broad Agency Announcement to U.S. industries in 2014, which called for innovative cislunar habitation concepts that leveraged commercialization plans for low Earth orbit. These habitats will be part of the Deep Space Gateway (DSG), the cislunar space station planned by NASA for construction in the 2020s. In 2016, Phase 2 of the NextSTEP program selected five commercial partners to develop ground prototypes. A team of NASA research engineers and subject matter experts have been tasked with developing the ground test protocol that will serve as the primary means by which these Phase 2 prototype habitats will be evaluated. Since 2008, this core test team has successfully conducted multiple spaceflight analog mission evaluations utilizing a consistent set of operational products, tools, methods, and metrics to enable the iterative development, testing, analysis, and validation of evolving exploration architectures, operations concepts, and vehicle designs. The purpose of implementing a similar evaluation process for the NextSTEP Phase 2 Habitation Concepts is to consistently evaluate the different commercial partner ground prototypes to provide data-driven, actionable recommendations for Phase 3.

Navigation Operations with Prototype Components of an Automated Real-Time Spacecraft Navigation System

NASA Technical Reports Server (NTRS)

Cangahuala, L.; Drain, T. R.

1999-01-01

At present, ground navigation support for interplanetary spacecraft requires human intervention for data pre-processing, filtering, and post-processing activities; these actions must be repeated each time a new batch of data is collected by the ground data system.

Low cost ground receiving systems for television signals from high powered communications satellites, volume 1

NASA Technical Reports Server (NTRS)

Hesler, J. P.; Hwang, Y. C.; Zampini, J. J.

1972-01-01

The fabrication and evaluation of 10 engineering prototype ground signal processing systems of three converter types are reported for use with satellite television. Target cost converters and cost sensitivity analysis are discussed along with the converter configurations.

Haptics using a smart material for eyes-free interaction in personal devices

NASA Astrophysics Data System (ADS)

Wang, Huihui; Lane, William Brian; Pappas, Devin; Duque, Bryam; Leong, John

2014-03-01

In this paper we present a prototype using a dry ionic polymer metal composite (IPMC) in interactive personal devices such as bracelet, necklace, pocket key chain or mobile devices for haptic interaction when audio or visual feedback is not possible or practical. This prototype interface is an electro-mechanical system that realizes a shape-changing haptic display for information communication. A dry IPMC will change its dimensions due to the electrostatic effect when an electrical potential is provided to them. The IPMC can operate at a lower voltage (less than 2.5V) which is compatible with requirements for personal electrical devices or mobile devices. The prototype consists of the addressable arrays of the IPMCs with different dimensions which are deformable to different shapes with proper handling or customization. 3D printing technology will be used to form supporting parts. Microcontrollers (about 3cm square) from DigiKey will be imbedded into this personal device. An Android based mobile APP will be developed to talk with microcontrollers to control IPMCs. When personal devices receive information signals, the original shape of the prototype will change to another shape related to the specific sender or types of information sources. This interactive prototype can simultaneously realize multiple methods for conveying haptic information such as dimension, force, and texture due to the flexible array design. We conduct several studies of user experience to explore how users' respond to shape change information.

Investigation of Techniques to Reduce Electrostatic Discharge Susceptibility of Hermetically Sealed EEDS

DTIC Science & Technology

1975-07-03

explosive | output requirement. The substitution of RD 1333 lead azide for dextrinated 1 (Figure 8c) did not improve the output, but the modified charge...Pennsylvania 19112 Library Director Army Material Systems Analysis Agency Aberdeen Proving Ground Aberdeen, Maryland 21005 Technical Library

Spectral fingerprint of electrostatic forces between biological cells

NASA Astrophysics Data System (ADS)

Murovec, T.; Brosseau, C.

2015-10-01

The prediction of electrostatic forces (EFs) between biological cells still poses challenges of great scientific importance, e.g., cell recognition, electroporation (EP), and mechanosensing. Frequency-domain finite element simulations explore a variety of cell configurations in the range of parameters typical for eukaryotic cells. Here, by applying an electric field to a pair of layered concentric shells, a prototypical model of a biological cell, we provide numerical evidence that the instantaneous EF changes from repulsion to attraction as the drive frequency of the electric field is varied. We identify crossover frequencies and discuss their dependence as a function of field frequency, conductivity of the extracellular medium, and symmetry of the configuration of cells. We present findings which suggest that the spectrum of EFs depends sensitively on the configuration of cells. We discuss the signatures of the collective behavior of systems with many cells in the spectrum of the EF and highlight a few of the observational consequences that this behavior implies. By looking at different cell configurations, we are able to show that the repulsion-to-attraction transition phenomenon is largely associated with an asymmetric electrostatic screening at very small separation between cells. These findings pave the way for the experimental observation of the electromagnetic properties of efficient and simple models of biological tissues.

Crystal Structures of Beta- and Gammaretrovirus Fusion Proteins Reveal a Role for Electrostatic Stapling in Viral Entry

PubMed Central

Aydin, Halil; Cook, Jonathan D.

2014-01-01

Membrane fusion is a key step in the life cycle of all envelope viruses, but this process is energetically unfavorable; the transmembrane fusion subunit (TM) of the virion-attached glycoprotein actively catalyzes the membrane merger process. Retroviral glycoproteins are the prototypical system to study pH-independent viral entry. In this study, we determined crystal structures of extramembrane regions of the TMs from Mason-Pfizer monkey virus (MPMV) and xenotropic murine leukemia virus-related virus (XMRV) at 1.7-Å and 2.2-Å resolution, respectively. The structures are comprised of a trimer of hairpins that is characteristic of class I viral fusion proteins and now completes a structural library of retroviral fusion proteins. Our results allowed us to identify a series of intra- and interchain electrostatic interactions in the heptad repeat and chain reversal regions. Mutagenesis reveals that charge-neutralizing salt bridge mutations significantly destabilize the postfusion six-helix bundle and abrogate retroviral infection, demonstrating that electrostatic stapling of the fusion subunit is essential for viral entry. Our data indicate that salt bridges are a major stabilizing force on the MPMV and XMRV retroviral TMs and likely provide the key energetics for viral and host membrane fusion. PMID:24131724

Enhanced electrostatic vibrational energy harvesting using integrated opposite-charged electrets

NASA Astrophysics Data System (ADS)

Tao, Kai; Wu, Jin; Tang, Lihua; Hu, Liangxing; Woh Lye, Sun; Miao, Jianmin

2017-04-01

This paper presents a sandwich-structured MEMS electret-based vibrational energy harvester (e-VEH) that has two opposite-charged electrets integrated into a single electrostatic device. Compared to the conventional two-plate configuration where the maximum charge can only be induced when the movable mass reaches its lowest position, the proposed harvester is capable of creating maximum charge induction at both the highest and the lowest extremes, leading to an enhanced output performance. As a proof of concept, an out-of-plane MEMS e-VEH device with an overall volume of about 0.24 cm3 is designed, modeled, fabricated and characterized. A holistic equivalent circuit model incorporating the mechanical dynamic model and two capacitive circuits has been established to study the charge circulations. With the fabricated prototype, the experimental analysis demonstrates the superior performance of the proposed sandwiched e-VEH: the output voltage increases by 80.9% and 18.6% at an acceleration of 5 m s-2 compared to the top electret alone and bottom electret alone configurations, respectively. The experimental results also confirm the waveform derivation with the increase of excitation, which is in good agreement with the circuit simulation results. The proposed sandwiched e-VEH topology provides an effective and convenient methodology for improving the performance of electrostatic energy harvesting devices.

Spectral fingerprint of electrostatic forces between biological cells.

PubMed

Murovec, T; Brosseau, C

2015-10-01

The prediction of electrostatic forces (EFs) between biological cells still poses challenges of great scientific importance, e.g., cell recognition, electroporation (EP), and mechanosensing. Frequency-domain finite element simulations explore a variety of cell configurations in the range of parameters typical for eukaryotic cells. Here, by applying an electric field to a pair of layered concentric shells, a prototypical model of a biological cell, we provide numerical evidence that the instantaneous EF changes from repulsion to attraction as the drive frequency of the electric field is varied. We identify crossover frequencies and discuss their dependence as a function of field frequency, conductivity of the extracellular medium, and symmetry of the configuration of cells. We present findings which suggest that the spectrum of EFs depends sensitively on the configuration of cells. We discuss the signatures of the collective behavior of systems with many cells in the spectrum of the EF and highlight a few of the observational consequences that this behavior implies. By looking at different cell configurations, we are able to show that the repulsion-to-attraction transition phenomenon is largely associated with an asymmetric electrostatic screening at very small separation between cells. These findings pave the way for the experimental observation of the electromagnetic properties of efficient and simple models of biological tissues.

Energy Harvesting with a Liquid-Metal Microfluidic Influence Machine

NASA Astrophysics Data System (ADS)

Conner, Christopher; de Visser, Tim; Loessberg, Joshua; Sherman, Sam; Smith, Andrew; Ma, Shuo; Napoli, Maria Teresa; Pennathur, Sumita; Weld, David

2018-04-01

We describe and demonstrate an alternative energy-harvesting technology based on a microfluidic realization of a Wimshurst influence machine. The prototype device converts the mechanical energy of a pressure-driven flow into electrical energy, using a multiphase system composed of droplets of liquid mercury surrounded by insulating oil. Electrostatic induction between adjacent metal droplets drives charge through external electrode paths, resulting in continuous charge amplification and collection. We demonstrate a power output of 4 nW from the initial prototype and present calculations suggesting that straightforward device optimization could increase the power output by more than 3 orders of magnitude. At that level, the power efficiency of this energy-harvesting mechanism, limited by viscous dissipation, could exceed 90%. The microfluidic context enables straightforward scaling and parallelization, as well as hydraulic matching to a variety of ambient mechanical energy sources, such as human locomotion.

The COROT ground-based archive and access system

NASA Astrophysics Data System (ADS)

Solano, E.; González-Riestra, R.; Catala, C.; Baglin, A.

2002-01-01

A prototype of the COROT ground-based archive and access system is presented here. The system has been developed at LAEFF and it is based on the experience gained at Laboratorio de Astrofisica Espacial y Fisica Fundamental (LAEFF) with the INES (IUE Newly Extracted System) Archive.

ELECTROSTATIC FORCES IN WIND-POLLINATION: PART 2: SIMULATIONS OF POLLEN CAPTURE

EPA Science Inventory

During fair-weather conditions, a 100 V m^-1 electric field exists between positive charge suspended in the air and negative charge distributed on the surfaces of plants and on the ground. The fields surrounding plants are highly complex reaching magnitudes up to 3x106 ...

Electrostatic polymer-based microdeformable mirror for adaptive optics

NASA Astrophysics Data System (ADS)

Zamkotsian, Frederic; Conedera, Veronique; Granier, Hugues; Liotard, Arnaud; Lanzoni, Patrick; Salvagnac, Ludovic; Fabre, Norbert; Camon, Henri

2007-02-01

Future adaptive optics (AO) systems require deformable mirrors with very challenging parameters, up to 250 000 actuators and inter-actuator spacing around 500 μm. MOEMS-based devices are promising for the development of a complete generation of new deformable mirrors. Our micro-deformable mirror (MDM) is based on an array of electrostatic actuators with attachments to a continuous mirror on top. The originality of our approach lies in the elaboration of layers made of polymer materials. Mirror layers and active actuators have been demonstrated. Based on the design of this actuator and our polymer process, realization of a complete polymer-MDM has been done using two process flows: the first involves exclusively polymer materials while the second uses SU8 polymer for structural layers and SiO II and sol-gel for sacrificial layers. The latest shows a better capability in order to produce completely released structures. The electrostatic force provides a non-linear actuation, while AO systems are based on linear matrices operations. Then, we have developed a dedicated 14-bit electronics in order to "linearize" the actuation, using a calibration and a sixth-order polynomial fitting strategy. The response is nearly perfect over our 3×3 MDM prototype with a standard deviation of 3.5 nm; the influence function of the central actuator has been measured. First evaluation on the cross non-linarities has also been studied on OKO mirror and a simple look-up table is sufficient for determining the location of each actuator whatever the locations of the neighbor actuators. Electrostatic MDM are particularly well suited for open-loop AO applications.

Status of Electrostatic Accelerometer Development for Gravity Recovery and Climate Experiment Follow-on Mission (GRACE FO)

NASA Astrophysics Data System (ADS)

Lebat, V.; Boulanger, D.; Christophe, B.; Foulon, B.; Liorzou, F.; Perrot, E.; Huynh, P. A.

2014-12-01

The GRACE FO mission, led by the JPL (Jet Propulsion Laboratory), is an Earth-orbiting gravity mission, continuation of the GRACE mission, which will produce an accurate model of the Earth's gravity field variation providing global climatic data during five years at least. The mission involves two satellites in a loosely controlled tandem formation, with a micro-wave link measuring the inter-satellites distance variation. Earth's mass distribution non-uniformities cause variations of the inter-satellite distance. This variation is measured to recover gravity, after subtracting the non-gravitational contributors, as the residual drag. ONERA (the French Aerospace Lab) is developing, manufacturing and testing electrostatic accelerometers measuring this residual drag applied on the satellites. The accelerometer is composed of two main parts: the Sensor Unit (including the Sensor Unit Mechanics - SUM - and the Front-End Electronic Unit - FEEU) and the Interface Control Unit - ICU. In the Accelerometer Core, located in the Sensor Unit Mechanics, the proof mass is levitated and maintained at the center of an electrode cage by electrostatic forces. Thus, any drag acceleration applied on the satellite involves a variation on the servo-controlled electrostatic suspension of the mass. The voltage on the electrodes providing this electrostatic force is the measurement output of the accelerometer. The impact of the accelerometer defaults (geometry, electronic and parasitic forces) leads to bias, misalignment and scale factor error, non-linearity and noise. Some of these accelerometer defaults are characterized by tests with micro-gravity pendulum bench on ground and with drops in ZARM catapult. The Preliminary Design Review was achieved successfully on November 2013. The Engineering Model (EM) was integrated successfully and is under test, with ground levitation, drops, Electromagnetic Compatibility and thermal vacuum. The complete EM tests will be achieved on October 2014. The Critical Design Review is scheduled at the end of September 2014, and the integration of the first Flight Model will begin on October 2014. The results of the Engineering Model tests and the status of the Flight Models will be presented.

Electrostatic modification of novel materials

NASA Astrophysics Data System (ADS)

Ahn, C. H.; Bhattacharya, A.; di Ventra, M.; Eckstein, J. N.; Frisbie, C. Daniel; Gershenson, M. E.; Goldman, A. M.; Inoue, I. H.; Mannhart, J.; Millis, Andrew J.; Morpurgo, Alberto F.; Natelson, Douglas; Triscone, Jean-Marc

2006-10-01

Application of the field-effect transistor principle to novel materials to achieve electrostatic doping is a relatively new research area. It may provide the opportunity to bring about modifications of the electronic and magnetic properties of materials through controlled and reversible changes of the carrier concentration without modifying the level of disorder, as occurs when chemical composition is altered. As well as providing a basis for new devices, electrostatic doping can in principle serve as a tool for studying quantum critical behavior, by permitting the ground state of a system to be tuned in a controlled fashion. In this paper progress in electrostatic doping of a number of materials systems is reviewed. These include structures containing complex oxides, such as cuprate superconductors and colossal magnetoresistive compounds, organic semiconductors, in the form of both single crystals and thin films, inorganic layered compounds, single molecules, and magnetic semiconductors. Recent progress in the field is discussed, including enabling experiments and technologies, open scientific issues and challenges, and future research opportunities. For many of the materials considered, some of the results can be anticipated by combining knowledge of macroscopic or bulk properties and the understanding of the field-effect configuration developed during the course of the evolution of conventional microelectronics. However, because electrostatic doping is an interfacial phenomenon, which is largely an unexplored field, real progress will depend on the development of a better understanding of lattice distortion and charge transfer at interfaces in these systems.

Double-Cusp type electrostatic Analyzer for SupraThermal ions (DCAST)

NASA Astrophysics Data System (ADS)

Ogasawara, Keiichi; Livi, Stefano; Desai, Mihir; Allegrini, Frederic; McComas, David; John, Joerg-Micha

2016-04-01

Measurements obtained over the last decade have led to a general consensus that the poorly understood suprathermal (ST) tail between ˜2-100 keV/nucleon provides much of the seed population for CME-driven shocks near the Sun and in the interplanetary space. However, existing instruments are not only resource hungry (e.g., power and mass) but also require very long integration times (>days) to measure key properties of the ST ions e.g., anisotropy, energy spectra, composition, and spatial-temporal variations. Our proposed concept of the electrostatic analyzer, employing a toroidal double-shell structure, covers the ST energy between ˜3-200 keV/q ions with higher temporal resolution while using significantly lower resources compared to conventional solar wind instruments covering ST energy range. In this presentation, we describe the concept and show testing results obtained with our laboratory prototype. We will give the expected performance (G-factor, analyzer constant, energy resolution, cross-shell contamination, and UV suppression) based on measurements and simulations.

Numerical Study of Electrostatic Field Distortion on LPTPC End-Plates based on Bulk Micromegas Modules

NASA Astrophysics Data System (ADS)

Bhattacharya, Purba; Bhattacharya, Deb Sankar; Mukhopadhyay, Supratik; Majumdar, Nayana; Bhattacharya, Sudeb; Colas, Paul; Attié, David

2018-02-01

The R&D activities for the linear collider TPC (LC-TPC) are currently working on the adoption of the micro pattern devices for the gaseous amplification stage. Several beam tests have been carried out at DESY with a 5 GeV electron beam in a 1 T superconducting magnet. We worked on a large prototype TPC with an end-plate that was built, for the first time, using seven resistive bulk Micromegas modules. During experiments, reduced signal sensitivity was observed at the boundary of these modules. Electrostatic field distortion near the module boundaries was considered to be the possible major reason behind these observations. In the present work, we will explore this hypothesis through numerical simulation. Our aim has been to understand the origin of distortions observed close to the edges of the test beam modules and to explore the possibility of using the Garfield simulation framework for investigating a phenomenon as complex as distortion.

Control system adds to precipitator efficiency

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gurrole, G.

1978-02-01

An electrostatic precipitator in use at Lion Oil Co., Martinez, Calif., in a fluid catalytic cracking and CO boiler application, was upgraded by mechanical sectionalization of the gas passage and a new electronic control system. The electrostatic precipitator is installed upstream of the CO boiler to handle gas flow up to 4.77 ft/sec, and pressure to 4.5 psi. The independent gas chambers in the electrostatic precipitator were divided by installing gas-tight partition walls to form a total of four electrostatic fields. The precipitator was also equipped with adjustable inlet gas flow-control baffles for even gas distribution. Rows of grounded collectingmore » electrodes are parallel with the flow of gas. The emitting electrode system, powered by separate high-energy transformers for each collecting field, uses silicon-controlled rectifiers and analog electronic networks for rapid response to changing gas and dust conditions. Regulatory requirements call for efficient collection of catalyst fines with no more than 40 lb/hr escaping through the boiler stack. Currently, stack losses average about 38 lb/hr. The installation of two additional control systems with transformers and rectifiers should reduce stack losses to 34 lb/hr.« less

HELIOS dual swept frequency radiometer

NASA Technical Reports Server (NTRS)

White, J. R.

1975-01-01

The HELIOS dual swept frequency radiometer, used in conjunction with a dipole antenna, was designed to measure electromagnetic radiation in space. An engineering prototype was fabricated and tested on the HELIOS spacecraft. Two prototypes and two flight units were fabricated and three of the four units were integrated into the HELIOS spacecraft. Two sets of ground support equipment were provided for checkout of the radiometer.

Virtual prototyping of a semi-active transfemoral prosthetic leg.

PubMed

Lui, Zhen Wei; Awad, Mohammed I; Abouhossein, Alireza; Dehghani-Sanij, Abbas A; Messenger, Neil

2015-05-01

This article presents a virtual prototyping study of a semi-active lower limb prosthesis to improve the functionality of an amputee during prosthesis-environment interaction for level ground walking. Articulated ankle-foot prosthesis and a single-axis semi-active prosthetic knee with active and passive operating modes were considered. Data for level ground walking were collected using a photogrammetric method in order to develop a base-line simulation model and with the hip kinematics input to verify the proposed design. The simulated results show that the semi-active lower limb prosthesis is able to move efficiently in passive mode, and the activation time of the knee actuator can be reduced by approximately 50%. Therefore, this semi-active system has the potential to reduce the energy consumption of the actuators required during level ground walking and requires less compensation from the amputee due to lower deviation of the vertical excursion of body centre of mass. © IMechE 2015.

Application of star identification using pattern matching to space ground systems at GSFC

NASA Technical Reports Server (NTRS)

Fink, D.; Shoup, D.

1994-01-01

This paper reports the application of pattern recognition techniques for star identification based on those proposed by Van Bezooijen to space ground systems for near-real-time attitude determination. A prototype was developed using these algorithms, which was used to assess the suitability of these techniques for support of the X-Ray Timing Explorer (XTE), Submillimeter Wave Astronomy Satellite (SWAS), and the Solar and Heliospheric Observatory (SOHO) missions. Experience with the prototype was used to refine specifications for the operational system. Different geometry tests appropriate to the mission requirements of XTE, SWAS, and SOHO were adopted. The applications of these techniques to upcoming mission support of XTE, SWAS, and SOHO are discussed.

Advantages of Unfair Quantum Ground-State Sampling.

PubMed

Zhang, Brian Hu; Wagenbreth, Gene; Martin-Mayor, Victor; Hen, Itay

2017-04-21

The debate around the potential superiority of quantum annealers over their classical counterparts has been ongoing since the inception of the field. Recent technological breakthroughs, which have led to the manufacture of experimental prototypes of quantum annealing optimizers with sizes approaching the practical regime, have reignited this discussion. However, the demonstration of quantum annealing speedups remains to this day an elusive albeit coveted goal. We examine the power of quantum annealers to provide a different type of quantum enhancement of practical relevance, namely, their ability to serve as useful samplers from the ground-state manifolds of combinatorial optimization problems. We study, both numerically by simulating stoquastic and non-stoquastic quantum annealing processes, and experimentally, using a prototypical quantum annealing processor, the ability of quantum annealers to sample the ground-states of spin glasses differently than thermal samplers. We demonstrate that (i) quantum annealers sample the ground-state manifolds of spin glasses very differently than thermal optimizers (ii) the nature of the quantum fluctuations driving the annealing process has a decisive effect on the final distribution, and (iii) the experimental quantum annealer samples ground-state manifolds significantly differently than thermal and ideal quantum annealers. We illustrate how quantum annealers may serve as powerful tools when complementing standard sampling algorithms.

Data Visualization and Analysis Tools for the Global Precipitation Measurement (GPM) Validation Network

NASA Technical Reports Server (NTRS)

Morris, Kenneth R.; Schwaller, Mathew

2010-01-01

The Validation Network (VN) prototype for the Global Precipitation Measurement (GPM) Mission compares data from the Tropical Rainfall Measuring Mission (TRMM) satellite Precipitation Radar (PR) to similar measurements from U.S. and international operational weather radars. This prototype is a major component of the GPM Ground Validation System (GVS). The VN provides a means for the precipitation measurement community to identify and resolve significant discrepancies between the ground radar (GR) observations and similar satellite observations. The VN prototype is based on research results and computer code described by Anagnostou et al. (2001), Bolen and Chandrasekar (2000), and Liao et al. (2001), and has previously been described by Morris, et al. (2007). Morris and Schwaller (2009) describe the PR-GR volume-matching algorithm used to create the VN match-up data set used for the comparisons. This paper describes software tools that have been developed for visualization and statistical analysis of the original and volume matched PR and GR data.

PhoneSat: Ground Testing of a Phone-Based Prototype Bus

NASA Technical Reports Server (NTRS)

Felix, Carmen; Howard, Benjamin; Reyes, Matthew; Snarskiy, Fedor; Hickman, Ryan; Boshuizen, Christopher; Marshall, William

2010-01-01

Most of the key capabilities that are requisite of a satellite bus are housed in today's smart phones. PhoneSat refers to an initiative to build a ground-based prototype vehicle that could all the basic functionality of a satellite, including attitude control, using a smart Phone as its central hardware. All components used were also low cost Commercial off the Shelf (COTS). In summer 2009, an initial prototype was created using the LEGO Mindstorm toolkit demonstrating simple attitude control. Here we report on a follow up initiative to design, build and test a vehicle based on the Google s smart phone Nexus One. The report includes results from initial thermal-vacuum chamber tests and low altitude sub-orbital rocket flights which show that, at least for short durations, the Nexus One phone is able to withstand key aspects of the space environment without failure. We compare the sensor data from the Phone's accelerometers and magnetometers with that of an external microelectronic inertial measurement unit.

Thermal stress imposed by prototype bilayer and current ground crew chemical defense ensembles: a limited laboratory comparison. Final report, 30 June 1986-1 January 1987

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krock, L.P.; Navalta, R.; Myhre, L.G.

An open bilayer ground-crew chemical defense ensemble (CDE) was proposed to reduce the thermal burden during vapor-only exposure periods. This study compared the thermal-stress profile of the proposed ensemble to that produced by the currently employed closed CDE. Four subjects, alternating ensembles on separate days, walked on a treadmill in an environmental chamber at 5.3 km/h (3.3 mph) and 2% grade (an energy expenditure of 350 kcal/h) for alternating work/rest to achieve significant recovery. Mean total sweat production was lower (1.38 vs. 2.50 liters) and percent sweat evaporation greater (65.7% vs. 30.0%) in the prototype ensemble than in the CDE.more » The prototype ensemble provided greater heat dissipation and allowed more-efficient sweat evaporation which had the double benefit of reducing heat storage and limiting dehydration.« less

Progress toward studies of bubble-geometry Bose-Einstein condensates in microgravity with a ground-based prototype of NASA CAL

NASA Astrophysics Data System (ADS)

Lundblad, Nathan; Jarvis, Thomas; Paseltiner, Daniel; Lannert, Courtney

2016-05-01

We have proposed using NASA's Cold Atom Laboratory (CAL, launching to the International Space Station in 2017) to generate bubble-geometry Bose-Einstein condensates through radiofrequency dressing of an atom-chip magnetic trap. This geometry has not been truly realized terrestrially due to the perturbing influence of gravity, making it an ideal candidate for microgravity investigation aboard CAL. We report progress in the construction of a functional prototype of the orbital BEC apparatus: a compact atom-chip machine loaded by a 2D+MOT source, conventional 3D MOT, quadrupole trap, and transfer coil. We also present preliminary modeling of the dressed trap uniformity, which will crucially inform the geometric closure of the BEC shell surface as atom number, bubble radius, and bubble aspect ratio are varied. Finally, we discuss plans for experimental sequences to be run aboard CAL guided by intuition from ground-based prototype operation. JPL 1502172.

Robowell: An automated process for monitoring ground water quality using established sampling protocols

USGS Publications Warehouse

Granato, G.E.; Smith, K.P.

1999-01-01

Robowell is an automated process for monitoring selected ground water quality properties and constituents by pumping a well or multilevel sampler. Robowell was developed and tested to provide a cost-effective monitoring system that meets protocols expected for manual sampling. The process uses commercially available electronics, instrumentation, and hardware, so it can be configured to monitor ground water quality using the equipment, purge protocol, and monitoring well design most appropriate for the monitoring site and the contaminants of interest. A Robowell prototype was installed on a sewage treatment plant infiltration bed that overlies a well-studied unconfined sand and gravel aquifer at the Massachusetts Military Reservation, Cape Cod, Massachusetts, during a time when two distinct plumes of constituents were released. The prototype was operated from May 10 to November 13, 1996, and quality-assurance/quality-control measurements demonstrated that the data obtained by the automated method was equivalent to data obtained by manual sampling methods using the same sampling protocols. Water level, specific conductance, pH, water temperature, dissolved oxygen, and dissolved ammonium were monitored by the prototype as the wells were purged according to U.S Geological Survey (USGS) ground water sampling protocols. Remote access to the data record, via phone modem communications, indicated the arrival of each plume over a few days and the subsequent geochemical reactions over the following weeks. Real-time availability of the monitoring record provided the information needed to initiate manual sampling efforts in response to changes in measured ground water quality, which proved the method and characterized the screened portion of the plume in detail through time. The methods and the case study described are presented to document the process for future use.

Electrostatic atomization: Effect of electrode materials on electrostatic atomizer performance

NASA Astrophysics Data System (ADS)

Sankaran, Abhilash; Staszel, Christopher; Kashir, Babak; Perri, Anthony; Mashayek, Farzad; Yarin, Alexander

2016-11-01

Electrostatic atomization was studied experimentally with a pointed electrode in a converging nozzle. Experiments were carried out on poorly conductive canola oil where it was observed that electrode material may affect charge transfer. This points at the possible faradaic reactions that can occur at the surfaces of the electrodes. The supply voltage is applied to the sharp electrode and the grounded nozzle body constitutes the counter-electrode. The charge transfer is controlled by the electrochemical reactions on both the electrodes. The electrical performance study of the atomizer issuing a charged oil jet was conducted using three different nozzle body materials - brass, copper and stainless steel. Also, two sharp electrode materials - brass and stainless steel - were tested. The experimental results revealed that both the nozzle body material, as well as the sharp electrode material affected the spray and leak currents. Moreover, the effect of the sharp electrode material is quite significant. This research is supported by NSF Grant 1505276.

Spacecraft Demand Access: Autonomy for Low-Cost Planetary Operations

NASA Technical Reports Server (NTRS)

Sweetnam, Donald

1997-01-01

In this paper we describe a new concept and prototype for dramtically reducing the cost of contact with planetary spacecraft. Known as spacecraft Demand Access, a suite of spacecraft and ground automation technologies, it enables future intelligent spacecraft to act as initiators of cost effective contact with the ground - doing it only when necessary.

Autonomously generating operations sequences for a Mars Rover using AI-based planning

NASA Technical Reports Server (NTRS)

Sherwood, Rob; Mishkin, Andrew; Estlin, Tara; Chien, Steve; Backes, Paul; Cooper, Brian; Maxwell, Scott; Rabideau, Gregg

2001-01-01

This paper discusses a proof-of-concept prototype for ground-based automatic generation of validated rover command sequences from highlevel science and engineering activities. This prototype is based on ASPEN, the Automated Scheduling and Planning Environment. This Artificial Intelligence (AI) based planning and scheduling system will automatically generate a command sequence that will execute within resource constraints and satisfy flight rules.

Learning the Electric Field Concept as Oriented Research Activity

ERIC Educational Resources Information Center

Furio, C.; Guisasola, J.; Almudi, J. M.; Ceberio, M.

2003-01-01

This work is grounded in a constructivistic conception of the learning of science, more particularly on the model known as teaching-learning as oriented research. In accordance with this theoretical basis we have developed an empirical research project to investigate the teaching of electrostatics in high schools. The designs developed have…

High-spin ribbons and antiferromagnetic ordering of a Mn(II)-biradical-Mn(II) complex.

PubMed

Fatila, Elisabeth M; Clérac, Rodolphe; Rouzières, Mathieu; Soldatov, Dmitriy V; Jennings, Michael; Preuss, Kathryn E

2013-09-11

A binuclear metal coordination complex of the first thiazyl-based biradical ligand 1 is reported (1 = 4,6-bis(1,2,3,5-dithiadiazolyl)pyrimidine; hfac =1,1,1,5,5,5,-hexafluoroacetylacetonato-). The Mn(hfac)2-biradical-Mn(hfac)2 complex 2 is a rare example of a discrete, molecular species employing a neutral bridging biradical ligand. It is soluble in common organic solvents and can be easily sublimed as a crystalline solid. Complex 2 has a spin ground state of S(T) = 4 resulting from antiferromagnetic coupling between the S(birad) = 1 biradical bridging ligand and two S(Mn) = 5/2 Mn(II) ions. Electrostatic contacts between atoms with large spin density promote a ferromagnetic arrangement of the moments of neighboring complexes in ribbon-like arrays. Weak antiferromagnetic coupling between these high-spin ribbons stabilizes an ordered antiferromagnetic ground state below 4.5 K. This is an unusual example of magnetic ordering in a molecular metal-radical complex, wherein the electrostatic contacts that direct the crystal packing are also responsible for providing an efficient exchange coupling pathway between molecules.

Aerodynamic Characteristics of Fin- and Flare-Stabilized 25 mm XM910 Prototypes

DTIC Science & Technology

1987-12-01

RESEARCH LABORATORY ABERDEEN PROVING GROUND , MARYL..,,IT - -Si: ,,/ S.. . . .. . . .... .,4 : -- DESTRUMMI NOTICE Destroy this report when it is no...Laboratory, Aberdeen Proving Ground , Maryland, August 1958. (AD 202249) 2. Murphy, C.H., "Data Reduction for the Free Flight Spark Ranges," BRL-R- 900...U.S. Army Ballistic Research Laboratory, Aberdeen Proving Ground , Maryland, February 1954. (AD 35833) 3. Mermagen, Ws.H., Ya~lamanchili, R.J., and

The control system of the 12-m medium-size telescope prototype: a test-ground for the CTA array control

NASA Astrophysics Data System (ADS)

Oya, I.; Anguner, E. A.; Behera, B.; Birsin, E.; Fuessling, M.; Lindemann, R.; Melkumyan, D.; Schlenstedt, S.; Schmidt, T.; Schwanke, U.; Sternberger, R.; Wegner, P.; Wiesand, S.

2014-07-01

The Cherenkov Telescope Array (CTA) will be the next generation ground-based very-high energy -ray observatory. CTA will consist of two arrays: one in the Northern hemisphere composed of about 20 telescopes, and the other one in the Southern hemisphere composed of about 100 telescopes, both arrays containing telescopes of different sizes and types and in addition numerous auxiliary devices. In order to provide a test-ground for the CTA array control, the steering software of the 12-m medium size telescope (MST) prototype deployed in Berlin has been implemented using the tools and design concepts under consideration to be used for the control of the CTA array. The prototype control system is implemented based on the Atacama Large Millimeter/submillimeter Array (ALMA) Common Software (ACS) control middleware, with components implemented in Java, C++ and Python. The interfacing to the hardware is standardized via the Object Linking and Embedding for Process Control Unified Architecture (OPC UA). In order to access the OPC UA servers from the ACS framework in a common way, a library has been developed that allows to tie the OPC UA server nodes, methods and events to the equivalents in ACS components. The front-end of the archive system is able to identify the deployed components and to perform the sampling of the monitoring points of each component following time and value change triggers according to the selected configurations. The back-end of the archive system of the prototype is composed by two different databases: MySQL and MongoDB. MySQL has been selected as storage of the system configurations, while MongoDB is used to have an efficient storage of device monitoring data, CCD images, logging and alarm information. In this contribution, the details and conclusions on the implementation of the control software of the MST prototype are presented.

Hybrid Atom Electrostatic System for Satellite Geodesy

NASA Astrophysics Data System (ADS)

Zahzam, Nassim; Bidel, Yannick; Bresson, Alexandre; Huynh, Phuong-Anh; Liorzou, Françoise; Lebat, Vincent; Foulon, Bernard; Christophe, Bruno

2017-04-01

The subject of this poster comes within the framework of new concepts identification and development for future satellite gravity missions, in continuation of previously launched space missions CHAMP, GRACE, GOCE and ongoing and prospective studies like NGGM, GRACE 2 or E-GRASP. We were here more focused on the inertial sensors that complete the payload of such satellites. The clearly identified instruments for space accelerometry are based on the electrostatic technology developed for many years by ONERA and that offer a high level of performance and a high degree of maturity for space applications. On the other hand, a new generation of sensors based on cold atom interferometry (AI) is emerging and seems very promising in this context. These atomic instruments have already demonstrated on ground impressive results, especially with the development of state-of-the-art gravimeters, and should reach their full potential only in space, where the microgravity environment allows long interaction times. Each of these two types of instruments presents their own advantages which are, for the electrostatic sensors (ES), their demonstrated short term sensitivity and their high TRL, and for AI, amongst others, the absolute nature of the measurement and therefore no need for calibration processes. These two technologies seem in some aspects very complementary and a hybrid sensor bringing together all their assets could be the opportunity to take a big step in this context of gravity space missions. We present here the first experimental association on ground of an electrostatic accelerometer and an atomic accelerometer and underline the interest of calibrating the ES instrument with the AI. Some technical methods using the ES proof-mass as the Raman Mirror seem very promising to remove rotation effects of the satellite on the AI signal. We propose a roadmap to explore further in details and more rigorously this attractive hybridization scheme in order to assess its potential for a future geodesy space mission with theoretical and experimental work.

A repertoire of pyridinium-phenyl-methyl cross-talk through a cascade of intramolecular electrostatic interactions.

PubMed

Acharya, P; Plashkevych, O; Morita, C; Yamada, S; Chattopadhyaya, J

2003-02-21

Direct intramolecular cation-pi interaction between phenyl and pyridinium moieties in 1a(+) has been experimentally evidenced through pH-dependent (1)H NMR titration. The basicity of the pyridinyl group (pK(a) 2.9) in 1a can be measured both from the pH-dependent chemical shifts of the pyridinyl protons as well as from the protons of the neighboring phenyl and methyl groups as a result of electrostatic interaction between the phenyl and the pyridinium ion in 1a(+) at the ground state. The net result of this nearest neighbor electrostatic interaction is that the pyridinium moiety in 1a becomes more basic (pK(a) 2.92) compared to that in the standard 2a (pK(a) 2.56) as a consequence of edge-to-face cation (pyridinium)-pi (phenyl) interaction, giving a free energy of stabilization (DeltaDeltaG(o)pKa) of -2.1 kJ mol(-1). The fact that the pH-dependent downfield shifts of the phenyl and methyl protons give the pK(a) of the pyridine moiety of 1a also suggests that the nearest neighbor cation (pyridinium)-pi (phenyl) interaction also steers the CH (methyl)-pi (phenyl) interaction in tandem. This means that the whole pyridine-phenyl-methyl system in 1a(+) is electronically coupled at the ground state, cross-modulating the physicochemical property of the next neighbor by using the electrostatics as the engine, and the origin of this electrostatics is a far away point in the molecule-the pyridinyl-nitrogen. The relative chemical shift changes and the pK(a) differences show that the cation (pyridinium)-pi (phenyl) interaction is indeed more stable (DeltaDeltaG(o)pKa = -2.1 kJ mol(-1)) than that of the CH (methyl)-pi (phenyl) interaction (DeltaDeltaG(o)pKa = -0.8 kJ mol(-1)). Since the pK(a) of the pyridine moiety in 1a is also obtained through the pH-dependent shifts of both phenyl and methyl protons, it suggests that the net electrostatic mediated charge transfer from the phenyl to the pyridinium and its effect on the CH (methyl)-pi (phenyl) interaction corresponds to DeltaG(o)pKa of the pyridinium ion (approximately 17.5 kJ mol(-1)), which means that the aromatic characters of the phenyl and the pyridinium rings in 1a(+) have been cross-modulated owing to the edge-to-face interaction proportional to this DeltaG(o)pKa change.

High resolution space quartz-flexure accelerometer based on capacitive sensing and electrostatic control technology.

PubMed

Tian, W; Wu, S C; Zhou, Z B; Qu, S B; Bai, Y Z; Luo, J

2012-09-01

High precision accelerometer plays an important role in space scientific and technical applications. A quartz-flexure accelerometer operating in low frequency range, having a resolution of better than 1 ng/Hz(1/2), has been designed based on advanced capacitive sensing and electrostatic control technologies. A high precision capacitance displacement transducer with a resolution of better than 2 × 10(-6) pF/Hz(1/2) above 0.1 Hz, is used to measure the motion of the proof mass, and the mechanical stiffness of the spring oscillator is compensated by adjusting the voltage between the proof mass and the electrodes to induce a proper negative electrostatic stiffness, which increases the mechanical sensitivity and also suppresses the position measurement noise down to 3 × 10(-10) g/Hz(1/2) at 0.1 Hz. A high resolution analog-to-digital converter is used to directly readout the feedback voltage applied on the electrodes in order to suppress the action noise to 4 × 10(-10) g/Hz(1/2) at 0.1 Hz. A prototype of the quartz-flexure accelerometer has been developed and tested, and the preliminary experimental result shows that its resolution comes to about 8 ng/Hz(1/2) at 0.1 Hz, which is mainly limited by its mechanical thermal noise due to low quality factor.

A new environment for multiple spacecraft power subsystem mission operations

NASA Technical Reports Server (NTRS)

Bahrami, K. A.

1990-01-01

The engineering analysis subsystem environment (EASE) is being developed to enable fewer controllers to monitor and control power and other spacecraft engineering subsystems. The EASE prototype has been developed to support simultaneous real-time monitoring of several spacecraft engineering subsystems. It is being designed to assist with offline analysis of telemetry data to determine trends, and to help formulate uplink commands to the spacecraft. An early version of the EASE prototype has been installed in the JPL Space Flight Operations Facility for online testing. The EASE prototype is installed in the Galileo Mission Support Area. The underlying concept, development, and testing of the EASE prototype and how it will aid in the ground operations of spacecraft power subsystems are discussed.

High Power HF Excitation of Low Frequency Stimulated Electrostatic Waves in the Ionospheric Plasma over HAARP

NASA Astrophysics Data System (ADS)

Bernhardt, Paul; Selcher, Craig A.

High Power electromagnetic (EM) waves transmitted from the HAARP facility in Alaska can excite low frequency electrostatic waves by several processes including (1) direct magnetized stimulated Brillouin scatter (MSBS) and (2) parametric decay of high frequency electrostatic waves into electron and ion Bernstein waves. Either an ion acoustic (IA) wave with a frequency less than the ion cyclotron frequency (fCI) or an electrostatic ion cyclotron (EIC) wave just above fCI can be produced by MSBS. The coupled equations describing the MSBS instabil-ity show that the production of both IA and EIC waves is strongly influenced by the wave propagation direction relative to the background magnetic field. Experimental observations of stimulated electromagnetic emissions (SEE) using the HAARP transmitter in Alaska have confirmed the theoretical predictions that only IA waves are excited for propagation along the magnetic zenith and that EIC waves can only be detected with oblique propagation angles. The electron temperature in the heated plasma is obtained from the IA spectrum offsets from the pump frequency. The ion composition can be determined from the measured EIC frequency. Near the second harmonic of the electron cyclotron frequency, the EM pump wave is converted into an electron Bernstein (EB) wave that decays into another EB wave and an ion Bernstein (IB) wave. Strong cyclotron resonance with the EB wave leads to acceleration of the electrons. Ground based SEE observations are related to the theory of low-frequency electrostatic wave generation.

Electrostatic bending response of a charged helix

NASA Astrophysics Data System (ADS)

Zampetaki, A. V.; Stockhofe, J.; Schmelcher, P.

2018-04-01

We explore the electrostatic bending response of a chain of charged particles confined on a finite helical filament. We analyze how the energy difference Δ E between the bent and the unbent helical chain scales with the length of the helical segment and the radius of curvature and identify features that are not captured by the standard notion of the bending rigidity, normally used as a measure of bending tendency in the linear response regime. Using Δ E to characterize the bending response of the helical chain we identify two regimes with qualitatively different bending behaviors for the ground state configuration: the regime of small and the regime of large radius-to-pitch ratio, respectively. Within the former regime, Δ E changes smoothly with the variation of the system parameters. Of particular interest are its oscillations with the number of charged particles encountered for commensurate fillings which yield length-dependent oscillations in the preferred bending direction of the helical chain. We show that the origin of these oscillations is the nonuniformity of the charge distribution caused by the long-range character of the Coulomb interactions and the finite length of the helix. In the second regime of large values of the radius-to-pitch ratio, sudden changes in the ground state structure of the charges occur as the system parameters vary, leading to complex and discontinuous variations in the ground state bending response Δ E .

Diagnostics of the ITER neutral beam test facility.

PubMed

Pasqualotto, R; Serianni, G; Sonato, P; Agostini, M; Brombin, M; Croci, G; Dalla Palma, M; De Muri, M; Gazza, E; Gorini, G; Pomaro, N; Rizzolo, A; Spolaore, M; Zaniol, B

2012-02-01

The ITER heating neutral beam (HNB) injector, based on negative ions accelerated at 1 MV, will be tested and optimized in the SPIDER source and MITICA full injector prototypes, using a set of diagnostics not available on the ITER HNB. The RF source, where the H(-)∕D(-) production is enhanced by cesium evaporation, will be monitored with thermocouples, electrostatic probes, optical emission spectroscopy, cavity ring down, and laser absorption spectroscopy. The beam is analyzed by cooling water calorimetry, a short pulse instrumented calorimeter, beam emission spectroscopy, visible tomography, and neutron imaging. Design of the diagnostic systems is presented.

Thermal Switch for Satellite Temperature Control

NASA Technical Reports Server (NTRS)

Ziad, H.; Slater, T.; vanGerwen, P.; Masure, E.; Preudhomme, F.; Baert, K.

1995-01-01

An active radiator tile (ART) thermal valve has been fabricated using silicon micromachining. Intended for orbital satellite heat control applications, the operational principal of the ART is to control heat flow between two thermally isolated surfaces by bring the surfaces into intimate mechanical contact using electrostatic actuation. Prototype devices have been tested in a vacuum and demonstrate thermal actuation voltages as low as 40 volts, very good thermal insulation in the OFF state, and a large increase in radiative heat flow in the ON state. Thin, anodized aluminum was developed as a coating for high infrared emissivity and high solar reflectance.

Electrostatics of Granular Materials

NASA Technical Reports Server (NTRS)

Marshall, John

2004-01-01

The purpose of the research was to continue developing an understanding of electrostatic phenomena in preparation for any future flight opportunities of the EGM experiment, originally slated for a 2004 Space Station deployment. Work would be based on theoretical assessments, ground-based lab experiments, and reduced-gravity experiments. The ability to examine dipoles in the lab proved to be elusive, and thus, effort was concentrated on monopoles -how materials become charged, the fate of the charge, the role of material type, and so forth. Several significant milestones were achieved in this regard. In regard of the dipoles, experiments were designed in collaboration with the University of Chicago school district who had access to reduced gravity on the KC-135 aircraft. Two experiments were slated to fly last year but were cancelled after the Columbia accident. One of the experiments has been given a second life and will fly sometime in 2005 if the Shuttle flights resume. There remains active interest in the question of electrostatic dipoles within the educational community, and experiments using magnetic dipoles as a substitute are to be examined. The KC-135 experiments will also examine dispersion methods for particles as a verification of possible future techniques in microgravity. Both laboratory and theoretical work established a number of breakthroughs in our understanding of electrostatic phenomena. These breakthroughs are listed in this paper.

The effect of visualizing healthy eaters and mortality reminders on nutritious grocery purchases: an integrative terror management and prototype willingness analysis.

PubMed

McCabe, Simon; Arndt, Jamie; Goldenberg, Jamie L; Vess, Matthew; Vail, Kenneth E; Gibbons, Frederick X; Rogers, Ross

2015-03-01

To use insights from an integration of the terror management health model and the prototype willingness model to inform and improve nutrition-related behavior using an ecologically valid outcome. Prior to shopping, grocery shoppers were exposed to a reminder of mortality (or pain) and then visualized a healthy (vs. neutral) prototype. Receipts were collected postshopping and food items purchased were coded using a nutrition database. Compared with those in the control conditions, participants who received the mortality reminder and who were led to visualize a healthy eater prototype purchased more nutritious foods. The integration of the terror management health model and the prototype willingness model has the potential for both basic and applied advances and offers a generative ground for future research. PsycINFO Database Record (c) 2015 APA, all rights reserved.

Design and validation of a high-voltage levitation circuit for electrostatic accelerometers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, G.; Wu, S. C.; Zhou, Z. B.

2013-12-15

A simple high-voltage circuit with a voltage range of 0 to 900 V and an open-loop bandwidth of 11 kHz is realized by using an operational amplifier and a MOSFET combination. The circuit is used for the levitation of a test mass of 71 g, suspended below the top-electrodes with a gap distance of 57 μm, so that the performance of an electrostatic accelerometer can be tested on the ground. The translation noise of the accelerometer, limited by seismic noise, is about 4 × 10{sup −8} m/s{sup 2}/Hz{sup 1/2} at 0.1 Hz, while the high-voltage coupling noise is one-order ofmore » magnitude lower.« less

Graphene nanoplatelet composite 'paper' as an electrostatic actuator.

PubMed

Yu, Zeyang; Drzal, Lawrence T

2018-08-03

Graphene nanoplatelets (GnP) can be made into a thin 'paper' through vacuum filtration of GnP suspension. Electrodes were fabricated from the compressed GnP paper and then by coating the surface with epoxy. The electrostatic actuator was constructed from two parallel-aligned composite papers fixed at the anode and a cathode connected to ground. The two composite papers would then separate when a voltage was applied. The GnP paper was also modified to increase surface area by introducing porosity or adding ∼10 wt% C750 (GnP with diameter less than 1 μm); or changing the relative permittivity by adding barium titanate particles; or combining these two effects by adding CNCs. Overall the output work could be significantly improved to over 400%.

Infrared instrument support for HyspIRI-TIR

NASA Astrophysics Data System (ADS)

Johnson, William R.; Hook, Simon J.; Foote, Marc; Eng, Bjorn T.; Jau, Bruno

2012-10-01

The Jet Propulsion Laboratory is currently developing an end-to-end instrument which will provide a proof of concept prototype vehicle for a high data rate, multi-channel, thermal instrument in support of the Hyperspectral Infrared Imager (HyspIRI)-Thermal Infrared (TIR) space mission. HyspIRI mission was recommended by the National Research Council Decadal Survey (DS). The HyspIRI mission includes a visible shortwave infrared (SWIR) pushboom spectrometer and a multispectral whiskbroom thermal infrared (TIR) imager. The prototype testbed instrument addressed in this effort will only support the TIR. Data from the HyspIRI mission will be used to address key science questions related to the Solid Earth and Carbon Cycle and Ecosystems focus areas of the NASA Science Mission Directorate. Current designs for the HyspIRI-TIR space borne imager utilize eight spectral bands delineated with filters. The system will have 60m ground resolution, 200mK NEDT, 0.5C absolute temperature resolution with a 5-day repeat from LEO orbit. The prototype instrument will use mercury cadmium telluride (MCT) technology at the focal plane array in time delay integration mode. A custom read out integrated circuit (ROIC) will provide the high speed readout hence high data rates needed for the 5 day repeat. The current HyspIRI requirements dictate a ground knowledge measurement of 30m, so the prototype instrument will tackle this problem with a newly developed interferometeric metrology system. This will provide an absolute measurement of the scanning mirror to an order of magnitude better than conventional optical encoders. This will minimize the reliance on ground control points hence minimizing post-processing (e.g. geo-rectification computations).

High speed, multi-channel, thermal instrument development in support of HyspIRI-TIR

NASA Astrophysics Data System (ADS)

Johnson, William R.; Hook, Simon J.; Foote, Marc; Eng, Bjorn T.; Jau, Bruno

2011-10-01

The Jet Propulsion Laboratory is currently developing an end-to-end instrument which will provide a proof of concept prototype vehicle for a high data rate, multi-channel, thermal instrument in support of the Hyperspectral Infrared Imager (HyspIRI)-Thermal Infrared (TIR) space mission. HyspIRI mission was recommended by the National Research Council Decadal Survey (DS). The HyspIRI mission includes a visible shortwave infrared (SWIR) pushboom spectrometer and a multispectral whiskbroom thermal infrared (TIR) imager. The prototype testbed instrument addressed in this effort will only support the TIR. Data from the HyspIRI mission will be used to address key science questions related to the Solid Earth and Carbon Cycle and Ecosystems focus areas of the NASA Science Mission Directorate. Current designs for the HyspIRI-TIR space borne imager utilize eight spectral bands delineated with filters. The system will have 60m ground resolution, 200mK NEDT, 0.5C absolute temperature resolution with a 5-day repeat from LEO orbit. The prototype instrument will use mercury cadmium telluride (MCT) technology at the focal plane array in time delay integration mode. A custom read out integrated circuit (ROIC) will provide the high speed readout hence high data rates needed for the 5 day repeat. The current HyspIRI requirements dictate a ground knowledge measurement of 30m, so the prototype instrument will tackle this problem with a newly developed interferometeric metrology system. This will provide an absolute measurement of the scanning mirror to an order of magnitude better than conventional optical encoders. This will minimize the reliance on ground control points hence minimizing postprocessing (e.g. geo-rectification computations).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Furuta, H.; Imura, A.; Furuta, Y.

Recently, technique of Gadolinium loaded liquid scintillator (Gd-LS) for reactor neutrino oscillation experiments has attracted attention as a monitor of reactor operation and 'nuclear Gain (GA)' for IAEA safeguards. For the practical use, R and D of the 1 ton class compact detector, which is measurable above ground, is necessary. Especially, it is important to reduce much amount of fast neutron background induced by cosmic muons with data analysis for the measurement above ground. We developed a prototype of the Gd-LS detector with 200 L of the target volume, which has Pulse Shape Discrimination (PSD) ability for the fast neutronmore » reduction with data analysis. Usually, it is well known that it is difficult to keep high fast neutron reduction power of PSD with the large volume size such as the neutrino reactor monitor. We evaluated the PSD ability of our prototype with real fast neutrons induced by the muons in our laboratory above ground, and we could confirm to keep the high fast neutron reduction power with even our large detector size. (authors)« less

Design of high-activity single-atom catalysts via n-p codoping

NASA Astrophysics Data System (ADS)

Wang, Xiaonan; Zhou, Haiyan; Zhang, Xiaoyang; Jia, Jianfeng; Wu, Haishun

2018-03-01

The large-scale synthesis of stable single-atom catalysts (SACs) in experiments remains a significant challenge due to high surface free energy of metal atom. Here, we propose a concise n-p codoping approach, and find it can not only disperse the relatively inexpensive metal, copper (Cu), onto boron (B)-doped graphene, but also result in high-activity SACs. We use CO oxidation on B/Cu codoped graphene as a prototype example, and demonstrate that: (1) a stable SAC can be formed by stronger electrostatic attraction between the metal atom (n-type Cu) and support (p-type B-doped graphene). (2) the energy barrier of the prototype CO oxidation on B/Cu codoped graphene is 0.536 eV by the Eley-Rideal mechanism. Further analysis shows that the spin selection rule can provide well theoretical insight into high activity of our suggested SAC. The concept of n-p codoping may lead to new strategy in large-scale synthesis of stable single-atom catalysts.

Active Dust Mitigation Technology for Thermal Radiators for Lunar Exploration

NASA Technical Reports Server (NTRS)

Calle, C. I.; Buhler, C. R.; Hogue, M. D.; Johansen, M. R.; Hopkins, J. W.; Holloway, N. M. H.; Connell, J. W.; Chen, A.; Irwin, S. A.; Case, S. O.;

Electronic Rearrangement in Molecular Plasmons: An Electron Density and Electrostatic Potential-Based Study.

PubMed

Paul, Mishu; Balanarayan, P

2018-06-05

Plasmonic modes in single-molecule systems have been previously identified by scaling two-electron interactions in calculating excitation energies. Analysis of transition dipole moments for states of polyacenes based on configuration interaction is another method for characterising molecular plasmons. The principal features in the electronic absorption spectra of polyacenes are a low-intensity, lower-in-energy peak and a high-intensity, higher-in-energy peak. From calculations using time-dependent density functional theory with the B3LYP/cc-pVTZ basis set, both these peaks are found to result from the same set of electronic transitions, that is, HOMO-n to LUMO and HOMO to LUMO+n, where n varies as the number of fused rings increases. In this work, the excited states of polyacenes, naphthalene through pentacene, are analysed using electron densities and molecular electrostatic potential (MESP) topography. Compared to other excited states the bright and dark plasmonic states involve the least electron rearrangement. Quantitatively, the MESP topography indicates that the variance in MESP values and the displacement in MESP minima positions, calculated with respect to the ground state, are lowest for plasmonic states. The excited-state electronic density profiles and electrostatic potential topographies suggest the least electron rearrangement for the plasmonic states. Conversely, high electron rearrangement characterises a single-particle excitation. The molecular plasmon can be called an excited state most similar to the ground state in terms of one-electron properties. This is found to be true for silver (Ag 6 ) and sodium (Na 8 ) linear chains as well. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Micogreens Experiment

NASA Image and Video Library

2018-03-13

Kennedy Space Center scientists worked with OSRAM to insert a smart horticulture lighting system prototype into a food production system. The Phytofy RL prototype LED provides similar wavelength capability to a plant growth system currently on orbit. Photofy RL provides another avenue for future investigators conducting flight experiments to perform ground tests prior to flight under similar lighting conditions. The Phytofy RLs have been used to successfully grow microgreens of Wasabi, Tokyo Bekana, Mizuna, Broccoli, Garnet Giant, and Cauliflower.

Use of thermal cycling to reduce adhesion of OTS coated coated MEMS cantilevers

NASA Astrophysics Data System (ADS)

Ali, Shaikh M.; Phinney, Leslie M.

2003-01-01

°Microelectromechanical systems (MEMS) have enormous potential to contribute in diverse fields such as automotive, health care, aerospace, consumer products, and biotechnology, but successful commercial applications of MEMS are still small in number. Reliability of MEMS is a major impediment to the commercialization of laboratory prototypes. Due to the multitude of MEMS applications and the numerous processing and packaging steps, MEMS are exposed to a variety of environmental conditions, making the prediction of operational reliability difficult. In this paper, we investigate the effects of operating temperature on the in-use adhesive failure of electrostatically actuated MEMS microcantilevers coated with octadecyltrichlorosilane (OTS) films. The cantilevers are subjected to repeated temperature cycles and electrostatically actuated at temperatures between 25°C and 300°C in ambient air. The experimental results indicate that temperature cycling of the OTS coated cantilevers in air reduces the sticking probability of the microcantilevers. The sticking probability of OTS coated cantilevers was highest during heating, which decreased during cooling, and was lowest during reheating. Modifications to the OTS release method to increase its yield are also discussed.

Automatic classification of singular elements for the electrostatic analysis of microelectromechanical systems

NASA Astrophysics Data System (ADS)

Su, Y.; Ong, E. T.; Lee, K. H.

2002-05-01

The past decade has seen an accelerated growth of technology in the field of microelectromechanical systems (MEMS). The development of MEMS products has generated the need for efficient analytical and simulation methods for minimizing the requirement for actual prototyping. The boundary element method is widely used in the electrostatic analysis for MEMS devices. However, singular elements are needed to accurately capture the behavior at singular regions, such as sharp corners and edges, where standard elements fail to give an accurate result. The manual classification of boundary elements based on their singularity conditions is an immensely laborious task, especially when the boundary element model is large. This process can be automated by querying the geometric model of the MEMS device for convex edges based on geometric information of the model. The associated nodes of the boundary elements on these edges can then be retrieved. The whole process is implemented in the MSC/PATRAN platform using the Patran Command Language (the source code is available as supplementary data in the electronic version of this journal issue).

Upgrades to the NSTX HHFW antenna

NASA Astrophysics Data System (ADS)

Ellis, R.; Brunkhorst, C.; Hosea, J.

2014-02-01

The High Harmonic Fast Wave (HHFW) antenna for the National Spherical Torus Experiment (NSTX) at PPPL will be upgraded as part of the NSTX upgrade project. Higher magnetic fields and plasma current result in disruption forces on the current straps that can be up to four times the original design values. The current straps on the HHFW antenna are presently fed by coaxial feedthroughs with rigid center conductors. The additional forces on the current straps require a compliant section in the center conductor in order to minimize the forces on the feedthrough. The design of this compliant section has been an integrated effort involving electrostatic calculations in parallel with mechanical and thermal analyses, in order to arrive at a design that is optimized for mechanical, thermal and electrical considerations. The voltage standoff obtained from this design will be verified when a prototype antenna is evaluated on our RF test stand. This paper describes the design of the compliant section of the center conductor, mechanical, thermal and electrostatic calculations, and plans for full implementation of the upgrade on NSTX.

History of the Army Ground Forces. Study Number 11. Training in the Ground Army 1942-1945

DTIC Science & Technology

1948-01-01

beingmodified by the Replace- ment and School Commnd to relax controls and to nake it tactically realistic, -beqam& a prototype for the combat-in-cities exercise...of fillers would nake possible initiation of training soon after activation day), the unit period from 13 to 11 weeks, and the ooabine& period from i...Final Major Revision of the AGF Training Program, 7 June 193 Before 193, an previously noted, Arm Ground Forces had Teen oceeled by the limited use

Function-based design process for an intelligent ground vehicle vision system

NASA Astrophysics Data System (ADS)

Nagel, Robert L.; Perry, Kenneth L.; Stone, Robert B.; McAdams, Daniel A.

2010-10-01

An engineering design framework for an autonomous ground vehicle vision system is discussed. We present both the conceptual and physical design by following the design process, development and testing of an intelligent ground vehicle vision system constructed for the 2008 Intelligent Ground Vehicle Competition. During conceptual design, the requirements for the vision system are explored via functional and process analysis considering the flows into the vehicle and the transformations of those flows. The conceptual design phase concludes with a vision system design that is modular in both hardware and software and is based on a laser range finder and camera for visual perception. During physical design, prototypes are developed and tested independently, following the modular interfaces identified during conceptual design. Prototype models, once functional, are implemented into the final design. The final vision system design uses a ray-casting algorithm to process camera and laser range finder data and identify potential paths. The ray-casting algorithm is a single thread of the robot's multithreaded application. Other threads control motion, provide feedback, and process sensory data. Once integrated, both hardware and software testing are performed on the robot. We discuss the robot's performance and the lessons learned.

Nanosatellite optical downlink experiment: design, simulation, and prototyping

NASA Astrophysics Data System (ADS)

Clements, Emily; Aniceto, Raichelle; Barnes, Derek; Caplan, David; Clark, James; Portillo, Iñigo del; Haughwout, Christian; Khatsenko, Maxim; Kingsbury, Ryan; Lee, Myron; Morgan, Rachel; Twichell, Jonathan; Riesing, Kathleen; Yoon, Hyosang; Ziegler, Caleb; Cahoy, Kerri

2016-11-01

The nanosatellite optical downlink experiment (NODE) implements a free-space optical communications (lasercom) capability on a CubeSat platform that can support low earth orbit (LEO) to ground downlink rates>10 Mbps. A primary goal of NODE is to leverage commercially available technologies to provide a scalable and cost-effective alternative to radio-frequency-based communications. The NODE transmitter uses a 200-mW 1550-nm master-oscillator power-amplifier design using power-efficient M-ary pulse position modulation. To facilitate pointing the 0.12-deg downlink beam, NODE augments spacecraft body pointing with a microelectromechanical fast steering mirror (FSM) and uses an 850-nm uplink beacon to an onboard CCD camera. The 30-cm aperture ground telescope uses an infrared camera and FSM for tracking to an avalanche photodiode detector-based receiver. Here, we describe our approach to transition prototype transmitter and receiver designs to a full end-to-end CubeSat-scale system. This includes link budget refinement, drive electronics miniaturization, packaging reduction, improvements to pointing and attitude estimation, implementation of modulation, coding, and interleaving, and ground station receiver design. We capture trades and technology development needs and outline plans for integrated system ground testing.

A low-cost transportable ground station for capture and processing of direct broadcast EOS satellite data

NASA Technical Reports Server (NTRS)

Davis, Don; Bennett, Toby; Short, Nicholas M., Jr.

1994-01-01

The Earth Observing System (EOS), part of a cohesive national effort to study global change, will deploy a constellation of remote sensing spacecraft over a 15 year period. Science data from the EOS spacecraft will be processed and made available to a large community of earth scientists via NASA institutional facilities. A number of these spacecraft are also providing an additional interface to broadcast data directly to users. Direct broadcast of real-time science data from overhead spacecraft has valuable applications including validation of field measurements, planning science campaigns, and science and engineering education. The success and usefulness of EOS direct broadcast depends largely on the end-user cost of receiving the data. To extend this capability to the largest possible user base, the cost of receiving ground stations must be as low as possible. To achieve this goal, NASA Goddard Space Flight Center is developing a prototype low-cost transportable ground station for EOS direct broadcast data based on Very Large Scale Integration (VLSI) components and pipelined, multiprocessing architectures. The targeted reproduction cost of this system is less than $200K. This paper describes a prototype ground station and its constituent components.

Experiences with a Requirements-Based Programming Approach to the Development of a NASA Autonomous Ground Control System

NASA Technical Reports Server (NTRS)

Hinchey, Michael G.; Rash, James L.; Rouff, Christopher A.; Gracanin, Denis; Erickson, John

2005-01-01

Requirements-to-Design-to-Code (R2D2C) is an approach to the engineering of computer-based systems that embodies the idea of requirements-based programming in system development. It goes further; however, in that the approach offers not only an underlying formalism, but full formal development from requirements capture through to the automatic generation of provably-correct code. As such, the approach has direct application to the development of systems requiring autonomic properties. We describe a prototype tool to support the method, and illustrate its applicability to the development of LOGOS, a NASA autonomous ground control system, which exhibits autonomic behavior. Finally, we briefly discuss other areas where the approach and prototype tool are being considered for application.

Artificial intelligence for multi-mission planetary operations

NASA Technical Reports Server (NTRS)

Atkinson, David J.; Lawson, Denise L.; James, Mark L.

1990-01-01

A brief introduction is given to an automated system called the Spacecraft Health Automated Reasoning Prototype (SHARP). SHARP is designed to demonstrate automated health and status analysis for multi-mission spacecraft and ground data systems operations. The SHARP system combines conventional computer science methodologies with artificial intelligence techniques to produce an effective method for detecting and analyzing potential spacecraft and ground systems problems. The system performs real-time analysis of spacecraft and other related telemetry, and is also capable of examining data in historical context. Telecommunications link analysis of the Voyager II spacecraft is the initial focus for evaluation of the prototype in a real-time operations setting during the Voyager spacecraft encounter with Neptune in August, 1989. The preliminary results of the SHARP project and plans for future application of the technology are discussed.

Influence of strain relaxation in axial [Formula: see text] nanowire heterostructures on their electronic properties.

PubMed

Marquardt, Oliver; Krause, Thilo; Kaganer, Vladimir; Martín-Sánchez, Javier; Hanke, Michael; Brandt, Oliver

2017-05-26

We present a systematic theoretical study of the influence of elastic strain relaxation on the built-in electrostatic potentials and the electronic properties of axial [Formula: see text] nanowire (NW) heterostructures. Our simulations reveal that for a sufficiently large ratio between the thickness of the [Formula: see text] disk and the diameter of the NW, the elastic relaxation leads to a significant reduction of the built-in electrostatic potential in comparison to a planar system of similar layer thickness and In content. In this case, the ground state transition energies approach constant values with increasing thickness of the disk and only depend on the In content, a behavior usually associated to that of a quantum well free of built-in electrostatic potentials. We show that the structures under consideration are by no means field-free, and the built-in potentials continue to play an important role even for ultrathin NWs. In particular, strain and the resulting polarization potentials induce complex confinement features of electrons and holes, which depend on the In content, shape, and dimensions of the heterostructure.

Dynamics of Oscillating and Rotating Liquid Drop using Electrostatic Levitator

NASA Astrophysics Data System (ADS)

Matsumoto, Satoshi; Awazu, Shigeru; Abe, Yutaka; Watanabe, Tadashi; Nishinari, Katsuhiro; Yoda, Shinichi

2006-11-01

In order to understand the nonlinear behavior of liquid drop with oscillatory and/or rotational motions, an experimental study was performed. The electrostatic levitator was employed to achieve liquid drop formation on ground. A liquid drop with about 3 mm in diameter was levitated. The oscillation of mode n=2 along the vertical axis was induced by an external electrostatic force. The oscillatory motions were observed to clarify the nonlinearities of oscillatory behavior. A relationship between amplitude and frequency shift was made clear and the effect of frequency shift on amplitude agreed well with the theory. The frequency shift became larger with increasing the amplitude of oscillation. To confirm the nonlinear effects, we modeled the oscillation by employing the mass-spring-damper system included the nonlinear term. The result indicates that the large-amplitude oscillation includes the effect of nonlinear oscillation. The sound pressure was imposed to rotate the liquid drop along a vertical axis by using a pair of acoustic transducers. The drop transited to the two lobed shape due to centrifugal force when nondimensional angular velocity exceeded to 0.58.

Ferrocene Containing Copolymers with Improved Electrostatic Dissipation Properties for Advanced Applications

NASA Technical Reports Server (NTRS)

Smith, T. M.; Nelson, G. L.

2005-01-01

Electrostatic dissipative polymers are used for a variety of functions. Typical methods utilized to transform electrically insulating polymers into either charge dissipative or conductive materials involve incorporating a conductive filler, conductive polymer, oxidizing the surface using plasma, or incorporating surfactants that act as surface wetting agents. Another approach is to synthesize a block copolymer that is expected to result in better electrical properties with minimal impacts to physical, fire, and thermal properties. One such block that can be added into the main chain of polymers is a diol terminated ferrocene oligomer, which is expected to impart electrostatic dissipative properties into the host polymer while concurrently improving the overall fire properties. Previous work with polyurethanes incorporating a ferrocene oligomer into the main chain resulted in much improved fire retardancy. In dealing with electrostatic dissipative materials the important questions are: how easily does the material charge and how quickly can the charge move to ground. One normally describes the materials conductivity, but conductivity only measures the fastest path for an electron not the slowest path. The slowest path is the one of interest, since it is left on the surface and thus can cause discharges. In order to assess ease of charging and decay times corona charge dissipation measurements can accurately assess these properties by introducing a charge on the surface of the material then measuring the surface voltage and the amount of charge deposited. The charge decay curve then will give an indication of a materials electrostatic dissipation properties. Normally, triboelectric testing can be performed, but results vary. Corona charge dissipation results are more repeatable.

Ultrasensitive detection of nitroexplosive - picric acid via a conjugated polyelectrolyte in aqueous media and solid support.

PubMed

Hussain, Sameer; Malik, Akhtar Hussain; Afroz, Mohammad Adil; Iyer, Parameswar Krishnan

2015-04-28

Picric acid (PA) detection at parts per trillion (ppt) levels is achieved by a conjugated polyelectrolyte (PMI) in 100% aqueous media and on a solid platform using paper strips and chitosan (CS) films. The unprecedented selectivity is accomplished via combination of ground state charge transfer and resonance energy transfer (RET) facilitated by favorable electrostatic interactions.

Sampling and analysis of aircraft engine cold start particles and demonstration of an electrostatic personal particle sampler.

PubMed

Armendariz, Alfredo; Leith, David; Boundy, Maryanne; Goodman, Randall; Smith, Les; Carlton, Gary

2003-01-01

Aircraft engines emit an aerosol plume during startup in extremely cold weather that can drift into areas occupied by flightline ground crews. This study tested a personal sampler used to assess exposure to particles in the plume under challenging field conditions. Area and personal samples were taken at two U.S. Air Force (USAF) flightlines during the winter months. Small tube-and-wire electrostatic precipitators (ESPs) were mounted on a stationary stand positioned behind the engines to sample the exhaust. Other ESPs were worn by ground crews to sample breathing zone concentrations. In addition, an aerodynamic particle sizer 3320 (APS) was used to determine the size distribution of the particles. Samples collected with the ESP were solvent extracted and analyzed with gas chromatography-mass spectrometry. Results indicated that the plume consisted of up to 75 mg/m(3) of unburned jet fuel particles. The APS showed that nearly the entire particle mass was respirable, because the plumes had mass median diameters less than 2 micro m. These tests demonstrated that the ESP could be used at cold USAF flightlines to perform exposure assessments to the cold start particles.

The ground prototype processor: Level-1 production during Sentinel-2 in-orbit acceptance

NASA Astrophysics Data System (ADS)

Petrucci, B.; Dechoz, C.; Lachérade, S.; L'Helguen, C.; Raynaud, J.-L.; Trémas, T.; Picard, C.; Rolland, A.

2015-10-01

Jointly with the European Commission, the Sentinel-2 earth observation optical mission is developed by the European Space Agency (ESA). Relying on a constellation of satellites put in orbit starting mid-2015, Sentinel-2 will be devoted to the monitoring of land and coastal areas worldwide thanks to an imagery at high revisit (5 days with two satellites), high resolution (10m, 20m and 60m) with large swath (290km), and multi-spectral imagery (13 bands in visible and shortwave infra-red). In this framework, the French Space Agency (CNES: Centre National d'Etudes Spatiales) supports ESA on the activities related to Image Quality, defining the image products and prototyping the processing techniques. Scope of this paper is to present the Ground Prototype Processor (GPP) that will be in charge of Level-1 production during Sentinel-2 In Orbit Acceptance phase. GPP has been developed by a European industrial consortium composed of Advanced Computer Systems (ACS), Magellium and DLR on the basis of CNES technical specification of Sentinel-2 data processing and under the joint management of ESA-ESTEC and CNES. It will assure the generation of the products used for Calibration and Validation activities and it will provide the reference data for Sentinel-2 Payload Data Ground Segment Validation. At first, Sentinel-2 end-users products definition is recalled with the associated radiometric and geometric performances; secondly the methods implemented will be presented with an overview of the Ground Image Processing Parameters that need to be tuned during the In Orbit Acceptance phase to assure the required performance of the products. Finally, the complexity of the processing having been showed, the challenges of the production in terms of data volume and processing time will be highlighted. The first Sentinel-2 Level-1 products are shown.

Lyophilization for Water Recovery III, System Design

NASA Technical Reports Server (NTRS)

Litwiller, Eric; Reinhard, Martin; Fisher, John; Flynn, Michael

2005-01-01

Mixed liquid/solid wastes, including feces, water processor effluents, and food waste, can be lyophilized (freeze-dried) to recover the water they contain and stabilize the solids that remain. Our previous research has demonstrated the potential benefits of using thermoelectric heat pumps to build a lyophilizer for processing waste in microgravity. These results were used to build a working prototype suitable for ground- based human testing. This paper describes the prototype design and presents results of functional and performance tests.

Enhanced Software for Scheduling Space-Shuttle Processing

NASA Technical Reports Server (NTRS)

Barretta, Joseph A.; Johnson, Earl P.; Bierman, Rocky R.; Blanco, Juan; Boaz, Kathleen; Stotz, Lisa A.; Clark, Michael; Lebovitz, George; Lotti, Kenneth J.; Moody, James M.;

Dynamics of spherical metallic particles in cylinder electrostatic separators/purifiers.

PubMed

Lu, Hong-Zhou; Li, Jia; Guo, Jie; Xu, Zhen-Ming

2008-08-15

This paper presents a theoretical analysis of the dynamics of spherical metallic particles in electrostatic separators/purifiers (ESPs). The particle equations of motion are numerically solved in two dimensions using a computational algorithm. The ESPs consist of a pair of conductor cylinder electrodes. The upper cylinder is energized by HVdc, while the lower one is grounded and fixed horizontally on a revolvable axis. Some phenomena and aspects of separation process are explained and depicted including lifting off, impact, "motion collapse" and "sudden bouncing". The results reveal that the several phenomena depend on initial position, radius and density of the particle, curvature of the cylinder electrodes, distance between the electrodes and amplitude of the applied voltage. Optimization of the parameters is presented in order to get better separation/purification processes.

Surface charge method for molecular surfaces with curved areal elements I. Spherical triangles

NASA Astrophysics Data System (ADS)

Yu, Yi-Kuo

2018-03-01

Parametrizing a curved surface with flat triangles in electrostatics problems creates a diverging electric field. One way to avoid this is to have curved areal elements. However, charge density integration over curved patches appears difficult. This paper, dealing with spherical triangles, is the first in a series aiming to solve this problem. Here, we lay the ground work for employing curved patches for applying the surface charge method to electrostatics. We show analytically how one may control the accuracy by expanding in powers of the the arc length (multiplied by the curvature). To accommodate not extremely small curved areal elements, we have provided enough details to include higher order corrections that are needed for better accuracy when slightly larger surface elements are used.

Electrostatic hazards of charging of bedclothes and ignition in medical facilities.

PubMed

Endo, Yuta; Ohsawa, Atsushi; Yamaguma, Mizuki

2018-02-26

We investigated the charge generated on bedclothes (cotton and polyester) during bedding exchange with different humidities and the ignitability of an alcohol-based hand sanitizer (72.3 mass% ethanol) due to static spark with different temperatures to identify the hazards of electrostatic shocks and ignitions occurring previously in medical facilities. The results indicated that charging of the polyester bedclothes may induce a human body potential of over about 10 kV, resulting in shocks even at a relative humidity of 50%, and a human body potential of higher than about 8 kV can cause a risk for the ignition of the hand sanitizer. The grounding of human bodies via footwear and flooring, therefore, is essential to avoid such hazards (or to reduce such risks).

Technology Transfer Opportunities: Automated Ground-Water Monitoring, A Proven Technology

USGS Publications Warehouse

Smith, Kirk P.; Granato, Gregory E.

1998-01-01

Introduction The U.S. Geological Survey (USGS) has developed and tested an automated ground-water monitoring system that measures and records values of selected water-quality properties and constituents using protocols approved for manual sampling. Prototypes using the automated process have demonstrated the ability to increase the quantity and quality of data collected and have shown the potential for reducing labor and material costs for ground-water quality data collection. Automated ground-water monitoring systems can be used to monitor known or potential contaminant sites, such as near landfills, underground storage tanks, or other facilities where potential contaminants are stored, to serve as early warning systems monitoring ground-water quality near public water-supply wells, and for ground-water quality research.

Improved Ribbon Bridge (IRB) Prototype Transporter-Operational Test

DTIC Science & Technology

1992-05-01

Department of Defense I Commander US Army Aberdeen Proving Ground I Director, Tochnical Information ATTN, STEAP.MT-U (GE Branch) Defense Advanced... Proving Ground . MD 21005-5071 Defense Nuclear Agency ATTN-. TnL IDirector Washingtm, DC 20305 US Ballistics Research Laboratory ATIN: AMXBR-OD-ST (STINFO...Technology Laboratory Aberden Proving GOfouind MD 21005 Waerown. MA 02172.0001 DLstdbutlon-1 Commmder 1 Commander US Army Electrnics Reswtl and

Integrated Demonstration of Instrument Placement , Robust Execution and Contingent Planning

NASA Technical Reports Server (NTRS)

Pedersen, L.; Bualat, M.; Lees, D.; Smith, D. E.; Korsmeyer, David (Technical Monitor); Washington, R.

2003-01-01

This paper describes an integrated demonstration of ground-based contingent planning, robust execution and autonomous instrument placement for the efficient exploration of a site by a prototype Mars rover.

Comparison ofdvanced turboprop interior noise control ground and flight test data

NASA Technical Reports Server (NTRS)

Simpson, Myles A.; Tran, Boi N.

1992-01-01

Interior noise ground tests conducted on a DC-9 aircraft test section are described. The objectives were to study ground test and analysis techniques for evaluating the effectiveness of interior noise control treatments for advanced turboprop aircraft, and to study the sensitivity of the ground test results to changes in various test conditions. Noise and vibration measurements were conducted under simulated advanced turboprop excitation, for two interior noise control treatment configurations. These ground measurement results were compared with results of earlier UHB (Ultra High Bypass) Demonstrator flight sts with comparable interior treatment configurations. The Demonstrator is an MD-80 test aircraft with the left JT8D engine replaced with a prototype UHB advanced turboprop engine.

Comparison ofdvanced turboprop interior noise control ground and flight test data

NASA Astrophysics Data System (ADS)

Simpson, Myles A.; Tran, Boi N.

Interior noise ground tests conducted on a DC-9 aircraft test section are described. The objectives were to study ground test and analysis techniques for evaluating the effectiveness of interior noise control treatments for advanced turboprop aircraft, and to study the sensitivity of the ground test results to changes in various test conditions. Noise and vibration measurements were conducted under simulated advanced turboprop excitation, for two interior noise control treatment configurations. These ground measurement results were compared with results of earlier UHB (Ultra High Bypass) Demonstrator flight sts with comparable interior treatment configurations. The Demonstrator is an MD-80 test aircraft with the left JT8D engine replaced with a prototype UHB advanced turboprop engine.

Parylene-based active micro space radiator with thermal contact switch

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ueno, Ai; Suzuki, Yuji

2014-03-03

Thermal management is crucial for highly functional spacecrafts exposed to large fluctuations of internal heat dissipation and/or thermal boundary conditions. Since thermal radiation is the only means for heat removal, effective control of radiation is required for advanced space missions. In the present study, a MEMS (Micro Electro Mechanical Systems) active radiator using the contact resistance change has been proposed. Unlike previous bulky thermal louvers/shutters, higher fill factor can be accomplished with an array of electrostatically driven micro diaphragms suspended with polymer tethers. With an early prototype developed with parylene MEMS technologies, radiation heat flux enhancement up to 42% hasmore » been achieved.« less

EUSO-TA prototype telescope

NASA Astrophysics Data System (ADS)

Bisconti, Francesca; JEM-EUSO Collaboration

2016-07-01

EUSO-TA is one of the prototypes developed for the JEM-EUSO project, a space-based large field-of-view telescope to observe the fluorescence light emitted by cosmic ray air showers in the atmosphere. EUSO-TA is a ground-based prototype located at the Telescope Array (TA) site in Utah, USA, where an Electron Light Source and a Central Laser Facility are installed. The purpose of the EUSO-TA project is to calibrate the prototype with the TA fluorescence detector in presence of well-known light sources and cosmic ray air showers. In 2015, the detector started the first measurements and tests using the mentioned light sources have been performed successfully. A first cosmic ray candidate has been observed, as well as stars of different magnitude and color index. Since Silicon Photo-Multipliers (SiPMs) are very promising for fluorescence telescopes of next generation, they are under consideration for the realization of a new prototype of EUSO Photo Detector Module (PDM). The response of this sensor type is under investigation through simulations and laboratory experimentation.

Rapid prototyping facility for flight research in artificial-intelligence-based flight systems concepts

NASA Technical Reports Server (NTRS)

Duke, E. L.; Regenie, V. A.; Deets, D. A.

1986-01-01

The Dryden Flight Research Facility of the NASA Ames Research Facility of the NASA Ames Research Center is developing a rapid prototyping facility for flight research in flight systems concepts that are based on artificial intelligence (AI). The facility will include real-time high-fidelity aircraft simulators, conventional and symbolic processors, and a high-performance research aircraft specially modified to accept commands from the ground-based AI computers. This facility is being developed as part of the NASA-DARPA automated wingman program. This document discusses the need for flight research and for a national flight research facility for the rapid prototyping of AI-based avionics systems and the NASA response to those needs.

A rapid prototyping facility for flight research in advanced systems concepts

NASA Technical Reports Server (NTRS)

Duke, Eugene L.; Brumbaugh, Randal W.; Disbrow, James D.

1989-01-01

The Dryden Flight Research Facility of the NASA Ames Research Facility of the NASA Ames Research Center is developing a rapid prototyping facility for flight research in flight systems concepts that are based on artificial intelligence (AI). The facility will include real-time high-fidelity aircraft simulators, conventional and symbolic processors, and a high-performance research aircraft specially modified to accept commands from the ground-based AI computers. This facility is being developed as part of the NASA-DARPA automated wingman program. This document discusses the need for flight research and for a national flight research facility for the rapid prototyping of AI-based avionics systems and the NASA response to those needs.

Liquid Structures and Physical Properties -- Ground Based Studies for ISS Experiments

NASA Technical Reports Server (NTRS)

Kelton, K. F.; Bendert, J. C.; Mauro, N. A.

2012-01-01

Studies of electrostatically-levitated supercooled liquids have demonstrated strong short- and medium-range ordering in transition metal and alloy liquids, which can influence phase transitions like crystal nucleation and the glass transition. The structure is also related to the liquid properties. Planned ISS experiments will allow a deeper investigation of these results as well as the first investigations of a new type of coupling in crystal nucleation in primary crystallizing liquids, resulting from a linking of the stochastic processes of diffusion with interfacial-attachment. A brief description of the techniques used for ground-based studies and some results relevant to planned ISS investigations are discussed.

STS-40 DTO 647 prototype filter documented under OV-102's middeck subfloor

NASA Image and Video Library

1991-06-14

STS040-34-001 (5-14 June 1991) --- This 35mm scene shows a close-up of a prototype filter designed to remove contamination from air and water, before it flows into the Orbiter's humidity separators. This experiment is part of Development Test Objective (DTO) 647, Water Separator Filter Performance Evaluation. Astronauts Bryan D. O'Connor, mission commander, and Sidney M. Gutierrez, pilot, carried out the test and down linked television to the ground for engineering analysis.

The development of an automated flight test management system for flight test planning and monitoring

NASA Technical Reports Server (NTRS)

Hewett, Marle D.; Tartt, David M.; Duke, Eugene L.; Antoniewicz, Robert F.; Brumbaugh, Randal W.

1988-01-01

The development of an automated flight test management system (ATMS) as a component of a rapid-prototyping flight research facility for AI-based flight systems concepts is described. The rapid-prototyping facility includes real-time high-fidelity simulators, numeric and symbolic processors, and high-performance research aircraft modified to accept commands for a ground-based remotely augmented vehicle facility. The flight system configuration of the ATMS includes three computers: the TI explorer LX and two GOULD SEL 32/27s.

The X-38 prototype of the Crew Return Vehicle is suspended under its giant 7,500-square-foot parafoi

NASA Technical Reports Server (NTRS)

2001-01-01

The X-38 prototype of the Crew Return Vehicle for the International Space Station is suspended under its giant 7,500-square-foot parafoil during its eighth free flight on Thursday, Dec. 13, 2001. A portion of the descent was flown by remote control by a NASA astronaut from a ground vehicle configured like the CRV's interior before the X-38 made an autonomous landing on Rogers Dry Lake.

SCaN Network Ground Station Receiver Performance for Future Service Support

NASA Technical Reports Server (NTRS)

Estabrook, Polly; Lee, Dennis; Cheng, Michael; Lau, Chi-Wung

2012-01-01

Objectives: Examine the impact of providing the newly standardized CCSDS Low Density Parity Check (LDPC) codes to the SCaN return data service on the SCaN SN and DSN ground stations receivers: SN Current Receiver: Integrated Receiver (IR). DSN Current Receiver: Downlink Telemetry and Tracking (DTT) Receiver. Early Commercial-Off-The-Shelf (COTS) prototype of the SN User Service Subsystem Component Replacement (USS CR) Narrow Band Receiver. Motivate discussion of general issues of ground station hardware design to enable simple and cheap modifications for support of future services.

Full-Wave Radio Characterization of Ionospheric Modification at HAARP

DTIC Science & Technology

2015-07-26

Full-Wave Radio Characterization of Ionospheric Modification at HAARP We have studied electrostatic and electromagnetic turbulence stimulated by...radio receivers at HAARP in Alaska, and ground-based radio receivers, incoherent scatter radars, and in-situ measurements from Canadian, ESA, and Polish...363255 San Juan, PR 00936 -3255 31-May-2015 ABSTRACT Final Report: Full-Wave Radio Characterization of Ionospheric Modification at HAARP Report Title We

Ground-Based High-Power Microwave Decoy Discrimination System.

DTIC Science & Technology

1987-12-23

understanding of plasma instabilities, self-induced magnetic effects , space - charge considerations, production of ion currents, etc. 3.3.4 Cross-Field...breakdown, due to small potential differences. Interaction volumes can therefore be large, avoiding breakdown and space - charge effects (at the price...the interference of the incident and reflected wave, and by the electrostatic forces of the surface (positive) and space charge (negative) trapped in

Design and Preliminary Performance Testing of Electronegative Gas Plasma Thruster

NASA Technical Reports Server (NTRS)

Liu, Thomas M.; Schloeder, Natalie R.; Walker, Mitchell L. R.; Polzin, Kurt A.; Dankanich, John W.; Aanesland, Ane

2014-01-01

In classical gridded electrostatic ion thrusters, positively charged ions are generated from a plasma discharge of noble gas propellant and accelerated to provide thrust. To maintain overall charge balance on the propulsion system, a separate electron source is required to neutralize the ion beam as it exits the thruster. However, if high-electronegativity propellant gases (e.g., sulfur hexafluoride) are instead used, a plasma discharge can result consisting of both positively and negatively charged ions. Extracting such electronegative plasma species for thrust generation (e.g., with time-varying, bipolar ion optics) would eliminate the need for a separate neutralizer cathode subsystem. In addition for thrusters utilizing a RF plasma discharge, further simplification of the ion thruster power system may be possible by also using the RF power supply to bias the ion optics. Recently, the PEGASES (Plasma propulsion with Electronegative gases) thruster prototype successfully demonstrated proof-of-concept operations in alternatively accelerating positively and negatively charged ions from a RF discharge of a mixture of argon and sulfur hexafluoride.i In collaboration with NASA Marshall Space Flight Center (MSFC), the Georgia Institute of Technology High-Power Electric Propulsion Laboratory (HPEPL) is applying the lessons learned from PEGASES design and testing to develop a new thruster prototype. This prototype will incorporate design improvements and undergo gridless operational testing and diagnostics checkout at HPEPL in April 2014. Performance mapping with ion optics will be conducted at NASA MSFC starting in May 2014. The proposed paper discusses the design and preliminary performance testing of this electronegative gas plasma thruster prototype.

Evaluation and Verification of Channel Transmission Characteristics of Human Body for Optimizing Data Transmission Rate in Electrostatic-Coupling Intra Body Communication System: A Comparative Analysis

PubMed Central

Tseng, Yuhwai; Su, Chauchin; Ho, Yingchieh

2016-01-01

Background Intra-body communication is a new wireless scheme for transmitting signals through the human body. Understanding the transmission characteristics of the human body is therefore becoming increasingly important. Electrostatic-coupling intra-body communication system in a ground-free situation that integrate electronic products that are discretely located on individuals, such as mobile phones, PDAs, wearable computers, and biomedical sensors, are of particular interest. Materials and Methods The human body is modeled as a simplified Resistor-Capacitor network. A virtual ground between the transmitter and receiver in the system is represented by a resister-capacitor network. Value of its resistance and capacitance are determined from a system perspective. The system is characterized by using a mathematical unit step function in digital baseband transmission scheme with and without Manchester code. As a result, the signal-to-noise and to-intersymbol-interference ratios are improved by manipulating the load resistor. The data transmission rate of the system is optimized. A battery-powered transmitter and receiver are developed to validate the proposal. Results A ground-free system fade signal energy especially for a low-frequency signal limited system transmission rate. The system transmission rate is maximized by simply manipulating the load resistor. Experimental results demonstrate that for a load resistance of 10k−50k Ω, the high-pass 3 dB frequency of the band-pass channel is 400kHz−2MHz in the worst-case scenario. The system allows a Manchester-coded baseband signal to be transmitted at speeds of up to 20M bit per second with signal-to-noise and signal-to-intersymbol-interference ratio of more than 10 dB. Conclusion The human body can function as a high speed transmission medium with a data transmission rate of 20Mbps in an electrostatic-coupling intra-body communication system. Therefore, a wideband signal can be transmitted directly through the human body with a good signal-to-noise quality of 10 dB if the high-pass 3 dB frequency is suitably selected. PMID:26866602

Evaluation and Verification of Channel Transmission Characteristics of Human Body for Optimizing Data Transmission Rate in Electrostatic-Coupling Intra Body Communication System: A Comparative Analysis.

PubMed

Tseng, Yuhwai; Su, Chauchin; Ho, Yingchieh

2016-01-01

Intra-body communication is a new wireless scheme for transmitting signals through the human body. Understanding the transmission characteristics of the human body is therefore becoming increasingly important. Electrostatic-coupling intra-body communication system in a ground-free situation that integrate electronic products that are discretely located on individuals, such as mobile phones, PDAs, wearable computers, and biomedical sensors, are of particular interest. The human body is modeled as a simplified Resistor-Capacitor network. A virtual ground between the transmitter and receiver in the system is represented by a resister-capacitor network. Value of its resistance and capacitance are determined from a system perspective. The system is characterized by using a mathematical unit step function in digital baseband transmission scheme with and without Manchester code. As a result, the signal-to-noise and to-intersymbol-interference ratios are improved by manipulating the load resistor. The data transmission rate of the system is optimized. A battery-powered transmitter and receiver are developed to validate the proposal. A ground-free system fade signal energy especially for a low-frequency signal limited system transmission rate. The system transmission rate is maximized by simply manipulating the load resistor. Experimental results demonstrate that for a load resistance of 10k-50k Ω, the high-pass 3 dB frequency of the band-pass channel is 400kHz-2MHz in the worst-case scenario. The system allows a Manchester-coded baseband signal to be transmitted at speeds of up to 20M bit per second with signal-to-noise and signal-to-intersymbol-interference ratio of more than 10 dB. The human body can function as a high speed transmission medium with a data transmission rate of 20Mbps in an electrostatic-coupling intra-body communication system. Therefore, a wideband signal can be transmitted directly through the human body with a good signal-to-noise quality of 10 dB if the high-pass 3 dB frequency is suitably selected.

Secure Web-based Ground System User Interfaces over the Open Internet

NASA Technical Reports Server (NTRS)

Langston, James H.; Murray, Henry L.; Hunt, Gary R.

1998-01-01

A prototype has been developed which makes use of commercially available products in conjunction with the Java programming language to provide a secure user interface for command and control over the open Internet. This paper reports successful demonstration of: (1) Security over the Internet, including encryption and certification; (2) Integration of Java applets with a COTS command and control product; (3) Remote spacecraft commanding using the Internet. The Java-based Spacecraft Web Interface to Telemetry and Command Handling (Jswitch) ground system prototype provides these capabilities. This activity demonstrates the use and integration of current technologies to enable a spacecraft engineer or flight operator to monitor and control a spacecraft from a user interface communicating over the open Internet using standard World Wide Web (WWW) protocols and commercial off-the-shelf (COTS) products. The core command and control functions are provided by the COTS Epoch 2000 product. The standard WWW tools and browsers are used in conjunction with the Java programming technology. Security is provided with the current encryption and certification technology. This system prototype is a step in the direction of giving scientist and flight operators Web-based access to instrument, payload, and spacecraft data.

A Prototype JFACC: General George C. Kenney

DTIC Science & Technology

1994-06-01

Corps, as well as air forces from Australia and New Zealand . Many accounts of the Battles for Leyte and Luzon center around ground and naval forces...St Clair Streett USA Royal New Zealand Air Force (RNZAF) Royal Australian Air Force (RAAF) Air Command Organization SWPA June 15, 1944 Figure 5...Ground Task Force OPCON Operational Command POA Pacific Ocean Areas RAAF Royal Australian Air Force RNZAF Royal New Zealand Air Force SAP

The readout and control system of the mid-size telescope prototype of the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Oya, I.; Anguner, O.; Behera, B.; Birsin, E.; Fuessling, M.; Melkumyan, D.; Schmidt, T.; Schwanke, U.; Sternberger, R.; Wegner, P.; Wiesand, S.; Cta Consortium,the

2014-06-01

The Cherenkov Telescope Array (CTA) is one of the major ground-based astronomy projects being pursued and will be the largest facility for ground-based y-ray observations ever built. CTA will consist of two arrays: one in the Northern hemisphere composed of about 20 telescopes, and the other one in the Southern hemisphere composed of about 100 telescopes, both arrays containing telescopes of different type and size. A prototype for the Mid-Size Telescope (MST) with a diameter of 12 m has been installed in Berlin and is currently being commissioned. This prototype is composed of a mechanical structure, a drive system and mirror facets mounted with powered actuators to enable active control. Five Charge-Coupled Device (CCD) cameras, and a wide set of sensors allow the evaluation of the performance of the instrument. The design of the control software is following concepts and tools under evaluation within the CTA consortium in order to provide a realistic test-bed for the middleware: 1) The readout and control system for the MST prototype is implemented with the Atacama Large Millimeter/submillimeter Array (ALMA) Common Software (ACS) distributed control middleware; 2) the OPen Connectivity-Unified Architecture (OPC UA) is used for hardware access; 3) the document oriented MongoDB database is used for an efficient storage of CCD images, logging and alarm information: and 4) MySQL and MongoDB databases are used for archiving the slow control monitoring data and for storing the operation configuration parameters. In this contribution, the details of the implementation of the control system for the MST prototype telescope are described.

Prototype Vector Machine for Large Scale Semi-Supervised Learning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Kai; Kwok, James T.; Parvin, Bahram

2009-04-29

Practicaldataminingrarelyfalls exactlyinto the supervisedlearning scenario. Rather, the growing amount of unlabeled data poses a big challenge to large-scale semi-supervised learning (SSL). We note that the computationalintensivenessofgraph-based SSLarises largely from the manifold or graph regularization, which in turn lead to large models that are dificult to handle. To alleviate this, we proposed the prototype vector machine (PVM), a highlyscalable,graph-based algorithm for large-scale SSL. Our key innovation is the use of"prototypes vectors" for effcient approximation on both the graph-based regularizer and model representation. The choice of prototypes are grounded upon two important criteria: they not only perform effective low-rank approximation of themore » kernel matrix, but also span a model suffering the minimum information loss compared with the complete model. We demonstrate encouraging performance and appealing scaling properties of the PVM on a number of machine learning benchmark data sets.« less

Prototype development of a Geostationary Synthetic Thinned Aperture Radiometer (GeoSTAR)

NASA Technical Reports Server (NTRS)

Kangaslahti, Pekka; Tanner, Alan; Wilson, William; Dinardo, Steve; Lambrigsten, Bjorn

2005-01-01

Weather prediction and hurricane tracking would greatly benefit of a continuous imaging capability of a hemisphere at millimeter wave frequencies. We are developing a synthetic thinned aperture radiometer (STAR) prototype operating from 50 to 56 GHz as a ground-based testbed to demonstrate the technologies needed to do full earth disk atmospheric temperature soundings from Geostationary orbit with very high spatial resolution. The prototype consists of a Y-array of 24 MMIC receivers that are compact units implemented with low noise InP MMIC LNAs, second harmonic I-Q mixers, low power IF amplifiers and include internal digital bias control with serial line communication to enable low cost testing and system integration. Furthermore, this prototype STAR includes independent LO and noise calibration signal phase switching circuitry for each arm of the Y-array to verify the operation and calibration of the system.

A second generation 50 Mbps VLSI level zero processing system prototype

NASA Technical Reports Server (NTRS)

Harris, Jonathan C.; Shi, Jeff; Speciale, Nick; Bennett, Toby

1994-01-01

Level Zero Processing (LZP) generally refers to telemetry data processing functions performed at ground facilities to remove all communication artifacts from instrument data. These functions typically include frame synchronization, error detection and correction, packet reassembly and sorting, playback reversal, merging, time-ordering, overlap deletion, and production of annotated data sets. The Data Systems Technologies Division (DSTD) at Goddard Space Flight Center (GSFC) has been developing high-performance Very Large Scale Integration Level Zero Processing Systems (VLSI LZPS) since 1989. The first VLSI LZPS prototype demonstrated 20 Megabits per second (Mbp's) capability in 1992. With a new generation of high-density Application-specific Integrated Circuits (ASIC) and a Mass Storage System (MSS) based on the High-performance Parallel Peripheral Interface (HiPPI), a second prototype has been built that achieves full 50 Mbp's performance. This paper describes the second generation LZPS prototype based upon VLSI technologies.

NASA charging analyzer program: A computer tool that can evaluate electrostatic contamination

NASA Technical Reports Server (NTRS)

Stevens, N. J.; Roche, J. C.; Mandell, M. J.

1978-01-01

A computer code, the NASA Charging Analyzer Program (NASCAP), was developed to study the surface charging of bodies subjected to geomagnetic substorm conditions. This program will treat the material properties of a surface in a self-consistent manner and calculate the electric fields in space due to the surface charge. Trajectories of charged particles in this electric field can be computed to determine if these particles enhance surface contamination. A preliminary model of the Spacecraft Charging At The High Altitudes (SCATHA) satellite was developed in the NASCAP code and subjected to a geomagnetic substorm environment to investigate the possibility of electrostatic contamination. The results indicate that differential voltages will exist between the spacecraft ground surfaces and the insulator surfaces. The electric fields from this differential charging can enhance the contamination of spacecraft surfaces.

Analysis of interior noise ground and flight test data for advanced turboprop aircraft applications

NASA Technical Reports Server (NTRS)

Simpson, M. A.; Tran, B. N.

1991-01-01

Interior noise ground tests conducted on a DC-9 aircraft test section are described. The objectives were to study ground test and analysis techniques for evaluating the effectiveness of interior noise control treatments for advanced turboprop aircraft, and to study the sensitivity of the ground test results to changes in various test conditions. Noise and vibration measurements were conducted under simulated advanced turboprop excitation, for two interior noise control treatment configurations. These ground measurement results were compared with results of earlier UHB (Ultra High Bypass) Demonstrator flight tests with comparable interior treatment configurations. The Demonstrator is an MD-80 test aircraft with the left JT8D engine replaced with a prototype UHB advanced turboprop engine.

Analysis of interior noise ground and flight test data for advanced turboprop aircraft applications

NASA Astrophysics Data System (ADS)

Simpson, M. A.; Tran, B. N.

1991-08-01

Interior noise ground tests conducted on a DC-9 aircraft test section are described. The objectives were to study ground test and analysis techniques for evaluating the effectiveness of interior noise control treatments for advanced turboprop aircraft, and to study the sensitivity of the ground test results to changes in various test conditions. Noise and vibration measurements were conducted under simulated advanced turboprop excitation, for two interior noise control treatment configurations. These ground measurement results were compared with results of earlier UHB (Ultra High Bypass) Demonstrator flight tests with comparable interior treatment configurations. The Demonstrator is an MD-80 test aircraft with the left JT8D engine replaced with a prototype UHB advanced turboprop engine.

New approach to improve the energy density of hybrid electret-dielectric elastomer generators

NASA Astrophysics Data System (ADS)

Lagomarsini, Clara; Jean-Mistral, Claire; Monfray, Stephane; Sylvestre, Alain

2017-04-01

Harvesting human kinetic energy to produce electricity is an attractive alternative to batteries for applications in wearable electronic devices and smart textile. Dielectric elastomers generators (DEGs) represent one of the most promising technologies for these applications. Nevertheless, one of the main disadvantages of these structures is the need of an external polarization source to perform the energetic cycle. In the present work, a hybrid electret-dielectric elastomer generator in DEG mode is presented. In this configuration, the electret material is used as polarization source of a classical DEG, i.e. an electrostatic generator based on electrical capacitance variation. The electrical energy output in this mode (1.06mJ.g-1) could be higher than the one obtained using a classical electret mode (0.55mJ.g-1), i.e. charges recombination. In this paper, the operation principle of the hybrid generator will be fully described and the design rules for the realization of the prototype will be presented. The experimental data obtained from the prototype will be compared to the results of FEM simulations.

A knowledge-based system for prototypical reasoning

NASA Astrophysics Data System (ADS)

Lieto, Antonio; Minieri, Andrea; Piana, Alberto; Radicioni, Daniele P.

2015-04-01

In this work we present a knowledge-based system equipped with a hybrid, cognitively inspired architecture for the representation of conceptual information. The proposed system aims at extending the classical representational and reasoning capabilities of the ontology-based frameworks towards the realm of the prototype theory. It is based on a hybrid knowledge base, composed of a classical symbolic component (grounded on a formal ontology) with a typicality based one (grounded on the conceptual spaces framework). The resulting system attempts to reconcile the heterogeneous approach to the concepts in Cognitive Science with the dual process theories of reasoning and rationality. The system has been experimentally assessed in a conceptual categorisation task where common sense linguistic descriptions were given in input, and the corresponding target concepts had to be identified. The results show that the proposed solution substantially extends the representational and reasoning 'conceptual' capabilities of standard ontology-based systems.

Research on ground-based LWIR hyperspectral imaging remote gas detection

NASA Astrophysics Data System (ADS)

Yang, Zhixiong; Yu, Chunchao; Zheng, Weijian; Lei, Zhenggang; Yan, Min; Yuan, Xiaochun; Zhang, Peizhong

2015-10-01

The new progress of ground-based long-wave infrared remote sensing is presented, which describes the windowing spatial and temporal modulation Fourier spectroscopy imaging in details. The prototype forms the interference fringes based on the corner-cube of spatial modulation of Michelson interferometer, using cooled long-wave infrared photovoltaic staring FPA (focal plane array) detector. The LWIR hyperspectral imaging is achieved by the process of collection, reorganization, correction, apodization, FFT etc. from data cube. Noise equivalent sensor response (NESR), which is the sensitivity index of CHIPED-1 LWIR hyperspectral imaging prototype, can reach 5.6×10-8W/(cm-1.sr.cm2) at single sampling. Hyperspectral imaging is used in the field of organic gas VOC infrared detection. Relative to wide band infrared imaging, it has some advantages. Such as, it has high sensitivity, the strong anti-interference ability, identify the variety, and so on.

Influence of strain relaxation in axial {{In}}_{x}{{Ga}}_{1-x}{\\rm{N}}/{GaN} nanowire heterostructures on their electronic properties

NASA Astrophysics Data System (ADS)

Marquardt, Oliver; Krause, Thilo; Kaganer, Vladimir; Martín-Sánchez, Javier; Hanke, Michael; Brandt, Oliver

2017-05-01

We present a systematic theoretical study of the influence of elastic strain relaxation on the built-in electrostatic potentials and the electronic properties of axial {{In}}x{{Ga}}1-x{{N}}/{GaN} nanowire (NW) heterostructures. Our simulations reveal that for a sufficiently large ratio between the thickness of the {{In}}x{{Ga}}1-x{{N}} disk and the diameter of the NW, the elastic relaxation leads to a significant reduction of the built-in electrostatic potential in comparison to a planar system of similar layer thickness and In content. In this case, the ground state transition energies approach constant values with increasing thickness of the disk and only depend on the In content, a behavior usually associated to that of a quantum well free of built-in electrostatic potentials. We show that the structures under consideration are by no means field-free, and the built-in potentials continue to play an important role even for ultrathin NWs. In particular, strain and the resulting polarization potentials induce complex confinement features of electrons and holes, which depend on the In content, shape, and dimensions of the heterostructure.

Martian Atmospheric Pressure Static Charge Elimination Tool

NASA Technical Reports Server (NTRS)

Johansen, Michael R.

2014-01-01

A Martian pressure static charge elimination tool is currently in development in the Electrostatics and Surface Physics Laboratory (ESPL) at NASA's Kennedy Space Center. In standard Earth atmosphere conditions, static charge can be neutralized from an insulating surface using air ionizers. These air ionizers generate ions through corona breakdown. The Martian atmosphere is 7 Torr of mostly carbon dioxide, which makes it inherently difficult to use similar methods as those used for standard atmosphere static elimination tools. An initial prototype has been developed to show feasibility of static charge elimination at low pressure, using corona discharge. A needle point and thin wire loop are used as the corona generating electrodes. A photo of the test apparatus is shown below. Positive and negative high voltage pulses are sent to the needle point. This creates positive and negative ions that can be used for static charge neutralization. In a preliminary test, a floating metal plate was charged to approximately 600 volts under Martian atmospheric conditions. The static elimination tool was enabled and the voltage on the metal plate dropped rapidly to -100 volts. This test data is displayed below. Optimization is necessary to improve the electrostatic balance of the static elimination tool.

Simulation of Electrostatic Actuation in Interdigitated Comb Drive MEMS Resonator for Energy Harvester Applications

NASA Astrophysics Data System (ADS)

Sathya, S.; Pavithra, M.; Muruganand, S.

2016-09-01

This paper presents an actuation mechanism based on the interdigitated comb drive MEMS resonator. The important role of that device is to establish MEMS resonators for the second order systems. Comb drive model is one of the basic model which uses the principle of electrostatic and force can be generated for the capacitive sensors. This work is done by overlapping movable and fixed comb fingers which produces an energy. The specific range of the polyimide material properties of young's modulus of 3.1GPa and density of 1300 Kg/m3. Results are shown in the structural domain performance of a lateral motion which corresponds to the applying voltage between the interdigitated comb fingers. It has laterally driven about 40pm with driving voltage. Also the resonance frequency 24Hz and 15Hz with high quality factors are depending on the spring length 260pm and 360pm and structure thickness of 2μm and 5 μm. Here Finite element method (FEM) is used to simulate the various physics scenario and it is designed as two dimensional structure multiphysics domain. The prototype of comb drive MEMS resonator has been suitable for energy harvesting system applications.

Wiring design for the control of electromagnetic interference (EMI)

NASA Technical Reports Server (NTRS)

Kopasakis, George

1995-01-01

Wiring design is only one important aspect of EMI control. Other important areas for EMI are: circuit design, filtering, grounding, bonding, shielding, lighting, electrostatic discharge (ESD), transient suppression, and electromagnetic pulse (EMP). Topics covered include: wire magnetic field emissions at low frequencies; wire radiated magnetic field emissions at frequencies; wire design guidelines for EMI control; wire design guidelines for EMI control; high frequency emissions from cables; and pulse frequency spectra.

Implications of possible shuttle charging. [prediction analysis techniques for insulation and electrical grounding against ionospheric conductivity

NASA Technical Reports Server (NTRS)

Taylor, W. W. L.

1979-01-01

Shuttle charging is discussed and two analyses of shuttle charging are performed. The first predicts the effective collecting area of a wire grid, biased with the respect to the potential of the magnetoplasma surrounding it. The second predicts the intensity of broadband electromagnetic noise that is emitted when surface electrostatic discharges occur between the beta cloth and the wire grid sewn on it.

Containerless solidification of BiFeO3 oxide under microgravity

NASA Astrophysics Data System (ADS)

Yu, Jianding; Arai, Yasutomo; Koshikawa, Naokiyo; Ishikawa, Takehito; Yoda, Shinichi

1999-07-01

Containerless solidification of BiFeO3 oxide has been carried out under microgravity with Electrostatic Levitation Furnace (ELF) aboard on the sounding rocket (TR-IA). It is a first containerless experiment using ELF under microgravity for studying the solidification of oxide insulator material. Spherical BiFeO3 sample with diameter of 5mm was heated by two lasers in oxygen and nitrogen mixing atmosphere, and the sample position by electrostatic force under pinpoint model and free drift model. In order to compare the solidification behavior in microgravity with on ground, solidification experiments of BiFeO3 in crucible and drop tube were carried out. In crucible experiment, it was very difficult to get single BiFeO3 phase, because segregation of Fe2O3 occured very fast and easily. In drop tube experiment, fine homogeneous BiFeO3 microstructure was obtained in a droplet about 300 μm. It implies that containerless processing can promote the phase selection in solidification. In microgravity experiment, because the heating temperature was lower than that of estimated, the sample was heated into Fe2O3+liquid phase region. Fe2O3 single crystal grew on the surface of the spherical sample, whose sample was clearly different from that observed in ground experiments.

VLF Transmitter Signal Power Loss to Quasi-Electrostatic Whistler Mode Waves in Regions Containing Plasma Density Irregularities

NASA Astrophysics Data System (ADS)

Bell, T. F.; Foust, F.; Inan, U. S.; Lehtinen, N. G.

2010-12-01

The energetic particles comprising the Earth’s radiation belts are an important component of Space Weather. The commonly accepted model of the quasi-steady radiation belts developed by Abel and Thorne [1998] proposes that VLF signals from powerful ground based transmitters determine the lifetimes of energetic radiation belt electrons (100 keV-1.5 MeV) on L shells in the range 1.3-2.8. The primary mechanism of interaction is pitch angle scattering during gyro-resonance. Recent observations [Starks et al., 2008] from multiple spacecraft suggest that the actual night time intensity of VLF transmitter signals in the radiation belts is approximately 20 dB below the level assumed in the Abel and Thorne model and approximately 10 dB below model values during the day. In this work we discuss one mechanism which might be responsible for a large portion of this intensity discrepancy. The mechanism is linear mode coupling between electromagnetic whistler mode waves and quasi-electrostatic whistler mode waves. As VLF electromagnetic whistler mode waves propagate through regions containing small scale (2-100 m) magnetic-field-aligned plasma density irregularities, they excite quasi-electrostatic whistler mode waves, and this excitation represents a power loss for the input waves. We construct plausible models of the irregularities in order to use numerical simulations to determine the characteristics of the mode coupling mechanism and the conditions under which the input VLF waves can lose significant power to the excited quasi-electrostatic whistler mode waves.

Radio Emissions from Electrical Activity in Martian Dust Storms

NASA Astrophysics Data System (ADS)

Majid, W.; Arabshahi, S.; Kocz, J.; Schulter, T.; White, L.

2017-12-01

Dust storms on Mars are predicted to be capable of producing electrostatic fields and discharges, even larger than those in dust storms on Earth. There are three key elements in the characterization of Martian electrostatic discharges: dependence on Martian environmental conditions, event rate, and the strength of the generated electric fields. The detection and characterization of electric activity in Martian dust storms has important implications for habitability, and preparations for human exploration of the red planet. Furthermore, electrostatic discharges may be linked to local chemistry and plays an important role in the predicted global electrical circuit. Because of the continuous Mars telecommunication needs of NASA's Mars-based assets, the Deep Space Network (DSN) is the only facility in the world that combines long term, high cadence, observing opportunities with large sensitive telescopes, making it a unique asset worldwide in searching for and characterizing electrostatic activity from large scale convective dust storms at Mars. We will describe a newly inaugurated program at NASA's Madrid Deep Space Communication Complex to carry out a long-term monitoring campaign to search for and characterize the entire Mars hemisphere for powerful discharges during routine tracking of spacecraft at Mars on an entirely non-interfering basis. The ground-based detections will also have important implications for the design of a future instrument that could make similar in-situ measurements from orbit or from the surface of Mars, with far greater sensitivity and duty cycle, opening up a new window in our understanding of the Martian environment.

Modeling the Electric Potential and Surface Charge Density Near Charged Thunderclouds

NASA Astrophysics Data System (ADS)

Neel, Matthew Stephen

2018-03-01

Thundercloud charge separation, or the process by which the bottom portion of a cloud gathers charge and the top portion of the cloud gathers the opposite charge, is still not thoroughly understood. Whatever the mechanism, though, a charge separation definitely exists and can lead to electrostatic discharge via cloud-to-cloud lightning and cloud-to-ground lightning. We wish to examine the latter form, in which upward leaders from Earth connect with downward leaders from the cloud to form a plasma channel and produce lightning. Much of the literature indicates that the lower part of a thundercloud becomes negatively charged while the upper part becomes positively charged via convective charging, although the opposite polarity can certainly exist along with various, complex intra-cloud currents. It is estimated that >90% of cloud-to-ground lightning is "negative lightning," or the flow of charges from the bottom of the cloud, while the remaining <10% of lightning strikes is "positive lightning," or the flow of charges from the top of the cloud. We wish to understand the electric potential surrounding charged thunderclouds as well as the resulting charge density on the surface of Earth below them. In this paper we construct a simple and adaptable model that captures the very basic features of the cloud/ground system and that exhibits conditions favorable for both forms of lightning. In this way, we provide a practical application of electrostatic dipole physics as well as the method of images that can serve as a starting point for further modeling and analysis by students.

Control and Non-Payload Communications (CNPC) Prototype Radio - Generation 2 Flight Test Report

NASA Technical Reports Server (NTRS)

Ishac, Joseph A.; Iannicca, Dennis C.; Shalkhauser, Kurt A.; Kachmar, Brian A.

2014-01-01

NASA Glenn Research Center conducted a series of flight tests for the purpose of evaluating air-to-ground communications links for future unmanned aircraft systems (UAS). The primary objective of the test effort was to evaluate the transition of the aircraft communications from one ground station to the next, and to monitor data flow during the "hand-off" event. To facilitate the testing, ground stations were installed at locations in Cleveland, Ohio and Albany, Ohio that each provides line-of-sight radio communications with an overflying aircraft. This report describes results from the flight tests including flight parameters, received signal strength measurements, data latency times, and performance observations for the air-to-ground channel.

The automated ground network system

NASA Technical Reports Server (NTRS)

Smith, Miles T.; Militch, Peter N.

1993-01-01

The primary goal of the Automated Ground Network System (AGNS) project is to reduce Ground Network (GN) station life-cycle costs. To accomplish this goal, the AGNS project will employ an object-oriented approach to develop a new infrastructure that will permit continuous application of new technologies and methodologies to the Ground Network's class of problems. The AGNS project is a Total Quality (TQ) project. Through use of an open collaborative development environment, developers and users will have equal input into the end-to-end design and development process. This will permit direct user input and feedback and will enable rapid prototyping for requirements clarification. This paper describes the AGNS objectives, operations concept, and proposed design.

An intelligent position-specific training system for mission operations

NASA Technical Reports Server (NTRS)

Schneider, M. P.

1992-01-01

Marshall Space Flight Center's (MSFC's) payload ground controller training program provides very good generic training; however, ground controller position-specific training can be improved by including position-specific training systems in the training program. This report explains why MSFC needs to improve payload ground controller position-specific training. The report describes a generic syllabus for position-specific training systems, a range of system designs for position-specific training systems, and a generic development process for developing position-specific training systems. The report also describes a position-specific training system prototype that was developed for the crew interface coordinator payload operations control center ground controller position. The report concludes that MSFC can improve the payload ground controller training program by incorporating position-specific training systems for each ground controller position; however, MSFC should not develop position-specific training systems unless payload ground controller position experts will be available to participate in the development process.

Extracting renewable energy from a salinity difference using a capacitor.

PubMed

Brogioli, Doriano

2009-07-31

Completely renewable energy can be produced by using water solutions of different salinity, like river water and sea water. Many different methods are already known, but development is still at prototype stage. Here I report a novel method, based on electric double-layer capacitor technology. Two porous electrodes, immersed in the salt solution, constitute a capacitor. It is first charged, then the salt solution is brought into contact with fresh water. The electrostatic energy increases as the salt concentration of the solution is reduced due to diffusion. This device can be used to turn sources of salinity difference into completely renewable sources of energy. An experimental demonstration is given, and performances and possible improvements are discussed.

ED01-0146-4

NASA Image and Video Library

2001-04-28

Helios Prototype crew chief Marshall MacCready of AeroVironment, Inc., carefully monitors motor runs during ground checkout of the solar-powered flying wing prior to its first flight from the U.S. Navy's Pacific Missile Range Facility on Kaua'i, Hawaii.

ED01-0146-3

NASA Image and Video Library

2001-04-28

The 247-foot length of the Helios prototype wing is in evidence as the high-altitude, solar-powered flying wing rests on its ground dolly during pre-flight tests at the U.S. Navy's Pacific Missile Range Facility on Kaua'i, Hawaii.

Automatic Weather Station (AWS) Lidar

NASA Technical Reports Server (NTRS)

Rall, Jonathan A. R.; Campbell, James; Abshire, James B.; Spinhirne, James D.; Smith, David E. (Technical Monitor)

2001-01-01

A ground based, autonomous, low power atmospheric lidar instrument is being developed at NASA Goddard Space Flight Center. We report on the design and anticipated performance of the proposed instrument and show data from two prototype lidar instruments previously deployed to Antarctica.

Grounding Headphones for Protection Against ESD

NASA Technical Reports Server (NTRS)

Peters, John; Youngquist, Robert C.

2004-01-01

A simple alternative technique has been devised protecting delicate equipment against electrostatic discharge (ESD) in settings in which workers wear communication headsets. In the original setting in which the technique was devised, the workers who wear the headsets also wear anti-ESD grounding straps on their wrists. The alternative technique eliminates the need for the wrist grounding straps by providing for grounding through the headsets. In place of the electrically insulating foam pads on the headsets, one installs pads made of electrically conductive foam like that commonly used to protect electronic components. Grounding wires are attached to the conductive foam pads, then possibly to the shielding cable which may be grounded to the backshell on the connector. The efficacy of this technique in protecting against ESD has been verified in experiments. The electrical resistance of the pads is a few megohms - about the same as that of a human body between the fingers of opposite hands and, hence, low enough for grounding. The only drawback of the technique is that care must be taken to place the foam pads in contact with the user s skin: any hair that comes between the foam pads and the skin must be pushed aside because hair is electrically insulating and thus prevents adequate grounding.

Parametric Modeling as a Technology of Rapid Prototyping in Light Industry

NASA Astrophysics Data System (ADS)

Tomilov, I. N.; Grudinin, S. N.; Frolovsky, V. D.; Alexandrov, A. A.

2016-04-01

The paper deals with the parametric modeling method of virtual mannequins for the purposes of design automation in clothing industry. The described approach includes the steps of generation of the basic model on the ground of the initial one (obtained in 3D-scanning process), its parameterization and deformation. The complex surfaces are presented by the wireframe model. The modeling results are evaluated with the set of similarity factors. Deformed models are compared with their virtual prototypes. The results of modeling are estimated by the standard deviation factor.

The Gravity-Probe-B relativity gyroscope experiment - Development of the prototype flight instrument

NASA Technical Reports Server (NTRS)

Turneaure, J. P.; Everitt, C. W. F.; Parkinson, B. W.; Bardas, D.; Breakwell, J. V.

1989-01-01

The Gravity-Probe-B relativity gyroscope experiment (GP-B) will measure the geodetic and frame-dragging precession rates of gyroscopes in a 650 km high polar orbit about the earth. The goal is to measure these two effects, which are predicted by Einstein's General Theory of Relativity, to 0.01 percent (geodetic) and 1 percent (frame-dragging). This paper presents the development progress for full-size prototype flight hardware including the gyroscopes, gyro readout and magnetic shielding system, and an integrated ground test instrument.

The X-38 prototype of the Crew Return Vehicle is suspended under its giant 7,500-square-foot parafoil during its eighth free flight on Thursday, December 13, 2001

NASA Image and Video Library

2001-12-13

The X-38 prototype of the Crew Return Vehicle for the International Space Station is suspended under its giant 7,500-square-foot parafoil during its eighth free flight on Thursday, Dec. 13, 2001. A portion of the descent was flown by remote control by a NASA astronaut from a ground vehicle configured like the CRV's interior before the X-38 made an autonomous landing on Rogers Dry Lake.

Rapid Prototyping-Unmanned Combat Air Vehicle (UCAV)/Sensorcraft

DTIC Science & Technology

2008-01-01

model. RP may prove to be the fastest means to create a bridge between these CFD and experimental ground testing databases . In the past, it took...UCAV X-45A wind tunnel model within the /RB) ment FD results provide a database of global surface and off-body measurements. It is imperative t...extend the knowledge database for a given aircraft configuration beyond the ground test envelope and into the fligh regime. Working in tandem, in an

A rigorous and simpler method of image charges

NASA Astrophysics Data System (ADS)

Ladera, C. L.; Donoso, G.

2016-07-01

The method of image charges relies on the proven uniqueness of the solution of the Laplace differential equation for an electrostatic potential which satisfies some specified boundary conditions. Granted by that uniqueness, the method of images is rightly described as nothing but shrewdly guessing which and where image charges are to be placed to solve the given electrostatics problem. Here we present an alternative image charges method that is based not on guessing but on rigorous and simpler theoretical grounds, namely the constant potential inside any conductor and the application of powerful geometric symmetries. The aforementioned required uniqueness and, more importantly, guessing are therefore both altogether dispensed with. Our two new theoretical fundaments also allow the image charges method to be introduced in earlier physics courses for engineering and sciences students, instead of its present and usual introduction in electromagnetic theory courses that demand familiarity with the Laplace differential equation and its boundary conditions.

Electromagnetic radiation by parametric decay of upper hybrid waves in ionospheric modification experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leyser, T.B.

1994-06-01

A nonlinear dispersion relation for the parametric decay of an electrostatic upper hybrid wave into an ordinary mode electromagnetic wave, propagating parallel to the ambient magnetic field, and an electrostatic low frequency wave, being either a lower hybrid wave or a high harmonic ion Bernstein wave, is derived. The coherent and resonant wave interaction is considered to take place in a weakly magnetized and collisionless Vlasov plasma. The instability growth rate is computed for parameter values typical of ionospheric modification experiments, in which a powerful high frequency electromagnetic pump wave is injected into the ionospheric F-region from ground-based transmitters. Themore » electromagnetic radiation which is excited by the decaying upper hybrid wave is found to be consistent with the prominent and commonly observed downshifted maximum (DM) emission in the spectrum of stimulated electromagnetic emission.« less

Electrostatic Charging of the Pathfinder Rover

NASA Technical Reports Server (NTRS)

Siebert, Mark W.; Kolecki, Joseph C.

1996-01-01

The Mars Pathfinder mission will send a lander and a rover to the martian surface. Because of the extremely dry conditions on Mars, electrostatic charging of the rover is expected to occur as it moves about. Charge accumulation may result in high electrical potentials and discharge through the martian atmosphere. Such discharge could interfere with the operation of electrical elements on the rover. A strategy was sought to mitigate this charge accumulation as a precautionary measure. Ground tests were performed to demonstrate charging in laboratory conditions simulating the surface conditions expected at Mars. Tests showed that a rover wheel, driven at typical rover speeds, will accumulate electrical charge and develop significant electrical potentials (average observed, 110 volts). Measurements were made of wheel electrical potential, and wheel capacitance. From these quantities, the amount of absolute charge was estimated. An engineering solution was developed and recommended to mitigate charge accumulation. That solution has been implemented on the actual rover.

Electrostatic Spectrograph with a Wide Range of Simultaneously Recorded Energies Composed of Two Coaxial Electrodes with Closed End Faces and a Discrete Combined External Electrode

NASA Astrophysics Data System (ADS)

Fishkova, T. Ya.

2018-01-01

An optimal set of geometric and electrical parameters of a high-aperture electrostatic charged-particle spectrograph with a range of simultaneously recorded energies of E/ E min = 1-50 has been found by computer simulation, which is especially important for the energy analysis of charged particles during fast processes in various materials. The spectrograph consists of two coaxial electrodes with end faces closed by flat electrodes. The external electrode with a conical-cylindrical form is cut into parts with potentials that increase linearly, except for the last cylindrical part, which is electrically connected to the rear end electrode. The internal cylindrical electrode and the front end electrode are grounded. In the entire energy range, the system is sharply focused on the internal cylindrical electrode, which provides an energy resolution of no worse than 3 × 10-3.

Roles Played by Electrostatic Waves in Producing Radio Emissions

NASA Technical Reports Server (NTRS)

Cairns, Iver H.

2000-01-01

Processes in which electromagnetic radiation is produced directly or indirectly via intermediate waves are reviewed. It is shown that strict theoretical constraints exist for electrons to produce nonthermal levels of radiation directly by the Cerenkov or cyclotron resonances. In contrast, indirect emission processes in which intermediary plasma waves are converted into radiation are often favored on general and specific grounds. Four classes of mechanisms involving the conversion of electrostatic waves into radiation are linear mode conversion, hybrid linear/nonlinear mechanisms, nonlinear wave-wave and wave-particle processes, and radiation from localized wave packets. These processes are reviewed theoretically and observational evidence summarized for their occurrence. Strong evidence exists that specific nonlinear wave processes and mode conversion can explain quantitatively phenomena involving type III solar radio bursts and ionospheric emissions. On the other hand, no convincing evidence exists that magnetospheric continuum radiation is produced by mode conversion instead of nonlinear wave processes. Further research on these processes is needed.

Ferroelectric nanotraps for polar molecules

NASA Astrophysics Data System (ADS)

Dutta, Omjyoti; Giedke, G.

2018-02-01

We propose and analyze an electrostatic-optical nanoscale trap for cold diatomic polar molecules. The main ingredient of our proposal is a square array of ferroelectric nanorods with alternating polarization. We show that, in contrast to electrostatic traps using the linear Stark effect, a quadratic Stark potential supports long-lived trapped states. The molecules are kept at a fixed height from the nanorods by a standing-wave optical dipole trap. For the molecules and materials considered, we find nanotraps with trap frequency up to 1 MHz, ground-state width ˜20 nm with lattice periodicity of ˜200 nm . Analyzing the loss mechanisms due to nonadiabaticity, surface-induced radiative transitions, and laser-induced transitions, we show the existence of trapped states with lifetime ˜1 s , competitive with current traps created via optical mechanisms. As an application we extend our discussion to a one-dimensional (1D) array of nanotraps to simulate a long-range spin Hamiltonian in our structure.

A three dimensional dynamic study of electrostatic charging in materials

NASA Technical Reports Server (NTRS)

Katz, I.; Parks, D. E.; Mandell, M. J.; Harvey, J. M.; Brownell, D. H., Jr.; Wang, S. S.; Rotenberg, M.

1977-01-01

A description is given of the physical models employed in the NASCAP (NASA Charging Analyzer Program) code, and several test cases are presented. NASCAP dynamically simulates the charging of an object made of conducting segments which may be entirely or partially covered with thin dielectric films. The object may be subject to either ground test or space user-specified environments. The simulation alternately treats (1) the tendency of materials to accumulate and emit charge when subject to plasma environment, and (2) the consequent response of the charged particle environment to an object's electrostatic field. Parameterized formulations of the emission properties of materials subject to bombardment by electrons, protons, and sunlight are presented. Values of the parameters are suggested for clean aluminum, Al2O3, clean magnesium, MgO, SiO2 kapton, and teflon. A discussion of conductivity in thin dielectrics subject to radiation and high fields is given, together with a sample calculation.

Early warning system for aftershocks

USGS Publications Warehouse

Bakun, W.H.; Fischer, F.G.; Jensen, E.G.; VanSchaack, J.

1994-01-01

A prototype early warning system to provide San Francisco and Oakland, California a few tens-of-seconds warning of incoming strong ground shaking from already-occurred M ≧ 3.7 aftershocks of the magnitude 7.1 17 October 1989 Loma Prieta earthquake was operational on 28 October 1989. The prototype system consisted of four components: ground motion sensors in the epicentral area, a central receiver, a radio repeater, and radio receivers. One of the radio receivers was deployed at the California Department of Transportation (CALTRANS) headquarters at the damaged Cypress Street section of the I-880 freeway in Oakland, California on 28 October 1989 and provided about 20 sec of warning before shaking from the M 4.5 Loma Prieta aftershock that occurred on 2 November 1989 at 0550 UTC. In its first 6 months of operation, the system generated triggers for all 12 M > 3.7 aftershocks for which trigger documentation is preserved, did not trigger on any M ≦ 3.6 aftershocks, and produced one false trigger as a result of a now-corrected single point of failure design flaw. Because the prototype system demonstrated that potentially useful warnings of strong shaking from aftershocks are feasible, the USGS has completed a portable early warning system for aftershocks that can be deployed anywhere.

Explosive Testing of Class 1.3 Rocket Booster Propellant

DTIC Science & Technology

1994-08-01

molds were lined with 0.025 mm (0.001 in.) Velostat conductive plastic sheet and sprayed with a mold release that dried leaving fine Teflon powder... Velostat sheet (0.03 in.) was wrapped around the sample and grounded for improved electrostatic safety. Similar to previous cylinder tests, the...layer of thin Velostat plastic sheet, its contribution to camera viewing distortion of the flame front is not known. Overall, an average velocity over

Expert operator's associate: A knowledge based system for spacecraft control

NASA Technical Reports Server (NTRS)

Nielsen, Mogens; Grue, Klaus; Lecouat, Francois

1991-01-01

The Expert Operator's Associate (EOA) project is presented which studies the applicability of expert systems for day-to-day space operations. A prototype expert system is developed, which operates on-line with an existing spacecraft control system at the European Space Operations Centre, and functions as an 'operator's assistant' in controlling satellites. The prototype is demonstrated using an existing real-time simulation model of the MARECS-B2 telecommunication satellite. By developing a prototype system, the extent to which reliability and effectivens of operations can be enhanced by AI based support is examined. In addition the study examines the questions of acquisition and representation of the 'knowledge' for such systems, and the feasibility of 'migration' of some (currently) ground-based functions into future spaceborne autonomous systems.

An intelligent ground operator support system

NASA Technical Reports Server (NTRS)

Goerlach, Thomas; Ohlendorf, Gerhard; Plassmeier, Frank; Bruege, Uwe

1994-01-01

This paper presents first results of the project 'Technologien fuer die intelligente Kontrolle von Raumfahrzeugen' (TIKON). The TIKON objective was the demonstration of feasibility and profit of the application of artificial intelligence in the space business. For that purpose a prototype system has been developed and implemented for the operation support of the Roentgen Satellite (ROSAT), a scientific spacecraft designed to perform the first all-sky survey with a high-resolution X-ray telescope and to investigate the emission of specific celestial sources. The prototype integrates a scheduler and a diagnosis tool both based on artificial intelligence techniques. The user interface is menu driven and provides synoptic displays for the visualization of the system status. The prototype has been used and tested in parallel to an already existing operational system.

Ground and excited state dipole moments of some flavones using solvatochromic methods: An experimental and theoretical study

NASA Astrophysics Data System (ADS)

Kumar, Sanjay; Kapoor, Vinita; Bansal, Ritu; Tandon, H. C.

2018-03-01

The absorption and fluorescence characteristics of biologically active flavone derivatives 6-Hydroxy-7,3‧,4‧,5‧-tetramethoxyflavone (6HTMF) and 7-Hydroxy-6,3‧,4‧,5‧-tetramethoxyflavone (7HTMF) are studied at room temperature (298 K) in solvents of different polarities. Excited state dipole moments of these compounds have been determined using the solvatochromic shift method based on the microscopic solvent polarity parameter ETN . Dipole moments in excited state were found to be higher than those in the ground state in both the molecules. A reasonable agreement has been observed between experimental and theoretically calculated dipole moments (using AM1 method). Slightly large value of ground and excited state dipole moments of 7HTMF than 6HTMF are in conformity with predicted electrostatic potential maps. Our results would be helpful in understanding use of these compounds as tunable dye lasers, optical brighteners and biosensors.

Ferroelectric Switching by the Grounded Scanning Probe Microscopy Tip

DOE PAGES

Ievlev, Anton V.; Morozovska, A. N.; Shur, Vladimir Ya.; ...

2015-06-19

The process of polarization reversal by the tip of scanning probe microscope was intensively studied for last two decades. Number of the abnormal switching phenomena was reported by the scientific groups worldwide. In particularly it was experimentally and theoretically shown that slow dynamics of the surface screening controls kinetics of the ferroelectric switching, backswitching and relaxation and presence of the charges carriers on the sample surface and in the sample bulk significantly change polarization reversal dynamics. Here we experimentally demonstrated practical possibility of the history dependent polarization reversal by the grounded SPM tip. This phenomenon was attributed to induction ofmore » the slowly dissipating charges into the surface of the grounded tip that enables polarization reversal under the action of the produced electric field. Analytical and numerical electrostatic calculations allow additional insight into nontrivial abnormal switching phenomena reported earlier.« less

The « 3-D donut » electrostatic analyzer for millisecond timescale electron measurements in the solar wind

NASA Astrophysics Data System (ADS)

Berthomier, M.; Techer, J. D.

2017-12-01

Understanding electron acceleration mechanisms in planetary magnetospheres or energy dissipation at electron scale in the solar wind requires fast measurement of electron distribution functions on a millisecond time scale. Still, since the beginning of space age, the instantaneous field of view of plasma spectrometers is limited to a few degrees around their viewing plane. In Earth's magnetosphere, the NASA MMS spacecraft use 8 state-of-the-art sensor heads to reach a time resolution of 30 milliseconds. This costly strategy in terms of mass and power consumption can hardly be extended to the next generation of constellation missions that would use a large number of small-satellites. In the solar wind, using the same sensor heads, the ESA THOR mission is expected to reach the 5ms timescale in the thermal energy range, up to 100eV. We present the « 3-D donut » electrostatic analyzer concept that can change the game for future space missions because of its instantaneous hemispheric field of view. A set of 2 sensors is sufficient to cover all directions over a wide range of energy, e.g. up to 1-2keV in the solar wind, which covers both thermal and supra-thermal particles. In addition, its high sensitivity compared to state of the art instruments opens the possibility of millisecond time scale measurements in space plasmas. With CNES support, we developed a high fidelity prototype (a quarter of the full « 3-D donut » analyzer) that includes all electronic sub-systems. The prototype weights less than a kilogram. The key building block of the instrument is an imaging detector that uses EASIC, a low-power front-end electronics that will fly on the ESA Solar Orbiter and on the NASA Parker Solar Probe missions.

COST Action TU1208 - Working Group 1 - Design and realisation of Ground Penetrating Radar equipment for civil engineering applications

NASA Astrophysics Data System (ADS)

Pajewski, Lara; Benedetto, Andrea; D'Amico, Sebastiano; Ferrara, Vincenzo; Frezza, Fabrizio; Persico, Raffaele; Tosti, Fabio

2017-04-01

This work aims at presenting the main results achieved by Working Group (WG) 1 "Novel Ground Penetrating Radar instrumentation" of the COST (European COoperation in Science and Technology) Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar" (www.cost.eu, www.GPRadar.eu). The principal goal of the Action, which started in April 2013 and is ending in October 2017, is to exchange and increase scientific-technical knowledge and experience of Ground Penetrating Radar techniques in civil engineering, whilst promoting throughout Europe the effective use of this safe non-destructive technique. The Action involves more than 300 Members from 28 COST Countries, a Cooperating State, 6 Near Neighbour Countries and 6 International Partner Countries. The most interesting achievements of WG1 include: 1. The state of the art on GPR systems and antennas was composed; merits and limits of current GPR systems in civil engineering applications were highlighted and open issues were identified. 2. The Action investigated the new challenge of inferring mechanical (strength and deformation) properties of flexible pavement from electromagnetic data. A semi-empirical method was developed by an Italian research team and tested over an Italian test site: a good agreement was found between the values measured by using a light falling weight deflectometer (LFWD) and the values estimated by using the proposed semi-empirical method, thereby showing great promises for large-scale mechanical inspections of pavements using GPR. Subsequently, the method was tested on a real scale, on an Italian road in the countryside: again, a good agreement between LFWD and GPR data was achieved. As a third step, the method was tested at larger scale, over three different road sections within the districts of Madrid and Guadalajara, in Spain: GPR surveys were carried out at the speed of traffic for a total of 39 kilometers, approximately; results were collected by using different GPR antennas provided by the Italian company IDS Ingegneria dei Sistemi; in cooperation with the Spanish company Euroconsult, an instrumented lorry equipped with a curviameter was used in the same road sections. Curviameter and GPR results were compared, with very good agreement. 3. A reconfigurable stepped-frequency GPR prototype was improved and widely tested. The original version of this prototype was designed and realised in Italy, in 2008. In June 2014, with the support of the Action TU1208 (and in particular by exploiting the Short Term Scientific Mission (STSM) networking tool), this prototype was brought to Norway: tests were carried out in laboratory, on roads and archaelogical sites; results were compared with those obtained by using a commercial system manufactured by the Norwegian manufacturer 3d-radar. As a result of this work, it was possible to understand how to improve the Italian prototype. Changes to the hardware were implemented in cooperation with the company Florence Engineering. In the improved version of the prototype, a more advanced technique is used for the reconfiguration of the integration times. In July 2015, by exploiting again the STSM tool, the prototype was brought to Malta: tests were carried out in buildings, churches, archaeological and geological sites; results were compared with those obtained by using a commercial pulsed system manufactured by IDS Ingegneria dei Sistemi. It is worth pointing out that this was the first time GPR measurements were carried out in Malta, where no GPR systems are available. Finally, in January 2016 the improved prototype was again brought to Malta in order to be used during the experimental sessions of a TU1208 Training School. This is an excellent example of a successful scientific activity where STSM and TS COST networking tools were effectively exploited, the cooperation with industry was of central importance, and a less research-intensive Country was deliberately chosen, to test the improved system. 4. A cheap frequency-modulated continuous-wave GPR prototype was designed and realized by an Italian research team; detailled instructions, describing how to build this radar step-by-step, will be available by the end of the Action. The idea behind this initiative is to support and encourage institutes in less research-intensive Countries, who cannot afford a commercial system, to build their own prototype for training purposes and to start familiarizing with the GPR technique. 5. A new stepped-frequency ground-coupled multi-antenna GPR system for road and bridge inspection was developed by 3d-radar (manufacturer based in Norway) and presented during the GPR 2014 conference as a contribution to COST Action TU1208. The starting point was an analogous commercial system, with air-coupled antennas. For road inspection, air-coupled antennas offer practical advantages over ground-coupled antennas (mainly, the possibility to carry out measurements at higher speeds); moreover, they allow enhanced detection of shallow layers inside the road structure. On the other hand, data from ground-coupled array contain much more details from individual scatterers, making them more suitable to image the granularity of the road base materials and for bridge deck inspection, where reinforcement rebar has to be imaged. Ground-coupled GPR systems also provide higher penetrating depth due to a stronger coupling of energy into the ground. The novel stepped-frequency ground-coupled GPR exploits an array of boomerang-shaped monopole elements. 6. Recommendations for the safety of people and equipment during GPR prospecting were produced. Despite the increasing demand of GPR surveys all over the world, safety matters are rarely considered. The Action put efforts into debating them, with scientists and professionals performing GPR surveys. As an outcome of this activity, a book was published where a series of recommendations are provided. These include general hints, recommendations for surveys carried out in challenging environmental situations, description of risks associated to specific applications, instructions for first medical aid, information about GPR electromagnetic emissions and associated risks, and finally suggestions for a safe use of the equipment and for a respectful interaction with the environment. 7. WG1 contributed to the TU1208 Education Pack, an open-access educational package conceived to teach GPR in University courses. 8. Three Training Schools were organised on radar systems and antennas, in cooperation with the European School of Antennas (ESoA): two editions of the Training School "Future Radar Systems: Radar2020" and a Training School on "UWB Antennas, Technologies and Applications". These courses were held in the Karlsruhe Institute of Technology, in Karlsruhe, Germany. Acknowledgement: The Authors are deeply grateful to COST (European Cooperation in Science and Technology, www.cost.eu), for funding and supporting the COST Action TU1208 "Civil engineering applications of Ground Penetrating Radar" (www.GPRadar.eu).

Signal Coherence Recovery Using Acousto-Optic Fourier Transform Architectures

DTIC Science & Technology

1990-06-14

processing of data in ground- and space-based applications. We have implemented a prototype one-dimensional time-integrating acousto - optic (AO) Fourier...theory of optimum coherence recovery (CR) applicable in computation-limited environments. We have demonstrated direct acousto - optic implementation of CR

Data storage systems technology for the Space Station era

NASA Technical Reports Server (NTRS)

Dalton, John; Mccaleb, Fred; Sos, John; Chesney, James; Howell, David

1987-01-01

The paper presents the results of an internal NASA study to determine if economically feasible data storage solutions are likely to be available to support the ground data transport segment of the Space Station mission. An internal NASA effort to prototype a portion of the required ground data processing system is outlined. It is concluded that the requirements for all ground data storage functions can be met with commercial disk and tape drives assuming conservative technology improvements and that, to meet Space Station data rates with commercial technology, the data will have to be distributed over multiple devices operating in parallel and in a sustained maximum throughput mode.

Geometric error characterization and error budgets. [thematic mapper

NASA Technical Reports Server (NTRS)

Beyer, E.

1982-01-01

Procedures used in characterizing geometric error sources for a spaceborne imaging system are described using the LANDSAT D thematic mapper ground segment processing as the prototype. Software was tested through simulation and is undergoing tests with the operational hardware as part of the prelaunch system evaluation. Geometric accuracy specifications, geometric correction, and control point processing are discussed. Cross track and along track errors are tabulated for the thematic mapper, the spacecraft, and ground processing to show the temporal registration error budget in pixel (42.5 microrad) 90%.

Qualification test results for DOE solar photovoltaic flat panel procurement - PRDA 38

NASA Technical Reports Server (NTRS)

Griffith, J. S.

1980-01-01

Twelve types of prototypes modules for the DOE Photovoltaic Flat Panel Procurement (PRDA 38) were subjected to qualification tests at the Jet Propulsion Laboratory according to a new specification. Environmental exposures were carried out separately and included temperature cycling, humidity, wind simulation, and hail. The most serious problems discovered were reduced insulation resistance to ground and ground continuity of the metal frames, electrical degradation, erratic power readings, and delamination. The electrical and physical characteristics of the newly received modules are also given.

An AI Approach to Ground Station Autonomy for Deep Space Communications

NASA Technical Reports Server (NTRS)

Fisher, Forest; Estlin, Tara; Mutz, Darren; Paal, Leslie; Law, Emily; Stockett, Mike; Golshan, Nasser; Chien, Steve

1998-01-01

This paper describes an architecture for an autonomous deep space tracking station (DS-T). The architecture targets fully automated routine operations encompassing scheduling and resource allocation, antenna and receiver predict generation. track procedure generation from service requests, and closed loop control and error recovery for the station subsystems. This architecture has been validated by the construction of a prototype DS-T station, which has performed a series of demonstrations of autonomous ground station control for downlink services with NASA's Mars Global Surveyor (MGS).

ESD Test Apparatus for Soldering Irons

NASA Technical Reports Server (NTRS)

Sancho, Jose; Esser, Robert

2013-01-01

ESDA (Electrostatic Discharge Association) ESD STM 13.1-2000 requires frequent testing of the voltage leakage from the tip of a soldering iron and the resistance from the tip of the soldering iron to the common point ground. Without this test apparatus, the process is time-consuming and requires several wires, alligator clips, or test probes, as well as additional equipment. Soldering iron tips must be tested for electrostatic discharge risks frequently, and this typically takes a lot of time in setup and testing. This device enables the operator to execute the full test in one minute or less. This innovation is a simple apparatus that plugs into a digital multimeter (DMM) and the Common Point Ground (CPG) reference. It enables the user to perform two of the electrostatic discharge tests required in ESD STM 13.1-2000. The device consists of a small black box with two prongs sticking out of one end, two inputs on the opposite end (one of the inputs is used to connect the reference CPG to the DMM), and a metal tab on one side. Inside the box are wires, several washers of various materials, and assembly hardware (nuts and screws/bolts). The device is a passive electronic component that is plugged into a DMM. The operator sets the DMM to read voltage. The operator places the heated tip of the soldering iron onto the metal tab with a small amount of solder to ensure a complete connection. The voltage is read and recorded. The operator switches the DMM to read resistance. The operator places the heated tip of the soldering iron onto the metal tab with a small amount of solder to ensure a complete connection. The resistance is recorded. If the recorded voltage and resistance are below a number stated in ESDA ESD STM 13.1-2000, the test is considered to pass. The device includes all the necessary wiring internal to its body so the operator does not need to do any independent wiring, except for grounding. It uses a stack of high-thermal-resistance washers to minimize the heat transfer from the soldering iron to the wiring used to measure the resistance and voltages. This minimizes thermal error. The device allows very rapid execution of a test that is performed frequently.

Microgravity Investigation of Crew Reactions in 0-G (MICR0-G): Ground-Based Development Effort

NASA Technical Reports Server (NTRS)

Newman, Dava J.

2002-01-01

This report describes the technology development of an advanced load sensor ground-based prototype and details the preliminary tests in microgravity during parabolic flights. The research effort is entitled, the Microgravity Investigation and Crew Reactions in 0-G (MICR0-G), a ground-based research effort funded by the National Aeronautics and Space Administration (NASA). The MICR0-G project was a follow-on to the Enhanced Dynamic Load Sensors (EDLS) spaceflight experiment flown on the Russian Space Station Mir. The technology development of the advanced load sensor prototype has been carried out by the Massachusetts Institute of Technology (MIT), with collaboration from Politecnico di Milano University and the Italian Space Agency (ASI). The key hardware of the advanced sensor prototype is a set of two types of load sensors - a hand-hold and foot restraints - similar in appearance to the mobility aids found in the Space Shuttle orbiter to assist the crew in moving inside the spacecraft, but able to measure the applied forces and moments about the x-, y-, and z- axes. The aim of Chapter 1 is to give a brief overview of the report contents. The first section summarizes the previous research efforts on astronaut-induced loads in microgravity. The second section provides information on the MICR0-G research project and the technology development work conducted at MIT. Section 1.3 details the motivation for designing a new generation of load sensors and describes the main enhancements and contributions of the MICR0-G advanced load sensors system compared to the EDLS system. Finally, the last section presents the outline of the report.

Field Testing of a Prototype Filter System for the Removal of the Human Pathogen Giardia intestinales from Ground Water

NASA Astrophysics Data System (ADS)

Rust, C.; Schulze-Makuch, D.; Bowman, R.; Meier, D.

2005-12-01

Pathogenic bacteria, viruses, and protozoans tend to be negatively charged in the pH range of most ground waters. Thus, naturally occurring and modified materials such as surfactant-modified zeolites (SMZ), which have net positive surface charges and hydrophobic properties, are suitable as barriers to impede pathogen migration in aquifer systems. In our experiments SMZ has been used to remove E. coli and the bacteriophage MS-2 from sewage water with a high success rate ( E. coli 100%, MS-2 > 90%). Testing was conducted both in the laboratory and the field. Laboratory experiments were conducted to test the removal efficiency of SMZ for Giardia intestinales using the Giardia cysts and microsphere analogs. The SMZ was effective at removing Giardia intestinales cysts from the groundwater, but removal rates were not as high as for bacteria and viruses in the earlier experiments. The removal efficiency varied with the particular formulation of the SMZ used. The most effective SMZ formulation is being further tested at our field site using water amended with microspheres to simulate Giardia behavior. The field site is an existing multiple well site at the University of Idaho in Moscow. The wells are completed in the Lolo Basalt Formation; a highly heterogeneous and anisotropic fractured basalt aquifer system typical of the subsurface of most of eastern Washington and northeastern Oregon. The SMZ pathogen filter is installed directly in the well bore and the concentrations of microsphere-amended ground water are measured before and after filtration. Pumping over an extended period is continuing in order to test the lifetime of our prototype filter system. Our tests and results are targeted at developing a prototype filter system for removing a multitude of human pathogens in drinking water.

A new deflection technique applied to an existing scheme of electrostatic accelerator for high energy neutral beam injection in fusion reactor devices

NASA Astrophysics Data System (ADS)

Pilan, N.; Antoni, V.; De Lorenzi, A.; Chitarin, G.; Veltri, P.; Sartori, E.

2016-02-01

A scheme of a neutral beam injector (NBI), based on electrostatic acceleration and magneto-static deflection of negative ions, is proposed and analyzed in terms of feasibility and performance. The scheme is based on the deflection of a high energy (2 MeV) and high current (some tens of amperes) negative ion beam by a large magnetic deflector placed between the Beam Source (BS) and the neutralizer. This scheme has the potential of solving two key issues, which at present limit the applicability of a NBI to a fusion reactor: the maximum achievable acceleration voltage and the direct exposure of the BS to the flux of neutrons and radiation coming from the fusion reactor. In order to solve these two issues, a magnetic deflector is proposed to screen the BS from direct exposure to radiation and neutrons so that the voltage insulation between the electrostatic accelerator and the grounded vessel can be enhanced by using compressed SF6 instead of vacuum so that the negative ions can be accelerated at energies higher than 1 MeV. By solving the beam transport with different magnetic deflector properties, an optimum scheme has been found which is shown to be effective to guarantee both the steering effect and the beam aiming.

A new deflection technique applied to an existing scheme of electrostatic accelerator for high energy neutral beam injection in fusion reactor devices.

PubMed

Pilan, N; Antoni, V; De Lorenzi, A; Chitarin, G; Veltri, P; Sartori, E

2016-02-01

A scheme of a neutral beam injector (NBI), based on electrostatic acceleration and magneto-static deflection of negative ions, is proposed and analyzed in terms of feasibility and performance. The scheme is based on the deflection of a high energy (2 MeV) and high current (some tens of amperes) negative ion beam by a large magnetic deflector placed between the Beam Source (BS) and the neutralizer. This scheme has the potential of solving two key issues, which at present limit the applicability of a NBI to a fusion reactor: the maximum achievable acceleration voltage and the direct exposure of the BS to the flux of neutrons and radiation coming from the fusion reactor. In order to solve these two issues, a magnetic deflector is proposed to screen the BS from direct exposure to radiation and neutrons so that the voltage insulation between the electrostatic accelerator and the grounded vessel can be enhanced by using compressed SF6 instead of vacuum so that the negative ions can be accelerated at energies higher than 1 MeV. By solving the beam transport with different magnetic deflector properties, an optimum scheme has been found which is shown to be effective to guarantee both the steering effect and the beam aiming.

A DIM model for sodium cluster-ions interacting with a charged conducting sphere

NASA Astrophysics Data System (ADS)

Kuntz, P. J.

A diatomics-in-molecules (DIM) model for the energy, shape and charge distribution of metal cluster ions in the presence of a charged insulated conducting sphere is presented. The electrostatic interaction between the sphere and the cluster-ion is introduced in a self-consistent manner which allows the sphere to be polarized by the ion and the ion by the sphere. This interaction appears in the diagonal elements of the model Hamiltonian matrix in such a way that the lowest eigenvalue includes the correct electrostatic energy for the charge distribution in the ground state. The model is applied to the calculation of fusion barriers for Na+2 and Na+3 ions. When both the charge distribution and the geometric configuration of the cluster-ion are allowed to relax freely, the energy as a function of distance from the sphere is nearly the same as that calculated from the electrostatic energy alone, which implies that details of the molecular structure of the cluster-ion can be neglected in calculating fusion barriers from charge polarization alone. That the fusion barriers lie sufficiently far away from the sphere so that the molecule does not dissociate under the influence of the Coulomb interaction confirms that it is meaningful to speak of two separate entities at the barrier position.

Design and Testing of a Lyophilizer for Water Recovery from Solid Waste

NASA Technical Reports Server (NTRS)

Litwiller, Eric; Fisher, John; Flynn, Michael

2005-01-01

Mixed liquid/solid wastes, including feces, water processor effluents, and food waste, can be lyophilized (freeze-dried) to recover the water they contain and stabilize the solids remain. Previous research has demonstrated the potential benefits of using thermoelectric heat pumps to build a lyophilizer for processing waste in microgravity. These results were used to build a working prototype suitable for ground-based human testing. This paper describes the prototype design and presents the results of functional and performance tests. Equivalent system mass parameters are calculated, and practical issues such as sanitary waste handling in microgravity are addressed.

Characterization of the Electrostatic Environment of Launchers

NASA Astrophysics Data System (ADS)

Soyah, Jamila; Mantion, Pascal; Herlem, Yannick

2016-05-01

The purpose of this study was to update knowledge in characterization of the electrostatic environment of launchers in order to be able to propose reductions of design constraints.The first part of this study showed that flashover discharges are the most energetic discharges likely to occur on a launcher. They are mostly due to accumulations of charges by triboelectricity on the external surface of the launcher while flying through clouds containing a lot of small solid particles.Actually flashover discharges are mitigated by limiting the surface's resistance of dielectric materials such as thermal protection set on the external skin of the launcher, thanks to antistatic paints that avoid significant accumulations of charges.But this specified limitation leads to a lot of non- conformances during production phases and, as a result, this leads to additional costs and delays in launches campaigns. That is why on-ground tests have been defined in order to assess the accessibility of a relaxation of those specifications, which would reduce non-conformances.On-ground tests have been carried out, in the second part, on samples of thermal protections covered with antistatic paints with different degraded values of surface resistance. These tests aimed at checking in which conditions a surface discharge can occur in order to deduce a relationship between characteristics of the samples (surface resistance, half-discharge time) and the occurrence of a surface discharge, at ambient pressure and at low pressure.In the third part, in-flight experiments have been defined in order to confirm some hypotheses considered in the study and to assess some parameters in a more accurate way like the incoming charges density per surface unit or the voltage between stages when they get separated, in order to assess more accurately whether the unwinding equalization wire dedicated to maintain the electrostatic balance between stages is necessary or not.

The phase behavior of cationic lipid-DNA complexes.

PubMed Central

May, S; Harries, D; Ben-Shaul, A

2000-01-01

We present a theoretical analysis of the phase behavior of solutions containing DNA, cationic lipids, and nonionic (helper) lipids. Our model allows for five possible structures, treated as incompressible macroscopic phases: two lipid-DNA composite (lipoplex) phases, namely, the lamellar (L(alpha)(C)) and hexagonal (H(II)(C)) complexes; two binary (cationic/neutral) lipid phases, that is, the bilayer (L(alpha)) and inverse-hexagonal (H(II)) structures, and uncomplexed DNA. The free energy of the four lipid-containing phases is expressed as a sum of composition-dependent electrostatic, elastic, and mixing terms. The electrostatic free energies of all phases are calculated based on Poisson-Boltzmann theory. The phase diagram of the system is evaluated by minimizing the total free energy of the three-component mixture with respect to all the compositional degrees of freedom. We show that the phase behavior, in particular the preferred lipid-DNA complex geometry, is governed by a subtle interplay between the electrostatic, elastic, and mixing terms, which depend, in turn, on the lipid composition and lipid/DNA ratio. Detailed calculations are presented for three prototypical systems, exhibiting markedly different phase behaviors. The simplest mixture corresponds to a rigid planar membrane as the lipid source, in which case, only lamellar complexes appear in solution. When the membranes are "soft" (i.e., low bending modulus) the system exhibits the formation of both lamellar and hexagonal complexes, sometimes coexisting with each other, and with pure lipid or DNA phases. The last system corresponds to a lipid mixture involving helper lipids with strong propensity toward the inverse-hexagonal phase. Here, again, the phase diagram is rather complex, revealing a multitude of phase transitions and coexistences. Lamellar and hexagonal complexes appear, sometimes together, in different regions of the phase diagram. PMID:10733951

Electrostatic Accelerometer for the Gravity Recovery and Climate Experiment Follow-On Mission (GRACE FO)

NASA Astrophysics Data System (ADS)

Perrot, Eddy; Boulanger, Damien; Christophe, Bruno; Foulon, Bernard; Liorzou, Françoise; Lebat, Vincent

2014-05-01

The GRACE FO mission, led by the JPL (Jet Propulsion Laboratory), is an Earth-orbiting gravity mission, continuation of the GRACE mission, that will produce an accurate model of the Earth's gravity field variation providing global climatic data during five year at least. The mission involves two satellites in a loosely controlled tandem formation, with a micro-wave link, and optionally a laser link, measuring the inter-satellites distance variation. Non-uniformities in the distribution of the Earth's mass cause the distance between the two satellites to vary. This variation is measured to recover gravity, after subtracting the non-gravitational contributors, as the residual drag. ONERA (the French Aerospace Lab) is developing, manufacturing and testing electrostatic accelerometers measuring this residual drag applied on the satellites. The accelerometer is composed of two main parts: the Sensor Unit (including the Sensor Unit Mechanics - SUM - and the Front-End Electronic Unit - FEEU) and the Interface Control Unit. In the Accelerometer Core, located in the Sensor Unit Mechanics, the proof mass is levitated and maintained in a center of an electrode cage by electrostatic forces. Thus, any drag acceleration applied on the satellite involves a variation on the servo-controlled electrostatic suspension of the mass. The voltage on the electrodes providing this electrostatic force is the measurement output of the accelerometer. The Preliminary Design Review was achieved successfully on November 2013. The FEEU Engineering Model is under test. Preliminary results on electronic unit will be compared with the expected performance. The integration of the SUM Engineering Model and the first ground levitation of the proof-mass will be presented. The impact of the accelerometer defaults (geometry, electronic and parasitic forces) leads to bias, misalignment and scale factor error, non-linearity and noise. Some of these accelerometer defaults are characterized by tests with micro-gravity pendulum bench and with drops in ZARM catapult. The post-processing needed to achieve the performance, in particular with regards to the temperature stability, will be explained.

Development of a prototype two-phase thermal bus system for Space Station

NASA Technical Reports Server (NTRS)

Myron, D. L.; Parish, R. C.

1987-01-01

This paper describes the basic elements of a pumped two-phase ammonia thermal control system designed for microgravity environments, the development of the concept into a Space Station flight design, and design details of the prototype to be ground-tested in the Johnson Space Center (JSC) Thermal Test Bed. The basic system concept is one of forced-flow heat transport through interface heat exchangers with anhydrous ammonia being pumped by a device expressly designed for two-phase fluid management in reduced gravity. Control of saturation conditions, and thus system interface temperatures, is accomplished with a single central pressure regulating valve. Flow control and liquid inventory are controlled by passive, nonelectromechanical devices. Use of these simple control elements results in minimal computer controls and high system reliability. Building on the basic system concept, a brief overview of a potential Space Station flight design is given. Primary verification of the system concept will involve testing at JSC of a 25-kW ground test article currently in fabrication.

Galileo Galilei (GG): the space mission and the prototype

NASA Astrophysics Data System (ADS)

Nobili, A.

"GALILEO GALILEI (GG)" is a proposal to fly a small satellite in low Earth orbit aiming to test the Equivalence Principle of Galileo, Newton and Einstein to 1 part in 1017 at room temperature. Ground tests carried out with artificial test bodies on rotating torsion balances, and tests with celestial bodies based on Lunar Laser Ranging data, have found no violation to about 1 part in 1013 . Competing space pro jects are SCOPE (also at room temperature) aiming to 1 part in 1015 , and STEP (at very low temperature) aiming to 1 part in 1018 . GG is characterized by fast rotation and by the possibility to perform a full scale test on the ground. This talk will present the main features of the GG design, as compared to STEP and SCOPE, and report the experimental results obtained with the first and the second generation laboratory prototypes (natural frequencies, quality factor, stability, sensitivity). Interested scientists are welcome to visit the GG webpage at http://eotvos.dm.unipi.it/nobili.

Umbilical Connect Techniques Improvement-Technology Study

NASA Technical Reports Server (NTRS)

Valkema, Donald C.

1972-01-01

The objective of this study was to develop concepts, specifications, designs, techniques, and procedures capable of significantly reducing the time required to connect and verify umbilicals for ground services to the space shuttle. The desired goal was to reduce the current time requirement of several shifts for the Saturn 5/Apollo to an elapsed time of less than one hour to connect and verify all of the space shuttle ground service umbilicals. The study was conducted in four phases: (1) literature and hardware examination, (2) concept development, (3) concept evaluation and tradeoff analysis, and (4) selected concept design. The final product of this study was a detail design of a rise-off disconnect panel prototype test specimen for a LO2/LH2 booster (or an external oxygen/hydrogen tank for an orbiter), a detail design of a swing-arm mounted preflight umbilical carrier prototype test specimen, and a part 1 specification for the umbilical connect and verification design for the vehicles as defined in the space shuttle program.

A Saturn launched X-ray astronomy experiment. Volume 1: S-027

NASA Technical Reports Server (NTRS)

1971-01-01

The S-027 X-Ray Astronomy Experiment originally proposed in early 1966, was developed to detect X-rays in the 2 keV to 10 keV range. Both a prototype unit and flight unit were constructed with the prototype unit also serving as the engineering model, the qualification test unit, and after refurbishment, as the back-up flight unit. Two Ground Support Equipment consoles were built to verify the experiment operation. A photograph of one experiment package with its Ground Support Equipment is shown. The S-027 experiment was scheduled for launch in 1968/69 and although both units were completed and tested to the extent that either would be ready for the scheduled launch, delays in the space program resulted in a launch date slip of several years. When the 1968/69 launch delay became official, provisions were made for storage of the two experiment packages at SCI Electronics in Huntsville, Alabama until a new launch date could be established.

Controlled waveguide coupling for photon emission from colloidal PbS quantum dot using tunable microcavity made of optical polymer and silicon

NASA Astrophysics Data System (ADS)

Nozaka, Takahiro; Mukai, Kohki

2016-04-01

A tunable microcavity device composed of optical polymer and Si with a colloidal quantum dot (QD) is proposed as a single-photon source for planar optical circuit. Cavity size is controlled by electrostatic micromachine behavior with the air bridge structure to tune timing of photon injection into optical waveguide from QD. Three-dimensional positioning of a QD in the cavity structure is available using a nanohole on Si processed by scanning probe microscope lithography. We fabricated the prototype microcavity with PbS-QD-mixed polymenthyl methacrylate on a SOI (semiconductor-on-insulator) substrate to show the tunability of cavity size as the shift of emission peak wavelength of QD ensemble.

A hybrid electronically scanned pressure module for cryogenic environments

NASA Technical Reports Server (NTRS)

Chapman, J. J.; Hopson, P., Jr.; Kruse, N.

1995-01-01

Pressure is one of the most important parameters measured when testing models in wind tunnels. For models tested in the cryogenic environment of the National Transonic Facility at NASA Langley Research Center, the technique of utilizing commercially available multichannel pressure modules inside the models is difficult due to the small internal volume of the models and the requirement of keeping the pressure transducer modules within an acceptable temperature range well above the -173 degrees C tunnel temperature. A prototype multichannel pressure transducer module has been designed and fabricated with stable, repeatable sensors and materials optimized for reliable performance in the cryogenic environment. The module has 16 single crystal silicon piezoresistive pressure sensors electrostatically bonded to a metalized Pyrex substrate for sensing the wind tunnel model pressures. An integral temperature sensor mounted on each silicon micromachined pressure sensor senses real-time temperature fluctuations to within 0.1 degrees C to correct for thermally induced non-random sensor drift. The data presented here are from a prototype sensor module tested in the 0.3 M cryogenic tunnel and thermal equilibrium conditions in an environmental chamber which approximates the thermal environment (-173 degrees C to +60 degrees C) of the National Transonic Facility.

Electromagnetic Compatibility of Transcutaneous Energy Transmission Systemfor Totally Implantable Artificial Heart

NASA Astrophysics Data System (ADS)

Shiba, Kenji; Koshiji, Kohji

Transcutaneous Energy Transmission (TET) is one way of providing the energy needed to power a totally implantable artificial heart (TIAH). In the present study, an externally coupled TET system was implanted in a prototype human phantom to evaluate emission and immunity. In the emission evaluation, measurements were conducted based on CISPR Pub.11 and VDE 0871 standards, while immunity tests were based on the standards of the IEC 61000-4 series. The magnetic field of the radiated emission was measured using a loop antenna. At 0.1[MHz], we found the greatest magnetic field of 47.8 [dBμA/m], somewhat less than CISPR’s upper limit of 54 [dBμA/m]. For the conducted emission, by installing a noise filter and ferrite beads in the input section of the DC-power supply, conducted emission could be kept within the allowable limits of CISPR Pub.11 and VDE 0871. Finally, the immunity tests against radiated and conducted emission, electrostatic discharge and voltage fluctuation proved that the prototype could withstand the maximum level of disturbance. These results confirmed that the TET system implanted in a human phantom could, through modification, meet the emission and immunity standards.

A flexible electrostatic kinetic energy harvester based on electret films of electrospun nanofibers

NASA Astrophysics Data System (ADS)

Lu, Y.; Capo-Chichi, M.; Leprince-Wang, Y.; Basset, P.

2018-01-01

This paper reports a paper-based electrostatic kinetic energy harvester (e-KEH) implementing multilayered electret films based on electrospun nanofibrous material. It is the first time that a fully flexible electret-based e-KEH is reported. The proposed electret, PVDF-PTFD nanofibrous covered by Parylene C, has a faster stabilization of surface potential than a planar thin film of Parylene C, and a higher stability of charge storage. With a maximum force of 0.5 N and a 3-layer electret, the device capacitance increases from 25 to 100 pF during a pressing operation. Working with the optimal resistive load of 16 MΩ, the device pressed manually delivers a peak instantaneous power up to 45.6 μW and an average energy of 54 nJ/stroke, corresponding to a peak instantaneous power density of 7.3 μW cm-2 and an average energy density of 8.6 nJ cm-2/stroke. Within 450 manual strokes, a 10 nF capacitor is charged up to 8.5 V by the prototype through a full-wave diode bridge. On a 1 μF capacitor, the energy delivery of 9.9 nJ/stroke has been obtained with a 10 Hz pressing movement excited by a vibrator with a maximum force of 0.5 N.

Estimating AADT from combined air photos and ground based data : system design, prototyping, and testing.

DOT National Transportation Integrated Search

2009-09-15

Average annual daily traffic (AADT) is perhaps the most fundamental measure of traffic flow. The data used to produce AADT estimates are largely collected by in-highway traffic counters operated by traffic monitoring crews who must cover thousands of...

Improved Design of Tunnel Supports : Volume 5 : Empirical Methods in Rock Tunneling -- Review and Recommendations

DOT National Transportation Integrated Search

1980-06-01

Volume 5 evaluates empirical methods in tunneling. Empirical methods that avoid the use of an explicit model by relating ground conditions to observed prototype behavior have played a major role in tunnel design. The main objective of this volume is ...

Performance Evaluation of a Prototyped Wireless Ground Sensor Network

DTIC Science & Technology

2005-03-01

the network was capable of dynamic adaptation to failure and degradation. 14. SUBJECT TERMS: Wireless Sensor Network , Unmanned Sensor, Unattended...2 H. WIRELESS SENSOR NETWORKS .................................................................... 3...zation, and network traffic. The evaluated scenarios included outdoor, urban and indoor environments. The characteristics of wireless sensor networks , types

Re-Engineering of the Hubble Space Telescope (HST) to Reduce Operational Costs

NASA Technical Reports Server (NTRS)

Garvis, Michael; Dougherty, Andrew; Whittier, Wallace

1996-01-01

Satellite telemetry processing onboard the Hubble Space Telescope (HST) is carried out using dedicated software and hardware. The current ground system is expensive to operate and maintain. The mandate to reduce satellite ground system operations and maintenance costs by the year 2000 led NASA to upgrade the command and control systems in order to improve the data processing capabilities, reduce operator experience levels and increase system standardization. As a result, a command and control system product development team was formed to redesign and develop the HST ground system. The command and control system ground system development consists of six elements. The results of the prototyping phase carried out for the following of these elements are presented: the front end processor; middleware, and the graphical user interface.

Expert system decision support for low-cost launch vehicle operations

NASA Technical Reports Server (NTRS)

Szatkowski, G. P.; Levin, Barry E.

1991-01-01

Progress in assessing the feasibility, benefits, and risks associated with AI expert systems applied to low cost expendable launch vehicle systems is described. Part one identified potential application areas in vehicle operations and on-board functions, assessed measures of cost benefit, and identified key technologies to aid in the implementation of decision support systems in this environment. Part two of the program began the development of prototypes to demonstrate real-time vehicle checkout with controller and diagnostic/analysis intelligent systems and to gather true measures of cost savings vs. conventional software, verification and validation requirements, and maintainability improvement. The main objective of the expert advanced development projects was to provide a robust intelligent system for control/analysis that must be performed within a specified real-time window in order to meet the demands of the given application. The efforts to develop the two prototypes are described. Prime emphasis was on a controller expert system to show real-time performance in a cryogenic propellant loading application and safety validation implementation of this system experimentally, using commercial-off-the-shelf software tools and object oriented programming techniques. This smart ground support equipment prototype is based in C with imbedded expert system rules written in the CLIPS protocol. The relational database, ORACLE, provides non-real-time data support. The second demonstration develops the vehicle/ground intelligent automation concept, from phase one, to show cooperation between multiple expert systems. This automated test conductor (ATC) prototype utilizes a knowledge-bus approach for intelligent information processing by use of virtual sensors and blackboards to solve complex problems. It incorporates distributed processing of real-time data and object-oriented techniques for command, configuration control, and auto-code generation.

Development of ultrasonic electrostatic microjets for distributed propulsion and microflight

NASA Astrophysics Data System (ADS)

Amirparviz, Babak

This dissertation details the first attempt to design and fabricate a distributed micro propulsion system based on acoustic streaming. A novel micro propulsion method is suggested by combining Helmholtz resonance, acoustic streaming and flow entrainment and thrust augmentation. In this method, oscillatory motion of an electrostatically actuated diaphragm creates a high frequency acoustic field inside the cavity of a Helmholtz resonator. The initial fluid motion velocity is amplified by the Helmholtz resonator structure and creates a jet flow at the exit nozzle. Acoustic streaming is the phenomenon responsible for primary jet stream creation. Primary jets produced by a few resonators can be combined in an ejector configuration to induce flow entrainment and thrust augmentation. Basic governing equations for the electrostatic actuator, deformation of the diaphragm and the fluid flow inside the resonator are derived. These equations are linearized and used to derive an equivalent electrical circuit model for the operation of the device. Numerical solution of the governing equations and simulation of the circuit model are used to predict the performance of the experimental systems. Thrust values as high as 30.3muN are expected per resonator. A micro machined electrostatically-driven high frequency Helmholtz resonator prototype is designed and fabricated. A new micro fabrication technique is developed for bulk micromachining and in particular fabrication of the resonator. Geometric stops for wet anisotropic etching of silicon are introduced for the fist time for structure formation. Arrays of high frequency (>60kHz) micro Helmholtz resonators are fabricated. In one sample more than 1000 resonators cover the surface of a four-inch silicon wafer and in effect convert it to a distributed propulsion system. A high yield (>85%) micro fabrication process is presented for realization of this propulsion system taking advantage of newly developed deep glass micromachining and lithography on thin (15mum) silicon methods. Extensive test and characterization are performed on the micro jets using current frequency component analysis, laser interferometry, acoustic measurements, hot-wire anemometers, video particle imaging and load cells. The occurrence of acoustic streaming at jet nozzles is verified and flow velocities exceeding 1m/s are measured at the 15mum x 330mum jet exit nozzle.

Net current control device. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fugate, D.; Cooper, J.H.

1998-11-01

Net currents generally result in elevated magnetic fields because the alternate paths are distant from the circuit conductors. Investigations have shown that one of the primary sources of power frequency magnetic fields in residential buildings is currents that return to their source via paths other than the neutral conductors. As part of EPRI`s Magnetic Field Shielding Project, ferromagnetic devices, called net current control (NCC) devices, were developed and tested for use in reducing net currents on electric power cables and the resulting magnetic fields. Applied to a residential service drop, an NCC device reduces net current by forcing current offmore » local non-utility ground paths, and back onto the neutral conductor. Circuit models and basic design equations for the NCC concept were developed, and proof-of-principles tests were carried out on an actual residence with cooperation from the local utility. After proving the basic concepts, three prototype NCC devices were built and tested on a simulated neighborhood power system. Additional prototypes were built for testing by interested EPRI utility members. Results have shown that the NCC prototypes installed on residential service drops reduce net currents to milliampere levels with compromising the safety of the ground system. Although the focus was on application to residential service cables, the NCC concept is applicable to single-phase and three-phase distribution systems as well.« less

Variable energy, high flux, ground-state atomic oxygen source

NASA Technical Reports Server (NTRS)

Chutjian, Ara (Inventor); Orient, Otto J. (Inventor)

1987-01-01

A variable energy, high flux atomic oxygen source is described which is comprised of a means for producing a high density beam of molecules which will emit O(-) ions when bombarded with electrons; a means of producing a high current stream of electrons at a low energy level passing through the high density beam of molecules to produce a combined stream of electrons and O(-) ions; means for accelerating the combined stream to a desired energy level; means for producing an intense magnetic field to confine the electrons and O(-) ions; means for directing a multiple pass laser beam through the combined stream to strip off the excess electrons from a plurality of the O(-) ions to produce ground-state O atoms within the combined stream; electrostatic deflection means for deflecting the path of the O(-) ions and the electrons in the combined stream; and, means for stopping the O(-) ions and the electrons and for allowing only the ground-state O atoms to continue as the source of the atoms of interest. The method and apparatus are also adaptable for producing other ground-state atoms and/or molecules.

Microwave-based navigation of femtosatellites using on-off keying

NASA Astrophysics Data System (ADS)

Kamte, Namrata Jagdish

The objective of this research is to validate that a custom-built microchip-scale satellite transmitting a signal modulated with a Pseudo Random Noise code using On-Off Keying, can be tracked. The weak GPS satellite signal is modulated with a Pseudo Random Noise (PRN) code that provides a mathematical gain. Our signal is modulated with the same PRN code using On-Off Keying (OOK) unlike Phase Shift Keying used in GPS satellites. Our goal is to obtain timing and positioning information from the microchip-scale satellite via a ground station using the concepts of PRN encoding and the OOK modulation technique. Decimeter scale satellites, with a mass of 2--6 kilograms, referred to as picosatellites, have been tracked successfully by ground stations. The microchip-scale satellite, called the femtosatellite is smaller with even less mass, at most 100 grams. At this size the satellite can take advantage of small-scale physics to perform maneuver, such as solar pressure, which only slightly perturb large spacecraft. Additionally, the reduced size decreases the cost of launch as compared to the picosatellites. A swarm of such femtosatellites can serve as environmental probes, interplanetary chemists or in-orbit inspectors of the parent spacecraft. In May 2011, NASA's last space shuttle mission STS-134 carried femtosatellites developed by Cornell researchers called "Sprites". The sprites were deployed from the International Space Station but ground stations on Earth failed to track them. In an effort to develop an alternative femtosatellite design, we have built our own femtosatellite prototype. Our femtosatellite prototype contains the AVR microcontroller on an Arduino board. This assembly is connected to a radio transmitter and a custom antenna transmitting a 433 Mhz radio frequency signal. The prototype transmits a PRN code modulated onto the signal using OOK. Our ground station consists of a Universal Software Radio Peripheral (USRP) with a custom antenna for reception of the 433 MHz signal. The USRP is driven by an open source software-defined radio application called GNU Radio. The required components of the signal are extracted from GNU Radio and processed in order to plot the received data. Benchtop testing of these OOK signals has yielded a reception sensitivity of upto 1 microsecond, which translates into a ranging capability similar to that of GPS satellites. We have correlated the received and replica PRN sequences and demonstrated that they match. The correlation can be used to obtain the identity and position of the femtosatellite prototype. This demonstrates the ability to track a femtosatellite signal that is lower than ambient noise, just like the signals broadcast from GPS satellites. Further, we have performed a system analysis and recognized key system behavioral problems. Thus we have determinately developed an optimum femtosatellite prototype and designed a novel positioning signal, providing a stepping- stone in the journey of successful femtosatellite communication.

The protection of photovoltaic power systems from lightning

NASA Astrophysics Data System (ADS)

Rogers, C. B.

Lightning protection techniques at nine prototype photovoltaic power system sites with outputs from 18-225 kW are described. Noting that protection schemes are devised to fit isokeraunic data for specific sites, grounding is cited as a common feature for all systems. The grounds are, in separate instances, connected to junction boxes, frames of the solar cell panels, lead from the dc center, from the dc negative terminal, from the frames and equipment, at the array turntable, or from the building rebar frames. The dc power cables are protected by either metal conduit, metal conduit ground wire, direct burial, by rigid metal conduit, ground conductors, or by ground conductors at the ends of the conduit run. Costs run from 0.01-0.28$/W, with all the systems outfitted with bypass and blocking diodes. Direct stroke protection is viewed as less important than isokeraunic data.

Technology Transfer Opportunities: Automated Ground-Water Monitoring

USGS Publications Warehouse

Smith, Kirk P.; Granato, Gregory E.

1997-01-01

Introduction A new automated ground-water monitoring system developed by the U.S. Geological Survey (USGS) measures and records values of selected water-quality properties and constituents using protocols approved for manual sampling. Prototypes using the automated process have demonstrated the ability to increase the quantity and quality of data collected and have shown the potential for reducing labor and material costs for ground-water quality data collection. Automation of water-quality monitoring systems in the field, in laboratories, and in industry have increased data density and utility while reducing operating costs. Uses for an automated ground-water monitoring system include, (but are not limited to) monitoring ground-water quality for research, monitoring known or potential contaminant sites, such as near landfills, underground storage tanks, or other facilities where potential contaminants are stored, and as an early warning system monitoring groundwater quality near public water-supply wells.

Space/ground systems as cooperating agents

NASA Technical Reports Server (NTRS)

Grant, T. J.

1994-01-01

Within NASA and the European Space Agency (ESA) it is agreed that autonomy is an important goal for the design of future spacecraft and that this requires on-board artificial intelligence. NASA emphasizes deep space and planetary rover missions, while ESA considers on-board autonomy as an enabling technology for missions that must cope with imperfect communications. ESA's attention is on the space/ground system. A major issue is the optimal distribution of intelligent functions within the space/ground system. This paper describes the multi-agent architecture for space/ground systems (MAASGS) which would enable this issue to be investigated. A MAASGS agent may model a complete spacecraft, a spacecraft subsystem or payload, a ground segment, a spacecraft control system, a human operator, or an environment. The MAASGS architecture has evolved through a series of prototypes. The paper recommends that the MAASGS architecture should be implemented in the operational Dutch Utilization Center.

Conductive Composites Made Less Expensively

NASA Technical Reports Server (NTRS)

Gaier, James R.

2005-01-01

The use of electrically conductive composite structures for electrostatic dissipation, electromagnetic interference shielding, and ground return planes could save between 30 and 90 percent of the mass of the structure, in comparison to aluminum. One strategy that has been shown to make conducting composites effectively uses intercalated graphite fiber as the reinforcement. Intercalation--the insertion of guest atoms or molecules between the graphene planes--can lower the electrical resistivity of graphite fibers by as much as a factor of 10, without sacrificing mechanical or thermal properties.

A Public Health Approach to Evaluating the Significance of Air Ions

DTIC Science & Technology

1997-05-22

Benjamin Bradshaw and Frank Moore. I would also like to recognize Dr.’s John Herbold, Alphonse Holguin and Jimmy Perkins who acting as sounding boards for...if these mechanisms are, in fact, present and whether they may be linked at all to air ions action.75 The last item put forth by Kellog relates to the...positive ions. Kellog also points out that the recognized necessity for grounding experimental subjects 26’ 49 37 would also not be valid if electrostatic

Electromagnetic emission experiences using electric propulsion systems: A survey

NASA Technical Reports Server (NTRS)

Sovey, James S.; Zana, Lynnette M.; Knowles, Steven C.

1987-01-01

As electric propulsion systems become ready to integrate with spacecraft systems, the impact of propulsion system radiated emissions are of significant interest. Radiated emissions from electromagnetic, electrostatic, and electrothermal systems have been characterized and results synopsized from the literature describing 21 space flight programs. Electromagnetic radiated emission results from ground tests and flight experiences are presented with particular attention paid to the performance of spacecraft subsystems and payloads during thruster operations. The impacts to transmission of radio frequency signals through plasma plumes are also reviewed.

Ensuring a reliable satellite

NASA Astrophysics Data System (ADS)

Johnson, Charles E.; Persinger, Randy R.; Lemon, James J.; Volkert, Keith J.

Comprehensive testing and monitoring approaches have been formulated and implemented for Intelsat VI, which is the largest commercial satellite in service. An account is given of the ground test program from unit level through launch site activities, giving attention to the test data handling system. Test methods unique to Intelsat VI encompass near-field anechoic chamber antenna measurements, offloading 1-g deployment of solar cell and deflector antennas, and electrostatic discharge measurements. The problems accruing to the sheer size of this spacecraft are stressed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kleinert, J.; Haimberger, C.; Zabawa, P. J.

We describe the realization of a dc electric-field trap for ultracold polar molecules, the thin-wire electrostatic trap (TWIST). The thin wires that form the electrodes of the TWIST allow us to superimpose the trap onto a magneto-optical trap (MOT). In our experiment, ultracold polar NaCs molecules in their electronic ground state are created in the MOT via photoassociation, achieving a continuous accumulation in the TWIST of molecules in low-field seeking states. Initial measurements show that the TWIST trap lifetime is limited only by the background pressure in the chamber.

Usage of Fault Detection Isolation & Recovery (FDIR) in Constellation (CxP) Launch Operations

NASA Technical Reports Server (NTRS)

Ferrell, Rob; Lewis, Mark; Perotti, Jose; Oostdyk, Rebecca; Spirkovska, Lilly; Hall, David; Brown, Barbara

2010-01-01

This paper will explore the usage of Fault Detection Isolation & Recovery (FDIR) in the Constellation Exploration Program (CxP), in particular Launch Operations at Kennedy Space Center (KSC). NASA's Exploration Technology Development Program (ETDP) is currently funding a project that is developing a prototype FDIR to demonstrate the feasibility of incorporating FDIR into the CxP Ground Operations Launch Control System (LCS). An architecture that supports multiple FDIR tools has been formulated that will support integration into the CxP Ground Operation's Launch Control System (LCS). In addition, tools have been selected that provide fault detection, fault isolation, and anomaly detection along with integration between Flight and Ground elements.

JPL space station telerobotic engineering prototype development FY 91 status/achievements

NASA Technical Reports Server (NTRS)

Zimmerman, Wayne

1991-01-01

The topics covered are presented in view graph form and include: (1) streamlining intravehicular activity (IVA) teleoperation activities on the Space Station Freedom (SSF); (2) enhancing SSF utilization during the man-tended phase; (3) telerobotic ground remote operations (TGRO); and (4) advanced telerobotics system technology (shared control).

Environmental Study Area Prototype, Idea Sketch No. 4.

ERIC Educational Resources Information Center

Pueblo Regional Planning Commission, CO.

Development of an environmental study area in conjunction with a school landscaping project is outlined in this model. The Pueblo (Colorado) Regional Planning Commission and the Pueblo Beautiful Association determined the need for landscaping school grounds. Together with a school district committee of teachers and community leaders interested in…

The Personal Satellite Assistant: An Internal Spacecraft Autonomous Mobile Monitor

NASA Technical Reports Server (NTRS)

Dorais, Gregory A.; Gawdiak, Yuri; Clancy, Daniel (Technical Monitor)

2002-01-01

This paper presents an overview of the research and development effort at the NASA Ames Research Center to create an internal spacecraft autonomous mobile monitor capable of performing intra-vehicular sensing activities by autonomously navigating onboard the International Space Station. We describe the capabilities, mission roles, rationale, high-level functional requirements, and design challenges for an autonomous mobile monitor. The rapid prototyping design methodology used, in which five prototypes of increasing fidelity are designed, is described as well as the status of these prototypes, of which two are operational and being tested, and one is actively being designed. The physical test facilities used to perform ground testing are briefly described, including a micro-gravity test facility that permits a prototype to propel itself in 3 dimensions with 6 degrees-of-freedom as if it were in an micro-gravity environment. We also describe an overview of the autonomy framework and its components including the software simulators used in the development process. Sample mission test scenarios are also described. The paper concludes with a discussion of future and related work followed by the summary.

Ground Systems Development Environment (GSDE) interface requirements analysis

NASA Technical Reports Server (NTRS)

Church, Victor E.; Philips, John; Hartenstein, Ray; Bassman, Mitchell; Ruskin, Leslie; Perez-Davila, Alfredo

1991-01-01

A set of procedural and functional requirements are presented for the interface between software development environments and software integration and test systems used for space station ground systems software. The requirements focus on the need for centralized configuration management of software as it is transitioned from development to formal, target based testing. This concludes the GSDE Interface Requirements study. A summary is presented of findings concerning the interface itself, possible interface and prototyping directions for further study, and results of the investigation of the Cronus distributed applications environment.

Flight prototype regenerative particulate filter system development

NASA Technical Reports Server (NTRS)

Green, D. C.; Garber, P. J.

1974-01-01

The effort to design, fabricate, and test a flight prototype Filter Regeneration Unit used to regenerate (clean) fluid particulate filter elements is reported. The design of the filter regeneration unit and the results of tests performed in both one-gravity and zero-gravity are discussed. The filter regeneration unit uses a backflush/jet impingement method of regenerating fluid filter elements that is highly efficient. A vortex particle separator and particle trap were designed for zero-gravity use, and the zero-gravity test results are discussed. The filter regeneration unit was designed for both inflight maintenance and ground refurbishment use on space shuttle and future space missions.

Differentiability of energy functionals in spin-density-functional theory

NASA Astrophysics Data System (ADS)

Gál, Tamás

2007-06-01

Recently, nonuniqueness of external electrostatic and magnetic fields yielding a given many-electron ground state has been pointed out [K. Capelle and G. Vignale, Phys. Rev. Lett. 86, 5546 (2001); H. Eschrig and W. E. Pickett, Solid State Commun. 118, 123 (2001)], implying the nondifferentiability of the ground-state energy functional of spin-density-functional theory (SDFT), on the basis of which the applicability of widely used DFT methods in SDFT has been put into question and the need for a critical reexamination of those applications has been concluded. Here it is shown, for collinear magnetic fields, that the nonuniqueness of the external potentials in SDFT does not imply the nonexistence of number-conserving functional derivatives as well, with the use of which therefore problems arising from the nondifferentiability are avoided.

Electrostatic attraction of coupled Wigner crystals: finite temperature effects.

PubMed

Lau, A W; Pincus, P; Levine, D; Fertig, H A

2001-05-01

In this paper we present a unified physical picture for the electrostatic attraction between two coupled planar Wigner crystals at finite temperature. This model may facilitate our conceptual understanding of counterion-mediated attractions between (highly) similarly charged planes. By adopting an elastic theory, we show that the total attractive force between them can be (approximately) decomposed into a short-ranged and a long-ranged component. They are evaluated below the melting temperature of the Wigner crystals. In particular, we analyze the temperature dependence of the short-ranged attraction, arising from ground-state configuration, and we argue that thermal fluctuations may drastically reduce its strength. Also, the long-range force agrees exactly with that based on the charge-fluctuation approach. Furthermore, we take quantum contributions to the long-ranged (fluctuation-induced) attraction into account and show how the fractional power law, which scales as d(-7/2) for large interplanar distance d at zero temperature, crosses over to the classical regime d(-3) via an intermediate regime of d(-2).

Fast Plasma Investigation for Magnetospheric Multiscale

NASA Technical Reports Server (NTRS)

Pollock, C.; Moore, T.; Coffey, V.; Dorelli J.; Giles, B.; Adrian, M.; Chandler, M.; Duncan, C.; Figueroa-Vinas, A.; Garcia, K.;

Focusing a fountain of neutral cesium atoms with an electrostatic lens triplet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalnins, Juris G.; Amini, Jason M.; Gould, Harvey

2005-10-15

An electrostatic lens with three focusing elements in an alternating-gradient configuration is used to focus a fountain of cesium atoms in their ground (strong-field-seeking) state. The lens electrodes are shaped to produce only sextupole plus dipole equipotentials which avoids adding the unnecessary nonlinear forces present in cylindrical lenses. Defocusing between lenses is greatly reduced by having all of the main electric fields point in the same direction and be of nearly equal magnitude. The addition of the third lens gave us better control of the focusing strength in the two transverse planes and allowed focusing of the beam to halfmore » the image size in both planes. The beam envelope was calculated for lens voltages selected to produced specific focusing properties. The calculations, starting from first principles, were compared with measured beam sizes and found to be in good agreement. Application to fountain experiments, atomic clocks, and focusing polar molecules in strong-field-seeking states is discussed.« less

Electrostatic coalescence system with independent AC and DC hydrophilic electrodes

DOEpatents

Hovarongkura, A. David; Henry, Jr., Joseph D.

1981-01-01

An improved electrostatic coalescence system is provided in which independent AC and DC hydrophilic electrodes are employed to provide more complete dehydration of an oil emulsion. The AC field is produced between an AC electrode array and the water-oil interface wherein the AC electrode array is positioned parallel to the interface which acts as a grounded electrode. The emulsion is introduced into the AC field in an evenly distributed manner at the interface. The AC field promotes drop-drop and drop-interface coalescence of the water phase in the entering emulsion. The continuous oil phase passes upward through the perforated AC electrode array and enters a strong DC field produced between closely spaced DC electrodes in which small dispersed droplets of water entrained in the continuous phase are removed primarily by collection at hydrophilic DC electrodes. Large droplets of water collected by the electrodes migrate downward through the AC electrode array to the interface. All phase separation mechanisms are utilized to accomplish more complete phase separation.

Discrete and continuum modeling of solvent effects in a twisted intramolecular charge transfer system: The 4-N,N-dimethylaminobenzonitrile (DMABN) molecule.

PubMed

Modesto-Costa, Lucas; Borges, Itamar

2018-08-05

The 4-N,N-dimethylaminobenzonitrile (DMABN) molecule is a prototypical system displaying twisted intramolecular (TICT) charge transfer effects. The ground and the first four electronic excited states (S 1 -S 4 ) in gas phase and upon solvation were studied. Charge transfer values as function of the torsion angle between the donor group (dimethylamine) and the acceptor moiety (benzonitrile) were explicitly computed. Potential energy curves were also obtained. The algebraic diagrammatic construction method at the second-order [ADC(2)] ab initio wave function was employed. Three solvents of increased polarities (benzene, DMSO and water) were investigated using discrete (average solvent electrostatic configuration - ASEC) and continuum (conductor-like screening model - COSMO) models. The results for the S 3 and S 4 excited states and the S 1 -S 4 charge transfer curves were not previously available in the literature. Electronic gas phase and solvent vertical spectra are in good agreement with previous theoretical and experimental results. In the twisted (90°) geometry the optical oscillator strengths have negligible values even for the S 2 bright state. Potential energy curves show two distinct pairs of curves intersecting at decreasing angles or not crossing in the more polar solvents. Charge transfer and electric dipole values allowed the rationalization of these results. The former effects are mostly independent of the solvent model and polarity. Although COSMO and ASEC solvent models mostly lead to similar results, there is an important difference: some crossings of the excitation energy curves appear only in the ASEC solvation model, which has important implications to the photochemistry of DMABN. Copyright © 2018 Elsevier B.V. All rights reserved.

International Aerospace and Ground Conference on Lightning and Static Electricity, 10th, and Congres International Aeronautique, 17th, Paris, France, June 10-13, 1985, Proceedings

NASA Astrophysics Data System (ADS)

1985-12-01

The conference presents papers on statistical data and standards, coupling and indirect effects, meteorology and thunderstorm studies, lightning simulators, fuel ignition hazards, the phenomenology and characterization of lightning, susceptibility and protection of avionics, ground systems protection, lightning locators, aircraft systems protection, structures and materials, electrostatics, and spacecraft protection against static electricity. Particular attention is given to a comparison of published HEMP and natural lightning on the surface of an aircraft, electromagnetic interaction of external impulse fields with aircraft, of thunderstorm currents and lightning charges at the NASA Kennedy Space Center, the design of a fast risetime lightning generator, lightning simulation tests in FAA CV-580 lightning research aircraft, and the energy requirements of an aircraft triggered discharge. Papers are also presented on aircraft lightning attachment at low altitudes, a new form of transient suppressor, a proving ground for lightning research, and a spacecraft materials test in a continuous, broad energy-spectrum electron beam.

Solidification kinetics of a Cu-Zr alloy: ground-based and microgravity experiments

NASA Astrophysics Data System (ADS)

Galenko, P. K.; Hanke, R.; Paul, P.; Koch, S.; Rettenmayr, M.; Gegner, J.; Herlach, D. M.; Dreier, W.; Kharanzhevski, E. V.

2017-04-01

Experimental and theoretical results obtained in the MULTIPHAS-project (ESA-European Space Agency and DLR-German Aerospace Center) are critically discussed regarding solidification kinetics of congruently melting and glass forming Cu50Zr50 alloy samples. The samples are investigated during solidification using a containerless technique in the Electromagnetic Levitation Facility [1]. Applying elaborated methodologies for ground-based and microgravity experimental investigations [2], the kinetics of primary dendritic solidification is quantitatively evaluated. Electromagnetic Levitator in microgravity (parabolic flights and on board of the International Space Station) and Electrostatic Levitator on Ground are employed. The solidification kinetics is determined using a high-speed camera and applying two evaluation methods: “Frame by Frame” (FFM) and “First Frame - Last Frame” (FLM). In the theoretical interpretation of the solidification experiments, special attention is given to the behavior of the cluster structure in Cu50Zr50 samples with the increase of undercooling. Experimental results on solidification kinetics are interpreted using a theoretical model of diffusion controlled dendrite growth.

Electrodynamic Dust Shield Demonstrator

NASA Technical Reports Server (NTRS)

Stankie, Charles G.

2013-01-01

The objective of the project was to design and manufacture a device to demonstrate a new technology developed by NASA's Electrostatics and Surface Physics Laboratory. The technology itself is a system which uses magnetic principles to remove regolith dust from its surface. This project was to create an enclosure that will be used to demonstrate the effectiveness of the invention to The Office of the Chief Technologist. ONE of the most important challenges of space exploration is actually caused by something very small and seemingly insignificant. Dust in space, most notably on the moon and Mars, has caused many unforeseen issues. Dirt and dust on Earth, while a nuisance, can be easily cleaned and kept at bay. However, there is considerably less weathering and erosion in space. As a result, the microscopic particles are extremely rough and abrasive. They are also electrostatically charged, so they cling to everything they make contact with. This was first noted to be a major problem during the Apollo missions. Dust would stick to the spacesuits, and could not be wiped off as predicted. Dust was brought back into the spacecraft, and was even inhaled by astronauts. This is a major health hazard. Atmospheric storms and other events can also cause dust to coat surfaces of spacecraft. This can cause abrasive damage to the craft. The coating can also reduce the effectiveness of thermal insulation and solar panels.' A group of engineers at Kennedy Space Center's Electrostatics and Surface Physics Laboratory have developed a new technology, called the Electrodynamic Dust Shield, to help alleviate these problems. It is based off of the electric curtain concept developed at NASA in 1967. "The EDS is an active dust mitigation technology that uses traveling electric fields to transport electrostatically charged dust particles along surfaces. To generate the traveling electric fields, the EDS consists of a multilayer dielectric coating with an embedded thin electrode grid running a multiphase low frequency AC signal. Electrostatically charged particles, such as those encountered on the moon, Mars, or an asteroid, are carried along by the traveling field due to the action of Coulomb and dielectrophoretic forces."2 The technical details have been described in a separate article. This document details the design and construction process of a small demonstration unit. Once finished, this device will go to the Office of the ChiefTechnologist at NASA headquarters, where it will be used to familiarize the public with the technology. 1 NASA KSC FO Intern, Prototype Development Laboratory, Kennedy Space Center, University of Central Florida Kennedy Space

A new deflection technique applied to an existing scheme of electrostatic accelerator for high energy neutral beam injection in fusion reactor devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pilan, N., E-mail: nicola.pilan@igi.cnr.it; Antoni, V.; De Lorenzi, A.

A scheme of a neutral beam injector (NBI), based on electrostatic acceleration and magneto-static deflection of negative ions, is proposed and analyzed in terms of feasibility and performance. The scheme is based on the deflection of a high energy (2 MeV) and high current (some tens of amperes) negative ion beam by a large magnetic deflector placed between the Beam Source (BS) and the neutralizer. This scheme has the potential of solving two key issues, which at present limit the applicability of a NBI to a fusion reactor: the maximum achievable acceleration voltage and the direct exposure of the BSmore » to the flux of neutrons and radiation coming from the fusion reactor. In order to solve these two issues, a magnetic deflector is proposed to screen the BS from direct exposure to radiation and neutrons so that the voltage insulation between the electrostatic accelerator and the grounded vessel can be enhanced by using compressed SF{sub 6} instead of vacuum so that the negative ions can be accelerated at energies higher than 1 MeV. By solving the beam transport with different magnetic deflector properties, an optimum scheme has been found which is shown to be effective to guarantee both the steering effect and the beam aiming.« less

SHARP: Automated monitoring of spacecraft health and status

NASA Technical Reports Server (NTRS)

Atkinson, David J.; James, Mark L.; Martin, R. Gaius

1991-01-01

Briefly discussed here are the spacecraft and ground systems monitoring process at the Jet Propulsion Laboratory (JPL). Some of the difficulties associated with the existing technology used in mission operations are highlighted. A new automated system based on artificial intelligence technology is described which seeks to overcome many of these limitations. The system, called the Spacecraft Health Automated Reasoning Prototype (SHARP), is designed to automate health and status analysis for multi-mission spacecraft and ground data systems operations. The system has proved to be effective for detecting and analyzing potential spacecraft and ground systems problems by performing real-time analysis of spacecraft and ground data systems engineering telemetry. Telecommunications link analysis of the Voyager 2 spacecraft was the initial focus for evaluation of the system in real-time operations during the Voyager spacecraft encounter with Neptune in August 1989.

SHARP - Automated monitoring of spacecraft health and status

NASA Technical Reports Server (NTRS)

Atkinson, David J.; James, Mark L.; Martin, R. G.

1990-01-01

Briefly discussed here are the spacecraft and ground systems monitoring process at the Jet Propulsion Laboratory (JPL). Some of the difficulties associated with the existing technology used in mission operations are highlighted. A new automated system based on artificial intelligence technology is described which seeks to overcome many of these limitations. The system, called the Spacecraft Health Automated Reasoning Prototype (SHARP), is designed to automate health and status analysis for multi-mission spacecraft and ground data systems operations. The system has proved to be effective for detecting and analyzing potential spacecraft and ground systems problems by performing real-time analysis of spacecraft and ground data systems engineering telemetry. Telecommunications link analysis of the Voyager 2 spacecraft was the initial focus for evaluation of the system in real-time operations during the Voyager spacecraft encounter with Neptune in August 1989.

Prototyping and implementing flight qualifiable semicustom CMOS P-well bulk integrated circuits in the JPL environment

NASA Technical Reports Server (NTRS)

Olson, E. M.

1986-01-01

Presently, there are many difficulties associated with implementing application specific custom or semi-custom (standard cell based) integrated circuits (ICs) into JPL flight projects. One of the primary difficulties is developing prototype semi-custom integrated circuits for use and evaluation in engineering prototype flight hardware. The prototype semi-custom ICs must be extremely cost-effective and yet still representative of flight qualifiable versions of the design. A second difficulty is encountered in the transport of the design from engineering prototype quality to flight quality. Normally, flight quality integrated circuits have stringent quality standards, must be radiation resistant and should consume minimal power. It is often not necessary or cost effective, however, to impose such stringent quality standards on engineering models developed for systems analysis in controlled lab environments. This article presents work originally initiated for ground based applications that also addresses these two problems. Furthermore, this article suggests a method that has been shown successful in prototyping flight quality semi-custom ICs through the Metal Oxide Semiconductor Implementation Service (MOSIS) program run by the University of Southern California's Information Sciences Institute. The method has been used successfully to design and fabricate through the MOSIS three different semi-custom prototype CMOS p-well chips. The three designs make use of the work presented and were designed consistent with design techniques and structures that are flight qualifiable, allowing one hour transfer of the design from engineering model status to flight qualifiable foundry-ready status through methods outlined in this article.

Comparative study of beam losses and heat loads reduction methods in MITICA beam source

NASA Astrophysics Data System (ADS)

Sartori, E.; Agostinetti, P.; Dal Bello, S.; Marcuzzi, D.; Serianni, G.; Sonato, P.; Veltri, P.

2014-02-01

In negative ion electrostatic accelerators a considerable fraction of extracted ions is lost by collision processes causing efficiency loss and heat deposition over the components. Stripping is proportional to the local density of gas, which is steadily injected in the plasma source; its pumping from the extraction and acceleration stages is a key functionality for the prototype of the ITER Neutral Beam Injector, and it can be simulated with the 3D code AVOCADO. Different geometric solutions were tested aiming at the reduction of the gas density. The parameter space considered is limited by constraints given by optics, aiming, voltage holding, beam uniformity, and mechanical feasibility. The guidelines of the optimization process are presented together with the proposed solutions and the results of numerical simulations.

Surface micromachined MEMS deformable mirror based on hexagonal parallel-plate electrostatic actuator

NASA Astrophysics Data System (ADS)

Ma, Wenying; Ma, Changwei; Wang, Weimin

2018-03-01

Deformable mirrors (DM) based on microelectromechanical system (MEMS) technology are being applied in adaptive optics (AO) system for astronomical telescopes and human eyes more and more. In this paper a MEMS DM with hexagonal actuator is proposed and designed. The relationship between structural design and performance parameters, mainly actuator coupling, is analyzed carefully and calculated. The optimum value of actuator coupling is obtained. A 7-element DM prototype is fabricated using a commercial available standard three-layer polysilicon surface multi-user-MEMS-processes (PolyMUMPs). Some key performances, including surface figure and voltage-displacement curve, are measured through a 3D white light profiler. The measured performances are very consistent with the theoretical values. The proposed DM will benefit the miniaturization of AO systems and lower their cost.

High current plasma electron emitter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fiksel, G.; Almagri, A.F.; Craig, D.

1995-07-01

A high current plasma electron emitter based on a miniature plasma source has been developed. The emitting plasma is created by a pulsed high current gas discharge. The electron emission current is 1 kA at 300 V at the pulse duration of 10 ms. The prototype injector described in this paper will be used for a 20 kA electrostatic current injection experiment in the Madison Symmetric Torus (MST) reversed-field pinch. The source will be replicated in order to attain this total current requirement. The source has a simple design and has proven very reliable in operation. A high emission current,more » small size (3.7 cm in diameter), and low impurity generation make the source suitable for a variety of fusion and technological applications.« less

Critical electric field for maximum tunability in nonlinear dielectrics

NASA Astrophysics Data System (ADS)

Akdogan, E. K.; Safari, A.

2006-09-01

The authors develop a self-consistent thermodynamic theory to compute the critical electric field at which maximum tunability is attained in a nonlinear dielectric. They then demonstrate that the stored electrostatic free energy functional has to be expanded at least up to the sixth order in electric field so as to define the critical field, and show that it depends solely on the fourth and sixth order permittivities. They discuss the deficiency of the engineering tunability metric in describing nonlinear dielectric phenomena, introduce a critical field renormalized tunability parameter, and substantiate the proposed formalism by computing the critical electric field for prototypical 0.9Pb(Mg1/3,Nb2/3)-0.1PbTiO3 and Ba(Ti0.85,Sn0.15)O3 paraelectrics.

Recent Progress in Bionic Condensate Microdrop Self-Propelling Surfaces.

PubMed

Gong, Xiaojing; Gao, Xuefeng; Jiang, Lei

2017-12-01

Bionic condensate microdrop self-propelling (CMDSP) surfaces are attracting increased attention as novel, low-adhesivity superhydrophobic surfaces due to their value in fundamental research and technological innovation, e.g., for enhancing heat transfer, energy-effective antifreezing, and electrostatic energy harvesting. Here, the focus is on recent progress in bionic CMDSP surfaces. Metal-based CMDSP surfaces, which are the most promising in their respective fields, are highlighted for use in future applications. The selected topics are divided into four sections: biological prototypes, mechanism and construction rules, fabrication, and applications of metal-based CMDSP surfaces. Finally, the challenges and future development trends in bionic CMDSP surfaces are envisioned, especially the utilization of potential bionic inspiration in the design of more advanced CMDSP surfaces. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Overview of Edge Simulation Laboratory (ESL)

NASA Astrophysics Data System (ADS)

Cohen, R. H.; Dorr, M.; Hittinger, J.; Rognlien, T.; Umansky, M.; Xiong, A.; Xu, X.; Belli, E.; Candy, J.; Snyder, P.; Colella, P.; Martin, D.; Sternberg, T.; van Straalen, B.; Bodi, K.; Krasheninnikov, S.

2006-10-01

The ESL is a new collaboration to build a full-f electromagnetic gyrokinetic code for tokamak edge plasmas using continuum methods. Target applications are edge turbulence and transport (neoclassical and anomalous), and edge-localized modes. Initially the project has three major threads: (i) verification and validation of TEMPEST, the project's initial (electrostatic) edge code which can be run in 4D (neoclassical and transport-timescale applications) or 5D (turbulence); (ii) design of the next generation code, which will include more complete physics (electromagnetics, fluid equation option, improved collisions) and advanced numerics (fully conservative, high-order discretization, mapped multiblock grids, adaptivity), and (iii) rapid-prototype codes to explore the issues attached to solving fully nonlinear gyrokinetics with steep radial gradiens. We present a brief summary of the status of each of these activities.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prentice, John K.; Gardner, David Randall

A methodology was developed for computing the probability that the sensor dart for the 'Near Real-Time Site Characterization for Assured HDBT Defeat' Grand-Challenge LDRD project will survive deployment over a forested region. The probability can be decomposed into three approximately independent probabilities that account for forest coverage, branch density and the physics of an impact between the dart and a tree branch. The probability that a dart survives an impact with a tree branch was determined from the deflection induced by the impact. If a dart that was deflected so that it impacted the ground at an angle of attackmore » exceeding a user-specified, threshold value, the dart was assumed to not survive the impact with the branch; otherwise it was assumed to have survived. A computer code was developed for calculating dart angle of attack at impact with the ground and a Monte Carlo scheme was used to calculate the probability distribution of a sensor dart surviving an impact with a branch as a function of branch radius, length, and height from the ground. Both an early prototype design and the current dart design were used in these studies. As a general rule of thumb, it we observed that for reasonably generic trees and for a threshold angle of attack of 5{sup o} (which is conservative for dart survival), the probability of reaching the ground with an angle of attack less than the threshold is on the order of 30% for the prototype dart design and 60% for the current dart design, though these numbers should be treated with some caution.« less

COMSOL based Simulation on the Effect of Electric Field changes due to Lightning on Ground

NASA Astrophysics Data System (ADS)

Premlet, B.; Joby, N. E.; Sabu, S.

2017-12-01

The phenomenon of lightning is accompanied by localised changes in atmospheric electric fields. In cloud-to-ground strike locations, changes in atmospheric electric fields can even be observed at the ground a few minutes prior to a strike. A lot of research has been done already on the electrostatic changes prior to lightning in the region above ground. Through this work, we investigate into the effects of lightning electric fields on/under ground with the aid of simulations done in COMSOL Multiphysics. Horizontal and vertical profiles of voltage gradient, electric field, polarisation etc. are investigated. Simulation experiments were conducted using a general model of lightning electric fields formed using data recorded by the Electric Field Mills(EFMs) from three diverse parts of the world- Kennedy Space Centre (KSC),Florida (Using GHRC datasets),Sonnblick Observatory, Austria and National Centre for Earth Science Studies Trivandrum (NCESS),India. COMSOL models of the global electric circuit were developed using Sandstone as the base model for ground. Similar works in literature have only dealt with lightning electric fields above the ground. This work is the first step towards a high-level simulation on the effects of atmospheric electric field on/below ground. The results of this simulation work can aid lightning forecasting and preparedness by opening new doors for voltage based prediction methods at ground. It is also a tool to understand phenomena such as fulgurites, corona effect etc. It also helps in the design of buried cables and improved grounding systems. This work can also be a first step towards understanding localised potential variations at the ground during lightning.

Agent Technology, Complex Adaptive Systems, and Autonomic Systems: Their Relationships

NASA Technical Reports Server (NTRS)

Truszkowski, Walt; Rash, James; Rouff, Chistopher; Hincheny, Mike

2004-01-01

To reduce the cost of future spaceflight missions and to perform new science, NASA has been investigating autonomous ground and space flight systems. These goals of cost reduction have been further complicated by nanosatellites for future science data-gathering which will have large communications delays and at times be out of contact with ground control for extended periods of time. This paper describes two prototype agent-based systems, the Lights-out Ground Operations System (LOGOS) and the Agent Concept Testbed (ACT), and their autonomic properties that were developed at NASA Goddard Space Flight Center (GSFC) to demonstrate autonomous operations of future space flight missions. The paper discusses the architecture of the two agent-based systems, operational scenarios of both, and the two systems autonomic properties.

The GSFC Mark-2 three band hand-held radiometer. [thematic mapper for ground truth data collection

NASA Technical Reports Server (NTRS)

Tucker, C. J.; Jones, W. H.; Kley, W. A.; Sundstrom, G. J.

1980-01-01

A self-contained, portable, hand-radiometer designed for field usage was constructed and tested. The device, consisting of a hand-held probe containing three sensors and a strap supported electronic module, weighs 4 1/2 kilograms. It is powered by flashlight and transistor radio batteries, utilizes two silicon and one lead sulfide detectors, has three liquid crystal displays, sample and hold radiometric sampling, and its spectral configuration corresponds to LANDSAT-D's thematic mapper bands. The device was designed to support thematic mapper ground-truth data collection efforts and to facilitate 'in situ' ground-based remote sensing studies of natural materials. Prototype instruments were extensively tested under laboratory and field conditions with excellent results.

Oscar: a portable prototype system for the study of climate variability

NASA Astrophysics Data System (ADS)

Madonna, Fabio; Rosoldi, Marco; Amato, Francesco

2015-04-01

The study of the techniques for the exploitation of solar energy implies the knowledge of nature, ecosystem, biological factors and local climate. Clouds, fog, water vapor, and the presence of large concentrations of dust can significantly affect the way to exploit the solar energy. Therefore, a quantitative characterization of the impact of climate variability at the regional scale is needed to increase the efficiency and sustainability of the energy system. OSCAR (Observation System for Climate Application at Regional scale) project, funded in the frame of the PO FESR 2007-2013, aims at the design of a portable prototype system for the study of correlations among the trends of several Essential Climate Variables (ECVs) and the change in the amount of solar irradiance at the ground level. The final goal of this project is to provide a user-friendly low cost solution for the quantification of the impact of regional climate variability on the efficiency of solar cell and concentrators to improve the exploitation of natural sources. The prototype has been designed on the basis of historical measurements performed at CNR-IMAA Atmospheric Observatory (CIAO). Measurements from satellite and data from models have been also considered as ancillary to the study, above all, to fill in the gaps of existing datasets. In this work, the results outcome from the project activities will be presented. The results include: the design and implementation of the prototype system; the development of a methodology for the estimation of the impact of climate variability, mainly due to aerosol, cloud and water vapor, on the solar irradiance using the integration of the observations potentially provided by prototype; the study of correlation between the surface radiation, precipitation and aerosols transport. In particular, a statistical study will be presented to assess the impact of the atmosphere on the solar irradiance at the ground, quantifying the contribution due to aerosol and clouds and separating their effect on the direct and the diffuse components of the solar radiation. This also aims to provide recommendations to the manufacturer of the devices used to exploit solar radiation.

Operational Prototype Development of a Global Aircraft Radiation Exposure Nowcast

NASA Astrophysics Data System (ADS)

Mertens, Christopher; Kress, Brian; Wiltberger, Michael; Tobiska, W. Kent; Bouwer, Dave

Galactic cosmic rays (GCR) and solar energetic particles (SEP) are the primary sources of human exposure to high linear energy transfer (LET) radiation in the atmosphere. High-LET radiation is effective at directly breaking DNA strands in biological tissue, or producing chemically active radicals in tissue that alter the cell function, both of which can lead to cancer or other adverse health effects. A prototype operational nowcast model of air-crew radiation exposure is currently under development and funded by NASA. The model predicts air-crew radiation exposure levels from both GCR and SEP that may accompany solar storms. The new air-crew radiation exposure model is called the Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) model. NAIRAS will provide global, data-driven, real-time exposure predictions of biologically harmful radiation at aviation altitudes. Observations are utilized from the ground (neutron monitors), from the atmosphere (the NCEP Global Forecast System), and from space (NASA/ACE and NOAA/GOES). Atmospheric observations characterize the overhead mass shielding and the ground-and space-based observations provide boundary conditions on the incident GCR and SEP particle flux distributions for transport and dosimetry calculations. Radiation exposure rates are calculated using the NASA physics-based HZETRN (High Charge (Z) and Energy TRaNsport) code. An overview of the NAIRAS model is given: the concept, design, prototype implementation status, data access, and example results. Issues encountered thus far and known and/or anticipated hurdles to research to operations transition are also discussed.

High-speed civil transport issues and technology program

NASA Technical Reports Server (NTRS)

Hewett, Marle D.

1992-01-01

A strawman program plan is presented, consisting of technology developments and demonstrations required to support the construction of a high-speed civil transport. The plan includes a compilation of technology issues related to the development of a transport. The issues represent technical areas in which research and development are required to allow airframe manufacturers to pursue an HSCT development. The vast majority of technical issues presented require flight demonstrated and validated solutions before a transport development will be undertaken by the industry. The author believes that NASA is the agency best suited to address flight demonstration issues in a concentrated effort. The new Integrated Test Facility at NASA Dryden Flight Research Facility is considered ideally suited to the task of supporting ground validations of proof-of-concept and prototype system demonstrations before night demonstrations. An elaborate ground hardware-in-the-loop (iron bird) simulation supported in this facility provides a viable alternative to developing an expensive fill-scale prototype transport technology demonstrator. Drygen's SR-71 assets, modified appropriately, are a suitable test-bed for supporting flight demonstrations and validations of certain transport technology solutions. A subscale, manned or unmanned flight demonstrator is suitable for flight validation of transport technology solutions, if appropriate structural similarity relationships can be established. The author contends that developing a full-scale prototype transport technology demonstrator is the best alternative to ensuring that a positive decision to develop a transport is reached by the United States aerospace industry.

Development of a Ground Test and Analysis Protocol for NASA's NextSTEP Phase 2 Habitation Concepts

NASA Technical Reports Server (NTRS)

Gernhardt, Michael L.; Beaton, Kara H.; Chappell, Steven P.; Bekdash, Omar S.; Abercromby, Andrew F. J.

2018-01-01

The NASA Next Space Technologies for Exploration Partnerships (NextSTEP) program is a public-private partnership model that seeks commercial development of deep space exploration capabilities to support human spaceflight missions around and beyond cislunar space. NASA first issued the Phase 1 NextSTEP Broad Agency Announcement to U.S. industries in 2014, which called for innovative cislunar habitation concepts that leveraged commercialization plans for low-Earth orbit. These habitats will be part of the Deep Space Gateway (DSG), the cislunar space station planned by NASA for construction in the 2020s. In 2016, Phase 2 of the NextSTEP program selected five commercial partners to develop ground prototypes. A team of NASA research engineers and subject matter experts (SMEs) have been tasked with developing the ground-test protocol that will serve as the primary means by which these Phase 2 prototypes will be evaluated. Since 2008, this core test team has successfully conducted multiple spaceflight analog mission evaluations utilizing a consistent set of operational tools, methods, and metrics to enable the iterative development, testing, analysis, and validation of evolving exploration architectures, operations concepts, and vehicle designs. The purpose of implementing a similar evaluation process for the Phase 2 Habitation Concepts is to consistently evaluate different commercial partner ground prototypes to provide data-driven, actionable recommendations for Phase 3. This paper describes the process by which the ground test protocol was developed and the objectives, methods, and metrics by which the NextSTEP Phase 2 Habitation Concepts will be rigorously and systematically evaluated. The protocol has been developed using both a top-down and bottom-up approach. Top-down development began with the Human Exploration and Operations Mission Directorate (HEOMD) exploration objectives and ISS Exploration Capability Study Team (IECST) candidate flight objectives. Strategic questions and associated rationales, derived from these candidate architectural objectives, provide the framework by which the ground-test protocol will address the DSG stack elements and configurations, systems and subsystems, and habitation, science, and EVA functions. From these strategic questions, high-level functional requirements for the DSG were drafted and associated ground-test objectives and analysis protocols were established. Bottom-up development incorporated objectives from NASA SMEs in autonomy, avionics and software, communication, environmental control and life support systems, exercise, extravehicular activity, exploration medical operations, guidance navigation and control, human factors and behavioral performance, human factors and habitability, logistics, Mission Control Center operations, power, radiation, robotics, safety and mission assurance, science, simulation, structures, thermal, trash management, and vehicle health. Top-down and bottom-up objectives were integrated to form overall functional requirements - ground-test objectives and analysis mapping. From this mapping, ground-test objectives were organized into those that will be evaluated through inspection, demonstration, analysis, subsystem standalone testing, and human-in-the-loop (HITL) testing. For the HITL tests, mission-like timelines, procedures, and flight rules have been developed to directly meet ground test objectives and evaluate specific functional requirements. Data collected from these assessments will be analyzed to determine the acceptability of habitation element configurations and the combinations of capabilities that will result in the best habitation platform to be recommended by the test team for Phase 3.

A Distance Detector with a Strip Magnetic MOSFET and Readout Circuit.

PubMed

Sung, Guo-Ming; Lin, Wen-Sheng; Wang, Hsing-Kuang

2017-01-10

This paper presents a distance detector composed of two separated metal-oxide semiconductor field-effect transistors (MOSFETs), a differential polysilicon cross-shaped Hall plate (CSHP), and a readout circuit. The distance detector was fabricated using 0.18 μm 1P6M Complementary Metal-Oxide Semiconductor (CMOS) technology to sense the magnetic induction perpendicular to the chip surface. The differential polysilicon CSHP enabled the magnetic device to not only increase the magnetosensitivity but also eliminate the offset voltage generated because of device mismatch and Lorentz force. Two MOSFETs generated two drain currents with a quadratic function of the differential Hall voltages at CSHP. A readout circuit-composed of a current-to-voltage converter, a low-pass filter, and a difference amplifier-was designed to amplify the current difference between two drains of MOSFETs. Measurements revealed that the electrostatic discharge (ESD) could be eliminated from the distance sensor by grounding it to earth; however, the sensor could be desensitized by ESD in the absence of grounding. The magnetic influence can be ignored if the magnetic body (human) stays far from the magnetic sensor, and the measuring system is grounded to earth by using the ESD wrist strap (Strap E-GND). Both 'no grounding' and 'grounding to power supply' conditions were unsuitable for measuring the induced Hall voltage.

Electrostatic engineering of strained ferroelectric perovskites from first principles

NASA Astrophysics Data System (ADS)

Cazorla, Claudio; Stengel, Massimiliano

2015-12-01

Design of novel artificial materials based on ferroelectric perovskites relies on the basic principles of electrostatic coupling and in-plane lattice matching. These rules state that the out-of-plane component of the electric displacement field and the in-plane components of the strain are preserved across a layered superlattice, provided that certain growth conditions are respected. Intense research is currently directed at optimizing materials functionalities based on these guidelines, often with remarkable success. Such principles, however, are of limited practical use unless one disposes of reliable data on how a given material behaves under arbitrary electrical and mechanical boundary conditions. Here we demonstrate, by focusing on the prototypical ferroelectrics PbTiO3 and BiFeO3 as test cases, how such information can be calculated from first principles in a systematic and efficient way. In particular, we construct a series of two-dimensional maps that describe the behavior of either compound (e.g., concerning the ferroelectric polarization and antiferrodistortive instabilities) at any conceivable choice of the in-plane lattice parameter, a , and out-of-plane electric displacement, D . In addition to being of immediate practical applicability to superlattice design, our results bring new insight into the complex interplay of competing degrees of freedom in perovskite materials and reveal some notable instances where the behavior of these materials depart from what naively is expected.

SSPI - Space Service Provider Infrastructure: Image Information Mining and Management Prototype for a Distributed Environment

NASA Astrophysics Data System (ADS)

Candela, L.; Ruggieri, G.; Giancaspro, A.

2004-09-01

In the sphere of "Multi-Mission Ground Segment" Italian Space Agency project, some innovative technologies such as CORBA[1], Z39.50[2], XML[3], Java[4], Java server Pages[4] and C++ has been experimented. The SSPI system (Space Service Provider Infrastructure) is the prototype of a distributed environment aimed to facilitate the access to Earth Observation (EO) data. SSPI allows to ingests, archive, consolidate, visualize and evaluate these data. Hence, SSPI is not just a database of or a data repository, but an application that by means of a set of protocols, standards and specifications provides a unified access to multi-mission EO data.

Smart SPHERES: A Telerobotic Free-Flyer for Intravehicular Activities in Space

NASA Technical Reports Server (NTRS)

Fong, Terrence; Micire, Mark J.; Morse, Ted; Park, Eric; Provencher, Chris; To, Vinh; Wheeler, D. W.; Mittman, David; Torres, R. Jay; Smith, Ernest

2013-01-01

Smart SPHERES is a prototype free-flying space robot based on the SPHERES platform. Smart SPHERES can be remotely operated by astronauts inside a spacecraft, or by mission controllers on the ground. We developed Smart SPHERES to perform a variety of intravehicular activities (IVA), such as operations inside the International Space Station (ISS). These IVA tasks include environmental monitoring surveys (radiation, sound levels, etc.), inventory, and mobile camera work. In this paper, we first discuss the motivation for free-flying space robots. We then describe the development of the Smart SPHERES prototype, including avionics, software, and data communications. Finally, we present results of initial flight tests on-board the ISS.

Smart SPHERES: A Telerobotic Free-Flyer for Intravehicular Activities in Space

NASA Technical Reports Server (NTRS)

Fong, Terrence; Micire, Mark J.; Morse, Ted; Park, Eric; Provencher, Chris

2013-01-01

Smart SPHERES is a prototype free-flying space robot based on the SPHERES platform. Smart SPHERES can be remotely operated by astronauts inside a spacecraft, or by mission controllers on the ground. We developed Smart SPHERES to perform a variety of intravehicular activities (IVA), such as operations inside the International Space Station (ISS). These IVA tasks include environmental monitoring surveys (radiation, sound levels, etc.), inventory, and mobile camera work. In this paper, we first discuss the motivation for free- flying space robots. We then describe the development of the Smart SPHERES prototype, including avionics, software, and data communications. Finally, we present results of initial flight tests on-board the ISS.

The development and testing of the fast imaging plasma spectrometer and its application in the plasma environment at Mercury

NASA Astrophysics Data System (ADS)

Koehn, Patrick Leo

The plasma environment at Mercury is a rich laboratory for studying the interaction of the solar wind with a planet. Three primary populations of ions exist at Mercury: solar wind, magnetospheric particles, and pickup ions. Pickup ions are generated through the ionization of Mercury's exosphere or are sputtered particles from the Mercury surface. A comprehensive mission to Mercury should include a sensor that is able to determine the dynamical properties and composition of all three plasma components. The Fast Imaging Plasma Spectrometer (FIPS) is an instrument to measure the composition of these ion populations and their three-dimensional velocity distribution functions. It is lightweight, fast, and has a very large field of view, and these properties made possible its accommodation within the highly mass- constrained payload of MESSENGER (MErcury: Surface, Space ENvironment, GEochemistry, Ranging) mission, a Mercury orbiter. This work details the development cycle of FIPS, from concept to prototype testing. It begins with science studies of the magnetospheric and pickup ion environments of Mercury, using state-of-the-art computer simulations to produce static and quasi-dynamic magnetospheric systems. Predictions are made of the spatially variable plasma environment at Mercury, and the temporally varying magnetosphere-solar wind interaction is examined. Pickup ion studies provide insights to particle loss mechanisms and the nature of the radar-bright regions at the Hermean poles. These studies produce science requirements for successfully measuring this environment with an orbiting mass spectrometer. With these science requirements in mind, a concept for a new electrostatic analyzer is created. This concept is considered from a theoretical standpoint, and compared with other, similarly performing instruments, both of the past and currently in use. The development cycle continues with instrument simulation, which allows the design to be adjusted to fit within the science requirements of the mission. Finally, a prototype electrostatic is constructed and tested in a space- simulating vacuum chamber system. The results of these tests are compared with the simulation results, and ultimately shown to fit within the science requirements for the MESSENGER mission.

Development of thermal control methods for specialized components and scientific instruments at very low temperatures (follow-on)

NASA Technical Reports Server (NTRS)

Wright, J. P.; Wilson, D. E.

1976-01-01

Many payloads currently proposed to be flown by the space shuttle system require long-duration cooling in the 3 to 200 K temperature range. Common requirements also exist for certain DOD payloads. Parametric design and optimization studies are reported for multistage and diode heat pipe radiator systems designed to operate in this temperature range. Also optimized are ground test systems for two long-life passive thermal control concepts operating under specified space environmental conditions. The ground test systems evaluated are ultimately intended to evolve into flight test qualification prototypes for early shuttle flights.

Aircraft Integration and Flight Testing of 4STAR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flynn, CJ; Kassianov, E; Russell, P

2012-10-12

Under funding from the U.S. Dept. of Energy, in conjunction with a funded NASA 2008 ROSES proposal, with internal support from Battelle Pacific Northwest Division (PNWD), and in collaboration with NASA Ames Research Center, we successfully integrated the Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR-Air) instrument for flight operation aboard Battelle’s G-1 aircraft and conducted a series of airborne and ground-based intensive measurement campaigns (hereafter referred to as “intensives”) for the purpose of maturing the initial 4STAR-Ground prototype to a flight-ready science-ready configuration.

Electrostatic generator/motor having rotors of varying thickness and a central stator electrically connected together into two groups

DOEpatents

Post, Richard F.

2010-11-16

A sub-module consists of a set of two outer sets of stationary fan-blade-shaped sectors. These outer sectors include conductive material and are maintained at ground potential in several examples. Located midway between them is a set of stationary sector plates with each plate being electrically insulated from the others. An example provides that the inner sector plates are connected together alternately, forming two groups of parallel-connected condensers that are then separately connected, through high charging circuit resistances, to a source of DC potential with respect to ground, with an additional connecting lead being provided for each group to connect their output as an AC output to a load. These same leads can he used, when connected to a driver circuit, to produce motor action.

ACTS Ka-Band Earth Stations: Technology, Performance, and Lessons Learned

NASA Technical Reports Server (NTRS)

Reinhart, Richard C.; Struharik, Steven J.; Diamond, John J.; Stewart, David

2000-01-01

The Advanced Communications Technology Satellite (ACTS) Project invested heavily in prototype Ka-band satellite ground terminals to conduct an experiments program with ACTS. The ACTS experiments program proposed to validate Ka-band satellite and ground-station technology, demonstrate future telecommunication services, demonstrate commercial viability and market acceptability of these new services, evaluate system networking and processing technology, and characterize Ka-band propagation effects, including development of techniques to mitigate signal fading. This paper will present a summary of the fixed ground terminals developed by the NASA Glenn Research Center and its industry partners, emphasizing the technology and performance of the terminals and the lessons learned throughout their 6-year operation, including the inclined orbit phase-of-operations. The fixed ground stations used for experiments by government, academic, and commercial entities used reflector-based offset-fed antenna systems with antennas ranging in size from 0.35 to 3.4 in. in diameter. Gateway earth stations included two systems referred to as the NASA Ground Station (NGS) and the Link Evaluation Terminal (LET).

Common approach to solving SGEMP, DEMP, and ESD survivability

NASA Technical Reports Server (NTRS)

Ling, D.

1977-01-01

System Generated Electromagnetic Pulse (SGEMP) and Dispersed Electromagnetic Pulse DEMP) are nuclear generated spacecraft environments. Electrostatic discharge (ESD) is a natural spacecraft environment resulting from differential charging in magnetic substorms. All three phenomena, though differing in origin, result in the same problem to the spacecraft and that is Electromagnetic Interference (EMI). A common design approach utilizing a spacecraft structural Faraday Cage is presented which helps solve the EMI problem. Also, other system design techniques are discussed which minimize the magnitude of these environments through control of materials and electrical grounding configuration.

Electrostatic Technology for Control of Dust and Hydrocarbon Vapors in High Power Laser Systems.

DTIC Science & Technology

1982-04-01

interest in that there is an intense corona discharge from the high volt- age (-17 kV) needles to the grounded screen as shown in Figure 1. This generates a...optimum arrangement, in terms of needle -to- needle spacing, needle -to-screen distance and screen opening dimensions? b. How shall the repulsion system be...the optical path? 5 To settle question a, it was necessary to build and test a number of needle -screen systems since there was no theory that could be

Quantum/molecular mechanics study of firefly bioluminescence on luciferase oxidative conformation

NASA Astrophysics Data System (ADS)

Pinto da Silva, Luís; Esteves da Silva, Joaquim C. G.

2014-07-01

This is the first report of a computational study of the color tuning mechanism of firefly bioluminescence, using the oxidative conformation of luciferase. The results of these calculations demonstrated that the electrostatic field generated by luciferase is fundamental both for the emission shift and efficiency. Further calculations indicated that a shift in emission is achieved by modulating the energy, at different degrees, of the emissive and ground states. These differences in energy modulation will then lead to changes in the energy gap between the states.

Sensitivity of Spaceborne and Ground Radar Comparison Results to Data Analysis Methods and Constraints

NASA Technical Reports Server (NTRS)

Morris, Kenneth R.; Schwaller, Mathew

2011-01-01

With the availability of active weather radar observations from space from the Precipitation Radar (PR) on board the Tropical Rainfall Measuring Mission (TR.MM) satellite, numerous studies have been performed comparing PR reflectivity and derived rain rates to similar observations from ground-based weather radars (GR). These studies have used a variety of algorithms to compute matching PR and GR volumes for comparison. Most studies have used a fixed 3-dimensional Cartesian grid centered on the ground radar, onto which the PR and GR data are interpolated using a proprietary approach and/or commonly available GR analysis software (e.g., SPRINT, REORDER). Other studies have focused on the intersection of the PR and GR viewing geometries either explicitly or using a hybrid of the fixed grid and PR/GR common fields of view. For the Dual-Frequency Precipitation Radar (DPR) of the upcoming Global Precipitation Measurement (GPM) mission, a prototype DPR/GR comparison algorithm based on similar TRMM PR data has been developed that defines the common volumes in terms of the geometric intersection of PR and GR rays, where smoothing of the PR and GR data are minimized and no interpolation is performed. The PR and GR volume-averaged reflectivity values of each sample volume are accompanied by descriptive metadata, for attributes including the variability and maximum of the reflectivity within the sample volume, and the fraction of range gates in the sample average having reflectivity values above an adjustable detection threshold (typically taken to be 18 dBZ for the PR). Sample volumes are further characterized by rain type (Stratiform or Convective), proximity to the melting layer, underlying surface (land/water/mixed), and the time difference between the PR and GR observations. The mean reflectivity differences between the PR and GR can differ between data sets produced by the different analysis methods; and for the GPM prototype, by the type of constraints and categorization applied to the data. In this paper, we will show results comparing the 3-D gridded analysis "black box" approach to the GPM prototype volume-matching approach, using matching TRMM PR and WSR-88D ground radar data. The affects of applying data constraints and data categorizations on the volume-matched data to the results will be shown, and explanations of the differences in terms of data and analysis algorithm characteristics will be presented. Implications of the differences to the determination of PR/DPR calibration differences and use of ground radar data to evaluate the PR and DPR attenuation correction algorithms will be discussed.

Compact Analyzer/Controller For Oxygen-Enrichment System

NASA Technical Reports Server (NTRS)

Puster, Richard L.; Singh, Jag J.; Sprinkle, Danny R.

1990-01-01

System controls hypersonic air-breathing engine tests. Compact analyzer/controller developed, built, and tested in small-scale wind tunnel prototype of the 8' HTT (High-Temperature Tunnel). Monitors level of oxygen and controls addition of liquid oxygen to enrich atmosphere for combustion. Ensures meaningful ground tests of hypersonic engines in range of speeds from mach 4 to mach 7.

Prototyping the Use of Dispersion Models to Predict Ground Concentrations During Burning of Deployed Military Waste

DTIC Science & Technology

2012-03-22

Fabric 3.85% Polypropylene (PP) (Class 5 plastics, soda cups, yogurt boxes, syrup bottles, prescription bottles) 1.32% Yard waste 5.67% PVC (Class 3...plastics, milk jugs) 1.23% Cardboard 31.33% Polypropylene (PP) (Class 5 plastics, soda cups, yogurt boxes, syrup bottles, prescription bottles) 0.62

Autonomy and Sensor Webs: The Evolution of Mission Operations

NASA Technical Reports Server (NTRS)

Sherwood, Rob

2008-01-01

Demonstration of these sensor web capabilities will enable fast responding science campaigns that combine spaceborne, airborne, and ground assets. Sensor webs will also require new operations paradigms. These sensor webs will be operated directly by scientists using science goals to control their instruments. We will explore these new operations architectures through a study of existing sensor web prototypes.

Whole-genome sequence of Escherichia coli serotype O157:H7 strain EDL932 (ATCC 43894)

USDA-ARS?s Scientific Manuscript database

Escherichia coli serotype O157:H7 EDL 933 is a ground beef isolate associated with a 1983 hemorrhagic colitis outbreak. Considered the prototype O157:H7 strain, its derived genome sequence is a standard reference strain for comparative genomic studies of Shiga toxin-producing E. coli (STEC). Here we...

Conversion-Integration of MSFC Nonlinear Signal Diagnostic Analysis Algorithms for Realtime Execution of MSFC's MPP Prototype System

NASA Technical Reports Server (NTRS)

Jong, Jen-Yi

1996-01-01

NASA's advanced propulsion system Small Scale Magnetic Disturbances/Advanced Technology Development (SSME/ATD) has been undergoing extensive flight certification and developmental testing, which involves large numbers of health monitoring measurements. To enhance engine safety and reliability, detailed analysis and evaluation of the measurement signals are mandatory to assess its dynamic characteristics and operational condition. Efficient and reliable signal detection techniques will reduce the risk of catastrophic system failures and expedite the evaluation of both flight and ground test data, and thereby reduce launch turn-around time. During the development of SSME, ASRI participated in the research and development of several advanced non- linear signal diagnostic methods for health monitoring and failure prediction in turbomachinery components. However, due to the intensive computational requirement associated with such advanced analysis tasks, current SSME dynamic data analysis and diagnostic evaluation is performed off-line following flight or ground test with a typical diagnostic turnaround time of one to two days. The objective of MSFC's MPP Prototype System is to eliminate such 'diagnostic lag time' by achieving signal processing and analysis in real-time. Such an on-line diagnostic system can provide sufficient lead time to initiate corrective action and also to enable efficient scheduling of inspection, maintenance and repair activities. The major objective of this project was to convert and implement a number of advanced nonlinear diagnostic DSP algorithms in a format consistent with that required for integration into the Vanderbilt Multigraph Architecture (MGA) Model Based Programming environment. This effort will allow the real-time execution of these algorithms using the MSFC MPP Prototype System. ASRI has completed the software conversion and integration of a sequence of nonlinear signal analysis techniques specified in the SOW for real-time execution on MSFC's MPP Prototype. This report documents and summarizes the results of the contract tasks; provides the complete computer source code; including all FORTRAN/C Utilities; and all other utilities/supporting software libraries that are required for operation.

Shaking table test and dynamic response prediction on an earthquake-damaged RC building

NASA Astrophysics Data System (ADS)

Xianguo, Ye; Jiaru, Qian; Kangning, Li

2004-12-01

This paper presents the results from shaking table tests of a one-tenth-scale reinforced concrete (RC) building model. The test model is a protype of a building that was seriously damaged during the 1985 Mexico earthquake. The input ground excitation used during the test was from the records obtained near the site of the prototype building during the 1985 and 1995 Mexico earthquakes. The tests showed that the damage pattern of the test model agreed well with that of the prototype building. Analytical prediction of earthquake response has been conducted for the prototype building using a sophisticated 3-D frame model. The input motion used for the dynamic analysis was the shaking table test measurements with similarity transformation. The comparison of the analytical results and the shaking table test results indicates that the response of the RC building to minor and the moderate earthquakes can be predicated well. However, there is difference between the predication and the actual response to the major earthquake.

The solar-powered Helios Prototype flying wing frames two modified F-15 research aircraft in a hanga

NASA Technical Reports Server (NTRS)

2002-01-01

The solar-powered Helios Prototype flying wing frames two modified F-15 research aircraft in a hangar at NASA's Dryden flight Research Center, Edwards, California. The elongated 247-foot span lightweight aircraft, resting on its ground maneuvering dolly, stretched almost the full length of the 300-foot long hangar while on display during a visit of NASA Administrator Sean O'Keefe and other NASA officials on Jan. 31, 2002. The unique solar-electric flying wing reached an altitude of 96,863 feet during an almost 17-hour flight near Hawaii on Aug. 13, 2001, a world record for sustained horizontal flight by a non-rocket powered aircraft. Developed by AeroVironment, Inc., under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project, the Helios Prototype is the forerunner of a planned fleet of slow-flying, long duration, high-altitude uninhabited aerial vehicles (UAV) which can serve as 'atmospheric satellites,' performing Earth science missions or functioning as telecommunications relay platforms in the stratosphere.

Environmental assessment of SP-100 ground engineering system test site: Hanford Site, Richland, Washington

NASA Astrophysics Data System (ADS)

1988-12-01

The US Department of Energy (DOE) proposes to modify an existing reactor containment building (decommissioned Plutonium Recycle Test Reactor (PRTR) 309 Building) to provide ground test capability for the prototype SP-100 reactor. The 309 Building (Figure 1.1) is located in the 300 Area on the Hanford Site in Washington State. The National Environmental Policy Act (NEPA) requires that Federal agencies assess the potential impacts that their actions may have on the environment. This Environmental Assessment describes the consideration given to environmental impacts during reactor concept and test site selection, examines the environmental effects of the DOE proposal to ground test the nuclear subsystem, describes alternatives to the proposed action, and examines radiological risks of potential SP-100 use in space.

A Low Cost Traveling Wave Tube for Wireless Communications

NASA Technical Reports Server (NTRS)

Vancil, Bernard Kenneth; Wintucky, Edwin G.; Williams, W. D. (Technical Monitor)

2002-01-01

Demand for high data rate wireless communications is pushing up amplifier power, bandwidth and frequency requirements. Some systems are using vacuum electron devices again because solid-state power amplifiers are not able to efficiently meet the new requirements. The traveling wave tube is the VED of choice because of its excellent broadband capability as well as high power efficiency and frequency. But TWTs are very expensive on a per watt basis below about 200 watts of output power. We propose a new traveling wave tube that utilizes cathode ray tube construction technology and electrostatic focusing. We believe the tube can be built in quantity for under $1,000 each. We discuss several traveling wave tube slow wave circuits that lend themselves to the new construction. We will present modeling results and data on prototype devices.

A ground-water-quality monitoring program for Nevada

USGS Publications Warehouse

Nowlin, Jon O.

1986-01-01

A program was designed for the systematic monitoring of ground-water quality in Nevada. Basic hydrologic and water-quality principles are discussed in the formulation of a rational approach to developing a statewide monitoring program. A review of ground-water monitoring efforts in Nevada through 1977 indicates that few requirements for an effective statewide program are being met. A suggested program has been developed that consists of five major elements: (1) A Background-Quality Network to assess the existing water quality in Nevada aquifers, (2) a Contamination Source Inventory of known or potential threats to ground-water quality, (3) Surveillance Networks to monitor ground-water quality in selected hydrographic areas, (4) Intensive Surveys of individual instances of known or potential ground-water contamination, and (5) Ground-Water Data File to manage data generated by the other monitoring elements. Two indices have been developed to help assign rational priorities for monitoring ground water in the 255 hydrographic areas of Nevada: (1) A Hydrographic-Area Priority Index for surveillance monitoring, and (2) A Development-Potential Index for background monitoring of areas with little or no current development. Requirements for efficient management of data from ground-water monitoring are discussed and the three major systems containing Nevada ground-water data are reviewed. More than 11,000 chemical analyses of ground water have been acquired from existing systems and incorporated into a prototype data base.

An electrostatic Si e-gun and a high temperature elemental B source for Si heteroepitaxial growth

NASA Astrophysics Data System (ADS)

Scarinci, F.; Casella, A.; Lagomarsino, S.; Fiordelisi, M.; Strappaveccia, P.; Gambacorti, N.; Grimaldi, M. G.; Xue, LiYing

1996-08-01

In this paper we present two kind of sources used in Si MBE growth: a Si source where an electron beam is electrostatically deflected onto a Si rod and a high temperature B source to be used for p-doping. Both sources have been designed and constructed at IESS. The Si source is constituted of a Si rod mounted on a 3/4″ flange with high-voltage connector. A W filament held at high voltage (up to 2000 V) is heated by direct current. Electrons from the filament are electrostatically focused onto the Si rod which is grounded. This mounting allows a minimum heating dispersion and no contamination, because the only hot objects are the Si rod and the W filament which is mounted in such a way that it cannot see the substrate. Growth rates of 10 Å/min on a substrate at 20 cm from the source have been measured. Auger and LEED have shown no contamination. The B source is constituted of a graphite block heated by direct current. A pyrolitic graphite crucible put in the graphite heater contains the elemental B. The cell is water cooled and contains Ta screens to avoid heat dispersion. It has been tested up to a temperature of 1700°C. P-doped Si 1- xGe x layers have been grown and B concentration has been measured by SIMS. A good control and reproducibility has been attained.

Electrical Activity in Martian Dust Storms

NASA Astrophysics Data System (ADS)

Majid, W.; Arabshahi, S.; Kocz, J.

2016-12-01

Dust storms on Mars are predicted to be capable of producing electrostatic fields and discharges, even larger than those in dust storms on Earth. Such electrical activity poses serious risks to any Human exploration of the planet and the lack of sufficient data to characterize any such activity has been identified by NASA's MEPAG as a key human safety knowledge gap. There are three key elements in the characterization of Martian electrostatic discharges: dependence on Martian environmental conditions, frequency of occurrence, and the strength of the generated electric fields. We will describe a recently deployed detection engine using NASA's Deep Space Network (DSN) to carry out a long term monitoring campaign to search for and characterize the entire Mars hemisphere for powerful discharges during routine tracking of spacecraft at Mars on an entirely non-interfering basis. The resulting knowledge of Mars electrical activity would allow NASA to plan risk mitigation measures to ensure human safety during Mars exploration. In addition, these measurements will also allow us to place limits on presence of oxidants such as H2O2 that may be produced by such discharges, providing another measurement point for models describing Martian atmospheric chemistry and habitability. Because of the continuous Mars telecommunication needs of NASA's Mars-based assets, the DSN is the only instrument in the world that combines long term, high cadence, observing opportunities with large sensitive telescopes, making it a unique asset worldwide in searching for and characterizing electrostatic activity at Mars from the ground.

A suite of diagnostics to validate and optimize the prototype ITER neutral beam injector

NASA Astrophysics Data System (ADS)

Pasqualotto, R.; Agostini, M.; Barbisan, M.; Brombin, M.; Cavazzana, R.; Croci, G.; Dalla Palma, M.; Delogu, R. S.; De Muri, M.; Muraro, A.; Peruzzo, S.; Pimazzoni, A.; Pomaro, N.; Rebai, M.; Rizzolo, A.; Sartori, E.; Serianni, G.; Spagnolo, S.; Spolaore, M.; Tardocchi, M.; Zaniol, B.; Zaupa, M.

2017-10-01

The ITER project requires additional heating provided by two neutral beam injectors using 40 A negative deuterium ions accelerated at 1 MV. As the beam requirements have never been experimentally met, a test facility is under construction at Consorzio RFX, which hosts two experiments: SPIDER, full-size 100 kV ion source prototype, and MITICA, 1 MeV full-size ITER injector prototype. Since diagnostics in ITER injectors will be mainly limited to thermocouples, due to neutron and gamma radiation and to limited access, it is crucial to thoroughly investigate and characterize in more accessible experiments the key parameters of source plasma and beam, using several complementary diagnostics assisted by modelling. In SPIDER and MITICA the ion source parameters will be measured by optical emission spectroscopy, electrostatic probes, cavity ring down spectroscopy for H^- density and laser absorption spectroscopy for cesium density. Measurements over multiple lines-of-sight will provide the spatial distribution of the parameters over the source extension. The beam profile uniformity and its divergence are studied with beam emission spectroscopy, complemented by visible tomography and neutron imaging, which are novel techniques, while an instrumented calorimeter based on custom unidirectional carbon fiber composite tiles observed by infrared cameras will measure the beam footprint on short pulses with the highest spatial resolution. All heated components will be monitored with thermocouples: as these will likely be the only measurements available in ITER injectors, their capabilities will be investigated by comparison with other techniques. SPIDER and MITICA diagnostics are described in the present paper with a focus on their rationale, key solutions and most original and effective implementations.

Generating Safety-Critical PLC Code From a High-Level Application Software Specification

NASA Technical Reports Server (NTRS)

2008-01-01

The benefits of automatic-application code generation are widely accepted within the software engineering community. These benefits include raised abstraction level of application programming, shorter product development time, lower maintenance costs, and increased code quality and consistency. Surprisingly, code generation concepts have not yet found wide acceptance and use in the field of programmable logic controller (PLC) software development. Software engineers at Kennedy Space Center recognized the need for PLC code generation while developing the new ground checkout and launch processing system, called the Launch Control System (LCS). Engineers developed a process and a prototype software tool that automatically translates a high-level representation or specification of application software into ladder logic that executes on a PLC. All the computer hardware in the LCS is planned to be commercial off the shelf (COTS), including industrial controllers or PLCs that are connected to the sensors and end items out in the field. Most of the software in LCS is also planned to be COTS, with only small adapter software modules that must be developed in order to interface between the various COTS software products. A domain-specific language (DSL) is a programming language designed to perform tasks and to solve problems in a particular domain, such as ground processing of launch vehicles. The LCS engineers created a DSL for developing test sequences of ground checkout and launch operations of future launch vehicle and spacecraft elements, and they are developing a tabular specification format that uses the DSL keywords and functions familiar to the ground and flight system users. The tabular specification format, or tabular spec, allows most ground and flight system users to document how the application software is intended to function and requires little or no software programming knowledge or experience. A small sample from a prototype tabular spec application is shown.

Electrostatics in the environment: How they may affect health and productivity

NASA Astrophysics Data System (ADS)

Jamieson, K. S.; Simon, H. M. Ap; Bell, J. N. B.

2008-12-01

Lifestyles and the built environment have changed considerably during the past century and have greatly influenced the electric field, small air ion and charged submicron aerosol regimes to which individuals are often exposed. In particular the use of electrical items, synthetic materials/finishes and low humidity levels that can lead to the generation of high electrostatic charges, along with inadequate grounding protocols and building techniques which create 'Faraday cage'-like conditions, have all greatly altered the electromagnetic nature of the microclimates many people occupy for prolonged periods of time. It is suggested that the type, polarity and strengths of electric fields individuals are exposed to may affect their likelihood of succumbing to ill-health through influencing biological functioning, oxygen-uptake and retention rates of inhaled submicron contaminants to a far greater degree than previously realised. These factors can also influence the degree of local surface contamination and adhesion that occurs. It is further suggested that both health and work productivity can be affected by such factors, and that improved 'best practice' electro-hygiene/productivity protocols should be adopted wherever practical.

DFT computational analysis of piracetam

NASA Astrophysics Data System (ADS)

Rajesh, P.; Gunasekaran, S.; Seshadri, S.; Gnanasambandan, T.

2014-11-01

Density functional theory calculation with B3LYP using 6-31G(d,p) and 6-31++G(d,p) basis set have been used to determine ground state molecular geometries. The first order hyperpolarizability (β0) and related properties (β, α0 and Δα) of piracetam is calculated using B3LYP/6-31G(d,p) method on the finite-field approach. The stability of molecule has been analyzed by using NBO/NLMO analysis. The calculation of first hyperpolarizability shows that the molecule is an attractive molecule for future applications in non-linear optics. Molecular electrostatic potential (MEP) at a point in the space around a molecule gives an indication of the net electrostatic effect produced at that point by the total charge distribution of the molecule. The calculated HOMO and LUMO energies show that charge transfer occurs within these molecules. Mulliken population analysis on atomic charge is also calculated. Because of vibrational analysis, the thermodynamic properties of the title compound at different temperatures have been calculated. Finally, the UV-Vis spectra and electronic absorption properties are explained and illustrated from the frontier molecular orbitals.

Innovative Electrostatic Adhesion Technologies

NASA Technical Reports Server (NTRS)

Bryan, Tom; Macleod, Todd; Gagliano, Larry; Williams, Scott; McCoy, Brian

2015-01-01

Developing specialized Electro-Static grippers (commercially used in Semiconductor Manufacturing and in package handling) will allow gentle and secure Capture, Soft Docking, and Handling of a wide variety of materials and shapes (such as upper-stages, satellites, arrays, and possibly asteroids) without requiring physical features or cavities for a pincher or probe or using harpoons or nets. Combined with new rigid boom mechanisms or small agile chaser vehicles, flexible, high speed Electro-Static Grippers can enable compliant capture of spinning objects starting from a safe stand-off distance. Electroadhesion (EA) can enable lightweight, ultra-low-power, compliant attachment in space by using an electrostatic force to adhere similar and dissimilar surfaces. A typical EA enabled device is composed of compliant space-rated materials, such as copper-clad polyimide encapsulated by polymers. Attachment is induced by strong electrostatic forces between any substrate material, such as an exterior satellite panel and a compliant EA gripper pad surface. When alternate positive and negative charges are induced in adjacent planar electrodes in an EA surface, the electric fields set up opposite charges on the substrate and cause an electrostatic adhesion between the electrodes and the induced charges on the substrate. Since the electrodes and the polymer are compliant and can conform to uneven or rough surfaces, the electrodes can remain intimately close to the entire surface, enabling high clamping pressures. Clamping pressures of more than 3 N/cm2 in shear can be achieved on a variety of substrates with ultra-low holding power consumption (measured values are less than 20 microW/Newton weight held). A single EA surface geometry can be used to clamp both dielectric and conductive substrates, with slightly different physical mechanisms. Furthermore EA clamping requires no normal force be placed on the substrate, as conventional docking requires. Internally funded research and development has demonstrated that EA can function effectively in space, even in the presence of strong ultraviolet radiation, atomic oxygen, and free electrons. We created a test setup in an existing vacuum chamber to simulate low-Earth-orbit conditions. An EA mechanism was fabricated and installed in the chamber, instrumented, operated in a vacuum, and subjected to ultraviolet photons and free electrons generated by an in-chamber multipactor electron emitter. Extensions to EA that can add value include proximity and contact sensing and transverse motion or rotation, both of which could enhance docking or assembly applications. Possible next steps include development of targeted applications for ground investigation or on-orbit subsystem performance demonstrations using low cost access to space such as CubeSats.

Innovative Electrostatic Adhesion Technologies

NASA Astrophysics Data System (ADS)

Gagliano, L.; Bryan, T.; Williams, S.; McCoy, B.; MacLeod, T.

Developing specialized Electro-Static grippers (commercially used in Semiconductor Manufacturing and in package handling) will allow gentle and secure Capture, Soft Docking, and Handling of a wide variety of materials and shapes (such as upper-stages, satellites, arrays, and possibly asteroids) without requiring physical features or cavities for a pincher or probe or using harpoons or nets. Combined with new rigid boom mechanisms or small agile chaser vehicles, flexible, high speed Electro-Static Grippers can enable compliant capture of spinning objects starting from a safe stand-off distance. Electroadhesion (EA) can enable lightweight, ultra-low-power, compliant attachment in space by using an electrostatic force to adhere similar and dissimilar surfaces. A typical EA enabled device is composed of compliant space-rated materials, such as copper-clad polyimide encapsulated by polymers. Attachment is induced by strong electrostatic forces between any substrate material, such as an exterior satellite panel and a compliant EA surface. When alternate positive and negative charges are induced in adjacent planar electrodes in an EA surface, the electric fields set up opposite charges on the substrate and cause an electrostatic adhesion between the electrodes and the induced charges on the substrate. Since the electrodes and the polymer are compliant and can conform to uneven or rough surfaces, the electrodes can remain intimately close to the entire surface, enabling high clamping pressures. Clamping pressures of more than 3 N/cm2 in shear can be achieved on a variety of substrates with ultra-low holding power consumption (measured values are less than 20 microW/Newton weight held). A single EA surface geometry can be used to clamp both dielectric and conductive substrates, with slightly different physical mechanisms. Furthermore EA clamping requires no normal force be placed on the substrate, as conventional docking requires. Internally funded research and development has demonstrated that EA can function effectively in space, even in the presence of strong ultraviolet radiation, atomic oxygen, and free electrons. We created a test setup in an existing vacuum chamber to simulate low-Earth-orbit conditions. An EA mechanism was fabricated and installed in the chamber, instrumented, operated in a vacuum, and subjected to ultraviolet photons and free electrons generated by an in-chamber multipactor electron emitter. Extensions to EA that can add value include proximity and contact sensing and transverse motion or rotation, both of which could enhance docking or assembly applications. Possible next steps include development of targeted applications for ground investigation or on-orbit subsystem performance demonstrations using low cost access to space such as CubeSats.

Simulation study on transient electric shock characteristics of human body under high voltage ac transmission lines

NASA Astrophysics Data System (ADS)

Huang, Tao; Zou, Yanhui; Lv, Jianhong; Yang, Jinchun; Tao, Li; Zhou, Jianfei

2017-09-01

Human body under high-voltage AC transmission lines will produce a certain induced voltage due to the electrostatic induction. When the human body contacts with some grounded objects, the charges transfer from the body to the ground and produce contact current which may cause transient electric shock. Using CDEGS and ATP/EMTP, the paper proposes a method for quantitatively calculating the transient electric shock characteristics. It calculates the human body voltage, discharge current and discharge energy under certain 500kV compact-type transmission lines and predicts the corresponding human feelings. The results show that the average root value of discharge current is less than 10mA when the human body is under the 500kV compact-type transmission lines and the human body is overall safe if the transmission lines satisfy the relevant design specifications. It concludes that the electric field strength above the ground should be limited to 4kV/m through the residential area for the purpose of reducing the electromagnetic impact.

Advantages of using subsurface flow constructed wetlands for wastewater treatment in space applications: Ground-based mars base prototype

NASA Astrophysics Data System (ADS)

Nelson, M.; Alling, A.; Dempster, W. F.; van Thillo, M.; Allen, John

Research and design of subsurface flow wetland wastewater treatment systems for a ground-based experimental prototype Mars Base facility has been carried out, using a subsurface flow approach. These systems have distinct advantages in planetary exploration scenarios: they are odorless, relatively low-labor and low-energy, assist in purification of water and recycling of atmospheric CO2, and will support some food crops. An area of 6-8 m2 may be sufficient for integration of wetland wastewater treatment with a prototype Mars Base supporting 4-5 people. Discharge water from the wetland system will be used as irrigation water for the agricultural crop area, thus ensuring complete recycling and utilization of nutrients. Since the primary requirements for wetland treatment systems are warm temperatures and lighting, such bioregenerative systems may be integrated into early Mars base habitats, since waste heat from the lights may be used for temperature maintenance in the human living environment. "Wastewater gardens ™" can be modified for space habitats to lower space and mass requirements. Many of its construction requirements can eventually be met with use of in-situ materials, such as gravel from the Mars surface. Because the technology requires little machinery and no chemicals, and relies more on natural ecological mechanisms (microbial and plant metabolism), maintenance requirements are minimized, and systems can be expected to have long operating lifetimes. Research needs include suitability of Martian soil and gravel for wetland systems, system sealing and liner options in a Mars Base, and wetland water quality efficiency under varying temperature and light regimes.

Two-axis gimbal for air-to-air and air-to-ground laser communications

NASA Astrophysics Data System (ADS)

Talmor, Amnon G.; Harding, Harvard; Chen, Chien-Chung

2016-03-01

For bi-directional links between high-altitude-platforms (HAPs) and ground, and air-to-air communication between such platforms, a hemispherical +30°C field-of-regard and low-drag low-mass two-axis gimbal was designed and prototyped. The gimbal comprises two servo controlled non-orthogonal elevation over azimuth axis, and inner fast steering mirrors for fine field-of-regard adjustment. The design encompasses a 7.5cm diameter aperture refractive telescope in its elevation stage, folded between two flat mirrors with an exit lens leading to a two mirrors miniature Coude-path fixed to the azimuth stage. Multiple gimbal configurations were traded prior to finalizing a selection that met the requirements. The selected design was manifested onboard a carbon fiber and magnesium composite structure, motorized by custom-built servo motors, and commutated by optical encoders. The azimuth stage is electrically connected to the stationary base via slip ring while the elevation stage made of passive optics. Both axes are aligned by custom-built ceramic-on-steel angular contact duplex bearings, and controlled by embedded electronics featuring a rigid-flex PCB architecture. FEA analysis showed that the design is mechanically robust over a temperature range of +60°C to -80°C, and with first mode of natural frequencies above 400Hz. The total mass of the prototyped gimbal is 3.5kg, including the inner optical bench, which contains fast steering mirrors (FSMs) and tracking sensors. Future version of this gimbal, in prototyping stage, shall weigh less than 3.0kg.

The Canadian Forces ILDS: a militarily fielded multisensor vehicle-mounted teleoperated landmine detection system

NASA Astrophysics Data System (ADS)

McFee, John E.; Russell, Kevin L.; Chesney, Robert H.; Faust, Anthony A.; Das, Yogadhish

2006-05-01

The Improved Landmine Detection System (ILDS) is intended to meet Canadian military mine clearance requirements in rear area combat situations and peacekeeping on roads and tracks. The system consists of two teleoperated vehicles and a command vehicle. The teleoperated protection vehicle precedes, clearing antipersonnel mines and magnetic and tilt rod-fuzed antitank mines. It consists of an armoured personnel carrier with a forward looking infrared imager, a finger plow or roller and a magnetic signature duplicator. The teleoperated detection vehicle follows to detect antitank mines. The purpose-built vehicle carries forward looking infrared and visible imagers, a 3 m wide, down-looking sensitive electromagnetic induction detector array and a 3 m wide down-looking ground probing radar, which scan the ground in front of the vehicle. Sensor information is combined using navigation sensors and custom navigation, registration, spatial correspondence and data fusion algorithms. Suspicious targets are then confirmed by a thermal neutron activation detector. The prototype, designed and built by Defence R&D Canada, was completed in October 1997. General Dynamics Canada delivered four production units, based on the prototype concept and technologies, to the Canadian Forces (CF) in 2002. ILDS was deployed in Afghanistan in 2003, making the system the first militarily fielded, teleoperated, multi-sensor vehicle-mounted mine detector and the first with a fielded confirmation sensor. Performance of the prototype in Canadian and independent US trials is summarized and recent results from the production version of the confirmation sensor are discussed. CF operations with ILDS in Afghanistan are described.

Hypersonic propulsion flight tests as essential to air-breathing aerospace plane development

NASA Astrophysics Data System (ADS)

Mehta, U.

Hypersonic air-breathing propulsion utilizing scramjets can fundamentally change transatmospheric acclerators for transportation from low Earth orbits (LEOs). The value and limitations of ground tests, of flight tests, and of computations are presented, and scramjet development requirements are discussed. Near-full-scale hypersonic propulsion flight tests are essential for developing a prototype hypersonic propulsion system and for developing computation-design technology that can be used in designing that system. In order to determine how these objectives should be achieved, some lessons learned from past programs are presented. A conceptual two-stage-to-orbit (TSTO) prototype/experimental aerospace plane is recommended as a means of providing access-to-space and for conducting flight tests. A road map for achieving these objectives is also presented.

Control and Non-Payload Communications (CNPC) Prototype Radio Validation Flight Test Report

NASA Technical Reports Server (NTRS)

Shalkhauser, Kurt A.; Ishac, Joseph A.; Iannicca, Dennis C.; Bretmersky, Steven C.; Smith, Albert E.

2017-01-01

This report provides an overview and results from the unmanned aircraft (UA) Control and Non-Payload Communications (CNPC) Generation 5 prototype radio validation flight test campaign. The radios used in the test campaign were developed under cooperative agreement NNC11AA01A between the NASA Glenn Research Center and Rockwell Collins, Inc., of Cedar Rapids, Iowa. Measurement results are presented for flight tests over hilly terrain, open water, and urban landscape, utilizing radio sets installed into a NASA aircraft and ground stations. Signal strength and frame loss measurement data are analyzed relative to time and aircraft position, specifically addressing the impact of line-of-sight terrain obstructions on CNPC data flow. Both the radio and flight test system are described.

Technology for an intelligent, free-flying robot for crew and equipment retrieval in space

NASA Technical Reports Server (NTRS)

Erickson, J. D.; Reuter, G. J.; Healey, Kathleen J.; Phinney, D. E.

1990-01-01

Crew rescue and equipment retrieval is a Space Station Freedom requirement. During Freedom's lifetime, there is a high probability that a number of objects will accidently become separated. Members of the crew, replacement units, and key tools are examples. Retrieval of these objects within a short time is essential. Systems engineering studies were conducted to identify system requirements and candidate approaches. One such approach, based on a voice-supervised, intelligent, free-flying robot was selected for further analysis. A ground-based technology demonstration, now in its second phase, was designed to provide an integrated robotic hardware and software testbed supporting design of a space-borne system. The ground system, known as the EVA Retriever, is examining the problem of autonomously planning and executing a target rendezvous, grapple, and return to base while avoiding stationary and moving obstacles. The current prototype is an anthropomorphic manipulator unit with dexterous arms and hands attached to a robot body and latched in a manned maneuvering unit. A precision air-bearing floor is used to simulate space. Sensor data include two vision systems and force/proximity/tactile sensors on the hands and arms. Planning for a shuttle file experiment is underway. A set of scenarios and strawman requirements were defined to support conceptual development. Initial design activities are expected to begin in late 1989 with the flight occurring in 1994. The flight hardware and software will be based on lessons learned from both the ground prototype and computer simulations.

Initial Results from Radiometer and Polarized Radar-Based Icing Algorithms Compared to In-Situ Data

NASA Technical Reports Server (NTRS)

Serke, David; Reehorst, Andrew L.; King, Michael

2015-01-01

In early 2015, a field campaign was conducted at the NASA Glenn Research Center in Cleveland, Ohio, USA. The purpose of the campaign is to test several prototype algorithms meant to detect the location and severity of in-flight icing (or icing aloft, as opposed to ground icing) within the terminal airspace. Terminal airspace for this project is currently defined as within 25 kilometers horizontal distance of the terminal, which in this instance is Hopkins International Airport in Cleveland. Two new and improved algorithms that utilize ground-based remote sensing instrumentation have been developed and were operated during the field campaign. The first is the 'NASA Icing Remote Sensing System', or NIRSS. The second algorithm is the 'Radar Icing Algorithm', or RadIA. In addition to these algorithms, which were derived from ground-based remote sensors, in-situ icing measurements of the profiles of super-cooled liquid water (SLW) collected with vibrating wire sondes attached to weather balloons produced a comprehensive database for comparison. Key fields from the SLW-sondes include air temperature, humidity and liquid water content, cataloged by time and 3-D location. This work gives an overview of the NIRSS and RadIA products and results are compared to in-situ SLW-sonde data from one icing case study. The location and quantity of super-cooled liquid as measured by the in-situ probes provide a measure of the utility of these prototype hazard-sensing algorithms.

Grounding electrode and method of reducing the electrical resistance of soils

DOEpatents

Koehmstedt, Paul L.

1980-01-01

A first solution of an electrolyte is injected underground into a volume of soil having negative surface charges on its particles. A cationic surfactant suspended in this solution neutralizes these surface charges of the soil particles within the volume. Following the first solution, a cationic asphalt emulsion suspended in a second solution is injected into the volume. The asphalt emulsion diffuses through the volume and electrostatically bonds with additional soil surrounding the volume such that an electrically conductive water repellant shell enclosing the volume is formed. This shell prevents the leaching of electrolyte from the volume into the additional soil. The second solution also contains a dissolved deliquescent salt which draws water into the volume prior to the formation of the shell. When electrically connected to an electrical installation such as a power line tower, the volume constitutes a grounding electrode for the tower.

Direct impact aerosol sampling by electrostatic precipitation

DOEpatents

Braden, Jason D.; Harter, Andrew G.; Stinson, Brad J.; Sullivan, Nicholas M.

2016-02-02

The present disclosure provides apparatuses for collecting aerosol samples by ionizing an air sample at different degrees. An air flow is generated through a cavity in which at least one corona wire is disposed and electrically charged to form a corona therearound. At least one grounded sample collection plate is provided downstream of the at least one corona wire so that aerosol ions generated within the corona are deposited on the at least one grounded sample collection plate. A plurality of aerosol samples ionized to different degrees can be generated. The at least one corona wire may be perpendicular to the direction of the flow, or may be parallel to the direction of the flow. The apparatus can include a serial connection of a plurality of stages such that each stage is capable of generating at least one aerosol sample, and the air flow passes through the plurality of stages serially.

Microshutter Array Development for the Multi-Object Spectrograph for the New Generation Space Telescope, and Its Ground-based Demonstrator

NASA Technical Reports Server (NTRS)

Woodgate, Bruce E.; Moseley, Harvey; Fettig, Rainer; Kutyrev, Alexander; Ge, Jian; Fisher, Richard R. (Technical Monitor)

2001-01-01

The 6.5-m NASA/ESA/Canada New Generation Space Telescope to be operated at the L2 Lagrangian point will require a multi-object spectrograph (MOS) operating from 1 to 5 microns. Up to 3000 targets will be selected for simultaneous spectroscopy using a programmable cryogenic (approx. 35K) aperture array, consisting of a mosaic of arrays of micromirrors or microshutters. We describe the current status of the GSFC microshutter array development. The 100 micron square shutters are opened magnetically and latched open or closed electrostatically. Selection will be by two crossed one-dimensional addressing circuits. We will demonstrate the use of a 512 x 512 unit array on a ground-based IR MOS which will cover 0.6 to 5 microns, and operate rapidly to include spectroscopy of gamma ray burst afterglows.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Griswold, M. E., E-mail: mgriswold@trialphaenergy.com; Korepanov, S.; Thompson, M. C.

An end loss analyzer system consisting of electrostatic, gridded retarding-potential analyzers and pyroelectric crystal bolometers was developed to characterize the plasma loss along open field lines to the divertors of C-2U. The system measures the current and energy distribution of escaping ions as well as the total power flux to enable calculation of the energy lost per escaping electron/ion pair. Special care was taken in the construction of the analyzer elements so that they can be directly mounted to the divertor electrode. An attenuation plate at the entrance to the gridded retarding-potential analyzer reduces plasma density by a factor ofmore » 60 to prevent space charge limitations inside the device, without sacrificing its angular acceptance of ions. In addition, all of the electronics for the measurement are isolated from ground so that they can float to the bias potential of the electrode, 2 kV below ground.« less

Perturbations of ionosphere-magnetosphere coupling by powerful VLF emissions from ground-based transmitters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Belov, A. S., E-mail: alexis-belov@yandex.ru; Markov, G. A.; Ryabov, A. O.

The characteristics of the plasma-wave disturbances stimulated in the near-Earth plasma by powerful VLF radiation from ground-based transmitters are investigated. Radio communication VLF transmitters of about 1 MW in power are shown to produce artificial plasma-wave channels (density ducts) in the near-Earth space that originate in the lower ionosphere above the disturbing emission source and extend through the entire ionosphere and magnetosphere of the Earth along the magnetic field lines. Measurements with the onboard equipment of the DEMETER satellite have revealed that under the action of emission from the NWC transmitter, which is one of the most powerful VLF radiomore » transmitters, the generation of quasi-electrostatic (plasma) waves is observed on most of the satellite trajectory along the disturbed magnetic flux tube. This may probably be indicative of stimulated emission of a magnetospheric maser.« less

Evaluation of conductive concrete for anti-static flooring applications

NASA Astrophysics Data System (ADS)

Yehia, Sherif; Qaddoumi, Nasser; Hassan, Mohamed; Swaked, Bassam

2015-04-01

Static electricity, exchange of electrons, and retention of charge between any two materials due to contact and separation are affected by the condition of the materials being nonconductive or insulated from ground. Several work environments, such as electronics industry, hospitals, offices, and computer rooms all require electro-static discharge (ESD) mitigation. Carpet Tile, Carpet Broadloom, Vinyl Tile, Vinyl sheet, Epoxy and Rubber are examples of existing flooring systems in the market. However, each system has its advantages and limitations. Conductive concrete is a relatively new material technology developed to achieve high electrical conductivity and high mechanical strength. The conductive concrete material can be an economical alternative for these ESD flooring systems. In this paper, the effectiveness of conductive concrete as an anti-static flooring system was evaluated. The initial results indicated that the proposed conductive concrete flooring and ground system met the acceptance criteria stated by ASTM F150.

Using hyperdocuments to manage scientific knowledge: the prototype Encyclopedia of Southern Appalachian Forest Ecosystems

Treesearch

Deborah K. Kennard; H. Michael Rauscher; Patricia A. Flebbe; Daniel L. Schmoldt; William G. Hubbard; J. Bryan Jordin; William Milnor

2005-01-01

Despite the overwhelming body of research available on the ecology and management of Southern Appalachian forests, a gap exists between what scientists know and what the management community is able to apply on the ground. Most research knowledge still resides in highly technical, narrowly focused research publications housed in libraries. The internet, combined with...

An instrumental puzzle: the modular integration of AOLI

NASA Astrophysics Data System (ADS)

López, Roberto L.; Velasco, Sergio; Colodro-Conde, Carlos; Valdivia, Juan J. F.; Puga, Marta; Oscoz, Alejandro; Rebolo, Rafael; MacKay, Craig; Pérez-Garrido, Antonio; Rodríguez-Ramos, Luis Fernando; Rodríguez-Ramos, José Manuel M.; King, David; Labadie, Lucas; Muthusubramanian, Balaji; Rodríguez-Coira, Gustavo

2016-08-01

The Adaptive Optics Lucky Imager, AOLI, is an instrument developed to deliver the highest spatial resolution ever obtained in the visible, 20 mas, from ground-based telescopes. In AOLI a new philosophy of instrumental prototyping has been applied, based on the modularization of the subsystems. This modular concept offers maximum flexibility regarding the instrument, telescope or the addition of future developments.

X-band uplink ground systems development: Part 2

NASA Technical Reports Server (NTRS)

Johns, C. E.

1987-01-01

The prototype X-band exciter testing has been completed. Stability and single-sideband phase noise measurements have been made on the X-band exciter signal (7.145-7.235 GHz) and on the coherent X- and S-band receiver test signals (8.4-8.5 GHz and 2.29-2.3 GHz) generated within the exciter equipment. Outputs are well within error budgets.

DIFFUSION IN THE VICINITY OF STANDARD-DESIGN NUCLEAR POWER PLANTS-I. WIND-TUNNEL EVALUATION OF DIFFUSIVE CHARACTERISTICS OF A SIMULATED SUBURBAN NEUTRAL ATMOSPHERIC BOUNDARY LAYER

EPA Science Inventory

A large meteorological wind tunnel was used to simulate a suburban atmospheric boundary layer. The model-prototype scale was 1:300 and the roughness length was approximately 1.0 m full scale. The model boundary layer simulated full scale dispersion from ground-level and elevated ...

Early Synthetic Prototyping: Exploring Designs and Concepts Within Games

DTIC Science & Technology

2014-12-01

UAS unmanned aircraft system UGV unmanned ground vehicle USD(AT&L) Under Secretary of Defense for Acquisition, Technology, and Logistics... unmanned aircraft system (UAS) realm for the wingman concept? The players were familiar with the Marine Corps’ unmanned tactical autonomous control and...UTACCS Unmanned Tactical Autonomous Control and Collaboration System VBIED vehicle borne improvised explosive device VBS2/3 Virtual Battlespace

Demonstrations of LSS active vibration control technology on representative ground-based testbeds

NASA Technical Reports Server (NTRS)

Hyland, David C.; Phillips, Douglas J.; Collins, Emmanuel G., Jr.

1991-01-01

This paper describes two experiments which successfully demonstrate control of flexible structures. The first experiment involved control design and implementation for the ACES structure at NASA Marshall Space Flight Center, while the second experiment was conducted using the Multi-Hex Prototype structure. The paper concludes with some remarks on the lessons learned from conducting these experiments.

CPdock: the complementarity plot for docking of proteins: implementing multi-dielectric continuum electrostatics.

PubMed

Basu, Sankar

2017-12-07

The complementarity plot (CP) is an established validation tool for protein structures, applicable to both globular proteins (folding) as well as protein-protein complexes (binding). It computes the shape and electrostatic complementarities (S m , E m ) for amino acid side-chains buried within the protein interior or interface and plots them in a two-dimensional plot having knowledge-based probabilistic quality estimates for the residues as well as for the whole structure. The current report essentially presents an upgraded version of the plot with the implementation of the advanced multi-dielectric functionality (as in Delphi version 6.2 or higher) in the computation of electrostatic complementarity to make the validation tool physico-chemically more realistic. The two methods (single- and multi-dielectric) agree decently in their resultant E m values, and hence, provisions for both methods have been kept in the software suite. So to speak, the global electrostatic balance within a well-folded protein and/or a well-packed interface seems only marginally perturbed by the choice of different internal dielectric values. However, both from theoretical as well as practical grounds, the more advanced multi-dielectric version of the plot is certainly recommended for potentially producing more reliable results. The report also presents a new methodology and a variant plot, namely CP dock , based on the same principles of complementarity specifically designed to be used in the docking of proteins. The efficacy of the method to discriminate between good and bad docked protein complexes has been tested on a recent state-of-the-art docking benchmark. The results unambiguously indicate that CP dock can indeed be effective in the initial screening phase of a docking scoring pipeline before going into more sophisticated and computationally expensive scoring functions. CP dock has been made available at https://github.com/nemo8130/CPdock . Graphical Abstract An example showing the efficacy of CP dock to be used in the initial screening phase of a protein-protein docking scoring pipeline.

Two-mirror, three-reflection telescopes as candidates for sky surveys in ground and space applications. The MINITRUST: an active optics warping telescope for wide-field astronomy

NASA Astrophysics Data System (ADS)

Viotti, Roberto F.; La Padula, Cesare D.; Vignato, Agostino; Lemaitre, Gerard R.; Montiel, Pierre; Dohlen, Kjetil

2002-12-01

A concept based on a two-mirror, three-reflection telescope has been investigated. Its anastigmatism and flat fielded properties, the compactness and optical performances over 2-2.5 arc deg field of view, make this optical system of high interest for the development of much larger telescopes than with Schmidt designs. The 2MTRT concept is a potential candidate for sky surveys with 2-3 meter class telescopes and particularily well adapted for UV space surveys. Preliminary developments have been carried out with the construction of a 30-cm prototype on Amoretti's design, providing encouraging results. At present, a 45-cm 2MTRT prototype has been realized for ground based sky survey of NEOs, based on active optics (MINITRUST), in order to overcome the difficulty of obtaining three aspherical surfaces. The primary and tertiary lie on the same double vase substrate, and have a rest profile. The hyperbolization is carried out in situ by air depressure. The secondary, in a tulip form substrate, has been hyperbolized by elastic relaxation. The project is planned for operation in 2003.

Optimizing Satellite Communications With Adaptive and Phased Array Antennas

NASA Technical Reports Server (NTRS)

Ingram, Mary Ann; Romanofsky, Robert; Lee, Richard Q.; Miranda, Felix; Popovic, Zoya; Langley, John; Barott, William C.; Ahmed, M. Usman; Mandl, Dan

2004-01-01

A new adaptive antenna array architecture for low-earth-orbiting satellite ground stations is being investigated. These ground stations are intended to have no moving parts and could potentially be operated in populated areas, where terrestrial interference is likely. The architecture includes multiple, moderately directive phased arrays. The phased arrays, each steered in the approximate direction of the satellite, are adaptively combined to enhance the Signal-to-Noise and Interference-Ratio (SNIR) of the desired satellite. The size of each phased array is to be traded-off with the number of phased arrays, to optimize cost, while meeting a bit-error-rate threshold. Also, two phased array architectures are being prototyped: a spacefed lens array and a reflect-array. If two co-channel satellites are in the field of view of the phased arrays, then multi-user detection techniques may enable simultaneous demodulation of the satellite signals, also known as Space Division Multiple Access (SDMA). We report on Phase I of the project, in which fixed directional elements are adaptively combined in a prototype to demodulate the S-band downlink of the EO-1 satellite, which is part of the New Millennium Program at NASA.

Biosphere 2: a prototype project for a permanent and evolving life system for Mars base.

PubMed

Nelson, M; Allen, J P; Dempster, W F

1992-01-01

As part of the ground-based preparation for creating long-term life systems needed for space habitation and settlement, Space Biospheres Ventures (SBV) is undertaking the Biosphere 2 project near Oracle, Arizona. Biosphere 2, currently under construction, is scheduled to commence its operations in 1991 with a two-year closure period with a crew of eight people. Biosphere 2 is a facility which will be essentialy materially-closed to exchange with the outside environment. It is open to information and energy flow. Biosphere 2 is designed to achieve a complex life-support system by the integration of seven areas or "biomes"--rainforest, savannah, desert, marsh, ocean, intensive agriculture and human habitat. Unique bioregenerative technologies, such as soil bed reactors for air purification, aquatic waste processing systems, real-time analytic systems and complex computer monitoring and control systems are being developed for the Biosphere 2 project. Its operation should afford valuable insight into the functioning of complex life systems necessary for long-term habitation in space. It will serve as an experimental ground-based prototype and testbed for the stable, permanent life systems needed for human exploration of Mars.

A unified engineering model of the first stroke in downward negative lightning

NASA Astrophysics Data System (ADS)

Nag, Amitabh; Rakov, Vladimir A.

2016-03-01

Each stroke in a negative cloud-to-ground lightning flash is composed of downward leader and upward return stroke processes, which are usually modeled individually. The first stroke leader is stepped and starts with preliminary breakdown (PB) which is often viewed as a separate process. We present the first unified engineering model for computing the electric field produced by a sequence of PB, stepped leader, and return stroke processes, serving to transport negative charge to ground. We assume that a negatively charged channel extends downward in a stepped fashion during both the PB and leader stages. Each step involves a current wave that propagates upward along the newly formed channel section. Once the leader attaches to ground, an upward propagating return stroke neutralizes the charge deposited along the channel. Model-predicted electric fields are in reasonably good agreement with simultaneous measurements at both near (hundreds of meters, electrostatic field component is dominant) and far (tens of kilometers, radiation field component is dominant) distances from the lightning channel. Relations between the features of computed electric field waveforms and model input parameters are examined. It appears that peak currents associated with PB pulses are similar to return stroke peak currents, and the observed variation of electric radiation field peaks produced by leader steps at different heights above ground is influenced by the ground corona space charge.

Regolith Volatile Recovery at Simulated Lunar Environments

NASA Technical Reports Server (NTRS)

Kleinhenz, Julie; Paulsen, Gale; Zacny, Kris; Schmidt, Sherry; Boucher, Dale

2016-01-01

Lunar Polar Volatiles: Permanently shadowed craters at the lunar poles contain water, 5 wt according to LCROSS. Interest in water for ISRU applications. Desire to ground truth water using surface prospecting e.g. Resource Prospector and RESOLVE. How to access subsurface water resources and accurately measure quantity. Excavation operations and exposure to lunar environment may affect the results. Volatile capture tests: A series a ground based dirty thermal vacuum tests are being conducted to better understand the subsurface sampling operations. Sample removal and transfer. Volatiles loss during sampling operations. Concept of operations, Instrumentation. This presentation is a progress report on volatiles capture results from these tests with lunar polar drill prototype hardware.

Hybrid Ground Station Technology for RF and Optical Communication Links

NASA Technical Reports Server (NTRS)

Davarian, Faramaz; Hoppe, D.; Charles, J.; Vilnrotter, V.; Sehic, A.; Hanson, T.; Gam, E.

2012-01-01

To support future enhancements of NASA's deep space and planetary communications and tracking services, the Jet Propulsion Laboratory is developing a hybrid ground station that will be capable of simultaneously supporting RF and optical communications. The main reason for adding optical links to the existing RF links is to significantly increase the capacity of deep space communications in support of future solar system exploration. It is envisioned that a mission employing an optical link will also use an RF link for telemetry and emergency purposes, hence the need for a hybrid ground station. A hybrid station may also reduce operations cost by requiring fewer staff than would be required to operate two stations. A number of approaches and techniques have been examined. The most promising ones have been prototyped for field examination and validation.

Space Infrared Telescope Facility (SIRTF) - Operations concept. [decreasing development and operations cost

NASA Technical Reports Server (NTRS)

Miller, Richard B.

1992-01-01

The development and operations costs of the Space IR Telescope Facility (SIRTF) are discussed in the light of minimizing total outlays and optimizing efficiency. The development phase cannot extend into the post-launch segment which is planned to only support system verification and calibration followed by operations with a 70-percent efficiency goal. The importance of reducing the ground-support staff is demonstrated, and the value of the highly sensitive observations to the general astronomical community is described. The Failure Protection Algorithm for the SIRTF is designed for the 5-yr lifetime and the continuous venting of cryogen, and a science driven ground/operations system is described. Attention is given to balancing cost and performance, prototyping during the development phase, incremental development, the utilization of standards, and the integration of ground system/operations with flight system integration and test.

Nucleation of Quantized Vortices from Rotating Superfluid Drops

NASA Technical Reports Server (NTRS)

Donnelly, Russell J.

2001-01-01

The long-term goal of this project is to study the nucleation of quantized vortices in helium II by investigating the behavior of rotating droplets of helium II in a reduced gravity environment. The objective of this ground-based research grant was to develop new experimental techniques to aid in accomplishing that goal. The development of an electrostatic levitator for superfluid helium, described below, and the successful suspension of charged superfluid drops in modest electric fields was the primary focus of this work. Other key technologies of general low temperature use were developed and are also discussed.

Plasma heating for containerless and microgravity materials processing

NASA Technical Reports Server (NTRS)

Leung, Emily W. (Inventor); Man, Kin F. (Inventor)

1994-01-01

A method for plasma heating of levitated samples to be used in containerless microgravity processing is disclosed. A sample is levitated by electrostatic, electromagnetic, aerodynamic, or acoustic systems, as is appropriate for the physical properties of the particular sample. The sample is heated by a plasma torch at atmospheric pressure. A ground plate is provided to help direct the plasma towards the sample. In addition, Helmholtz coils are provided to produce a magnetic field that can be used to spiral the plasma around the sample. The plasma heating system is oriented such that it does not interfere with the levitation system.

Comparison of Satellite based Ion Density Measurements with Digisonde electron density measurements

NASA Astrophysics Data System (ADS)

Wilson, G.; Balthazor, R. L.; Reinisch, B. W.; McHarg, M.; Maldonado, C.

2017-12-01

The integrated Miniaturized Electrostatic Analyzer (IMESA) flying on the STPSat-3 satellite has collected more than 3 years of ion density data. This instrument is the first in a constellation of up to 6 instruments. We plan on integrating the data from all IMESAs into an approiate ionospheric model. OUr first step is to validate the IMESA data and calibrate the instrument. In this presentation we discuss our process for preparing IMESA data and comparing it to ground based measurements. Lastly, we present a number of comparisons between IMESA ion density measurements and digisonde electron density measurements.

Langmuir probe surveys of an arcjet exhaust

NASA Technical Reports Server (NTRS)

Zana, Lynnette M.

1987-01-01

Electrostatic (Langmuir) probes of both spherical and cylindrical geometry have been used to obtain electron number density and temperature in the exhaust of a laboratory arcjet. The arcjet thruster operated on nitrogen and hydrogen mixtures to simulate fully decomposed hydrazine in a vacuum environment with background pressures less than 0.05 Pa. The exhaust appears to be only slightly ionized (less than 1 percent) with local plasma potentials near facility ground. The current-voltage characteristics of the probes indicate a Maxwellian temperature distribution. Plume data are presented as a function of arcjet operating conditions and also position in the exhaust.

Sferics

NASA Technical Reports Server (NTRS)

Pierce, E. T.

1969-01-01

The properties of sferics (the electric and magnetic fields generated by electrified clouds and lightning flashes) are briefly surveyed; the source disturbance and the influence of propagation being examined. Methods of observing sferics and their meteorological implications are discussed. It is concluded that close observations of electrostatic and radiation fields are very informative, respectively, upon the charge distribution and spark processes in a cloud; that ground-level sferics stations can accurately locate the positions of individual lightning flashes and furnish valuable knowledge on the properties of the discharges; but that satellite measurements only provide general information on the level of thundery activity over large geographical regions.

Ground operations demonstration unit for liquid hydrogen initial test results

NASA Astrophysics Data System (ADS)

Notardonato, W. U.; Johnson, W. L.; Swanger, A. M.; Tomsik, T.

2015-12-01

NASA operations for handling cryogens in ground support equipment have not changed substantially in 50 years, despite major technology advances in the field of cryogenics. NASA loses approximately 50% of the hydrogen purchased because of a continuous heat leak into ground and flight vessels, transient chill down of warm cryogenic equipment, liquid bleeds, and vent losses. NASA Kennedy Space Center (KSC) needs to develop energy-efficient cryogenic ground systems to minimize propellant losses, simplify operations, and reduce cost associated with hydrogen usage. The GODU LH2 project has designed, assembled, and started testing of a prototype storage and distribution system for liquid hydrogen that represents an advanced end-to-end cryogenic propellant system for a ground launch complex. The project has multiple objectives including zero loss storage and transfer, liquefaction of gaseous hydrogen, and densification of liquid hydrogen. The system is unique because it uses an integrated refrigeration and storage system (IRAS) to control the state of the fluid. This paper will present and discuss the results of the initial phase of testing of the GODU LH2 system.

Ground Operations Demonstration Unit for Liquid Hydrogen Initial Test Results

NASA Technical Reports Server (NTRS)

Notardonato, W. U.; Johnson, W. L.; Swanger, A. M.; Tomsik, T.

2015-01-01

NASA operations for handling cryogens in ground support equipment have not changed substantially in 50 years, despite major technology advances in the field of cryogenics. NASA loses approximately 50% of the hydrogen purchased because of a continuous heat leak into ground and flight vessels, transient chill down of warm cryogenic equipment, liquid bleeds, and vent losses. NASA Kennedy Space Center (KSC) needs to develop energy-efficient cryogenic ground systems to minimize propellant losses, simplify operations, and reduce cost associated with hydrogen usage. The GODU LH2 project has designed, assembled, and started testing of a prototype storage and distribution system for liquid hydrogen that represents an advanced end-to-end cryogenic propellant system for a ground launch complex. The project has multiple objectives including zero loss storage and transfer, liquefaction of gaseous hydrogen, and densification of liquid hydrogen. The system is unique because it uses an integrated refrigeration and storage system (IRAS) to control the state of the fluid. This paper will present and discuss the results of the initial phase of testing of the GODU LH2 system.

Prototype Vent Gas Heat Exchanger for Exploration EVA - Performance and Manufacturing Characteristics

NASA Technical Reports Server (NTRS)

Quinn, Gregory J.; Strange, Jeremy; Jennings, Mallory

2013-01-01

NASA is developing new portable life support system (PLSS) technologies, which it is demonstrating in an unmanned ground based prototype unit called PLSS 2.0. One set of technologies within the PLSS provides suitable ventilation to an astronaut while on an EVA. A new component within the ventilation gas loop is a liquid-to-gas heat exchanger to transfer excess heat from the gas to the thermal control system s liquid coolant loop. A unique bench top prototype heat exchanger was built and tested for use in PLSS 2.0. The heat exchanger was designed as a counter-flow, compact plate fin type using stainless steel. Its design was based on previous compact heat exchangers manufactured by United Technologies Aerospace Systems (UTAS), but was half the size of any previous heat exchanger model and one third the size of previous liquid-to-gas heat exchangers. The prototype heat exchanger was less than 40 cubic inches and weighed 2.57 lb. Performance of the heat exchanger met the requirements and the model predictions. The water side and gas side pressure drops were less 0.8 psid and 0.5 inches of water, respectively, and an effectiveness of 94% was measured at the nominal air side pressure of 4.1 psia.

YF-22 in flight (US AF photo)

NASA Technical Reports Server (NTRS)

1990-01-01

The YF-22, prototype aircraft for the Air Force's F-22 fighter, cruises over the desert on a flight for the Air Force. It was never involved in any programs with Dryden. The United States Air Force announced the demonstration/validation phase contractors selection for the Advanced Tactical Fighter (ATF) program October 31, 1986. These contractor programs were the Lockheed YF-22 and the Northrop YF-23; each produced two prototypes and ground-based avionics testbeds. First flights of all four prototypes occured in 1990. The YF-22 was first flown on Sept. 29, 1990. The YF-22 was powered by two General Electric YF120-GE-100 engines. The final design, the F-22, was flown sometime in May 1997. The F-22 is capable of efficient supersonic operation without afterburner use (supercruise). Lockheed teamed with General Dynamics (Fort Worth) and Boeing Military Airplanes to produce two YF-22 prototypes, civil registrations N22YF (with GE YF120) and N22YX (P&W YF119). N22YF rolled out at Palmdale August 29, 1990; first flight/ferry to Edwards AFB September 29, 1990; first air refuelling (11th sortie) October 26, 1990; thrust vectoring in flight November 15, 1990; achieved Mach 1.8 December 26, 1990. Flight test demonstrations included `supercruise' flight in excess of Mach 1.58 without afterburner.

A compact linear accelerator based on a scalable microelectromechanical-system RF-structure

DOE PAGES

Persaud, A.; Ji, Q.; Feinberg, E.; ...

2017-06-08

Here, a new approach for a compact radio-frequency (RF) accelerator structure is presented. The new accelerator architecture is based on the Multiple Electrostatic Quadrupole Array Linear Accelerator (MEQALAC) structure that was first developed in the 1980s. The MEQALAC utilized RF resonators producing the accelerating fields and providing for higher beam currents through parallel beamlets focused using arrays of electrostatic quadrupoles (ESQs). While the early work obtained ESQs with lateral dimensions on the order of a few centimeters, using a printed circuit board (PCB), we reduce the characteristic dimension to the millimeter regime, while massively scaling up the potential number ofmore » parallel beamlets. Using Microelectromechanical systems scalable fabrication approaches, we are working on further red ucing the characteristic dimension to the sub-millimeter regime. The technology is based on RF-acceleration components and ESQs implemented in the PCB or silicon wafers where each beamlet passes through beam apertures in the wafer. The complete accelerator is then assembled by stacking these wafers. This approach has the potential for fast and inexpensive batch fabrication of the components and flexibility in system design for application specific beam energies and currents. For prototyping the accelerator architecture, the components have been fabricated using the PCB. In this paper, we present proof of concept results of the principal components using the PCB: RF acceleration and ESQ focusing. Finally, ongoing developments on implementing components in silicon and scaling of the accelerator technology to high currents and beam energies are discussed.« less

A compact linear accelerator based on a scalable microelectromechanical-system RF-structure

NASA Astrophysics Data System (ADS)

Persaud, A.; Ji, Q.; Feinberg, E.; Seidl, P. A.; Waldron, W. L.; Schenkel, T.; Lal, A.; Vinayakumar, K. B.; Ardanuc, S.; Hammer, D. A.

2017-06-01

A new approach for a compact radio-frequency (RF) accelerator structure is presented. The new accelerator architecture is based on the Multiple Electrostatic Quadrupole Array Linear Accelerator (MEQALAC) structure that was first developed in the 1980s. The MEQALAC utilized RF resonators producing the accelerating fields and providing for higher beam currents through parallel beamlets focused using arrays of electrostatic quadrupoles (ESQs). While the early work obtained ESQs with lateral dimensions on the order of a few centimeters, using a printed circuit board (PCB), we reduce the characteristic dimension to the millimeter regime, while massively scaling up the potential number of parallel beamlets. Using Microelectromechanical systems scalable fabrication approaches, we are working on further reducing the characteristic dimension to the sub-millimeter regime. The technology is based on RF-acceleration components and ESQs implemented in the PCB or silicon wafers where each beamlet passes through beam apertures in the wafer. The complete accelerator is then assembled by stacking these wafers. This approach has the potential for fast and inexpensive batch fabrication of the components and flexibility in system design for application specific beam energies and currents. For prototyping the accelerator architecture, the components have been fabricated using the PCB. In this paper, we present proof of concept results of the principal components using the PCB: RF acceleration and ESQ focusing. Ongoing developments on implementing components in silicon and scaling of the accelerator technology to high currents and beam energies are discussed.

A compact linear accelerator based on a scalable microelectromechanical-system RF-structure.

PubMed

Persaud, A; Ji, Q; Feinberg, E; Seidl, P A; Waldron, W L; Schenkel, T; Lal, A; Vinayakumar, K B; Ardanuc, S; Hammer, D A

2017-06-01

A new approach for a compact radio-frequency (RF) accelerator structure is presented. The new accelerator architecture is based on the Multiple Electrostatic Quadrupole Array Linear Accelerator (MEQALAC) structure that was first developed in the 1980s. The MEQALAC utilized RF resonators producing the accelerating fields and providing for higher beam currents through parallel beamlets focused using arrays of electrostatic quadrupoles (ESQs). While the early work obtained ESQs with lateral dimensions on the order of a few centimeters, using a printed circuit board (PCB), we reduce the characteristic dimension to the millimeter regime, while massively scaling up the potential number of parallel beamlets. Using Microelectromechanical systems scalable fabrication approaches, we are working on further reducing the characteristic dimension to the sub-millimeter regime. The technology is based on RF-acceleration components and ESQs implemented in the PCB or silicon wafers where each beamlet passes through beam apertures in the wafer. The complete accelerator is then assembled by stacking these wafers. This approach has the potential for fast and inexpensive batch fabrication of the components and flexibility in system design for application specific beam energies and currents. For prototyping the accelerator architecture, the components have been fabricated using the PCB. In this paper, we present proof of concept results of the principal components using the PCB: RF acceleration and ESQ focusing. Ongoing developments on implementing components in silicon and scaling of the accelerator technology to high currents and beam energies are discussed.

Back-gated graphene anode for more efficient thermionic energy converters

DOE PAGES

Yuan, Hongyuan; Riley, Daniel C.; Shen, Zhi-Xun; ...

2016-12-15

Thermionic energy converters (TECs) are a direct heat-to-electricity conversion technology with great potential for high efficiency and scalability. However, space charge barrier in the inter-electrode gap and high anode work function are major obstacles toward realizing high efficiency. Here, we demonstrate for the first time a prototype TEC using a back-gated graphene anode, a barium dispenser cathode, and a controllable inter-electrode gap as small as 17 µm, which simultaneously addresses these two obstacles. This leads to an electronic conversion efficiency of 9.8% at cathode temperature of 1000 °C, the highest reported by far. We first demonstrate that electrostatic gating ofmore » graphene by a 20 nm HfO 2 dielectric layer changes the graphene anode work function by 0.63 eV, as observed from the current-voltage characteristics of the TEC. Next, we show that the efficiency increases by a factor of 30.6 by reducing the gap from 1 mm down to 17 µm, after a mono-layer of Ba is deposited on graphene by the dispenser cathode. Lastlu, we show that electrostatic gating of graphene further reduces the graphene work function from 1.85 to 1.69 eV, leading to an additional 67% enhancement in TEC efficiency. Note that the overall efficiency using the back-gated graphene anode is 6.7 times higher compared with that of a TEC with a tungsten anode and the same inter-electrode gap.« less

Preliminary Results of a Microgravity Investigation to Measure Net Charge on Granular Materials

NASA Technical Reports Server (NTRS)

Green, Robert D.; Myers, Jerry G.; Hansen, Bonnie L.

2003-01-01

Accurate characterization of the electrostatic charge on granular materials has typically been limited to materials with diameters on the order of 10 microns and below due to high settling velocities of larger particles. High settling velocities limit both the time and the acceptable uncertainty with which a measurement can be made. A prototype device has been developed at NASA Glenn Research Center (GRC) to measure coulombic charge on individual particles of granular materials that are 50 to 500 microns in diameter. This device, a novel extension of Millikan's classic oil drop experiment, utilizes the NASA GRC 2.2 second drop tower to extend the range of electrostatic charge measurements to accommodate moderate size granular materials. A dielectric material with a nominal grain diameter between 1.06 and 250 microns was tribocharged using a dry gas jet, suspended in a 5x10x10 cm enclosure during a 2.2 second period of microgravity and exposed to a known electric field. The response was recorded on video and post processed to allow tracking of individual particles. By determining the particle trajectory and velocity, estimates of the coulombic charge were made. Over 30 drops were performed using this technique and the analysis showed that first order approximations of coulombic charge could successfully be obtained, with the mean charge of 3.4E-14 coulombs measured for F-75 Ottawa quartz sand. Additionally, the measured charge showed a near-Gaussian distribution, with a standard deviation of 2.14E -14 coulombs.

Drift mode accelerometry for spaceborne gravity measurements

NASA Astrophysics Data System (ADS)

Conklin, John W.

2015-11-01

A drift mode accelerometer is a precision instrument for spacecraft that overcomes much of the acceleration noise and readout dynamic range limitations of traditional electrostatic accelerometers. It has the potential of achieving acceleration noise performance similar to that of drag-free systems over a restricted frequency band without the need for external drag-free control or continuous spacecraft propulsion. Like traditional accelerometers, the drift mode accelerometer contains a high-density test mass surrounded by an electrode housing, which can control and sense all six degrees of freedom of the test mass. Unlike traditional accelerometers, the suspension system is operated with a low duty cycle so that the limiting suspension force noise only acts over brief, known time intervals, which can be neglected in the data analysis. The readout is performed using a laser interferometer which is immune to the dynamic range limitations of even the best voltage references typically used to determine the inertial acceleration of electrostatic accelerometers. The drift mode accelerometer is a novel offshoot of the like-named operational mode of the LISA Pathfinder spacecraft, in which its test mass suspension system is cycled on and off to estimate the acceleration noise associated with the front-end electronics. This paper presents the concept of a drift mode accelerometer, describes the operation of such a device, develops models for its performance with respect to non-drag-free satellite geodesy and gravitational wave missions, and discusses plans for testing the performance of a prototype sensor in the laboratory using torsion pendula.

Back-gated graphene anode for more efficient thermionic energy converters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yuan, Hongyuan; Riley, Daniel C.; Shen, Zhi-Xun

Thermionic energy converters (TECs) are a direct heat-to-electricity conversion technology with great potential for high efficiency and scalability. However, space charge barrier in the inter-electrode gap and high anode work function are major obstacles toward realizing high efficiency. Here, we demonstrate for the first time a prototype TEC using a back-gated graphene anode, a barium dispenser cathode, and a controllable inter-electrode gap as small as 17 µm, which simultaneously addresses these two obstacles. This leads to an electronic conversion efficiency of 9.8% at cathode temperature of 1000 °C, the highest reported by far. We first demonstrate that electrostatic gating ofmore » graphene by a 20 nm HfO 2 dielectric layer changes the graphene anode work function by 0.63 eV, as observed from the current-voltage characteristics of the TEC. Next, we show that the efficiency increases by a factor of 30.6 by reducing the gap from 1 mm down to 17 µm, after a mono-layer of Ba is deposited on graphene by the dispenser cathode. Lastlu, we show that electrostatic gating of graphene further reduces the graphene work function from 1.85 to 1.69 eV, leading to an additional 67% enhancement in TEC efficiency. Note that the overall efficiency using the back-gated graphene anode is 6.7 times higher compared with that of a TEC with a tungsten anode and the same inter-electrode gap.« less

Encapsulation of Autoinducer Sensing Reporter Bacteria in Reinforced Alginate-Based Microbeads.

PubMed

Li, Ping; Müller, Mareike; Chang, Matthew Wook; Frettlöh, Martin; Schönherr, Holger

2017-07-12

Quorum sensing, in which bacteria communities use signaling molecules for inter- and intracellular communication, has been intensively studied in recent decades. In order to fabricate highly sensitive easy-to-handle point of care biosensors that detect quorum sensing molecules, we have developed, as is reported here, reporter bacteria loaded alginate-methacrylate (alginate-MA) hydrogel beads. The alginate-MA beads, which were obtained by electrostatic extrusion, were reinforced by photo-cross-linking to increase stability and thereby to reduce bacteria leaching. In these beads the genetically engineered fluorescent reporter bacterium Escherichia coli pTetR-LasR-pLuxR-GFP (E. coli pLuxR-GFP) was encapsulated, which responds to the autoinducer N-(3-oxododecanoyl)homoserine lactone secreted by Pseudomonas aeruginosa. After encapsulation in alginate-MA hydrogel beads with diameters in the range of 100-300 μm that were produced by an electrostatic extrusion method and rapid photo-cross-linking, the E. coli pLuxR-GFP were found to possess a high degree of viability and sensing activity. The encapsulated bacteria could proliferate inside the hydrogel beads, when exposed to bacteria culture medium. In media containing the autoinducer N-(3-oxododecanoyl)homoserine lactone, the encapsulated reporter bacteria responded with a strong fluorescence signal due to an increased green fluorescent protein (GFP) expression. A prototype dipstick type sensor developed here underlines the potential of encapsulation of viable and functional reporter bacteria inside reinforced alginate-methacrylate hydrogel beads for whole cell sensors for bacteria detection.

Development of Individually Addressable Micro-Mirror-Arrays for Space Applications

NASA Technical Reports Server (NTRS)

Dutta, Sanghamitra B.; Ewin, Audrey J.; Jhabvala, Murzy; Kotecki, Carl A.; Kuhn, Jonathan L.; Mott, D. Brent

2000-01-01

We have been developing a 32 x 32 prototype array of individually addressable Micro-Mirrors capable of operating at cryogenic temperature for Earth and Space Science applications. Micro-Mirror-Array technology has the potential to revolutionize imaging and spectroscopy systems for NASA's missions of the 21st century. They can be used as programmable slits for the Next Generation Space Telescope, as smart sensors for a steerable spectrometer, as neutral density filters for bright scene attenuation etc. The, entire fabrication process is carried out in the Detector Development Laboratory at NASA, GSFC. The fabrication process is low temperature compatible and involves integration of conventional CMOS technology and surface micro-machining used in MEMS. Aluminum is used as the mirror material and is built on a silicon substrate containing the CMOS address circuit. The mirrors are 100 microns x l00 microns in area and deflect by +/- 10 deg induced by electrostatic actuation between two parallel plate capacitors. A pair of thin aluminum torsion straps allow the mirrors to tilt. Finite-element-analysis and closed form solutions using electrostatic and mechanical torque for mirror operation were developed and the results were compared with laboratory performance. The results agree well both at room temperature and at cryogenic temperature. The development demonstrates the first cryogenic operation of two-dimensional Micro-Mirrors with bi-state operation. Larger arrays will be developed meeting requirements for different science applications. Theoretical analysis, fabrication process, laboratory test results and different science applications will be described in detail.

Automated ground-water monitoring with Robowell: case studies and potential applications

NASA Astrophysics Data System (ADS)

Granato, Gregory E.; Smith, Kirk P.

2002-02-01

Robowell is an automated system and method for monitoring ground-water quality. Robowell meets accepted manual- sampling protocols without high labor and laboratory costs. Robowell periodically monitors and records water-quality properties and constituents in ground water by pumping a well or multilevel sampler until one or more purge criteria have been met. A record of frequent water-quality measurements from a monitoring site can indicate changes in ground-water quality and can provide a context for the interpretation of laboratory data from discrete samples. Robowell also can communicate data and system performance through a remote communication link. Remote access to ground-water data enables the user to monitor conditions and optimize manual sampling efforts. Six Robowell prototypes have successfully monitored ground-water quality during all four seasons of the year under different hydrogeologic conditions, well designs, and geochemical environments. The U.S. Geological Survey is seeking partners for research with robust and economical water-quality monitoring instruments designed to measure contaminants of concern in conjunction with the application and commercialization of the Robowell technology. Project publications and information about technology transfer opportunities are available on the Internet at URL http://ma.water.usgs.gov/automon/

Automated ground-water monitoring with robowell-Case studies and potential applications

USGS Publications Warehouse

Granato, G.E.; Smith, K.P.; ,

2001-01-01

Robowell is an automated system and method for monitoring ground-water quality. Robowell meets accepted manual-sampling protocols without high labor and laboratory costs. Robowell periodically monitors and records water-quality properties and constituents in ground water by pumping a well or multilevel sampler until one or more purge criteria have been met. A record of frequent water-quality measurements from a monitoring site can indicate changes in ground-water quality and can provide a context for the interpretation of laboratory data from discrete samples. Robowell also can communicate data and system performance through a remote communication link. Remote access to ground-water data enables the user to monitor conditions and optimize manual sampling efforts. Six Robowell prototypes have successfully monitored ground-water quality during all four seasons of the year under different hydrogeologic conditions, well designs, and geochemical environments. The U.S. Geological Survey is seeking partners for research with robust and economical water-quality monitoring instruments designed to measure contaminants of concern in conjunction with the application and commercialization of the Robowell technology. Project publications and information about technology transfer opportunities are available on the Internet at URL http://ma.water.usgs.gov/automon/.

Cryogenic fluid management experiment

NASA Technical Reports Server (NTRS)

Eberhardt, R. N.; Bailey, W. J.; Fester, D. A.

1981-01-01

The cryogenic fluid management experiment (CFME), designed to characterize subcritical liquid hydrogen storage and expulsion in the low-q space environment, is discussed. The experiment utilizes a fine mesh screen fluid management device to accomplish gas-free liquid expulsion and a thermodynamic vent system to intercept heat leak and control tank pressure. The experiment design evolved from a single flight prototype to provision for a multimission (up to 7) capability. A detailed design of the CFME, a dynamic test article, and dedicated ground support equipment were generated. All materials and parts were identified, and components were selected and specifications prepared. Long lead titanium pressurant spheres and the flight tape recorder and ground reproduce unit were procured. Experiment integration with the shuttle orbiter, Spacelab, and KSC ground operations was coordinated with the appropriate NASA centers, and experiment interfaces were defined. Phase 1 ground and flight safety reviews were conducted. Costs were estimated for fabrication and assembly of the CFME, which will become the storage and supply tank for a cryogenic fluid management facility to investigate fluid management in space.

Construction of Source Model of Huge Subduction Earthquakes for Strong Ground Motion Prediction

NASA Astrophysics Data System (ADS)

Iwata, T.; Asano, K.; Kubo, H.

2013-12-01

It is a quite important issue for strong ground motion prediction to construct the source model of huge subduction earthquakes. Iwata and Asano (2012, AGU) summarized the scaling relationships of large slip area of heterogeneous slip model and total SMGA sizes on seismic moment for subduction earthquakes and found the systematic change between the ratio of SMGA to the large slip area and the seismic moment. They concluded this tendency would be caused by the difference of period range of source modeling analysis. In this paper, we try to construct the methodology of construction of the source model for strong ground motion prediction for huge subduction earthquakes. Following to the concept of the characterized source model for inland crustal earthquakes (Irikura and Miyake, 2001; 2011) and intra-slab earthquakes (Iwata and Asano, 2011), we introduce the proto-type of the source model for huge subduction earthquakes and validate the source model by strong ground motion modeling.

PCE: web tools to compute protein continuum electrostatics

PubMed Central

Miteva, Maria A.; Tufféry, Pierre; Villoutreix, Bruno O.

2005-01-01

PCE (protein continuum electrostatics) is an online service for protein electrostatic computations presently based on the MEAD (macroscopic electrostatics with atomic detail) package initially developed by D. Bashford [(2004) Front Biosci., 9, 1082–1099]. This computer method uses a macroscopic electrostatic model for the calculation of protein electrostatic properties, such as pKa values of titratable groups and electrostatic potentials. The MEAD package generates electrostatic energies via finite difference solution to the Poisson–Boltzmann equation. Users submit a PDB file and PCE returns potentials and pKa values as well as color (static or animated) figures displaying electrostatic potentials mapped on the molecular surface. This service is intended to facilitate electrostatics analyses of proteins and thereby broaden the accessibility to continuum electrostatics to the biological community. PCE can be accessed at . PMID:15980492

New tools for investigating student learning in upper-division electrostatics

NASA Astrophysics Data System (ADS)

Wilcox, Bethany R.

Student learning in upper-division physics courses is a growing area of research in the field of Physics Education. Developing effective new curricular materials and pedagogical techniques to improve student learning in upper-division courses requires knowledge of both what material students struggle with and what curricular approaches help to overcome these struggles. To facilitate the course transformation process for one specific content area --- upper-division electrostatics --- this thesis presents two new methodological tools: (1) an analytical framework designed to investigate students' struggles with the advanced physics content and mathematically sophisticated tools/techniques required at the junior and senior level, and (2) a new multiple-response conceptual assessment designed to measure student learning and assess the effectiveness of different curricular approaches. We first describe the development and theoretical grounding of a new analytical framework designed to characterize how students use mathematical tools and techniques during physics problem solving. We apply this framework to investigate student difficulties with three specific mathematical tools used in upper-division electrostatics: multivariable integration in the context of Coulomb's law, the Dirac delta function in the context of expressing volume charge densities, and separation of variables as a technique to solve Laplace's equation. We find a number of common themes in students' difficulties around these mathematical tools including: recognizing when a particular mathematical tool is appropriate for a given physics problem, mapping between the specific physical context and the formal mathematical structures, and reflecting spontaneously on the solution to a physics problem to gain physical insight or ensure consistency with expected results. We then describe the development of a novel, multiple-response version of an existing conceptual assessment in upper-division electrostatics courses. The goal of this new version is to provide an easily-graded electrostatics assessment that can potentially be implemented to investigate student learning on a large scale. We show that student performance on the new multiple-response version exhibits a significant degree of consistency with performance on the free-response version, and that it continues to provide significant insight into student reasoning and student difficulties. Moreover, we demonstrate that the new assessment is both valid and reliable using data from upper-division physics students at multiple institutions. Overall, the work described in this thesis represents a significant contribution to the methodological tools available to researchers and instructors interested in improving student learning at the upper-division level.

The Rocket Electric Field Sounding (REFS) program: Prototype design and successful first launch

NASA Astrophysics Data System (ADS)

Willett, J. C.; Curtis, D. C.; Driesman, A. R.; Longstreth, R. K.; Rison, W.; Winn, W. P.; Jones, J. J.

1992-01-01

The motivation, design, and successful first flight of a sounding rocket to measure profiles of vector electrostatic field in the lower troposphere are described. The design employs eight shutter field mills amd a corona-charging system in a manner similar to aircraft previously instrumented for the measurement of electric fields. A rocket offers significant advantages over an aircraft in simplicity and calibration. A single cylindrical rotor covering most of the payload acts as the shutter for all eight mills in this design. The cylindrical symmetry and circular cross sections of the vehicle facilitate straightforward calibration. Also included in the payload are a pressure sensor, a longitudinal accelerometer, a transverse magnometer, and a novel cloud-penetration detector. A fair-weather test flight at the NASA Wallops Flight Facility demonstrated the workability of the basic design and identified a few necessary modifications.

Long-Range Interactions Restrict Water Transport in Pyrophyllite Interlayers

DOE PAGES

Zarzycki, Piotr; Gilbert, Benjamin

2016-04-27

Water diffusion within smectite clay interlayers is reduced by confinement and hence is highly determined by the interlayer spacings that are adopted during swelling. However, a molecular understanding of the short-and long-range forces governing interlayer water structure and dynamics is lacking. Using molecular dynamics simulations of water intercalated between pyrophyllite (smectite prototype) layers we provide a detailed picture of the variation of interlayered water mobility accompanying smectite expansion. Subtle changes in hydrogen bond network structure cause significant changes in water mobility that is greater for stable hydration states and reduced for intermediate separations. By studying pyrophyllite with and without externalmore » water we reveal that long-range electrostatic forces apply a restraining effect upon interlayer water mobility. Our findings are relevant for broad range of confining nanostructures with walls thin enough to permit long-range interactions that could affect the mobility of confined solvent molecules and solute species.« less

Miniaturized Environmental Monitoring Instrumentation

DOE Office of Scientific and Technical Information (OSTI.GOV)

C. B. Freidhoff

1997-09-01

The objective of the Mass Spectrograph on a Chip (MSOC) program is the development of a miniature, multi-species gas sensor fabricated using silicon micromachining technology which will be orders of magnitude smaller and lower power consumption than a conventional mass spectrometer. The sensing and discrimination of this gas sensor are based on an ionic mass spectrograph, using magnetic and/or electrostatic fields. The fields cause a spatial separation of the ions according to their respective mass-to-charge ratio. The fabrication of this device involves the combination of microelectronics with micromechanically built sensors and, ultimately, vacuum pumps. The prototype of a chemical sensormore » would revolutionize the method of performing environmental monitoring for both commercial and government applications. The portable unit decided upon was the miniaturized gas chromatograph with a mass spectrometer detector, referred to as a GC/MS in the analytical marketplace.« less

Design of components for growing higher plants in space

NASA Technical Reports Server (NTRS)

1988-01-01

The overall goal of this project is to design unique systems and components for growing higher plants in microgravity during long-term space missions (Mars and beyond). Specific design tasks were chosen to contribute to and supplement NASA's Controlled Ecological Life Support System (CELSS) project. Selected tasks were automated seeding of plants, plant health sensing, and food processing. Prototype systems for planting both germinated and nongerminated seeds were fabricated and tested. Water and air pressure differences and electrostatic fields were used to trap seeds for separation and transport for planting. An absorption spectrometer was developed to measure chlorophyll levels in plants as an early warning of plant health problems. In the area of food processing, a milling system was created using high-speed rotating blades which were aerodynamically configured to produce circulation and retractable to prevent leakage. The project produced significant results having substantial benefit to NASA. It also provided an outstanding learning experience for the students involved.

Charged particle concepts for fog dispersion

NASA Technical Reports Server (NTRS)

Frost, W.; Collins, F. G.; Koepf, D.

1981-01-01

Charged particle techniques hold promise for dispersing warm fog in the terminal area of commercial airports. This report focuses on features of the charged particle technique which require further study. The basic physical principles of the technique and the major verification experiments carried out in the past are described. The fundamentals of the nozzle operation are given. The nozzle characteristics and the theory of particle charging in the nozzle are discussed, including information from extensive literature on electrostatic precipitation relative to environmental pollution control and a description of some preliminary reported analyses on the jet characteristics and interaction with neighboring jets. The equation governing the transfer of water substances and of electrical charge is given together with a brief description of several semi-empirical, mathematical expressions necessary for the governing equations. The necessary ingredients of a field experiment to verify the system once a prototype is built are described.

Development and construction of a comprehensive set of research diagnostics for the FLARE user facility

NASA Astrophysics Data System (ADS)

Yoo, Jongsoo; Jara-Almonte, J.; Majeski, S.; Frank, S.; Ji, H.; Yamada, M.

2016-10-01

FLARE (Facility for Laboratory Reconnection Experiments) will be operated as a flexible user facility, and so a complete set of research diagnostics is under development, including magnetic probe arrays, Langmuir probes, Mach probes, spectroscopic probes, and a laser interferometer. In order to accommodate the various requirements of users, large-scale (1 m), variable resolution (0.5-4 cm) magnetic probes have been designed, and are currently being prototyped. Moreover, a fully fiber-coupled laser interferometer has been designed to measure the line-integrated electron density. This fiber-coupled interferometer system will reduce the complexity of alignment processes and minimize maintenance of the system. Finally, improvements to the electrostatic probes and spectroscopic probes currently used in the Magnetic Reconnection Experiment (MRX) are discussed. The specifications of other subsystems, such as integrators and digitizers, are also presented. This work is supported by DoE Contract No. DE-AC0209CH11466.

Experimental system, and its evaluation for the control of surgically inducted infections

NASA Technical Reports Server (NTRS)

Tevebaugh, M. D.; Nelson, J. P.

1972-01-01

The effect is reported to design, fabricate, test and evaluate a prototype experimental system for the control of surgically induced infections. The purpose is to provide the cleanest possible environment within a hospital surgery room and eliminate contamination sources that could cause infections during surgery. The system design is described. The system provides for a portable laminar flow clean room, a full bubble helmet system with associated communications and ventilation subsystems for operating room personnel, and surgical gowns that minimize the migration of bacteria. The development test results consisting of portability, laminar flowrate, air flow pattern, electrostatic buildup, noise level, ventilation, human factors, electrical and material compatibility tests are summarized. The conclusions are that the experimental system is effective in reducing the airborne and wound contamination although the helmets and gowns may not be a significant part of this reduction. Definitive conclusions with regard to the infection rate cannot be made at this time.

Long-Range Interactions Restrict Water Transport in Pyrophyllite Interlayers

PubMed Central

Zarzycki, Piotr; Gilbert, Benjamin

2016-01-01

Water diffusion within smectite clay interlayers is reduced by confinement and hence is highly determined by the interlayer spacings that are adopted during swelling. However, a molecular understanding of the short- and long-range forces governing interlayer water structure and dynamics is lacking. Using molecular dynamics simulations of water intercalated between pyrophyllite (smectite prototype) layers we provide a detailed picture of the variation of interlayered water mobility accompanying smectite expansion. Subtle changes in hydrogen bond network structure cause significant changes in water mobility that is greater for stable hydration states and reduced for intermediate separations. By studying pyrophyllite with and without external water we reveal that long-range electrostatic forces apply a restraining effect upon interlayer water mobility. Our findings are relevant for broad range of confining nanostructures with walls thin enough to permit long-range interactions that could affect the mobility of confined solvent molecules and solute species. PMID:27118164

Thermodynamics and kinetics of graphene chemistry: a graphene hydrogenation prototype study.

PubMed

Pham, Buu Q; Gordon, Mark S

2016-12-07

The thermodynamic and kinetic controls of graphene chemistry are studied computationally using a graphene hydrogenation reaction and polyaromatic hydrocarbons to represent the graphene surface. Hydrogen atoms are concertedly chemisorped onto the surface of graphene models of different shapes (i.e., all-zigzag, all-armchair, zigzag-armchair mixed edges) and sizes (i.e., from 16-42 carbon atoms). The second-order Z-averaged perturbation theory (ZAPT2) method combined with Pople double and triple zeta basis sets are used for all calculations. It is found that both the net enthalpy change and the barrier height of graphene hydrogenation at graphene edges are lower than at their interior surfaces. While the thermodynamic product distribution is mainly determined by the remaining π-islands of functionalized graphenes (Phys. Chem. Chem. Phys., 2013, 15, 3725-3735), the kinetics of the reaction is primarily correlated with the localization of the electrostatic potential of the graphene surface.

High-acceleration cable deployment

NASA Technical Reports Server (NTRS)

Barns, C. E.; Canning, T. N.; Gin, B.; King, R. W.; Murphy, J. P.

1980-01-01

Prototype high-acceleration umbilical-cable deployment allows electrical communication between above-ground instrumentation and ballistic projectile below surface. Cable deployment is made up of forebody and afterbody. Foreboy can be separated from afterbody by rocket, or they can be fired as unit at target that stops afterbody on impact (forebody would continue, deploying cable). Similar design could be used in study of sea ice and in other surface-penetration studies.

Ground Rules in Team Projects: Findings from a Prototype System to Support Students

ERIC Educational Resources Information Center

Whatley, Janice

2009-01-01

Student team project work in higher education is one of the best ways to develop team working skills at the same time as learning about the subject matter. As today's students require the freedom to learn at times and places that better match their lifestyles, there is a need for any support for team project work to be also available online. Team…

Portable-Beacon Landing System for Helicopters

NASA Technical Reports Server (NTRS)

Davis, Thomas J.; Clary, George R.; Chisholm, John P.; Macdonald, Stanley L.

1987-01-01

Prototype beacon landing system (BLS) allows helicopters to make precise landings in all weather. BLS easily added to existing helicopter avionic equipment and readily deployed at remote sites. Small and light, system employs X-band radar and digital processing. Variety of beams pulsed sequentially by ground station after initial interrogation by weather radar of approaching helicopter. Airborne microprocessor processes pulses to determine glide slope, course deviation, and range.

Control and Non-Payload Communications (CNPC) Prototype Radio Verification Test Report

NASA Technical Reports Server (NTRS)

Bishop, William D.; Frantz, Brian D.; Thadhani, Suresh K.; Young, Daniel P.

2017-01-01

This report provides an overview and results from the verification of the specifications that defines the operational capabilities of the airborne and ground, L Band and C Band, Command and Non-Payload Communications radio link system. An overview of system verification is provided along with an overview of the operation of the radio. Measurement results are presented for verification of the radios operation.

OGO-1 and OGO-3 MIT plasma experiments S4903

NASA Technical Reports Server (NTRS)

1968-01-01

Plasma proton and plasma electron prototype and flight models were designed, fabricated, and tested. Ground support equipment for the models was also prepared. The flight models were launched aboard the first and third Orbiting Geophysical Observatories on 4 Sept. 1964 and 6 June 1966. These experiments have generally functioned in accordance with the design specifications and useful data are still being received.

Perl Tools for Automating Satellite Ground Systems

NASA Technical Reports Server (NTRS)

McLean, David; Haar, Therese; McDonald, James

2000-01-01

The freeware scripting language Pert offers many opportunities for automating satellite ground systems for new satellites as well as older, in situ systems. This paper describes a toolkit that has evolved from of the experiences gained by using Pert to automate the ground system for the Compton Gamma Ray Observatory (CGRO) and for automating some of the elements in the Earth Observing System Data and Operations System (EDOS) ground system at Goddard Space Flight Center (GSFC). CGRO is an older ground system that was forced to automate because of fund cuts. Three 8 hour shifts were cut back to one 8 hour shift, 7 days per week. EDOS supports a new mission called Terra, launched December 1999 that requires distribution and tracking of mission-critical reports throughout the world. Both of these ground systems use Pert scripts to process data and display it on the Internet as well as scripts to coordinate many of the other systems that make these ground systems work as a coherent whole. Another task called Automated Multimodal Trend Analysis System (AMTAS) is looking at technology for isolation and recovery of spacecraft problems. This effort has led to prototypes that seek to evaluate various tools and technology that meet at least some of the AMTAS goals. The tools, experiences, and lessons learned by implementing these systems are described here.

Footwear and flooring: charge generation in combination with a person as influenced by environmental moisture

NASA Astrophysics Data System (ADS)

Swenson, D. E.

2015-10-01

It is well known that a person walking on a floor will liberate electrostatic charge. The amount of charge that can be accumulated on a person by walking is dependent on many factors that are also well understood. Among these factors is the electrical resistance between a person and ground. The electrical resistance of footwear, other clothing, a person's skin resistance and the contact resistance between footwear and the floor impact the total resistance of the system. As important as measuring resistance may be as an evaluation method, it does not take into account triboelectric generation of charge. The recent revisions of ANSI/ESD S20.20[1] from the ESD Association and IEC61340-5-1[2] from IEC TC101 - Electrostatics, both include a dynamic walking test since experience in recent years has shown that resistance alone does not predict how a footwear and flooring system will actually perform. The USA group ASHRAE1, commissioned a study to evaluate electrostatic charge generation inside data centres as influenced by environmental moisture (relative and absolute humidity)[3][4]. The reason for this study is that past data centre operating guidelines have called for a very narrow range of temperature and humidity control, largely because of the anecdotal evidence that moderate to high RH impacts static electricity generation and accumulation. This results in a massive consumption of electricity to maintain a narrow window of temperature and environmental moisture. Broadening or eliminating humidity controls could result in a major saving of electricity and money.

Stabilization of electrically conducting capillary bridges using feedback control of radial electrostatic stresses and the shapes of extended bridges

NASA Astrophysics Data System (ADS)

Marr-Lyon, Mark J.; Thiessen, David B.; Blonigen, Florian J.; Marston, Philip L.

2000-05-01

Electrically conducting, cylindrical liquid bridges in a density-matched, electrically insulating bath were stabilized beyond the Rayleigh-Plateau (RP) limit using electrostatic stresses applied by concentric ring electrodes. A circular liquid cylinder of length L and radius R in real or simulated zero gravity becomes unstable when the slenderness S=L/2R exceeds π. The initial instability involves the growth of the so-called (2, 0) mode of the bridge in which one side becomes thin and the other side rotund. A mode-sensing optical system detects the growth of the (2, 0) mode and an analog feedback system applies the appropriate voltages to a pair of concentric ring electrodes positioned near the ends of the bridge in order to counter the growth of the (2, 0) mode and prevent breakup of the bridge. The conducting bridge is formed between metal disks which are grounded. Three feedback algorithms were tested and each found capable of stabilizing a bridge well beyond the RP limit. All three algorithms stabilized bridges having S as great as 4.3 and the extended bridges broke immediately when feedback was terminated. One algorithm was suitable for stabilization approaching S=4.493… where the (3, 0) mode is predicted to become unstable for cylindrical bridges. For that algorithm the equilibrium shapes of bridges that were slightly under or over inflated corresponded to solutions of the Young-Laplace equation with negligible electrostatic stresses. The electrical conductivity of the bridge liquid need not be large. The conductivity was associated with salt added to the aqueous bridge liquid.

Air-breathing aerospace plane development essential: Hypersonic propulsion flight tests

NASA Technical Reports Server (NTRS)

Mehta, Unmeel B.

1994-01-01

Hypersonic air-breathing propulsion utilizing scramjets can fundamentally change transatmospheric accelerators for low earth-to-orbit and return transportation. The value and limitations of ground tests, of flight tests, and of computations are presented, and scramjet development requirements are discussed. It is proposed that near full-scale hypersonic propulsion flight tests are essential for developing a prototype hypersonic propulsion system and for developing computational-design technology so that it can be used for designing this system. In order to determine how these objectives should be achieved, some lessons learned from past programs are presented. A conceptual two-stage-to-orbit (TSTO) prototype/experimental aerospace plane is recommended as a means of providing access-to-space and for conducting flight tests. A road map for achieving these objectives is also presented.

High-Temperature Controlled Redox Crystallization Studies

NASA Technical Reports Server (NTRS)

Williams, R. J.

1985-01-01

The crystallization of silicates containing redox sensitive ions (e.g., Fe, Ti, Ce) must be performed under controlled and known redox conditions in order to obtain the maximum scientific benefit from experimental study. Furthermore, many compositions crystallize dense phases which settle during ground-based experiments. This settling influences the texture and chemical evolution of the crystallizing system. The purpose of this investigation is to develop a test system in which controlled redox experiments can be performed in the microgravity environment. The system will use solid ceramic oxygen electrolyte cells for control, measurements, and production of the required redox conditions. A preliminary design for a prototype is developed, the electrolyte and furnace tested, and a tentative protocol for experiment developed. The control parameter is to be established and a laboratory prototype built.

Can space station software be specified through Ada?

NASA Technical Reports Server (NTRS)

Knoebel, Arthur

1987-01-01

Programming of the space station is to be done in the Ada programming language. A breadboard of selected parts of the work package for Marshall Space Flight Center is to be built, and programming this small part will be a good testing ground for Ada. One coding of the upper levels of the design brings out several problems with top-down design when it is to be carried out strictly within the language. Ada is evaluated on the basis of this experience, and the points raised are compared with other experience as related in the literature. Rapid prototyping is another approach to the initial programming; several different types of prototypes are discussed, and compared with the art of specification. Some solutions are proposed and a number of recommendations presented.

Utilizing the EUVE Innovative Technology Testbed to Reduce Operations Cost for Present and Future Orbiting Mission

NASA Technical Reports Server (NTRS)

1997-01-01

This report summarizes work done under Cooperative Agreement (CA) on the following testbed projects: TERRIERS - The development of the ground systems to support the TERRIERS satellite mission at Boston University (BU). HSTS - The application of ARC's Heuristic Scheduling Testbed System (HSTS) to the EUVE satellite mission. SELMON - The application of NASA's Jet Propulsion Laboratory's (JPL) Selective Monitoring (SELMON) system to the EUVE satellite mission. EVE - The development of the EUVE Virtual Environment (EVE), a prototype three-dimensional (3-D) visualization environment for the EUVE satellite and its sensors, instruments, and communications antennae. FIDO - The development of the Fault-Induced Document Officer (FIDO) system, a prototype application to respond to anomalous conditions by automatically searching for, retrieving, and displaying relevant documentation for an operators use.

AeroMACS system characterization and demonstrations

NASA Astrophysics Data System (ADS)

Kerczewski, R. J.; Apaza, R. D.; Dimond, R. P.

This The Aeronautical Mobile Airport Communications System (AeroMACS) is being developed to provide a new broadband wireless communications capability for safety critical communications in the airport surface domain, providing connectivity to aircraft and other ground vehicles as well as connections between other critical airport fixed assets. AeroMACS development has progressed from requirements definition through technology definition, prototype deployment and testing, and now into national and international standards development. The first prototype AeroMACS system has been deployed at the Cleveland Hopkins International Airport (CLE) and the adjacent NASA Glenn Research Center (GRC). During the past three years, extensive technical testing has taken place to characterize the performance of the AeroMACS prototype and provide technical support for the standards development process. The testing has characterized AeroMACS link and network performance over a variety of conditions for both fixed and mobile data transmission and has included basic system performance testing and fixed and mobile applications testing. This paper provides a summary of the AeroMACS performance testing and the status of standardization activities that the testing supports.

AeroMACS System Characterization and Demonstrations

NASA Technical Reports Server (NTRS)

Kerczewski, Robert J.; Apaza, Rafael D.; Dimond, Robert P.

2013-01-01

This The Aeronautical Mobile Airport Communications System (AeroMACS) is being developed to provide a new broadband wireless communications capability for safety critical communications in the airport surface domain, providing connectivity to aircraft and other ground vehicles as well as connections between other critical airport fixed assets. AeroMACS development has progressed from requirements definition through technology definition, prototype deployment and testing, and now into national and international standards development. The first prototype AeroMACS system has been deployed at the Cleveland Hopkins International Airport (CLE) and the adjacent NASA Glenn Research Center (GRC). During the past 3 years, extensive technical testing has taken place to characterize the performance of the AeroMACS prototype and provide technical support for the standards development process. The testing has characterized AeroMACS link and network performance over a variety of conditions for both fixed and mobile data transmission and has included basic system performance testing and fixed and mobile applications testing. This paper provides a summary of the AeroMACS performance testing and the status of standardization activities that the testing supports.

AeroMACS System Characterization and Demonstrations

NASA Technical Reports Server (NTRS)

Kerczewski, Robert J.; Apaza, Rafael D.; Dimond, Robert P.

2013-01-01

The Aeronautical Mobile Airport Communications System (AeroMACS) is being developed to provide a new broadband wireless communications capability for safety critical communications in the airport surface domain, providing connectivity to aircraft and other ground vehicles as well as connections between other critical airport fixed assets. AeroMACS development has progressed from requirements definition through technology definition, prototype deployment and testing, and now into national and international standards development. The first prototype AeroMACS system has been deployed at the Cleveland Hopkins International Airport (CLE) and the adjacent NASA Glenn Research Center (GRC). During the past three years, extensive technical testing has taken place to characterize the performance of the AeroMACS prototype and provide technical support for the standards development process. The testing has characterized AeroMACS link and network performance over a variety of conditions for both fixed and mobile data transmission and has included basic system performance testing and fixed and mobile applications testing. This paper provides a summary of the AeroMACS performance testing and the status of standardization activities that the testing supports.

Advantages of using subsurface flow constructed wetlands for wastewater treatment in space applications: ground-based Mars Base prototype.

PubMed

Nelson, M; Alling, A; Dempster, W F; van Thillo, M; Allen, John

2003-01-01

Research and design of subsurface flow wetland wastewater treatment systems for a ground-based experimental prototype Mars Base facility has been carried out, using a subsurface flow approach. These systems have distinct advantages in planetary exploration scenarios: they are odorless, relatively low-labor and low-energy, assist in purification of water and recycling of atmospheric CO2, and will support some food crops. An area of 6-8 m2 may be sufficient for integration of wetland wastewater treatment with a prototype Mars Base supporting 4-5 people. Discharge water from the wetland system will be used as irrigation water for the agricultural crop area, thus ensuring complete recycling and utilization of nutrients. Since the primary requirements for wetland treatment systems are warm temperatures and lighting, such bioregenerative systems may be integrated into early Mars base habitats, since waste heat from the lights may be used for temperature maintenance in the human living environment. "Wastewater gardens (TM)" can be modified for space habitats to lower space and mass requirements. Many of its construction requirements can eventually be met with use of in-situ materials, such as gravel from the Mars surface. Because the technology requires little machinery and no chemicals, and relies more on natural ecological mechanisms (microbial and plant metabolism), maintenance requirements are minimized, and systems can be expected to have long operating lifetimes. Research needs include suitability of Martian soil and gravel for wetland systems, system sealing and liner options in a Mars Base, and wetland water quality efficiency under varying temperature and light regimes. c2003 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

Water-management models in Florida from ERTS-1 data. [Everglades National Park

NASA Technical Reports Server (NTRS)

Higer, A. L.; Coker, A. E.; Cordes, E. H.

1974-01-01

A prototype multiparameter data acquisition network, installed and operated by the U.S. Geological Survey is a viable approach for obtaining near real-time data needed to solve hydrologic problems confronting nearly 2.5 million residents of south Florida. Selected water quantity and quality data obtained from ground stations are transmitted for relay via ERTS-1 to NASA receiving stations in virtual real time. This data relay system has been very reliable and, by coupling the ground information with ERTS imagery, a modeling technique is available for water resource management in south Florida. An ecological model has been designed for the Shark River Slough in Everglades National Park.

Autonomous Spacecraft Communication Interface for Load Planning

NASA Technical Reports Server (NTRS)

Dever, Timothy P.; May, Ryan D.; Morris, Paul H.

2014-01-01

Ground-based controllers can remain in continuous communication with spacecraft in low Earth orbit (LEO) with near-instantaneous communication speeds. This permits near real-time control of all of the core spacecraft systems by ground personnel. However, as NASA missions move beyond LEO, light-time communication delay issues, such as time lag and low bandwidth, will prohibit this type of operation. As missions become more distant, autonomous control of manned spacecraft will be required. The focus of this paper is the power subsystem. For present missions, controllers on the ground develop a complete schedule of power usage for all spacecraft components. This paper presents work currently underway at NASA to develop an architecture for an autonomous spacecraft, and focuses on the development of communication between the Mission Manager and the Autonomous Power Controller. These two systems must work together in order to plan future load use and respond to unanticipated plan deviations. Using a nominal spacecraft architecture and prototype versions of these two key components, a number of simulations are run under a variety of operational conditions, enabling development of content and format of the messages necessary to achieve the desired goals. The goals include negotiation of a load schedule that meets the global requirements (contained in the Mission Manager) and local power system requirements (contained in the Autonomous Power Controller), and communication of off-plan disturbances that arise while executing a negotiated plan. The message content is developed in two steps: first, a set of rapid-prototyping "paper" simulations are preformed; then the resultant optimized messages are codified for computer communication for use in automated testing.

Moving belt metal detector

NASA Astrophysics Data System (ADS)

Nelson, Carl V.; Mendat, Deborah P.; Huynh, Toan B.

2006-05-01

The Johns Hopkins University Applied Physics Laboratory (APL) has developed a prototype metal detection survey system that will increase the search speed of conventional technology while maintaining high sensitivity. Higher search speeds will reduce the time to clear roads of landmines and improvised explosive devices (IED) and to locate unexploded ordnance (UXO) at Base Realignment and Closure (BRAC) sites, thus reducing remediation costs. The new survey sensor system is called the moving belt metal detector (MBMD) and operates by both increasing sensor speed over the ground while maintaining adequate sensor dwell time over the target for good signal-to-noise ratio (SNR) and reducing motion-induced sensor noise. The MBMD uses an array of metal detection sensors mounted on a flexible belt similar to a tank track. The belt motion is synchronized with the forward survey speed so individual sensor elements remain stationary relative to the ground. A single pulsed transmitter coil is configured to provide a uniform magnetic field along the length of the receivers in ground contact. Individual time-domain electromagnetic induction (EMI) receivers are designed to sense a single time-gate measurement of the total metal content. Each sensor module consists of a receiver coil, amplifier, digitizing electronics and a low power UHF wireless transmitter. This paper presents the survey system design concepts and metal detection data from various targets at several survey speeds. Although the laboratory prototype is designed to demonstrate metal detection survey speeds up to 10 m/s, higher speeds are achievable with a larger sensor array. In addition, the concept can be adapted to work with other sensor technologies not previously considered for moving platforms.

Development of an Unmanned Aircraft System and Cyberinfrastructure for Environmental Science Research

NASA Astrophysics Data System (ADS)

Brady, J. J.; Tweedie, C. E.; Escapita, I. J.

2009-12-01

There is a fundamental need to improve capacities for monitoring environmental change using remote sensing technologies. Recently, researchers have begun using Unmanned Aerial Vehicles (UAVs) to expand and improve upon remote sensing capabilities. Limitations to most non-military and relatively small-scale Unmanned Aircraft Systems (UASs) include a need to develop more reliable communications between ground and aircraft, tools to optimize flight control, real time data processing, and visually ascertaining the quantity of data collected while in air. Here we present a prototype software system that has enhanced communication between ground and the vehicle, can synthesize near real time data acquired from sensors on board, can log operation data during flights, and can visually demonstrate the amount and quality of data for a sampling area. This software has the capacity to greatly improve the utilization of UAS in the environmental sciences. The software system is being designed for use on a paraglider UAV that has a suite of sensors suitable for characterizing the footprints of eddy covariance towers situated in the Chihuahuan Desert and in the Arctic. Sensors on board relay operational flight data (airspeed, ground speed, latitude, longitude, pitch, yaw, roll, acceleration, and video) as well as a suite of customized sensors. Additional sensors can be added to an on board laptop or a CR1000 data logger thereby allowing data from these sensors to be visualized in the prototype software. This poster will describe the development, use and customization of our UAS and multimedia will be available during AGU to illustrate the system in use. UAV on workbench in the lab UAV in flight

Development and performance characterization of an electric ground vehicle with independently actuated in-wheel motors

NASA Astrophysics Data System (ADS)

Wang, Rongrong; Chen, Yan; Feng, Daiwei; Huang, Xiaoyu; Wang, Junmin

This paper presents the development and experimental characterizations of a prototyping pure electric ground vehicle, which is equipped with four independently actuated in-wheel motors (FIAIWM) and is powered by a 72 V 200 Ah LiFeYPO 4 battery pack. Such an electric ground vehicle (EGV) employs four in-wheel (or hub) motors to independently drive/brake the four wheels and is one of the promising vehicle architectures primarily due to its actuation flexibility, energy efficiency, and performance potentials. Experimental data obtained from the EGV chassis dynamometer tests were employed to generate the in-wheel motor torque response and power efficiency maps in both driving and regenerative braking modes. A torque distribution method is proposed to show the potentials of optimizing the FIAIWM EGV operational energy efficiency by utilizing the actuation flexibility and the characterized in-wheel motor efficiency and torque response.

On Possible Arc Inception on Low Voltage Solar Array

NASA Technical Reports Server (NTRS)

Vayner, Boris

2015-01-01

Recent analysis of spacecraft failures during the period of 1990-2013 demonstrated clearly that electrostatic discharges caused more than 8 of all registered failures and anomalies, and comprised the most costly losses (25) for operating companies and agencies. The electrostatic discharges on spacecraft surfaces are the results of differential charging above some critical (threshold) voltages. The mechanisms of differential charging are well known, and various methods have been developed to prevent a generation of significant electric fields in areas of triple junctions. For example, low bus voltages in Low Earth Orbit plasma environment and slightly conducting layer over coverglass (ITO) in Geosynchronous Orbit surroundings are believed to be quite reliable measures to prevent discharges on respective surfaces. In most cases, the vulnerable elements of spacecraft (solar arrays, diode boards, etc.) go through comprehensive ground tests in vacuum chambers. However, tests articles contain the miniscule fragments of spacecraft components such as 10-30 solar cells of many thousands deployed on spacecraft in orbit. This is one reason why manufacturing defects may not be revealed in ground tests but expose themselves in arcing on array surface in space. The other reason for ineffectiveness of discharge preventive measures is aging of all materials in harsh orbital environments. The expected life time of modern spacecraft varies within the range of five-fifteen years, and thermal cycling, radiation damages, and mechanical stresses can result in surface erosion on conductive layers and microscopic cracks in coverglass sheets and adhesive films. These possible damages may cause significant increases in local electric field strengths and subsequent discharges. The primary discharges may or may not be detrimental to spacecraft operation, but they can produce the necessary conditions for sustained arcs initiation. Multiple measures were developed to prevent sustained discharges between adjacent strings, and many ground tests were performed to determine threshold parameters (voltage and current) for sustained arcs. And again, manufacturing defects and aging in space environments may result in considerable decrease of critical threshold parameters. This paper is devoted to the analysis of possible reasons behind arcing on spacecraft with low bus voltages.

On Possible Arc Inception on Low Voltage Solar Array

NASA Technical Reports Server (NTRS)

Vayner, Boris

2015-01-01

Recent analysis of spacecraft failures during the period of 1990-2013 demonstrated clearly that electrostatic discharges caused more than 8 percent of all registered failures and anomalies, and comprised the most costly losses (25 percent) for operating companies and agencies. The electrostatic discharges on spacecraft surfaces are the results of differential charging above some critical (threshold) voltages. The mechanisms of differential charging are well known, and various methods have been developed to prevent a generation of significant electric fields in areas of triple junctions. For example, low bus voltages in Low Earth Orbit plasma environment and slightly conducting layer over cover-glass (ITO) in Geosynchronous Orbit surroundings are believed to be quite reliable measures to prevent discharges on respective surfaces. In most cases, the vulnerable elements of spacecraft (solar arrays, diode boards, etc.) go through comprehensive ground tests in vacuum chambers. However, tests articles contain the miniscule fragments of spacecraft components such as 10-30 solar cells of many thousands deployed on spacecraft in orbit. This is one reason why manufacturing defects may not be revealed in ground tests but expose themselves in arcing on array surface in space. The other reason for ineffectiveness of discharge preventive measures is aging of all materials in harsh orbital environments. The expected life time of modern spacecraft varies within the range of five-fifteen years, and thermal cycling, radiation damages, and mechanical stresses can result in surface erosion on conductive layers and microscopic cracks in cover-glass sheets and adhesive films. These possible damages may cause significant increases in local electric field strengths and subsequent discharges. The primary discharges may or may not be detrimental to spacecraft operation, but they can produce the necessary conditions for sustained arcs initiation. Multiple measures were developed to prevent sustained discharges between adjacent strings, and many ground tests were performed to determine threshold parameters (voltage and current) for sustained arcs. And again, manufacturing defects and aging in space environments may result in considerable decrease of critical threshold parameters. This paper is devoted to the analysis of possible reasons behind arcing on spacecraft with low bus voltages.

Electrostatic transition state stabilization rather than reactant destabilization provides the chemical basis for efficient chorismate mutase catalysis.

PubMed

Burschowsky, Daniel; van Eerde, André; Ökvist, Mats; Kienhöfer, Alexander; Kast, Peter; Hilvert, Donald; Krengel, Ute

2014-12-09

For more than half a century, transition state theory has provided a useful framework for understanding the origins of enzyme catalysis. As proposed by Pauling, enzymes accelerate chemical reactions by binding transition states tighter than substrates, thereby lowering the activation energy compared with that of the corresponding uncatalyzed process. This paradigm has been challenged for chorismate mutase (CM), a well-characterized metabolic enzyme that catalyzes the rearrangement of chorismate to prephenate. Calculations have predicted the decisive factor in CM catalysis to be ground state destabilization rather than transition state stabilization. Using X-ray crystallography, we show, in contrast, that a sluggish variant of Bacillus subtilis CM, in which a cationic active-site arginine was replaced by a neutral citrulline, is a poor catalyst even though it effectively preorganizes chorismate for the reaction. A series of high-resolution molecular snapshots of the reaction coordinate, including the apo enzyme, and complexes with substrate, transition state analog and product, demonstrate that an active site, which is only complementary in shape to a reactive substrate conformer, is insufficient for effective catalysis. Instead, as with other enzymes, electrostatic stabilization of the CM transition state appears to be crucial for achieving high reaction rates.

The effects of patch-potentials on the gravity probe B gyroscopes.

PubMed

Buchman, S; Turneaure, J P

2011-07-01

Gravity probe B (GP-B) was designed to measure the geodetic and frame dragging precessions of gyroscopes in the near field of the Earth using a drag-free satellite in a 642 km polar orbit. Four electrostatically suspended cryogenic gyroscopes were designed to measure the precession of the local inertial frame of reference with a disturbance drift of about 0.1 marc sec/yr-0.2 marc sec/yr. A number of unexpected gyro disturbance effects were observed during the mission: spin-speed and polhode damping, misalignment and roll-polhode resonance torques, forces acting on the gyroscopes, and anomalies in the measurement of the gyro potentials. We show that all these effects except possibly polhode damping can be accounted for by electrostatic patch potentials on both the gyro rotors and the gyro housing suspension and ground-plane electrodes. We express the rotor and housing patch potentials as expansions in spherical harmonics Y(l,m)(θ,φ). Our analysis demonstrates that these disturbance effects are approximated by a power spectrum for the coefficients of the spherical harmonics of the form V(0)(2)/l(r) with V(0) ≈ 100 mV and r ≈ 1.7.

DFT computational analysis of piracetam.

PubMed

Rajesh, P; Gunasekaran, S; Seshadri, S; Gnanasambandan, T

2014-11-11

Density functional theory calculation with B3LYP using 6-31G(d,p) and 6-31++G(d,p) basis set have been used to determine ground state molecular geometries. The first order hyperpolarizability (β0) and related properties (β, α0 and Δα) of piracetam is calculated using B3LYP/6-31G(d,p) method on the finite-field approach. The stability of molecule has been analyzed by using NBO/NLMO analysis. The calculation of first hyperpolarizability shows that the molecule is an attractive molecule for future applications in non-linear optics. Molecular electrostatic potential (MEP) at a point in the space around a molecule gives an indication of the net electrostatic effect produced at that point by the total charge distribution of the molecule. The calculated HOMO and LUMO energies show that charge transfer occurs within these molecules. Mulliken population analysis on atomic charge is also calculated. Because of vibrational analysis, the thermodynamic properties of the title compound at different temperatures have been calculated. Finally, the UV-Vis spectra and electronic absorption properties are explained and illustrated from the frontier molecular orbitals. Copyright © 2014 Elsevier B.V. All rights reserved.

Rationalization of the solvation effects on the AtO+ ground-state change.

PubMed

Ayed, Tahra; Réal, Florent; Montavon, Gilles; Galland, Nicolas

2013-09-12

(211)At radionuclide is of considerable interest as a radiotherapeutic agent for targeted alpha therapy in nuclear medicine, but major obstacles remain because the basic chemistry of astatine (At) is not well understood. The AtO(+) cationic form might be currently used for (211)At-labeling protocols in aqueous solution and has proved to readily react with inorganic/organic ligands. But AtO(+) reactivity must be hindered at first glance by spin restriction quantum rules: the ground state of the free cation has a dominant triplet character. Investigating AtO(+) clustered with an increasing number of water molecules and using various flavors of relativistic quantum methods, we found that AtO(+) adopts in solution a Kramers restricted closed-shell configuration resembling a scalar-relativistic singlet. The ground-state change was traced back to strong interactions, namely, attractive electrostatic interactions and charge transfer, with water molecules of the first solvation shell that lift up the degeneracy of the frontier π* molecular orbitals (MOs). This peculiarity brings an alternative explanation to the highly variable reproducibility reported for some astatine reactions: depending on the production protocols (with distillation in gas-phase or "wet chemistry" extraction), (211)At may or may not readily react.

Cold Rydberg molecules

NASA Astrophysics Data System (ADS)

Raithel, Georg

2017-04-01

Cold atomic systems have opened new frontiers in atomic and molecular physics, including several types of Rydberg molecules. Three types will be reviewed. Long-range Rydberg-ground molecules, first predicted in and observed in, are formed via low-energy electron scattering of the Rydberg electron from a ground-state atom within the Rydberg atom's volume. The binding mostly arises from S- and P-wave triplet scattering. We use a Fermi model that includes S-wave and P-wave singlet and triplet scattering, the fine structure coupling of the Rydberg atom and the hyperfine structure coupling of the 5S1/2 atom (in rubidium). The hyperfine structure gives rise to mixed singlet-triplet potentials for both low-L and high-L Rydberg molecules. A classification into Hund's cases will be discussed. The talk further includes results on adiabatic potentials and adiabatic states of Rydberg-Rydberg molecules in Rb and Cs. These molecules, which have even larger bonding length than Rydberg-ground molecules, are formed via electrostatic multipole interactions. The leading interaction of neutral Rydberg-Rydberg molecules is dipole-dipole, while for ionic Rydberg molecules it is dipole-monopole. Higher-order terms are discussed. FUNDING: NSF (PHY-1506093), NNSF of China (61475123).

Counter Tunnel Exploration, Mapping, and Localization with an Unmanned Ground Vehicle

DTIC Science & Technology

2014-05-01

support terrorist activity. Past robotic tunnel exploration efforts have had limited success in aiding law enforcement to explore and map the suspect...cross-border tunnels. These efforts have made use of adapted explosive ordnance disposal (EOD) or pipe inspection robotic systems that are not ideally... Robotics Enterprise (JGRE) to develop a prototype robotic system for counter-tunnel operations, focusing on exploration, mapping, and characterization of

Integrated Seawater Sampler and Data Acquisition System Prototype

DTIC Science & Technology

1993-04-01

circuitry. The sample bags, initially sealed in a chemically clean environment , were opened by pumping the water out of the tray, thus forcing water into...the water sample containers from materials having low metals content. Control of the sample transfer environment through the use of Class-100 clean... environment . CTD designers also intended their underwater units and deck terminals to be connected directly together providing AC grounding appropriate to

National Radar Conference, Los Angeles, CA, March 12, 13, 1986, Proceedings

NASA Astrophysics Data System (ADS)

The topics discussed include radar systems, radar subsystems, and radar signal processing. Papers are presented on millimeter wave radar for proximity fuzing of smart munitions, a solid state low pulse power ground surveillance radar, and the Radarsat prototype synthetic-aperture radar signal processor. Consideration is also given to automatic track quality assessment in ADT radar systems instrumentation of RCS measurements of modulation spectra of aircraft blades.

UGV History 101: A Brief History of Unmanned Ground Vehicle (UGV) Development Efforts

DTIC Science & Technology

1995-01-01

robots). These successful demonstrations led to the formulation of the Teleoperated Mobile Anti-Armor Platform ( TMAP ) program, and prototype systems were...Unfortunately, Congressional direction in December 1987 prohibited the emplacement of weapons systems on robots, and the TMAP was retargeted to the...Technology Demonstration project, a demonstration incorporating both the Army’s TMAPs and the GATERS TOV was held at Camp Pendleton in September 1989

A 3D Human-Machine Integrated Design and Analysis Framework for Squat Exercises with a Smith Machine.

PubMed

Lee, Haerin; Jung, Moonki; Lee, Ki-Kwang; Lee, Sang Hun

2017-02-06

In this paper, we propose a three-dimensional design and evaluation framework and process based on a probabilistic-based motion synthesis algorithm and biomechanical analysis system for the design of the Smith machine and squat training programs. Moreover, we implemented a prototype system to validate the proposed framework. The framework consists of an integrated human-machine-environment model as well as a squat motion synthesis system and biomechanical analysis system. In the design and evaluation process, we created an integrated model in which interactions between a human body and machine or the ground are modeled as joints with constraints at contact points. Next, we generated Smith squat motion using the motion synthesis program based on a Gaussian process regression algorithm with a set of given values for independent variables. Then, using the biomechanical analysis system, we simulated joint moments and muscle activities from the input of the integrated model and squat motion. We validated the model and algorithm through physical experiments measuring the electromyography (EMG) signals, ground forces, and squat motions as well as through a biomechanical simulation of muscle forces. The proposed approach enables the incorporation of biomechanics in the design process and reduces the need for physical experiments and prototypes in the development of training programs and new Smith machines.

Wrapped Multilayer Insulation

NASA Technical Reports Server (NTRS)

Dye, Scott A.

2015-01-01

New NASA vehicles, such as Earth Departure Stage (EDS), Orion, landers, and orbiting fuel depots, need improved cryogenic propellant transfer and storage for long-duration missions. Current cryogen feed line multilayer insulation (MLI) performance is 10 times worse per area than tank MLI insulation. During each launch, cryogenic piping loses approximately 150,000 gallons (equivalent to $300,000) in boil-off during transfer, chill down, and ground hold. Quest Product Development Corp., teaming with Ball Aerospace, developed an innovative advanced insulation system, Wrapped MLI (wMLI), to provide improved thermal insulation for cryogenic feed lines. wMLI is high-performance multilayer insulation designed for cryogenic piping. It uses Quest's innovative discrete-spacer technology to control layer spacing/ density and reduce heat leak. The Phase I project successfully designed, built, and tested a wMLI prototype with a measured heat leak 3.6X lower than spiral-wrapped conventional MLI widely used for piping insulation. A wMLI prototype had a heat leak of 7.3 W/sq m, or 27 percent of the heat leak of conventional MLI (26.7 W/sq m). The Phase II project is further developing wMLI technology with custom, molded polymer spacers and advancing the product toward commercialization via a rigorous testing program, including developing advanced vacuuminsulated pipe for ground support equipment.

Wrapped Multilayer Insulation

NASA Technical Reports Server (NTRS)

Dye, Scott A.

2015-01-01

New NASA vehicles, such as Earth Departure Stage (EDS), Orion, landers, and orbiting fuel depots, need improved cryogenic propellant transfer and storage for long-duration missions. Current cryogen feed line multilayer insulation (MLI) performance is 10 times worse per area than tank MLI insulation. During each launch, cryogenic piping loses approximately 150,000 gallons (equivalent to $300,000) in boil-off during transfer, chill down, and ground hold. Quest Product Development Corp., teaming with Ball Aerospace, developed an innovative advanced insulation system, Wrapped MLI (wMLI), to provide improved thermal insulation for cryogenic feed lines. wMLI is high-performance multilayer insulation designed for cryogenic piping. It uses Quest's innovative discrete-spacer technology to control layer spacing/ density and reduce heat leak. The Phase I project successfully designed, built, and tested a wMLI prototype with a measured heat leak 3.6X lower than spiral-wrapped conventional MLI widely used for piping insulation. A wMLI prototype had a heat leak of 7.3 W/m2, or 27 percent of the heat leak of conventional MLI (26.7 W/m2). The Phase II project is further developing wMLI technology with custom, molded polymer spacers and advancing the product toward commercialization via a rigorous testing program, including developing advanced vacuuminsulated pipe for ground support equipment.

Using Stars to Align a Steered Laser System for Cosmic Ray Simulation

NASA Astrophysics Data System (ADS)

Krantz, Harry; Wiencke, Lawrence

2016-03-01

Ultra high energy cosmic rays (UHECRs) are the highest energy cosmic particles with kinetic energy above 1018eV . UHECRs are detected from the air shower of secondary particles and UV florescence that results from interaction with the atmosphere. A high power UV laser beam can be used to simulate the optical signature of a UHCER air shower. The Global Light System (GLS) is a planned network of ground-based light sources including lasers to support the planned space-based Extreme Universe Space Observatory (EUSO). A portable prototype GLS laser station has been constructed at the Colorado School of Mines. Currently the laser system uses reference targets on the ground but stars can be used to better align the beam by providing a complete hemisphere of targets. In this work, a CCD camera is used to capture images of known stars through the steering head optics. The images are analyzed to find the steering head coordinates of the target star. The true coordinates of the star are calculated from the location and time of observation. A universal adjustment for the steering head is determined from the differences between the two pairs of coordinates across multiple stars. This laser system prototype will also be used for preflight tests of the ESUO Super Pressure Balloon mission.

Miniaturized dual band multislotted patch antenna on polytetrafluoroethylene glass microfiber reinforced for C/X band applications.

PubMed

Islam, M T; Samsuzzaman, M

2014-01-01

This paper introduces a new configuration of compact, triangular- and diamond-slotted, microstrip-fed, low-profile antenna for C/X band applications on polytetrafluoroethylene glass microfiber reinforced material substrate. The antenna is composed of a rectangular-shaped patch containing eight triangles and two diamond-shaped slots and an elliptical-slotted ground plane. The rectangular-shaped patch is obtained by cutting two diamond slots in the middle of the rectangular patch, six triangular slots on the left and right side of the patch, and two triangular slots on the up and down side of the patch. The slotted radiating patch, the elliptical-slotted ground plane, and the microstrip feed enable the matching bandwidth to be widened. A prototype of the optimized antenna was fabricated on polytetrafluoroethylene glass microfiber reinforced material substrate using LPKF prototyping machine and investigated to validate the proposed design. The simulated results are compared with the measured data, and good agreement is achieved. The proposed antenna offers fractional bandwidths of 13.69% (7.78-8.91 GHz) and 10.35% (9.16-10.19 GHz) where S11 < -10 dB at center frequencies of 8.25 GHz and 9.95 GHz, respectively, and relatively stable gain, good radiation efficiency, and omnidirectional radiation patterns in the matching band.

A 3D Human-Machine Integrated Design and Analysis Framework for Squat Exercises with a Smith Machine

PubMed Central

Lee, Haerin; Jung, Moonki; Lee, Ki-Kwang; Lee, Sang Hun

2017-01-01

In this paper, we propose a three-dimensional design and evaluation framework and process based on a probabilistic-based motion synthesis algorithm and biomechanical analysis system for the design of the Smith machine and squat training programs. Moreover, we implemented a prototype system to validate the proposed framework. The framework consists of an integrated human–machine–environment model as well as a squat motion synthesis system and biomechanical analysis system. In the design and evaluation process, we created an integrated model in which interactions between a human body and machine or the ground are modeled as joints with constraints at contact points. Next, we generated Smith squat motion using the motion synthesis program based on a Gaussian process regression algorithm with a set of given values for independent variables. Then, using the biomechanical analysis system, we simulated joint moments and muscle activities from the input of the integrated model and squat motion. We validated the model and algorithm through physical experiments measuring the electromyography (EMG) signals, ground forces, and squat motions as well as through a biomechanical simulation of muscle forces. The proposed approach enables the incorporation of biomechanics in the design process and reduces the need for physical experiments and prototypes in the development of training programs and new Smith machines. PMID:28178184

Testing of the Prototype Mars Drill and Sample Acquisition System in the Mars Analog Site of the Antarctica's Dry Valleys

NASA Astrophysics Data System (ADS)

Zacny, K.; Paulsen, G.; McKay, C.; Glass, B. J.; Marinova, M.; Davila, A. F.; Pollard, W. H.; Jackson, A.

2011-12-01

We report on the testing of the one meter class prototype Mars drill and cuttings sampling system, called the IceBreaker in the Dry Valleys of Antarctica. The drill consists of a rotary-percussive drill head, a sampling auger with a bit at the end having an integrated temperature sensor, a Z-stage for advancing the auger into the ground, and a sampling station for moving the augered ice shavings or soil cuttings into a sample cup. In November/December of 2010, the IceBreaker drill was tested in the Uni-versity Valley (within the Beacon Valley region of the Antarctic Dry Valleys). University Valley is a good analog to the Northern Polar Regions of Mars because a layer of dry soil lies on top of either ice-cemeted ground or massive ice (depending on the location within the valley). That is exactly what the 2007 Phoenix mission discovered on Mars. The drill demonstrated drilling in ice-cemented ground and in massive ice at the 1-1-100-100 level; that is the drill reached 1 meter in 1 hour with 100 Watts of power and 100 Newton Weight on Bit. This corresponds to an average energy of 100 Whr. At the same time, the bit temperature measured by the bit thermocouple did not exceed more than 10 °C above the formation temperature. The temperature also never exceeded freezing, which minimizes chances of getting stuck and also of altering the materials that are being sampled and analyzed. The samples in the forms of cuttings were acquired every 10 cm intervals into sterile bags. These tests have shown that drilling on Mars, in ice cemented ground with limited power, energy and Weight on Bit, and collecting samples in discrete depth intervals is possible within the given mass, power, and energy levels of a Phoenix-size lander and within the duration of a Phoenix-like mission.

MOORE: A prototype expert system for diagnosing spacecraft problems

NASA Technical Reports Server (NTRS)

Howlin, Katherine; Weissert, Jerry; Krantz, Kerry

1988-01-01

MOORE is a rule-based, prototype expert system that assists in diagnosing operational Tracking and Data Relay Satellite (TDRS) problems. It is intended to assist spacecraft engineers at the TDRS ground terminal in trouble shooting problems that are not readily solved with routine procedures, and without expert counsel. An additional goal of the prototype system is to develop in-house expert system and knowledge engineering skills. The prototype system diagnoses antenna pointing and earth pointing problems that may occur within the TDRS Attitude Control System (ACS). Plans include expansion to fault isolation of problems in the most critical subsystems of the TDRS spacecraft. Long term benefits are anticipated with use of an expert system during future TDRS programs with increased mission support time, reduced problem solving time, and retained expert knowledge and experience. Phase 2 of the project is intended to provide NASA the necessary expertise and capability to define requirements, evaluate proposals, and monitor the development progress of a highly competent expert system for NASA's Tracking Data Relay Satellite. Phase 2 also envisions addressing two unexplored applications for expert systems, spacecraft integration and tests (I and T) and support to launch activities. The concept, goals, domain, tools, knowledge acquisition, developmental approach, and design of the expert system. It will explain how NASA obtained the knowledge and capability to develop the system in-house without assistance from outside consultants. Future plans will also be presented.

Optical development system lab alignment solutions for the ICESat-2 ATLAS instrument

NASA Astrophysics Data System (ADS)

Evans, T.

The ATLAS Instrument for the ICESat-2 mission at NASA's Goddard Space Flight Center requires an alignment test-bed to prove out new concepts. The Optical Development System (ODS) lab was created to test prototype models of individual instrument components to simulate how they will act as a system. The main ICESat-2 instrument is the Advanced Topographic Laser Altimeter System (ATLAS). It measures ice elevation by transmitting laser pulses, and collecting the reflection in a telescope. Because the round trip time is used to calculate distance, alignment between the outgoing transmitter beam and the incoming receiver beams are critical. An automated closed loop monitoring control system is currently being tested at the prototype level to prove out implementation for the final spacecraft. To achieve an error of less than 2 micro-radians, an active deformable mirror was used to correct the lab wave front from the collimated “ ground reflection” beam. The lab includes a focal plane assembly set up, a one meter diameter collimator optic, and a 0.8 meter flight spare telescope for alignment. ATLAS prototypes and engineering models of transmitter and receiver optics and sub-systems are brought in to develop and integrate systems as well as write procedures to be used in integration and testing. By having a fully integrated system with prototypes and engineering units, lessons can be learned before flight designs are finalized.

An earthworm-like robot using origami-ball structures

NASA Astrophysics Data System (ADS)

Fang, Hongbin; Zhang, Yetong; Wang, K. W.

2017-04-01

Earthworms possess extraordinary on-ground and underground mobility, which inspired researchers to mimic their morphology characteristics and locomotion mechanisms to develop crawling robots. One of the bottlenecks that constrain the development and wide-spread application of earthworm-like robots is the process of design, fabrication and assembly of the robot frameworks. Here we present a new earthworm-like robot design and prototype by exploring and utilizing origami ball structures. The origami ball is able to antagonistically output both axial and radial deformations, similar as an earthworm's body segment. The origami folding techniques also introduce many advantages to the robot development, including precise and low cost fabrication and high customizability. Starting from a flat polymer film, we adopt laser machining technique to engrave the crease pattern and manually fold the patterned flat film into an origami ball. Coupling the ball with a servomotor-driven linkage yields a robot segment. Connecting six segments in series, we obtain an earthworm-like origami robot prototype. The prototype is tested in a tube to evaluate its locomotion performance. It shows that the robot could crawl effectively in the tube, manifesting the feasibility of the origami-based design. In addition, test results indicate that the robot's locomotion could be tailored by employing different peristalsis-wave based gaits. The robot design and prototype reported in this paper could foster a new breed of crawling robots with simply design, fabrication, and assemble processes, and improved locomotion performance.

Density functional theory studies on the electronic, structural, phonon dynamical and thermo-stability properties of bicarbonates MHCO3, M = Li, Na, K

NASA Astrophysics Data System (ADS)

Duan, Yuhua; Zhang, Bo; Sorescu, Dan C.; Johnson, J. Karl; Majzoub, Eric H.; Luebke, David R.

2012-08-01

The structural, electronic, phonon dispersion and thermodynamic properties of MHCO3 (M = Li, Na, K) solids were investigated using density functional theory. The calculated bulk properties for both their ambient and the high-pressure phases are in good agreement with available experimental measurements. Solid phase LiHCO3 has not yet been observed experimentally. We have predicted several possible crystal structures for LiHCO3 using crystallographic database searching and prototype electrostatic ground state modeling. Our total energy and phonon free energy (FPH) calculations predict that LiHCO3 will be stable under suitable conditions of temperature and partial pressures of CO2 and H2O. Our calculations indicate that the {{HCO}}_{3}^{-} groups in LiHCO3 and NaHCO3 form an infinite chain structure through O⋯H⋯O hydrogen bonds. In contrast, the {{HCO}}_{3}^{-} anions form dimers, ({{HCO}}_{3}^{-})_{2}, connected through double hydrogen bonds in all phases of KHCO3. Based on density functional perturbation theory, the Born effective charge tensor of each atom type was obtained for all phases of the bicarbonates. Their phonon dispersions with the longitudinal optical-transverse optical splitting were also investigated. Based on lattice phonon dynamics study, the infrared spectra and the thermodynamic properties of these bicarbonates were obtained. Over the temperature range 0-900 K, the FPH and the entropies (S) of MHCO3 (M =Li, Na, K) systems vary as FPH(LiHCO3) > FPH(NaHCO3) > FPH(KHCO3) and S(KHCO3) > S(NaHCO3) > S(LiHCO3), respectively, in agreement with the available experimental data. Analysis of the predicted thermodynamics of the CO2 capture reactions indicates that the carbonate/bicarbonate transition reactions for Na and K could be used for CO2 capture technology, in agreement with experiments.

Multisource inverse-geometry CT. Part II. X-ray source design and prototype

PubMed Central

Neculaes, V. Bogdan; Caiafa, Antonio; Cao, Yang; De Man, Bruno; Edic, Peter M.; Frutschy, Kristopher; Gunturi, Satish; Inzinna, Lou; Reynolds, Joseph; Vermilyea, Mark; Wagner, David; Zhang, Xi; Zou, Yun; Pelc, Norbert J.; Lounsberry, Brian

2016-01-01

Purpose: This paper summarizes the development of a high-power distributed x-ray source, or “multisource,” designed for inverse-geometry computed tomography (CT) applications [see B. De Man et al., “Multisource inverse-geometry CT. Part I. System concept and development,” Med. Phys. 43, 4607–4616 (2016)]. The paper presents the evolution of the source architecture, component design (anode, emitter, beam optics, control electronics, high voltage insulator), and experimental validation. Methods: Dispenser cathode emitters were chosen as electron sources. A modular design was adopted, with eight electron emitters (two rows of four emitters) per module, wherein tungsten targets were brazed onto copper anode blocks—one anode block per module. A specialized ceramic connector provided high voltage standoff capability and cooling oil flow to the anode. A matrix topology and low-noise electronic controls provided switching of the emitters. Results: Four modules (32 x-ray sources in two rows of 16) have been successfully integrated into a single vacuum vessel and operated on an inverse-geometry computed tomography system. Dispenser cathodes provided high beam current (>1000 mA) in pulse mode, and the electrostatic lenses focused the current beam to a small optical focal spot size (0.5 × 1.4 mm). Controlled emitter grid voltage allowed the beam current to be varied for each source, providing the ability to modulate beam current across the fan of the x-ray beam, denoted as a virtual bowtie filter. The custom designed controls achieved x-ray source switching in <1 μs. The cathode-grounded source was operated successfully up to 120 kV. Conclusions: A high-power, distributed x-ray source for inverse-geometry CT applications was successfully designed, fabricated, and operated. Future embodiments may increase the number of spots and utilize fast read out detectors to increase the x-ray flux magnitude further, while still staying within the stationary target inherent thermal limitations. PMID:27487878

Multisource inverse-geometry CT. Part II. X-ray source design and prototype

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neculaes, V. Bogdan, E-mail: neculaes@ge.com; Caia

2016-08-15

Purpose: This paper summarizes the development of a high-power distributed x-ray source, or “multisource,” designed for inverse-geometry computed tomography (CT) applications [see B. De Man et al., “Multisource inverse-geometry CT. Part I. System concept and development,” Med. Phys. 43, 4607–4616 (2016)]. The paper presents the evolution of the source architecture, component design (anode, emitter, beam optics, control electronics, high voltage insulator), and experimental validation. Methods: Dispenser cathode emitters were chosen as electron sources. A modular design was adopted, with eight electron emitters (two rows of four emitters) per module, wherein tungsten targets were brazed onto copper anode blocks—one anode blockmore » per module. A specialized ceramic connector provided high voltage standoff capability and cooling oil flow to the anode. A matrix topology and low-noise electronic controls provided switching of the emitters. Results: Four modules (32 x-ray sources in two rows of 16) have been successfully integrated into a single vacuum vessel and operated on an inverse-geometry computed tomography system. Dispenser cathodes provided high beam current (>1000 mA) in pulse mode, and the electrostatic lenses focused the current beam to a small optical focal spot size (0.5 × 1.4 mm). Controlled emitter grid voltage allowed the beam current to be varied for each source, providing the ability to modulate beam current across the fan of the x-ray beam, denoted as a virtual bowtie filter. The custom designed controls achieved x-ray source switching in <1 μs. The cathode-grounded source was operated successfully up to 120 kV. Conclusions: A high-power, distributed x-ray source for inverse-geometry CT applications was successfully designed, fabricated, and operated. Future embodiments may increase the number of spots and utilize fast read out detectors to increase the x-ray flux magnitude further, while still staying within the stationary target inherent thermal limitations.« less

The Experiment that Came from the Cold: Results from the Recovered REXUS 12 Suaineadh Spinning Web Experiment

NASA Astrophysics Data System (ADS)

Sinn, T.; McRobb, M.; Wujek, A.; Skogby, J.; Rogberg, F.; Wang, J.; Vasile, M.; Tibert, G.; Mao, H.

2015-09-01

The Suaineadh experiment had the purpose to deploy a 2m x 2m web in milli gravity conditions by using the centrifugal forces acting on corner sections of a web that is spinning around a central hub. Continuous exploration of our solar system and beyond requires ever larger structures in space. But the biggest problem nowadays is the transport of these structures into space due to launch vehicle payload volume constrains. By making the space structures deployable with minimum storage properties, this constrain may be bypassed. Deployable concepts range from inflatables, foldables, electrostatic to spinning web deployment. The advantage of the web deployment is the very low storage volume and the simple deployment mechanism. These webs can act as lightweight platforms for the construction of large structures in space without the huge expense of launching heavy structures from Earth. The Suaineadh experiment was launched onboard the sounding rocket REXUS12 in March 2012. After achieving the required altidue, the Suaineadh experiment was ejected from the rocket in order to be fully free flying. A specially designed spinning wheel in the ejected section was then used to spin up the experiment until the required rate is achieved for web deployment to commence. Unfortunately during re-entry, the probe was lost and also a recovery mission in August 20 1 2 was only able to find minor components of the experiment. After 18 month, in September 201 3 , the experiment was found in the wilderness of Northern Sweden. In the following months all data from the experiment could be recovered. The images and accelerometer~ data that has been analysed showed the deployment of the web and a very interesting three dimensional behaviour that differs greatly from on ground two dimensional prototype tests. This paper will give an overview on the recovered data and it will present the analysed results of the Suaineadh spinning web experiment.

Compact electrostatic comb actuator

DOEpatents

Rodgers, M. Steven; Burg, Michael S.; Jensen, Brian D.; Miller, Samuel L.; Barnes, Stephen M.

2000-01-01

A compact electrostatic comb actuator is disclosed for microelectromechanical (MEM) applications. The actuator is based upon a plurality of meshed electrostatic combs, some of which are stationary and others of which are moveable. One or more restoring springs are fabricated within an outline of the electrostatic combs (i.e. superposed with the moveable electrostatic combs) to considerably reduce the space required for the actuator. Additionally, a truss structure is provided to support the moveable electrostatic combs and prevent bending or distortion of these combs due to unbalanced electrostatic forces or external loading. The truss structure formed about the moveable electrostatic combs allows the spacing between the interdigitated fingers of the combs to be reduced to about one micron or less, thereby substantially increasing the number of active fingers which can be provided in a given area. Finally, electrostatic shields can be used in the actuator to substantially reduce unwanted electrostatic fields to further improve performance of the device. As a result, the compact electrostatic comb actuator of the present invention occupies only a fraction of the space required for conventional electrostatic comb actuators, while providing a substantial increase in the available drive force (up to one-hundred times).

Traveling wave tube and method of manufacture

NASA Technical Reports Server (NTRS)

Vancil, Bernard K. (Inventor)

2004-01-01

A traveling wave tube includes a glass or other insulating envelope having a plurality of substantially parallel glass rods supported therewithin which in turn support an electron gun, a collector and an intermediate slow wave structure. The slow wave structure itself provides electrostatic focussing of a central electron beam thereby eliminating the need for focussing magnetics and materially decreasing the cost of construction as well as enabling miniaturization. The slow wave structure advantageously includes cavities along the electron beam through which the r.f. energy is propagated, or a double, interleaved ring loop structure supported by dielectric fins within a ground plane cylinder disposed coaxially within the glass envelope.

Experimenting with an Evolving Ground/Space-based Software Architecture to Enable Sensor Webs

NASA Technical Reports Server (NTRS)

mandl, Daniel; Frye, Stuart

2005-01-01

A series of ongoing experiments are being conducted at the NASA Goddard Space Flight Center to explore integrated ground and space-based software architectures enabling sensor webs. A sensor web, as defined by Steve Talabac at NASA Goddard Space Flight Center(GSFC), is a coherent set of distributed nodes interconnected by a communications fabric, that collectively behave as a single, dynamically adaptive, observing system. The nodes can be comprised of satellites, ground instruments, computing nodes etc. Sensor web capability requires autonomous management of constellation resources. This becomes progressively more important as more and more satellites share resource, such as communication channels and ground station,s while automatically coordinating their activities. There have been five ongoing activities which include an effort to standardize a set of middleware. This paper will describe one set of activities using the Earth Observing 1 satellite, which used a variety of ground and flight software along with other satellites and ground sensors to prototype a sensor web. This activity allowed us to explore where the difficulties that occur in the assembly of sensor webs given today s technology. We will present an overview of the software system architecture, some key experiments and lessons learned to facilitate better sensor webs in the future.

Innovative Applications of Laser Scanning and Rapid Prototype Printing to Rock Breakdown Experiments

NASA Technical Reports Server (NTRS)

Bourke, Mary; Viles, Heather; Nicoll, Joe; Lyew-Ayee, Parris; Ghent, Rebecca; Holmlund, James

2008-01-01

We present the novel application of two technologies for use in rock breakdown experiments, i.e. close-range, ground-based 3D triangulation scanning and rapid prototype printing. These techniques aid analyses of form-process interactions across the range of scales relevant to breakdown (micron-m). This is achieved through (a) the creation of DEMs (which permit quantitative description and analysis of rock surface morphology and morphological change) and (b) the production of more realistically-shaped experimental blocks. We illustrate the use of these techniques, alongside appropriate data analysis routines, in experiments designed to investigate the persistence of fluvially-derived features in the face of subsequent wind abrasion and weathering. These techniques have a range of potential applications in experimental field and lab-based geomorphic studies beyond those specifically outlined here.

An automated environment for multiple spacecraft engineering subsystem mission operations

NASA Technical Reports Server (NTRS)

Bahrami, K. A.; Hioe, K.; Lai, J.; Imlay, E.; Schwuttke, U.; Hsu, E.; Mikes, S.

1990-01-01

Flight operations at the Jet Propulsion Laboratory (JPL) are now performed by teams of specialists, each team dedicated to a particular spacecraft. Certain members of each team are responsible for monitoring the performances of their respective spacecraft subsystems. Ground operations, which are very complex, are manual, labor-intensive, slow, and tedious, and therefore costly and inefficient. The challenge of the new decade is to operate a large number of spacecraft simultaneously while sharing limited human and computer resources, without compromising overall reliability. The Engineering Analysis Subsystem Environment (EASE) is an architecture that enables fewer controllers to monitor and control spacecraft engineering subsystems. A prototype of EASE has been installed in the JPL Space Flight Operations Facility for on-line testing. This article describes the underlying concept, development, testing, and benefits of the EASE prototype.

Thermal Actuation Based 3-DoF Non-Resonant Microgyroscope Using MetalMUMPs

PubMed Central

Shakoor, Rana Iqtidar; Bazaz, Shafaat Ahmed; Kraft, Michael; Lai, Yongjun; Masood ul Hassan, Muhammad

2009-01-01

High force, large displacement and low voltage consumption are a primary concern for microgyroscopes. The chevron-shaped thermal actuators are unique in terms of high force generation combined with the large displacements at a low operating voltage in comparison with traditional electrostatic actuators. A Nickel based 3-DoF micromachined gyroscope comprising 2-DoF drive mode and 1-DoF sense mode oscillator utilizing the chevron-shaped thermal actuators is presented here. Analytical derivations and finite element simulations are carried out to predict the performance of the proposed device using the thermo-physical properties of electroplated nickel. The device sensitivity is improved by utilizing the dynamical amplification of the oscillation in 2-DoF drive mode using an active-passive mass configuration. A comprehensive theoretical description, dynamics and mechanical design considerations of the proposed gyroscopes model are discussed in detail. Parametric optimization of gyroscope, its prototype modeling and fabrication using MetalMUMPs has also been investigated. Dynamic transient simulation results predicted that the sense mass of the proposed device achieved a drive displacement of 4.1μm when a sinusoidal voltage of 0.5V is applied at 1.77 kHz exhibiting a mechanical sensitivity of 1.7μm /°/s in vacuum. The wide bandwidth frequency response of the 2-DoF drive mode oscillator consists of two resonant peaks and a flat region of 2.11 kHz between the peaks defining the operational frequency region. The sense mode resonant frequency can lie anywhere within this region and therefore the amplitude of the response is insensitive to structural parameter variations, enhancing device robustness against such variations. The proposed device has a size of 2.2 × 2.6 mm2, almost one third in comparison with existing M-DoF vibratory gyroscope with an estimated power consumption of 0.26 Watts. These predicted results illustrate that the chevron-shaped thermal actuator has a large voltage-stroke ratio shifting the paradigm in MEMS gyroscope design from the traditional interdigitated comb drive electrostatic actuator. These actuators have low damping compared to electrostatic comb drive actuators which may result in high quality factor microgyroscopes operating at atmospheric pressure. PMID:22574020

A Low-Voltage and High Uniformity Nano-Electro-Mechanical System Tunable Color Filter Based on Subwavelength Grating

NASA Astrophysics Data System (ADS)

Honma, Hiroaki; Takahashi, Kazuhiro; Ishida, Makoto; Sawada, Kazuaki

2012-11-01

This paper reports on the construction of a nano-electro-mechanical system (NEMS) tunable color filter based on a subwavelength grating with high color uniformity and a low drive voltage. We recently proposed a ground-voltage-ground (GVG)-type tunable color filter with a parallel-plate actuator with three pairs of electrodes to decrease the crosstalk due to the electrostatic attractive force between each pair of actuators. Our finite element method (FEM) simulation results indicate that the drive voltage is decreased by 10 V, as compared to that of the previously reported GV type. The proposed structure was fabricated using a silicon-on-insulator (SOI) wafer. The color tuning capability of the device was demonstrated by applying a drive voltage of 6.7 V. The reflected light intensity was decreased by 34% at a wavelength of 680 nm. Color uniformity was also obtained in the filter area by reducing the variation of the displacement on the one-dimensional actuator arrays.

Quantitative ESD Guidelines for Charged Spacecraft Derived from the Physics of Discharges

NASA Technical Reports Server (NTRS)

Frederickson, A. R.

1992-01-01

Quantitative guidelines are proposed for Electrostatic Discharge (ESD) pulse shape on charged spacecraft. The guidelines are based on existing ground test data, and on a physical description of the pulsed discharge process. The guidelines are designed to predict pulse shape for surface charging and internal charging on a wide variety of spacecraft structures. The pulses depend on the area of the sample, its capacitance to ground, and the strength of the electric field in the vacuum adjacent to the charged surface. By knowing the pulse shape, current vs. time, one can determine if nearby circuits are threatened by the pulse. The quantitative guidelines might be used to estimate the level of threat to an existing spacecraft, or to redesign a spacecraft to reduce its pulses to a known safe level. The experiments which provide the data and the physics that allow one to interpret the data will be discussed, culminating in examples of how to predict pulse shape/size. This method has been used, but not confirmed, on several spacecraft.

Valence tautomerism in synthetic models of cytochrome P450

PubMed Central

Das, Pradip Kumar; Samanta, Subhra; McQuarters, Ashley B.; Lehnert, Nicolai

2016-01-01

CytP450s have a cysteine-bound heme cofactor that, in its as-isolated resting (oxidized) form, can be conclusively described as a ferric thiolate species. Unlike the native enzyme, most synthetic thiolate-bound ferric porphyrins are unstable in air unless the axial thiolate ligand is sterically protected. Spectroscopic investigations on a series of synthetic mimics of cytP450 indicate that a thiolate-bound ferric porphyrin coexists in organic solutions at room temperature (RT) with a thiyl-radical bound ferrous porphyrin, i.e., its valence tautomer. The ferric thiolate state is favored by greater enthalpy and is air stable. The ferrous thiyl state is favored by entropy, populates at RT, and degrades in air. These ground states can be reversibly interchanged at RT by the addition or removal of water to the apolar medium. It is concluded that hydrogen bonding and local electrostatics protect the resting oxidized cytP450 active site from degradation in air by stabilizing the ferric thiolate ground state in contrast to its synthetic analogs. PMID:27302948

Skylab program payload integration. Skylab film environmental effects

NASA Technical Reports Server (NTRS)

1975-01-01

The effects of the Skylab environments on the 22 types of film used for data recording on Skylab were evaluated. Environmental histories and sensitometric curves for 114 rolls of film used for this evaluation are presented. Photographic parameters evaluated in detail were film fogging of black and white films, changes in maximum density of color film, latent image fading, and changes in film sensitivity. Other photographic and film physical anomalies such as electrostatic exposure, emulsion cracking, and reciprocity failure were also documented. Results based upon comparison of film sensitometric data for flight film with ground control film and ground test film are presented independently for each film type. The study showed that photographic film fulfilled the requirements of the Skylab applications in which it was used. Environmental film degradation, although present on almost every roll, did not preclude recording sufficient data to meet experiment requirements for all film, except film type SC-5. Specific conclusions are provided in the areas of further analyses, tests, and developments.

Reduced-Gravity Measurements of the Effect of Oxygen on Properties of Zirconium

NASA Technical Reports Server (NTRS)

Zhao, J.; Lee, J.; Wunderlich, R.; Fecht, H.-J.; Schneider, S.; SanSoucie, M.; Rogers, J.; Hyers, R.

2016-01-01

The influence of oxygen on the thermophysical properties of zirconium is being investigated using MSL-EML (Material Science Laboratory - Electromagnetic Levitator) on ISS (International Space Station) in collaboration with NASA, ESA (European Space Agency), and DLR (German Aerospace Center). Zirconium samples with different oxygen concentrations will be put into multiple melt cycles, during which the density, viscosity, surface tension, heat capacity, and electric conductivity will be measured at various undercooled temperatures. The facility check-up of MSL-EML and the first set of melting experiments have been successfully performed in 2015. The first zirconium sample will be tested near the end of 2015. As part of ground support activities, the thermophysical properties of zirconium and ZrO were measured using a ground-based electrostatic levitator located at the NASA Marshall Space Flight Center. The influence of oxygen on the measured surface tension was evaluated. The results of this research will serve as reference data for those measured in ISS.

Experimental Studies of Quasi-Adiabatic Quantum-dot Cellular Automata

NASA Astrophysics Data System (ADS)

Orlov, Alexei; Amlani, Islamshah; Kummamuru, Ravi; Toth, Geza; Bernstein, Gary; Lent, Craig; Snider, Gregory

2000-03-01

The computational approach known as Quantum-dot Cellular Automata (QCA) uses interacting quantum dots to encode and process binary information. The first realization of a functioning QCA cell has already been reported. Recently, quasi-adiabatic switching of QCA in a metal dot system near the instantaneous ground state was proposed [1]. The advantage if this approach is that it allows both logic and addressable memory to be implemented within the QCA framework. We report on the fabrication and measurement of such a device in the Al-AlOx tunnel junction system. This basic building block consists of three metal islands connected in series by tunnel junctions, where an electron can be moved between islands by means of electrostatic perturbation on either control electrodes or adjacent cells. The cell can have three operational modes, i.e. active, locked and null, which provide a solution for ground state computing that is not susceptible to metastable states. [1] G. Toth and C. S. Lent, J. appl. Phys. 85 5, 2977-2984, 1999.

The Microscope Space Mission and the In-Orbit Calibration Plan for its Instrument

NASA Astrophysics Data System (ADS)

Levy, Agnès Touboul, Pierre; Rodrigues, Manuel; Onera, Émilie Hardy; Métris, Gilles; Robert, Alain

2015-01-01

The MICROSCOPE space mission aims at testing the Equivalence Principle (EP) with an accuracy of 10-15. This principle is one of the basis of the General Relativity theory; it states the equivalence between gravitational and inertial mass. The test is based on the precise measurement of a gravitational signal by a differential electrostatic accelerometer which includes two cylindrical test masses made of different materials. The accelerometers constitute the payload accommodated on board a drag-free micro-satellite which is controlled inertial or rotating about the normal to the orbital plane. The acceleration estimates used for the EP test are disturbed by the instruments physical parameters and by the instrument environment conditions on-board the satellite. These parameters are partially measured with ground tests or during the integration of the instrument in the satellite (alignment). Nevertheless, the ground evaluations are not sufficient with respect to the EP test accuracy objectives. An in-orbit calibration is therefore needed to characterize them finely. The calibration process for each parameter has been defined.

Electrostatically screened, voltage-controlled electrostatic chuck

DOEpatents

Klebanoff, Leonard Elliott

2001-01-01

Employing an electrostatically screened, voltage-controlled electrostatic chuck particularly suited for holding wafers and masks in sub-atmospheric operations will significantly reduce the likelihood of contaminant deposition on the substrates. The electrostatic chuck includes (1) an insulator block having a outer perimeter and a planar surface adapted to support the substrate and comprising at least one electrode (typically a pair of electrodes that are embedded in the insulator block), (2) a source of voltage that is connected to the at least one electrode, (3) a support base to which the insulator block is attached, and (4) a primary electrostatic shield ring member that is positioned around the outer perimeter of the insulator block. The electrostatic chuck permits control of the voltage of the lithographic substrate; in addition, it provides electrostatic shielding of the stray electric fields issuing from the sides of the electrostatic chuck. The shielding effectively prevents electric fields from wrapping around to the upper or front surface of the substrate, thereby eliminating electrostatic particle deposition.

Initial results for the silicon monolithically interconnected solar cell product

NASA Technical Reports Server (NTRS)

Dinetta, L. C.; Shreve, K. P.; Cotter, J. E.; Barnett, A. M.

1995-01-01

This proprietary technology is based on AstroPower's electrostatic bonding and innovative silicon solar cell processing techniques. Electrostatic bonding allows silicon wafers to be permanently attached to a thermally matched glass superstrate and then thinned to final thicknesses less than 25 micron. These devices are based on the features of a thin, light-trapping silicon solar cell: high voltage, high current, light weight (high specific power) and high radiation resistance. Monolithic interconnection allows the fabrication costs on a per watt basis to be roughly independent of the array size, power or voltage, therefore, the cost effectiveness to manufacture solar cell arrays with output powers ranging from milliwatts up to four watts and output voltages ranging from 5 to 500 volts will be similar. This compares favorably to conventionally manufactured, commercial solar cell arrays, where handling of small parts is very labor intensive and costly. In this way, a wide variety of product specifications can be met using the same fabrication techniques. Prototype solar cells have demonstrated efficiencies greater than 11%. An open-circuit voltage of 5.4 volts, fill factor of 65%, and short-circuit current density of 28 mA/sq cm at AM1.5 illumination are typical. Future efforts are being directed to optimization of the solar cell operating characteristics as well as production processing. The monolithic approach has a number of inherent advantages, including reduced cost per interconnect and increased reliability of array connections. These features make this proprietary technology an excellent candidate for a large number of consumer products.

Science Using an Electrostatic Levitation Furnace in the MUCAT Sector at the APS

NASA Technical Reports Server (NTRS)

Goldman, A.; Kelton, K. F.; Rogers, J. R.

2004-01-01

The original motivation for the construction of the BESL prototype was to obtain the first proof of a 50-year-old hypothesis regarding the solidification of liquid metals. Since the 1950s it has been known that under proper conditions liquid metals can be cooled below their melting temperature (undercooled) without crystallizing to the stable solid phase. In 1952 Frank proposed that this was because the atoms in the metallic liquid were arranged with the symmetry of an icosahedron, a Platonic solid consisting of 20 tetrahedra (4-sided pyramid-shaped polyhedra) arranged around a common center. Since this local atomic order is incompatible with the long-range translational periodicity of crystal phases, a barrier is formed to the formation of small regions of the crystal phase, the nucleation barrier. A proof of Frank's hypothesis required a direct correlation between measured icosahedral order in the undercooled liquid and the nucleation barrier. The tendency of sample containers to catalyze nucleation obscured this relation, requiring containerless techniques. Combining containerless processing techniques for electrostatically levitated droplets (ESL) with x-ray synchrotron methods, a team from Washington University, St. Louis, MO, NASA Marshall Space Flight Center, and MUCAT at the APS demonstrated an increasing icosahedral order in TiZrNi liquids with decreasing temperature below the melting temperature. The increased icosahedral order caused the transformation of the liquid to a metastable icosahedral quasicrystal phase, instead of the stable tetrahedrally-coordinated crystal intermetallic, giving the first clear demonstration of the connection between the nucleation barrier and the local structure of the liquid, verifying Frank's hypothesis for this alloy.

development of a neutral mass spectrometer dedicated to the analysis of planetary envelopes (NIMEIS)

NASA Astrophysics Data System (ADS)

Becker, J.

2012-12-01

LATMOS worked for several years on a newly designed instrument suitable for measuring neutral environments as rarefied exosphere of Mars, Venus, Europa, asteroids or Titan for example. This instrument NIMEIS for Neutral and Ion Mass and Energy Imaging Spectrometer has as main features the ability to measure low densities of neutral but also conduct an analysis of mass and energy in an energy range covering the thermal and suprathermal between ~ 1 eV and 20 eV far unexplored. My thesis is divided into two independent parts. First, we optimize the ionization source, that is an innovative concept, and secondly we design the optics of the instrument based on an electrostatic optimization. The ionization source is based on the use of carbon nanotubes and to extract the electrons and ionize the neutral. Employing this technology we can significantly reduce the power, because previously we were using heated filaments. We develop this technology in close collaboration with a laboratory Ajou University (South Korea) that provides us with carbon nanotubes. I did a simulation study of the mode of extraction of electrons from initial tests, from an assembly developed by our laboratory in South Korea. The instrument has been optimized so that the impact on the detector gives us the one hand the energy of the particle and on the other hand the mass of the particle simultaneously and in continuous time. I developed the optics of the instrument using an electrostatic optical software. A comprehensive numerical model has been defined and a prototype is being manufactured.

Suspended polytetrafluoroethylene nanostructure electret film in dual variable cavities for self-powered micro-shock sensing

NASA Astrophysics Data System (ADS)

Zhu, Jianxiong; Chen, Cong; Guo, Xiaoyu

2018-04-01

We report a suspended polytetrafluoroethylene (PTFE) nanostructure electret film in dual variable cavities for a self-powered micro-shock sensing application. The prototype contained series variable air cavities, a suspended nanostructure PTFE electret film and independent electrode films. The charges on the suspended nanostructure PTFE electret film provided the electrostatic field around the electret film in the series variable air cavities. When the reported device was driven by a micro-shock pressure, the inducted electrostatic charges on both the top and bottom electrodes would vary as the micro-shock pressing or releasing. Experimental results showed that the maximum of a short-circuit current density (J sc ) and an open-circuit voltage (V oc ) reached 3 ± 0.1 nA cm‑2 and 3.6 ± 0.1 V, respectively. It was found that the parameter J sc was more advantageous in identifying stronger shocks (parameter acceleration a bigger than 0.1 m s‑2), whereas the parameter V oc was more sensitive for weaker shocks, such as acceleration a smaller than 0.1 m s‑2. Moreover, finger continuous micro-shock pressure taps application was used to demonstrate the mechanical energy conversion performance with 4.5 ± 0.2 V open-circuit voltages. The research on the nanostructure electret PTFE film in series dual variable air cavities not only gave us a fresh idea about the principle and design of the shocking sensor, but also provided an easy fabrication and a low cost shocking sensor for the Internet of Things (IoT) systems.