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  • Electronics and Electrical Engineering  (179)
  • Chemistry
  • Fisheries
  • Inorganic Chemistry
  • 2005-2009  (227)
  • 1920-1924
  • 2008  (227)
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  • 2005-2009  (227)
  • 1920-1924
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  • 1
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    Programme Gestion Intégrée des Ressources Marines et Côtières, Dakar (Senegal)
    Publication Date: 2021-05-19
    Description: Fondée sur l'intégration des principes et démarqhes des sciences de l'information et de la communication avec ceux du marketing social et relationnel, la stratégie de communicaton du Programme Girmac se décline sous la forme d'une vision globale, des objectifs généraux, des cibles ainsi que des activités et outils spécifiques de communication
    Description: Published
    Description: Girmac. strategie de communication
    Keywords: Marine environment ; Communication ; Fisheries ; Communication ; Information scientists ; Communication systems ; Marine environment ; Fisheries ; Canoe fisheries
    Repository Name: AquaDocs
    Type: Journal Contribution
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  • 2
    Publication Date: 2021-05-19
    Description: The anthropogenic affectation was evaluated on the coast N of the Gulf of Batabanó in May 2003 (corresponding to the provinces of Matanzas and Havana), in areas located in the line of the coast. The results were compared with the historical information of the sector. In the coast N and the Ensenada of the Broa, the parameters oxygen saturation, DBO5 and DQO showed characteristic high values of eutrofication. The biggest contribution in the Cianoficies was in the near coastal areas to sources of organic contamination. In the case of the nutrients they show specific data of mesothrofic waters with tendency to the eutrofization and the silts presented a high affectation for toxic metals. The area near to Guanímar is distinguished to present conditions of organic contamination that favor heterothrofic conditions, corroborated by a prevalence of the processes of mineralization of the organic matter over primary production and lows values of fitoplankton concentration. On the contrary, in the region of Surgidero of Batabanó, the processes of synthesis of organic matter prevail suggested by a high primary production, and concentration of fitoplankton, with low breathing levels and mineralization of the organic matter, that indicates that the system is behaving autothrofically. In a general way, this sector is very affected by the anthropogenic impact. The information obtained is of great importance for the development of the fishing and tourist industries in the area.
    Description: Published
    Keywords: Phytoplankton ; Water quality ; Primary production ; Chemistry ; Environmental monitoring ; Phytoplankton ; Water quality ; Primary production ; Chemistry ; Environmental monitoring
    Repository Name: AquaDocs
    Type: Proceedings Paper
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  • 3
    Publication Date: 2021-05-19
    Description: Durante las últimas décadas se ha observado un incremento de la captura (descartada y retenida) de condrictios en las pesquerías artesanales e industriales, conjuntamente con un rápido crecimiento de las pesquerías no reguladas, lo cual ha ocasionado una disminución en muchas poblaciones de este grupo de peces en todos los mares del mundo. La sobrepesca y los elevados niveles de mortalidad ocasionados por la captura incidental, asi como la degradación y contaminación de áreas costeras donde se ubican las zonas de alimentación, reproducción y cría para muchas especies de condrictios, han colocado a este grupo de peces en una situación difícil. Estos hechos, combinados con el bajo potencial reproductivo y la estrategia de vida de la mayoría de las especies de condríctios, no permiten una recuperación de las poblaciones, cuando las mismas se ven enfrentadas a períodos de sobreexplotación. En las aguas de Uruguay ocurren aproximadamente 100 especies de condrictios, muchas de las cuales son capturadas por diferentes pesquerias, tanto de forma incidental como dirigida. Debido a la preocupación a nivel internacional sobre la sustentabilidad de las pesquerías de tiburones, la FAO en 1998 realizó una consulta internacional a expertos y desarrolló un “Plan de Acción Internacional para la Conservación y el Manejo de los Tiburones” (PAI - Tiburones), el cual fue adoptado en 1999. El objetivo del PAI - Tiburones es asegurar la conservación, el manejo y el uso sustentable a largo plazo de los tiburones. Al hacer referencia a “tiburones”, se incluyen a todos los condrictios (tiburones, batoideos y quimeras). Este documento se divide en dos Capítulos y cuatro Anexos. El primer capítulo incluye los objetivos del PAN - Condrictios Uruguay y las medidas propuestas para alcanzar los mismos. El segundo capítulo contiene un diagnóstico general de los condrictios, las pesquerías y el marco jurídico. Como anexos se incluyen una lista de especies de condrictios citadas para Uruguay junto a su status en las listas rojas de la UICN, una reseña biológica de las especies consideradas prioritaras, una lista de abreviaturas, y listas de instituciones y personas que participaron de las reuniones desarrolladas durante el proceso de elaboración del PAN – Condrictios Uruguay. Las medidas propuestas por el PAN - Condrictios Uruguay se deberán aplicar a todas las pesquerías efectuadas por buques de bandera uruguaya, incluso los que operan fuera de la zona económica exclusiva de Uruguay.
    Description: Published
    Description: chondrichthyan, legal norm
    Keywords: M42 ; Fisheries ; Fisheries ; Conservation
    Repository Name: AquaDocs
    Type: Book
    Format: 87
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  • 4
    Publication Date: 2021-05-19
    Description: La captura incidental en pesquerías comerciales ha sido identificada como una de las principales amenazas para la conservación de este grupo de aves, siendo los albatros (familia: Diomedeidae) y los petreles (familia: Procellariidae) las especies más afectadas. Debido a que los albatros y petreles presentan una gran longevidad y una baja fecundidad, pocas crías y un lento desarrollo, sus poblaciones son muy sensibles al aumento en la tasa de mortalidad causado por la captura incidental en las pesquerías. Anualmente son capturadas y muertas miles de aves marinas en las pesquerías comerciales que operan con diferentes configuraciones de palangre alrededor del mundo. Este arte, entre otras causas, está contribuyendo al descenso de varias poblaciones de albatros y preteles, configurando un claro riesgo de extinción de estas especies, si se permite que las tendencias actuales persistan. Las pesquerías de arrastre también interactúan con las aves marinas provocando la mortalidad de las mismas en un importante número. Otras pesquerías que capturan aves marinas son las que operan con redes de enmalle, redes de cerco y poteras. Respondiendo a la necesidad de reducir la mortalidad de aves marinas la Organización de las Naciones Unidas para la Agricultura y la Alimentación (FAO) desarrolló un Plan de Acción Internacional para Reducir la Captura Incidental de Aves Marinas en las Pesquerías de Palangre, el cual propicia la elaboración de Planes de Acción Nacionales en cada uno de sus países miembros. El objetivo del Plan de Acción Nacional – Aves Marinas de Uruguay es presentar un marco general que permita instrumentar medidas para la reducción de la captura incidental de aves marinas en todas las pesquerías de Uruguay.
    Description: Published
    Description: seabirds
    Keywords: M42 ; Fisheries ; Catching methods ; Fisheries
    Repository Name: AquaDocs
    Type: Book
    Format: 75
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  • 5
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    Publication Date: 2021-01-30
    Description: This document presents the Senegalese maritime fishing statistics in 2005 with the catch from the artisanal fisheries, the industrial fisheries as well as exports and the value of commercial coating.The document also informs on the number of estimated canoes , the estimated number of fishermen, consumption of fresh fish product and processed products. The document also shows fisheries statistics by marine areas.
    Description: Ministère de l'Economie Maritime, Direction des Pêches Maritimes, Dakar (Sénégal)
    Description: Published
    Description: statistique, pêche artisanale, pêche industrielle, commercialisation, pêche maritime, pêche par espéce
    Keywords: Demersal fisheries ; Fisheries ; Marine fisheries ; Pelagic fisheries ; Commercial fishing ; Artisanal fishing ; Cephalopod fisheries ; Demersal fisheries ; Fisheries ; Fishery statistics ; Fishing vessels statistics ; Marine fisheries ; Mollusc fisheries ; Pelagic fisheries ; Shrimp fisheries
    Repository Name: AquaDocs
    Type: Report
    Format: 110
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  • 6
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    Publication Date: 2021-01-30
    Description: This document presents the Senegalese maritime fishing statistics in 2004 with the catch from the artisanal fisheries, the industrial fisheries as well as exports and the value of commercial coating.The document also informs on the number of estimated canoes , the estimated number of fishermen, consumption of fresh fish product and processed products. The document also shows fisheries statistics by marine areas.
    Description: Ministère de l'Economie Maritime et des Transports Maritimes Internationaux, Direction des Pêches Maritimes, Dakar (Sénégal)
    Description: Published
    Description: statistique, pêche artisanale, pêche industrielle, commercialisation, pêche maritime, pêche par espéce
    Keywords: Fisheries ; Demersal fisheries ; Marine fisheries ; Marine resources ; Marketing ; Coastal fisheries ; Pelagic fisheries ; Multispecies fisheries ; Artisanal fishing ; Fish catch statistics ; Fisheries ; Coastal fisheries ; Demersal fisheries ; Pelagic fisheries ; Marine fisheries ; Marine molluscs ; Marine resources ; Marketing ; Capture fishery economics ; Multispecies fisheries
    Repository Name: AquaDocs
    Type: Report
    Format: 115
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  • 7
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    Publication Date: 2021-01-30
    Description: This document presents the Senegalese maritime fishing statistics in 2006 with the catch from the artisanal fisheries, the industrial fisheries as well as exports and the value of commercial coating.The document also informs on the number of estimated canoes , the estimated number of fishermen, consumption of fresh fish product and processed products. The document also shows fisheries statistics by marine areas.
    Description: Ministère de l'Economie Maritime, Direction des Pêches Maritimes, Dakar (Sénégal)
    Description: Published
    Description: statistique, pêche artisanale, pêche industrielle, commercialisation, pêche maritime,
    Keywords: Fisheries ; Demersal fisheries ; Fishery data ; Marine fisheries ; Coastal fisheries ; Commercial fishing ; Cephalopod fisheries ; Coastal fisheries ; Demersal fisheries ; Fisheries ; Fish catch statistics ; Fishery economics ; Fishery industry ; Fishery data ; Fishery statistics ; Fishing vessels statistics ; Marine fisheries
    Repository Name: AquaDocs
    Type: Report
    Format: 104
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  • 8
    Publication Date: 2022-05-25
    Description: Author Posting. © Elsevier B.V., 2008. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Harmful Algae 7 (2008): 772-781, doi:10.1016/j.hal.2008.03.002.
    Description: In this study, we develop a framework for measuring the value of harmful algal bloom (HAB) predictions. The framework captures the effects of both private and public responses to HABs. Using data from the New England nearshore commercial shellfish fishery and impact estimates for a large-scale HAB event in 2005, we illustrate how the potential value of HAB forecasts may be estimated. The results of our study suggest that the long-term value of a HAB prediction and tracking system for the Gulf of Maine is sensitive to the frequency of HAB events, the accuracy of predictions, the choice of HAB impact measures, and the effectiveness of public and private responses.
    Description: This paper is a result of research funded in part by the National Oceanic and Atmospheric Administration’s Coastal Ocean Program under award #NA04NOS4780270 to the Woods Hole Oceanographic Institution.
    Keywords: Harmful algal bloom (HAB) ; Red tide ; Fisheries ; Value of information ; Forecast ; Marine scientific research
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
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  • 9
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    Programme Gestion Intégrée des Ressources Marines et Côtières, Dakar (Senegal)
    Publication Date: 2021-05-19
    Description: Du 1er au 25 octobre 2006, une enquête auprés des pêcheurs du fleuve Sénégal a été conduite afin de recueillir des informations sur les populations de lamantins notamment entre Podor et Bakel. entre autres résultats, la mission a pu rencontré beaucoup de communautés de pêcheurs et observé le Trichechus senegalensis (nom scientifique de l'espéce). Nous reproduisons quasiment in extenso la note de synthèse que le Chef de mission a bien voulu mettre à la disposition des lecteurs de DIISO
    Description: Published
    Description: lamantin; Trichechus senegalensis
    Keywords: Fisheries ; Surveys ; Surveys ; Fisheries
    Repository Name: AquaDocs
    Type: Journal Contribution
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  • 10
    Publication Date: 2021-05-19
    Description: Supported by IOC/IODE
    Description: Document available in English
    Description: ASFA
    Keywords: Fisheries ; Aquatic sciences ; Fisheries ; Abstracts
    Repository Name: AquaDocs
    Format: 15
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  • 11
    Publication Date: 2008-02-16
    Description: The management and conservation of the world's oceans require synthesis of spatial data on the distribution and intensity of human activities and the overlap of their impacts on marine ecosystems. We developed an ecosystem-specific, multiscale spatial model to synthesize 17 global data sets of anthropogenic drivers of ecological change for 20 marine ecosystems. Our analysis indicates that no area is unaffected by human influence and that a large fraction (41%) is strongly affected by multiple drivers. However, large areas of relatively little human impact remain, particularly near the poles. The analytical process and resulting maps provide flexible tools for regional and global efforts to allocate conservation resources; to implement ecosystem-based management; and to inform marine spatial planning, education, and basic research.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Halpern, Benjamin S -- Walbridge, Shaun -- Selkoe, Kimberly A -- Kappel, Carrie V -- Micheli, Fiorenza -- D'Agrosa, Caterina -- Bruno, John F -- Casey, Kenneth S -- Ebert, Colin -- Fox, Helen E -- Fujita, Rod -- Heinemann, Dennis -- Lenihan, Hunter S -- Madin, Elizabeth M P -- Perry, Matthew T -- Selig, Elizabeth R -- Spalding, Mark -- Steneck, Robert -- Watson, Reg -- New York, N.Y. -- Science. 2008 Feb 15;319(5865):948-52. doi: 10.1126/science.1149345.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉National Center for Ecological Analysis and Synthesis, 735 State Street, Santa Barbara, CA 93101, USA. halpern@nceas.ucsb.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18276889" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Climate ; Conservation of Natural Resources ; *Ecosystem ; Fisheries ; *Human Activities ; Humans ; Mathematics ; Models, Theoretical ; Oceans and Seas
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 12
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2008-10-11
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Stone, Richard -- New York, N.Y. -- Science. 2008 Oct 10;322(5899):184. doi: 10.1126/science.322.5899.184.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18845724" target="_blank"〉PubMed〈/a〉
    Keywords: *Angiosperms ; Animals ; Biodiversity ; *Bivalvia ; China ; Cyprinidae ; *Ecosystem ; Eutrophication ; Fisheries ; *Fishes ; *Fresh Water ; Population Dynamics
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 13
    Publication Date: 2008-10-04
    Description: Atlantic bluefin tuna populations are in steep decline, and an improved understanding of connectivity between individuals from eastern (Mediterranean Sea) and western (Gulf of Mexico) spawning areas is needed to manage remaining fisheries. Chemical signatures in the otoliths of yearlings from regional nurseries were distinct and served as natural tags to assess natal homing and mixing. Adults showed high rates of natal homing to both eastern and western spawning areas. Trans-Atlantic movement (east to west) was significant and size-dependent, with individuals of Mediterranean origin mixing with the western population in the U.S. Atlantic. The largest (oldest) bluefin tuna collected near the northern extent of their range in North American waters were almost exclusively of western origin, indicating that this region represents critical habitat for the western population.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rooker, Jay R -- Secor, David H -- De Metrio, Gregorio -- Schloesser, Ryan -- Block, Barbara A -- Neilson, John D -- New York, N.Y. -- Science. 2008 Oct 31;322(5902):742-4. doi: 10.1126/science.1161473. Epub 2008 Oct 2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Marine Biology, Texas A&M University, 5007 Avenue U, Galveston, TX 77551, USA. rookerj@tamug.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18832611" target="_blank"〉PubMed〈/a〉
    Keywords: *Animal Migration ; Animals ; Atlantic Ocean ; Carbon Isotopes/analysis ; Ecosystem ; Fisheries ; *Homing Behavior ; Likelihood Functions ; Mediterranean Sea ; Otolithic Membrane/chemistry ; Oxygen Isotopes/analysis ; Population Density ; Population Dynamics ; Reproduction ; Tuna/growth & development/*physiology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 14
    Publication Date: 2008-12-20
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Whitfield, John -- New York, N.Y. -- Science. 2008 Dec 19;322(5909):1786-7. doi: 10.1126/science.322.5909.1786.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19095921" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Birds ; Climate ; Ecosystem ; Fisheries ; *Fishes ; *Food Chain ; Humans ; North Sea ; Nutritive Value ; Oceans and Seas ; Pacific Ocean ; Population Dynamics ; Predatory Behavior ; *Sea Lions ; Seawater ; Temperature
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 15
    Publication Date: 2018-06-11
    Description: Area array packages (AAPs) with 1.27 mm pitch have been the packages of choice for commercial applications; they are now starting to be implemented for use in military and aerospace applications. Thermal cycling characteristics of plastic ball grid array (PBGA) and chip scale package assemblies, because of their wide usage for commercial applications, have been extensively reported on in literature. Thermal cycling represents the on-off environmental condition for most electronic products and therefore is a key factor that defines reliability.However, very limited data is available for thermal cycling behavior of ceramic packages commonly used for the aerospace applications. For high reliability applications, numerous AAPs are available with an identical design pattern both in ceramic and plastic packages. This paper compares assembly reliability of ceramic and plastic packages with the identical inputs/outputs(I/Os) and pattern. The ceramic package was in the form of ceramic column grid array (CCGA) with 560 I/Os peripheral array with the identical pad design as its plastic counterpart.
    Keywords: Electronics and Electrical Engineering
    Type: Transactions On Components And Packaging Technologies (ISSN 1521-3331); Volume 31; No. 2; 285-296
    Format: text
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  • 16
    Publication Date: 2018-06-11
    Description: It has been observed that power MOSFETs can experience an SEGR and continue to function with altered parameters. We propose that there are three different types of SEGR modes; the micro-break, the thermal runaway, and the avalanche breakdown. Data that demonstrates these stages of device failure are presented as well as a proposed model for the micro-break. Brief discussions of the other modes, based on analysis combined with our interpretations of the older literature, are also given.
    Keywords: Electronics and Electrical Engineering
    Type: IEEE Transactions On Nuclear Science; Volume 55; No. 4; 2366-2375
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  • 17
    Publication Date: 2018-06-11
    Description: High density PWB (printed wiring board) with microvia technology is required for implementation of high density and high I/O area array packages (AAP). COTS (commercial off-the-shelf) AAP packaging technologies in high reliability versions with 1.27 mm pitch are now being considered for use in a number of NASA systems including Space Shuttle and Mars Rovers. NASA functional system designs are requiring more and more dense AAP packages and board space, which makes board microvia technology very attractive for effectively routing a large number of package inputs/outputs. However, the reliability of the fine feature microvias including via in pads is unknown for space applications. Understanding process and QA (quality assurance) indicators for reliability are important for low risk insertion of these newly available packages and PWBs. This paper presents literature search as well as test results for a high density board subjected to various thermal cycle and reflow profiles representative of tin-lead and lead-free solder reflow. Microvias sizes ranged from two to six mil with and without filling. Daisy chain microvias monitored during the test and PWBs were cross-sectioned to determine failure and locations. Optical and SEM photographs as well as resistance changes during cycling and Tg/Td (glass transition/decomposition temperature) characterisations are presented.
    Keywords: Electronics and Electrical Engineering
    Type: International Journal of Materials and Structural Integrity; Volume 2; Nos. 1/2; 47-63
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  • 18
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    In:  CASI
    Publication Date: 2018-08-10
    Description: SpaceWire spaceflight applications are growing steadily and the data protocol is well documented and standardized. Yet, unique requirements for various programs often make it necessary to deviate from the standard. The introduction of new technologies into the SpaceWire community can only serve to support increased technology growth. The physical layer is often overlooked as a critical component of the SpaceWire link but experience will show that in certain situations a good physical layer design may be crucial to the success of the program. The SpaceWire cable assembly, consisting of the SpaceWire connector and cable, is one of the components that may offer design variations.
    Keywords: Electronics and Electrical Engineering
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  • 19
    Publication Date: 2018-06-06
    Description: Spectrographic astronomy measurements in the near-infrared region will be done by functional two-dimensional microshutter arrays that are being fabricated at the NASA Goddard Space Flight Center for the James Webb Space Telescope (JWST). These micro-shutter arrays will represent the first mission-critical MEMS devices to be flown in space. JWST will use microshutter arrays to select focal plane object. 2-D programmable aperture masks of more than 200,000 elements select such space object. The use of silicon wafer material promises high efficiency and high contrast. Microshutter operation temperature is around 35K. Microshutter arrays are fabricated as close-packed silicon nitride membranes with a unit cell size of 105 x 204 micrometers. A layer of magnetic material is deposited onto each shutter. Individual shutters are equipped with a torsion flexure. Reactive ion etching (RIE) releases the shutters so they can open up to 90 degrees using the torsion flexure. Shutter rotation is initiated into a silicon support structure via an external magnetic field. Two electrically independent aluminum electrodes are deposited, one onto each shutter and another onto the support structure side-wall, permitting electrostatic latching and 2-D addressing to hold specific shutters open via external electronics.
    Keywords: Electronics and Electrical Engineering
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  • 20
    Publication Date: 2018-06-06
    Description: Four probe antennas transfer signals from waveguide to microstrip lines. The probes not only provide broadband impedance matching, but also thermally isolate waveguide and detector. In addition, we developed a new photonic waveguide choke joint design, with four-fold symmetry, to suppress power leakage at the interface. We have developed facilities to test superconducting circuit elements using a cryogenic microwave probe station, and more complete systems in waveguide. We used the ring resonator shown below to measure a dielectric loss tangent 〈 7x10(exp -4) over 10 - 45 GHz. We have combined component simulations to predict the overall coupling from waveguide modes to bolometers. The result below shows the planar circuit and waveguide interface can utilize the high beam symmetry of HE11 circular feedhorns with 〉 99% coupling efficiency over 30% fractional bandwidth.
    Keywords: Electronics and Electrical Engineering
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  • 21
    Publication Date: 2019-07-27
    Description: At an earlier conference we discussed a selection of the challenges for radiation testing of modern semiconductor devices focusing on state-of-the-art CMOS technologies. In this presentation, we extend this discussion focusing on the following areas: (1) Device packaging, (2) Evolving physical single even upset mechanisms, (3) Device complexity, and (4) the goal of understanding the limitations and interpretation of radiation testing results.
    Keywords: Electronics and Electrical Engineering
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  • 22
    Publication Date: 2019-07-19
    Description: There are complex structures for which the installation and positioning of the lightning protection system (LPS) cannot be done using the lightning protection standard guidelines. As a result, there are some "unprotected" or "exposed" areas. In an effort to quantify the lightning threat to these areas, a Monte Carlo statistical tool has been developed. This statistical tool uses two random number generators: a uniform distribution to generate the origin of downward propagating leaders and a lognormal distribution to generate the corresponding returns stroke peak currents. Downward leaders propagate vertically downward and their striking distances are defined by the polarity and peak current. Following the electrogeometrical concept, we assume that the leader attaches to the closest object within its striking distance. The statistical analysis is run for N number of years with an assumed ground flash density and the output of the program is the probability of direct attachment to objects of interest with its corresponding peak current distribution.
    Keywords: Electronics and Electrical Engineering
    Type: KSC-2008-149 , 3rd International Conference on Lightning Physics and Effects; Nov 16, 2008 - Nov 20, 2008; Florianopolis; Brazil
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  • 23
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    In:  Other Sources
    Publication Date: 2019-07-19
    Description: The dissipation mechanism of magnetic reconnection remains a subject of intense scientific interest. On one hand, one set of recent studies have shown that particle inertia-based processes, which include thermal and bulk inertial effects, provide the reconnection electric field in the diffusion region. On the other hand, a second set of studies emphasizes the role of wave-particle interactions in providing anomalous resistivity in the diffusion region. In this presentation, we present analytical theory results, as well as PIC simulations of guide-field magnetic reconnection. We will show that the thermal electron inertia-based dissipation mechanism, expressed through nongyrotropic electron pressure tensors, remains viable in three dimensions. We will demonstrate the thermal inertia effect through studies of electron distribution functions. Furthermore, we will show that the reconnection electric field provides a transient acceleration on particles traversing the inner reconnection region. This inertia1 effect can be described as a diffusion-like term of the current density, which matches key features of electron distribution functions.
    Keywords: Electronics and Electrical Engineering
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  • 24
    Publication Date: 2019-07-19
    Description: We provide an overview of the Vector Electric Field Instrument (VEFI) on the Air Force Communication/Navigation Outage Forecasting System (C/NOFS) satellite, a mission designed to understand, model, and forecast the presence of equatorial ionospheric irregularities. VEFI is a NASA GSFC instrument designed 1) to investigate the role of the ambient electric fields in initiating nighttime ionospheric density depletions and turbulence; 2) to determine the electric fields associated with abrupt, large amplitude, density depletions and 3) to quantify the spectrum of the wave electric fields and plasma densities (irregularities) associated with density depletions or Equatorial Spread-F. The VEFI instrument includes a vector electric field double probe detector, a Langmuir trigger probe, a flux gate magnetometer, a lightning detector and associated electronics. The heart of the instrument is the set of double probe detectors designed to measure DC and AC electric fields using 6 identical, mutually orthogonal, deployable 9.5 m booms tipped with 10 cm diameter spheres containing embedded preamplifiers. A description of the instrument and its sensors will be presented. If available, representative measurements will be provided.
    Keywords: Electronics and Electrical Engineering
    Type: 12th International Symposium on Equatorial Aeronomy (ISEA); May 18, 2008 - May 24, 2008; Crete; Greece
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  • 25
    facet.materialart.
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    In:  Other Sources
    Publication Date: 2019-07-13
    Description: Is Verification Acceleration Possible? - Increasing the visibility of the internal nodes of the FPGA results in much faster debug time - Forcing internal signals directly allows a problem condition to be setup very quickly center dot Is this all? - No, this is part of a comprehensive effort to improve the JPL FPGA design and V&V process.
    Keywords: Electronics and Electrical Engineering
    Type: Military and Aerospace Programmable Logic Devices (MAPLD) Conference; Sep 15, 2008 - Sep 18, 2008; Annapolis, MD; United States
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  • 26
    facet.materialart.
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    In:  CASI
    Publication Date: 2019-07-13
    Description: The primary'technical objective of this project is to undertake comprehensive testing to generate information on failure modes/criteria to better understand the reliability of: Packages (e.g., Thin Small Outline Package [TSOP], Ball Grid Array [BGA], Plastic Dual In-line Package [PDIPD assembled and reworked with lead-free alloys Packages (e.g., TSOP, BGA, PDIP) assembled and reworked with mixed (lead/lead-free) alloys.
    Keywords: Electronics and Electrical Engineering
    Type: KSC-2008-045 , Cleaner, Sustainable Industrial Materials and Processes (C.S.I.M.P.) Workshop; Mar 17, 2008 - Mar 20, 2008; Coronado, CA; United States
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  • 27
    Publication Date: 2019-07-13
    Description: Electrostatic charging of insulators is well known to pose potential threats to electronic systems under terrestrial systems. We were asked to evaluate potential hazards associated with replacement of an electronics board in the vacuum of space during the upcoming Hubble Service Repair mission in September 2008. A device called a "tribot" was built to simulate triboelectric charging of several insulators that are capable of contact charging against astronaut's gloves and suit materials. Materials were evaluated as the extent of not only the magnitude of electric fields generated by the frictional action, but also any resulting discharge which would be a source of EMI. Experimental results are quite surprising and unexpected when compared with tests performed under ambient conditions under dry and humid air.
    Keywords: Electronics and Electrical Engineering
    Type: KSC-2008-070 , International ESD Workshop; May 12, 2008 - May 15, 2008; Port d''Albret; France
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  • 28
    Publication Date: 2019-07-13
    Description: Future NASA missions are increasingly seeking to actuate mechanisms to precision levels in the nanometer range and below. Co-fired multilayer piezoelectric stacks offer the required actuation precision that is needed for such mechanisms. To obtain performance statistics and determine reliability for extended use, sets of commercial PZT stacks were tested in various AC and DC conditions at both nominal and high temperatures and voltages. In order to study the lifetime performance of these stacks, five actuators were driven sinusoidally for up to ten billion cycles. An automated data acquisition system was developed and implemented to monitor each stack's electrical current and voltage waveforms over the life of the test. As part of the monitoring tests, the displacement, impedance, capacitance and leakage current were measured to assess the operation degradation. This paper presents some of the results of this effort.
    Keywords: Electronics and Electrical Engineering
    Type: ASCE American Society of Civil Engineers, Earth and Science 2008; Mar 03, 2008; Long Beach, CA; United States
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  • 29
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Electronics and Electrical Engineering
    Type: KSC-2008-275 , NASA-DoD Lead-Free Electronics Project Consortium; Dec 16, 2008; Kennedy Space Center, FL; United States
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  • 30
    Publication Date: 2019-07-12
    Description: New techniques for evaluating the incendiary behavior of insulators is presented. The onset of incendive brush discharges in air is evaluated using standard spark probe techniques for the case simulating approaches of an electrically grounded sphere to a charged insulator in the presence of a flammable atmosphere. However, this standard technique is unsuitable for the case of brush discharges that may occur during the charging-separation process for two insulator materials. We present experimental techniques to evaluate this hazard in the presence of a flammable atmosphere which is ideally suited to measure the incendiary nature of micro-discharges upon separation, a measurement never before performed. Other measurement techniques unique to this study include; surface potential measurements of insulators before, during and after contact and separation, as well as methods to verify fieldmeter calibrations using a charge insulator surface opposed to standard high voltage plates. Key words: Kapton polyimide film, incendiary discharges, brush discharges, contact and frictional electrification, ignition hazards, insulators, contact angle, surface potential measurements.
    Keywords: Electronics and Electrical Engineering
    Type: KSC-2008-013
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  • 31
    Publication Date: 2019-07-12
    Description: During the eight weeks working at NASA, I was fortunate enough to work with the Expendable Launch Vehicle's (ELV) Electromagnetic Compatibility (EMC) Team, who is responsible for the evaluation and analysis of any EMI risk an ELV mission might face. This group of people concern themselves with practically any form of electromagnetic interference that may risk the safety of a rocket, a mission, or even people. Taking this into consideration, the group investigates natural forms of interference, such as lightning, to manmade interferences, such as antennas.
    Keywords: Electronics and Electrical Engineering
    Type: KSC-2008-192
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  • 32
    Publication Date: 2019-07-12
    Description: Existing risk simulations make the assumption that when a free tin whisker has bridged two adjacent exposed electrical conductors, the result is an electrical short circuit. This conservative assumption is made because shorting is a random event that has a currently unknown probability associated with it. Due to contact resistance electrical shorts may not occur at lower voltage levels. In this experiment, we study the effect of varying voltage on the breakdown of the contact resistance which leads to a short circuit. From this data we can estimate the probability of an electrical short, as a function of voltage, given that a free tin whisker has bridged two adjacent exposed electrical conductors. Also, three tin whiskers grown from the same Space Shuttle Orbiter card guide used in the aforementioned experiment were cross-sectioned and studied using a focused ion beam (FIB). The rare polycrystalline structure seen in the FIB cross section was confirmed using transmission electron microscopy (TEM). The FIB was also used to cross section two card guides to facilitate the measurement of the grain size to determine that the tin plating on the card guides had a bright finish.
    Keywords: Electronics and Electrical Engineering
    Type: KSC-2008-017
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  • 33
    Publication Date: 2019-07-12
    Description: Existing risk simulations make the assumption that when a free tin whisker has bridged two adjacent exposed electrical conductors, the result is an electrical short circuit. This conservative assumption is made because shorting is a random event that has a currently unknown probability associated with it. Due to contact resistance, electrical shorts may not occur at lower voltage levels. In this experiment, we study the effect of varying voltage on the breakdown of the contact resistance which leads to a short circuit. From this data, we can estimate the probability of an electrical short, as a function of voltage, given that a free tin whisker has bridged two adjacent exposed electrical conductors. In addition, three tin whiskers grown from the same Space Shuttle Orbiter card guide used in the aforementioned experiment were cross sectioned and studied using a focused ion beam (FIB).
    Keywords: Electronics and Electrical Engineering
    Type: KSC-2008-269
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  • 34
    Publication Date: 2019-07-12
    Description: In this experiment, an empirical model to quantify the probability of occurrence of an electrical short circuit from tin whiskers as a function of voltage was developed. This model can be used to improve existing risk simulation models FIB and TEM images of a tin whisker confirm the rare polycrystalline structure on one of the three whiskers studied. FIB cross-section of the card guides verified that the tin finish was bright tin.
    Keywords: Electronics and Electrical Engineering
    Type: KSC-2008-034
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  • 35
    Publication Date: 2019-07-12
    Description: Existing risk simulations make the assumption that when a free tin whisker has bridged two adjacent exposed electrical conductors, the result is an electrical short circuit. This conservative assumption is made because shorting is a random event that has a currently unknown probability associated with it. Due to contact resistance electrical shorts may not occur at lower voltage levels. In this experiment, we study the effect of varying voltage on the breakdown of the contact resistance which leads to a short circuit. From this data we can estimate the probability of an electrical short, as a function of voltage, given that a free tin whisker has bridged two adjacent exposed electrical conductors. Also, three tin whiskers grown from the same Space Shuttle Orbiter card guide used in the aforementioned experiment were cross-sectioned and studied using a focused ion beam (FIB). The rare polycrystalline structure seen in the FIB cross section was confirmed using transmission electron microscopy (TEM). The FIB was also used to cross section two card guides to facilitate the measurement of the grain size to determine that the tin plating on the card guides had a bright finish.
    Keywords: Electronics and Electrical Engineering
    Type: KSC-2008-017 , KSC-2008-017R
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  • 36
    facet.materialart.
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    In:  CASI
    Publication Date: 2019-07-12
    Description: The Electrical Power Distribution Control Team takes on the task of determining power failures throughout the Orbiter. The Displays and Controls Team takes on the task of determining distribution, circuit breakers, and switch failures that might occur on the Orbiter or displays that stop working. This paper will identify the circuit packages I have put together for the D&C group, the redesigning of a Hybrid Driver Controller box, and the web designing the Displays and Controls website for easier access to information which can range from indicators to switches.
    Keywords: Electronics and Electrical Engineering
    Type: KSC-2008-284
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  • 37
    Publication Date: 2019-07-19
    Description: We provide an overview of the Vector Electric Field Investigation (VEFI) on the Air Force Communication/Navigation Outage Forecasting System (C/NOFS) satellite, a mission designed to understand, model, and forecast the presence of equatorial ionospheric irregularities. VEFI is a NASA/GSFC instrument funded by the Air Force Research Laboratory whose main objectives are to: 1) investigate the role of the ambient electric fields in initiating nighttime ionospheric density depletions and turbulence; 2) determine the quasi-DC electric fields associated with abrupt, large amplitude, density depletions, and 3) quantify the spectrum of the wave electric fields and plasma densities (irregularities) associated with density depletions typically referred to as equatorial spread-F. The VEFI instrument includes a vector electric field double probe detector, a fixed-bias Langmuir probe operating in the ion saturation regime, a flux-gate magnetometer, an optical lightning detector, and associated electronics. The heart of the instrument is the set of detectors designed to measure DC and AC electric fields using 6 identical booms that provide 3 axis, 20-m tip-to-tip orthogonal double probes. Each probe extends a 10 cm diameter sphere containing an embedded preamplifier. VEFI also includes a burst memory that enables snapshots of data from 1-8 channels of selected instruments to be sampled at rates of up to 32 kHz each. The bursts may be triggered by the detection of density depletions, intense electric field wave activity in a given band, lightning detector pulses, or an event at a pre-determined time or location. All VEFI instrument components are working exceptionally well. A description of the instrument, its sensors, and their sampling frequencies and sensitivities will be presented. Representative measurements will be shown.
    Keywords: Electronics and Electrical Engineering
    Type: 2008 AGU General Assembly; Dec 14, 2008 - Dec 20, 2008; San Francisco, CA; United States
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  • 38
    Publication Date: 2019-07-13
    Description: This paper proposes a technique to design a compact planar broadband microwave blocking filter. The filter is constructed from multiple sections of bandstop filters with means to control radiation loss. As a result, the filter has small physical size and provides multi-decade of suppression frequency bandwidth. The total length is less than half-wavelength long at the 3-dB corner frequency of 1.45 GHz. The experimental results show that the microstrip microwave blocking filter can provide an attenuation of more than 70 dB from 7 GHz to 39.5GHz with the total DC capacitance of les than 23 pF.
    Keywords: Electronics and Electrical Engineering
    Type: LEGNEW-OLDGSFC-GSFC-LN-1032 , European Microwave Conference; Oct 27, 2008 - Oct 31, 2008; Amsterdam; Netherlands|European Radar Conference (EuRAD); Oct 30, 2008 - Oct 31, 2008; Amsterdam; Netherlands
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  • 39
    Publication Date: 2019-07-19
    Description: Spacecraft dielectric charging, sometimes called deep-dielectric-charging or bulk-charging, occurs when high energy electrons imbed themselves in dielectric materials, and the charge density builds up, sometimes to breakdown levels. Charges usually bleed off slowly due to material conductivity. At very low (cryogenic) temperatures, the dielectric conductivity decreases until charges may remain and build up over weeks, months, or years. In those cases, the guidelines given in NASA and industry documents for when dielectric charging may become important are misleading. Arcing tests of spacecraft cables at liquid nitrogen temperatures and very low flux levels have been done at NASA MSFC for the JWST Project. In this paper, we describe the results of those tests and analyze their important implications for cryogenic spacecraft cable design and construction.
    Keywords: Electronics and Electrical Engineering
    Type: 4th Space Environment Symposium; Jan 22, 2008 - Jan 23, 2008; Tokyo; Japan
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  • 40
    Publication Date: 2019-07-19
    Description: Having already developed a transition-edge-sensor (TES) microcalorimeter design that enables uniform and reproducible high spectral resolution (routinely better than 3 eV resolution at 6 keV) and is compatible with high fill-factor arrays, we are now working towards demonstrating this performance at high count rates and with the multiplexed read-out needed for instrumenting the Constellation-X X-ray Microcalorimeter Spectrometer (XMS) focal plane array. Design changes that increase the speed of the individual XMS pixels, such as lowering the heat capacity or increasing the thermal conductance of the link to the 50-mK heatsink, result in larger, faster signals, thus the coupling to the multiplexer and the overall bandwidth of the electronics must accommodate this increase in slew rate. In order to operate the array with high incident x-ray flux without unacceptable degradation of the spectral resolution, the magnitude of thermal and electrical crosstalk must be controlled. We will discuss recent progress in the thermal and electrical designs of our close-packed TES arrays, and we will present spectra acquired through the read-out chain from the multiplexer electronics, through the demultiplexer software, to real-time signal processing.
    Keywords: Electronics and Electrical Engineering
    Type: International Society for Optical Engineering (SPIE) Conference; Jun 23, 2008 - Jun 27, 2008; Marseilles; France
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  • 41
    Publication Date: 2019-07-19
    Description: The promise of photoelectric X-ray polarimetry has now been realized in laboratory demonstrations and may soon be used for astrophysical observations. Photoelectric polarimetry in gas filled proportional counters achieves high sensitivity through a combination of broad band width and good modulation. The band can be tuned by careful choice of gas composition and pressure. The measurements rely on imaging the tracks of photoelectrons. The initial direction of each track carries information about the electric field of the X-ray photon, and an ensemble of such measurements thus measures the net polarization of the source. A novel readout geometry using time projection chambers (TPC) allows deep (i.e. high efficiency) detectors, albeit without the ability to image the sky. Polarimeters which exploit the TPC geometry can be optimized for use behind telescopes, to study faint persistent sources, or as wide field of view instruments, designed to study bright transient events such as gamma-ray bursts or solar flares. We present the conceptual design of both types of TPC polarimeter. Recent laboratory results demonstrate that these polarimeters can achieve substantial gains in the polarization sensitivity achievable in experiments of modest size.
    Keywords: Electronics and Electrical Engineering
    Type: HEAD 2008; Mar 31, 2008 - Apr 03, 2008; United States
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  • 42
    Publication Date: 2019-08-26
    Description: Methods of fabricating nano-gap electrode structures in array configurations, and the structures so produced. The fabrication method involves depositing first and second pluralities of electrodes comprising nanowires using processes such as lithography, deposition of metals, lift-off processes, and chemical etching that can be performed using conventional processing tools applicable to electronic materials processing. The gap spacing in the nano-gap electrode array is defined by the thickness of a sacrificial spacer layer that is deposited between the first and second pluralities of electrodes. The sacrificial spacer layer is removed by etching, thereby leaving a structure in which the distance between pairs of electrodes is substantially equal to the thickness of the sacrificial spacer layer. Electrode arrays with gaps measured in units of nanometers are produced. In one embodiment, the first and second pluralities of electrodes are aligned in mutually orthogonal orientations.
    Keywords: Electronics and Electrical Engineering
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  • 43
    Publication Date: 2019-07-12
    Description: A hybrid piezoelectric energy harvesting transducer system includes: (a) first and second symmetric, pre-curved piezoelectric elements mounted separately on a frame so that their concave major surfaces are positioned opposite to each other; and (b) a linear piezoelectric element mounted separately on the frame and positioned between the pre-curved piezoelectric elements. The pre-curved piezoelectric elements and the linear piezoelectric element are spaced from one another and communicate with energy harvesting circuitry having contact points on the frame. The hybrid piezoelectric energy harvesting transducer system has a higher electromechanical energy conversion efficiency than any known piezoelectric transducer.
    Keywords: Electronics and Electrical Engineering
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  • 44
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    In:  Other Sources
    Publication Date: 2019-07-12
    Description: The purpose of this project is to characterize and correlate Electrostatic Discharge (ESD) sensitivity levels of an Integrated Circuit (IC) package using Transmission Line Pulse (TLP) and Human Body Model (HBM) methods. This characterization will be used as a baseline ESD sensitivity level to demonstrate improvement to the ESD sensitivity of the IC package through the use of EPI-FLO(Trade Mark) Polymer Voltage Suppression (PVS) protection devices developed and manufactured by Electronic Polymers, Inc. (EPI).
    Keywords: Electronics and Electrical Engineering
    Type: JPL-Publ-08-25
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  • 45
    Publication Date: 2019-07-12
    Description: Several improved designs for complementary metal oxide/semiconductor (CMOS) integrated-circuit image detectors have been developed, primarily to reduce dark currents (leakage currents) and secondarily to increase responses to blue light and increase signal-handling capacities, relative to those of prior CMOS imagers. The main conclusion that can be drawn from a study of the causes of dark currents in prior CMOS imagers is that dark currents could be reduced by relocating p/n junctions away from Si/SiO2 interfaces. In addition to reflecting this conclusion, the improved designs include several other features to counteract dark-current mechanisms and enhance performance.
    Keywords: Electronics and Electrical Engineering
    Type: NPO-41224 , NASA Tech Briefs, August 2008; 14-15
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  • 46
    Publication Date: 2019-07-12
    Description: A new version of the double-Y balun, transitioning from an unbalanced microstrip to a balanced coplanar strip (CPS) line, has been designed to feed a complementary spiral antenna with an input impedance of 100 Omega. The new double-Y balun transitions from a microstrip line with truncated ground plane to a CPS line. The balun does not employ CPW lines; hence, CPW bridges are not required at the junction. In addition, the balun does not exhibit CPW parasitic resonances, thereby improving passband performance. The new version of the double-Y balun is designed to feed a complementary spiral antenna. Panels on the right illustrate an expanded view of the balun junction. Preliminary voltage standing-wave ratio (VSWR) and insertion loss data are illustrated. Measured data were compared with numerical results computed using Momentum. It is seen that the balun exhibits a VSWR of less than 1.5 from 400 MHz to 8 GHz and a VSWR of less than 1.8 up to 13 GHz. The VSWR can be reduced further by reducing reflections from the balun junction and load resistor. Also, the balun is seen to exhibit an insertion loss of less than 1.5 dB up to 12 GHz. Further work involves characterizing the balun's performance when feeding a complementary spiral antenna.
    Keywords: Electronics and Electrical Engineering
    Type: NASA Tech Briefs, August 2008; 11-12
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  • 47
    Publication Date: 2019-07-12
    Description: A method of fabricating Bi(2-x)Sb(x)Te3-based thermoelectric microdevices involves a combination of (1) techniques used previously in the fabrication of integrated circuits and of microelectromechanical systems (MEMS) and (2) a relatively inexpensive MEMS-oriented electrochemical-deposition (ECD) technique. The present method overcomes the limitations of prior MEMS fabrication techniques and makes it possible to satisfy requirements.
    Keywords: Electronics and Electrical Engineering
    Type: NPO-30797 , NASA Tech Briefs, July 2008; 10-11
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  • 48
    Publication Date: 2019-07-12
    Description: Prototype logic gates made of n-channel junction field-effect transistors (JFETs) and epitaxial resistors have been demonstrated, with a view toward eventual implementation of digital logic devices and systems in silicon carbide (SiC) integrated circuits (ICs). This development is intended to exploit the inherent ability of SiC electronic devices to function at temperatures from 300 to somewhat above 500 C and withstand large doses of ionizing radiation. SiC-based digital logic devices and systems could enable operation of sensors and robots in nuclear reactors, in jet engines, near hydrothermal vents, and in other environments that are so hot or radioactive as to cause conventional silicon electronic devices to fail. At present, current needs for digital processing at high temperatures exceed SiC integrated circuit production capabilities, which do not allow for highly integrated circuits. Only single to small number component production of depletion mode n-channel JFETs and epitaxial resistors on a single substrate is possible. As a consequence, the fine matching of components is impossible, resulting in rather large direct-current parameter distributions within a group of transistors typically spanning multiples of 5 to 10. Add to this the lack of p-channel devices to complement the n-channel FETs, the lack of precise dropping diodes, and the lack of enhancement mode devices at these elevated temperatures and the use of conventional direct coupled and buffered direct coupled logic gate design techniques is impossible. The presented logic gate design is tolerant of device parameter distributions and is not hampered by the lack of complementary devices or dropping diodes. In addition to n-channel JFETs, these gates include level-shifting and load resistors (see figure). Instead of relying on precise matching of parameters among individual JFETS, these designs rely on choosing the values of these resistors and of supply potentials so as to make the circuits perform the desired functions throughout the ranges over which the parameters of the JFETs are distributed. The supply rails V(sub dd) and V(sub ss) and the resistors R are chosen as functions of the distribution of direct-current operating parameters of the group of transistors used.
    Keywords: Electronics and Electrical Engineering
    Type: LEW-18256-1 , NASA Tech Briefs, December 2008; 13-14
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  • 49
    Publication Date: 2019-07-12
    Description: A monolithic micro - wave integrated-circuit (MMIC) singlestage amplifier containing an InP-based high-electron-mobility transistor (HEMT) plus coplanar-waveguide (CPW) transmission lines for impedance matching and input and output coupling, all in a highly miniaturized layout as needed for high performance at operating frequencies of hundreds of gigahertz is described.
    Keywords: Electronics and Electrical Engineering
    Type: NPO-44962 , NASA Tech Briefs, July 2008; 13
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  • 50
    Publication Date: 2019-07-12
    Description: A second-harmonic generator (SHG) serves as the source of the visible laser beam in an onboard calibration scheme for NASA's planned Space Interferometry Mission (SIM), which requires an infrared laser beam and a visible laser beam coherent with the infrared laser beam. The SHG includes quasi-phase-matched waveguides made of MgO-doped, periodically poled lithium niobate, pigtailed with polarization- maintaining optical fibers. Frequency doubling by use of such waveguides affords the required combination of coherence and sufficient conversion efficiency for the intended application. The spatial period of the poling is designed to obtain quasi-phase- matching at a nominal middle excitation wavelength of 1,319.28 nm. The SHG is designed to operate at a warm bias (ambient temperature between 20 and 25 C) that would be maintained in its cooler environment by use of electric heaters; the heater power would be adjusted to regulate the temperature precisely and thereby maintain the required precision of the spatial period. At the state of development at the time of this reporting, the SHG had been packaged and subjected to most of its planned space-qualification tests.
    Keywords: Electronics and Electrical Engineering
    Type: NPO-45253 , NASA Tech Briefs, October 2008; 27
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  • 51
    Publication Date: 2019-07-12
    Description: A design modification and a fabrication process that implements the modification have been conceived to solve two problems encountered in the development of back-illuminated, back-sidethinned complementary metal oxide/ semiconductor (CMOS) image-detector integrated circuits. The two problems are (1) how to form metal electrical-contact pads on the back side that are electrically connected through the thickness in proper alignment with electrical contact points on the front side and (2) how to provide alignment keys on the back side to ensure proper registration of backside optical components (e.g., microlenses and/or color filters) with the front-side pixel pattern. The essence of the design modification is to add metal plugs that extend from the desired front-side locations through the thickness and protrude from the back side of the substrate. The plugs afford the required front-to-back electrical conduction, and the protrusions of the plugs serve as both the alignment keys and the bases upon which the back-side electrical-contact pads can be formed.
    Keywords: Electronics and Electrical Engineering
    Type: NPO-42839 , NASA Tech Briefs, July 2008; 12-13
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  • 52
    Publication Date: 2019-07-12
    Description: A proposed tool would be used to inspect alignments of mating twinaxial-connector assemblies on interconnecting wiring harnesses. More specifically, the tool would be used to inspect the alignment of each contact pin of each connector on one assembly with the corresponding socket in the corresponding connector on the other assembly. It is necessary to inspect the alignment because if mating of the assemblies is attempted when any pin/socket pair is misaligned beyond tolerance, the connection will not be completed and the dielectric material in the socket will be damaged (see Figure 1). Although the basic principle of the tool is applicable to almost any type of mating connector assemblies, the specific geometry of the tool must match the pin-and-socket geometry of the specific mating assemblies to be inspected. In the original application for which the tool was conceived, each of the mating assemblies contains eight twinaxial connectors; the pin diameter is 0.014 in. (.0.35 mm), and the maximum allowable pin/socket misalignment is 0.007 in. (.0.18 mm). Incomplete connections can result in loss of flight data within the functional path to the space shuttle crew cockpit displays. The tool (see Figure 2) would consist mainly of a transparent disk with alignment clocking tabs that can be fitted onto either connector assembly. Sets of circles or equivalent reference markings are affixed to the face of the tool, located at the desired positions of the mating contact pairs. An inspector would simply fit the tool onto a connector assembly, engaging the clocking tabs until the tool fits tightly. The inspector would then align one set of circles positioning a line of sight perpendicular to one contact within the connector assembly. Mis alignments would be evidenced by the tip of a pin contact straying past the inner edge of the circle. Socket contact misalignments would be evidenced by a crescent-shaped portion of the white dielectric appearing within the circle. The tool could include a variable magnifier plus an illuminator that could be configured so as not to cast shadows.
    Keywords: Electronics and Electrical Engineering
    Type: MSC-23757 , NASA Tech Briefs, October 2008; 21-22
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  • 53
    Publication Date: 2019-07-12
    Description: A proposed device for combining or switching electromagnetic beams would have three ports, would not contain any moving parts, and would be switchable among three operating states: Two of the ports would be for input; the remaining port would be for output. In one operating state, the signals at both input ports would be coupled through to the output port. In each of the other two operating states, the signal at only one input port would be coupled to the output port. The input port would be selected through choice of the operating state.
    Keywords: Electronics and Electrical Engineering
    Type: NPO-44316 , NASA Tech Briefs, November 2008; 11-12
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  • 54
    Publication Date: 2019-07-12
    Description: This design allows broadband power combining with high isolation between the H port and E port, and achieves a lower insertion loss than any other broadband planar magic-T. Passive micro wave/millimeter-wave signal power is combined both in-phase and out-of-phase at the ports, with the phase error being less than 1 , which is limited by port impedance. The in-phase signal combiner consists of two quarter-wavelength-long transmission lines combined at the microstrip line junction. The out-of-phase signal combiner consists of two half-wavelength-long transmission lines combined in series. Structural symmetry creates a virtual ground plane at the combining junction, and the combined signal is converted from microstrip line to slotline. Optimum realizable characteristic impedances are used so that the magic-T provides broadband response with low return loss. The magic-T is used in microwave and millimeter-wave frequencies, with the operating bandwidth being approximately 100 percent. The minimum isolation obtainable is 32 dB from port E to port H. The magic-T VSWR is less than 1.1 in the operating band. Operating temperature is mainly dependent on the variation in the dielectric constant of the substrate. Using crystallized substrate, the invention can operate in an extremely broad range of temperatures (from 0 to 400 K). It has a very high reliability because it has no moving parts and requires no maintenance, though it is desirable that the magic-T operate in a low-humidity environment. Fabrication of this design is very simple, using only two metallized layers. No bond wires, via holes, or air bridges are required. Additionally, this magic-T can operate as an individual component without auxiliary components.
    Keywords: Electronics and Electrical Engineering
    Type: GSC-15353-1 , NASA Tech Briefs, November 2008; 12
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  • 55
    Publication Date: 2019-07-12
    Description: Distributed control in a networked environment is an irreplaceable feature in systems with remote sensors and actuators. Although distributed control was not originally designed to be networked, usage of off-the-shelf networking technologies has become so prevalent that control systems are desired to have access mechanisms similar to computer networks. However, proprietary transducer interfaces for network communications and distributed control overwhelmingly dominate this industry. Unless the lack of compatibility and interoperability among transducers is resolved, the mature level of access (that computer networking can deliver) will not be achieved in such networked distributed control systems. Standardization of networked transducer interfaces will enable devices from different manufacturers to talk to each other and ensure their plug-and-play capability. One such standard is the suite of IEEE 1451 for sensor network communication and transducer interfaces. The suite not only provides a standard interface for smart transducers, but also outlines the connection of an NCAP (network capable application processor) and transducers (through a transducer interface module TIM). This paper presents the design of the compliance testing of IEEE 1451.1 (referred to as Dot1) compatible NCAP-to-NCAP communications on a link-layer independent medium. The paper also represents the first demonstration of NCAP-to-NCAP communications with Dot1 compatibility: a tester NCAP and an NCAP under test (NUT).
    Keywords: Electronics and Electrical Engineering
    Type: SSTI-2200-0105
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  • 56
    Publication Date: 2019-07-12
    Description: Differential cross sections for electromagnetic dissociation in nuclear collisions are calculated for the first time. In order to be useful for three - dimensional transport codes, these cross sections have been calculated in both the projectile and lab frames. The formulas for these cross sections are such that they can be immediately used in space radiation transport codes. Only a limited amount of data exists, but the comparison between theory and experiment is good.
    Keywords: Electronics and Electrical Engineering
    Type: NASA/TP-2008-215534 , L-19383
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  • 57
    Publication Date: 2019-07-12
    Description: A novel microwave Nondestructive Evaluation (NDE) sensor was developed in an attempt to increase the sensitivity of the microwave NDE method for detection of defects small relative to a wavelength. The sensor was designed on the basis of a negative index material (NIM) lens. Characterization of the lens was performed to determine its resonant frequency, index of refraction, focus spot size, and optimal focusing length (for proper sample location). A sub-wavelength spot size (3 dB) of 0.48 lambda was obtained. The proof of concept for the sensor was achieved when a fiberglass sample with a 3 mm diameter through hole (perpendicular to the propagation direction of the wave) was tested. The hole was successfully detected with an 8.2 cm wavelength electromagnetic wave. This method is able to detect a defect that is 0.037 lambda. This method has certain advantages over other far field and near field microwave NDE methods currently in use.
    Keywords: Electronics and Electrical Engineering
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  • 58
    Publication Date: 2019-07-12
    Description: In this work, we present an alternate set of basis functions, each defined over a pair of planar triangular patches, for the method of moments solution of electromagnetic scattering and radiation problems associated with arbitrarily-shaped, closed, conducting surfaces. The present basis functions are point-wise orthogonal to the pulse basis functions previously defined. The prime motivation to develop the present set of basis functions is to utilize them for the electromagnetic solution of dielectric bodies using a surface integral equation formulation which involves both electric and magnetic cur- rents. However, in the present work, only the conducting body solution is presented and compared with other data.
    Keywords: Electronics and Electrical Engineering
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  • 59
    Publication Date: 2019-07-12
    Description: In this work, we present a new set of basis functions, defined over a pair of planar triangular patches, for the solution of electromagnetic scattering and radiation problems associated with arbitrarily-shaped surfaces using the method of moments solution procedure. The basis functions are constant over the function subdomain and resemble pulse functions for one and two dimensional problems. Further, another set of basis functions, point-wise orthogonal to the first set, is also defined over the same function space. The primary objective of developing these basis functions is to utilize them for the electromagnetic solution involving conducting, dielectric, and composite bodies. However, in the present work, only the conducting body solution is presented and compared with other data.
    Keywords: Electronics and Electrical Engineering
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  • 60
    Publication Date: 2019-07-12
    Description: Matrix methods for solving integral equations via direct solve LU factorization are presently limited to weeks to months of very expensive supercomputer time for problems sizes of several hundred thousand unknowns. This report presents matrix LU factor solutions for electromagnetic scattering problems for problem sizes to one million unknowns with thousands of right hand sides that run in mere days on PC level hardware. This EM solution is accomplished by utilizing the numerical low rank nature of spatially blocked unknowns using the Adaptive Cross Approximation for compressing the rank deficient blocks of the system Z matrix, the L and U factors, the right hand side forcing function and the final current solution. This compressed matrix solution is applied to a frequency domain EM solution of Maxwell's equations using standard Method of Moments approach. Compressed matrix storage and operations count leads to orders of magnitude reduction in memory and run time.
    Keywords: Electronics and Electrical Engineering
    Type: NASA/CR-2008-215353
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  • 61
    Publication Date: 2019-07-12
    Description: Analysis and experimental measurement of the electromagnetic force loads on the hybrid rotor in a novel hybrid magnetic-bearing switched-reluctance motor (MBSRM) have been performed. A MBSRM has the combined characteristics of a switched-reluctance motor and a magnetic bearing. The MBSRM discussed in this report has an eight-pole stator and a six-pole hybrid rotor, which is composed of circular and scalloped lamination segments. The hybrid rotor is levitated using only one set of four stator poles, while a second set of four stator poles imparts torque to the scalloped portion of the rotor, which is driven in a traditional switched reluctance manner by a processor. Static torque and radial force analysis were done for rotor poles that were oriented to achieve maximum and minimum radial force loads on the rotor. The objective is to assess whether simple one-dimensional magnetic circuit analysis is sufficient for preliminary evaluation of this machine, which may exhibit strong three-dimensional electromagnetic field behavior. Two magnetic circuit geometries, approximating the complex topology of the magnetic fields in and around the hybrid rotor, were employed in formulating the electromagnetic radial force equations. Reasonable agreement between the experimental and the theoretical radial force loads predictions was obtained with typical magnetic bearing derating factors applied to the predictions.
    Keywords: Electronics and Electrical Engineering
    Type: NASA/TP--2008-214818 , E-15821-1
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  • 62
    Publication Date: 2019-07-12
    Description: Commercial silicon carbide and silicon Schottky barrier power diodes have been subjected to 203 MeV proton irradiation and the effects of the resultant displacement damage on the I-V characteristics have been observed. Changes in forward bias I-V characteristics are reported for fluences up to 4 x 10(exp 14) p/cm2. For devices of both material types, the series resistance is observed to increase as the fluence increases. The changes in series resistance result from changes in the free carrier concentration due to carrier removal by the defects produced. A simple model is presented that allows calculation of the series resistance of the device and then relates the carrier removal rate to the changes in series resistance. Using this model to calculate the carrier removal rate in both materials reveals that the carrier removal rate in silicon is less than that in silicon carbide, indicating that silicon is the more radiation tolerant material.
    Keywords: Electronics and Electrical Engineering
    Type: JPL-Publ-08-06
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  • 63
    Publication Date: 2019-07-12
    Description: Adding material enhancements to a terahertz traveling-wave tube amplifier is investigated. Isotropic dielectrics, negative-index metamaterials, and anisotropic crystals are simulated, and plans to increase the efficiency of the device are discussed. Early results indicate that adding dielectric to the curved sections of the serpentine-shaped slow-wave circuit produce optimal changes in the cold-test characteristics of the device and a minimal drop in operating frequency. Additional results suggest that materials with simultaneously small relative permittivities and electrical conductivities are best suited for increasing the efficiency of the device. More research is required on the subject, and recommendations are given to determine the direction.
    Keywords: Electronics and Electrical Engineering
    Type: NASA/TM-2008-215059 , E-16271
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  • 64
    Publication Date: 2019-07-12
    Description: Leading up to the Apollo missions the Extended Kalman Filter, a modified version of the Kalman Filter, was developed to estimate the state of a nonlinear system. Throughout the Apollo missions, Potter's Square Root Filter was used for lunar navigation. Now that NASA is returning to the Moon, the filters used during the Apollo missions must be compared to the filters that have been developed since that time, the Bierman-Thornton Filter (UD) and the Unscented Kalman Filter (UKF). The UD Filter involves factoring the covariance matrix into UDUT and has similar accuracy to the Square Root Filter; however it requires less computation time. Conversely, the UKF, which uses sigma points, is much more computationally intensive than any of the filters; however it produces the most accurate results. The Extended Kalman Filter, Potter's Square Root Filter, the Bierman-Thornton UD Filter, and the Unscented Kalman Filter each prove to be the most accurate filter depending on the specific conditions of the navigation system.
    Keywords: Electronics and Electrical Engineering
    Type: NASA/TM-2008-215152 , E-16352
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  • 65
    Publication Date: 2019-07-12
    Description: Real time battery impedance spectrum is acquired using one time record, Compensated Synchronous Detection (CSD). This parallel method enables battery diagnostics. The excitation current to a test battery is a sum of equal amplitude sin waves of a few frequencies spread over range of interest. The time profile of this signal has duration that is a few periods of the lowest frequency. The voltage response of the battery, average deleted, is the impedance of the battery in the time domain. Since the excitation frequencies are known, synchronous detection processes the time record and each component, both magnitude and phase, is obtained. For compensation, the components, except the one of interest, are reassembled in the time domain. The resulting signal is subtracted from the original signal and the component of interest is synchronously detected. This process is repeated for each component.
    Keywords: Electronics and Electrical Engineering
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  • 66
    Publication Date: 2019-07-12
    Description: Electronic systems in aerospace and in space exploration missions are expected to encounter extreme temperatures and wide thermal swings. To address the needs for extreme temperature electronics, research efforts exist at the NASA Glenn Research Center (GRC) to develop and evaluate electronics for extreme temperature operations, and to establish their reliability under extreme temperature operation and thermal cycling; conditions that are typical of both the aerospace and space environments. These efforts are supported by the NASA Fundamental Aeronautics/Subsonic Fixed Wing Program and by the NASA Electronic Parts and Packaging (NEPP) Program. This work reports on the results obtained on the development of a temperature sensor geared for use in harsh environments.
    Keywords: Electronics and Electrical Engineering
    Type: NASA/TM-2008-215160 , E-16402
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  • 67
    Publication Date: 2019-07-12
    Description: A temperature sensor based on a commercial-off-the-shelf (COTS) Silicon-on-Insulator (SOI) Timer was designed for extreme temperature applications. The sensor can operate under a wide temperature range from hot jet engine compartments to cryogenic space exploration missions. For example, in Jet Engine Distributed Control Architecture, the sensor must be able to operate at temperatures exceeding 150 C. For space missions, extremely low cryogenic temperatures need to be measured. The output of the sensor, which consisted of a stream of digitized pulses whose period was proportional to the sensed temperature, can be interfaced with a controller or a computer. The data acquisition system would then give a direct readout of the temperature through the use of a look-up table, a built-in algorithm, or a mathematical model. Because of the wide range of temperature measurement and because the sensor is made of carefully selected COTS parts, this work is directly applicable to the NASA Fundamental Aeronautics/Subsonic Fixed Wing Program--Jet Engine Distributed Engine Control Task and to the NASA Electronic Parts and Packaging (NEPP) Program. In the past, a temperature sensor was designed and built using an SOI operational amplifier, and a report was issued. This work used an SOI 555 timer as its core and is completely new work.
    Keywords: Electronics and Electrical Engineering
    Type: NASA/TM--2008-215159 , E-16401
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  • 68
    Publication Date: 2019-07-12
    Description: A sensor chip, comprising a flexible, polymer-based substrate, and at least one microfabricated sensor disposed on the substrate and including a conductive element. The at least one sensor comprises at least one of a tactile sensor and a flow sensor. Other embodiments of the present invention include sensors and/or multi-modal sensor nodes.
    Keywords: Electronics and Electrical Engineering
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  • 69
    Publication Date: 2019-07-12
    Description: A device for the transdermal delivery of a therapeutic agent to a biological subject that includes a first electrode comprising a first array of electrically conductive microprojections for providing electrical communication through a skin portion of the subject to a second electrode comprising a second array of electrically conductive microprojections. Additionally, a reservoir for holding the therapeutic agent surrounding the first electrode and a pulse generator for providing an exponential decay pulse between the first and second electrodes may be provided. A method includes the steps of piercing a stratum corneum layer of skin with two arrays of conductive microprojections, encapsulating the therapeutic agent into biocompatible charged carriers, surrounding the conductive microprojections with the therapeutic agent, generating an exponential decay pulse between the two arrays of conductive microprojections to create a non-uniform electrical field and electrokinetically driving the therapeutic agent through the stratum corneum layer of skin.
    Keywords: Electronics and Electrical Engineering
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  • 70
    Publication Date: 2019-07-12
    Description: A conductive atomic force microscopy (cAFM) technique which can concurrently monitor topography, charge transport, and electroluminescence with nanometer spatial resolution. This cAFM approach is particularly well suited for probing the electroluminescent response characteristics of operating organic light-emitting diodes (OLEDs) over short length scales.
    Keywords: Electronics and Electrical Engineering
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  • 71
    Publication Date: 2019-08-27
    Description: Input circuitry is provided for a high voltage operated radiation detector to receive pulses from the detector having a rise time in the range of from about one nanosecond to about ten nanoseconds. An integrator circuit, which utilizes current feedback, receives the incoming charge from the radiation detector and creates voltage by integrating across a small capacitor. The integrator utilizes an amplifier which closely follows the voltage across the capacitor to produce an integrator output pulse with a peak value which may be used to determine the energy which produced the pulse. The pulse width of the output is stretched to approximately 50 to 300 nanoseconds for use by subsequent circuits which may then use amplifiers with lower slew rates.
    Keywords: Electronics and Electrical Engineering
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  • 72
    Publication Date: 2019-08-27
    Description: A self-contained power controller having a power driver switch, programmable controller, communication port, and environmental parameter measuring device coupled to a controllable device. The self-contained power controller needs only a single voltage source to power discrete devices, analog devices, and the controlled device. The programmable controller has a run mode which, when selected, upon the occurrence of a trigger event changes the state of a power driver switch and wherein the power driver switch is maintained by the programmable controller at the same state until the occurrence of a second event.
    Keywords: Electronics and Electrical Engineering
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  • 73
    Publication Date: 2019-08-28
    Description: A light control device is formed by ferroelectric material and N electrodes positioned adjacent thereto to define an N-sided regular polygonal region or circular region there between where N is a multiple of four.
    Keywords: Electronics and Electrical Engineering
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  • 74
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-08-28
    Description: A magnetostrictive valve assembly includes a housing that defines a passage with a seat being formed therein. A magnetically-biased and axially-compressed magnetostrictive assembly slidingly fitted in the passage is configured as a hollow and open-ended conduit adapted to support a flow of a fluid therethrough. Current-carrying coil(s) disposed about the passage in the region of the magnetostrictive assembly generate a magnetic field in the passage when current flows through the coil(s). A hollow valve body with side ports is coupled on one end thereof to an axial end of the magnetostrictive assembly. The other end of the valve body is designed to seal with the seat formed in the housing's passage when brought into contact therewith.
    Keywords: Electronics and Electrical Engineering
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  • 75
    Publication Date: 2019-08-28
    Description: Pt/n.sup.-GaN Schottky barrier diodes are disclosed that are particularly suited to serve as ultra-violet sensors operating at wavelengths below 200 nm. The Pt/n.sup.-GaN Schottky barrier diodes have very large active areas, up to 1 cm.sup.2, which exhibit extremely low leakage current at low reverse biases. Very large area Pt/n.sup.-GaN Schottky diodes of sizes 0.25 cm.sup.2 and 1 cm.sup.2 have been fabricated from n.sup.-/n.sup.+ GaN epitaxial layers grown by vapor phase epitaxy on single crystal c-plane sapphire, which showed leakage currents of 14 pA and 2.7 nA, respectively for the 0.25 cm.sup.2 and 1 cm.sup.2 diodes both configured at a 0.5V reverse bias.
    Keywords: Electronics and Electrical Engineering
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  • 76
    Publication Date: 2019-08-28
    Description: A hybrid electromechanical actuator has two different types of electromechanical elements, one that expands in a transverse direction when electric power is applied thereto and one that contracts in a transverse direction when electric power is applied thereto. The two electromechanical elements are (i) disposed in relation to one another such that the transverse directions thereof are parallel to one another, and (ii) mechanically coupled to one another at least at two opposing edges thereof. Electric power is applied simultaneously to the elements.
    Keywords: Electronics and Electrical Engineering
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  • 77
    Publication Date: 2019-08-13
    Description: A miniaturized Schottky diode hydrogen and hydrocarbon sensor and the method of making same is disclosed and claimed. The sensor comprises a catalytic metal layer, such as palladium, a silicon carbide substrate layer and a thin barrier layer in between the catalytic and substrate layers made of palladium oxide (PdO(x)). This highly stable device provides sensitive gas detection at temperatures ranging from at least 450 to 600 C. The barrier layer prevents reactions between the catalytic metal layer and the substrate layer. Conventional semiconductor fabrication techniques are used to fabricate the small-sided sensors. The use of a thicker palladium oxide barrier layer for other semiconductor structures such as a capacitor and transistor structures is also disclosed.
    Keywords: Electronics and Electrical Engineering
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  • 78
    Publication Date: 2019-08-13
    Description: The National Aeronautics and Space Administration (NASA) is not required by United States or international law to use lead-free (Pb-free) electronic systems but international pressure in the world market is making it increasingly important that NASA have a Pb-free policy. In fact, given the international nature of the electronics market, all organizations need a Pb-free policy. This paper describes the factors which must be taken into account in formulating the policy, the tools to aid in structuring the policy and the unanticipated and difficult challenges encountered. NASA is participating in a number of forums and teams trying to develop effective approaches to controlling Pb-free adoption in high reliability systems. The activities and status of the work being done by these teams will be described. NASA also continues to gather information on metal whiskers, particularly tin based, and some recent examples will be shared. The current lack of a policy is resulting in "surprises" and the need to disposition undesirable conditions on a case-by-case basis. This is inefficient, costly and can result in sub-optimum outcomes.
    Keywords: Electronics and Electrical Engineering
    Type: TRISMAC 08 Joint NASA/ESA/JAXA Conference; Apr 14, 2008 - Apr 16, 2008; Noordwijk; Netherlands
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  • 79
    Publication Date: 2019-08-13
    Description: An apparatus is disclosed that includes a carrier structure and an optical coupling arrangement. The carrier structure is made of a silicon material and allows for the packaging and integrating of microphotonic devices onto a single chip. The optical coupling mechanism enables laser light to be coupled into and out of a microphotonic resonant disk integrated on the carrier. The carrier provides first, second and third cavities that are dimensioned so as to accommodate the insertion and snug fitting of the microphotonic resonant disk and first and second prisms that are implemented by the optical coupling arrangement to accommodate the laser coupling.
    Keywords: Electronics and Electrical Engineering
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  • 80
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-08-13
    Description: A system and method for hybrid power management. The system includes photovoltaic cells, ultracapacitors, and pulse generators. In one embodiment, the hybrid power management system is used to provide power for a highway safety flasher.
    Keywords: Electronics and Electrical Engineering
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  • 81
    Publication Date: 2019-07-13
    Description: In a previous work, the addition of basic screened Coulombic electrostatic forces to an existing commercial discrete element modeling (DEM) software was reported. Triboelectric experiments were performed to charge glass spheres rolling on inclined planes of various materials. Charge generation constants and the Q/m ratios for the test materials were calculated from the experimental data and compared to the simulation output of the DEM software. In this paper, we will discuss new values of the charge generation constants calculated from improved experimental procedures and data. Also, planned work to include dielectrophoretic, Van der Waals forces, and advanced mechanical forces into the software will be discussed.
    Keywords: Electronics and Electrical Engineering
    Type: KSC-2008-099 , ESA Annual Meeting on Electrostatics 2008; Sep 15, 2008 - Sep 17, 2008; Karlsruhe; Germany
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  • 82
    Publication Date: 2019-07-13
    Description: Accurate, on-board classification of instrument data is used to increase science return by autonomously identifying regions of interest for priority transmission or generating summary products to conserve transmission bandwidth. Due to on-board processing constraints, such classification has been limited to using the simplest functions on a small subset of the full instrument data. FPGA co-processor designs for SVM1 classifiers will lead to significant improvement in on-board classification capability and accuracy.
    Keywords: Electronics and Electrical Engineering
    Type: IEEEAC Paper 1230 , IEEE Aerospace Conference; Mar 06, 2008; Big Sky, MT; United States
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  • 83
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-07-13
    Description: Due to requirements for reduced size and weight, use of grid array packages in space applications has become common place. To meet the requirement of high reliability and high number of I/Os, ceramic column grid array packages (CCGA) were selected for major electronic components used in next MARS Rover mission (specifically high density Field Programmable Gate Arrays). ABSTRACT The probability of removal and replacement of these devices on the actual flight printed wiring board assemblies is deemed to be very high because of last minute discoveries in final test which will dictate changes in the firmware. The questions and challenges presented to the manufacturing organizations engaged in the production of high reliability electronic assemblies are, Is the reliability of the PWBA adversely affected by rework (removal and replacement) of the CGA package? and How many times can we rework the same board without destroying a pad or degrading the lifetime of the assembly? To answer these questions, the most complex printed wiring board assembly used by the project was chosen to be used as the test vehicle, the PWB was modified to provide a daisy chain pattern, and a number of bare PWB s were acquired to this modified design. Non-functional 624 pin CGA packages with internal daisy chained matching the pattern on the PWB were procured. The combination of the modified PWB and the daisy chained packages enables continuity measurements of every soldered contact during subsequent testing and thermal cycling. Several test vehicles boards were assembled, reworked and then thermal cycled to assess the reliability of the solder joints and board material including pads and traces near the CGA. The details of rework process and results of thermal cycling are presented in this paper.
    Keywords: Electronics and Electrical Engineering
    Type: Pan Pacific Microelectronics Symposium; Jan 01, 2008; Hawaii, HI; United States
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  • 84
    Publication Date: 2019-07-13
    Description: This viewgraph presentation reviews NASA's Electronic Parts and Packaging (NEPP) Program. The NEPP mission is to provide guidance to NASA for the selection and and application of microelectronics technologies, to improve understanding of the risks related to the use of these technologies in the space environment and to ensure that appropriate research is performed to meet NASA mission needs. The NEPP Program focuses on the reliability aspects of electronic devices. Three principal aspects to this reliability: (1) lifetime, (2) effects of space radiation and the space environment, and (3) creation and maintenance of the assurance support infrastructure required for success.
    Keywords: Electronics and Electrical Engineering
    Type: Single Event Effects Symposium (SEESYM); Apr 15, 2008 - Apr 17, 2008; Long Beach, CA; United States|Components for Military and Space Electronics (CMSE) conference; Feb 11, 2008 - Feb 14, 2008; San Diego, CA; United States|Hardened Electronics and Radiation Technology (HEART) conference; Mar 31, 2008 - Apr 04, 2008; Colorado Springs, CO; United States|IEEE Nuclear and Space Radiation Effects conference (NSREC); Jul 14, 2008 - Jul 18, 2008; Tucson, AZ; United States
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  • 85
    Publication Date: 2019-07-13
    Description: At GOMAC 2007, we discussed a selection of the challenges for radiation testing of modern semiconductor devices focusing on state-of-the-art memory technologies. This included FLASH non-volatile memories (NVMs) and synchronous dynamic random access memories (SDRAMs). In this presentation, we extend this discussion in device packaging and complexity as well as single event upset (SEU) mechanisms using several technology areas as examples including: system-on-a-chip (SOC) devices and photonic or fiber optic systems. The underlying goal is intended to provoke thought for understanding the limitations and interpretation of radiation testing results.
    Keywords: Electronics and Electrical Engineering
    Type: Government Microcircuit Applications and Critical Technology Conference (GOMAC); Mar 17, 2008 - Mar 20, 2008; Las Vegas, NV; United States
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  • 86
    Publication Date: 2019-07-13
    Description: NASA Hubble Space Telescope (HST) and upcoming cosmology science missions carry instruments with multiple focal planes populated with many large sensor detector arrays. These sensors are passively cooled to low temperatures for low-level light (L3) and near-infrared (NIR) signal detection, and the sensor readout electronics circuitry must perform at extremely low noise levels to enable new required science measurements. Because we are at the technological edge of enhanced performance for sensors and readout electronics circuitry, as determined by thermal noise level at given temperature in analog domain, we must find new ways of further compensating for the noise in the signal digital domain. To facilitate this new approach, state-of-the-art sensors are augmented at their array hardware boundaries by non-illuminated reference pixels, which can be used to reduce noise attributed to sensors. There are a few proposed methodologies of processing in the digital domain the information carried by reference pixels, as employed by the Hubble Space Telescope and the James Webb Space Telescope Projects. These methods involve using spatial and temporal statistical parameters derived from boundary reference pixel information to enhance the active (non-reference) pixel signals. To make a step beyond this heritage methodology, we apply the NASA-developed technology known as the Hilbert- Huang Transform Data Processing System (HHT-DPS) for reference pixel information processing and its utilization in reconfigurable hardware on-board a spaceflight instrument or post-processing on the ground. The methodology examines signal processing for a 2-D domain, in which high-variance components of the thermal noise are carried by both active and reference pixels, similar to that in processing of low-voltage differential signals and subtraction of a single analog reference pixel from all active pixels on the sensor. Heritage methods using the aforementioned statistical parameters in the digital domain (such as statistical averaging of the reference pixels themselves) zeroes out the high-variance components, and the counterpart components in the active pixels remain uncorrected. This paper describes how the new methodology was demonstrated through analysis of fast-varying noise components using the Hilbert-Huang Transform Data Processing System tool (HHT-DPS) developed at NASA and the high-level programming language MATLAB (Trademark of MathWorks Inc.), as well as alternative methods for correcting for the high-variance noise component, using an HgCdTe sensor data. The NASA Hubble Space Telescope data post-processing, as well as future deep-space cosmology projects on-board instrument data processing from all the sensor channels, would benefit from this effort.
    Keywords: Electronics and Electrical Engineering
    Type: Military and Aerospace Programmable Logic Devices (MAPLD-2008) Conference; Sep 15, 2008 - Sep 18, 2008; Annapolis, MD; United States
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  • 87
    Publication Date: 2019-07-13
    Description: A well-collapse source-injection mode for SRAM SEU is demonstrated through TCAD modeling. The recovery of the SRAM s state is shown to be based upon the resistive path from the p+-sources in the SRAM to the well. Multiple cell upset patterns for direct charge collection and the well-collapse source-injection mechanisms are then predicted and compared to recent SRAM test data.
    Keywords: Electronics and Electrical Engineering
    Type: Nuclear and Space Radiation Effects Conference (NSREC); Jul 14, 2008 - Jul 18, 2008; Tucson, AZ; United States
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  • 88
    Publication Date: 2019-07-13
    Description: The development of intelligent instrumentation systems is of high interest in both public and private sectors. In order to obtain this ideal in extreme environments (i.e., high temperature, extreme vibration, harsh chemical media, and high radiation), both sensors and electronics must be developed concurrently in order that the entire system will survive for extended periods of time. The semiconductor silicon carbide (SiC) has been studied for electronic and sensing applications in extreme environment that is beyond the capability of conventional semiconductors such as silicon. The advantages of SiC over conventional materials include its near inert chemistry, superior thermomechanical properties in harsh environments, and electronic properties that include high breakdown voltage and wide bandgap. An overview of SiC sensors and electronics work ongoing at NASA Glenn Research Center (NASA GRC) will be presented. The main focus will be two technologies currently being investigated: 1) harsh environment SiC pressure transducers and 2) high temperature SiC electronics. Work highlighted will include the design, fabrication, and application of SiC sensors and electronics, with recent advancements in state-of-the-art discussed as well. These combined technologies are studied for the goal of developing advanced capabilities for measurement and control of aeropropulsion systems, as well as enhancing tools for exploration systems.
    Keywords: Electronics and Electrical Engineering
    Type: 54th International Instrumentation Symposium; May 05, 2008 - May 08, 2008; Florida; United States
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  • 89
    Publication Date: 2019-07-13
    Description: An actively pumped alkali metal flow circuit, designed and fabricated at the NASA Marshall Space Flight Center, underwent a range of tests at MSFC in early 2007. During this period, system transient responses and the performance of the liquid metal pump were evaluated. In May of 2007, the circuit was drained and cleaned to prepare for multiple modifications: the addition of larger upper and lower reservoirs, the installation of an annular linear induction pump (ALIP), and the inclusion of a closeable orifice in the test section. Modifications are now complete and testing has resumed. Performance of the ALIp, provided by Idaho National Laboratory (INL), is the subject of the first round ofexperimentation. This paper provides a summary of the tests conducted on the original circuit, details the physical changes that have since been made to it, and describes the current test program.
    Keywords: Electronics and Electrical Engineering
    Type: 2008 International Congress on Advances in Nuclear Power Plants (ICAPP); Jun 08, 2008 - Jun 12, 2008; Anaheim, CA; United States
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  • 90
    Publication Date: 2019-07-13
    Description: We present the final configuration of the space flight laser transmitter as delivered to the LOLA instrument. The laser consists of two oscillators with co-aligned outputs on a single bench, each capable of providing one billion plus shots.
    Keywords: Electronics and Electrical Engineering
    Type: Photonics West 2008; Jan 19, 2008 - Jan 24, 2008; California; United States
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  • 91
    Publication Date: 2019-07-13
    Description: The lifetime of a patterned carbon nanotube film is evaluated for use as the cold cathode field emission ionization source of a miniaturized mass spectrometer. Emitted current is measured as a function of time for varying partial pressures of nitrogen gas to explore the robustness and lifetime of carbon nanotube cathodes near the expected operational voltages (70-100 eV) for efficient ionization in mass spectrometry. As expected, cathode lifetime scales inversely with partial pressure of nitrogen. Results are presented within the context of previous carbon nanotube investigations, and implications for planetary science mass spectrometry applications are discussed.
    Keywords: Electronics and Electrical Engineering
    Type: Society of Photo-Optical Instrumentation Engineers Defense and Security Symposium; Mar 17, 2008 - Mar 20, 2008; Orlando, FL; United States
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  • 92
    Publication Date: 2019-07-13
    Description: Measurements of the complex. dielectric constant of seawater at 30.00 psu, 35.00 psu and 38.27 psu over the temperature range from 5 C to 3 5 at 1.413 GHz are given and compared with the Klein-Swift results. A resonant cavity technique is used. The calibration constant used in the cavity perturbation formulas is determined experimentally using methanol and ethanediol (ethylene glycol) as reference liquids. Analysis of the data shows that the measurements are accurate to better than 1.0% in almost all cases studied.
    Keywords: Electronics and Electrical Engineering
    Type: IGARSS 08; Jul 07, 2008 - Jul 11, 2008; Boston, MA; United States
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  • 93
    Publication Date: 2019-07-13
    Description: Scintillations in solid tantalum capacitors are momentarily local breakdowns terminated by a self-healing or conversion to a high-resistive state of the manganese oxide cathode. This conversion effectively caps the defective area of the tantalum pentoxide dielectric and prevents short-circuit failures. Typically, this type of breakdown has no immediate catastrophic consequences and is often considered as nuisance rather than a failure. Scintillation breakdowns likely do not affect failures of parts under surge current conditions, and so-called "proofing" of tantalum chip capacitors, which is a controllable exposure of the part after soldering to voltages slightly higher than the operating voltage to verify that possible scintillations are self-healed, has been shown to improve the quality of the parts. However, no in-depth studies of the effect of scintillations on reliability of tantalum capacitors have been performed so far. KEMET is using scintillation breakdown testing as a tool for assessing process improvements and to compare quality of different manufacturing lots. Nevertheless, the relationship between failures and scintillation breakdowns is not clear, and this test is not considered as suitable for lot acceptance testing. In this work, scintillation breakdowns in different military-graded and commercial tantalum capacitors were characterized and related to the rated voltages and to life test failures. A model for assessment of times to failure, based on distributions of breakdown voltages, and accelerating factors of life testing are discussed.
    Keywords: Electronics and Electrical Engineering
    Type: Electronic Devices and Systems IMAPS CS International Conference; Sep 10, 2008 - Sep 11, 2008; Brno; Czech Republic
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  • 94
    Publication Date: 2019-07-13
    Description: This viewgraph presentation reviews the inspection techniques for Column Grid Array (CGA) packages. The CGA is a method of chip scale packaging using high temperature solder columns to attach part to board. It is becoming more popular over other techniques (i.e. quad flat pack (QFP) or ball grid array (BGA)). However there are environmental stresses and workmanship challenges that require good inspection techniques for these packages.
    Keywords: Electronics and Electrical Engineering
    Type: Military, Aerospace, Space and Homeland Security (MASH): Packaging Issues and Applications; Apr 29, 2008 - Apr 30, 2008; Linthicum Heights, MD; United States
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  • 95
    Publication Date: 2019-07-13
    Description: Radio frequency (RF) microelectromechanical (MEMS) switches offer superior performance when compared to the traditional semiconductor devices such as PIN diodes or GaAs transistors. MEMS switches have a return loss (RL) better than -25 dB, negligible insertion loss (IL), isolation better than -30 dB, and near zero power consumption. However, RF MEMS switches have several drawbacks the most serious being long-term reliability. The ability for the switch to operate for millions or even billions of cycles is a major concern and must be addressed. MEMS switches are basically grouped in two categories, capacitive and metal-to-metal contact. The capacitive type switch consists of a movable metal bridge spanning a fixed electrode and separated by a narrow air gap and thin insulating material. The metal-to-metal contact type utilizes the same basic design but without the insulating material. After prolonged operation the metal bridges, in most of these switches, begin to sag and eventually fail to actuate. For the metal-to-metal type, the two metal layers may actually fuse together. Also if the switches are not packaged properly or protected from the environment moisture may build up and cause stiction between the top and bottom electrodes rendering them useless. Many MEMS switch designs have been developed and most illustrate fairly good RF characteristics. Nevertheless very few have demonstrated both great RF performance and ability to perform millions/billions of switching cycles. Of these, nearly all are of metal-to-metal type so as the frequency increases RF performance decreases.
    Keywords: Electronics and Electrical Engineering
    Type: NASA/TM-2008-215201 , E-16472 , IEEE Paper 2961 , IEEE Antennas and Propagation; Jul 05, 2008 - Jul 12, 2008; San Diego, CA; United States
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  • 96
    Publication Date: 2019-07-13
    Description: The fabrication and testing of the first semiconductor transistors and small-scale integrated circuits (ICs) to achieve up to 3000 h of stable electrical operation at 500 C in air ambient is reported. These devices are based on an epitaxial 6H-SiC junction field-effect transistor process that successfully integrated high temperature ohmic contacts, dielectric passivation, and ceramic packaging. Important device and circuit parameters exhibited less than 10% of change over the course of the 500 C operational testing. These results establish a new technology foundation for realizing durable 500 C ICs for combustion-engine sensing and control, deep-well drilling, and other harsh-environment applications.
    Keywords: Electronics and Electrical Engineering
    Type: WO-667844 , IEEE Electron Device Letters; 29; 5; 456-459
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  • 97
    Publication Date: 2019-07-13
    Description: This paper presents investigations to date on chemical detection using a recently developed method for designing, powering and interrogating sensors as electrically open circuits having no electrical connections. In lieu of having each sensor from a closed circuit with multiple electrically connected components, an electrically conductive geometric pattern that is powered using oscillating magnetic fields and capable of storing an electric field and a magnetic field without the need of a closed circuit or electrical connections is used. When electrically active, the patterns respond with their own magnetic field whose frequency, amplitude and bandwidth can be correlated with the magnitude of the physical quantities being measured. Preliminary experimental results of using two different detection approaches will be presented. In one method, a thin film of a reactant is deposited on the surface of the open-circuit sensor. Exposure to a specific targeted reactant shifts the resonant frequency of the sensor. In the second method, a coating of conductive material is placed on a thin non-conductive plastic sheet that is placed over the surface of the sensor. There is no physical contact between the sensor and the electrically conductive material. When the conductive material is exposed to a targeted reactant, a chemical reaction occurs that renders the material non-conductive. The change in the material s electrical resistance within the magnetic field of the sensor alters the sensor s response bandwidth and amplitude, allowing detection of the reaction without having the reactants in physical contact with the sensor.
    Keywords: Electronics and Electrical Engineering
    Type: LF99-6745 , IEEE Sensors 2008; Oct 26, 2008 - Oct 29, 2008; Leece; Italy
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  • 98
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    In:  CASI
    Publication Date: 2019-07-13
    Description: This paper illustrates using Markov models to establish system and maintenance requirements for small electronic controllers where the goal is a high probability of continuous service for a long period of time. The system and maintenance items considered are quality of components, various degrees of simple redundancy, redundancy with reconfiguration, diagnostic levels, periodic maintenance, and preventive maintenance. Markov models permit a quantitative investigation with comparison and contrast. An element of special interest is the use of conditional probability to study the combination of imperfect diagnostics and periodic maintenance.
    Keywords: Electronics and Electrical Engineering
    Type: 27th Digital Avionics Systems Conference; Oct 26, 2008 - Oct 30, 2008; Saint Paul, MN; United States
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  • 99
    Publication Date: 2019-07-13
    Description: This purpose of this viewgraph presentation is to discuss failures in hermetic hybrids observed at the GSFC PA Lab during environmental stress testing. The cases discussed are: Case I. Substrate metallization failures during Thermal cycling (TC). Case II. Flex lid-induced failure. Case Ill. Hermeticity failures during TC. Case IV. Die metallization cracking during TC. and how many test cycles and parts is necessary? Case V. Wire Bond failures after life test. Case VI. Failures caused by Au/In IMC growth.
    Keywords: Electronics and Electrical Engineering
    Type: Components for Military and Space Electronics; Feb 11, 2008 - Feb 14, 2008; San Diego, California; United States
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  • 100
    Publication Date: 2019-07-13
    Description: Tantalum capacitors manufactured per military specifications are established reliability components and have less than 0.001% of failures per 1000 hours for grades D or S, thus positioning these parts among electronic components with the highest reliability characteristics. Still, failures of tantalum capacitors do happen and when it occurs it might have catastrophic consequences for the system. To reduce this risk, further development of a screening and qualification system with special attention to the possible deficiencies in the existing procedures is necessary. The purpose of this work is evaluation of the effect of surge current stress testing on reliability of the parts at both steady-state and multiple surge current stress conditions. In order to reveal possible degradation and precipitate more failures, various part types were tested and stressed in the range of voltage and temperature conditions exceeding the specified limits. A model to estimate the probability of post-surge current testing-screening failures and measures to improve the effectiveness of the screening process has been suggested.
    Keywords: Electronics and Electrical Engineering
    Type: Passive Components Symposium, CARTS; Mar 17, 2008 - Mar 20, 2008; Newport Beach,CA; United States
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