Science.gov

Sample records for acanthospermum hispidum dc

  1. Susceptibility of some vertebrate hosts to infection with early third-stage larvae of Gnathostoma hispidum.

    PubMed

    Sohn, W M; Lee, S H

    1997-09-01

    Susceptibility of some vertebrates was examined to the early third-stage larvae (EL3) of Gnathostoma hispidum. The larvae collected from the Chinese loaches were infected to 4 silk carps, 3 snake heads, 3 bullfrogs, 5 mice and 9 albino rats. No worms were detected in fish, silk carps and snake heads. In 3 bullfrogs fed 30 larvae, a total of 9 EL3 was recovered in the gastrointestinal tract (8 larvae) and liver (one). In 5 mice infected with 50 larvae, a total of 37 (74.0%) advanced third-stage larvae (AdL3) was recovered from the muscle (31 larvae), liver (5 larvae) and kidney at 4 weeks after infection. In 9 albino rats infected with 115 larvae, a total of 40 (34.8%) AdL3 was found in the muscle. The mammalian hosts were found susceptible to the EL3 of G. hispidum from Chinese loaches.

  2. The occurrence of Ophiocnemis marmorata (Echinodermata: Ophiuroidea) associated with the rhizostome medusa Rhopilema hispidum (Cnidaria: Scyphozoa)

    NASA Astrophysics Data System (ADS)

    Kanagaraj, Govindan; Kumar, Pithchai Sampath; Morandini, André C.

    2008-11-01

    The association of scyphomedusae with invertebrates has been long known in the literature; especially with hyperiids amphipods. The association of echinoderms with jellyfish is not common and rarely recorded. We reported the association of the ophiuroid Ophiocnemis marmorata with the rhizostome scyphomedusa Rhopilema hispidum collected in Vellar estuary (on the southeast coast of India). O. marmorata is supposed to be a filter feeding ophiuroid, quite common in soft bottom of shallow waters. The brittle stars possibly seek for food supply, shelter and protection through the association.

  3. Antifungal and proteolytic activities of endophytic fungi isolated from Piper hispidum Sw

    PubMed Central

    Orlandelli, Ravely Casarotti; de Almeida, Tiago Tognolli; Alberto, Raiani Nascimento; Polonio, Julio Cesar; Azevedo, João Lúcio; Pamphile, João Alencar

    2015-01-01

    Endophytes are being considered for use in biological control, and the enzymes they secrete might facilitate their initial colonization of internal plant tissues and direct interactions with microbial pathogens. Microbial proteases are also biotechnologically important products employed in bioremediation processes, cosmetics, and the pharmaceutical, photographic and food industries. In the present study, we evaluated antagonism and competitive interactions between 98 fungal endophytes and Alternaria alternata, Colletotrichum sp., Phyllosticta citricarpa and Moniliophthora perniciosa. We also examined the proteolytic activities of endophytes grown in liquid medium and conducted cup plate assays. The results showed that certain strains in the assemblage of P. hispidum endophytes are important sources of antifungal properties, primarily Lasiodiplodia theobromae JF766989, which reduced phytopathogen growth by approximately 54 to 65%. We detected 28 endophytes producing enzymatic halos of up to 16.40 mm in diameter. The results obtained in the present study highlight the proteolytic activity of the endophytes Phoma herbarum JF766995 and Schizophyllum commune JF766994, which presented the highest enzymatic halo diameters under at least one culture condition tested. The increased activities of certain isolates in the presence of rice or soy flour as a substrate (with halos up to 17.67 mm in diameter) suggests that these endophytes have the potential to produce enzymes using agricultural wastes. PMID:26273250

  4. Antifungal and proteolytic activities of endophytic fungi isolated from Piper hispidum Sw.

    PubMed

    Orlandelli, Ravely Casarotti; de Almeida, Tiago Tognolli; Alberto, Raiani Nascimento; Polonio, Julio Cesar; Azevedo, João Lúcio; Pamphile, João Alencar

    2015-06-01

    Endophytes are being considered for use in biological control, and the enzymes they secrete might facilitate their initial colonization of internal plant tissues and direct interactions with microbial pathogens. Microbial proteases are also biotechnologically important products employed in bioremediation processes, cosmetics, and the pharmaceutical, photographic and food industries. In the present study, we evaluated antagonism and competitive interactions between 98 fungal endophytes and Alternaria alternata, Colletotrichum sp., Phyllosticta citricarpa and Moniliophthora perniciosa. We also examined the proteolytic activities of endophytes grown in liquid medium and conducted cup plate assays. The results showed that certain strains in the assemblage of P. hispidum endophytes are important sources of antifungal properties, primarily Lasiodiplodia theobromae JF766989, which reduced phytopathogen growth by approximately 54 to 65%. We detected 28 endophytes producing enzymatic halos of up to 16.40 mm in diameter. The results obtained in the present study highlight the proteolytic activity of the endophytes Phoma herbarum JF766995 and Schizophyllum commune JF766994, which presented the highest enzymatic halo diameters under at least one culture condition tested. The increased activities of certain isolates in the presence of rice or soy flour as a substrate (with halos up to 17.67 mm in diameter) suggests that these endophytes have the potential to produce enzymes using agricultural wastes.

  5. Bidirectional DC/DC Converter

    NASA Astrophysics Data System (ADS)

    Pedersen, F.

    2008-09-01

    The presented bidirectional DC/DC converter design concept is a further development of an already existing converter used for low battery voltage operation.For low battery voltage operation a high efficient low parts count DC/DC converter was developed, and used in a satellite for the battery charge and battery discharge function.The converter consists in a bidirectional, non regulating DC/DC converter connected to a discharge regulating Buck converter and a charge regulating Buck converter.The Bidirectional non regulating DC/DC converter performs with relatively high efficiency even at relatively high currents, which here means up to 35Amps.This performance was obtained through the use of power MOSFET's with on- resistances of only a few mille Ohms connected to a special transformer allowing paralleling several transistor stages on the low voltage side of the transformer. The design is patent protected. Synchronous rectification leads to high efficiency at the low battery voltages considered, which was in the range 2,7- 4,3 Volt DC.The converter performs with low switching losses as zero voltage zero current switching is implemented in all switching positions of the converter.Now, the drive power needed, to switch a relatively large number of low Ohm , hence high drive capacitance, power MOSFET's using conventional drive techniques would limit the overall conversion efficiency.Therefore a resonant drive consuming considerable less power than a conventional drive circuit was implemented in the converter.To the originally built and patent protected bidirectional non regulating DC/DC converter, is added the functionality of regulation.Hereby the need for additional converter stages in form of a Charge Buck regulator and a Discharge Buck regulator is eliminated.The bidirectional DC/DC converter can be used in connection with batteries, motors, etc, where the bidirectional feature, simple design and high performance may be useful.

  6. Milliwatt dc/dc Inverter

    NASA Technical Reports Server (NTRS)

    Mclyman, C. W.

    1983-01-01

    Compact dc/dc inverter uses single integrated-circuit package containing six inverter gates that generate and amplify 100-kHz square-wave switching signal. Square-wave switching inverts 10-volt local power to isolated voltage at another desired level. Relatively high operating frequency reduces size of filter capacitors required, resulting in small package unit.

  7. A new species of Paramacrochiron (Copepoda: Cyclopoida: Macrochironidae) associated with the rhizostome medusa Rhopilema hispidum collected from the Gulf of Thailand, with a phylogenetic analysis of the family Macrochironidae.

    PubMed

    Ohtsuka, Susumu; Boxshall, Geoffrey A; Srinui, Khwanruan

    2012-02-01

    Paramacrochiron thailandicum n. sp. (Copepoda: Cyclopoida: Macrochironidae) is described from the rhizostome medusa Rhopilema hispidum occurring in the Gulf of Thailand. The new species is distinguishable from other congeners mainly by detailed features of the fourth legs and the urosome in both sexes. Copepodid and adult stages of the genus Paramacrochiron seem to be host-specific to rhizostome medusae, but may spend periods free in the plankton or benthos during the absence of the host. A cladistic analysis shows that the Macrochironidae comprises two main lineages. Paramacrochiron is recovered as a monophyletic group, located on one lineage together with Pseudomacrochiron, which appears as a paraphyletic taxon with the limited character set used. The other main lineage comprises the genera Macrochiron and Sewellochiron, but the sole species of the latter genus, Sewellochiron fidens, is nested within Macrochiron. This analysis provides little support for maintaining Sewellochiron as a separate genus.

  8. Adaptable DC offset correction

    NASA Technical Reports Server (NTRS)

    Golusky, John M. (Inventor); Muldoon, Kelly P. (Inventor)

    2009-01-01

    Methods and systems for adaptable DC offset correction are provided. An exemplary adaptable DC offset correction system evaluates an incoming baseband signal to determine an appropriate DC offset removal scheme; removes a DC offset from the incoming baseband signal based on the appropriate DC offset scheme in response to the evaluated incoming baseband signal; and outputs a reduced DC baseband signal in response to the DC offset removed from the incoming baseband signal.

  9. Thioprofundum hispidum sp. nov., an obligately chemolithoautotrophic sulfur-oxidizing gammaproteobacterium isolated from the hydrothermal field on Suiyo Seamount, and proposal of Thioalkalispiraceae fam. nov. in the order Chromatiales.

    PubMed

    Mori, Koji; Suzuki, Ken-ichiro; Urabe, Tetsuro; Sugihara, Maki; Tanaka, Kenji; Hamada, Moriyuki; Hanada, Satoshi

    2011-10-01

    A novel mesophilic, facultatively anaerobic, sulfur-oxidizing bacterial strain, designated gps61(T), was isolated from a surface rock sample collected from the hydrothermal field of Suiyo Seamount on the Izu-Bonin Arc in the Western Pacific Ocean. Cells of the isolate were rod-shaped with a single sheathed polar flagellum. Neither extensive internal membranes nor storage materials were present in the cells. In a 20 % CO(2) atmosphere, strain gps61(T) grew using thiosulfate, sulfur or tetrathionate as electron donors and oxygen or nitrate as electron acceptors. Other substrates, including organic acids and sugars, did not support growth, indicating that strain gps61(T) was an obligate chemolithoautotroph. 16S rRNA gene sequence analysis revealed that strain gps61(T) was closely related to Thioprofundum lithotrophicum 106(T) (98.5 % sequence similarity) in the order Chromatiales. Phylogenetic trees grouped strain gps61(T) and Thioprofundum lithotrophicum in the same cluster along with Thioalkalispira microaerophila and Thiohalophilus thiocyanoxidans, but it was apparent from the analysis that the novel strain had definitely departed from the family lineage. On the basis of its phylogenetic position along with its morphological and physiological characteristics, strain gps61(T) ( = NBRC 101261(T)  = DSM 18546(T)) represents a novel species of the genus Thioprofundum, for which the name Thioprofundum hispidum sp. nov. is proposed. In addition, we propose a novel family name, Thioalkalispiraceae, in the order Chromatiales, to accommodate the genera Thioalkalispira, Thiohalophilus and Thioprofundum.

  10. Efficient dc-to-dc converter

    NASA Technical Reports Server (NTRS)

    Black, J. M.

    1978-01-01

    Circuit consists of chopper section which converts input dc to square wave, followed by bridge-rectifier stage. Chopper gives nearly-ideal switching characteristics, and bridge uses series of full-wave stages rather than less-efficient half-wave rectifiers found in previous circuits. Special features of full-wave circuit allow redundant components to be eliminated, lowering parts count. Circuit can also be adapted for use as dc-to-dc converter or as combination dc-and-ac source.

  11. DC/DC Converter Stability Testing Study

    NASA Technical Reports Server (NTRS)

    Wang, Bright L.

    2008-01-01

    This report presents study results on hybrid DC/DC converter stability testing methods. An input impedance measurement method and a gain/phase margin measurement method were evaluated to be effective to determine front-end oscillation and feedback loop oscillation. In particular, certain channel power levels of converter input noises have been found to have high degree correlation with the gain/phase margins. It becomes a potential new method to evaluate stability levels of all type of DC/DC converters by utilizing the spectral analysis on converter input noises.

  12. Ethnobotanical Study of Medicinal Plants Used for the Treatment of Malaria in the Plateau Region, Togo

    PubMed Central

    Agbodeka, Kodjovi; Gbekley, Holaly E.; Karou, Simplice D.; Anani, Kokou; Agbonon, Amegnona; Tchacondo, Tchadjobo; Batawila, Komlan; Simpore, Jacques; Gbeassor, Messanvi

    2016-01-01

    Background: In Togo, malaria constitutes a major public health problem but, until now, the population still mostly relies on herbal medicine for healing. This study aimed to document medicinal plants used for malaria therapy in the Plateau region of the country. Methodology: Semi-structured questionnaire interviews were used to gather ethnobotanical and sociodemographic data from traditional healers of the study area. Results: A total of 61 plants species belonging to 33 families were found to be in use for malaria therapy in the Plateau region. Caesalpiniaceae were the most represented family with 7 species, followed by Euphorbiaceae and Poaceae with 4 species each. According to the relative frequency of citation (RFC), Newbouldia laevis Seem. (RFC =0.52), Sarcocephalus latifolius (Sm.) E.A. Bruce (RFC =0.48), Acanthospermum hispidum DC. (RFC =0.43), and Senna siamea (Lam.) H.S. Irwin and Barneby (RFC =0.40) were the most cited in the treatment of malaria in the traditional medicine in the Plateau region. The parts of plants used could either be the barks, roots, leaves, or whole plants. The recipes also could be a combination of various species of plants or plant parts. Conclusion: This study highlights the potential sources for the development of new antimalarial drugs from indigenous medicinal plants found in the Plateau region of Togo. Such results could be a starting point for in vitro antimalarial screenings. SUMMARY 61 plants species from 33 families are use for malaria therapy in the Plateau region of TogoThe main families are Caesalpiniaceae Euphorbiaceae and PoaceaeThe most used species are Newbouldia laevis Seem. (RFC = 0.52), Sarcocephalus latifolius (Sm.) E.A. Bruce (RFC = 0.48), Acanthospermum hispidum DC. (RFC = 0.43), and Senna siamea (Lam.) H.S. Irwin and Barneby (RFC = 0.40) Abbreviations Used: RFC: Relative frequency of citation, FC: Frequency of citation, Dec: Decoction, Orl: Oral route, Mac: Maceration, Jui: Juice, Inf: Infusion, Sau: Sauce

  13. DC source assemblies

    DOEpatents

    Campbell, Jeremy B; Newson, Steve

    2013-02-26

    Embodiments of DC source assemblies of power inverter systems of the type suitable for deployment in a vehicle having an electrically grounded chassis are provided. An embodiment of a DC source assembly comprises a housing, a DC source disposed within the housing, a first terminal, and a second terminal. The DC source also comprises a first capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the first terminal. The DC source assembly further comprises a second capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the second terminal.

  14. 76 FR 13926 - Airworthiness Directives; The Boeing Company Model DC-8-11, DC-8-12, DC-8-21, DC-8-31, DC-8-32...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-15

    ... Model DC-8-11, DC-8- 12, DC-8-21, DC-8-31, DC-8-32, DC-8-33, DC-8-41, DC-8-42, and DC-8-43 Airplanes; DC-8-50 Series Airplanes; DC-8F-54 and DC-8F-55 Airplanes; DC-8-60 Series Airplanes; DC-8-60F Series Airplanes; DC-8-70 Series Airplanes; and DC-8-70F Series Airplanes AGENCY:......

  15. 75 FR 61989 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-8-31, DC-8-32, DC-8-33, DC-8-41...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-07

    ... Corporation Model DC- 8-31, DC-8-32, DC-8-33, DC-8-41, DC-8-42, and DC-8-43 Airplanes; Model DC-8-50 Series Airplanes; Model DC-8F-54 and DC-8F-55 Airplanes; Model DC-8-60 Series Airplanes; Model DC-8-60F Series Airplanes; Model DC-8- 70 Series Airplanes; and Model DC-8-70F Series Airplanes AGENCY:......

  16. DC-to-DC switching converter

    NASA Technical Reports Server (NTRS)

    Cuk, Slobodan M. (Inventor); Middlebrook, Robert D. (Inventor)

    1980-01-01

    A dc-to-dc converter having nonpulsating input and output current uses two inductances, one in series with the input source, the other in series with the output load. An electrical energy transferring device with storage, namely storage capacitance, is used with suitable switching means between the inductances to DC level conversion. For isolation between the source and load, the capacitance may be divided into two capacitors coupled by a transformer, and for reducing ripple, the inductances may be coupled. With proper design of the coupling between the inductances, the current ripple can be reduced to zero at either the input or the output, or the reduction achievable in that way may be divided between the input and output.

  17. Multilevel DC link inverter

    DOEpatents

    Su, Gui-Jia

    2003-06-10

    A multilevel DC link inverter and method for improving torque response and current regulation in permanent magnet motors and switched reluctance motors having a low inductance includes a plurality of voltage controlled cells connected in series for applying a resulting dc voltage comprised of one or more incremental dc voltages. The cells are provided with switches for increasing the resulting applied dc voltage as speed and back EMF increase, while limiting the voltage that is applied to the commutation switches to perform PWM or dc voltage stepping functions, so as to limit current ripple in the stator windings below an acceptable level, typically 5%. Several embodiments are disclosed including inverters using IGBT's, inverters using thyristors. All of the inverters are operable in both motoring and regenerating modes.

  18. Radiation-Tolerant DC-DC Converters

    NASA Technical Reports Server (NTRS)

    Skutt, Glenn; Sable, Dan; Leslie, Leonard; Graham, Shawn

    2012-01-01

    A document discusses power converters suitable for space use that meet the DSCC MIL-PRF-38534 Appendix G radiation hardness level P classification. A method for qualifying commercially produced electronic parts for DC-DC converters per the Defense Supply Center Columbus (DSCC) radiation hardened assurance requirements was developed. Development and compliance testing of standard hybrid converters suitable for space use were completed for missions with total dose radiation requirements of up to 30 kRad. This innovation provides the same overall performance as standard hybrid converters, but includes assurance of radiation- tolerant design through components and design compliance testing. This availability of design-certified radiation-tolerant converters can significantly reduce total cost and delivery time for power converters for space applications that fit the appropriate DSCC classification (30 kRad).

  19. 75 FR 6160 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-15, DC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-08

    ... Douglas Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10... airworthiness directive (AD) for certain Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC- 10A and... would require a one-time installation of electrical bonding jumpers for the fill valve controllers...

  20. Forback DC-to-DC converter

    NASA Technical Reports Server (NTRS)

    Lukemire, Alan T. (Inventor)

    1993-01-01

    A pulse-width modulated DC-to-DC power converter including a first inductor, i.e. a transformer or an equivalent fixed inductor equal to the inductance of the secondary winding of the transformer, coupled across a source of DC input voltage via a transistor switch which is rendered alternately conductive (ON) and nonconductive (OFF) in accordance with a signal from a feedback control circuit is described. A first capacitor capacitively couples one side of the first inductor to a second inductor which is connected to a second capacitor which is coupled to the other side of the first inductor. A circuit load shunts the second capacitor. A semiconductor diode is additionally coupled from a common circuit connection between the first capacitor and the second inductor to the other side of the first inductor. A current sense transformer generating a current feedback signal for the switch control circuit is directly coupled in series with the other side of the first inductor so that the first capacitor, the second inductor and the current sense transformer are connected in series through the first inductor. The inductance values of the first and second inductors, moreover, are made identical. Such a converter topology results in a simultaneous voltsecond balance in the first inductance and ampere-second balance in the current sense transformer.

  1. Forback DC-to-DC converter

    NASA Technical Reports Server (NTRS)

    Lukemire, Alan T. (Inventor)

    1995-01-01

    A pulse-width modulated DC-to-DC power converter including a first inductor, i.e. a transformer or an equivalent fixed inductor equal to the inductance of the secondary winding of the transformer, coupled across a source of DC input voltage via a transistor switch which is rendered alternately conductive (ON) and nonconductive (OFF) in accordance with a signal from a feedback control circuit is described. A first capacitor capacitively couples one side of the first inductor to a second inductor which is connected to a second capacitor which is coupled to the other side of the first inductor. A circuit load shunts the second capacitor. A semiconductor diode is additionally coupled from a common circuit connection between the first capacitor and the second inductor to the other side of the first inductor. A current sense transformer generating a current feedback signal for the switch control circuit is directly coupled in series with the other side of the first inductor so that the first capacitor, the second inductor and the current sense transformer are connected in series through the first inductor. The inductance values of the first and second inductors, moreover, are made identical. Such a converter topology results in a simultaneous voltsecond balance in the first inductance and ampere-second balance in the current sense transformer.

  2. RISK D/C

    NASA Technical Reports Server (NTRS)

    Dias, W. C.

    1994-01-01

    RISK D/C is a prototype program which attempts to do program risk modeling for the Space Exploration Initiative (SEI) architectures proposed in the Synthesis Group Report. Risk assessment is made with respect to risk events, their probabilities, and the severities of potential results. The program allows risk mitigation strategies to be proposed for an exploration program architecture and to be ranked with respect to their effectiveness. RISK D/C allows for the fact that risk assessment in early planning phases is subjective. Although specific to the SEI in its present form, RISK D/C can be used as a framework for developing a risk assessment program for other specific uses. RISK D/C is organized into files, or stacks, of information, including the architecture, the hazard, and the risk event stacks. Although predefined, all stacks can be upgraded by a user. The architecture stack contains information concerning the general program alternatives, which are subsequently broken down into waypoints, missions, and mission phases. The hazard stack includes any background condition which could result in a risk event. A risk event is anything unfavorable that could happen during the course of a specific point within an architecture, and the risk event stack provides the probabilities, consequences, severities, and any mitigation strategies which could be used to reduce the risk of the event, and how much the risk is reduced. RISK D/C was developed for Macintosh series computers. It requires HyperCard 2.0 or later, as well as 2Mb of RAM and System 6.0.8 or later. A Macintosh II series computer is recommended due to speed concerns. The standard distribution medium for this package is one 3.5 inch 800K Macintosh format diskette. RISK D/C was developed in 1991 and is a copyrighted work with all copyright vested in NASA. Macintosh and HyperCard are trademarks of Apple Computer, Inc.

  3. 75 FR 23571 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-15, DC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-04

    ... Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F.... ACTION: Final rule. SUMMARY: We are adopting a new airworthiness directive (AD) for certain Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40,......

  4. DC Breakdown Experiments

    SciTech Connect

    Calatroni, S.; Descoeudres, A.; Levinsen, Y.; Taborelli, M.; Wuensch, W.

    2009-01-22

    In the context of the CLIC (Compact Linear Collider) project investigations of DC breakdown in ultra high vacuum are carried out in parallel with high power RF tests. From the point of view of saturation breakdown field the best material tested so far is stainless steel, followed by titanium. Copper shows a four times weaker breakdown field than stainless steel. The results indicate clearly that the breakdown events are initiated by field emission current and that the breakdown field is limited by the cathode. In analogy to RF, the breakdown probability has been measured in DC and the data show similar behaviour as a function of electric field.

  5. DC attenuation meter

    DOEpatents

    Hargrove, Douglas L.

    2004-09-14

    A portable, hand-held meter used to measure direct current (DC) attenuation in low impedance electrical signal cables and signal attenuators. A DC voltage is applied to the signal input of the cable and feedback to the control circuit through the signal cable and attenuators. The control circuit adjusts the applied voltage to the cable until the feedback voltage equals the reference voltage. The "units" of applied voltage required at the cable input is the system attenuation value of the cable and attenuators, which makes this meter unique. The meter may be used to calibrate data signal cables, attenuators, and cable-attenuator assemblies.

  6. DYLOS DC110

    EPA Science Inventory

    The Dylos DC1100 air quality monitor measures particulate matter (PM) to provide a continuous assessment of indoor air quality. The unit counts particles in two size ranges: large and small. According to the manufacturer, large particles have diameters between 2.5 and 10 micromet...

  7. DC arc weld starter

    DOEpatents

    Campiotti, Richard H.; Hopwood, James E.

    1990-01-01

    A system for starting an arc for welding uses three DC power supplies, a high voltage supply for initiating the arc, an intermediate voltage supply for sustaining the arc, and a low voltage welding supply directly connected across the gap after the high voltage supply is disconnected.

  8. Early Oscillation Detection for DC/DC Converter Fault Diagnosis

    NASA Technical Reports Server (NTRS)

    Wang, Bright L.

    2011-01-01

    The electrical power system of a spacecraft plays a very critical role for space mission success. Such a modern power system may contain numerous hybrid DC/DC converters both inside the power system electronics (PSE) units and onboard most of the flight electronics modules. One of the faulty conditions for DC/DC converter that poses serious threats to mission safety is the random occurrence of oscillation related to inherent instability characteristics of the DC/DC converters and design deficiency of the power systems. To ensure the highest reliability of the power system, oscillations in any form shall be promptly detected during part level testing, system integration tests, flight health monitoring, and on-board fault diagnosis. The popular gain/phase margin analysis method is capable of predicting stability levels of DC/DC converters, but it is limited only to verification of designs and to part-level testing on some of the models. This method has to inject noise signals into the control loop circuitry as required, thus, interrupts the DC/DC converter's normal operation and increases risks of degrading and damaging the flight unit. A novel technique to detect oscillations at early stage for flight hybrid DC/DC converters was developed.

  9. AC/DC converter

    NASA Astrophysics Data System (ADS)

    Jain, Praveen K.

    1992-08-01

    In a system such as a 20 kHz space station primary electrical power distribution system, power conversion from AC to DC is required. Some of the basic requirements for this conversion are high efficiency, light weight and small volume, regulated output voltage, close to unity input power factor, distortionless input current, soft-starting, low electromagnetic interference, and high reliability. An AC-to-DC converter is disclosed which satisfies the main design objectives of such converters for use in space. The converter of the invention comprises an input transformer, a resonant network, a current controller, a diode rectifier, and an output filter. The input transformer is for connection to a single phase, high frequency, sinusoidal waveform AC voltage source and provides a matching voltage isolating from the AC source. The resonant network converts this voltage to a sinusoidal, high frequency bidirectional current output, which is received by the current controller to provide the desired output current. The diode rectifier is connected in parallel with the current controller to convert the bidirectional current into a unidirectional current output. The output filter is connected to the rectifier to provide an essentially ripple-free, substantially constant voltage DC output.

  10. 76 FR 18022 - Airworthiness Directives; The Boeing Company Model DC-9-14, DC-9-15, and DC-9-15F Airplanes; and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-01

    ... Model DC-9-14, DC-9- 15, and DC-9-15F Airplanes; and DC-9-20, DC-9-30, DC-9-40, and DC-9-50 Series..., Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590. FOR FURTHER INFORMATION CONTACT...) This AD applies to The Boeing Company Model DC-9-14, DC-9- 15, DC-9-15F, DC-9-21, DC-9-31,......

  11. 75 FR 47242 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-14, DC-9-15, and DC-9-15F...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-05

    ... Corporation Model DC- 9-14, DC-9-15, and DC-9-15F Airplanes; and Model DC-9-20, DC-9-30, DC- 9-40, and DC-9-50... airworthiness directive (AD) that applies to certain Model DC-9-14 and DC-9-15 airplanes; and Model DC-9-20, DC-9-30, DC-9-40, and DC-9-50 series airplanes. The existing AD currently......

  12. Isolated Bidirectional DC-DC Converter for Hybrid Electric Vehicle Application

    DTIC Science & Technology

    2006-06-13

    34Approved for public release: distribution is unlimited" Isolated Bidirectional DC-DC Converter for Hybrid Electric Vehicle Applications Sonya...requirements for DC-DC converters for electric and hybrid vehicles . This paper introduces a bidirectional, isolated DC-DC converter for medium power...the design and build of a medium power DC-DC converter . Key words: Power Converter , DC-DC, Hybrid Electric Vehicle , Battery, Galvanically Isolation

  13. Auxiliary resonant DC tank converter

    DOEpatents

    Peng, Fang Z.

    2000-01-01

    An auxiliary resonant dc tank (ARDCT) converter is provided for achieving soft-switching in a power converter. An ARDCT circuit is coupled directly across a dc bus to the inverter to generate a resonant dc bus voltage, including upper and lower resonant capacitors connected in series as a resonant leg, first and second dc tank capacitors connected in series as a tank leg, and an auxiliary resonant circuit comprising a series combination of a resonant inductor and a pair of auxiliary switching devices. The ARDCT circuit further includes first clamping means for holding the resonant dc bus voltage to the dc tank voltage of the tank leg, and second clamping means for clamping the resonant dc bus voltage to zero during a resonant period. The ARDCT circuit resonantly brings the dc bus voltage to zero in order to provide a zero-voltage switching opportunity for the inverter, then quickly rebounds the dc bus voltage back to the dc tank voltage after the inverter changes state. The auxiliary switching devices are turned on and off under zero-current conditions. The ARDCT circuit only absorbs ripples of the inverter dc bus current, thus having less current stress. In addition, since the ARDCT circuit is coupled in parallel with the dc power supply and the inverter for merely assisting soft-switching of the inverter without participating in real dc power transmission and power conversion, malfunction and failure of the tank circuit will not affect the functional operation of the inverter; thus a highly reliable converter system is expected.

  14. DC Cable for Railway

    NASA Astrophysics Data System (ADS)

    Tomita, Masaru

    The development of a superconducting cable for railways has commenced, assuming that a DC transmission cable will be used for electric trains. The cable has been fabricated based on the results of current testing of a superconducting wire, and various evaluation tests have been performed to determine the characteristics of the cable. A superconducting transmission cable having zero electrical resistance and suitable for railway use is expected to enhance regeneration efficiency, reduce power losses, achieve load leveling and integration of sub-stations, and reduce rail potential.

  15. Analysis of self-oscillating dc-to-dc converters

    NASA Technical Reports Server (NTRS)

    Burger, P.

    1974-01-01

    The basic operational characteristics of dc-to-dc converters are analyzed along with the basic physical characteristics of power converters. A simple class of dc-to-dc power converters are chosen which could satisfy any set of operating requirements, and three different controlling methods in this class are described in detail. Necessary conditions for the stability of these converters are measured through analog computer simulation whose curves are related to other operational characteristics, such as ripple and regulation. Further research is suggested for the solution of absolute stability and efficient physical design of this class of power converters.

  16. Multiple high voltage output DC-to-DC power converter

    NASA Technical Reports Server (NTRS)

    Cronin, Donald L. (Inventor); Farber, Bertrand F. (Inventor); Gehm, Hartmut K. (Inventor); Goldin, Daniel S. (Inventor)

    1977-01-01

    Disclosed is a multiple output DC-to-DC converter. The DC input power is filtered and passed through a chopper preregulator. The chopper output is then passed through a current source inverter controlled by a squarewave generator. The resultant AC is passed through the primary winding of a transformer, with high voltages induced in a plurality of secondary windings. The high voltage secondary outputs are each solid-state rectified for passage to individual output loads. Multiple feedback loops control the operation of the chopper preregulator, one being responsive to the current through the primary winding and another responsive to the DC voltage level at a selected output.

  17. Improved DC Gun Insulator

    SciTech Connect

    M.L. Neubauer, K.B. Beard, R. Sah, C. Hernandez-Garcia, G. Neil

    2009-05-01

    Many user facilities such as synchrotron light sources and free electron lasers require accelerating structures that support electric fields of 10-100 MV/m, especially at the start of the accelerator chain where ceramic insulators are used for very high gradient DC guns. These insulators are difficult to manufacture, require long commissioning times, and have poor reliability, in part because energetic electrons bury themselves in the ceramic, creating a buildup of charge and causing eventual puncture. A novel ceramic manufacturing process is proposed. It will incorporate bulk resistivity in the region where it is needed to bleed off accumulated charge caused by highly energetic electrons. This process will be optimized to provide an appropriate gradient in bulk resistivity from the vacuum side to the air side of the HV standoff ceramic cylinder. A computer model will be used to determine the optimum cylinder dimensions and required resistivity gradient for an example RF gun application. A ceramic material example with resistivity gradient appropriate for use as a DC gun insulator will be fabricated by glazing using doping compounds and tested.

  18. SCM Handbooks for dc-to-dc Converters

    NASA Technical Reports Server (NTRS)

    Lee, F.; Mohmoud, M.; Yu, Y.

    1984-01-01

    Two documents aid in design of control modules for dc-to-dc converters. Features of SCM include: Adaptive stability, power component stress limiting, implementation of various control laws, unified design approach. Analysis and quidelines contained in handbooks enable engineer to design SCM circuit and confidently predict resulting overall performance.

  19. Efficient Design in a DC to DC Converter Unit

    NASA Technical Reports Server (NTRS)

    Bruemmer, Joel E.; Williams, Fitch R.; Schmitz, Gregory V.

    2002-01-01

    Space Flight hardware requires high power conversion efficiencies due to limited power availability and weight penalties of cooling systems. The International Space Station (ISS) Electric Power System (EPS) DC-DC Converter Unit (DDCU) power converter is no exception. This paper explores the design methods and tradeoffs that were utilized to accomplish high efficiency in the DDCU. An isolating DC to DC converter was selected for the ISS power system because of requirements for separate primary and secondary grounds and for a well-regulated secondary output voltage derived from a widely varying input voltage. A flyback-current-fed push-pull topology or improved Weinberg circuit was chosen for this converter because of its potential for high efficiency and reliability. To enhance efficiency, a non-dissipative snubber circuit for the very-low-Rds-on Field Effect Transistors (FETs) was utilized, redistributing the energy that could be wasted during the switching cycle of the power FETs. A unique, low-impedance connection system was utilized to improve contact resistance over a bolted connection. For improved consistency in performance and to lower internal wiring inductance and losses a planar bus system is employed. All of these choices contributed to the design of a 6.25 KW regulated dc to dc converter that is 95 percent efficient. The methodology used in the design of this DC to DC Converter Unit may be directly applicable to other systems that require a conservative approach to efficient power conversion and distribution.

  20. Dc-To-Dc Converter Uses Reverse Conduction Of MOSFET's

    NASA Technical Reports Server (NTRS)

    Gruber, Robert P.; Gott, Robert W.

    1991-01-01

    In modified high-power, phase-controlled, full-bridge, pulse-width-modulated dc-to-dc converters, switching devices power metal oxide/semiconductor field-effect transistors (MOSFET's). Decreases dissipation of power during switching by eliminating approximately 0.7-V forward voltage drop in anti-parallel diodes. Energy-conversion efficiency increased.

  1. First experimental results from DC/DC and AC/DC plasma-based power transformers

    NASA Astrophysics Data System (ADS)

    McEvoy, Aaron; Gibson, William; Nebel, Richard

    2016-10-01

    A plasma-based power transformer has been built and operated in both DC/DC and AC/DC mode. The proprietary Tibbar Plasma Technologies, Inc. transformer design consists of two cylindrically symmetric helical primary electrodes surrounding a low temperature plasma within which a secondary axial current is generated. Initial experimental results have compared well with simulations and moderate conversion efficiencies have been observed. A new proprietary device is currently being constructed that will utilize 3-phase 480 VAC input to achieve higher conversion efficiency and output power. A description of the apparatus and several potential applications will be presented along with preliminary experimental data demonstrating the DC/DC and AC/DC conversion processes. Work performed under ARPA-E contract DE-AR0000677.

  2. Early Oscillation Detection Technique for Hybrid DC/DC Converters

    NASA Technical Reports Server (NTRS)

    Wang, Bright L.

    2011-01-01

    Oscillation or instability is a situation that must be avoided for reliable hybrid DC/DC converters. A real-time electronics measurement technique was developed to detect catastrophic oscillations at early stages for hybrid DC/DC converters. It is capable of identifying low-level oscillation and determining the degree of the oscillation at a unique frequency for every individual model of the converters without disturbing their normal operations. This technique is specially developed for space-used hybrid DC/DC converters, but it is also suitable for most of commercial and military switching-mode power supplies. This is a weak-electronic-signal detection technique to detect hybrid DC/DC converter oscillation presented as a specific noise signal at power input pins. It is based on principles of feedback control loop oscillation and RF signal modulations, and is realized by using signal power spectral analysis. On the power spectrum, a channel power amplitude at characteristic frequency (CPcf) and a channel power amplitude at switching frequency (CPsw) are chosen as oscillation level indicators. If the converter is stable, the CPcf is a very small pulse and the CPsw is a larger, clear, single pulse. At early stage of oscillation, the CPcf increases to a certain level and the CPsw shows a small pair of sideband pulses around it. If the converter oscillates, the CPcf reaches to a higher level and the CPsw shows more high-level sideband pulses. A comprehensive stability index (CSI) is adopted as a quantitative measure to accurately assign a degree of stability to a specific DC/DC converter. The CSI is a ratio of normal and abnormal power spectral density, and can be calculated using specified and measured CPcf and CPsw data. The novel and unique feature of this technique is the use of power channel amplitudes at characteristic frequency and switching frequency to evaluate stability and identify oscillations at an early stage without interfering with a DC/DC converter s

  3. A DC Transformer

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C.; Ihlefeld, Curtis M.; Starr, Stanley O.

    2013-01-01

    A component level dc transformer is described in which no alternating currents or voltages are present. It operates by combining features of a homopolar motor and a homopolar generator, both de devices, such that the output voltage of a de power supply can be stepped up (or down) with a corresponding step down (or up) in current. The basic theory for this device is developed, performance predictions are made, and the results from a small prototype are presented. Based on demonstrated technology in the literature, this de transformer should be scalable to low megawatt levels, but it is more suited to high current than high voltage applications. Significant development would be required before it could achieve the kilovolt levels needed for de power transmission.

  4. Triple voltage dc-to-dc converter and method

    DOEpatents

    Su, Gui-Jia

    2008-08-05

    A circuit and method of providing three dc voltage buses and transforming power between a low voltage dc converter and a high voltage dc converter, by coupling a primary dc power circuit and a secondary dc power circuit through an isolation transformer; providing the gating signals to power semiconductor switches in the primary and secondary circuits to control power flow between the primary and secondary circuits and by controlling a phase shift between the primary voltage and the secondary voltage. The primary dc power circuit and the secondary dc power circuit each further comprising at least two tank capacitances arranged in series as a tank leg, at least two resonant switching devices arranged in series with each other and arranged in parallel with the tank leg, and at least one voltage source arranged in parallel with the tank leg and the resonant switching devices, said resonant switching devices including power semiconductor switches that are operated by gating signals. Additional embodiments having a center-tapped battery on the low voltage side and a plurality of modules on both the low voltage side and the high voltage side are also disclosed for the purpose of reducing ripple current and for reducing the size of the components.

  5. Bi-Directional DC-DC Converter for PHEV Applications

    SciTech Connect

    Abas Goodarzi

    2011-01-31

    Plug-In Hybrid Electric Vehicles (PHEV) require high power density energy storage system (ESS) for hybrid operation and high energy density ESS for Electric Vehicle (EV) mode range. However, ESS technologies to maximize power density and energy density simultaneously are not commercially feasible. The use of bi-directional DC-DC converter allows use of multiple energy storage, and the flexible DC-link voltages can enhance the system efficiency and reduce component sizing. This will improve fuel consumption, increase the EV mode range, reduce the total weight, reduce battery initial and life cycle cost, and provide flexibility in system design.

  6. GaN Microwave DC-DC Converters

    NASA Astrophysics Data System (ADS)

    Ramos Franco, Ignacio

    Increasing the operating frequency of switching converters can have a direct impact in the miniaturization and integration of power converters. The size of energy-storage passive components and the difficulty to integrate them with the rest of the circuitry is a major challenge in the development of a fully integrated power supply on a chip. The work presented in this thesis attempts to address some of the difficulties encountered in the design of high-frequency converters by applying concepts and techniques usually used in the design of high-efficiency power amplifiers and high-efficiency rectifiers at microwave frequencies. The main focus is in the analysis, design, and characterization of dc-dc converters operating at microwave frequencies in the low gigahertz range. The concept of PA-rectifier duality, where a high-efficiency power amplifier operates as a high-efficiency rectifier is investigated through non-linear simulations and experimentally validated. Additionally, the concept of a self-synchronous rectifier, where a transistor rectifier operates synchronously without the need of a RF source or driver is demonstrated. A theoretical analysis of a class-E self-synchronous rectifier is presented and validated through non-linear simulations and experiments. Two GaN class-E2 dc-dc converters operating at a switching frequency of 1 and 1.2 GHz are demonstrated. The converters achieve 80 % and 75 % dc-dc efficiency respectively and are among the highest-frequency and highest-efficiency reported in the literature. The application of the concepts established in the analysis of a self-synchronous rectifier to a power amplifier culminated in the development of an oscillating, self-synchronous class-E 2 dc-dc converter. Finally, a proof-of-concept fully integrated GaN MMIC class-E 2 dc-dc converter switching at 4.6 GHz is demonstrated for the first time to the best of our knowledge. The 3.8 mm x 2.6 mm chip contains distributed inductors and does not require any

  7. Piezometer completion report for borehold cluster sites DC-19, DC-20 and DC-22

    SciTech Connect

    Jackson, R.L.; Diediker, L.D.; Ledgerwood, R.K.; Veatch, M.D.

    1984-07-01

    This report describes the design and installation of multi-level piezometers at borehole cluster sites DC-19, DC-20 and DC-22. The network of borehole cluster sites will provide facilities for multi-level water-level monitoring across the RRL for piezometer baseline monitoring and for large-scale hydraulic stress testing. These groundwater-monitoring facilities were installed between August 1983 and March 1984. Three series of piezometer nests (A-, C- and D-series) were installed in nine hydrogeologic units (monitoring horizons) within the Columbia River Basalt Group at each borehole cluster site. In addition to the piezometer facilities, a B-series pumping well was installed at borehole cluster sites DC-20 and DC-22. The A-series piezometer nest monitors the basal Ringold sediments and the Rattlesnake Ridge interbed. The C-series piezometer nests monitors the six deepest horizons, which are in increasing depth, the Priest Rapids interflow. 21 refs., 6 figs., 14 tabs.

  8. DC-Compensated Current Transformer.

    PubMed

    Ripka, Pavel; Draxler, Karel; Styblíková, Renata

    2016-01-20

    Instrument current transformers (CTs) measure AC currents. The DC component in the measured current can saturate the transformer and cause gross error. We use fluxgate detection and digital feedback compensation of the DC flux to suppress the overall error to 0.15%. This concept can be used not only for high-end CTs with a nanocrystalline core, but it also works for low-cost CTs with FeSi cores. The method described here allows simultaneous measurements of the DC current component.

  9. Digital Control Technologies for Modular DC-DC Converters

    NASA Technical Reports Server (NTRS)

    Button, Robert M.; Kascak, Peter E.; Lebron-Velilla, Ramon

    2002-01-01

    Recent trends in aerospace Power Management and Distribution (PMAD) systems focus on using commercial off-the-shelf (COTS) components as standard building blocks. This move to more modular designs has been driven by a desire to reduce costs and development times, but is also due to the impressive power density and efficiency numbers achieved by today's commercial DC-DC converters. However, the PMAD designer quickly learns of the hidden "costs" of using COTS converters. The most significant cost is the required addition of external input filters to meet strict electromagnetic interference (MIAMI) requirements for space systems. In fact, the high power density numbers achieved by the commercial manufacturers are greatly due to the lack of necessary input filters included in the COTS module. The NASA Glenn Research Center is currently pursuing a digital control technology that addresses this problem with modular DC-DC converters. This paper presents the digital control technologies that have been developed to greatly reduce the input filter requirements for paralleled, modular DC-DC converters. Initial test result show that the input filter's inductor size was reduced by 75 percent, and the capacitor size was reduced by 94 percent while maintaining the same power quality specifications.

  10. Greening America's Capitals - Washington, DC

    EPA Pesticide Factsheets

    This Greening America's Capitals report describes design options for the Anacostia Metro station in Washington, DC, that could help people feel safer and more comfortable walking to and from the station.

  11. 76 FR 68745 - DC Energy, LLC; DC Energy Mid-Atlantic, LLC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-07

    ... No: 2011-28690] DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. EL12-8-000] DC Energy, LLC; DC Energy Mid-Atlantic, LLC v. PJM Interconnection, L.L.C.; Notice of Complaint Take notice... Commission (Commission), 18 CFR 385.206 (2011), DC Energy, LLC (DC Energy) and DC Energy Mid-Atlantic...

  12. Commercial Of-The Shelf DC/DC Converter

    NASA Astrophysics Data System (ADS)

    Denzinger, W.; Baumel, S.

    2011-10-01

    A commercial of-the-shelf (COTS) DC/DC converter for the supply of digital electronics on board of spacecraft has been developed with special emphasis on: *Low cost Readily available *Easy manufacturing *No use of ITAR listed EEE parts like rad-hard mosfets *Minimum number of rad-hard digital and analog IC's *Design tolerance against SEE by appropriate filtering The study was supported by the European Space Agency (ESA) under the contract number 21729/08/NL7LvH.

  13. Light-weight DC to very high voltage DC converter

    DOEpatents

    Druce, R.L.; Kirbie, H.C.; Newton, M.A.

    1998-06-30

    A DC-DC converter capable of generating outputs of 100 KV without a transformer comprises a silicon opening switch (SOS) diode connected to allow a charging current from a capacitor to flow into an inductor. When a specified amount of charge has flowed through the SOS diode, it opens up abruptly; and the consequential collapsing field of the inductor causes a voltage and current reversal that is steered into a load capacitor by an output diode. A switch across the series combination of the capacitor, inductor, and SOS diode closes to periodically reset the SOS diode by inducing a forward-biased current. 1 fig.

  14. Light-weight DC to very high voltage DC converter

    DOEpatents

    Druce, Robert L.; Kirbie, Hugh C.; Newton, Mark A.

    1998-01-01

    A DC-DC converter capable of generating outputs of 100 KV without a transformer comprises a silicon opening switch (SOS) diode connected to allow a charging current from a capacitor to flow into an inductor. When a specified amount of charge has flowed through the SOS diode, it opens up abruptly; and the consequential collapsing field of the inductor causes a voltage and current reversal that is steered into a load capacitor by an output diode. A switch across the series combination of the capacitor, inductor, and SOS diode closes to periodically reset the SOS diode by inducing a forward-biased current.

  15. Switching coordination of distributed dc-dc converters for highly efficient photovoltaic power plants

    SciTech Connect

    Agamy, Mohammed; Elasser, Ahmed; Sabate, Juan Antonio; Galbraith, Anthony William; Harfman Todorovic, Maja

    2014-09-09

    A distributed photovoltaic (PV) power plant includes a plurality of distributed dc-dc converters. The dc-dc converters are configured to switch in coordination with one another such that at least one dc-dc converter transfers power to a common dc-bus based upon the total system power available from one or more corresponding strings of PV modules. Due to the coordinated switching of the dc-dc converters, each dc-dc converter transferring power to the common dc-bus continues to operate within its optimal efficiency range as well as to optimize the maximum power point tracking in order to increase the energy yield of the PV power plant.

  16. Piezometer completion report for borehole cluster sites DC-19, DC-20, and DC-22

    SciTech Connect

    Jackson, R.L.; Diediker, L.D.; Ledgerwood, R.K.; Veatch, M.D.

    1984-07-01

    This report describes the design and installation of multi-level piezometers at borehole cluster sites DC-19, DC-20 and DC-22. The network of borehole cluster sites will provide facilities for multi-level water-level monitoring across the RRL for piezometer baseline monitoring and for large-scale hydraulic stress testing. These groundwater-monitoring facilities were installed between August 1983 and March 1984. Three series of piezometer nests (A-, C- and D-series) were installed in nine hydrogeologic units (monitoring horizons) within the Columbia River Basalt Group at each borehole cluster site. In addition to the piezometer facilities, a B-series pumping well was installed at borehole cluster sites DC-20 and DC-22. The A-series piezometer nest monitors the basal Ringold sediments and the Rattlesnake Ridge interbed. The C-series piezometer nests monitors the six deepest horizons, which are in increasing depth, the Priest Rapids interflow, Sentinel Gap flow top, Ginkgo flow top, Rocky Coulee flow top, Cohassett flow top and Umtanum flow top. The D-series piezometer monitors the Mabton interbed. The B-series pumping well was completed in the Priest Rapids interflow. 21 refs., 6 figs., 6 tabs.

  17. Soft switching active snubbers for DC/DC converters

    SciTech Connect

    Elasser, A.; Torrey, D.A.

    1996-09-01

    A soft-switching active snubber is proposed to reduce the turn-off losses of the insulated gate bipolar transistor (IGBT) in a buck converter. The soft-switching snubber provides zero-voltage switching for the IGBT, thereby reducing its high turn-off losses due to the current tailing. The proposed snubber uses an auxiliary switch to discharge the snubber capacitor. This auxiliary switch also operates at zero-voltage and zero-current switching. The size of the auxiliary switch compared to the main switch makes this snubber a good alternative to the conventional snubber or even to passive low-loss snubbers. The use of the soft-switching active snubber permits the IGBT to operate at high frequencies with an improved RBSOA. In the experimental results reported for a 1 kW, 40 kHz prototype, combined switching/snubbing losses are reduced by 36% through the use of the active snubber compared to a conventional RCD snubber. The use of an active snubber capacitor during turn-off. The generic snubber cell for the buck converter is generalized to support the common nonisolated dc/dc converters (buck, boost, buck-boost, Cuk, sepic, zeta) as well as isolated dc/dc converters (forward, flyback, Cuk, and sepic).

  18. DC coupled Doppler radar physiological monitor.

    PubMed

    Zhao, Xi; Song, Chenyan; Lubecke, Victor; Boric-Lubecke, Olga

    2011-01-01

    One of the challenges in Doppler radar systems for physiological monitoring is a large DC offset in baseband outputs. Typically, AC coupling is used to eliminate this DC offset. Since the physiological signals of interest include frequency content near DC, it is not desirable to simply use AC coupling on the radar outputs. While AC coupling effectively removes DC offset, it also introduces a large time delay and distortion. This paper presents the first DC coupled IQ demodulator printed circuit board (PCB) design and measurements. The DC coupling is achieved by using a mixer with high LO to RF port isolation, resulting in a very low radar DC offset on the order of mV. The DC coupled signals from the PCB radar system were successfully detected with significant LNA gain without saturation. Compared to the AC coupled results, the DC coupled results show great advantages of less signal distortion and more accurate rate estimation.

  19. DC-Powered Jumping Ring

    ERIC Educational Resources Information Center

    Jeffery, Rondo N.; Farhang, Amiri

    2016-01-01

    The classroom jumping ring demonstration is nearly always performed using alternating current (AC), in which the ring jumps or flies off the extended iron core when the switch is closed. The ring jumps higher when cooled with liquid nitrogen (LN2). We have performed experiments using DC to power the solenoid and find similarities and significant…

  20. Experiments with a DC Motor

    ERIC Educational Resources Information Center

    Kraftmakher, Yaakov

    2010-01-01

    Experiments with an electric motor provide good opportunity to demonstrate some basic laws of electricity and magnetism. The aim of the experiments with a low-power dc motor is to show how the motor approaches its steady rotation and how its torque, mechanical power and efficiency depend on the rotation velocity. The tight relationship between the…

  1. Compact integrated dc SQUID gradiometer

    SciTech Connect

    de Waal, V.J.; Klapwijk, T.M.

    1982-10-01

    An all-niobium integrated system of first-order gradiometer and dc suprconducting quantum interference device (SQUID) has been developed. It is relatively simple to fabricate, has an overall size of 17 x 12 mm and a sensitivity of 3.5 x 10/sup -12/ T m/sup -1/ Hz/sup -1/2/.

  2. Designing dc Inductors With Airgaps

    NASA Technical Reports Server (NTRS)

    Wagner, A. P.

    1986-01-01

    Optimal parameters obtained designing near saturation point. New iterative procedure aids design of dc inductors with airgaps in cores. For given core area and length, technique gives design having specified inductance and peak flux density in core, using minimum required copper weight. Executed rapidly on programmable, hand-held calculator. Applications include lightweight inductors for aircraft electronics.

  3. 76 FR 53346 - Airworthiness Directives; The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-26

    ... Model DC-9-81 (MD- 81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 Airplanes AGENCY... Jersey Avenue, SE., Washington, DC 20590. Hand Delivery: Deliver to Mail address above between 9 a.m. and...) This AD applies to The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83),...

  4. 75 FR 68686 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-14, DC-9-15, and DC-9-15F...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-09

    ...; AD 2010-23-10] RIN 2120-AA64 Airworthiness Directives; McDonnell Douglas Corporation Model DC- 9-14, DC-9-15, and DC-9-15F Airplanes; and Model DC-9-20, DC-9-30, DC- 9-40, and DC-9-50 Series Airplanes... Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590. FOR FURTHER...

  5. 75 FR 62331 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-14, DC-9-15, and DC-9-15F...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-08

    ... Directives; McDonnell Douglas Corporation Model DC- 9-14, DC-9-15, and DC-9-15F Airplanes; and DC-9-20, DC-9-30, DC-9-40, and DC-9-50 Series Airplanes AGENCY: Federal Aviation Administration (FAA), DOT. ACTION... Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590. Hand Delivery: Deliver to...

  6. 76 FR 1993 - Airworthiness Directives; The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-12

    ... Model DC-9-81 (MD- 81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 Airplanes AGENCY... Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590. FOR FURTHER INFORMATION.... Applicability (c) This AD applies to The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83...

  7. 76 FR 41651 - Airworthiness Directives; The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-15

    ... Model DC-9-81 (MD- 81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 Airplanes AGENCY... Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590. FOR FURTHER INFORMATION...) This AD applies to The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83),...

  8. 76 FR 39251 - Airworthiness Directives; The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-06

    ... Model DC-9-81 (MD- 81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 Airplanes AGENCY... Jersey Avenue, SE., Washington, DC 20590. FOR FURTHER INFORMATION CONTACT: Roger Durbin, Aerospace.... Applicability (c) This AD applies to all The Boeing Company Model DC-9-81 (MD- 81), DC-9-82 (MD-82), DC-9-83...

  9. Identification of cDC1- and cDC2-committed DC progenitors reveals early lineage priming at the common DC progenitor stage in the bone marrow.

    PubMed

    Schlitzer, Andreas; Sivakamasundari, V; Chen, Jinmiao; Sumatoh, Hermi Rizal Bin; Schreuder, Jaring; Lum, Josephine; Malleret, Benoit; Zhang, Sanqian; Larbi, Anis; Zolezzi, Francesca; Renia, Laurent; Poidinger, Michael; Naik, Shalin; Newell, Evan W; Robson, Paul; Ginhoux, Florent

    2015-07-01

    Mouse conventional dendritic cells (cDCs) can be classified into two functionally distinct lineages: the CD8α(+) (CD103(+)) cDC1 lineage, and the CD11b(+) cDC2 lineage. cDCs arise from a cascade of bone marrow (BM) DC-committed progenitor cells that include the common DC progenitors (CDPs) and pre-DCs, which exit the BM and seed peripheral tissues before differentiating locally into mature cDCs. Where and when commitment to the cDC1 or cDC2 lineage occurs remains poorly understood. Here we found that transcriptional signatures of the cDC1 and cDC2 lineages became evident at the single-cell level from the CDP stage. We also identified Siglec-H and Ly6C as lineage markers that distinguished pre-DC subpopulations committed to the cDC1 lineage (Siglec-H(-)Ly6C(-) pre-DCs) or cDC2 lineage (Siglec-H(-)Ly6C(+) pre-DCs). Our results indicate that commitment to the cDC1 or cDC2 lineage occurs in the BM and not in the periphery.

  10. DC to DC power converters and methods of controlling the same

    DOEpatents

    Steigerwald, Robert Louis; Elasser, Ahmed; Sabate, Juan Antonio; Todorovic, Maja Harfman; Agamy, Mohammed

    2012-12-11

    A power generation system configured to provide direct current (DC) power to a DC link is described. The system includes a first power generation unit configured to output DC power. The system also includes a first DC to DC converter comprising an input section and an output section. The output section of the first DC to DC converter is coupled in series with the first power generation unit. The first DC to DC converter is configured to process a first portion of the DC power output by the first power generation unit and to provide an unprocessed second portion of the DC power output of the first power generation unit to the output section.

  11. DC Water: 2009 Presidential Inauguration Supporting Documentation

    EPA Pesticide Factsheets

    DC Water located in Washington, DC incurred costs for activities related to the Presidential Inauguration in January 2009. Support included the purchase and installation of special manhole covers with security features.

  12. Combination of DC Vaccine and Conventional Chemotherapeutics.

    PubMed

    Dong, Wei; Wei, Ran; Shen, Hongchang; Ni, Yang; Meng, Long; Du, Jiajun

    2016-01-01

    Recently mutual interactions of chemotherapy and immunotherapy have been widely accepted, and several synergistic mechanisms have been elucidated as well. Although much attention has focused on the combination of DC vaccine and chemotherapy, there are still many problems remaining to be resolved, including the optimal treatment schedule of the novel strategy. In this article, we methodically examined literature about the combination strategy of DC vaccine and conventional chemotherapy. Based on the published preclinical and clinical trials, treatment schedules of the combinational strategy can be classified as three modalities: chemotherapy with subsequent DC vaccine (post-DC therapy); DC vaccine followed by chemotherapy (pre-DC therapy); concurrent DC vaccine with chemotherapy (con-DC therapy).The safety and efficacy of this combinatorial immunotherapy strategy and its potential mechanisms are discussed. Although we could not draw conclusions on optimal treatment schedule, we summarize some tips which may be beneficial to trial design in the future.

  13. Ecological benefits of dc power transmission

    SciTech Connect

    Kutuzova, N. B.

    2011-05-15

    The environmental effects of dc overhead transmission lines are examined. The major effects of ac and dc transmission lines are compared. Dc lines have advantages compared to ac lines in terms of electrical safety for people under the lines, biological effects, corona losses, and clearance width.

  14. 49 CFR 372.219 - Washington, DC

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 5 2013-10-01 2013-10-01 false Washington, DC 372.219 Section 372.219... ZONES, AND TERMINAL AREAS Commercial Zones § 372.219 Washington, DC The zone adjacent to, and... points within a line drawn 15 miles beyond the municipal limits of Washington, DC (c) All points...

  15. 49 CFR 372.219 - Washington, DC

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Washington, DC 372.219 Section 372.219... ZONES, AND TERMINAL AREAS Commercial Zones § 372.219 Washington, DC The zone adjacent to, and... points within a line drawn 15 miles beyond the municipal limits of Washington, DC (c) All points...

  16. 49 CFR 372.219 - Washington, DC

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 5 2014-10-01 2014-10-01 false Washington, DC 372.219 Section 372.219... ZONES, AND TERMINAL AREAS Commercial Zones § 372.219 Washington, DC The zone adjacent to, and... points within a line drawn 15 miles beyond the municipal limits of Washington, DC (c) All points...

  17. 49 CFR 372.219 - Washington, DC

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 5 2012-10-01 2012-10-01 false Washington, DC 372.219 Section 372.219... ZONES, AND TERMINAL AREAS Commercial Zones § 372.219 Washington, DC The zone adjacent to, and... points within a line drawn 15 miles beyond the municipal limits of Washington, DC (c) All points...

  18. 49 CFR 372.219 - Washington, DC

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 5 2011-10-01 2011-10-01 false Washington, DC 372.219 Section 372.219... ZONES, AND TERMINAL AREAS Commercial Zones § 372.219 Washington, DC The zone adjacent to, and... points within a line drawn 15 miles beyond the municipal limits of Washington, DC (c) All points...

  19. Full wave dc-to-dc converter using energy storage transformers

    NASA Technical Reports Server (NTRS)

    Moore, E. T.; Wilson, T. G.

    1969-01-01

    Full wave dc-to-dc converter, for an ion thrustor, uses energy storage transformers to provide a method of dc-to-dc conversion and regulation. The converter has a high degree of physical simplicity, is lightweight and has high efficiency.

  20. 14 CFR 93.339 - Requirements for operating in the DC SFRA, including the DC FRZ.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Requirements for operating in the DC SFRA, including the DC FRZ. 93.339 Section 93.339 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Washington, DC Metropolitan Area Special Flight Rules Area § 93.339 Requirements for operating in the DC...

  1. 14 CFR 93.339 - Requirements for operating in the DC SFRA, including the DC FRZ.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Requirements for operating in the DC SFRA, including the DC FRZ. 93.339 Section 93.339 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Washington, DC Metropolitan Area Special Flight Rules Area § 93.339 Requirements for operating in the DC...

  2. 14 CFR 93.339 - Requirements for operating in the DC SFRA, including the DC FRZ.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Requirements for operating in the DC SFRA, including the DC FRZ. 93.339 Section 93.339 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Washington, DC Metropolitan Area Special Flight Rules Area § 93.339 Requirements for operating in the DC...

  3. 14 CFR 93.339 - Requirements for operating in the DC SFRA, including the DC FRZ.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Requirements for operating in the DC SFRA, including the DC FRZ. 93.339 Section 93.339 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Washington, DC Metropolitan Area Special Flight Rules Area § 93.339 Requirements for operating in the DC...

  4. 14 CFR 93.339 - Requirements for operating in the DC SFRA, including the DC FRZ.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Requirements for operating in the DC SFRA, including the DC FRZ. 93.339 Section 93.339 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Washington, DC Metropolitan Area Special Flight Rules Area § 93.339 Requirements for operating in the DC...

  5. 75 FR 36579 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-30, DC-10-30F, DC-10-30F (KC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-28

    ... Corporation Model DC- 10-30, DC-10-30F, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F, and MD-10-30F...). SUMMARY: We propose to adopt a new airworthiness directive (AD) for certain Model DC-10-30, DC-10-30F, DC-10-30F (KC-10A and KDC-10), DC- 10-40, DC10-40F, and MD-10-30F airplanes. This proposed AD...

  6. 75 FR 61352 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-30, DC-10-30F, DC-10-30F (KC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-05

    ... Corporation Model DC- 10-30, DC-10-30F, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F, and MD-10-30F... new airworthiness directive (AD) for certain Model DC-10-30, DC-10-30F, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC- 10-40F, and MD-10-30F airplanes. This AD requires doing a one-time inspection of...

  7. DC-Powered Jumping Ring

    NASA Astrophysics Data System (ADS)

    Jeffery, Rondo N.; Amiri, Farhang

    2016-02-01

    The classroom jumping ring demonstration is nearly always performed using alternating current (AC), in which the ring jumps or flies off the extended iron core when the switch is closed. The ring jumps higher when cooled with liquid nitrogen (LN2). We have performed experiments using DC to power the solenoid and find similarities and significant differences from the AC case. In particular, the ring does not fly off the core but rises a short distance and then falls back. If the ring jumps high enough, the rising and the falling motion of the ring does not follow simple vertical motion of a projectile. This indicates that there are additional forces on the ring in each part of its motion. Four possible stages of the motion of the ring with DC are identified, which result from the ring current changing directions during the jump in response to a changing magnetic flux through the moving ring.

  8. Washington: A DC Circuit Tour

    NASA Astrophysics Data System (ADS)

    Halpern, Paul

    2010-12-01

    I explore the history of physics in Washington, D.C., and its environs through a tour of notable sites and personalities. Highlights include visits to the Smithsonian and Carnegie Institutions, stops at the Einstein Memorial, George Washington University, the University of Maryland, and the American Center for Physics, and biographical sketches of physicists Joseph Henry, George Gamow, Edward Teller, and others who worked in the District of Columbia.

  9. 76 FR 13543 - Airworthiness Directives; The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-14

    ... Model DC-9-81 (MD- 81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 Airplanes AGENCY... Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590. Hand Delivery: Deliver to Mail... stabilizer is similar in design and loading to that of the Model DC-9-81 (MD-81), DC- 9-82 (MD-82),...

  10. Silicon carbide DC-DC multilevel Cuk converter

    NASA Astrophysics Data System (ADS)

    Almalaq, Yasser; Alateeq, Ayoob; Matin, Mohammad

    2016-09-01

    In this paper, DC-DC multilevel cuk converter using silicon carbide (SiC) Components is presented. Cuk converter gives output voltage with negative polarity. This topology is useful for applications require high gain with limitation on duty cycle. The gain of the design can be enhanced by increasing the number of multiplier level (N). This relation between the gain and the number of levels is the major advantage of this multilevel cuk converter. In the proposed cuk converter, a single SiC MOSFET, 2N-1 SiC schottky diodes, 2N capacitors, 2 inductors, and single input voltage are used to supply a load with negative polarity. 300V input voltage, 50KHz switching frequency, and 75% duty cycle are the main parameters used in the design. The output parameters are 3KW power and -5.7 KV voltage. Because this design can be used in applications which temperature plays a critical role, the relation between increasing temperature and output voltage and power are tested. The design is simulated using LTspice software and the results are discussed.

  11. Arcing on dc power systems

    NASA Technical Reports Server (NTRS)

    Moores, Greg; Heller, R. P.; Sutanto, Surja; Dugal-Whitehead, Norma R.

    1992-01-01

    Unexpected and undesirable arcing on dc power systems can produce hazardous situations aboard space flights. The potential for fire and shock might exist in a situation where there is a broken conductor, a loose power connection, or a break in the insulation of the power cable. Such arcing has been found to be reproducible in a laboratory environment. Arcing tests show that the phenomena can last for several seconds and yet be undetectable by present protection schemes used in classical power relaying and remote power controller applications. This paper characterizes the arcing phenomena and suggests future research that is needed.

  12. DC Magnetics Measurement System Design

    NASA Technical Reports Server (NTRS)

    Mastny, Timothy

    2012-01-01

    This report will detail the updates to the magnetics measurement system design and testing procedures that are required for performing static (DC) magnetics testing of future flight hardware. An older magnetics testing system had to be integrated with new procedures and hardware to meet the demands of future testing programs and accommodate an upcoming magnetics tests. The next test will be for the Geostationary Operational Environmental Satellite R-Series (GOES-R), which will verify that the SAFT Battery component meets its specifications for magnetic cleanliness. The satellite is scheduled to launch in 2015 with magnetics testing to be completed on the battery in November 2012.

  13. Block clustering based on difference of convex functions (DC) programming and DC algorithms.

    PubMed

    Le, Hoai Minh; Le Thi, Hoai An; Dinh, Tao Pham; Huynh, Van Ngai

    2013-10-01

    We investigate difference of convex functions (DC) programming and the DC algorithm (DCA) to solve the block clustering problem in the continuous framework, which traditionally requires solving a hard combinatorial optimization problem. DC reformulation techniques and exact penalty in DC programming are developed to build an appropriate equivalent DC program of the block clustering problem. They lead to an elegant and explicit DCA scheme for the resulting DC program. Computational experiments show the robustness and efficiency of the proposed algorithm and its superiority over standard algorithms such as two-mode K-means, two-mode fuzzy clustering, and block classification EM.

  14. Power Strategy in DC/DC Converters to Increase Efficiency of Electrical Stimulators.

    PubMed

    Aqueveque, Pablo; Acuña, Vicente; Saavedra, Francisco; Debelle, Adrien; Lonys, Laurent; Julémont, Nicolas; Huberland, François; Godfraind, Carmen; Nonclercq, Antoine

    2016-06-13

    Power efficiency is critical for electrical stimulators. Battery life of wearable stimulators and wireless power transmission in implanted systems are common limiting factors. Boost DC/DC converters are typically needed to increase the supply voltage of the output stage. Traditionally, boost DC/DC converters are used with fast control to regulate the supply voltage of the output. However, since stimulators are acting as current sources, such voltage regulation is not needed. Banking on this, this paper presents a DC/DC conversion strategy aiming to increase power efficiency. It compares, in terms of efficiency, the traditional use of boost converters to two alternatives that could be implemented in future hardware designs.

  15. How Much DC Power is Necessary

    DTIC Science & Technology

    2010-04-01

    must transform essentially all of the available AC power to DC, including all of the power for the ship propulsion drive. This approach by the...in Fig. 1 convert the AC source power to DC and energize the associated DC busses. At the power levels anticipated, i.e., for ship propulsion load...for a ship propulsion application. We begin by assuming that the variable frequency power electronics associated with the rotor will only deliver

  16. Active dc filter for HVDC systems

    SciTech Connect

    Zhang, W. ); Asplund, G.

    1994-01-01

    This article is a case history of the installation of active dc filters for high-performance, low-cost harmonics filtering at the Lindome converter station in the Konti-Skan 2 HVDC transmission link between Denmark and Sweden. The topics of the article include harmonics, interference, and filters, Lindome active dc filter, active dc filter design, digital signal processor, control scheme, protection and fault monitoring, and future applications.

  17. DC circuits: II. Identification of foothold ideas in DC circuits

    NASA Astrophysics Data System (ADS)

    John, lgnatius; Allie, Saalih

    2017-01-01

    This is the second part of a broader investigation which explores the reasons behind the contextual variations in student responses at a fine-grained level. In the previous article (John 2017 Eur. J. Phys. 38 015701) it was established that the students’ responses are highly context dependent at a fine-grained level. This article presents the reason for the contextual variations of student responses from their free written responses. The result indicates that students who are being triggered by the productive resources during the engagement with the task will arrive at the correct (canonical) conclusion and those triggered by the unproductive resources will arrive at an incorrect conclusion. We identified the productive foothold ideas in a simple DC circuit with a single resistive element.

  18. Delta Clipper-Experimental (DC-X)

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Pictured here is a DC-XA Reusable Launch Vehicle (RLV) prototype concept with an RLV logo. The Delta Clipper-Experimental (DC-X) was originally developed by McDornell Douglas for the Department of Defense (DOD). The DC-XA is a single-stage-to-orbit, vertical takeoff/vertical landing, launch vehicle concept, whose development is geared to significantly reduce launch costs and will provide a test bed for NASA Reusable Launch Vehicle (RLV) technology as the Delta Clipper-Experimental Advanced (DC-XA).

  19. Evaluation of underground dc transmission systems

    NASA Astrophysics Data System (ADS)

    1982-03-01

    Progress in a program for evaluating underground dc transmission systems is reported. A basic load flow model was developed for a large ac power system. This model will be adjusted to produce representations for 4000, 8000, and 12,000 MW energy park. Load flow conditions for dc lines are being calculated. The stability of ac and dc are being examined. Short circuit duties are being calculated. Load flow computer runs are being made to demonstrate the suitability of developed ac and dc options.

  20. Simultaneous distribution of AC and DC power

    DOEpatents

    Polese, Luigi Gentile

    2015-09-15

    A system and method for the transport and distribution of both AC (alternating current) power and DC (direct current) power over wiring infrastructure normally used for distributing AC power only, for example, residential and/or commercial buildings' electrical wires is disclosed and taught. The system and method permits the combining of AC and DC power sources and the simultaneous distribution of the resulting power over the same wiring. At the utilization site a complementary device permits the separation of the DC power from the AC power and their reconstruction, for use in conventional AC-only and DC-only devices.

  1. Effect of Antioxidants on DC Tree and Grounded DC Tree in XLPE

    NASA Astrophysics Data System (ADS)

    Kawanami, Hiroshi; Komatsu, Isao; Sekii, Yasuo; Saito, Mitsugu; Sugi, Kazuyuki

    To study the effects of antioxidants on the initiation of the DC tree and the grounded DC tree, experiments were conducted using XLPE specimens containing phenolic and sulfur type antioxidants. Experimental results showed that sulfur type antioxidants in XLPE have the effect of increasing inception voltages of both the DC tree and the grounded DC tree. Based on results of those experiments, the mechanism of increase in the inception voltage of the DC tree and the grounded DC tree by antioxidants was examined along with the mechanism of polarity effects on those trees. Results showed a promotional effect of charge injection from a needle electrode by antioxidants, which are responsible for the increased inception voltages of the DC tree. Charge trapping by antioxidants explains the increase of inception voltages of the grounded DC tree.

  2. 76 FR 52225 - Airworthiness Directives; The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-22

    ... Model DC-9-81 (MD- 81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 Airplanes AGENCY... Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590. FOR FURTHER INFORMATION... ADs (b) None. Applicability (c) This AD applies to The Boeing Company Model DC-9-81 (MD-81),...

  3. High voltage DC power supply

    DOEpatents

    Droege, T.F.

    1989-12-19

    A high voltage DC power supply having a first series resistor at the output for limiting current in the event of a short-circuited output, a second series resistor for sensing the magnitude of output current, and a voltage divider circuit for providing a source of feedback voltage for use in voltage regulation is disclosed. The voltage divider circuit is coupled to the second series resistor so as to compensate the feedback voltage for a voltage drop across the first series resistor. The power supply also includes a pulse-width modulated control circuit, having dual clock signals, which is responsive to both the feedback voltage and a command voltage, and also includes voltage and current measuring circuits responsive to the feedback voltage and the voltage developed across the second series resistor respectively. 7 figs.

  4. High voltage DC power supply

    DOEpatents

    Droege, Thomas F.

    1989-01-01

    A high voltage DC power supply having a first series resistor at the output for limiting current in the event of a short-circuited output, a second series resistor for sensing the magnitude of output current, and a voltage divider circuit for providing a source of feedback voltage for use in voltage regulation is disclosed. The voltage divider circuit is coupled to the second series resistor so as to compensate the feedback voltage for a voltage drop across the first series resistor. The power supply also includes a pulse-width modulated control circuit, having dual clock signals, which is responsive to both the feedback voltage and a command voltage, and also includes voltage and current measuring circuits responsive to the feedback voltage and the voltage developed across the second series resistor respectively.

  5. HOx Photochemistry during DC3

    NASA Astrophysics Data System (ADS)

    Ren, X.; Mao, J.; Zhang, L.; Miller, D.; Brune, W. H.

    2013-12-01

    Measurements of OH, HO2 and OH reactivity were made as part of a much larger measurement suite from the NASA DC-8 aircraft during the Deep Convective Clouds and Chemistry (DC3) study in summer 2012. This mission, which was conducted over central North American region to investigate the impact of deep convection on upper tropospheric composition and chemistry, provides us an excellent opportunity to test oxidation chemistry in convection throughout the troposphere. Measured HOx are compared with the calculations using a box model that was constrained to in-situ measurements of long-lived chemicals. In general both measured OH and HO2 agree well with the model calculations within the measurement uncertainties. On average, the model tends to under-predict HO2 at low altitudes. No significant NO dependence was found for the observed-to-modeled OH and HO2 ratios, except the ratios are slightly less than unity when NO levels were greater than 1 ppbv indicating model over-prediction. The measured OH reactivity agrees generally well with the calculated OH reactivity using the measured OH reactants, with the measured OH reactivity higher than the calculated OH reactivity by about a factor of 1.2. We attribute this to possible missing OH reactants in the measurements. HOx budget analysis shows that the main HOx production was dominated by the ozone photolysis followed by the O(1D)+H2O reaction throughout the troposphere with small contributions from the photolysis of formaldehyde and hydrogen peroxide. The main HOx loss was the HO2+HO2 and HO2+RO2 reactions. The calculated net ozone production rates were observed to be about 1 ppb/h-1 between 10-12 km and 5 ppb h-1 below 1.5 km and were close to zero between 4-8 km. HOx behaviors under different conditions are is discussed.

  6. ALA 2010: Where to Eat in DC

    ERIC Educational Resources Information Center

    Library Journal, 2010

    2010-01-01

    As host to visitors and transplants from around the world, Washington, DC, benefits from the constant infusion of different cultures. Although most neighborhoods lack a unified culinary flavor, make no mistake: DC is a city of distinctive areas, each with its own style, ensuring that hungry American Library Association (ALA) 2010 conference…

  7. Dual wound dc brush motor gearhead

    NASA Technical Reports Server (NTRS)

    Henson, Barrie W.

    1986-01-01

    The design requirements, the design, development tests and problems, the qualification and life test and the findings of the strip examination of a dual wound DC brushed motor gearhead are described. It is the only space qualified dual wound dc brushed motor gearhead in Europe.

  8. Modeling of DC spacecraft power systems

    NASA Technical Reports Server (NTRS)

    Berry, F. C.

    1995-01-01

    Future spacecraft power systems must be capable of supplying power to various loads. This delivery of power may necessitate the use of high-voltage, high-power dc distribution systems to transmit power from the source to the loads. Using state-of-the-art power conditioning electronics such as dc-dc converters, complex series and parallel configurations may be required at the interface between the source and the distribution system and between the loads and the distribution system. This research will use state-variables to model and simulate a dc spacecraft power system. Each component of the dc power system will be treated as a multiport network, and a state model will be written with the port voltages as the inputs. The state model of a component will be solved independently from the other components using its state transition matrix. A state-space averaging method is developed first in general for any dc-dc switching converter, and then demonstrated in detail for the particular case of the boost power stage. General equations for both steady-state (dc) and dynamic effects (ac) are obtained, from which important transfer functions are derived and applied to a special case of the boost power stage.

  9. DC-based magnetic field controller

    DOEpatents

    Kotter, Dale K.; Rankin, Richard A.; Morgan, John P,.

    1994-01-01

    A magnetic field controller for laboratory devices and in particular to dc operated magnetic field controllers for mass spectrometers, comprising a dc power supply in combination with improvements to a hall probe subsystem, display subsystem, preamplifier, field control subsystem, and an output stage.

  10. Close-Range Gunfire around DC Schools

    ERIC Educational Resources Information Center

    Bieler, Sam; La Vigne, Nancy

    2014-01-01

    This report examines the incidence of gunfire as measured by gunshot detection technology using data from the 2011-2012 school year. It finds that a disproportionate volume of gunfire happened near a small share of DC schools. About half of DC schools covered by gunshot detection sensors are in close proximity to gunfire, and four schools were…

  11. DC-based magnetic field controller

    DOEpatents

    Kotter, D.K.; Rankin, R.A.; Morgan, J.P.

    1994-05-31

    A magnetic field controller is described for laboratory devices and in particular to dc operated magnetic field controllers for mass spectrometers, comprising a dc power supply in combination with improvements to a Hall probe subsystem, display subsystem, preamplifier, field control subsystem, and an output stage. 1 fig.

  12. DC KIDS COUNT e-Databook Indicators

    ERIC Educational Resources Information Center

    DC Action for Children, 2012

    2012-01-01

    This report presents indicators that are included in DC Action for Children's 2012 KIDS COUNT e-databook, their definitions and sources and the rationale for their selection. The indicators for DC KIDS COUNT represent a mix of traditional KIDS COUNT indicators of child well-being, such as the number of children living in poverty, and indicators of…

  13. 75 FR 446 - In the Matter of Certain DC-DC Controllers and Products; Notice of Investigation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-05

    ... Doc No: E9-31252] INTERNATIONAL TRADE COMMISSION [Inv. No. 337-TA-698] In the Matter of Certain DC--DC... sale for importation, and the sale within the United States after importation of certain DC--DC... Commission, 500 E Street, SW., Room 112, Washington, DC 20436, telephone 202-205-2000. Hearing...

  14. DC/DC Power Converter for Super-Capacitor Supplied by Electric Power Splitter

    NASA Astrophysics Data System (ADS)

    Haubert, T.; Mindl, P.

    The aim of the article is design of DC/DC converter and discussing of problematic supply using electric power splitter. The electric power splitter with AC/DC converter is source for the DC/DC converter, which is dedicated for charging and discharging of hybrid car drive super-capacitor energy storage. The electric power splitter is synchronous machine with two rotating parts. First rotor contains permanent magnet and the second rotor contains three-phase windings. The amplitude of output voltage depends on difference between first and second rotor speed. The main role of the DC/DC converter is to optimize energy content in super-capacitor storage used to acceleration and deceleration driving period of the passenger car with hybrid electric vehicle (HEV) drive system using electric power splitter.

  15. A High Voltage Ratio and Low Ripple Interleaved DC-DC Converter for Fuel Cell Applications

    PubMed Central

    Chang, Long-Yi; Chao, Kuei-Hsiang; Chang, Tsang-Chih

    2012-01-01

    This paper proposes a high voltage ratio and low ripple interleaved boost DC-DC converter, which can be used to reduce the output voltage ripple. This converter transfers the low DC voltage of fuel cell to high DC voltage in DC link. The structure of the converter is parallel with two voltage-doubler boost converters by interleaving their output voltages to reduce the voltage ripple ratio. Besides, it can lower the current stress for the switches and inductors in the system. First, the PSIM software was used to establish a proton exchange membrane fuel cell and a converter circuit model. The simulated and measured results of the fuel cell output characteristic curve are made to verify the correctness of the established simulation model. In addition, some experimental results are made to validate the effectiveness in improving output voltage ripple of the proposed high voltage ratio interleaved boost DC-DC converters. PMID:23365536

  16. Pulsed-DC DBD Plasma Actuators

    NASA Astrophysics Data System (ADS)

    Duong, Alan; McGowan, Ryan; Disser, Katherine; Corke, Thomas; Matlis, Eric

    2016-11-01

    A new powering system for dielectric barrier discharge (DBD) plasma actuators that utilizes a pulsed-DC waveform is presented. The plasma actuator arrangement is identical to most typical AC-DBD designs with staggered electrodes that are separated by a dielectric insulator. However instead of an AC voltage input to drive the actuator, the pulsed-DC utilizes a DC voltage source. The DC source is supplied to both electrodes, and remains constant in time for the exposed electrode. The DC source for the covered electrode is periodically grounded for very short instants and then allowed to rise to the source DC level. This process results in a plasma actuator body force that is significantly larger than that with an AC-DBD at the same voltages. The important characteristics used in optimizing the pulsed-DC plasma actuators are presented. Time-resolved velocity measurements near the actuator are further used to understand the underlying physics of its operation compared to the AC-DBD. Supported by NASA Glenn RC.

  17. High power density dc/dc converter: Selection of converter topology

    NASA Technical Reports Server (NTRS)

    Divan, Deepakraj M.

    1990-01-01

    The work involved in the identification and selection of a suitable converter topology is described. Three new dc/dc converter topologies are proposed: Phase-Shifted Single Active Bridge DC/DC Converter; Single Phase Dual Active Bridges DC/DC Converter; and Three Phase Dual Active Bridges DC/DC Converter (Topology C). The salient features of these topologies are: (1) All are minimal in structure, i.e., each consists of an input and output bridge, input and output filter and a transformer, all components essential for a high power dc/dc conversion process; (2) All devices of both the bridges can operate under near zero-voltage conditions, making possible a reduction of device switching losses and hence, an increase in switching frequency; (3) All circuits operate at a constant frequency, thus simplifying the task of the magnetic and filter elements; (4) Since, the leakage inductance of the transformer is used as the main current transfer element, problems associated with the diode reverse recovery are eliminated. Also, this mode of operation allows easy paralleling of multiple modules for extending the power capacity of the system; (5) All circuits are least sensitive to parasitic impedances, infact the parasitics are efficently utilized; and (6) The soft switching transitions, result in low electromagnetic interference. A detailed analysis of each topology was carried out. Based on the analysis, the various device and component ratings for each topology operating at an optimum point, and under the given specifications, are tabulated and discussed.

  18. Robust DC/DC converter control for polymer electrolyte membrane fuel cell application

    NASA Astrophysics Data System (ADS)

    Wang, Ya-Xiong; Yu, Duck-Hyun; Chen, Shi-An; Kim, Young-Bae

    2014-09-01

    This study investigates a robust controller in regulating the pulse width modulation (PWM) of a DC/DC converter for a polymer electrolyte membrane fuel cell (PEMFC) application. A significant variation in the output voltage of a PEMFC depends on the power requirement and prevents a PEMFC from directly connecting to a subsequent power bus. DC/DC converters are utilized to step-up or step-down voltage to match the subsequent power bus voltage. In this study, a full dynamic model, which includes a PEMFC and boost and buck DC/DC converters, is developed under MATLAB/Simulink environment for control. A robust PWM duty ratio control for the converters is designed using time delay control (TDC). This control enables state variables to accurately follow the dynamics of a reference model using time-delayed information of plant input and output information within a few sampling periods. To prove the superiority of the TDC performance, traditional proportional-integral control (PIC) and model predictive control (MPC) are designed and implemented, and the simulation results are compared. The efficacies of TDC for the PEMFC-fed PWM DC/DC converters are validated through experimental test results using a 100 W PEMFC as well as boost and buck DC/DC converters.

  19. Novel bidirectional DC-DC converters based on the three-state switching cell

    NASA Astrophysics Data System (ADS)

    da Silva Júnior, José Carlos; Robles Balestero, Juan Paulo; Lessa Tofoli, Fernando

    2016-05-01

    It is well known that there is an increasing demand for bidirectional DC-DC converters for applications that range from renewable energy sources to electric vehicles. Within this context, this work proposes novel DC-DC converter topologies that use the three-state switching cell (3SSC), whose well-known advantages over conventional existing structures are ability to operate at high current levels, while current sharing is maintained by a high frequency transformer; reduction of cost and dimensions of magnetics; improved distribution of losses, with consequent increase of global efficiency and reduction of cost associated to the need of semiconductors with lower current ratings. Three distinct topologies can be derived from the 3SSC: one DC-DC converter with reversible current characteristic able to operate in the first and second quadrants; one DC-DC converter with reversible voltage characteristic able to operate in the first and third quadrants and one DC-DC converter with reversible current and voltage characteristics able to operate in four quadrants. Only the topology with bidirectional current characteristic is analysed in detail in terms of the operating stages in both nonoverlapping and overlapping modes, while the design procedure of the power stage elements is obtained. In order to validate the theoretical assumptions, an experimental prototype is also implemented, so that relevant issues can be properly discussed.

  20. DC isolation and protection system and circuit

    NASA Technical Reports Server (NTRS)

    Wagner, Charles A. (Inventor); Kellogg, Gary V. (Inventor)

    1991-01-01

    A precision analog electronic circuit that is capable of sending accurate signals to an external device that has hostile electric characteristics, including the presence of very large common mode voltages. The circuit is also capable of surviving applications of normal mode overvoltages of up to 120 VAC/VDC for unlimited periods of time without damage or degradation. First, the circuit isolates the DC signal output from the computer. Means are then provided for amplifying the isolated DC signal. Further means are provided for stabilizing and protecting the isolating and amplifying means, and the isolated and amplified DC signal which is output to the external device, against overvoltages and overcurrents.

  1. Advanced DC/DC Converters Towards Higher Volumetric Efficiencies For Space Applications

    NASA Technical Reports Server (NTRS)

    Shaw, Harry; Shue, Jack; Liu, David; Wang, Bright; Plante, Jeanette

    2005-01-01

    A new emphasis on planetary exploration by NASA drives the need for small, high power DC/DC converters which are functionally modular. NASA GSFC and other government space organizations are supporting technology development in the DC/DC converter area to both meet new needs and to promote more sources of supply. New technologies which enable miniaturization such as embedded passive technologies and thermal management using high thermal conductivity materials are features of the new designs. Construction of some simple DC/DC converter core circuits using embedded components was found to be successful for increasing volumetric efficiency to 37 W/inch. The embedded passives were also able to perform satisfactorily in this application in cryogenic temperatures.

  2. Application handbook for a Standardized Control Module (SCM) for DC-DC converters, volume 1

    NASA Technical Reports Server (NTRS)

    Lee, F. C.; Mahmoud, M. F.; Yu, Y.

    1980-01-01

    The standardized control module (SCM) was developed for application in the buck, boost and buck/boost DC-DC converters. The SCM used multiple feedback loops to provide improved input line and output load regulation, stable feedback control system, good dynamic transient response and adaptive compensation of the control loop for changes in open loop gain and output filter time constraints. The necessary modeling and analysis tools to aid the design engineer in the application of the SCM to DC-DC Converters were developed. The SCM functional block diagram and the different analysis techniques were examined. The average time domain analysis technique was chosen as the basic analytical tool. The power stage transfer functions were developed for the buck, boost and buck/boost converters. The analog signal and digital signal processor transfer functions were developed for the three DC-DC Converter types using the constant on time, constant off time and constant frequency control laws.

  3. Nonlinear Phenomena and Resonant Parametric Perturbation Control in QR-ZCS Buck DC-DC Converters

    NASA Astrophysics Data System (ADS)

    Hsieh, Fei-Hu; Liu, Feng-Shao; Hsieh, Hui-Chang

    The purpose of this study is to investigate the chaotic phenomena and to control in current-mode controlled quasi-resonant zero-current-switching (QR-ZCS) DC-DC buck converters, and to present control of chaos by resonant parametric perturbation control methods. First of all, MATLAB/SIMULINK is used to derive a mathematical model for QR-ZCS DC-DC buck converters, and to simulate the converters to observe the waveform of output voltages, inductance currents and phase-plane portraits from the period-doubling bifurcation to chaos by changing the load resistances. Secondly, using resonant parametric perturbation control in QR-ZCS buck DC-DC converters, the simulation results of the chaotic converter form chaos state turn into stable state period 1, and improve ripple amplitudes of converters under the chaos, to verify the validity of the proposes method.

  4. Modelling and Simulation of Digital Compensation Technique for dc-dc Converter by Pole Placement

    NASA Astrophysics Data System (ADS)

    Shenbagalakshmi, R.; Sree Renga Raja, T.

    2015-09-01

    A thorough and effective analysis of the dc-dc converters is carried out in order to achieve the system stability and to improve the dynamic performance. A small signal modelling based on state space averaging technique for dc-dc converters is carried out. A digital state feedback gain matrix is derived by pole placement technique in order to achieve the stability of a completely controllable system. A prediction observer for the dc-dc converters is designed and a dynamic compensation (observer plus control law) is provided using separation principle. The output is very much improved with zero output voltage ripples, zero peak overshoot, and much lesser settling time in the range of ms and with higher overall efficiency (>90 %).

  5. DC-DC converters with reduced mass for trackers at the HL-LHC

    NASA Astrophysics Data System (ADS)

    Affolder, A.; Allongue, B.; Blanchot, G.; Faccio, F.; Fuentes, C.; Greenall, A.; Michelis, S.

    2011-11-01

    The development at CERN of low noise DC-DC converters for the powering of front-end systems enables the implementation of efficient powering schemes for the physics experiments at the HL-LHC. Recent tests made on the ATLAS short strip tracker modules confirm the full electromagnetic compatibility of the DC-DC converter prototypes with front-end detectors. The integration of the converters in the trackers front-ends needs to address also the material budget constraints. The impact of the DC-DC converters onto the material budget of the ATLAS tracker modules is discussed and mass reduction techniques are explored, leading to a compromise between electromagnetic compatibility and mass. Low mass shield implementations and Aluminum core inductors are proposed. Also, the impact on emitted noise due to a size reduction of critical components is discussed. Finally, material reduction techniques are discussed at the board layout and manufacturing levels.

  6. Test Results of Selected Commercial DC/DC Converters under Cryogenic Temperatures - A Digest

    NASA Technical Reports Server (NTRS)

    Patterson, Richard; Hammoud, Ahmad

    2010-01-01

    DC/DC converters are widely used in space power systems in the areas of power management and distribution, signal conditioning, and motor control. Design of DC/DC converters to survive cryogenic temperatures will improve the power system performance, simplify design, and reduce development and launch costs. In this work, the performance of nine COTS modular, low-tomedium power DC/DC converters was investigated under cryogenic temperatures. The converters were evaluated in terms of their output regulation, efficiency, and input and output currents. At a given temperature, these properties were obtained at various input voltages and at different load levels. A summary on the performance of the tested converters was given. More comprehensive testing and in-depth analysis of performance under long-term exposure to extreme temperatures are deemed necessary to establish the suitability of these and other devices for use in the harsh environment of space exploration missions.

  7. Power Strategy in DC/DC Converters to Increase Efficiency of Electrical Stimulators

    PubMed Central

    Aqueveque, Pablo; Acuña, Vicente; Saavedra, Francisco; Debelle, Adrien; Lonys, Laurent; Julémont, Nicolas; Huberland, François; Godfraind, Carmen; Nonclercq, Antoine

    2016-01-01

    Power efficiency is critical for electrical stimulators. Battery life of wearable stimulators and wireless power transmission in implanted systems are common limiting factors. Boost DC/DC converters are typically needed to increase the supply voltage of the output stage. Traditionally, boost DC/DC converters are used with fast control to regulate the supply voltage of the output. However, since stimulators are acting as current sources, such voltage regulation is not needed. Banking on this, this paper presents a DC/DC conversion strategy aiming to increase power efficiency. It compares, in terms of efficiency, the traditional use of boost converters to two alternatives that could be implemented in future hardware designs. PMID:27990232

  8. A SQUID series array dc current sensor

    NASA Astrophysics Data System (ADS)

    Beyer, J.; Drung, D.

    2008-09-01

    Superconducting quantum interference device (SQUID) sensors are used to sense changes in various physical quantities, which can be transformed into changes in the magnetic flux threading the SQUID loop. We have developed a novel SQUID array dc current sensor. The device is based on a series array of identical dc SQUIDs. An input signal current to be measured is coupled tightly but non-uniformly to the SQUID array elements. The input signal coupling to the individual array elements is chosen such that a single-valued, non-periodic overall voltage response is obtained. Flux offsets in the individual SQUIDs which would compromise the sensor voltage response are avoided or can be compensated. We present simulations and experimental results on the SQUID Array for Dc (SQUAD) current sensor current sensor performance. A dc current resolution of <1 nA in a measurement bandwidth of 0-25 Hz is achieved for an input inductance of LIn<3 nH.

  9. Tester periodically registers dc amplifier characteristics

    NASA Technical Reports Server (NTRS)

    Cree, D.; Wenzel, G. E.

    1966-01-01

    Motor-driven switcher-recorder periodically registers the zero drift and gain drift signals of a dc amplifier subjected to changes in environment. A time coding method is used since several measurements are shared on a single recorder trace.

  10. DC-8 Takeoff in Kiruna, Sweden

    NASA Video Gallery

    NASA is using a DC-8 aircraft as a flying science laboratory. The platform aircraft, based at NASA's Dryden Flight Research Center, Edwards, Calif., collects data for many experiments in support of...

  11. dc illusion and its experimental verification

    NASA Astrophysics Data System (ADS)

    Liu, Min; Lei Mei, Zhong; Ma, Xiang; Cui, Tie Jun

    2012-07-01

    Based on the transformation optics method, we propose a dc illusion device, which can transform a metallic object into a magnified dielectric object using anisotropic conducting materials. Utilizing the analogy between electric conductivities and resistor networks, we design and fabricate the device using metal film resistors. The practical measurement data agree very well with simulation results. The proposed dc illusion device is easy to process and measure, and thus has potential applications in various sectors.

  12. DC-8 MTP calibration for SOLVE-2

    NASA Technical Reports Server (NTRS)

    Mahoney, M. J.

    2003-01-01

    The Jet Propulsion Laboratory (JPL) Microwave Temperature Profiler (MTP) was the only instrument making temperature measurements at and below flight level on the DC-8 during the SOLVE-2 campaign. Many years of careful comparison of MTP measurements with radiosondes near the DC-8 flight track have shown that the flight level temperature can be determined to an accuracy of 0.2K relative to radiosondes.

  13. Brushless DC Motors, Velocity and Position Control of the Brushless DC Motor.

    DTIC Science & Technology

    1986-06-01

    DC motor was designed using the Hall effect sensors. In addition, the position control of the brushless DC motor was developed using an optical encoder to sense angular position changes and a microprocessor to provide the desired position control. A Pittman 5111 wdg 1 brushless DC motor was used for this study. The design of the digital tachometer and pulse width modulator for velocity control and the design of the Z-80 based microprocessor controller and software design are described in

  14. Analysis of high voltage step-up nonisolated DC-DC boost converters

    NASA Astrophysics Data System (ADS)

    Alisson Alencar Freitas, Antônio; Lessa Tofoli, Fernando; Junior, Edilson Mineiro Sá; Daher, Sergio; Antunes, Fernando Luiz Marcelo

    2016-05-01

    A high voltage step-up nonisolated DC-DC converter based on coupled inductors suitable to photovoltaic (PV) systems applications is proposed in this paper. Considering that numerous approaches exist to extend the voltage conversion ratio of DC-DC converters that do not use transformers, a detailed comparison is also presented among the proposed converter and other popular topologies such as the conventional boost converter and the quadratic boost converter. The qualitative analysis of the coupled-inductor-based topology is developed so that a design procedure can be obtained, from which an experimental prototype is implemented to validate the theoretical assumptions.

  15. High power density dc/dc converter: Component selection and design

    NASA Technical Reports Server (NTRS)

    Divan, Deepakraj M.

    1989-01-01

    Further work pertaining to design considerations for the new high power, high frequency dc/dc converters is discussed. The goal of the project is the development of high power, high power density dc/dc converters at power levels in the multi-kilowatt to megawatt range for aerospace applications. The prototype converter is rated for 50 kW at a switching frequency of 50 kHz, with an input voltage of 200 Vdc and an output of 2000 Vdc. The overall power density must be in the vicinity of 0.2 to 0.3 kg/kW.

  16. Egr2 induced during DC development acts as an intrinsic negative regulator of DC immunogenicity.

    PubMed

    Miah, Mohammad Alam; Byeon, Se Eun; Ahmed, Md Selim; Yoon, Cheol-Hee; Ha, Sang-Jun; Bae, Yong-Soo

    2013-09-01

    Early growth response gene 2 (Egr2), which encodes a zinc finger transcription factor, is rapidly and transiently induced in various cell types independently of de novo protein synthesis. Although a role for Egr2 is well established in T-cell development, Egr2 expression and its biological function in dendritic cells (DCs) have not yet been described. Here, we demonstrate Egr2 expression during DC development, and its role in DC-mediated immune responses. Egr2 is expressed in the later stage of DC development from BM precursor cells. Even at steady state, Egr2 is highly expressed in mouse splenic DCs. Egr2-knockdown (Egr2-KD) DCs showed increased levels of major histocompatability complex (MHC) class I and II and co-stimulatory molecules, and enhanced antigen uptake and migratory capacities. Furthermore, Egr2-KD abolished SOCS1 expression and signal transducer and activator of transcription 5 (STAT5) activation during DC development, probably resulting in the enhancement of IL-12 expression and Th1 immunogenicity of a DC vaccine. DC-mediated cytotoxic T lymphocyte (CTL) activation and antitumor immunity were significantly enhanced by Egr2-KD, and impaired by Egr2 overexpression in antigen-pulsed DC vaccines. These data suggest that Egr2 acts as an intrinsic negative regulator of DC immunogenicity and can be an attractive molecular target for DC vaccine development.

  17. Efficiency and Regulation of Commercial Low Power DC/DC Converter Modules at Low Temperatures

    NASA Technical Reports Server (NTRS)

    Elbuluk, Malik E.; Gerber, Scott; Hammoud, Ahmad; Patterson, Richard L.

    2000-01-01

    DC/DC converters that are capable of operating at cryogenic temperatures are anticipated to play an important role in the power systems of future NASA deep space missions. Design of these converters to survive cryogenic temperatures will improve the power system performance, and reduce development and launch costs. At the NASA Glenn Research Center Low Temperature Electronics Laboratory, several commercial off-the-shelf dc/dc converter modules were evaluated for their low temperature performance. Various parameters were investigated as a function of temperature, in the range of 20 C to -190 C. Data pertaining to the efficiency and voltage regulation of the tested converters is presented and discussed.

  18. Interleaved DC-DC Converter with Discrete Duty Cycle and Open Loop Control

    NASA Astrophysics Data System (ADS)

    Kroics, K.; Sokolovs, A.

    2016-08-01

    The authors present the control principle of the multiphase interleaved DC-DC converter that can be used to vastly reduce output current ripple of the converter. The control algorithm can be easily implemented by using microcontroller without current loop in each phase. The converter works in discontinuous conduction mode (DCM) but close to boundary conduction mode (BCM). The DC-DC converter with such a control algorithm is useful in applications that do not require precise current adjustment. The prototype of the converter has been built. The experimental results of the current ripple are presented in the paper.

  19. The application of standardized control and interface circuits to three dc to dc power converters.

    NASA Technical Reports Server (NTRS)

    Yu, Y.; Biess, J. J.; Schoenfeld, A. D.; Lalli, V. R.

    1973-01-01

    Standardized control and interface circuits were applied to the three most commonly used dc to dc converters: the buck-boost converter, the series-switching buck regulator, and the pulse-modulated parallel inverter. The two-loop ASDTIC regulation control concept was implemented by using a common analog control signal processor and a novel digital control signal processor. This resulted in control circuit standardization and superior static and dynamic performance of the three dc-to-dc converters. Power components stress control, through active peak current limiting and recovery of switching losses, was applied to enhance reliability and converter efficiency.

  20. ASTER Washington, D.C.

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The White House, the Jefferson Memorial, and the Washington Monument with its shadow are all visible in this image of Washington, D.C. With its 15-meter spatial resolution, ASTER can see individual buildings. Taken on June 1, 2000, this image covers an area 14 kilometers (8.5 miles) wide and 13.7 kilometers (8.2 miles) long in three bands of the reflected visible and infrared wavelength region. The combination of visible and near infrared bands displays vegetation in red and water in dark grays. The Potomac River flows from the middle left to the bottom center. The large red area west of the river is Arlington National Cemetery.

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high-resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping and monitoring dynamic conditions and temporal change. Examples of applications include monitoring glacial advances and retreats, potentially active volcanoes, thermal pollution, and coral reef degradation; identifying crop stress; determining cloud morphology and physical properties; evaluating wetlands

  1. 75 FR 65651 - In the Matter of Certain DC-DC Controllers and Products Containing Same; Notice of Commission...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-26

    ... COMMISSION In the Matter of Certain DC-DC Controllers and Products Containing Same; Notice of Commission..., DC 20436, telephone (202) 708-2532. Copies of non- confidential documents filed in connection with...., Washington, DC 20436, telephone (202) 205-2000. General information concerning the Commission may also...

  2. 75 FR 17433 - In the Matter of Certain DC-DC Controllers and Products Containing Same; Notice of Commission...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-06

    ... COMMISSION In the Matter of Certain DC-DC Controllers and Products Containing Same; Notice of Commission... Street, SW., Washington, DC 20436, telephone (202) 708-2532. Copies of non- confidential documents filed..., 500 E Street, SW., Washington, DC 20436, telephone (202) 205-2000. General information concerning...

  3. 76 FR 55109 - In the Matter of Certain DC-DC Controllers and Products Containing Same; Notice of Institution of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-06

    ... COMMISSION In the Matter of Certain DC-DC Controllers and Products Containing Same; Notice of Institution of... Trade Commission, 500 E Street, SW., Washington, DC 20436, telephone (202) 205-3061. Copies of all.... International Trade Commission, 500 E Street, SW., Washington, DC 20436, telephone 202-205-2000....

  4. 75 FR 28283 - In the Matter of: Certain DC-DC Controllers and Products Containing Same; Notice of Commission...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-20

    ... COMMISSION In the Matter of: Certain DC-DC Controllers and Products Containing Same; Notice of Commission..., 500 E Street, SW., Washington, DC 20436, telephone (202) 708-2532. Copies of non- confidential... Commission, 500 E Street, SW., Washington, DC 20436, telephone (202) 205-2000. General information...

  5. 75 FR 65655 - In the Matter of Certain DC-DC Controllers and Products Containing Same; Notice of Commission...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-26

    ... COMMISSION In the Matter of Certain DC-DC Controllers and Products Containing Same; Notice of Commission..., DC 20436, telephone (202) 708-2532. Copies of non- confidential documents filed in connection with...., Washington, DC 20436, telephone (202) 205-2000. General information concerning the Commission may also...

  6. Single Event Burnout in DC-DC Converters for the LHC Experiments

    SciTech Connect

    Claudio H. Rivetta et al.

    2001-09-24

    High voltage transistors in DC-DC converters are prone to catastrophic Single Event Burnout in the LHC radiation environment. This paper presents a systematic methodology to analyze single event effects sensitivity in converters and proposes solutions based on de-rating input voltage and output current or voltage.

  7. Regulation of a lightweight high efficiency capacitator diode voltage multiplier dc-dc converter

    NASA Technical Reports Server (NTRS)

    Harrigill, W. T., Jr.; Myers, I. T.

    1976-01-01

    A method for the regulation of a capacitor diode voltage multiplier dc-dc converter has been developed which has only minor penalties in weight and efficiency. An auxiliary inductor is used, which only handles a fraction of the total power, to control the output voltage through a pulse width modulation method in a buck boost circuit.

  8. Regulation of a lightweight high efficiency capacitor diode voltage multiplier dc-dc converter

    NASA Technical Reports Server (NTRS)

    Harrigill, W. T., Jr.; Myers, I. T.

    1976-01-01

    A method for the regulation of a capacitor diode voltage multiplier dc-dc converter has been developed which has only minor penalties in weight and efficiency. An auxiliary inductor is used, which only handles a fraction of the total power, to control the output voltage through a pulse width modulation method in a buck boost circuit.

  9. Low noise DC to DC converters for the sLHC experiments

    NASA Astrophysics Data System (ADS)

    Allongue, B.; Blanchot, G.; Faccio, F.; Fuentes, C.; Michelis, S.; Orlandi, S.

    2010-11-01

    The development of front-end systems for the ATLAS tracker at the sLHC is now in progress and the availability of radiation tolerant buck converter ASICs enables the implementation of DC to DC converter based powering schemes. The front-end systems powered in this manner will be exposed to the radiated and conducted noise emitted by the converters. The electromagnetic compatibility between DC to DC converters and ATLAS short strip tracker hybrid prototypes has been studied with specific susceptibility tests. Different DC to DC converter prototypes have been designed following a noise optimization methodology to match the noise requirements of these front-end systems. The DC to DC converter developed in this manner presents a negligible emission of noise that was confirmed by system tests on an ATLAS tracker front-end module prototype. As a result of this, power converters can now be integrated in close vicinity of front-end chips without compromising their overall noise performance.

  10. Modelling, Simulation and Construction of a DC/DC Boost Power Converter: A School Experimental System

    ERIC Educational Resources Information Center

    Silva-Ortigoza, R.; Silva-Ortigoza, G.; Hernandez-Guzman, V. M.; Saldana-Gonzalez, G.; Marcelino-Aranda, M.; Marciano-Melchor, M.

    2012-01-01

    We introduce a dc/dc boost power converter as a didactic prototype intended to support courses on electric circuit analysis experimentally. The corresponding mathematical model is obtained, the converter is designed and an experimental setup is described, constructed and tested. Simplicity of construction as well as low cost of components renders…

  11. DC-DC conversion powering schemes for the CMS tracker at Super-LHC

    NASA Astrophysics Data System (ADS)

    Klein, K.; Feld, L.; Jussen, R.; Karpinski, W.; Merz, J.; Sammet, J.

    2010-07-01

    The CMS experiment at the Large Hadron Collider (LHC) at CERN, Geneva, houses the largest silicon strip tracker ever built. For the foreseen luminosity upgrade of the LHC, the Super-LHC, however, a completely new silicon tracker will have to be constructed. One out of several major improvements currently under consideration is the implementation of a track trigger, with tracking information being provided to the first level trigger. Such an intelligent tracker design, utilising fast digital readout electronics, will most certainly lead to an increased power consumption, compared to today's tracker. In combination with the desire to reduce the amount of passive material inside the tracking volume and the impracticality to exchange or even add additional supply cables, a novel powering scheme will be inevitable. In this article a powering scheme based on DC-DC conversion is proposed, and requirements for the DC-DC converters are discussed. Studies of important DC-DC converter quantities such as the power efficiency, conducted and radiated noise levels, and material budget are presented, and a possible implementation of DC-DC buck converters into one proposed track trigger layout is sketched.

  12. Improved DC Gun Insulator Assembly

    SciTech Connect

    Sah, R.; Dudas, A.; Neubauer, M. L.; Poelker, M.; Surles-Law, K. E.L.

    2010-05-23

    Many user fa­cil­i­ties such as syn­chrotron ra­di­a­tion light sources and free elec­tron lasers re­quire ac­cel­er­at­ing struc­tures that sup­port elec­tric fields of 10-100 MV/m, es­pe­cial­ly at the start of the ac­cel­er­a­tor chain where ce­ram­ic in­su­la­tors are used for very high gra­di­ent DC guns. These in­su­la­tors are dif­fi­cult to man­u­fac­ture, re­quire long com­mis­sion­ing times, and often ex­hib­it poor re­li­a­bil­i­ty. Two tech­ni­cal ap­proach­es to solv­ing this prob­lem will be in­ves­ti­gat­ed. First­ly, in­vert­ed ce­ram­ics offer so­lu­tions for re­duced gra­di­ents be­tween the elec­trodes and ground. An in­vert­ed de­sign will be pre­sent­ed for 350 kV, with max­i­mum gra­di­ents in the range of 5-10 MV/m. Sec­ond­ly, novel ce­ram­ic man­u­fac­tur­ing pro­cess­es will be stud­ied, in order to pro­tect triple junc­tion lo­ca­tions from emis­sion, by ap­ply­ing a coat­ing with a bulk re­sis­tiv­i­ty. The pro­cess­es for cre­at­ing this coat­ing will be op­ti­mized to pro­vide pro­tec­tion as well as be used to coat a ce­ram­ic with an ap­pro­pri­ate gra­di­ent in bulk re­sis­tiv­i­ty from the vac­u­um side to the air side of an HV stand­off ce­ram­ic cylin­der. Ex­am­ple in­su­la­tor de­signs are being com­put­er mod­elled, and in­su­la­tor sam­ples are being man­u­fac­tured and test­ed

  13. Pulsed dc self-sustained magnetron sputtering

    SciTech Connect

    Wiatrowski, A.; Posadowski, W. M.; Radzimski, Z. J.

    2008-09-15

    The magnetron sputtering has become one of the commonly used techniques for industrial deposition of thin films and coatings due to its simplicity and reliability. At standard magnetron sputtering conditions (argon pressure of {approx}0.5 Pa) inert gas particles (necessary to sustain discharge) are often entrapped in the deposited films. Inert gas contamination can be eliminated during the self-sustained magnetron sputtering (SSS) process, where the presence of the inert gas is not a necessary requirement. Moreover the SSS process that is possible due to the high degree of ionization of the sputtered material also gives a unique condition during the transport of sputtered particles to the substrate. So far it has been shown that the self-sustained mode of magnetron operation can be obtained using dc powering (dc-SSS) only. The main disadvantage of the dc-SSS process is its instability related to random arc formation. In such case the discharge has to be temporarily extinguished to prevent damaging both the magnetron source and power supply. The authors postulate that pulsed powering could protect the SSS process against arcs, similarly to reactive pulsed magnetron deposition processes of insulating thin films. To put this concept into practice, (i) the high enough plasma density has to be achieved and (ii) the type of pulsed powering has to be chosen taking plasma dynamics into account. In this article results of pulsed dc self-sustained magnetron sputtering (pulsed dc-SSS) are presented. The planar magnetron equipped with a 50 mm diameter and 6 mm thick copper target was used during the experiments. The maximum target power was about 11 kW, which corresponded to the target power density of {approx}560 W/cm{sup 2}. The magnetron operation was investigated as a function of pulse frequency (20-100 kHz) and pulse duty factor (50%-90%). The discharge (argon) extinction pressure level was determined for these conditions. The plasma emission spectra (400-410 nm range

  14. Homopolar dc motor and trapped flux brushless dc motor using high temperature superconductor materials

    SciTech Connect

    Crapo, A.D.; Lloyd, J.D. )

    1991-03-01

    This paper reports on two motors designed and built for use with high temperature superconductor (HTSC) materials. They are a homopolar DC motor that will use HTSC field windings and a brushless DC motor that will use bulk HTSC material to trap flux in steel rotor poles. The HTSC field windings of the homopolar DC motor are designed to operate at 1000 Amperes/cm{sup 2} in a 0.010 Tesla (100 Gauss) field. In order to maximize torque in the homopolar DC motor, an iron magnetic circuit with small air gaps gives maximum flux for minimum Ampere turns in the field. A copper field winding version of the homopolar DC motor has been tested while the authors wait for 575 Ampere turn HTSC coils.

  15. Lattice animals: dc=8 for trees

    NASA Astrophysics Data System (ADS)

    Ruskin, H. J.; Duarte, J. A. M. S.

    1982-09-01

    The asymptotic behavior of the total number of treelike clusters (lattice trees) on the hypercubic system is investigated for d>=4 by the method of series expansions. Interest centers on ascertaining the critical dimension, dc, at which the prefactor exponent θ attains its mean-field value. We present results for θ and for the cluster growth parameter λ for d=4 to 9. The λ values are close to within a few percent of those found for the general animal case. Results for θ have large uncertainties in the dimensions of interest, and the mean-field value is approached very gradually with d, so that the possibility of a lower value for dc cannot be completely discarded. Nevertheless, the available evidence suggests that dc=8 for lattice trees. This supports the findings of Lubensky and Isaacson in their recent work on lattice animals and dilute branched polymers.

  16. Ramp technique for dc partial discharge testing

    NASA Astrophysics Data System (ADS)

    Bever, R. S.

    1985-02-01

    The partial discharge (PD) data presently obtained by means of a stepwise ramp technique, for the cases of high voltage (HV) components and such resin-packaged HV devices as the Space Telescope's Faint Object Camera, is acquired separately on part-way ramps to rated voltage and on the intermediate voltage plateaus. For test specimens intended for dc service, this ramp method yields more data on insulation integrity than quiescent dc measurements, especially in the case of specimens of high resistivity which causes the discharge frequency to be deceptively low at constant dc voltage. During upward ramping the voltage distribution is capacitive, and the PD behavior resembles that of an ac test. Many more pulses are obtained in the voids without the heat otherwise generated by the application of 60-Hz ac. PD histograms are presented for various materials, with and without intentional defects.

  17. New Experimental Data in DC745U

    SciTech Connect

    Ortiz-Acosta, Denisse; Cady, Carl; Densmore, Crystal

    2012-06-18

    The objectives of this project are: (1) study the molecular and mechanical properties of DC745U - (a) DC745U is a silicone elastomer used in several weapons systems, (b) depending on their chemistry and formulation, polymers can be susceptible to damage and failures due to weak chemical linkages and physical interactions, (c) inefficient production processes can generate heterogeneities throughout the material that can contribute negatively to the overall performance and lifetime of the polyer, (d) aging, long-term thermal and radioactive conditions, and mechanical strains can affect the materials network structure and contribute to the degradation of the production; (2) characterization of DC745U materials cured under different conditions to determine possible differences to the polymer structure; and (3) this work is relevant to mission-critical programs and for supporting programmatic work for weapon research.

  18. Three phase full wave dc motor decoder

    NASA Technical Reports Server (NTRS)

    Studer, P. A. (Inventor)

    1977-01-01

    A three phase decoder for dc motors is disclosed which employs an extremely simple six transistor circuit to derive six properly phased output signals for fullwave operation of dc motors. Six decoding transistors are coupled at their base-emitter junctions across a resistor network arranged in a delta configuration. Each point of the delta configuration is coupled to one of three position sensors which sense the rotational position of the motor. A second embodiment of the invention is disclosed in which photo-optical isolators are used in place of the decoding transistors.

  19. DC Characterization of the Coaxial Superconducting Cable

    NASA Astrophysics Data System (ADS)

    Šouc, J.; Gömöry, F.; Vojenčiak, M.; Frolek, L.; Isfort, D.; Ehrenberg, J.; Bock, J.

    2008-01-01

    Coaxial cable model with superconducting core and superconducting shield conductor was constructed and tested in DC regime. While the core was already examined in our previous works, in this contribution the detailed study of the superconducting shield conductor in DC conditions is presented. It consists of 16 ReBCO coated tapes with critical current 35 A each connected in parallel. Using shunts with known values placed in series the currents in individual tapes were possible to measure. Distribution of the total cable current into the individual tapes was monitored and its influence on critical current of the cable is discussed.

  20. "DC:0-3" to "DC:0-3R" to "DC:0-5": A New Edition

    ERIC Educational Resources Information Center

    Zeanah, Charles H., Jr.; Carter, Alice; Cohen, Julie; Egger, Helen; Keren, Miri; Gleason, Mary Margaret; Lieberman, Alicia F.; Mulrooney, Kathleen; Oser, Cindy

    2015-01-01

    Originally published in 1994 by ZERO TO THREE as the "Diagnostic Classification of Mental Health and Developmental Disorders of Infancy and Early Childhood" ("DC:0-3") and revised in 2005 by ZERO TO THREE as the "Diagnostic Classification of Mental Health and Developmental Disorders of Infancy and Early Childhood, Revised…

  1. Homopolar dc motor and trapped flux brushless dc motor using high temperature superconductor materials

    NASA Astrophysics Data System (ADS)

    Crapo, Alan D.; Lloyd, Jerry D.

    1991-03-01

    Two motors have been designed and built for use with high-temperature superconductor (HTSC) materials. They are a homopolar dc motor that uses HTSC field windings and a brushless dc motor that uses bulk HTSC materials to trap flux in steel rotor poles. The HTSC field windings of the homopolar dc motor are designed to operate at 1000 A/sq cm in a 0.010-T field. In order to maximize torque in the homopolar dc motor, an iron magnetic circuit with small air gaps gives maximum flux for minimum Ampere turns in the field. A copper field winding version of the homopolar dc motor has been tested while waiting for 575 A turn HTSC coils. The trapped flux brushless dc motor has been built and is ready to test melt textured bulk HTSC rings that are currently being prepared. The stator of the trapped flux motor will impress a magnetic field in the steel rotor poles with warm HTSC bulk rings. The rings are then cooled to 77 K to trap the flux in the rotor. The motor can then operate as a brushless dc motor.

  2. 75 FR 6162 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-81 (MD-81), DC-9-82 (MD-82...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-08

    ... Corporation Model DC- 9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 Airplanes... Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 airplanes. This... material fatigue from normal flap operating loads. We are proposing this AD to detect and correct...

  3. 75 FR 34661 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-81 (MD-81), DC-9-82 (MD-82...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-18

    ... Corporation Model DC- 9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 Airplanes...: We propose to adopt a new airworthiness directive (AD) for certain Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9- 87 (MD-87), and MD-88 airplanes. This proposed AD would...

  4. 75 FR 47199 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-10 Series Airplanes, DC-9-30...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-05

    ... Douglas Corporation Model DC- 9-10 Series Airplanes, DC-9-30 Series Airplanes, DC-9-81 (MD-81) Airplanes, DC-9-82 (MD-82) Airplanes, DC-9-83 (MD-83) Airplanes, DC-9- 87 (MD-87) Airplanes, MD-88 Airplanes... directive (AD), which applies to all McDonnell Douglas Model DC-9-10 series airplanes, DC-9-30...

  5. 75 FR 80744 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-81 (MD-81), DC-9-82 (MD-82...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-23

    ... Corporation Model DC- 9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 Airplanes...: We propose to adopt a new airworthiness directive (AD) for all Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD- 87) and MD-88 airplanes. This proposed AD would require...

  6. Comparison of solar panel cooling system by using dc brushless fan and dc water

    NASA Astrophysics Data System (ADS)

    Irwan, Y. M.; Leow, W. Z.; Irwanto, M.; M, Fareq; Hassan, S. I. S.; Safwati, I.; Amelia, A. R.

    2015-06-01

    The purpose of this article is to discuss comparison of solar panel cooling system by using DC brushless fan and DC water pump. Solar photovoltaic (PV) power generation is an interesting technique to reduce non-renewable energy consumption and as a renewable energy. The temperature of PV modules increases when it absorbs solar radiation, causing a decrease in efficiency. A solar cooling system is design, construct and experimentally researched within this work. To make an effort to cool the PV module, Direct Current (DC) brushless fan and DC water pump with inlet/outlet manifold are designed for constant air movement and water flow circulation at the back side and front side of PV module representatively. Temperature sensors were installed on the PV module to detect temperature of PV. PIC microcontroller was used to control the DC brushless fan and water pump for switch ON or OFF depend on the temperature of PV module automatically. The performance with and without cooling system are shown in this experiment. The PV module with DC water pump cooling system increase 3.52%, 36.27%, 38.98%in term of output voltage, output current, output power respectively. It decrease 6.36 °C compare than to PV module without DC water pump cooling system. While DC brushless fan cooling system increase 3.47%, 29.55%, 32.23%in term of output voltage, output current, and output power respectively. It decrease 6.1 °C compare than to PV module without DC brushless fan cooling system. The efficiency of PV module with cooling system was increasing compared to PV module without cooling system; this is because the ambient temperature dropped significantly. The higher efficiency of PV cell, the payback period of the system can be shorted and the lifespan of PV module can also be longer.

  7. New Logic Circuit with DC Parametric Excitation

    NASA Astrophysics Data System (ADS)

    Sugahara, Masanori; Kaneda, Hisayoshi

    1982-12-01

    It is shown that dc parametric excitation is possible in a circuit named JUDO, which is composed of two resistively-connected Josephson junctions. Simulation study proves that the circuit has large gain and properties suitable for the construction of small, high-speed logic circuits.

  8. A passive DC current sensing methodology

    NASA Astrophysics Data System (ADS)

    Wang, Dong F.; Liu, Huan; Li, Xiaodong; Li, Yang; Xian, Weikang

    2016-10-01

    This paper proposes a method for passive sensing a two-wire DC current without using any cord separator. In this method, a piezoelectric thin-film cantilever with a micro-magnet on its end is positioned near a power cord. The DC current in the power cord induces a magnetic field, which generates a magnetic force acting on the micro-magnet. Consequently, the piezoelectric cantilever is bent and induces an output voltage that is sensitive to small variations of DC currents. A prototype device has been fabricated and experimentally studied. It was found that the initial peak amplitude of the piezoelectric output voltage increases linearly with the DC current value upon "ON-OFF" switching. Compared to the Hall-effect based sensing, this method has the advantages of no need of driving voltage or cord separators even for two-wire appliance cords. Apart from the conventional consumer electronics, this method may have a wide application foreground in the new emerging fields, such as energy vehicles, lithium ion battery, or smart power grid.

  9. Electrical Anomalies Observed During DC3

    NASA Technical Reports Server (NTRS)

    Lang, Timothy J.; Rutledge, Steven A.; Dolan, Brenda; Krehbiel, Paul; Rison, William; Lindsey, Daniel T.; Lyons, Walt

    2013-01-01

    The primary scientific goals of DC3 involved improving our understanding of the chemical impacts of thunderstorms and their anvils. However, the Colorado domain provided opportunities to study other interesting phenomena, including the potential impacts of smoke ingestion on convection and thunderstorms, electrification processes in smoke plumes and pyrocumulonimbus clouds, and the production of sprites by unconventional thunderstorm.

  10. Manufacturing development of DC-10 advanced rudder

    NASA Technical Reports Server (NTRS)

    Cominsky, A.

    1979-01-01

    The design, manufacture, and ground test activities during development of production methods for an advanced composite rudder for the DC-10 transport aircraft are described. The advanced composite aft rudder is satisfactory for airline service and a cost saving in a full production manufacturing mode is anticipated.

  11. Computerized Torque Control for Large dc Motors

    NASA Technical Reports Server (NTRS)

    Willett, Richard M.; Carroll, Michael J.; Geiger, Ronald V.

    1987-01-01

    Speed and torque ranges in generator mode extended. System of shunt resistors, electronic switches, and pulse-width modulation controls torque exerted by large, three-phase, electronically commutated dc motor. Particularly useful for motor operating in generator mode because it extends operating range to low torque and high speed.

  12. Gravity Compensation Technique Uses Small dc Motor

    NASA Technical Reports Server (NTRS)

    Hollow, Richard

    1988-01-01

    Small dc servomotor powered by simple constant-current source and with suitable gearing used to cancel effect of gravity upon load. Lead-screw positioning system has load counterbalanced by small supplementary motor powered by constant current source. Motor lighter and more compact alternative to counterbalance. Used in variety of mechanical systems where load positioned or accelerated in vertical plane.

  13. Halbach array DC motor/generator

    DOEpatents

    Merritt, B.T.; Dreifuerst, G.R.; Post, R.F.

    1998-01-06

    A new configuration of DC motor/generator is based on a Halbach array of permanent magnets. This motor does not use ferrous materials so that the only losses are winding losses and losses due to bearings and windage. An ``inside-out`` design is used as compared to a conventional motor/generator design. The rotating portion, i.e., the rotor, is on the outside of the machine. The stationary portion, i.e., the stator, is formed by the inside of the machine. The rotor contains an array of permanent magnets that provide a uniform field. The windings of the motor are placed in or on the stator. The stator windings are then ``switched`` or ``commutated`` to provide a DC motor/generator much the same as in a conventional DC motor. The commutation can be performed by mechanical means using brushes or by electronic means using switching circuits. The invention is useful in electric vehicles and adjustable speed DC drives. 17 figs.

  14. Halbach array DC motor/generator

    DOEpatents

    Merritt, Bernard T.; Dreifuerst, Gary R.; Post, Richard F.

    1998-01-01

    A new configuration of DC motor/generator is based on a Halbach array of permanent magnets. This motor does not use ferrous materials so that the only losses are winding losses and losses due to bearings and windage. An "inside-out" design is used as compared to a conventional motor/generator design. The rotating portion, i.e., the rotor, is on the outside of the machine. The stationary portion, i.e., the stator, is formed by the inside of the machine. The rotor contains an array of permanent magnets that provide a uniform field. The windings of the motor are placed in or on the stator. The stator windings are then "switched" or "commutated" to provide a DC motor/generator much the same as in a conventional DC motor. The commutation can be performed by mechanical means using brushes or by electronic means using switching circuits. The invention is useful in electric vehicles and adjustable speed DC drives.

  15. DC3 Data and Information Page

    Atmospheric Science Data Center

    2015-03-16

    ... species, and d) chemistry in the anvil. To quantify the changes in chemistry and composition after active convection, focusing on a) ... hours after convection and b) the seasonal transition of the chemical composition of the upper troposphere.   The DC3 aircraft ...

  16. DC multi-infeed study. Final report

    SciTech Connect

    Szechtman, M.; Pilotto, L.A.S.; Ping, W.W.; Salgado, E.; Dias de Carvalho, A.R.C.; Long, W.F.; Alvarado, F.L.; DeMarco, C.L.; Canizares, C.A.; Wey, A.

    1994-12-01

    An HVdc multiconverter configuration results when more than one converter station is located within the same electrical region. Such a situation will be a natural consequence of the growing use of the HVdc technology. Relevant questions relating to multiconverter configurations have been analyzed in the scope of this research project. In particular, special emphasis has been devoted to the HVdc inverter multiinfeed schemes, since such a situation will be more commonly found in future applications and usually results in the most severe ac/dc interactions. The main purpose of this project is to present a general insight into the potential problems resulting from multiinfeed HVdc operation, using networks based on realistic power system configurations. Power system studies have been performed using several digital (Load-Flow, Transient Stability, Eigenvalue and EMTP programs) and analog (DC Simulator) tools in a complementary basis to investigate both low and high frequency interaction phenomena. The project was conducted to evaluate the technical aspects of the various ac/dc and dc/dc interactions. It addressed small signal stability, an overview of the entire system transient and dynamic stability, some aspects of the ac voltage stability problem and HVdc control stability including the effects of the VDCOL units and possible occurrence of commutation failures at inverter stations after recovery from faults. This report identifies the potential problems resulting from multiinfeed situations and proposes practical solutions. It also presents a survey on how the various HVdc system controllers can be coordinated to provide the interconnected ac system with an improved dynamic performance, a high level of operational flexibility and the maximization of the overall system loadability.

  17. A Nonlinear Digital Control Solution for a DC/DC Power Converter

    NASA Technical Reports Server (NTRS)

    Zhu, Minshao

    2002-01-01

    A digital Nonlinear Proportional-Integral-Derivative (NPID) control algorithm was proposed to control a 1-kW, PWM, DC/DC, switching power converter. The NPID methodology is introduced and a practical hardware control solution is obtained. The design of the controller was completed using Matlab (trademark) Simulink, while the hardware-in-the-loop testing was performed using both the dSPACE (trademark) rapid prototyping system, and a stand-alone Texas Instruments (trademark) Digital Signal Processor (DSP)-based system. The final Nonlinear digital control algorithm was implemented and tested using the ED408043-1 Westinghouse DC-DC switching power converter. The NPID test results are discussed and compared to the results of a standard Proportional-Integral (PI) controller.

  18. Cryogenic Evaluation of an Advanced DC/DC Converter Module for Deep Space Applications

    NASA Technical Reports Server (NTRS)

    Elbuluk, Malik E.; Hammoud, Ahmad; Gerber, Scott S.; Patterson, Richard

    2003-01-01

    DC/DC converters are widely used in power management, conditioning, and control of space power systems. Deep space applications require electronics that withstand cryogenic temperature and meet a stringent radiation tolerance. In this work, the performance of an advanced, radiation-hardened (rad-hard) commercial DC/DC converter module was investigated at cryogenic temperatures. The converter was investigated in terms of its steady state and dynamic operations. The output voltage regulation, efficiency, terminal current ripple characteristics, and output voltage response to load changes were determined in the temperature range of 20 to -140 C. These parameters were obtained at various load levels and at different input voltages. The experimental procedures along with the results obtained on the investigated converter are presented and discussed.

  19. DC-DC power converter research for Orbiter/Station power exchange

    NASA Technical Reports Server (NTRS)

    Ehsani, M.

    1993-01-01

    This project was to produce innovative DC-DC power converter concepts which are appropriate for the power exchange between the Orbiter and the Space Station Freedom (SSF). The new converters must interface three regulated power buses on SSF, which are at different voltages, with three fuel cell power buses on the Orbiter which can be at different voltages and should be tracked independently. Power exchange is to be bi-directional between the SSF and the Orbiter. The new converters must satisfy the above operational requirements with better weight, volume, efficiency, and reliability than is available from the present conventional technology. Two families of zero current DC-DC converters were developed and successfully adapted to this application. Most of the converters developed are new and are presented.

  20. Research of digital controlled DC/DC converter based on STC12C5410AD

    NASA Astrophysics Data System (ADS)

    Chen, Dan-Jiang; Jin, Xin; Xiao, Zhi-Hong

    2010-02-01

    In order to study application of digital control technology on DC/DC converter, principle of increment mode PID control algorithm was analyzed in the paper. Then, a SCM named STC12C5410AD was introduced with its internal resources and characteristics. The PID control algorithm can be implemented easily based on it. The output of PID control was used to change the value of a variable that is 255 times than duty cycle, and this reduced the error of calculation. The valid of the presented algorithm was verified by an experiment for a BUCK DC/DC converter. The experimental results indicated that output voltage of the BUCK converter is stable with low ripple.

  1. GaN HFET-Based DC/DC Converters for Low Power RF Satellite Equipment

    NASA Astrophysics Data System (ADS)

    Delamare, Guillaume; Maynadier, Paul; Schneider, Henri

    2014-08-01

    This paper presents the evaluation and prototyping of a low power, multiple outputs, isolated DC/DC converter for 100 V telecom satellite applications, using enhancement-mode GaN heterostructure field effect transistors (HFETs) to enable 1 MHz switching frequencies.Radiation-hardened power MOSFETs are currently the main drivers for both cost and size (because of their limited switching frequency) of existing DC/DC converters. Commercially available normally-off GaN HFETs are very promising replacements, thanks to their high switching speed and intrinsic radiation hardness.In this study different designs, built around various isolated topologies, were compared for a typical low power RF application (10W) with a switching frequency of 1 MHz. Calculations and simulations helped select the most adequate architecture in terms of size and efficiency. A prototype was then built and its performance measured. Electromagnetic compatibility was evaluated by mating the power supply to its RF equipment.

  2. SUBCONTRACT REPORT: DC-DC Converter for Fuel Cell and Hybrid Vehicles

    SciTech Connect

    Marlino, Laura D; Zhu, Lizhi

    2007-07-01

    The goal of this project is to develop and fabricate a 5kW dc-dc converter with a baseline 14V output capability for fuel cell and hybrid vehicles. The major objectives for this dc-dc converter technology are to meet: Higher efficiency (92%); High coolant temperature,e capability (105 C); High reliability (15 Years/150,000miles); Smaller volume (5L); Lower weight (6kg); and Lower cost ($75/kW). The key technical challenge for these converters is the 105 C coolant temperatures. The power switches and magnetics must be designed to sustain these operating temperatures reliably, without a large cost/mass/volume penalty.

  3. A Nonlinear Digital Control Solution for a DC/DC Power Converter

    NASA Astrophysics Data System (ADS)

    Zhu, Minshao

    2002-02-01

    A digital Nonlinear Proportional-Integral-Derivative (NPID) control algorithm was proposed to control a 1-kW, PWM, DC/DC, switching power converter. The NPID methodology is introduced and a practical hardware control solution is obtained. The design of the controller was completed using Matlab (trademark) Simulink, while the hardware-in-the-loop testing was performed using both the dSPACE (trademark) rapid prototyping system, and a stand-alone Texas Instruments (trademark) Digital Signal Processor (DSP)-based system. The final Nonlinear digital control algorithm was implemented and tested using the ED408043-1 Westinghouse DC-DC switching power converter. The NPID test results are discussed and compared to the results of a standard Proportional-Integral (PI) controller.

  4. Switched capacitor DC-DC converter ASICs for the upgraded LHC trackers

    NASA Astrophysics Data System (ADS)

    Bochenek, M.; Dabrowski, W.; Faccio, F.; Michelis, S.

    2010-12-01

    The High Luminosity Upgrade of the ATLAS Inner Tracker puts demanding requirements on the powering system of the silicon strip detector modules due to 10-fold increase of the channel count compared to the existing SemiConductor Tracker. Therefore, new solutions for the powering scheme must be elaborated. Currently two possible approaches, the serial powering and the parallel powering scheme using the DC-DC conversion technique, are under development. This paper describes two switched capacitor DC-DC converters designed in a 130 nm technology. For the optimized step-down converter, foreseen for the parallel powering scheme, power efficiency of 97% has been achieved, while for the charge pump, designed for the serial powering scheme, power efficiency of 85% has been achieved.

  5. Design of a Multiple-Input SC DC-DC Converter Realizing Long Battery Runtime

    NASA Astrophysics Data System (ADS)

    Eguchi, Kei; Pongswatd, Sawai; Julsereewong, Amphawan; Tirasesth, Kitti; Sasaki, Hirofumi; Inoue, Takahiro

    A multiple-input switched-capacitor DC-DC converter which can realize long battery runtime is proposed in this letter. Unlike conventional converters for a back-lighting application, the proposed converter drives some LEDs by converting energy from solar cells. Furthermore, the proposed converter can charge a lithium battery when an output load is light. The validity of circuit design is confirmed by theoretical analyses, simulations, and experiments.

  6. Efficiency and weight of voltage multiplier type ultra lightweight dc-dc converters

    NASA Technical Reports Server (NTRS)

    Harrigill, W. T., Jr.; Myers, I. T.

    1975-01-01

    An analytical and experimental study was made of a capacitor-diode voltage multiplier without a transformer which offers the possibility of high efficiency with light weight. The dc-dc conversion efficiencies of about 94 percent were achieved at output powers of 150 watts at 1000 volts using 8x multiplication. A detailed identification of losses was made, including forward drop losses in component, switching losses, reverse junction capacitance charging losses, and charging losses in the main ladder capacitors.

  7. Sliding-mode control of single input multiple output DC-DC converter

    NASA Astrophysics Data System (ADS)

    Zhang, Libo; Sun, Yihan; Luo, Tiejian; Wan, Qiyang

    2016-10-01

    Various voltage levels are required in the vehicle mounted power system. A conventional solution is to utilize an independent multiple output DC-DC converter whose cost is high and control scheme is complicated. In this paper, we design a novel SIMO DC-DC converter with sliding mode controller. The proposed converter can boost the voltage of a low-voltage input power source to a controllable high-voltage DC bus and middle-voltage output terminals, which endow the converter with characteristics of simple structure, low cost, and convenient control. In addition, the sliding mode control (SMC) technique applied in our converter can enhance the performances of a certain SIMO DC-DC converter topology. The high-voltage DC bus can be regarded as the main power source to the high-voltage facility of the vehicle mounted power system, and the middle-voltage output terminals can supply power to the low-voltage equipment on an automobile. In the respect of control algorithm, it is the first time to propose the SMC-PID (Proportion Integration Differentiation) control algorithm, in which the SMC algorithm is utilized and the PID control is attended to the conventional SMC algorithm. The PID control increases the dynamic ability of the SMC algorithm by establishing the corresponding SMC surface and introducing the attached integral of voltage error, which endow the sliding-control system with excellent dynamic performance. At last, we established the MATLAB/SIMULINK simulation model, tested performance of the system, and built the hardware prototype based on Digital Signal Processor (DSP). Results show that the sliding mode control is able to track a required trajectory, which has robustness against the uncertainties and disturbances.

  8. Sliding-mode control of single input multiple output DC-DC converter.

    PubMed

    Zhang, Libo; Sun, Yihan; Luo, Tiejian; Wan, Qiyang

    2016-10-01

    Various voltage levels are required in the vehicle mounted power system. A conventional solution is to utilize an independent multiple output DC-DC converter whose cost is high and control scheme is complicated. In this paper, we design a novel SIMO DC-DC converter with sliding mode controller. The proposed converter can boost the voltage of a low-voltage input power source to a controllable high-voltage DC bus and middle-voltage output terminals, which endow the converter with characteristics of simple structure, low cost, and convenient control. In addition, the sliding mode control (SMC) technique applied in our converter can enhance the performances of a certain SIMO DC-DC converter topology. The high-voltage DC bus can be regarded as the main power source to the high-voltage facility of the vehicle mounted power system, and the middle-voltage output terminals can supply power to the low-voltage equipment on an automobile. In the respect of control algorithm, it is the first time to propose the SMC-PID (Proportion Integration Differentiation) control algorithm, in which the SMC algorithm is utilized and the PID control is attended to the conventional SMC algorithm. The PID control increases the dynamic ability of the SMC algorithm by establishing the corresponding SMC surface and introducing the attached integral of voltage error, which endow the sliding-control system with excellent dynamic performance. At last, we established the MATLAB/SIMULINK simulation model, tested performance of the system, and built the hardware prototype based on Digital Signal Processor (DSP). Results show that the sliding mode control is able to track a required trajectory, which has robustness against the uncertainties and disturbances.

  9. Static DC to DC Power Conditioning-Active Ripple Filter, 1 MHZ DC to DC Conversion, and Nonlinear Analysis. Ph.D. Thesis; [voltage regulation and conversion circuitry for spacecraft power supplies

    NASA Technical Reports Server (NTRS)

    Sander, W. A., III

    1973-01-01

    Dc to dc static power conditioning systems on unmanned spacecraft have as their inputs highly fluctuating dc voltages which they condition to regulated dc voltages. These input voltages may be less than or greater than the desired regulated voltages. The design of two circuits which address specific problems in the design of these power conditioning systems and a nonlinear analysis of one of the circuits are discussed. The first circuit design is for a nondissipative active ripple filter which uses an operational amplifier to amplify and cancel the sensed ripple voltage. A dc to dc converter operating at a switching frequency of 1 MHz is the second circuit discussed. A nonlinear analysis of the type of dc to dc converter utilized in designing the 1 MHz converter is included.

  10. ITAR Free Commercial-of-the-Shelf DC/DC Converter

    NASA Astrophysics Data System (ADS)

    Denzinger, Wolfgang; Hintze, Thomas

    2014-08-01

    A commercial-of-the-shelf (COTS) DC/DC converter for digital space equipment has been developed by ASP under ESA contract with special emphasis on low cost, no use of ITAR listed EEE parts like Mosfets, minimum number of rad-hard digital IC's and a design tolerance against single event effects by appropriate filtering. However, the intention to qualify this discrete converter design for a low cost FM series production was difficult due to the high up-sceening cost of EEE-parts with one lot guarantee and minimum-by. To overcome this problem, in a next step a redesign of the DC/DC converter was performed with all semiconductors like bipolar transistors, rectifiers and zener diodes packaged into hybrids. With this approach it was possible to buy a high number of less expensive wafers or dies from one lot, to perform a lot acceptance test and to integrate the dies into hybrid packages with further up- screening for FM use. The semiconductors have been packaged into three signal hybrids with 44 pins and one power hybrid with 24 pins for the dissipating transistors and rectifiers. The design of the hybrids is such, that all integrated semiconductors can be tested individually. The qualification of four EQM DC/DC converters with different combinations of output voltages has been successfully performed and two FM's have been manufactured and tested.

  11. Materials Testing on the DC-X and DC-XA

    NASA Technical Reports Server (NTRS)

    Smith, Dane; Carroll, Carol; Marschall, Jochen; Pallix, Joan

    1997-01-01

    Flight testing of thermal protection materials has been carried out over a two year period on the base heat shield of the Delta Clipper (DC-X and DC-XA), as well on a body flap. The purpose was to use the vehicle as a test bed for materials and more efficient repair or maintenance processes which would be potentially useful for application on new entry vehicles (i.e., X-33, RLV, planetary probes), as well as on the existing space shuttle orbiters. Panels containing Thermal Protection Systems (TPS) and/or structural materials were constructed either at NASA Ames Research Center or at McDonnell Douglas Aerospace (MDA) and attached between two of the four thrusters in the base heat shield of the DC-X or DC-XA. Three different panels were flown on DC-X flights 6, 7, and 8. A total of 7 panels were flown on DC-XA flights 1, 2, and 3. The panels constructed at Ames contained a variety of ceramic TPS including flexible blankets, tiles with high emissivity coatings, lightweight ceramic ablators and other ceramic composites. The MDS test panels consisted primarily of a variety of metallic composites. This report focuses on the ceramic TPS test results.

  12. Simulation and Performance of Brushless DC Motor Actuators.

    DTIC Science & Technology

    1985-12-01

    AD-RI63 725 SIMULATION AND PERFORMANCE OF IRUSHLESS DC MOTOR ACTUATORS(U) NAVAL POSTGRADUATE SCHOOL MONTEREY CA A GERDA DEC 85 NPS69-85-628 M...California Progress Report SIMULATION AND PERFORMANCE OF BRUSHLESS DC MOTOR ACTUATORS IN SUPPORT OF THE PROGRAM "ADVANCED MISSILE CONTROL DEVICES"I of...34.’ SIMULATION AND PERFORMANCE OF BRUSHLESS DC MOTOR ACTUATORS SUMMARY The simulation model for a Brushless D.C. Motor and the associated * commutation power

  13. 76 FR 52602 - Drawbridge Operation Regulation; Anacostia River, Washington, DC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-23

    ..., Washington, DC AGENCY: Coast Guard, DHS. ACTION: Notice of proposed rulemaking. SUMMARY: The Coast Guard... the Anacostia River, mile 3.4 at Washington, DC. The proposed change will alter the eight hour advance..., SE., Washington, DC 20590-0001. (4) Hand delivery: Same as mail address above, between 9 a.m. and 5...

  14. 76 FR 52566 - Drawbridge Operation Regulations; Anacostia River, Washington, DC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-23

    ... SECURITY Coast Guard 33 CFR Part 117 Drawbridge Operation Regulations; Anacostia River, Washington, DC... Washington, DC. This deviation will test a change to the drawbridge operation schedule to determine whether a..., SE., Washington, DC 20590-0001. (4) Hand delivery: Same as mail address above, between 9 a.m. and 5...

  15. 77 FR 25781 - Environmental Impact Statement; Washington, DC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-01

    ... Federal Highway Administration Environmental Impact Statement; Washington, DC AGENCY: U.S. Federal Highway... Washington, DC is issuing this notice to advise agencies and the public that a Draft Environmental Impact... Avenue Tunnel in Washington, DC. The tunnel is owned and operated by CSX Transportation, Inc. (CSX),...

  16. 77 FR 14968 - Drawbridge Operation Regulation; Anacostia River, Washington, DC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-14

    ..., Washington, DC AGENCY: Coast Guard, DHS. ACTION: Final rule. SUMMARY: The Coast Guard is changing the..., mile 3.4, at Washington, DC. The change will alter the eight hour advance notice requirement for a... Avenue SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except...

  17. Unconventional dc Transport in Rashba Electron Gases.

    PubMed

    Brosco, Valentina; Benfatto, Lara; Cappelluti, Emmanuele; Grimaldi, Claudio

    2016-04-22

    We discuss the transport properties of a disordered two-dimensional electron gas with strong Rashba spin-orbit coupling. We show that in the high-density regime where the Fermi energy overcomes the energy associated with spin-orbit coupling, dc transport is accurately described by a standard Drude's law, due to a nontrivial compensation between the suppression of backscattering and the relativistic correction to the quasiparticle velocity. On the contrary, when the system enters the opposite dominant spin-orbit regime, Drude's paradigm breaks down and the dc conductivity becomes strongly sensitive to the spin-orbit coupling strength, providing a suitable tool to test the entanglement between spin and charge degrees of freedom in these systems.

  18. 75 FR 38017 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-10 Series Airplanes, DC-9-30...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-01

    ... Corporation Model DC- 9-10 Series Airplanes, DC-9-30 Series Airplanes, DC-9-81 (MD-81) Airplanes, DC-9-82 (MD-82) Airplanes, DC-9-83 (MD-83) Airplanes, DC-9- 87 (MD-87) Airplanes, MD-88 Airplanes, and MD-90-30..., Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590. Hand Delivery: U.S. Department...

  19. Engine bleed air reduction in DC-10

    NASA Technical Reports Server (NTRS)

    Newman, W. H.; Viele, M. R.

    1980-01-01

    An 0.8 percent fuel savings was achieved by a reduction in engine bleed air through the use of cabin air recirculation. The recirculation system was evaluated in revenue service on a DC-10. The cabin remained comfortable with reductions in cabin fresh air (engine bleed air) as much as 50 percent. Flight test verified the predicted fuel saving of 0.8 percent.

  20. NASA's DC-8 With Rain Mapping Radar

    NASA Technical Reports Server (NTRS)

    1999-01-01

    In a joint venture between NASA and Japan's NASDA, scientists have been using satellites, airplanes, and boats to measure rain physics in and under thunderstorms over open water. This Quick Time movie shows NASA's DC-8 jet with the instruments like the airborne rain mapping radar, i.e., the Advanced Microwave Precipitation Radiometer (AMPR) and a lightening imaging sensor. Earth science and weather studies are an important ongoing function of NASA and its affiliates.

  1. Static dc voltage stabilizer-converter

    NASA Technical Reports Server (NTRS)

    Osadchiy, V. I.

    1974-01-01

    The advantages are outlined of a static dc voltage converter combining the functions of the feed voltage stabilizer simultaneously. A comparison is made between the circuits for the known static stabilizer converter and that developed by the author. A characteristic feature of the improved system is the increased stabilization coefficient, low output impedance and the possibility of smooth regulation of the output voltage. A practical diagram is presented for the improved high voltage stabilizer converter and its parameters.

  2. Stray current characteristics of DC transit systems

    SciTech Connect

    Moody, K.J. . Transportation Technologies Div.)

    1994-06-01

    The re-emergence and rapid growth of use of DC-powered transit systems around the world has led to the adaptation of three distinct operational modes: grounded, ungrounded, and diode grounded. Each of these modes causes widely varying amounts of stray current in systems using the running rails for negative return current. The advantages of each operational mode and the possible stray current effects on transit and adjacent utility structures are discussed.

  3. DC side filters for multiterminal HVDC systems

    SciTech Connect

    Shore, N.L.; Adamson, K.; Bard, P.

    1996-10-01

    Multiterminal HVDC systems present challenges in the specification and design of suitable dc side filtering. This document examines the existing experience and addresses the particular technical problems posed by multiterminal systems. The filtering requirements of small taps are discussed, as is the potential use of active filters. Aspects of calculation and design are considered and recommendations made to guide the planners and designers of future multiterminal schemes.

  4. DC CHARACTERIZATION OF HIGH GRADIENT MULTILAYER INSULATORS

    SciTech Connect

    Watson, J A; Caporaso, G J; Sampayan, S E; Sanders, D M; Krogh, M L

    2005-05-26

    We have developed a novel insulator concept that involves the use of alternating layers of conductors and insulators with periods less than 1 mm. We have demonstrated that these structures perform 2 to 5 times better than conventional insulators in long pulse, short pulse, and alternating polarity applications. We present new testing results showing exceptional behavior at DC, with gradients in excess of 110kV/cm in vacuum.

  5. Circuit Regulates Speed Of dc Motor

    NASA Technical Reports Server (NTRS)

    Weaver, Charles; Padden, Robin; Brown, Floyd A., Jr.

    1990-01-01

    Driving circuit regulates speed of small dc permanent-magnet motor in tape recorder. Two nested feedback loops maintain speed within 1 percent of constant value. Inner loop provides coarse regulation, while outer loop removes most of variation in speed that remains in the presence of regulation by the inner loop. Compares speed of motor with commanded speed and adjusts current supplied to motor accordingly.

  6. DC-8 Airborne Laboratory in flight

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This 17-second clip shows air-to-air shots of the NASA DC-8 airborne laboratory as it passes over the NASA Dryden Flight Research Center at Edwards, California, and the foothills of the Sierra Nevada mountains. On December 29, 1997, NASA Dryden Flight Research Center, Edwards, California, received a DC-8 airborne laboratory from NASA Ames Research Center, Moffett Field, California, where it had flown missions related to airborne science and earth science for many years. This airplane has continued to be used from Dryden for basic research about the Earth's surface and atmosphere as well as sensor development and satellite sensor verification. In mid-February 1998, the DC-8 resumed flying its medium-altitude, science-gathering missions following maintenance and upgrades of its satellite communications system. It flew a variety of missions over widely scattered geographic regions during the rest of the calendar year and beyond to gather data about earth science, including weather and climate. Built by Douglas Aircraft Company, Long Beach, California, in 1966, the DC-8 flew for 20 years with two major airlines before being acquired by NASA and converted to its present role as an airborne laboratory. The four-engine former jetliner was capable of flying extended-duration missions as long as 12 hours over a range of 5,400 nautical miles at cruise altitudes up to 41,000 feet. It was also capable of carrying a payload of multiple experiments weighing up to 30,000 pounds. On some of its missions, up to 30 scientists have worked on as many as 14 different experiments.

  7. DC-8 airborne laboratory in flight

    NASA Technical Reports Server (NTRS)

    1998-01-01

    In this 26-second clip the NASA DC-8 airborne laboratory is shown making turns over the Sierra Nevada foothills, NASA Dryden Flight Research Center, and Rogers Dry Lakebed at Edwards Air Force Base, California. On December 29, 1997, NASA Dryden Flight Research Center, Edwards, California, received a DC-8 airborne laboratory from NASA Ames Research Center, Moffett Field, California, where it had flown missions related to airborne science and earth science for many years. This airplane has continued to be used from Dryden for basic research about the Earth's surface and atmosphere as well as sensor development and satellite sensor verification. In mid-February 1998, the DC-8 resumed flying its medium-altitude, science-gathering missions following maintenance and upgrades of its satellite communications system. It flew a variety of missions over widely scattered geographic regions during the rest of the calendar year and beyond to gather data about earth science, including weather and climate. Built by Douglas Aircraft Company, Long Beach, California, in 1966, the DC-8 flew for 20 years with two major Airlines before being acquired by NASA and converted to its present role as an airborne laboratory. The four-engine former jetliner was capable of flying extended-duration missions for as long as 12 hours over a range of 5,400 nautical miles at cruise altitudes of up to 41,000 feet. It was also capable of carrying a payload of multiple experiments weighing up to 30,000 pounds. On some of its missions, up to 30 scientists have worked on as many as 14 different experiments.

  8. Performance of 22.4-kW nonlaminated-frame dc series motor with chopper controller. [a dc to dc voltage converter

    NASA Technical Reports Server (NTRS)

    Schwab, J. R.

    1979-01-01

    Performance data obtained through experimental testing of a 22.4 kW traction motor using two types of excitation are presented. Ripple free dc from a motor-generator set for baseline data and pulse width modulated dc as supplied by a battery pack and chopper controller were used for excitation. For the same average values of input voltage and current, the motor power output was independent of the type of excitation. However, at the same speeds, the motor efficiency at low power output (corresponding to low duty cycle of the controller) was 5 to 10 percentage points lower on chopped dc than on ripple free dc. The chopped dc locked-rotor torque was approximately 1 to 3 percent greater than the ripple free dc torque for the same average current.

  9. Estimation of Bidirectional Buck/boost DC/DC Converters with Electric Double-Layer Capacitors for Energy Storage Systems

    NASA Astrophysics Data System (ADS)

    Funabiki, Shigeyuki; Yamamoto, Masayoshi

    Renewable energy such as wind force and solar light has collected the attention as alternative energy sources of fossil fuel. An energy storage system with an electric double-layer capacitor (EDLC), which balances the demand and supply power, is required in order to introduce the electric power generating system that utilizes renewable energy. Currently, the research and development of these energy storage systems are actively carried out. In the energy storage system with an EDLC, the DC/DC converter having the function of the bidirectional power flow and the buck/boost performance is essential as an interface and power control circuit. There are two types of the bidirectional buck/boost DC/DC converters. One type consists of two buck/boost DC/DC converters with one reactor. The other type consists of two sets of two-quadrant DC/DC converters with one reactor. This paper discusses the comparison of these types of DC/DC converters with bidirectional power flow and buck/boost performance. The two types of DC/DC converters are estimated for their application to the energy storage system with the EDLC. As the voltage endurance of the device is lower and the mean current is smaller in the latter type of converter despite of having twice the number of devices compared to the former, the latter type of converter has the advantage of a smaller reactor, i.e., core volume and loss, and lower loss in the converter.

  10. 78 FR 9044 - Adequacy Status of the Motor Vehicle Emission Budgets for Metropolitan Washington DC Area (DC-MD...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-07

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY Adequacy Status of the Motor Vehicle Emission Budgets for Metropolitan Washington DC Area (DC-MD... EPA's finding, the Washington DC-MD-VA Nonattainment Area for the 1997 8-Hour Ozone National...

  11. Development of a smart DC grid model

    NASA Astrophysics Data System (ADS)

    Dalimunthe, Amty Ma'rufah Ardhiyah; Mindara, Jajat Yuda; Panatarani, Camellia; Joni, I. Made

    2016-03-01

    Smart grid and distributed generation should be the solution of the global climate change and the crisis energy of the main source of electrical power generation which is fossil fuel. In order to meet the rising electrical power demand and increasing service quality demands, as well as reduce pollution, the existing power grid infrastructure should be developed into a smart grid and distributed power generation which provide a great opportunity to address issues related to energy efficiency, energy security, power quality and aging infrastructure systems. The conventional of the existing distributed generation system is an AC grid while for a renewable resources requires a DC grid system. This paper explores the model of smart DC grid by introducing a model of smart DC grid with the stable power generation give a minimal and compressed circuitry that can be implemented very cost-effectively with simple components. The PC based application software for controlling was developed to show the condition of the grid and to control the grid become `smart'. The model is then subjected to a severe system perturbation, such as incremental change in loads to test the performance of the system again stability. It is concluded that the system able to detect and controlled the voltage stability which indicating the ability of power system to maintain steady voltage within permissible rangers in normal condition.

  12. CD8α¯ DC is the major DC subset which mediates inhibition of allergic responses by Schistosoma infection.

    PubMed

    Liu, J-Y; Lu, P; Hu, L-Z; Shen, Y-J; Zhu, Y-J; Ren, J-L; Ji, W-H; Zhang, X-Z; Wu, Z-Q; Yang, X-Z; Yang, J; Li, L-Y; Yang, X; Liu, P-M

    2014-12-01

    Our and others' previous studies have shown that Schistosoma japonicum (SJ) infection can inhibit allergic reactions. We recently reported that DCs played an important role in SJ infection-mediated inhibition of allergy, which was associated with enhanced IL-10 and T regulatory cell responses. Here, we further compared the role of CD8α(+) DC and CD8α(-) DC subsets for the inhibitory effect. We sorted CD8α(+) DC (SJCD8α(+) DC) and CD8α(-) DC (SJCD8α(-) DC) from SJ-infected mice and tested their ability to modulate allergic responses in vivo. The data showed that the adoptive transfer of SJCD8α(-) DC was much more efficient than SJCD8α(+) DC for the suppression of allergic airway eosinophilia, mucus overproduction, antigen-specific IgE responses, and Th2 cytokines (IL-4 and IL-5). More importantly, we found that the transfer of SJCD8α(-) DC, but not SJCD8α(+) DC, significantly increased IL-10 and TGF-β production following OVA exposure. As control, the transfer of DC subsets from naïve mice had no significant effect on allergic inflammation. In addition, SJCD8α-DC expressed significantly higher IL-10 but lower IL-12, CD80 and CD86 than SJCD8α(+) DC, fitting a tolerogenic phenotype. The results suggest that CD8α(-) DC is the predominant DC subset which is involved in the parasitic infection-mediated inhibition of allergic inflammation and possibly through enhancing immunomodulatory cytokine (IL-10 and TGF-β) production.

  13. New topology for DC/DC bidirectional converter for hybrid systems in renewable energy

    NASA Astrophysics Data System (ADS)

    Lopez, Juan Carlos; Ortega, Manuel; Jurado, Francisco

    2015-03-01

    This article presents a new isolated DC/DC bidirectional converter with soft switching, using a transformer with two voltage taps and two full bridges with insulated-gate bipolar transistors (IGBTs), one on each side of the transformer to be integrated in hybrid systems of renewable energy. A large voltage conversion ratio can be achieved using this converter, in buck and booster modes. Also medium and high DC power can be converted with a good efficiency. Analysis and switching techniques have been reported. To verify the principle of operation, a laboratory prototype of 10 kW has been performed. Experimental results are presented, operating in boost mode. The switching algorithm used has been modelled in MATLAB-Simulink to generate C code. This code has been implemented in a DSP F2812, which has been used to build the prototype.

  14. Some results regarding stability of photovoltaic maximum-power-point tracking dc-dc converters

    NASA Astrophysics Data System (ADS)

    Schaefer, John F.

    An analytical investigation of a class of photovoltaic (PV) maximum-power-point tracking dc-dc converters has yielded basic results relative to the stability of such devices. Necessary and sufficient conditions for stable operation are derived, and design tools are given. Specific results have been obtained for arbitrary PV arrays driving converters powering resistive loads and batteries. The analytical techniques are applicable to inverters, also. Portions of the theoretical results have been verified in operational devices: a 1500 watt unit has driven a 1-horsepower, 90-volt dc motor powering a water pump jack for over one year. Prior to modification shortly after initial installation, the unit exhibited instability at low levels of irradiance, as predicted by the theory. Two examples are provided.

  15. 75 FR 82333 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, and MD-10-10F...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-30

    ... Corporation Model DC- 10-10, DC-10-10F, and MD-10-10F Airplanes AGENCY: Federal Aviation Administration (FAA... directive (AD) for certain Model DC-10-10, DC-10-10F, and MD-10-10F airplanes. This proposed AD would...., Washington, DC 20590. Hand Delivery: U.S. Department of Transportation, Docket Operations, M-30,...

  16. DC-to-dc converter power-train optimization for maximum efficiency

    NASA Astrophysics Data System (ADS)

    Wilson, T. G., Jr.; Whelan, E. W., Jr.; Rodriguez, R.; Dishman, J. M.

    This paper presents a new way of describing the independent and dependent design variables of the power train of a dc-to-dc converter in terms of a multi-dimensional design-parameter space. These concepts provide a framework for examining the problem of design optimization of the power train, with particular emphasis on the maximization of converter efficiency. Numerous examples of important parameter-space surfaces illustrate some of the major relationships between core volume, switching frequency and output power, and between efficiency, ripple, and temperature rise of the energy-storage reactor. Also, we explore the difference in performance between the continuous and discontinuous mmf modes of operation.

  17. Soft-start mechanism with coefficients Ki optimization for DC-DC power converters

    NASA Astrophysics Data System (ADS)

    Wang, Qian; Hu, Jiajun; Chen, Houpeng; Li, Xi; Fan, Xi; Miao, Jie; Song, Zhitang

    2016-10-01

    This paper presents a fully digital-control soft start mechanism with coefficients Ki optimization for DC-DC power converters. During the soft start phase, a ladder reference voltage steps up gradually to make inductor current ramp up smoothly and overshoot voltage is minimized with the proposed coefficients Ki distribution. Simulation results show that massive inductor current can be well avoided during the soft start process with the proposed soft start mechanism, which only occupies a chip area of 300um×120um.

  18. A High Power Density DC-DC Converter for Distributed PV Architectures

    SciTech Connect

    Agamy, Mohammed S; Chi, Song; Elasser, Ahmed; Harfman-Todorovic, Maja; Jiang, Yan; Mueller, Frank; Tao, Fengfeng

    2012-06-01

    In order to maximize solar energy harvesting capabilities, power converters have to be designed for high efficiency and good MPPT and voltage/current performance. When many converters are used in distributed systems, power density also becomes an important factor as it allows for simpler system integration. In this paper a high power density string dc-dc converter suitable for distributed medium to large scale PV installation is presented. A simple partial power processing topology, implemented with all silicon carbide devices provides high efficiency as well as high power density. A 3.5kW, 100kHz converter is designed and tested to verify the proposed methods.

  19. A New Approach for High Efficiency Buck-Boost DC/DC Converters Using Series Compensation

    NASA Astrophysics Data System (ADS)

    Itoh, Jun-Ichi; Fujii, Takashi

    This paper proposes a novel concept for non-isolated buck-boost DC/DC converter and control method. The proposed concept uses a series connection converter that only regulates the differential voltage between the input and output voltage. As a result, the power converter capacity is decreased. Moreover, the proposed circuit has advantages such as improved efficiency and losses reduction. The fundamental operation, control method, and design method of the proposed circuit are described in this paper. In addition, the validity of the proposed circuit is confirmed by carrying out simulations and experiments.

  20. Real-Time Implementation of a Fuzzy Logic Controller for DC-DC Switching Converters

    DTIC Science & Technology

    2007-11-02

    studies, it will be observed that, the proposed fuzzy controller maintains the output voltage at the desired 5V with slight overshoot during each...537-546, May 1997. [3] H. Sira -Ramirez, “Design of P-I controllers for DC-to-DC power supplies via extended linearization,” Int. J. Control, vol. 51...Technology, vol. 7, pp. 230-237, Mar. 1999. [5] G. Escobar, R. Ortega, H. Sira -Ramirez, J.P. Vilain and I. Zein, “An experimental comparison of several

  1. DC-DC Converter Topology Assessment for Large Scale Distributed Photovoltaic Plant Architectures

    SciTech Connect

    Agamy, Mohammed S; Harfman-Todorovic, Maja; Elasser, Ahmed; Sabate, Juan A; Steigerwald, Robert L; Jiang, Yan; Essakiappan, Somasundaram

    2011-07-01

    Distributed photovoltaic (PV) plant architectures are emerging as a replacement for the classical central inverter based systems. However, power converters of smaller ratings may have a negative impact on system efficiency, reliability and cost. Therefore, it is necessary to design converters with very high efficiency and simpler topologies in order not to offset the benefits gained by using distributed PV systems. In this paper an evaluation of the selection criteria for dc-dc converters for distributed PV systems is performed; this evaluation includes efficiency, simplicity of design, reliability and cost. Based on this evaluation, recommendations can be made as to which class of converters is best fit for this application.

  2. CMOS-Compatible SOI MESFETS for Radiation-Hardened DC-to-DC Converters

    NASA Technical Reports Server (NTRS)

    Thornton, Trevor; Lepkowski, William; Wilk, Seth

    2013-01-01

    A radiation-tolerant transistor switch has been developed that can operate between 196 and +150 C for DC-to-DC power conversion applications. A prototype buck regulator component was demonstrated to be performing well after a total ionizing dose of 300 krad(Si). The prototype buck converters showed good efficiencies at ultra-high switching speeds in the range of 1 to 10 MHz. Such high switching frequency will enable smaller, lighter buck converters to be developed as part of the next project. Switching regulators are widely used in commercial applications including portable consumer electronics.

  3. Finite-time control of DC-DC buck converters via integral terminal sliding modes

    NASA Astrophysics Data System (ADS)

    Chiu, Chian-Song; Shen, Chih-Teng

    2012-05-01

    This article presents novel terminal sliding modes for finite-time output tracking control of DC-DC buck converters. Instead of using traditional singular terminal sliding mode, two integral terminal sliding modes are introduced for robust output voltage tracking of uncertain buck converters. Different from traditional sliding mode control (SMC), the proposed controller assures finite convergence time for the tracking error and integral tracking error. Furthermore, the singular problem in traditional terminal SMC is removed from this article. When considering worse modelling, adaptive integral terminal SMC is derived to guarantee finite-time convergence under more relaxed stability conditions. In addition, several experiments show better start-up performance and robustness.

  4. Research on transient hysteresis current control strategy of DC-DC converter

    NASA Astrophysics Data System (ADS)

    Zhang, Ting; Wang, Zu-liang; Zhao, Yu-kai

    2017-01-01

    In order to improve the dynamic performance of DC-DC converter, transient hysteresis current control strategy is proposed which is based on parallel computing and combinational logic. By making a comparison between the real-time inductor current and the threshold inductor current, the switch is controlled more accurately. Under the Matlab/Simulink environment, the process of the Buck-Boost converter was simulated. The simulation results show that the transient hysteresis current control strategy can effectively overcome the disadvantages when load changes or input voltage disturbance occurs, it posses high load regulation and short dynamic response time, and it verifies the feasibility of the proposed strategy.

  5. Improved DC Gun and Insulator Assembly

    SciTech Connect

    Neubauer, Michael

    2015-01-11

    Many user facilities such as synchrotron radiation light sources and free electron lasers rely on DC high voltage photoguns with internal field gradients as high as 10 to 15 MV/m. These high gradients often lead to field emission which poses serious problems for the photocathode used to generate the electron beam and the ceramic insulators used to bias the photocathode at high voltage. Ceramic insulators are difficult to manufacture, require long commissioning times, and have poor reliability, in part because energetic electrons bury themselves in the ceramic causing a buildup of charge and eventual puncture, and also because large diameter ceramics are difficult to braze reliably. The lifetimes of photo cathodes inside high current DC guns exhibiting field emission are limited to less than a hundred hours. Reducing the surface gradients on the metals reduces the field emission, which serves to maintain the required ultrahigh vacuum condition. A novel gun design with gradients around 5 MV/m and operating at 350 kV, a major improvement over existing designs, was proposed that allows for the in-situ replacement of photo cathodes in axially symmetric designs using inverted ceramics. In this project, the existing JLAB CEBAF asymmetric gun design with an inverted ceramic support was modeled and the beam dynamics characterized. An improved structure was designed that reduces the surface gradients and improves the beam optics. To minimize the surface gradients, a number of electrostatic gun designs were studied to determine the optimum configuration of the critical electrodes within the gun structure. Coating experiments were carried out to create a charge dissipative coating for cylindrical ceramics. The phase II proposal, which was not granted, included the design and fabrication of an axially symmetric DC Gun with an inverted ceramic that would operate with less than 5 MV/m at 350 kV and would be designed with an in-situ replaceable photo-cathode.

  6. Two-position dc pulse voltage stabilizer

    NASA Technical Reports Server (NTRS)

    Osadchiy, V. I.

    1974-01-01

    The advantages of the dc pulse voltage stabilizers over the continuous action stabilizers are described. These advantages include higher efficiency, low sensitivity to the ambient temperature and insignificant size and weight. A comparison is made between the schematics of the known two position pulse stabilizer with a Schmitt trigger and that developed by the author. A characteristic feature of the improved system is the increased stabilization coefficient and the possibility of smooth regulation of the output voltage. A practical schematic is presented for the improved two position pulse stabilizer along with its parameters.

  7. CVD diamond growth by dc plasma torch

    NASA Astrophysics Data System (ADS)

    Klocek, Paul; Hoggins, James T.; Taborek, Peter; McKenna, Tom A.

    1990-12-01

    A dc arc discharge plasma torch has been developed for chemical vapor deposition (CVD) diamond growth. The apparatus and process parameters are described. Free-standing polycrystalline diamond samples of 50 mm by 50 mm by a few mm have been grown at high rates. The Raman spectra of the samples show little nondiamond structure. Transmission electron microscopy indicates that the diamond is highly twinned and has a high defect concentration. The infrared spectra indicate the presence of hydrogen contamination in the diamond via absorption bands associated with carbon-hydrogen motion. 2.

  8. Fun D.C. Jobs for Physicists

    SciTech Connect

    Clark Cully

    2009-09-30

    Physicists make valuable contributions in a wide variety of careers, including those in Washington. Many national challenges, including energy, innovation, and security, create a demand for technically-competent individuals across government. Clark will discuss some of the many programs in D.C. designed to attract the best and brightest minds, from grad-students to professors, from short-term assignments to whole new careers. These are great opportunities to use your expertise and enrich your knowledge of the broader scientific enterprise, all while serving society.

  9. Modelling of dc characteristics for granular semiconductors

    NASA Astrophysics Data System (ADS)

    Varpula, Aapo; Sinkkonen, Juha; Novikov, Sergey

    2010-11-01

    The dc characteristics of granular n-type semiconductors are calculated analytically with the drift-diffusion theory. Electronic trapping at the grain boundaries (GBs) is taken into account. The use of quadratic and linear GB potential profiles in the calculation is compared. The analytical model is verified with numerical simulation performed by SILVACO ATLAS. The agreement between the analytical and numerical results is excellent in a large voltage range. The results show that electronic trapping at the GBs has a remarkable effect on the highly nonlinear I-V characteristics of the material.

  10. Preparing to pass the DC test.

    PubMed

    Rogers, A

    Andrew Rogers discusses the high anxiety levels and high failure rates among those sitting the DC test for entry into nurse education. He goes on to describe a preparatory course developed at one school of nursing which aims to provide an early opportunity for candidates to discuss issues relating to nurse training. A mock test allows individuals to receive guidance on their exam performance and to lessen the degree of anxiety which the test itself can generate. Success rates rose among those who followed the preparatory course.

  11. Tunable graphene dc superconducting quantum interference device.

    PubMed

    Girit, Caglar; Bouchiat, V; Naaman, O; Zhang, Y; Crommie, M F; Zettl, A; Siddiqi, I

    2009-01-01

    Graphene exhibits unique electrical properties on account of its reduced dimensionality and "relativistic" band structure. When contacted with two superconducting electrodes, graphene can support Cooper pair transport, resulting in the well-known Josephson effect. We report here the fabrication and operation of a two junction dc superconducting quantum interference device (SQUID) formed by a single graphene sheet contacted with aluminum/palladium electrodes in the geometry of a loop. The supercurrent in this device can be modulated not only via an electrostatic gate but also by an applied magnetic fielda potentially powerful probe of electronic transport in graphene and an ultrasensitive platform for nanomagnetometry.

  12. A dc Penning Surface-Plasma Source

    DTIC Science & Technology

    2007-11-02

    LA-UR-93-2990 Title: A dc Penning Surface-Plasma Source Author(s): Submitted to: H. Vernon Smith, Jr., Paul Allison, Carl Geisik, David R...Type: HC Number of Copies In Library: 000001 Record ID: 28620 A de Penning Surface-Plasma Source* H. Vernon Smith, Jr., Paul Allison, Carl Geisik...Schechter, J. H. Whealton, and J. J. Donaghy, ATP Conf. Proc. No. 158, 366 (1987). 8) H. V. Smith, Jr., N. M. Schnurr, D. H. Whitaker , and K. E. Kalash

  13. Classification of electrical discharges in DC Accelerators

    NASA Astrophysics Data System (ADS)

    Banerjee, Srutarshi; Deb, A. K.; Rajan, Rehim N.; Kishore, N. K.

    2016-08-01

    Controlled electrical discharge aids in conditioning of the system while uncontrolled discharges damage its electronic components. DC Accelerator being a high voltage system is no exception. It is useful to classify electrical discharges according to the severity. Experimental prototypes of the accelerator discharges are developed. Photomultiplier Tubes (PMTs) are used to detect the signals from these discharges. Time and Frequency domain characteristics of the detected discharges are used to extract features. Machine Learning approaches like Fuzzy Logic, Neural Network and Least Squares Support Vector Machine (LSSVM) are employed to classify the discharges. This aids in detecting the severity of the discharges.

  14. Distinct usage of three C-type lectins by Japanese encephalitis virus: DC-SIGN, DC-SIGNR, and LSECtin.

    PubMed

    Shimojima, Masayuki; Takenouchi, Atsushi; Shimoda, Hiroshi; Kimura, Naho; Maeda, Ken

    2014-08-01

    Infection with West Nile virus and dengue virus, two mosquito-borne flaviviruses, is enhanced by two calcium-dependent lectins: dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN), and its related molecule (DC-SIGNR). The present study examined the relationship between Japanese encephalitis virus (JEV) infection and three lectins: DC-SIGN, DC-SIGNR, and liver sinusoidal endothelial cell lectin (LSECtin). Expression of DC-SIGNR resulted in robust JEV proliferation in a lymphoid cell line, Daudi cells, which was otherwise non-permissive to infection. DC-SIGN expression caused moderate JEV proliferation, with effects that varied according to the cells in which JEV was prepared. LSECtin expression had comparatively minor, but consistent, effects, in all cell types used in JEV preparation. While DC-SIGN/DC-SIGNR-mediated JEV infection was inhibited by yeast mannan, LSECtin-mediated infection was inhibited by N-acetylglucosamine β1-2 mannose. Although involvement of DC-SIGN/DC-SIGNR in infection seems to be a common characteristic, this is the first report on usage of LSECtin in mosquito-borne flavivirus infection.

  15. Model Based Optimization of Integrated Low Voltage DC-DC Converter for Energy Harvesting Applications

    NASA Astrophysics Data System (ADS)

    Jayaweera, H. M. P. C.; Muhtaroğlu, Ali

    2016-11-01

    A novel model based methodology is presented to determine optimal device parameters for the fully integrated ultra low voltage DC-DC converter for energy harvesting applications. The proposed model feasibly contributes to determine the maximum efficient number of charge pump stages to fulfill the voltage requirement of the energy harvester application. The proposed DC-DC converter based power consumption model enables the analytical derivation of the charge pump efficiency when utilized simultaneously with the known LC tank oscillator behavior under resonant conditions, and voltage step up characteristics of the cross-coupled charge pump topology. The verification of the model has been done using a circuit simulator. The optimized system through the established model achieves more than 40% maximum efficiency yielding 0.45 V output with single stage, 0.75 V output with two stages, and 0.9 V with three stages for 2.5 kΩ, 3.5 kΩ and 5 kΩ loads respectively using 0.2 V input.

  16. An Integrated Programmable Wide-range PLL for Switching Synchronization in Isolated DC-DC Converters

    NASA Astrophysics Data System (ADS)

    Fard, Miad

    In this thesis, two Phase-Locked-Loop (PLL) based synchronization schemes are introduced and applied to a bi-directional Dual-Active-Bridge (DAB) dc-dc converter with an input voltage up to 80 V switching in the range of 250 kHz to 1 MHz. The two schemes synchronize gating signals across an isolated boundary without the need for an isolator per transistor. The Power Transformer Sensing (PTS) method utilizes the DAB power transformer to indirectly sense switching on the secondary side of the boundary, while the Digital Isolator Sensing (DIS) method utilizes a miniature transformer for synchronization and communication at up to 100 MHz. The PLL is implemented on-chip, and is used to control an external DAB power-stage. This work will lead to lower cost, high-frequency isolated dc-dc converters needed for a wide variety of emerging low power applications where isolator cost is relatively high and there is a demand for the reduction of parts.

  17. Static and Dynamic Characteristics of DC-DC Converter Using a Digital Filter

    NASA Astrophysics Data System (ADS)

    Kurokawa, Fujio; Okamatsu, Masashi

    This paper presents the regulation and dynamic characteristics of the dc-dc converter with digital PID control, the minimum phase FIR filter or the IIR filter, and then the design criterion to improve the dynamic characteristics is discussed. As a result, it is clarified that the DC-DC converter using the IIR filter method has superior performance characteristics. The regulation range is within 1.3%, the undershoot against the step change of the load is less than 2% and the transient time is less than 0.4ms with the IIR filter method. In this case, the switching frequency is 100kHz and the step change of the load R is from 50 Ω to 10 Ω. Further, the superior characteristics are obtained when the first gain, the second gain and the second cut-off frequency are relatively large, and the first cut-off frequency and the passing frequency are relatively low. Moreover, it is important that the gain strongly decreases at the second cut-off frequency because the upper band pass frequency range must be always less than half of the sampling frequency based on the sampling theory.

  18. Bifurcation Analysis of a DC-DC Bidirectional Power Converter Operating with Constant Power Loads

    NASA Astrophysics Data System (ADS)

    Cristiano, Rony; Pagano, Daniel J.; Benadero, Luis; Ponce, Enrique

    Direct current (DC) microgrids (MGs) are an emergent option to satisfy new demands for power quality and integration of renewable resources in electrical distribution systems. This work addresses the large-signal stability analysis of a DC-DC bidirectional converter (DBC) connected to a storage device in an islanding MG. This converter is responsible for controlling the balance of power (load demand and generation) under constant power loads (CPLs). In order to control the DC bus voltage through a DBC, we propose a robust sliding mode control (SMC) based on a washout filter. Dynamical systems techniques are exploited to assess the quality of this switching control strategy. In this sense, a bifurcation analysis is performed to study the nonlinear stability of a reduced model of this system. The appearance of different bifurcations when load parameters and control gains are changed is studied in detail. In the specific case of Teixeira Singularity (TS) bifurcation, some experimental results are provided, confirming the mathematical predictions. Both a deeper insight in the dynamic behavior of the controlled system and valuable design criteria are obtained.

  19. Light weight, high power, high voltage dc/dc converter technologies

    NASA Technical Reports Server (NTRS)

    Kraus, Robert; Myers, Ira; Baumann, Eric

    1990-01-01

    Power-conditioning weight reductions by orders of magnitude will be required to enable the megawatt-power-level space systems envisioned by the Strategic Defense Initiative, the Air Force, and NASA. An interagency program has been initiated to develop an 0.1-kg/kW dc/dc converter technology base for these future space applications. Three contractors are in the first phase of a competitive program to develop a megawatt dc/dc converter. Researchers at NASA Lewis Research Center are investigating innovative converter topology control. Three different converter subsystems based on square wave, resonant, and super-resonant topologies are being designed. The components required for the converter designs cover a wide array of technologies. Two different switches, one semiconductor and the other gas, are under development. Issues related to thermal management and material reliability for inductors, transformers, and capacitors are being investigated in order to maximize power density. A brief description of each of the concepts proposed to meet the goals of this program is presented.

  20. Thermoelectric-Generator-Based DC-DC Conversion Networks for Automotive Applications

    NASA Astrophysics Data System (ADS)

    Li, Molan; Xu, Shaohui; Chen, Qiang; Zheng, Li-Rong

    2011-05-01

    Maximizing electrical energy generation through waste heat recovery is one of the modern research questions within automotive applications of thermoelectric (TE) technologies. This paper proposes a novel concept of distributed multisection multilevel DC-DC conversion networks based on thermoelectric generators (TEGs) for automotive applications. The concept incorporates a bottom-up design approach to collect, convert, and manage vehicle waste heat efficiently. Several state-of-the-art thermoelectric materials are analyzed for the purpose of power generation at each waste heat harvesting location on a vehicle. Optimal materials and TE couple configurations are suggested. Moreover, a comparison of prevailing DC-DC conversion techniques was made with respect to applications at each conversion level within the network. Furthermore, higher-level design considerations are discussed according to system specifications. Finally, a case study is performed to compare the performance of the proposed network and a traditional single-stage system. The results show that the proposed network enhances the system conversion efficiency by up to 400%.

  1. Hybrid DC/DC Converter for SAR Antenna Power Supply Unit

    NASA Astrophysics Data System (ADS)

    Calcatterra, Paolo; Galantini, Paolo; Scorzafava, Edmondo; Sagnelli, Salvatore; Benettin, Piero

    2014-08-01

    When distributed power supply is mandatory to provide full functional redundancy in a SAR application, a compact design to minimize size and weight became the main driver of the system.In this context a single hermetic DC/DC converter, including magnetic components, has been made in thick-film Hybrid technology.It is designed for state of the art electrical performance, minimum mass and size, maximum reliability for SAR application, where each transmitter / receiver module is powered by one dedicated DC/DC converterIt is characterised by a very simplified design approach to get high reliability and repeatability for large scale production.The Hybrid uses a standard thick film multilayer technology, currently in use for military and Space application.A few passive components are placed outside the Hybrid according to desired Conducted Emission / Susceptibility performance requirements (input and output filters).The Hybrid is manufactured with multilayer ceramic substrate with ad-hoc solution to manage thermal and cross talk signal issues.The trimming of the PSU is via laser active trimming performed during Hybrid manufacturing. No further trimming is needed.The process control is performed according to MIL PRF 38534.The Hybrid is manufactured according ECSS-Q-ST-60- 05C.

  2. Prediction of radiated emissions from DC motors

    NASA Astrophysics Data System (ADS)

    Suriano, Candace Rogers

    DC motors are known sources of radio frequency electromagnetic noise produced by arcing at the motor brushes. A simplified model of electromagnetic radiation from a DC motor and associated wiring harness is desired to guide engineers in the design process. Of particular interest is their behavior at low frequencies in a reverberation chamber. Different methods are used to devise a voltage transfer function between a device under test (DUT) and a monopole antenna for near field low frequency testing in a reverberation chamber. A simple scaling factor is used to transform low frequency monopole antenna data between different reverberation chamber configurations. Further refinement in the modeling is based on common mode current. Test data indicated that a simple equivalent RLC circuit could represent the common mode current. The validity of the approach is shown using the Electric Field Integral Equation. Various quasi-static and static models were used to compute the circuit parameters. Furthermore, a second circuit was shown to relate the common mode current to the receiving antenna voltage. Moment method models and test data demonstrate this relationship.

  3. Simulation of the dc Plasma in Carbon Nanotube Growth

    NASA Technical Reports Server (NTRS)

    Hash, David; Bose, Deepak; Govindan, T. R.; Meyyappan, M.; Biegel, Bryan (Technical Monitor)

    2003-01-01

    A model for the dc plasma used in carbon nanotube growth is presented, and one-dimensional simulations of an acetylene/ammonia/argon system are performed. The effect of dc bias is illustrated by examining electron temperature, electron and ion densities, and neutral densities. Introducing a tungsten filament in the dc plasma, as in hot filament chemical vapor deposition with plasma assistance, shows negligible influence on the system characteristics.

  4. Variable Rail Voltage Control of a Brushless DC (BLDC) Motor

    DTIC Science & Technology

    2013-01-01

    Variable Rail Voltage Control of a Brushless DC ( BLDC ) Motor by Yuan Chen, Joseph Conroy, and William Nothwang ARL-TR-6308 January 2013...TR-6308 January 2013 Variable Rail Voltage Control of a Brushless DC ( BLDC ) Motor Yuan Chen, Joseph Conroy, and William Nothwang Sensors...DATES COVERED (From - To) 4. TITLE AND SUBTITLE Variable Rail Voltage Control of a Brushless DC ( BLDC ) Motor 5a. CONTRACT NUMBER 5b. GRANT

  5. Obtaining DC and AC isothermal electrical characteristics for RF MOSFET

    NASA Astrophysics Data System (ADS)

    Sahoo, A. K.; Fregonese, S.; Scheer, P.; Celi, D.; Juge, A.; Zimmer, T.

    2015-04-01

    In this paper we demonstrate a new and simple approach to obtain isothermal electrical characteristics of metal oxide field effect transistor (MOSFET) from conventional non-isothermal measurements. DC and continuous wave (CW) S-parameter measurements are performed at different chuck temperatures (Tchuck). Knowing the thermal resistance (RTH) of the device the variation of DC and AC characteristic due to self-heating can be de-embedded and all the isothermal DC data and AC data above isothermal frequency can be determined. The method is validated by comparing the results with pulsed DC and pulsed RF measurements and found to be in good agreements.

  6. Photo Gallery for Anacostia Watershed (Washington, DC/Maryland)

    EPA Pesticide Factsheets

    Anacostia Watershed (Washington, DC/Maryland) of the Urban Waters Federal Partnership (UWFP) reconnects urban communities with their waterways by improving coordination among federal agencies and collaborating

  7. Human DC-SIGN Binds Specific Human Milk Glycans

    PubMed Central

    Noll, Alexander J.; Yu, Ying; Lasanajak, Yi; Duska-McEwen, Geralyn; Buck, Rachael H.; Smith, David F.; Cummings, Richard D.

    2016-01-01

    Human milk glycans (HMGs) are prebiotics, pathogen receptor decoys, and regulators of host physiology and immune responses. Mechanistically, human lectins (glycan-binding proteins, hGBPs) expressed by dendritic cells (DC) are of major interest, as these cells directly contact HMGs. To explore such interactions, we screened many C-type lectins and Siglecs expressed by DC for glycan binding on microarrays presenting over 200 HMGs. Unexpectedly, DC-SIGN showed robust binding to many HMGs, whereas other C-type lectins failed to bind, and Siglecs-5 and -9 showed weak binding to a few glycans. By contrast, most hGBPs bound to multiple glycans on other microarrays lacking HMGs. An α-linked fucose residue was characteristic of HMGs bound by DC-SIGN. Binding of DC-SIGN to the simple HMGs 2′-fucosyllactose (2′-FL) and 3-fucosyllactose (3-FL) was confirmed by flow cytometry to beads conjugated with 2′-FL or 3-FL, as well as the ability of the free glycans to inhibit DC-SIGN binding. 2′-FL had an IC50 of ~1 mM for DC-SIGN, which is within the physiological concentration of 2′-FL in human milk. These results demonstrate that DC-SIGN among the many hGBPs expressed by DC binds to α-fucosylated HMGs, and suggest that such interactions may be important in influencing immune responses in the developing infant. PMID:26976925

  8. DC to DC Converter Testing for Space Applications: Use of EMI Filters and Thermal Range of Operation

    NASA Technical Reports Server (NTRS)

    Leon, Rosa

    2008-01-01

    Several tests were performed on Interpoint and International Rectifier (IR) direct current (DC) to DC converters to evaluate potential performance and reliability issues in space use of DC to DC converters and to determine if the use of electromagnetic interference (EMI) filters mitigates concerns observed during previous tests. Test findings reported here include those done up until September - October 2008. Tests performed include efficiency, regulation, cross-regulation, power consumption with inhibit on, load transient response, synchronization, and turn-on tests. Some of the test results presented here span the thermal range -55 C to 125 C. Lower range was extended to -120 C in some tested converters. Determination of failure root cause in DC/DC converters that failed at thermal extremes is also included.

  9. Universality of DC electrical conductivity from holography

    NASA Astrophysics Data System (ADS)

    Ge, Xian-Hui; Sin, Sang-Jin; Wu, Shao-Feng

    2017-04-01

    We propose a universal formula of dc electrical conductivity in rotational- and translational-symmetries breaking systems via the holographic duality. This formula states that the ratio of the determinant of the dc electrical conductivities along any spatial directions to the black hole area density in zero-charge limit has a universal value. As explicit illustrations, we give several examples elucidating the validation of this formula: We construct an anisotropic black brane solution, which yields linear in temperature for the in-plane resistivity and insulating behavior for the out-of-plane resistivity; We also construct a spatially isotropic black brane solution that both the linear-T and quadratic-T contributions to the resistivity can be realized. 1). For Z (ϕ) = 1 and d ≥ 3, isotropic black branes in the AdS space cannot be utilized to realize linear temperature resistivity in the zero-charges limit. Nevertheless, anisotropic black branes are good candidates in model-building of holographic strange metals. 2). For d + 1-dimensional spatially isotropic Lifshitz black holes with Z (ϕ) = 1 in the absence of hyperscaling violation, this relation indicates that σii|qi=0 =[ 4 π / (d + z - 1) ] d - 3T (d - 3) / z, which is consistent with what obtained in Refs. [23,24] based on a universal scaling relation hypothesis: σ (ω = 0) =T (d - 3) / z Θ (0), where z is a dynamical critical exponent and Θ (ω) is a frequency dependent function. 3). This relation applies to shear viscosity-bound and electrical conductivity-bound violated systems, for example, systems considered in [20,25,26]. In [27], the authors conjectured that for the case d = 3, there exists a lower bound of dc electrical conductivity ∏iσii > 1. But it was soon found that this bound can be violated by a special coupling between the linear axion fields and the U (1) gauge field [25,26]. The structure of this paper is organized as follows. In section 2, we present our main results by writing

  10. Association of DC-SIGN and DC-SIGNR Repeat Regions with Susceptibility to Pulmonary Tuberculosis in Zahedan, Southeastern Iran.

    PubMed

    Naderi, Mohammad; Hashemi, Mohammad; Soroush, Navid; Amininia, Shadi; Taheri, Mohsen

    2016-05-01

    There are conflicting results concerning DC-SIGN and DC-SIGNR VNTR polymorphisms. The present study aimed to evaluate the possible association between DC-SIGN as well as DC-SIGNR VNTR polymorphisms and pulmonary tuberculosis (PTB) in a sample of Iranian population. This case-control study was done on 171 PTB and 161 healthy subjects. The variants were detected by polymerase chain reaction (PCR). DC-SIGNR VNTR genotypes in cases were 12.7% for 5/5, 2.4% for 6/5, 32.7% for 7/7, 38.2% for 7/5, 5.5% for 7/6, 1.2% for /5, 0.6% for 9/6, 6.7% for 9/7 in PTB patients and 19.7% for 5/5, 2.0% for 6/5, 31.6% for 7/7, 37.5% for 7/5, 5.7% for 7/6, 0.0% for 9/5, 0.7% for 9/6, 2.6% for 9/7 in controls. The findings showed no significant association between DC-SIGNR VNTR polymorphism and PTB. All subjects in cases and controls were 7/7 genotype regarding DC-SIGN VNTR polymorphism. Our data propose that DC-SIGNR VNTR, as well as DC-SIGN VNTR, were not associated with the risk of PTB in a sample of Iranian population.

  11. Dissipative cryogenic filters with zero dc resistance.

    PubMed

    Bluhm, Hendrik; Moler, Kathryn A

    2008-01-01

    The authors designed, implemented, and tested cryogenic rf filters with zero dc resistance, based on wires with a superconducting core inside a resistive sheath. The superconducting core allows low frequency currents to pass with negligible dissipation. Signals above the cutoff frequency are dissipated in the resistive part due to their small skin depth. The filters consist of twisted wire pairs shielded with copper tape. Above approximately 1 GHz, the attenuation is exponential in omega, as typical for skin depth based rf filters. By using additional capacitors of 10 nF per line, an attenuation of at least 45 dB above 10 MHz can be obtained. Thus, one single filter stage kept at mixing chamber temperature in a dilution refrigerator is sufficient to attenuate room temperature black body radiation to levels corresponding to 10 mK above about 10 MHz.

  12. Counterrotating brushless DC permanent magnet motor

    NASA Astrophysics Data System (ADS)

    Hawsey, R. A.; Bailey, J. M.

    1990-07-01

    A brushless DC permanent magnet motor is provided for driving an autonomous underwater vehicle. In one embodiment, the motor comprises four substantially flat stators disposed in stacked relationship, with pairs of the stators being axially spaced and each of the stators comprising a tape-wound stator coil; first and second substantially flat rotors disposed between the spaced pairs of stators. Each of the rotors includes an annular array of embedded permanent magnets. A first shaft is connected to the first rotor and a second, concentric shaft is connected to the second rotor, and the drive unit causes rotation of the two shafts in opposite directions. The second shaft comprises a hollow tube having a central bore in which the first shaft is disposed. Two different sets of bearings support the first and second shafts. In another embodiment, the motor comprises two ironless stators and pairs, and rotors mounted on opposite sides of the stators and driven by counterrotating shafts.

  13. Generalized model of brushless dc generator

    NASA Astrophysics Data System (ADS)

    Vadher, V. V.; Kettleborough, J. Gordon; Smith, I. R.; Gerges, Wahid R.

    1989-07-01

    A generalized model is described for a brushless dc machine consisting of a multiphase synchronous machine with a full-wave bridge rectifier connected to its output terminals. The state-variable equations for the machine are suitable for numerical integration on a digital computer, and are assembled in a form which permits investigations to be made on the effects of different numbers of armature phase windings and different winding connections. The model has been used in both steady-state and transient studies on a number of generating units, with the detailed information which is provided being beneficial to design engineers. Comparisons presented between predicted and measured results illustrate the validity of the model and the mathematical techniques adopted, and confirm that accurate information on the performance of a brushless generator may be obtained prior to manufacture.

  14. Electronically commutated dc motors for electric vehicles

    NASA Technical Reports Server (NTRS)

    Maslowski, E. A.

    1981-01-01

    A motor development program to explore the feasibility of electronically commutated dc motors (also known as brushless) for electric cars is described. Two different design concepts and a number of design variations based on these concepts are discussed. One design concept is based on a permanent magnet, medium speed, machine rated at 7000 to 9000 rpm, and powered via a transistor inverter power conditioner. The other concept is based on a permanent magnet, high speed, machine rated at 22,000 to 26,000 rpm, and powered via a thyristor inverter power conditioner. Test results are presented for a medium speed motor and a high speed motor each of which have been fabricated using samarium cobalt permanent magnet material.

  15. Dissipative Cryogenic Filters with Zero DC Resistance

    SciTech Connect

    Bluhm, Hendrik; Moler, Kathryn A.; /Stanford U., Appl. Phys. Dept

    2008-04-22

    The authors designed, implemented and tested cryogenic RF filters with zero DC resistance, based on wires with a superconducting core inside a resistive sheath. The superconducting core allows low frequency currents to pass with negligible dissipation. Signals above the cutoff frequency are dissipated in the resistive part due to their small skin depth. The filters consist of twisted wire pairs shielded with copper tape. Above approximately 1 GHz, the attenuation is exponential in {radical}{omega}, as typical for skin depth based RF filters. By using additional capacitors of 10 nF per line, an attenuation of at least 45 dB above 10 MHz can be obtained. Thus, one single filter stage kept at mixing chamber temperature in a dilution refrigerator is sufficient to attenuate room temperature black body radiation to levels corresponding to 10 mK above about 10 MHz.

  16. Electronically commutated dc motors for electric vehicles

    NASA Astrophysics Data System (ADS)

    Maslowski, E. A.

    A motor development program to explore the feasibility of electronically commutated dc motors (also known as brushless) for electric cars is described. Two different design concepts and a number of design variations based on these concepts are discussed. One design concept is based on a permanent magnet, medium speed, machine rated at 7000 to 9000 rpm, and powered via a transistor inverter power conditioner. The other concept is based on a permanent magnet, high speed, machine rated at 22,000 to 26,000 rpm, and powered via a thyristor inverter power conditioner. Test results are presented for a medium speed motor and a high speed motor each of which have been fabricated using samarium cobalt permanent magnet material.

  17. A d.c. magnetic metamaterial.

    PubMed

    Magnus, F; Wood, B; Moore, J; Morrison, K; Perkins, G; Fyson, J; Wiltshire, M C K; Caplin, D; Cohen, L F; Pendry, J B

    2008-04-01

    Electromagnetic metamaterials are a class of materials that have been artificially structured on a subwavelength scale. They are currently the focus of a great deal of interest because they allow access to previously unrealizable properties such as a negative refractive index. Most metamaterial designs have so far been based on resonant elements, such as split rings, and research has concentrated on microwave frequencies and above. Here, we present the first experimental realization of a non-resonant metamaterial designed to operate at zero frequency. Our samples are based on a recently proposed template for an anisotropic magnetic metamaterial consisting of an array of superconducting plates. Magnetometry experiments show a strong, adjustable diamagnetic response when a field is applied perpendicular to the plates. We have calculated the corresponding effective permeability, which agrees well with theoretical predictions. Applications for this metamaterial may include non-intrusive screening of weak d.c. magnetic fields.

  18. AC-DC Power Processor, Type I.

    DTIC Science & Technology

    1979-11-01

    LLI- >- Crto C) UU- LIJj LLJLJ Q 0d CC LJ CC LA exLLIW LL-13- c c. System Waveforms. Figure 6 shows the control system waveforms which includes the...C mJJ9 aJ mi oli o. o o a, aO ~ ~ ’ ’ 0 C. 1.0 r-.J a, 0) a, m- a, 00 00.0 0% (-> ) V - C - q r I 0D 0 0DC < cc 1.0 W 000 a LO~ r- LO Ul) U) Lo UO...o tt ; q ; t .. .. .. I -- ... ...... 0.. .. . . .. . . ~i31b~dI1Ik. ... ... LodA 3dV~~~~.. ....2 ..ZLI ~ ~O 63l t iJ w il. 4 N ... ... . . 4

  19. Dissipative cryogenic filters with zero dc resistance

    NASA Astrophysics Data System (ADS)

    Bluhm, Hendrik; Moler, Kathryn A.

    2008-01-01

    The authors designed, implemented, and tested cryogenic rf filters with zero dc resistance, based on wires with a superconducting core inside a resistive sheath. The superconducting core allows low frequency currents to pass with negligible dissipation. Signals above the cutoff frequency are dissipated in the resistive part due to their small skin depth. The filters consist of twisted wire pairs shielded with copper tape. Above approximately 1GHz, the attenuation is exponential in √ω , as typical for skin depth based rf filters. By using additional capacitors of 10nF per line, an attenuation of at least 45dB above 10MHz can be obtained. Thus, one single filter stage kept at mixing chamber temperature in a dilution refrigerator is sufficient to attenuate room temperature black body radiation to levels corresponding to 10mK above about 10MHz.

  20. Feasibility analysis of the application and positioning of DC HTS FCL in a DC microgrid through modeling and simulation using Simulink and SimPowerSystem

    NASA Astrophysics Data System (ADS)

    Khan, U. A.; Shin, W. J.; Seong, J. K.; Oh, S. H.; Lee, S. H.; Lee, B. W.

    2011-11-01

    DC fault current limitation in DC distribution network is one of the critical issues which need to be taken care of before they can be practically implemented. High temperature superconductors could be efficiently installed to cope with the problem of DC fault currents. In this paper, a generalized DC high temperature superconducting fault current limiter (SFCL) is modeled by integrating Simulink and SimPowerSystem blocks. This model is designed for limiting DC fault currents in low voltage DC distribution networks. A DC microgrid having a low voltage DC distribution network, an integrated photovoltaic plant and domestic customer load is modeled. Transient analysis of the DC microgrid is performed by generating fault and measuring DC fault currents at critical points. The designed DC SFCL is placed at different strategic locations in DC microgrid and fault current limitation performance of DC SFCL in DC microgrid has been analyzed. Moreover, the affects of rapid impedance changing in the distribution network due to the fault followed by DC SFCL activation is investigated. Finally, the best suitable position and affects of DC SFCL in a DC microgrid along with suggestions for implementation have been proposed.

  1. Ion Velocimetry In Magnetized DC Sheaths

    NASA Astrophysics Data System (ADS)

    Young, Christopher; Lucca Fabris, Andrea; Cappelli, Mark

    2013-09-01

    Particle dynamics near the magnetic cusps in cusped field plasma thrusters are still not well understood; characterizing the ion velocity distribution functions in these regions can help thruster designs maximize electron trapping and minimize erosion of the channel wall. To that end, a robust argon ion velocity sensor is developed using a three-level laser-induced fluorescence (LIF) technique. The 3d4F7 / 2 --> 4p4D5/ 2 0 ArII transition at 668.61 nm is pumped with a 25 mW tunable external cavity diode laser, and fluorescence down to the 4s4P3 / 2 state at 442.72 nm is collected with phase-sensitive detection. The Doppler shift in the acquired signal peak, compared to a stationary reference, gives the ion velocity component parallel to the exciting laser. We demonstrate this LIF scheme by obtaining the argon ion velocity profile through a magnetized DC sheath. The LIF measurement is used to validate a new optogalvanic velocimetry technique in which two lasers (chopped at different frequencies) intersect one another at 90° in the measurement volume. Using a lock-in amplifier, changes observed in the DC discharge current at the sum and difference of the two chopping frequencies may be related back to the mean ion velocity at that point. The authors acknowledge support from the Air Force Office of Scientific Research (AFOSR). CY acknowledges support from the DOE NNSA Stewardship Science Graduate Fellowship under contract DE-FC52-08NA28752.

  2. A Compact, Soft-Switching DC-DC Converter for Electric Propulsion

    NASA Technical Reports Server (NTRS)

    Button, Robert; Redilla, Jack; Ayyanar, Raja

    2003-01-01

    A hybrid, soft-switching, DC-DC converter has been developed with superior soft switching characteristics, high efficiency, and low electro-magnetic interference. This hybrid topology is comprised of an uncontrolled bridge operating at full pulse-width, and a controlled section operating as a conventional phase modulated converter. The unique topology is able to maintain zero voltage switching down to no load operating conditions. A breadboard prototype was developed and tested to demonstrate the benefits of the topology. Improvements were then made to reduce the size of passive components and increase efficiency in preparation for packaging. A packaged prototype was then designed and built, and several innovative packaging techniques are presented. Performance test data is presented that reveals deficiencies in the design of the power transformer. A simple redesign of the transformer windings eliminated the deficiency. Future plans to improve the converter and packaging design are presented along with several conclusions.

  3. Low-temperature operation of a Buck DC/DC converter

    NASA Technical Reports Server (NTRS)

    Ray, Biswajit; Gerber, Scott S.; Patterson, Richard L.; Myers, Ira T.

    1995-01-01

    Low-temperature (77 K) operation of a 42/28 V, 175 W, 50 kHz PWM Buck DC/DC converter designed with commercially available components is reported. Overall, the converter losses decreased at 77 K compared to room temperature operation. A full-load efficiency of 97 percent was recorded at liquid-nitrogen temperature, compared to 95.8 percent at room temperature. Power MOSFET operation improved significantly where as the output rectifier operation deteriorated at low-temperature. The performance of the output filter inductor and capacitor did not change significantly at 77 K compared to room temperature performance. It is possible to achieve high-density and high efficiency power conversion at low-temperatures due to improved electronic, electrical and thermal properties of materials.

  4. Table-aided design of the energy-storage reactor in dc-to-dc converters

    NASA Technical Reports Server (NTRS)

    Owen, H. A., Jr.

    1975-01-01

    A new procedure for the selection of magnetic cores for use in energy-storage dc-to-dc power converters which eliminates the need for an automated computer search algorithm and stored data file is presented. The converter configurations included in the procedure are the three commonly encountered single-winding converters for voltage step-up, for current step-up and for voltage step-up/current step-up, and for the two-winding converter for voltage step-up/current step-up. For each converter configuration, three types of controllers are considered - constant-frequency, constant on-time and constant off-time. Using concepts developed from analyses of these converters by considering the transfer of energy by means of an energy-storage inductor or transformer, a special table of parameters calculated from magnetic core data is constructed and leads to a considerably simplified design procedure.

  5. The 25 kW resonant dc/dc power converter

    NASA Technical Reports Server (NTRS)

    Robson, R. R.

    1983-01-01

    The feasibility of processing 25-kW of power with a single, transistorized, series resonant converter stage was demonstrated by the successful design, development, fabrication, and testing of such a device which employs four Westinghouse D7ST transistors in a full-bridge configuration and operates from a 250-to-350 Vdc input bus. The unit has an overall worst-case efficiency of 93.5% at its full rated output of 1000 V and 25 A dc. A solid-state dc input circuit breaker and output-transient-current limiters are included in and integrated into the design. Full circuit details of the converter are presented along with the test data.

  6. High efficiency interleaved bi-directional ZVS DC-DC converter

    NASA Astrophysics Data System (ADS)

    Zafarullah Khan, M.; Mohsin Naveed, M.; Akbar Hussain, D. M.

    2013-06-01

    A high efficiency interleaved bi-directional ZVS DC-DC converter is presented in this paper. This converter can be operated in both buck and boost mode. CoolMOS is used as a power device to achieve low conduction losses and fast turn off. The value of inductance is selected such that the CoolMOS drain-to-source voltage always falls to zero before it turns on and ZVS is achieved. Multiphase interleaved inductors are used to achieve high power and low ripple currents. Converter is operated at 50kHz and MATLAB Simulink simulation is performed. 6kW prototype converter is implemented in buck mode and simulation results are verified.

  7. Practical Design Guidelines of qZSI Based Step-Up DC/DC Converter

    NASA Astrophysics Data System (ADS)

    Zakis, Janis; Vinnikov, Dmitri; Roasto, Indrek; Jalakas, Tanel

    2010-01-01

    This paper presents some design guidelines for a new voltage fed step-up DC/DC isolated converter. The most significant advantage of proposed converter is voltage buck-boost operation on single stage. The most promising application for proposed converter is in the field of distributed power generation e.g. fuel cells or photovoltaic. The most sensitive issues - such as power losses caused by high currents in the input side of converter and high transient overvoltages across the inverter bridge caused by stray inductances were discussed and solved. The proposals and recommendations to overcome these issues are given in the paper. The Selection and design guidelines of converter elements are proposed and explained. The prototype of proposed converter was built and experimentally tested. Some results are presented and evaluated.

  8. A dual VCDL DLL based gate driver for zero-voltage-switching DC-DC converter

    NASA Astrophysics Data System (ADS)

    Xin, Tian; Xiangxin, Liu; Wenhong, Li

    2010-07-01

    This paper presents a dual voltage-controlled-delay-line (VCDL) delay-lock-loop (DLL) based gate driver for a zero-voltage-switching (ZVS) DC-DC converter. Using the delay difference of two VCDLs for the dead time control, the dual VCDL DLL is able to implement ZVS control with high accuracy while keeping good linearity performance of the DLL and low power consumption. The design is implemented in the CSM 2P4M 0.35 μm CMOS process. The measurement results indicate that an efficiency improvement of 2%-4% is achieved over the load current range from 100 to 600 mA at 4 MHz switching frequency with 3.3 V input and 1.3 V output voltage.

  9. DC-DC converters in 0.35μm CMOS technology

    NASA Astrophysics Data System (ADS)

    Michelis, S.; Allongue, B.; Blanchot, G.; Faccio, F.; Fuentes, C.; Orlandi, S.; Saggini, S.; Cengarle, S.; Ongaro, F.

    2012-01-01

    In view of the upgrade of the LHC experiments, we are developing custom DC/DC converters for a more efficient power distribution scheme. A new prototype have been integrated in ASICs in the selected 0.35μm commercial high voltage technology that has been successfully tested for all radiation effects: TID, displacement damage and Single Event Burnout. This converter has been optimized for high efficiency and improved radiation tolerance. Amongst the new features the most relevant are the presence of internal linear regulators, protection circuits with a state-machine and a new pinout for a modified assembly in package in order to reduce conductive losses. This paper illustrates the design of the prototype followed by functional and radiation tests.

  10. The 25 kW resonant dc/dc power converter

    NASA Astrophysics Data System (ADS)

    Robson, R. R.

    1983-09-01

    The feasibility of processing 25-kW of power with a single, transistorized, series resonant converter stage was demonstrated by the successful design, development, fabrication, and testing of such a device which employs four Westinghouse D7ST transistors in a full-bridge configuration and operates from a 250-to-350 Vdc input bus. The unit has an overall worst-case efficiency of 93.5% at its full rated output of 1000 V and 25 A dc. A solid-state dc input circuit breaker and output-transient-current limiters are included in and integrated into the design. Full circuit details of the converter are presented along with the test data.

  11. Interior of elevator house, Block 11, Otis DC exciter (240 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior of elevator house, Block 11, Otis DC exciter (240 volts, 1200 rpm), Otis DC Generator (280 volts, 1200 rpm), and control panel, view looking west. - Columbia Basin Project, Grand Coulee Dam & Franklin D. Roosevelt Lake, Across Columbia River, Southeast of Town of Grand Coulee, Grand Coulee, Grant County, WA

  12. Integrated-Circuit Controller For Brushless dc Motor

    NASA Technical Reports Server (NTRS)

    Le, Dong Tuan

    1994-01-01

    Generic circuit performs commutation-logic and power-switching functions for control of brushless dc motor. Controller includes commutation-logic and associated control circuitry, power supply, and inverters containing power transistors. Major advantages of controller are size, weight, and power consumption can be made less than other brushless-dc-motor controllers.

  13. The Proving Grounds: School "Rheeform" in Washington, D.C.

    ERIC Educational Resources Information Center

    Dingerson, Leigh

    2010-01-01

    Washington, D.C., is leading the transformation of urban public education across the country--at least according to "Time" magazine, which featured D.C. Schools Chancellor Michelle Rhee on its cover, wearing black and holding a broom. But there is nothing remarkably visionary going on in Washington. The model of school reform that is…

  14. Read-out electronics for DC squid magnetic measurements

    DOEpatents

    Ganther, Jr., Kenneth R.; Snapp, Lowell D.

    2002-01-01

    Read-out electronics for DC SQUID sensor systems, the read-out electronics incorporating low Johnson noise radio-frequency flux-locked loop circuitry and digital signal processing algorithms in order to improve upon the prior art by a factor of at least ten, thereby alleviating problems caused by magnetic interference when operating DC SQUID sensor systems in magnetically unshielded environments.

  15. Solid-state ac-to-dc converter

    NASA Technical Reports Server (NTRS)

    Monroe, C. M.

    1970-01-01

    Converter uses solid-state ac-to-dc rectification circuitry, filter circuitry, a tuned transformer, ac chopper circuitry, and an automatic current-control network. It has a dc power source which operates from 5 to 100 percent load at a 72 to 94 input to output efficiency.

  16. 38 CFR 3.851 - St. Elizabeths Hospital, Washington, DC.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2013-07-01 2013-07-01 false St. Elizabeths Hospital, Washington, DC. 3.851 Section 3.851 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS... Institutional Awards § 3.851 St. Elizabeths Hospital, Washington, DC. Benefits due or becoming due any...

  17. 38 CFR 3.851 - St. Elizabeths Hospital, Washington, DC.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2011-07-01 2011-07-01 false St. Elizabeths Hospital, Washington, DC. 3.851 Section 3.851 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS... Institutional Awards § 3.851 St. Elizabeths Hospital, Washington, DC. Benefits due or becoming due any...

  18. 75 FR 11583 - District of Columbia Disaster #DC-00001

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-11

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION District of Columbia Disaster DC-00001 AGENCY: U.S. Small Business Administration. ACTION: Notice..., Washington, DC 20416. SUPPLEMENTARY INFORMATION: Notice is hereby given that as a result of the...

  19. 75 FR 17791 - District of Columbia Disaster # DC-00002

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-07

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION District of Columbia Disaster DC-00002 AGENCY: U.S. Small Business Administration. ACTION: Notice...., Suite 6050, Washington, DC 20416. SUPPLEMENTARY INFORMATION: Notice is hereby given that as a result...

  20. 38 CFR 3.851 - St. Elizabeths Hospital, Washington, DC.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2014-07-01 2014-07-01 false St. Elizabeths Hospital, Washington, DC. 3.851 Section 3.851 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS... Institutional Awards § 3.851 St. Elizabeths Hospital, Washington, DC. Benefits due or becoming due any...

  1. 38 CFR 3.851 - St. Elizabeths Hospital, Washington, DC.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false St. Elizabeths Hospital, Washington, DC. 3.851 Section 3.851 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS... Institutional Awards § 3.851 St. Elizabeths Hospital, Washington, DC. Benefits due or becoming due any...

  2. 38 CFR 3.851 - St. Elizabeths Hospital, Washington, DC.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2012-07-01 2012-07-01 false St. Elizabeths Hospital, Washington, DC. 3.851 Section 3.851 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS... Institutional Awards § 3.851 St. Elizabeths Hospital, Washington, DC. Benefits due or becoming due any...

  3. A Design Methodology for Switched-Capacitor DC-DC Converters

    DTIC Science & Technology

    2009-05-21

    was simulated in a 65 nm process. One curve shows the bottom-plate parasitic if the well is tied to a DC potential above the substrate, such that the...182 A.4.3 Discrete-Time Model . . . . . . . . . . . . . . . . . . . . . . . . . . . 186 A.4.4 Dynamics Simulation ...5.4 Double-bound hysteresis feedback for the PicoCube application . . . . . . . 89 5.5 Lower-bound hysteretic feedback controller

  4. Load adaptive start-up scheme for synchronous boost DC-DC converter

    NASA Astrophysics Data System (ADS)

    Guoding, Dai; Wenliang, Xiu; Yuezhi, Liu; Yawei, Qi; Zuqi, Dong

    2016-10-01

    This paper presents a load adaptive soft-start scheme through which the inductor current of the synchronous boost DC-DC converter can trace the load current at the start-up stage. This scheme effectively eliminates the inrush-current and over-shoot voltage and improves the load capability of the converter. According to the output voltage, the start-up process is divided into three phases and at each phase the inductor current is limited to match the load. In the pre-charge phase, a step-increasing constant current gives a smooth rise of the output voltage which avoids inrush current and ensures the converter successfully starts up at different load situations. An additional ring oscillator operation phase enables the converter to start up as low as 1.4 V. When the converter enters into the system loop soft-start phase, an output voltage and inductor current detection methods make the transition of the phases smooth and the inductor current and output voltage rise steadily. Effective protection circuits such as short-circuit protection, current limit circuit and over-temperature protection circuit are designed to guarantee the safety and reliability of the chip during the start-up process. The proposed start-up circuit is implemented in a synchronous boost DC-DC converter based on TSMC 0.35 μm CMOS process with an input voltage range 1.4-4.2 V, and a steady output voltage 5 V, and the switching frequency is 1 MHz. Simulation results show that inrush current and overshoot voltage are suppressed with a load range from 0-2.1 A, and inductor current is as low as 259 mA when the output shorts to the ground.

  5. Simulating and Testing a DC-DC Half-Bridge SLR Converter

    DTIC Science & Technology

    2013-06-01

    Continuous Conduction Mode DC Direct Current DCM Discontinuous Conduction Mode FPGA Field-programmable Gate Array MOSFET Metal-Oxide Semiconductor...angular frequency oω is used to determine how to gate the MOSFET switches, achieving zero current switching. At switching frequencies sω , where 0...must occur during DCM operations). MOSFET T − is then gated on for the fourth interval, li starts negative, and when the current reaches a

  6. Historical Material Analysis of DC745U Pressure Pads

    SciTech Connect

    Ortiz-Acosta, Denisse

    2012-07-30

    As part of the Enhance Surveillance mission, it is the goal to provide suitable lifetime assessment of stockpile materials. This report is an accumulation of historical publication on the DC745U material and their findings. It is the intention that the B61 LEP program uses this collection of data to further develop their understanding and potential areas of study. DC745U is a commercially available silicone elastomer consisting of dimethyl, methyl-phenyl, and methyl-vinyl siloxane repeat units. Originally, this material was manufactured by Dow Corning as Silastic{reg_sign} DC745U at their manufacturing facility in Kendallville, IN. Recently, Dow Corning shifted this material to the Xiameter{reg_sign} brand product line. Currently, DC745U is available through Xiameter{reg_sign} or Dow Corning's distributor R. D. Abbott Company. DC745U is cured using 0.5 wt% vinyl-specific peroxide curing agent known as Luperox 101 or Varox DBPH-50. This silicone elastomer is used in numerous parts, including two major components (outer pressure pads and aft cap support) in the W80 and as pressure pads on the B61. DC745U is a proprietary formulation, thus Dow Corning provides limited information on its composition and properties. Based on past experience with Dow Corning, DC745U is at risk of formulation changes without notification to the costumer. A formulation change for DC745U may have a significant impact because the network structure is a key variable in determining material properties. The purpose of this report is to provide an overview of historical DC745U studies and identify gaps that need to be addressed in future work. Some of the previous studies include the following: 1. Spectroscopic characterization of raw gum stock. 2. Spectroscopic, thermal, and mechanical studies on cured DC745U. 3. Nuclear Magnetic Resonance (NMR) and solvent swelling studies on DC745U with different crosslink densities. 4. NMR, solvent swelling, thermal, and mechanical studies on thermally aged

  7. Design of piezoelectric transformer for DC/DC converter with stochastic optimization method

    NASA Astrophysics Data System (ADS)

    Vasic, Dejan; Vido, Lionel

    2016-04-01

    Piezoelectric transformers were adopted in recent year due to their many inherent advantages such as safety, no EMI problem, low housing profile, and high power density, etc. The characteristics of the piezoelectric transformers are well known when the load impedance is a pure resistor. However, when piezoelectric transformers are used in AC/DC or DC/DC converters, there are non-linear electronic circuits connected before and after the transformer. Consequently, the output load is variable and due to the output capacitance of the transformer the optimal working point change. This paper starts from modeling a piezoelectric transformer connected to a full wave rectifier in order to discuss the design constraints and configuration of the transformer. The optimization method adopted here use the MOPSO algorithm (Multiple Objective Particle Swarm Optimization). We start with the formulation of the objective function and constraints; then the results give different sizes of the transformer and the characteristics. In other word, this method is looking for a best size of the transformer for optimal efficiency condition that is suitable for variable load. Furthermore, the size and the efficiency are found to be a trade-off. This paper proposes the completed design procedure to find the minimum size of PT in need. The completed design procedure is discussed by a given specification. The PT derived from the proposed design procedure can guarantee both good efficiency and enough range for load variation.

  8. Development of a Novel Bi-Directional Isolated Multiple-Input DC-DC Converter

    SciTech Connect

    Li, H.

    2005-10-24

    There is vital need for a compact, lightweight, and efficient energy-storage system that is both affordable and has an acceptable cycle life for the large-scale production of electric vehicles (EVs) and hybrid electric vehicles (HEVs). Most of the current research employs a battery-storage unit (BU) combined with a fuel cell (FC) stack in order to achieve the operating voltage-current point of maximum efficiency for the FC system. A system block diagram is shown in Fig.1.1. In such a conventional arrangement, the battery is sized to deliver the difference between the energy required by the traction drive and the energy supplied by the FC system. Energy requirements can increase depending on the drive cycle over which the vehicle is expected to operate. Peak-power transients result in an increase of losses and elevated temperatures which result in a decrease in the lifetime of the battery. This research will propose a novel two-input direct current (dc) dc to dc converter to interface an additional energy-storage element, an ultracapacitor (UC), which is shown in Fig.1.2. It will assist the battery during transients to reduce the peak-power requirements of the battery.

  9. Multiphase High-Frequency Isolated DC-DC Converter for Industrial Applications

    NASA Astrophysics Data System (ADS)

    Maurya, Rakesh; Srivastava, S. P.; Agarwal, Pramod

    2014-01-01

    Industrial applications such as welding, plasma cutting, and surface hardening require a large DC current at low voltage. In such applications, the rating of power supply varies from few kilowatts to hundreds of kilowatts. The power supply employs in such applications particularly in arc welding process is expected to operate from open-circuit (no-load) to short-circuit (when the electrode sticks to the workpiece for a short span of time) quickly. In this paper, high-frequency isolated multiphase DC-DC converter is proposed which is well suited for aforementioned applications. Based on mathematical analysis, a simulation study with 5 kW, 5 V/1,000 A proposed model is carried out using Simulink block set and Sim Power System tool box and its performances are evaluated under symmetrical control methods. To verify the simulation results, scaled prototype model of rating 1.5 V/100 A is developed and tested with aforementioned control method under different operating conditions. In comparison with conventional welding power supply employed in many industries, the performance of proposed converter is improved significantly in terms of size and weight, efficiency and dynamic response.

  10. Performance of a Voltage Step-Up/Step-Down Transformerless DC/DC Converter: Analytical Model

    NASA Astrophysics Data System (ADS)

    Suskis, P.; Rankis, I.

    2012-01-01

    The authors present an analytical model for a voltage step-up/step-down DC/DC converter without transformers. The proposed topology is a combination of classic buck and boost converters in one single circuit but with differing operational principles. The converter is developed for a wind power autonomous supply system equipped with a hydrogen electrolytic tank and a fuel cell for energy stabilization. The main power source of the hydrogen-based autonomous supply system is energized by a synchronous generator operating on permanent magnets and equipped with a diode bridge. The input voltage of the converter in this case varies in the range 0-700 V, while its output DC voltage must be 540 V according to the demand of other parts of the system. To maintain the rated voltage, a special electrical load regulation is introduced. The calculations of the converter, the generator (equipped with a diode bridge) as element of the power system supply joint, and the load replaced by resistance are verified with PSIM software.

  11. DC-SIGN(+) Macrophages Control the Induction of Transplantation Tolerance.

    PubMed

    Conde, Patricia; Rodriguez, Mercedes; van der Touw, William; Jimenez, Ana; Burns, Matthew; Miller, Jennifer; Brahmachary, Manisha; Chen, Hui-ming; Boros, Peter; Rausell-Palamos, Francisco; Yun, Tae Jin; Riquelme, Paloma; Rastrojo, Alberto; Aguado, Begoña; Stein-Streilein, Joan; Tanaka, Masato; Zhou, Lan; Zhang, Junfeng; Lowary, Todd L; Ginhoux, Florent; Park, Chae Gyu; Cheong, Cheolho; Brody, Joshua; Turley, Shannon J; Lira, Sergio A; Bronte, Vincenzo; Gordon, Siamon; Heeger, Peter S; Merad, Miriam; Hutchinson, James; Chen, Shu-Hsia; Ochando, Jordi

    2015-06-16

    Tissue effector cells of the monocyte lineage can differentiate into different cell types with specific cell function depending on their environment. The phenotype, developmental requirements, and functional mechanisms of immune protective macrophages that mediate the induction of transplantation tolerance remain elusive. Here, we demonstrate that costimulatory blockade favored accumulation of DC-SIGN-expressing macrophages that inhibited CD8(+) T cell immunity and promoted CD4(+)Foxp3(+) Treg cell expansion in numbers. Mechanistically, that simultaneous DC-SIGN engagement by fucosylated ligands and TLR4 signaling was required for production of immunoregulatory IL-10 associated with prolonged allograft survival. Deletion of DC-SIGN-expressing macrophages in vivo, interfering with their CSF1-dependent development, or preventing the DC-SIGN signaling pathway abrogated tolerance. Together, the results provide new insights into the tolerogenic effects of costimulatory blockade and identify DC-SIGN(+) suppressive macrophages as crucial mediators of immunological tolerance with the concomitant therapeutic implications in the clinic.

  12. NK-DC Crosstalk in Immunity to Microbial Infection

    PubMed Central

    Thomas, Rony

    2016-01-01

    The interaction between natural killer (NK) cell and dendritic cell (DC), two important cellular components of innate immunity, started to be elucidated in the last years. The crosstalk between NK cells and DC, which leads to NK cell activation, DC maturation, or apoptosis, involves cell-cell contacts and soluble factors. This interaction either in the periphery or in the secondary lymphoid organs acts as a key player linking innate and adaptive immune responses to microbial stimuli. This review focuses on the mechanisms of NK-DC interaction and their relevance in antimicrobial responses. We specifically aim to emphasize the ability of various microbial infections to differently influence NK-DC crosstalk thereby contributing to distinct adaptive immune response. PMID:28097157

  13. Trends of DC Power Technologies and their Applications

    NASA Astrophysics Data System (ADS)

    Hirose, Keiichi

    Renewable energy resources such as photovoltaic panels and wind turbines have been increasing rapidly to prevent global warming. The number of energy storage systems and many types of batteries is also growing to keep supply and demand balance in local areas. Interfaces of these facilities are direct current (DC). Most of modern electrical appliances also use DC power inside them. Therefore, DC power technologies with some features are expected to meet requirements for new electrical power systems, for example smartgrids, microgrids, and other electrical applications. In recent years, DC power applications in data centers, commercial buildings, and dwellings have been developed in Japan, the U.S. European countries, and so on. At the same time, international standardization activities had started. This paper describes trends of DC power technologies and their applications.

  14. Step-by-Step Design of an FPGA-Based Digital Compensator for DC/DC Converters Oriented to an Introductory Course

    ERIC Educational Resources Information Center

    Zumel, P.; Fernandez, C.; Sanz, M.; Lazaro, A.; Barrado, A.

    2011-01-01

    In this paper, a short introductory course to introduce field-programmable gate array (FPGA)-based digital control of dc/dc switching power converters is presented. Digital control based on specific hardware has been at the leading edge of low-medium power dc/dc switching converters in recent years. Besides industry's interest in this topic, from…

  15. User's manual: Computer-aided design programs for inductor-energy-storage dc-to-dc electronic power converters

    NASA Technical Reports Server (NTRS)

    Huffman, S.

    1977-01-01

    Detailed instructions on the use of two computer-aided-design programs for designing the energy storage inductor for single winding and two winding dc to dc converters are provided. Step by step procedures are given to illustrate the formatting of user input data. The procedures are illustrated by eight sample design problems which include the user input and the computer program output.

  16. A 10 kW dc-dc converter using IGBTs with active snubbers. [Insulated Gate Bipolar Transistor

    NASA Technical Reports Server (NTRS)

    Masserant, Brian J.; Shriver, Jeffrey L.; Stuart, Thomas A.

    1993-01-01

    This full bridge dc-dc converter employs zero voltage switching (ZVS) on one leg and zero current switching (ZCS) on the other. This technique produces exceptionally low IGBT switching losses through the use of an active snubber that recycles energy back to the source. Experimental results are presented for a 10 kW, 20 kHz converter.

  17. Nearly Unity Power-Factor of the Modular Three-Phase AC to DC Converter with Minimized DC Bus Capacitor

    NASA Astrophysics Data System (ADS)

    Chunkag, Viboon; Kamnarn, Uthen

    The analysis and design of nearly unity power-factor and fast dynamic response of the modular three-phase ac to dc converter using three single-phase isolated SEPIC rectifier modules with minimized dc bus capacitor is discussed, based on power balance control technique. The averaged small-signal technique is used to obtain the inductor current compensator, thus resulting in the output impedance and audio susceptibility become zero, that is, the output voltage of the converter presented in this paper is independent of the variations of the dc load current and the utility voltage. The proposed system significantly improves the dynamic response of the converter to load steps with minimized dc bus capacitor for Distributed Power System (DPS). A 600W prototype modular three-phase ac to dc converter comprising three 200W single-phase SEPIC rectifier modules with the proposed control scheme has been designed and implemented. The proposed system is confirmed by experimental implementation.

  18. DC66842 VIEW WEST FROM BANNEKER CIRCLE (RESERVATION NO. 719) TO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DC-668-42 VIEW WEST FROM BANNEKER CIRCLE (RESERVATION NO. 719) TO THE DOME OF THE JEFFERSON MEMORIAL IN WEST POTOMAC PARK - L'Enfant-McMillan Plan of Washington, DC, Washington, District of Columbia, DC

  19. DC6684 AERIAL VIEW LOOKING SLIGHTLY SOUTHEAST DOWN THE NORTH CAPITOL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DC-668-4 AERIAL VIEW LOOKING SLIGHTLY SOUTHEAST DOWN THE NORTH CAPITOL STREET CORRIDOR FROM ABOVE THE RHODE ISLAND AVENUE VICINITY - L'Enfant-McMillan Plan of Washington, DC, Washington, District of Columbia, DC

  20. DC66813 AERIAL VIEW OF THE NORTHWEST QUADRANT, LOOKING NORTH UP ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DC-668-13 AERIAL VIEW OF THE NORTHWEST QUADRANT, LOOKING NORTH UP THE 2 3RD STREET CORRIDOR FROM ABOVE WEST POTOMAC PARK - L'Enfant-McMillan Plan of Washington, DC, Washington, District of Columbia, DC

  1. DC66843 VIEW OF THE INDEPENDENCE AVENUE CORRIDOR SPANNED BY THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DC-668-43 VIEW OF THE INDEPENDENCE AVENUE CORRIDOR SPANNED BY THE •DEPARTMENT OF AGRICULTURE BRIDGES, LOOKING WEST FROM TWELFTH STREET, SW - L'Enfant-McMillan Plan of Washington, DC, Washington, District of Columbia, DC

  2. DC66814 AERIAL VIEW OF THE CAPITOL REFLECTING POOL, LOOKING NORTHEAST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DC-668-14 AERIAL VIEW OF THE CAPITOL REFLECTING POOL, LOOKING NORTHEAST UP LOUISIANA AVENUE TOWARD UNION STATION FROM ABOVE THE MALL - L'Enfant-McMillan Plan of Washington, DC, Washington, District of Columbia, DC

  3. 78 FR 37104 - Establishment of Area Navigation (RNAV) Routes; Washington, DC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-20

    ...) Routes; Washington, DC AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule; correction..., that establishes five RNAV routes in support of the Washington, DC, Optimization of Airspace and..., Federal Aviation Administration, 800 Independence Avenue SW., Washington, DC 20591; telephone: (202)...

  4. DC66820 VISTA EAST ALONG M STREET TO THOMAS CIRCLE FROM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DC-668-20 VISTA EAST ALONG M STREET TO THOMAS CIRCLE FROM RESERVATION NO. 14 0 AT NEW HAMPSHIRE AVENUE AND 21ST STREET, NW - L'Enfant-McMillan Plan of Washington, DC, Washington, District of Columbia, DC

  5. DC66840 VIEW EAST ON THE SOUTHEAST/SOUTHWEST FREEWAY (IN THE HISTORIC ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DC-668-40 VIEW EAST ON THE SOUTHEAST/SOUTHWEST FREEWAY (IN THE HISTORIC F STREET CORRIDOR) FROM THE TENTH STREET PROMENADE, SW - L'Enfant-McMillan Plan of Washington, DC, Washington, District of Columbia, DC

  6. DC65819 VIEW NORTHWEST ALONG THE POTOMAC RIVERFRONT AND INTO GEORGETOWN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DC-658-19 VIEW NORTHWEST ALONG THE POTOMAC RIVERFRONT AND INTO GEORGETOWN FROM THE ROOF OF THE JOHN F. KENNEDY CENTER FOR THE PERFORMING ARTS - L'Enfant-McMillan Plan of Washington, DC, Washington, District of Columbia, DC

  7. Association of DC-SIGNR Expression in Peripheral Blood Mononuclear Cells with DC-SIGNR Genotypes in HIV-1 Infection.

    PubMed

    Chaudhary, Omkar; Kumar, Sanjeev; Bala, Manju; Singh, Jasbir; Hazarika, Anjali; Luthra, Kalpana

    2015-10-01

    Dendritic cell-specific intracellular adhesion molecule 3 grabbing nonintegrin related molecule (DC-SIGNR) is a C-type lectin, calcium-dependent carbohydrate-binding protein, which can act as a cell-adhesion and pathogen recognition receptor. DC-SIGNR is known to be highly expressed on liver sinusoidal cells and in the lymph nodes. However, its expression in peripheral blood mononuclear cells (PBMCs) in HIV-1 infection has not been addressed. Therefore, this study determined the expression of DC-SIGNR in PBMCs of HIV-1-infected patients and healthy seronegative individuals by real-time polymerase chain reaction and assessed its correlation with CD4+ T cell counts and DC-SIGNR genotypes. A significantly higher expression of DC-SIGNR was observed in the PBMCs of HIV-1-infected patients compared with healthy seronegative individuals. Further, there was a negative correlation between DC-SIGNR expression and CD4+ T cell counts and positive with viral load, with higher DC-SIGNR expression in the PBMCs of HIV-1-infected patients with a CD4+ T cell count <200 cells/μL than those with >200 cells/μL. This is the first study to report the expression of DC-SIGNR in PBMCs of HIV-1-infected patients. A salient finding of this study is that the DC-SIGNR expression was higher in HIV-1-infected patients, and its positive correlation with viral load and negative with CD4+ T cells counts suggesting a potential role of DC-SIGNR in HIV-1 infection.

  8. 75 FR 35611 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, and MD-10-10F...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-23

    ... Corporation Model DC- 10-10, DC-10-10F, and MD-10-10F Airplanes AGENCY: Federal Aviation Administration (FAA... DC-10-10, DC-10-10F, and MD-10-10F airplanes. This AD requires a one-time high frequency eddy current... instances of Model DC-10-10F airplanes having fuel leaks in the wing rear spar lower cap at station...

  9. Blind signal processing algorithms under DC biased Gaussian noise

    NASA Astrophysics Data System (ADS)

    Kim, Namyong; Byun, Hyung-Gi; Lim, Jeong-Ok

    2013-05-01

    Distortions caused by the DC-biased laser input can be modeled as DC biased Gaussian noise and removing DC bias is important in the demodulation process of the electrical signal in most optical communications. In this paper, a new performance criterion and a related algorithm for unsupervised equalization are proposed for communication systems in the environment of channel distortions and DC biased Gaussian noise. The proposed criterion utilizes the Euclidean distance between the Dirac-delta function located at zero on the error axis and a probability density function of biased constant modulus errors, where constant modulus error is defined by the difference between the system out and a constant modulus calculated from the transmitted symbol points. From the results obtained from the simulation under channel models with fading and DC bias noise abruptly added to background Gaussian noise, the proposed algorithm converges rapidly even after the interruption of DC bias proving that the proposed criterion can be effectively applied to optical communication systems corrupted by channel distortions and DC bias noise.

  10. Pedestrian crashes in Washington, DC and Baltimore.

    PubMed

    Preusser, David F; Wells, JoAnn K; Williams, Allan F; Weinstein, Helen B

    2002-09-01

    Police crash reports were obtained for pedestrian-motor vehicle crashes in Washington, DC (N = 852) and Baltimore (N = 1234) for the year 1998. Reports were coded using procedures developed and applied in these two cities during the 1970s, including the determination of pedestrian crash type, primary precipitating factor, and culpability. Results indicated substantial differences between crash patterns observed during the 1970s and those observed during 1998. Midblock dart-dash crashes, which typically involve a precipitating factor or critical error by a child pedestrian, decreased (from 37% to 15% in Washington). Across all crashes in both cities, the number of drivers who made a critical error leading to the crash was nearly equivalent to the number of pedestrians who made a critical error. Overall, pedestrians were slightly more likely to be judged culpable (50% vs. 39%). Turning vehicle crashes, which typically involve a driver's failure to grant a pedestrian the right of way at a signalized intersection, increased (from 9% to 25% in Washington). Countermeasures to reduce the number of pedestrians hit by turning vehicles are discussed.

  11. Antarctic Treaty Summit: Washington, DC (2009)

    NASA Astrophysics Data System (ADS)

    Berkman, P. A.; Young, O. R.

    2005-12-01

    Advancement in Earth system science and international cooperation have been intertwined with the International Polar Years since 1882. In particular, the 3rd International Polar Year (which was convened as the International Geophysical Year from 1 July 1957 through 31 December 1958) specifically demonstrates the role of science in international policy: Acknowledging the substantial contributions to scientific knowledge resulting from international cooperation in scientific investigation in Antarctica; Convinced that the establishment of a firm foundation for the continuation and development of such cooperation on the basis of freedom of scientific investigation in Antarctica as applied during the International Geophysical Year accords with the interests of science and the progress of all mankind; Preamble, 1959 Antarctic Treaty To commemorate the 50th anniversary of the 1959 Antarctic Treaty and to explore the complexities of the science-policy relationship through the lens of a well-constrained case study, an international and interdisciplinary Antarctic Treaty Summit is being planned for 2009 in Washington, DC in conjunction with the International Polar Year 2007-08 (http://www.ipy.org).

  12. Biological effects of high DC magnetic fields

    SciTech Connect

    Tenforde, T.S.

    1981-06-01

    The principal focus of the program is the analysis of magnetic field effects on physiological functions in experimental animals and selected organ and tissue systems. A major research effort has involved the use of electrical recording techniques to detect functional alterations in the cardiovascular, neural, and visual systems during the application of DC magnetic fields. These systems involve ionic conduction processes, and are therefore potentially sensitive to electrodynamic interactions with an applied magnetic field. In the specific case of the visual system, magnetic interactions could also arise through orientational effects on the magnetically anisotropic photopigment molecules within retinal photoreceptor cells. In addition to studies with potentially sensitive target tissues, an evaluation is being made of magnetic field effects on a broad range of other physiological functions in laboratory mammals, including the measurement of circadian rhythms using noninvasive recording techniques. Results of investigations of magnetic field effects on the conformation of DNA, and on the growth and development of plants and insects are also reported. Figures and tables provide a brief summary of some representative observations in each of the research areas described. No significant alterations were observed in any of the physiological parameters examined to date, with the exception of major changes that occur in the electrocardiogram during magnetic field exposure. Studies with several species of animals have provided evidence that this phenomenon is attributable to electrical potentials that are induced during pulsatile blood flow in the aorta and in other major vessels of the circulatory system.

  13. Motor control for a brushless DC motor

    NASA Technical Reports Server (NTRS)

    Peterson, William J. (Inventor); Faulkner, Dennis T. (Inventor)

    1985-01-01

    This invention relates to a motor control system for a brushless DC motor having an inverter responsively coupled to the motor control system and in power transmitting relationship to the motor. The motor control system includes a motor rotor speed detecting unit that provides a pulsed waveform signal proportional to rotor speed. This pulsed waveform signal is delivered to the inverter to thereby cause an inverter fundamental current waveform output to the motor to be switched at a rate proportional to said rotor speed. In addition, the fundamental current waveform is also pulse width modulated at a rate proportional to the rotor speed. A fundamental current waveform phase advance circuit is controllingly coupled to the inverter. The phase advance circuit is coupled to receive the pulsed waveform signal from the motor rotor speed detecting unit and phase advance the pulsed waveform signal as a predetermined function of motor speed to thereby cause the fundamental current waveform to be advanced and thereby compensate for fundamental current waveform lag due to motor winding reactance which allows the motor to operate at higher speeds than the motor is rated while providing optimal torque and therefore increased efficiency.

  14. Spacelab ready for transport to Washington, DC

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Spacelab is wrapped and ready for transport to the National Air and Space Museum in Washington, DC. Spacelab was designed by the European Space Agency (ESA) for the Space Shuttle program and first flew on STS-9 in November 1983. Its final flight was the STS-90 Neurolab mission in April 1998. A sister module will travel home and be placed on display in Europe. The Spacelab concept of modular experiment racks in a pressurized shirt-sleeve environment made it highly user-friendly and accessible. Numerous experiments conceived by hundreds of scientists on the ground were conducted by flight crews in orbit. Spacelab modules served as on-orbit homes for everything from squirrel monkeys to plant seeds. They supported astronomical as well as Earth observations, for servicing the Hubble Space Telescope and for research preparatory to the International Space Station. One of the greatest benefits afforded by the Spacelab missions was the opportunity to fly a mission more than once, with the second or third flight building on the experiences and data gathered from its predecessors.

  15. Analytical derivation of DC SQUID response

    NASA Astrophysics Data System (ADS)

    Soloviev, I. I.; Klenov, N. V.; Schegolev, A. E.; Bakurskiy, S. V.; Kupriyanov, M. Yu

    2016-09-01

    We consider voltage and current response formation in DC superconducting quantum interference device (SQUID) with overdamped Josephson junctions in resistive and superconducting state in the context of a resistively shunted junction (RSJ) model. For simplicity we neglect the junction capacitance and the noise effect. Explicit expressions for the responses in resistive state were obtained for a SQUID which is symmetrical with respect to bias current injection point. Normalized SQUID inductance l=2{{eI}}{{c}}L/{\\hslash } (where I c is the critical current of Josephson junction, L is the SQUID inductance, e is the electron charge and ℏ is the Planck constant) was assumed to be within the range l ≤ 1, subsequently expanded up to l≈ 7 using two fitting parameters. SQUID current response in the superconducting state was considered for arbitrary value of the inductance. The impact of small technological spread of parameters relevant to low-temperature superconductor (LTS) technology was studied, using a generalization of the developed analytical approach, for the case of a small difference of critical currents and shunt resistances of the Josephson junctions, and inequality of SQUID inductive shoulders for both resistive and superconducting states. Comparison with numerical calculation results shows that developed analytical expressions can be used in practical LTS SQUIDs and SQUID-based circuits design, e.g. large serial SQIF, drastically decreasing the time of simulation.

  16. Implementing the DC Mode in Cosmological Simulations with Supercomoving Variables

    SciTech Connect

    Gnedin, Nickolay Y; Kravtsov, Andrey V; Rudd, Douglas H

    2011-06-02

    As emphasized by previous studies, proper treatment of the density fluctuation on the fundamental scale of a cosmological simulation volume - the 'DC mode' - is critical for accurate modeling of spatial correlations on scales ~> 10% of simulation box size. We provide further illustration of the effects of the DC mode on the abundance of halos in small boxes and show that it is straightforward to incorporate this mode in cosmological codes that use the 'supercomoving' variables. The equations governing evolution of dark matter and baryons recast with these variables are particularly simple and include the expansion factor, and hence the effect of the DC mode, explicitly only in the Poisson equation.

  17. DC information preservation for cardiopulmonary monitor utilizing CW Doppler radar.

    PubMed

    Vergara, Alexander M; Boric-Lubecke, Olga; Lubecke, Victor M

    2008-01-01

    Direct conversion RF receivers introduce large DC offsets, reducing the dynamic range of the baseband signal. Coupled with the relatively small time varying signals in human vital sign monitoring using CW Doppler radar, extraction of cardio-pulmonary information becomes difficult. Previous DC offset compensation techniques utilizing AC coupling have proven detrimental to the performance of the system and the integrity of the low-frequency cardiopulmonary signals. A proposed system utilizing digitally controlled voltage feedback and center finding preserves the important DC information for optimal extraction of phase information in the quadrature system.

  18. A general unified approach to modelling switching dc-to-dc converters in discontinuous conduction mode

    NASA Technical Reports Server (NTRS)

    Cuk, S.; Middlebrook, R. D.

    1977-01-01

    A method for modelling switching converters in the discontinuous conduction mode is developed, whose starting point is the unified state-space representation, and whose end result is a complete linear circuit model which correctly represents all essential features, namely, the input, output, and transfer properties (static dc as well as dynamic ac small signal). While the method is generally applicable to any switching converter operating in the discontinuous conduction mode, it is extensively illustrated for the three common power stages (buck, boost, and buck-boost). The results for these converters are then easily tabulated owing to the fixed equivalent circuit topology of their canonical circuit model.

  19. High reliability DC/DC converter module for electronic boards equipped with FPGAs

    NASA Astrophysics Data System (ADS)

    Viganò, W.; Boccardi, A.; Zamantzas, C.

    2015-01-01

    The Beam Instrumentation Group at CERN is designing a new general-purpose VME carrier module utilising several PTH04T230W DC/DC converters. These off-the-shelf converters are built with unshielded inductors and need to be mounted on the printed circuit board as stand-alone components. Thus, reducing the global manageability and increasing the total cost of the carrier module. The new design aims to develop a module with better power dissipation, efficiency and reliability. In the future, it should be also possible to be directly integrated on the mainboard. For this reason, a Buck DC/DC converter has been implemented with the following main characteristics: input range from 3.0 V to 5.5 V; output range from 0.6 V to 3.3 V, settable by means of an external resistor; output current protection at 6 A; maximum output ripple ± 50 mVpp; switching frequency of 300KHz; short circuit protection; On/Off function; EMI reduction with frequency spread spectrum; soft-start function and thermal shutdown, in a 16 × 19 mm compact size. The selected buck controller is the TPS40303 integrated circuit and drives the CSD16321 power MOSFET, both from Texas Instruments. All selected components have been used at a minimum derating of 50% to reduce component stress and increase the reliability of this module. The selected inductors, i.e. Bourns SRP1055, are the main contributor for the high efficiency (95%), due to their very low equivalent series resistance. On the 4-layer PCB comprising all the components of this module, a snubber circuit, for further reduction of the output ripple due to the MOSFET ringing, can be mounted optionally. It is left as an option due to its effect on the total efficiency. The board layout has been optimized for maximum heat transfer and it can be used without active cooling. The board can maintain the maximum temperature on its surface, while at maximum current output, below 55°C at 25°C ambient temperature. An example of the electrical performance

  20. Oligomerization domains in the glycan-binding receptors DC-SIGN and DC-SIGNR: Sequence variation and stability differences.

    PubMed

    Dos Santos, Ália; Hadjivasiliou, Andreas; Ossa, Felipe; Lim, Novandy K; Turgut, Aylin; Taylor, Maureen E; Drickamer, Kurt

    2017-02-01

    Human dendritic cell-specific intercellular adhesion molecule-1 grabbing nonintegrin, DC-SIGN, and the sinusoidal endothelial cell receptor DC-SIGNR or L-SIGN, are closely related sugar-binding receptors. DC-SIGN acts both as a pathogen-binding endocytic receptor and as a cell adhesion molecule, while DC-SIGNR has only the pathogen-binding function. In addition to differences in the sugar-binding properties of the carbohydrate-recognition domains in the two receptors, there are sequence differences in the adjacent neck domains, which are coiled-coil tetramerization domains comprised largely of 23-amino acid repeat units. A series of model polypeptides consisting of uniform repeat units have been characterized by gel filtration, differential scanning calorimetry and circular dichroism. The results demonstrate that two features characterize repeat units which form more stable tetramers: a leucine reside in the first position of the heptad pattern of hydrophobic residues that pack on the inside of the coiled coil and an arginine residue on the surface of the coiled coil that forms a salt bridge with a glutamic acid residue in the same polypeptide chain. In DC-SIGNR from all primates, very stable repeat units predominate, so the carbohydrate-recognition domains must be held relatively closely together. In contrast, stable repeat units are found only near the membrane in DC-SIGN. The presence of residues that disrupt tetramer formation in repeat units near the carbohydrate-recognition domains of DC-SIGN would allow these domains to splay further apart. Thus, the neck domains of DC-SIGN and DC-SIGNR can contribute to the different functions of these receptors by presenting the sugar-binding sites in different contexts.

  1. Experimental observation of further frequency upshift from dc to ac radiation converter with perpendicular dc magnetic field

    PubMed

    Higashiguchi; Yugami; Gao; Niiyama; Sasaki; Takahashi; Ito; Nishida

    2000-11-20

    A frequency upshift of a short microwave pulse is generated by the interaction between a relativistic underdense ionization front and a periodic electrostatic field with a perpendicular dc magnetic field. When the dc magnetic field is applied, further frequency upshift of 3 GHz is observed with respect to an unmagnetized case which has typically a GHz range. The radiation frequency depends on both the plasma density and the strength of the dc magnetic field, i.e., the plasma frequency and the cyclotron frequency. The frequency of the emitted radiation is in reasonable agreement with the theoretical values.

  2. Natural gas pipeline leaks across Washington, DC.

    PubMed

    Jackson, Robert B; Down, Adrian; Phillips, Nathan G; Ackley, Robert C; Cook, Charles W; Plata, Desiree L; Zhao, Kaiguang

    2014-01-01

    Pipeline safety in the United States has increased in recent decades, but incidents involving natural gas pipelines still cause an average of 17 fatalities and $133 M in property damage annually. Natural gas leaks are also the largest anthropogenic source of the greenhouse gas methane (CH4) in the U.S. To reduce pipeline leakage and increase consumer safety, we deployed a Picarro G2301 Cavity Ring-Down Spectrometer in a car, mapping 5893 natural gas leaks (2.5 to 88.6 ppm CH4) across 1500 road miles of Washington, DC. The δ(13)C-isotopic signatures of the methane (-38.2‰ ± 3.9‰ s.d.) and ethane (-36.5 ± 1.1 s.d.) and the CH4:C2H6 ratios (25.5 ± 8.9 s.d.) closely matched the pipeline gas (-39.0‰ and -36.2‰ for methane and ethane; 19.0 for CH4/C2H6). Emissions from four street leaks ranged from 9200 to 38,200 L CH4 day(-1) each, comparable to natural gas used by 1.7 to 7.0 homes, respectively. At 19 tested locations, 12 potentially explosive (Grade 1) methane concentrations of 50,000 to 500,000 ppm were detected in manholes. Financial incentives and targeted programs among companies, public utility commissions, and scientists to reduce leaks and replace old cast-iron pipes will improve consumer safety and air quality, save money, and lower greenhouse gas emissions.

  3. Tachometers Derived From a Brushless DC Motor

    NASA Technical Reports Server (NTRS)

    Howard, David E.; Smith, Dennis A.

    2007-01-01

    The upper part of the figure illustrates the major functional blocks of a direction-sensitive analog tachometer circuit based on the use of an unexcited two-phase brushless dc motor as a rotation transducer. The primary advantages of this circuit over many older tachometer circuits include the following: Its output inherently varies linearly with the rate of rotation of the shaft. Unlike some tachometer circuits that rely on differentiation of voltages with respect to time, this circuit relies on integration, which results in signals that are less noisy. There is no need for an additional shaft-angle sensor, nor is there any need to supply electrical excitation to a shaft-angle sensor. There is no need for mechanical brushes (which tend to act as sources of electrical noise). The underlying concept and electrical design are relatively simple. This circuit processes the back-electromagnetic force (back-emf) outputs of the two motor phases into a voltage directly proportional to the instantaneous rate (sign magnitude) of rotation of the shaft. The processing in this circuit effects a straightforward combination of mathematical operations leading to a final operation based on the well-known trigonometric identity (sin x)2 + (cos x)2 = 1 for any value of x. The principle of operation of this circuit is closely related to that of the tachometer circuit described in Tachometer Derived From Brushless Shaft-Angle Resolver (MFS-28845), NASA Tech Briefs, Vol. 19, No. 3 (March 1995), page 39. However, the present circuit is simpler in some respects because there is no need for sinusoidal excitation of shaftangle- resolver windings.

  4. Enhancement of Current Density by dc Electric Concentrator

    PubMed Central

    Jiang, Wei Xiang; Luo, Chen Yang; Ma, Hui Feng; Mei, Zhong Lei; Cui, Tie Jun

    2012-01-01

    We investigate a dc electric concentrator for steady current fields theoretically and experimentally. Based on the transformation electrostatics, we show that the dc concentrator can focus electric currents into the central concentrated region and enhance the electric field and current density. Outside the concentrator, the current lines are distributed as the same as those in a homogeneous conducting material. Hence, such a dc electric concentrator has no impact on other external devices. Using the analogy between electrically conducting materials and resistor networks, we design, fabricate, and test a dc concentrator using the circuit theory. The measured results agree very well with the theoretical predictions and numerical simulations, demonstrating the perfect concentrating performance. PMID:23233875

  5. 24. POWER ROOM INTERIOR, DC WESTINGHOUSE EXCITER UNIT INCLUDING A ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. POWER ROOM INTERIOR, DC WESTINGHOUSE EXCITER UNIT INCLUDING A SHUNT WOUND GENERATOR AND FIELD RHEOSTAT, 1500 RPM, 85 VNL TO 15 VOLT 90 SFL - Death Valley Ranch, Power House, Death Valley Junction, Inyo County, CA

  6. Radiofrequency amplifier based on a dc superconducting quantum interference device

    DOEpatents

    Hilbert, Claude; Martinis, John M.; Clarke, John

    1986-01-01

    A low noise radiofrequency amplifier (10), using a dc SQUID (superconducting quantum interference device) as the input amplifying element. The dc SQUID (11) and an input coil (12) are maintained at superconductivity temperatures in a superconducting shield (13), with the input coil (12) inductively coupled to the superconducting ring (17) of the dc SQUID (11). A radiofrequency signal from outside the shield (13) is applied to the input coil (12), and an amplified radiofrequency signal is developed across the dc SQUID ring (17) and transmitted to exteriorly of the shield (13). A power gain of 19.5.+-.0.5 dB has been achieved with a noise temperature of 1.0.+-.0.4 K. at a frequency of 100 MHz.

  7. Radiofrequency amplifier based on a dc superconducting quantum interference device

    DOEpatents

    Hilbert, C.; Martinis, J.M.; Clarke, J.

    1984-04-27

    A low noise radiofrequency amplifer, using a dc SQUID (superconducting quantum interference device) as the input amplifying element. The dc SQUID and an input coil are maintained at superconductivity temperatures in a superconducting shield, with the input coil inductively coupled to the superconducting ring of the dc SQUID. A radiofrequency signal from outside the shield is applied to the input coil, and an amplified radiofrequency signal is developed across the dc SQUID ring and transmitted to exteriorly of the shield. A power gain of 19.5 +- 0.5 dB has been achieved with a noise temperature of 1.0 +- 0.4 K at a frequency of 100 MHz.

  8. Dc to ac converter operates efficiently at low input voltages

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Self-oscillating dc to ac converter with transistor switching to produce a square wave output is used for low and high voltage power sources. The converter has a high efficiency throughout a wide range of loads.

  9. DC motor proportional control system for orthotic devices

    NASA Technical Reports Server (NTRS)

    Blaise, H. T.; Allen, J. R.

    1972-01-01

    Multi-channel proportional control system for operation of dc motors for use with externally-powered orthotic arm braces is described. Components of circuitry and principles of operation are described. Schematic diagram of control circuit is provided.

  10. Links Related to Anacostia Watershed (Washington, DC/Maryland)

    EPA Pesticide Factsheets

    Anacostia Watershed (Washington, DC/Maryland) of the Urban Waters Federal Partnership (UWFP) reconnects urban communities with their waterways by improving coordination among federal agencies and collaborating with community-led efforts.

  11. Description and Status of the DC Lightning Mapping Array

    NASA Technical Reports Server (NTRS)

    Blakeslee, Richard; Rudlosky, Scott D.; Bailey, Jeffrey C.; Hall, John M.; Goodman, Steven J.; Zubrick, Steven; Krehbiel, Paul

    2011-01-01

    The DC Lightning Mapping Array (DC LMA) centered on the Washington, DC metro region has been in operation since 2006. During that time the DC LMA has provided real time data to regional National Weather Service (NSF) Sterling, VA forecast office for operations support and the NOAA Meteorological Development Laboratory (MDL) for new product development and assessment. Data from this network (as well as other from other LMA systems) are now being used to create proxy Geostationary Lightning Mapper (GLM) data sets for GOES-R risk reduction and algorithm development activities. In addition, since spring 2009 data are provided to the Storm Prediction Center in support of Hazardous Weather Testbed and GOES-R Proving Ground activities during the Spring Program. Description, status and plans will be discussed.

  12. Meetings & Events about Anacostia Watershed (Washington, DC/Maryland)

    EPA Pesticide Factsheets

    Anacostia Watershed (Washington, DC/Maryland) of the Urban Waters Federal Partnership (UWFP) reconnects urban communities with their waterways by improving coordination among federal agencies and collaborating with community-led efforts.

  13. RadNet Air Data From Washington, DC

    EPA Pesticide Factsheets

    This page presents radiation air monitoring and air filter analysis data for Washington, DC from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  14. TRIANGLE-SHAPED DC CORONA DISCHARGE DEVICE FOR MOLECULAR DECOMPOSITION

    EPA Science Inventory

    The paper discusses the evaluation of electrostatic DC corona discharge devices for the application of molecular decomposition. A point-to-plane geometry corona device with a rectangular cross section demonstrated low decomposition efficiencies in earlier experimental work. The n...

  15. 21 CFR 82.2051 - Lakes (Ext. D&C).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Externally Applied Drugs and Cosmetics § 82.2051 Lakes (Ext. D&C...) Specifications. Ether extracts, not more than 0.5 percent. Soluble chlorides and sulfates (as sodium salts),...

  16. 21 CFR 82.2051 - Lakes (Ext. D&C).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Externally Applied Drugs and Cosmetics § 82.2051 Lakes (Ext. D&C...) Specifications. Ether extracts, not more than 0.5 percent. Soluble chlorides and sulfates (as sodium salts),...

  17. 21 CFR 82.2051 - Lakes (Ext. D&C).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Externally Applied Drugs and Cosmetics § 82.2051 Lakes (Ext. D&C...) Specifications. Ether extracts, not more than 0.5 percent. Soluble chlorides and sulfates (as sodium salts),...

  18. 21 CFR 82.2051 - Lakes (Ext. D&C).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Externally Applied Drugs and Cosmetics § 82.2051 Lakes (Ext. D&C...) Specifications. Ether extracts, not more than 0.5 percent. Soluble chlorides and sulfates (as sodium salts),...

  19. 21 CFR 82.2051 - Lakes (Ext. D&C).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Externally Applied Drugs and Cosmetics § 82.2051 Lakes (Ext. D&C...) Specifications. Ether extracts, not more than 0.5 percent. Soluble chlorides and sulfates (as sodium salts),...

  20. Design of Energy Storage Reactors for Dc-To-Dc Converters. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Chen, D. Y.

    1975-01-01

    Two methodical approaches to the design of energy-storage reactors for a group of widely used dc-to-dc converters are presented. One of these approaches is based on a steady-state time-domain analysis of piecewise-linearized circuit models of the converters, while the other approach is based on an analysis of the same circuit models, but from an energy point of view. The design procedure developed from the first approach includes a search through a stored data file of magnetic core characteristics and results in a list of usable reactor designs which meet a particular converter's requirements. Because of the complexity of this procedure, a digital computer usually is used to implement the design algorithm. The second approach, based on a study of the storage and transfer of energy in the magnetic reactors, leads to a straightforward design procedure which can be implemented with hand calculations. An equation to determine the lower-bound volume of workable cores for given converter design specifications is derived. Using this computer lower-bound volume, a comparative evaluation of various converter configurations is presented.

  1. Analysis of a transformer-less, multi-level DC-DC converter for HVDC operation

    SciTech Connect

    Karady, G.G.; Devarajan, S.

    1998-12-31

    HVDC systems require DC step up and DC step down units. The traditional approach is the application of twelve-pulse thyristor bridges with transformers. The developments of fast switching IGBT devices permit the development of transformer-less, multi-level converters. A multi-level circuit was suggested by Limpaecher. This paper presents a detailed simulation of the proposed circuit together with the analysis of its performance. The converter consists of a set of capacitors, air core inductors and solid state switches arranged in a ladder network. In the step-up mode, the closing of solid state switches resonantly charges the capacitors in parallel through an air-cored inductor. Then solid state switches resonantly charges the capacitors in parallel through an air-cored inductor. Then solid state switches connect the capacitors in series and discharge them through an air-core inductor to the load. In the step-down mode the capacitors are charged in series and discharged in parallel. The circuit has three modes of operation in each cycle: charge, inversion, and discharge. The circuit operation is analyzed in each mode using SPICE simulations. The selection of the components is discussed and output voltage regulation is analyzed. The results show that the proposed circuit promises significant reduction of losses, because of the zero current switching. The investment cost is reduced because of the elimination of transformers.

  2. High power density dc-to-dc converters for aerospace applications

    NASA Technical Reports Server (NTRS)

    Divan, Deepakraj M.

    1990-01-01

    Three dc-to-dc converter topologies aimed at high-power high-frequency applications are introduced. Major system parasitics, namely, the leakage inductance of the transformer and the device output capacitance are efficiently utilized. Of the three circuits, the single-phase and three-phase versions of the dual active bridge topology demonstrate minimal stresses, better utilization of the transformer, bidirectional, and buck-boost modes of operation. All circuits operate at a constant switching frequency, thus simplifying design of the reactive elements. The power transfer characteristics and soft-switching regions on the Vout-Iout plane are identified. Two coaxial transformers with different cross-sections were built for a rating of 50 kVA. Based on the single-phase dual active bridge topology, a 50 kW, 50 kHz converter operating at an input voltage of 200 Vdc and an output voltage of 1600 Vdc was fabricated. Characteristics of current-fed output make the dual active bridge topologies amenable to paralleling and hence extension to megawatt power levels. Projections to a 1 MW system operating from a 500 Vdc input, at an output voltage of 10 kVdc and a switching frequency of 50 kHz, using MOS-controlled thyristors, coaxially wound transformers operating at three times the present current density with cooling, and multilayer ceramic capacitors, suggests an overall power density of 0.075 to 0.08 kg/kW and an overall efficiency of 96 percent.

  3. An Optimal Current Observer for Predictive Current Controlled Buck DC-DC Converters

    PubMed Central

    Min, Run; Chen, Chen; Zhang, Xiaodong; Zou, Xuecheng; Tong, Qiaoling; Zhang, Qiao

    2014-01-01

    In digital current mode controlled DC-DC converters, conventional current sensors might not provide isolation at a minimized price, power loss and size. Therefore, a current observer which can be realized based on the digital circuit itself, is a possible substitute. However, the observed current may diverge due to the parasitic resistors and the forward conduction voltage of the diode. Moreover, the divergence of the observed current will cause steady state errors in the output voltage. In this paper, an optimal current observer is proposed. It achieves the highest observation accuracy by compensating for all the known parasitic parameters. By employing the optimal current observer-based predictive current controller, a buck converter is implemented. The converter has a convergently and accurately observed inductor current, and shows preferable transient response than the conventional voltage mode controlled converter. Besides, costs, power loss and size are minimized since the strategy requires no additional hardware for current sensing. The effectiveness of the proposed optimal current observer is demonstrated experimentally. PMID:24854061

  4. Washington DC Area Computer Aided Surgery Society Monthly Meetings

    DTIC Science & Technology

    2009-03-01

    05-1-0072 TITLE: Washington DC Area Computer Aided Surgery Society Monthly Meetings PRINCIPAL INVESTIGATOR: Kevin R. Cleary, Ph.D...Feb 2005-21 Feb 2009 4. Title and Subtitle Washington DC Area Computer Aided Surgery Society Monthly Meetings 5. Award Number W81XWH-05-1-0072...Area Computer-Aided Surgery Society (WashCAS) has become the major vehicle in the Washington/Baltimore area for exploring the issues in the emerging

  5. Low-to-Medium Power Single Chip Digital Controlled DC-DC Regulator for Point-of-Load Applications

    NASA Technical Reports Server (NTRS)

    Adell, Philippe C. (Inventor); Bakkaloglu, Bertan (Inventor); Vermeire, Bert (Inventor); Liu, Tao (Inventor)

    2015-01-01

    A DC-DC converter for generating a DC output voltage includes: a digitally controlled pulse width modulator (DPWM) for controlling a switching power stage to supply a varying voltage to an inductor; and a digital voltage feedback circuit for controlling the DPWM in accordance with a feedback voltage corresponding to the DC output voltage, the digital voltage feedback circuit including: a first voltage controlled oscillator for converting the feedback voltage into a first frequency signal and to supply the first frequency signal to a first frequency discriminator; a second voltage controlled oscillator for converting a reference voltage into a second frequency signal and to supply the second frequency signal to a second frequency discriminator; a digital comparator for comparing digital outputs of the first and second frequency discriminators and for outputting a digital feedback signal; and a controller for controlling the DPWM in accordance with the digital feedback signal.

  6. Digital computer simulation of inductor-energy-storage dc-to-dc converters with closed-loop regulators

    NASA Technical Reports Server (NTRS)

    Ohri, A. K.; Owen, H. A.; Wilson, T. G.; Rodriguez, G. E.

    1974-01-01

    The simulation of converter-controller combinations by means of a flexible digital computer program which produces output to a graphic display is discussed. The procedure is an alternative to mathematical analysis of converter systems. The types of computer programming involved in the simulation are described. Schematic diagrams, state equations, and output equations are displayed for four basic forms of inductor-energy-storage dc to dc converters. Mathematical models are developed to show the relationship of the parameters.

  7. A 1.6-kW, 110-kHz dc-dc converter optimized for IGBT's

    NASA Technical Reports Server (NTRS)

    Chen, Keming; Stuart, Thomas A.

    1993-01-01

    A full bridge dc-dc converter using a zero-current and zero-voltage switching technique is described. This circuit utilizes the characteristics of the IGBT to achieve power and frequency combinations that are much higher than previously reported for this device. Experimental results are included for a 1.6-kW, 110-kHz converter with 95 percent efficiency.

  8. A Low-Cost Soft-Switched DC/DC Converter for Solid-Oxide Fuel Cells

    SciTech Connect

    Jason Lai

    2009-03-03

    A highly efficient DC to DC converter has been developed for low-voltage high-current solid oxide fuel cells. The newly developed 'V6' converter resembles what has been done in internal combustion engine that split into multiple cylinders to increase the output capacity without having to increase individual cell size and to smooth out the torque with interleaving operation. The development was started with topology overview to ensure that all the DC to DC converter circuits were included in the study. Efficiency models for different circuit topologies were established, and computer simulations were performed to determine the best candidate converter circuit. Through design optimization including topology selection, device selection, magnetic component design, thermal design, and digital controller design, a bench prototype rated 5-kW, with 20 to 50V input and 200/400V output was fabricated and tested. Efficiency goal of 97% was proven achievable through hardware experiment. This DC to DC converter was then modified in the later stage to converter 35 to 63 V input and 13.8 V output for automotive charging applications. The complete prototype was tested at Delphi with their solid oxide fuel cell test stand to verify the performance of the modified DC to DC converter. The output was tested up to 3-kW level, and the efficiency exceeded 97.5%. Multiple-phase interleaving operation design was proved to be reliable and ripple free at the output, which is desirable for the battery charging. Overall this is a very successful collaboration project between the SECA Core Technology Team and Industrial Team.

  9. A High Efficiency DC-DC Converter Topology Suitable for Distributed Large Commercial and Utility Scale PV Systems

    SciTech Connect

    Agamy, Mohammed S; Harfman-Todorovic, Maja; Elasser, Ahmed; Steigerwald, Robert L; Sabate, Juan A; Chi, Song; McCann, Adam J; Zhang, Li; Mueller, Frank

    2012-09-01

    In this paper a DC-DC power converter for distributed photovoltaic plant architectures is presented. The proposed converter has the advantages of simplicity, high efficiency, and low cost. High efficiency is achieved by having a portion of the input PV power directly fed forward to the output without being processed by the converter. The operation of this converter also allows for a simplified maximum power point tracker design using fewer measurements

  10. Fast-response free-running dc-to-dc converter employing a state-trajectory control law

    NASA Technical Reports Server (NTRS)

    Huffman, S. D.; Burns, W. W., III; Wilson, T. G.; Owen, H. A., Jr.

    1977-01-01

    A recently proposed state-trajectory control law for a family of energy-storage dc-to-dc converters has been implemented for the voltage step-up configuration. Two methods of realization are discussed; one employs a digital processor and the other uses analog computational circuits. Performance characteristics of experimental voltage step-up converters operating under the control of each of these implementations are reported and compared to theoretical predictions and computer simulations.

  11. 1. WASHINGTON TERMINAL COMPANY: UNION STATION. WASHINGTON, D.C. Sec. 1201, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. WASHINGTON TERMINAL COMPANY: UNION STATION. WASHINGTON, D.C. Sec. 1201, MP 137.00. (See HAER No. DC-1 for documentation on Union Station Power Plant.) - Northeast Railroad Corridor, Amtrak Route between Union Station & DC/MD State Line, Washington, District of Columbia, DC

  12. 75 FR 1406 - National Mall and Memorial Parks, Washington, DC; Notice of Availability of an Environmental...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-11

    ... National Park Service National Mall and Memorial Parks, Washington, DC; Notice of Availability of an... Mall Plan, within the National Mall and Memorial Parks in Washington, DC. The National Mall Plan is a..., SW., Washington, DC 20024, and at local libraries around Washington, DC. SUPPLEMENTARY...

  13. 77 FR 74347 - Prevailing Rate Systems; Abolishment of the Washington, DC, Special Wage Schedule for Printing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-14

    ... RIN 3206-AM59 Prevailing Rate Systems; Abolishment of the Washington, DC, Special Wage Schedule for.... Office of Personnel Management is issuing a final rule to abolish the Washington, DC, Federal Wage System... employees in the Washington, DC, wage area will now be paid from the regular Washington, DC,...

  14. 77 FR 31341 - Application To Export Electric Energy; DC Energy, LLC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-25

    ... Application To Export Electric Energy; DC Energy, LLC AGENCY: Office of Electricity Delivery and Energy Reliability, DOE. ACTION: Notice of Application. SUMMARY: DC Energy, LLC (DC Energy) has applied to renew its... of Energy, 1000 Independence Avenue SW., Washington, DC 20585-0350. Because of delays in...

  15. A study of DC-DC converters with MCT's for arcjet power supplies

    NASA Technical Reports Server (NTRS)

    Stuart, Thomas A.

    1994-01-01

    Many arcjet DC power supplies use PWM full bridge converters with large arrays of parallel FET's. This report investigates an alternative supply using a variable frequency series resonant converter with small arrays of parallel MCT's (metal oxide semiconductor controlled thyristors). The reasons for this approach are to: increase reliability by reducing the number of switching devices; and decrease the surface mounting area of the switching arrays. The variable frequency series resonant approach is used because the relatively slow switching speed of the MCT precludes the use of PWM. The 10 kW converter operated satisfactorily with an efficiency of over 91 percent. Test results indicate this efficiency could be increased further by additional optimization of the series resonant inductor.

  16. Structural characterization of the DC-SIGN-Lewis(X) complex.

    PubMed

    Pederson, Kari; Mitchell, Daniel A; Prestegard, James H

    2014-09-09

    Dendritic cell-specific intracellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) is a C-type lectin highly expressed on the surface of antigen-presenting dendritic cells. DC-SIGN mediates interactions among dendritic cells, pathogens, and a variety of epithelia, myeloid cells, and endothelia by binding to high mannose residues on pathogenic invaders or fucosylated residues on the membranes of other immune cells. Although these interactions are normally beneficial, they can also contribute to disease. The structural characterization of binding geometries is therefore of interest as a basis for the construction of mimetics that can mediate the effects of abnormal immune response. Here, we report the structural characteristics of the interaction of the DC-SIGN carbohydrate recognition domain (CRD) with a common fucosylated entity, the Lewis(X) trisaccharide (Le(X)), using NMR methods. Titration of the monomeric DC-SIGN CRD with Le(X) monitored by 2D NMR revealed significant perturbations of DC-SIGN cross-peak positions in (1)H-(15)N heteronuclear single quantum coherence (HSQC) spectra and identified residues near the binding site. Additionally, saturation transfer difference (STD) and transferred nuclear Overhauser effect (trNOE) NMR experiments, using a tetrameric form of DC-SIGN, identified binding epitopes and bound conformations of the Le(X) ligand. The restraints derived from these multiple experiments were used to generate models for the binding of Le(X) to the DC-SIGN CRD. Ranking of the models based on the fit of model-based simulations of the trNOE data and STD buildup curves suggested conformations distinct from those seen in previous crystal structures. The new conformations offer insight into how differences between binding of Lewis(X) and mannose-terminated saccharides may be propagated.

  17. Human DC-SIGN binds specific human milk glycans.

    PubMed

    Noll, Alexander J; Yu, Ying; Lasanajak, Yi; Duska-McEwen, Geralyn; Buck, Rachael H; Smith, David F; Cummings, Richard D

    2016-05-15

    Human milk glycans (HMGs) are prebiotics, pathogen receptor decoys and regulators of host physiology and immune responses. Mechanistically, human lectins (glycan-binding proteins, hGBP) expressed by dendritic cells (DCs) are of major interest, as these cells directly contact HMGs. To explore such interactions, we screened many C-type lectins and sialic acid-binding immunoglobulin-like lectins (Siglecs) expressed by DCs for glycan binding on microarrays presenting over 200 HMGs. Unexpectedly, DC-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN) showed robust binding to many HMGs, whereas other C-type lectins failed to bind, and Siglec-5 and Siglec-9 showed weak binding to a few glycans. By contrast, most hGBP bound to multiple glycans on other microarrays lacking HMGs. An α-linked fucose residue was characteristic of HMGs bound by DC-SIGN. Binding of DC-SIGN to the simple HMGs 2'-fucosyl-lactose (2'-FL) and 3-fucosyl-lactose (3-FL) was confirmed by flow cytometry to beads conjugated with 2'-FL or 3-FL, as well as the ability of the free glycans to inhibit DC-SIGN binding. 2'-FL had an IC50 of ∼1 mM for DC-SIGN, which is within the physiological concentration of 2'-FL in human milk. These results demonstrate that DC-SIGN among the many hGBP expressed by DCs binds to α-fucosylated HMGs, and suggest that such interactions may be important in influencing immune responses in the developing infant.

  18. Radiation effects in power converters: Design of a radiation hardened integrated switching DC/DC converter

    NASA Astrophysics Data System (ADS)

    Adell, Philippe

    . This design is the first radiation-hardened DC/DC power converter in this power range that integrates the switch, controller, and rectifier. The design has been fabricated, simulated and tested.

  19. Fast-response free-running frequency-stabilized dc-to-dc converter employing a state plane-trajectory control law

    NASA Technical Reports Server (NTRS)

    Huffman, S. D.; Burns, W. W., III; Wilson, T. G.; Owen, H. A., Jr.

    1976-01-01

    Implementations of a state-plane-trajectory control law for energy storage dc-to-dc converters are presented. Performance characteristics of experimental voltage step-up converter systems employing these implementations are reported and compared to theoretical predictions.

  20. Recording of focal direct current (DC) changes in the human cerebral cortex using refined non-invasive DC-EEG methodology.

    PubMed

    Leistner, Stefanie; Scheer, Hans-Juergen; Sander, Tilmann; Burghoff, Martin; Trahms, Lutz; Curio, Gabriel; Mackert, Bruno-Marcel

    2007-02-01

    A non-invasive DC electroencephalographic (DC-EEG) method was developed to record and analyze focal low-frequency (<0.1 Hz) DC changes in the human cerebral cortex. A simple repetitive finger-movement task was used as a physiological activation paradigm. DC-EEG amplitudes were recorded using a custom-made DC amplifier with automatic offset correction. A total of 16 standard Ag/AgCl electrodes covered the left primary motor cortex. In three of six subjects, reliable focal motor-related DC-EEG shifts over the hand cortex were monitored. This study demonstrates that refined DC-EEG recording and data analysis procedures allow non-invasive recording of low-frequency and low-amplitude focal cortical changes in humans. An important clinical perspective of this technology is the detection of stroke-associated cortical DC activity.

  1. Symmetrical dynamics of peak current-mode and valley current-mode controlled switching dc-dc converters with ramp compensation

    NASA Astrophysics Data System (ADS)

    Zhou, Guo-Hua; Xu, Jian-Ping; Bao, Bo-Cheng; Jin, Yan-Yan

    2010-06-01

    The discrete iterative map models of peak current-mode (PCM) and valley current-mode (VCM) controlled buck converters, boost converters, and buck-boost converters with ramp compensation are established and their dynamical behaviours are investigated by using the operation region, parameter space map, bifurcation diagram, and Lyapunov exponent spectrum. The research results indicate that ramp compensation extends the stable operation range of the PCM controlled switching dc-dc converter to D > 0.5 and that of the VCM controlled switching dc-dc converter to D < 0.5. Compared with PCM controlled switching dc-dc converters with ramp compensation, VCM controlled switching dc-dc converters with ramp compensation exhibit interesting symmetrical dynamics. Experimental results are given to verify the analysis results in this paper.

  2. 75 FR 2831 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, and MD-10-10F...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-19

    ... Corporation Model DC- 10-10, DC-10-10F, and MD-10-10F Airplanes AGENCY: Federal Aviation Administration (FAA... directive (AD) for certain McDonnell Douglas Model DC-10-10, DC-10-10F, and MD-10-10F airplanes. This... corrective actions if necessary. This proposed AD results from a report of three instances of Model...

  3. Pseudo-Mannosylated DC-SIGN Ligands as Immunomodulants.

    PubMed

    Berzi, Angela; Ordanini, Stefania; Joosten, Ben; Trabattoni, Daria; Cambi, Alessandra; Bernardi, Anna; Clerici, Mario

    2016-10-13

    DC-SIGN, a C-type lectin mainly expressed by DCs, mediates antigen uptake and can induce specific immune responses, depending on the ligand involved. Owing to these properties, DC-SIGN is an attracting target for approaches aimed at tailoring the immune response towards specific immunologic outcomes. A multivalent DC-SIGN ligand (Polyman26), containing at its core a fluorescent "rod-like" spacer and able to inhibit DC-SIGN mediated HIV infection in nanomolar concentration, has been recently developed by our group. We investigated the internalization pattern and the ability of Polyman26 to elicit innate immune responses. Results obtained by confocal microscopy indicate that Polyman26 is internalized by DCs via receptor- mediated endocytosis and is then routed to endolysosomal compartments, thus being presented together with MHC class II molecules, with important implications for the development of vaccines. Moreover, Polyman26 up-regulated the production of β-chemokines and pro-inflammatory cytokines (including IL-1β, IL-6, IL-12, and TNFα) as well as the expression of TLR9 and CD40L. These results indicate that glycomimetic DC-SIGN ligands should be further investigated and suggest that these compounds could be used to differentially stimulate immune responses.

  4. Quasi-DC electrical discharge characterization in a supersonic flow

    NASA Astrophysics Data System (ADS)

    Houpt, Alec; Hedlund, Brock; Leonov, Sergey; Ombrello, Timothy; Carter, Campbell

    2017-04-01

    A Quasi-DC (Q-DC) electrical discharge generates a highly transient filamentary plasma in high-speed airflow. Major specific properties of this type of discharge are realized due to a strong coupling of the plasma to the moving gas. The plasma, supplied by a DC voltage waveform, demonstrates a pulsed-periodic pattern of dynamics significantly affecting the flow structure. In this study, the dynamics and plasma parameters of the Q-DC discharge are analyzed in the Supersonic Test Rig (SBR-50) at the University of Notre Dame at Mach number M = 2, stagnation pressure P 0 = (0.9-2.6) × 105 Pa, stagnation temperature T 0 = 300 K, unit Reynolds number ReL = 7-25 × 106 m-1, and plasma power W pl = 3-21 kW. The plasma parameters are measured with current-voltage probes and optical emission spectroscopy. An unsteady pattern of interaction is depicted by high-speed image capturing. The result of the plasma-flow interaction is characterized by means of pressure measurements and schlieren visualization. It is considered that the Q-DC discharge may be employed for active control of duct-driven flows, cavity-based flow, and for effective control of shock wave-boundary layer interaction.

  5. DC Microgrids Scoping Study. Estimate of Technical and Economic Benefits

    SciTech Connect

    Backhaus, Scott N.; Swift, Gregory William; Chatzivasileiadis, Spyridon; Tschudi, William; Glover, Steven; Starke, Michael; Wang, Jianhui; Yue, Meng; Hammerstrom, Donald

    2015-03-23

    Microgrid demonstrations and deployments are expanding in US power systems and around the world. Although goals are specific to each site, these microgrids have demonstrated the ability to provide higher reliability and higher power quality than utility power systems and improved energy utilization. The vast majority of these microgrids are based on AC power transfer because this has been the traditionally dominant power delivery scheme. Independently, manufacturers, power system designers and researchers are demonstrating and deploying DC power distribution systems for applications where the end-use loads are natively DC, e.g., computers, solid-state lighting, and building networks. These early DC applications may provide higher efficiency, added flexibility, reduced capital costs over their AC counterparts. Further, when onsite renewable generation, electric vehicles and storage systems are present, DC-based microgrids may offer additional benefits. Early successes from these efforts raises a question - can a combination of microgrid concepts and DC distribution systems provide added benefits beyond what has been achieved individually?

  6. Pseudo-Mannosylated DC-SIGN Ligands as Immunomodulants

    PubMed Central

    Berzi, Angela; Ordanini, Stefania; Joosten, Ben; Trabattoni, Daria; Cambi, Alessandra; Bernardi, Anna; Clerici, Mario

    2016-01-01

    DC-SIGN, a C-type lectin mainly expressed by DCs, mediates antigen uptake and can induce specific immune responses, depending on the ligand involved. Owing to these properties, DC-SIGN is an attracting target for approaches aimed at tailoring the immune response towards specific immunologic outcomes. A multivalent DC-SIGN ligand (Polyman26), containing at its core a fluorescent “rod-like” spacer and able to inhibit DC-SIGN mediated HIV infection in nanomolar concentration, has been recently developed by our group. We investigated the internalization pattern and the ability of Polyman26 to elicit innate immune responses. Results obtained by confocal microscopy indicate that Polyman26 is internalized by DCs via receptor- mediated endocytosis and is then routed to endolysosomal compartments, thus being presented together with MHC class II molecules, with important implications for the development of vaccines. Moreover, Polyman26 up-regulated the production of β-chemokines and pro-inflammatory cytokines (including IL-1β, IL-6, IL-12, and TNFα) as well as the expression of TLR9 and CD40L. These results indicate that glycomimetic DC-SIGN ligands should be further investigated and suggest that these compounds could be used to differentially stimulate immune responses. PMID:27734954

  7. Results of winglet development studies for DC-10 derivatives

    NASA Technical Reports Server (NTRS)

    Shollenberger, C. A.; Humphreys, J. W.; Heiberger, F. S.; Pearson, R. M.

    1983-01-01

    The results of investigations into the application of winglets to the DC-10 aircraft are presented. The DC-10 winglet configuration was developed and its cruise performance determined in a previous investigation. This study included high speed and low speed wind tunnel tests to evaluate aerodynamic characteristics, and a subsonic flutter wind tunnel test with accompanying analysis and evaluation of results. Additionally, a configuration integration study employed the results of the wind tunnel studies to determine the overall impact of the installation of winglets on the DC-10 aircraft. Conclusions derived from the high speed and low speed tests indicate that the winglets had no significant effects on the DC-10 stability characteristics or high speed buffet. It was determined that winglets had a minimal effect on aircraft lift characteristics and improved the low speed aircraft drag under high lift conditions. The winglets affected the DC-10 flutter characteristics by reducing the flutter speed of the basic critical mode and introducing a new critical mode involving outer wing torsion and longitudinal bending. The overall impact of winglets was determined to be of sufficient benefit to merit flight evaluation.

  8. DC artifact correction for arbitrary phase-cycling sequence.

    PubMed

    Han, Paul Kyu; Park, HyunWook; Park, Sung-Hong

    2017-05-01

    In magnetic resonance imaging (MRI), a non-zero offset in the receiver baseline signal during acquisition results in a bright spot or a line artifact in the center of the image known as a direct current (DC) artifact. Several methods have been suggested in the past for the removal or correction of DC artifacts in MR images, however, these methods cannot be applied directly when a specific phase-cycling technique is used in the imaging sequence. In this work, we proposed a new, simple technique that enables correction of DC artifacts for any arbitrary phase-cycling imaging sequences. The technique is composed of phase unification, DC offset estimation and correction, and phase restoration. The feasibility of the proposed method was demonstrated via phantom and in vivo experiments with a multiple phase-cycling balanced steady-state free precession (bSSFP) imaging sequence. Results showed successful removal of the DC artifacts in images acquired using bSSFP with phase-cycling angles of 0°, 90°, 180°, and 270°, indicating potential feasibility of the proposed method to any imaging sequence with arbitrary phase-cycling angles.

  9. IMPLEMENTING THE DC MODE IN COSMOLOGICAL SIMULATIONS WITH SUPERCOMOVING VARIABLES

    SciTech Connect

    Gnedin, Nickolay Y.; Kravtsov, Andrey V.; Rudd, Douglas H. E-mail: andrey@oddjob.uchicago.edu

    2011-06-01

    As emphasized by previous studies, proper treatment of the density fluctuation on the fundamental scale of a cosmological simulation volume-the {sup D}C mode{sup -}is critical for accurate modeling of spatial correlations on scales {approx}> 10% of simulation box size. We provide further illustration of the effects of the DC mode on the abundance of halos in small boxes and show that it is straightforward to incorporate this mode in cosmological codes that use the 'supercomoving' variables. The equations governing evolution of dark matter and baryons recast with these variables are particularly simple and include the expansion factor, and hence the effect of the DC mode, explicitly only in the Poisson equation.

  10. Magnetoencephalography using a Multilayer hightc DC SQUID Magnetometer

    NASA Astrophysics Data System (ADS)

    Faley, M. I.; Poppe, U.; Borkowski, R. E. Dunin; Schiek, M.; Boers, F.; Chocholacs, H.; Dammers, J.; Eich, E.; Shah, N. J.; Ermakov, A. B.; Slobodchikov, V. Yu.; Maslennikov, Yu. V.; Koshelets, V. P.

    We describe tests of the use of a multilayer highTc DC SQUID magnetometer for magnetoencephalography (MEG) and compare our measurements with results obtained using a lowTc SQUID sensor. The integration of bias reversal readout electronics for highTc DC SQUID magnetometry into a commercial MEG data acquisition system is demonstrated. Results of measurements performed on a salinefilled head phantom are shown and the detection of an auditory evoked magnetic response of the human cortex elicited by a stimulus is illustrated. Future modifications of highTc DC SQUID sensors for applications in MEG, in order to reach a resolution of 1 fT/√Hz at 77.5 K over a wide frequency band, are outlined.

  11. Photovoltaic-wind hybrid system for permanent magnet DC motor

    NASA Astrophysics Data System (ADS)

    Nasir, M. N. M.; Lada, M. Y.; Baharom, M. F.; Jaafar, H. I.; Ramani, A. N.; Sulaima, M. F.

    2015-05-01

    Hybrid system of Photovoltaic (PV) - Wind turbine (WT) generation has more advantages and reliable compared to PV or wind turbine system alone. The aim of this paper is to model and design hybrid system of PV-WT supplying 100W permanent-magnet dc motor. To achieve the objective, both of PV and WT are connected to converter in order to get the same source of DC supply. Then both sources were combined and straightly connected to 100W permanent magnet dc motor. All the works in this paper is only applied in circuit simulator by using Matlab Simulink. The output produced from each converter is expected to be suit to the motor specification. The output produced from each renewable energy system is as expected to be high as it can support the motor if one of them is breakdown

  12. Thermal conductivity measurement of thin films by a dc method.

    PubMed

    Yang, Junyou; Zhang, Jiansheng; Zhang, Hui; Zhu, Yunfeng

    2010-11-01

    A dc method, which needs no complex numerical calculation and expensive hardware configuration, was developed to measure the cross-plane thermal conductivity of thin films in this paper. Two parallel metallic heaters, which were deposited on different parts of the sample, serve simultaneously as the heaters and temperature sensors during the measurement. A direct current was flowed through the same two metallic strips to heat the thin-film sample. The heating power and the heater's temperature were obtained by a data acquisition device, and the thermal conductivity of thin film was calculated. To verify the validity of the dc method, several SiO(2) films with different thicknesses were deposited on Si wafers, respectively, and their thermal conductivities were measured by both the dc method and 3ω method. The results of two methods are in good agreement within an acceptable error, and they are also inconsistent with some of previously published data.

  13. DESIGN OF A DC/RF PHOTOELECTRON GUN.

    SciTech Connect

    YU,D.NEWSHAM,Y.SMIRONOV,A.YU,J.SMEDLEY,J.SRINIVASAN RAU,T.LEWELLEN,J.ZHOLENTS,A.

    2003-05-12

    An integrated dc/rf photoelectron gun produces a low-emittance beam by first rapidly accelerating electrons at a high gradient during a short ({approx}1 ns), high-voltage pulse, and then injecting the electrons into an rf cavity for subsequent acceleration. Simulations show that significant improvement of the emittance appears when a high field ({approx} 0.5-1 GV/m) is applied to the cathode surface. An adjustable dc gap ({le} 1 mm) which can be integrated with an rf cavity is designed for initial testing at the Injector Test Stand at Argonne National Laboratory using an existing 70-kV pulse generator. Plans for additional experiments of an integrated dc/rf gun with a 250-kV pulse generator are being made.

  14. Nuclear magnetic resonance experiments with dc SQUID amplifiers

    SciTech Connect

    Heaney, M.B. . Dept. of Physics Lawrence Berkeley Lab., CA )

    1990-11-01

    The development and fabrication of dc SQUIDs (Superconducting QUantum Interference Devices) with Nb/Al{sub 2}O{sub 3}/Nb Josephson junctions is described. A theory of the dc SQUID as a radio-frequency amplifier is presented, with an optimization strategy that accounts for the loading and noise contributions of the postamplifier and maximizes the signal-to-noise ratio of the total system. The high sensitivity of the dc SQUID is extended to high field NMR. A dc SQUID is used as a tuned radio-frequency amplifier to detect pulsed nuclear magnetic resonance at 32 MHz from a metal film in a 3.5 Tesla static field. A total system noise temperature of 11 K has been achieved, at a bath temperature of 4.2 K. The minimum number of nuclear Bohr magnetons observable from a free precession signal after a single pulse is about 2 {times} 10{sup 17} in a bandwidth of 25 kHz. In a separate experiment, a dc SQUID is used as a rf amplifier in a NQR experiment to observe a new resonance response mechanism. The net electric polarization of a NaClO{sub 3} crystal due to the precessing electric quadrupole moments of the Cl nuclei is detected at 30 MHz. The sensitivity of NMR and NQR spectrometers using dc SQUID amplifiers is compared to the sensitivity of spectrometers using conventional rf amplifiers. A SQUID-based spectrometer has a voltage sensitivity which is comparable to the best achieved by a FET-based spectrometer, at these temperatures and operating frequencies.

  15. Spatial location weighted optimization scheme for DC optical tomography.

    PubMed

    Zhou, Jun; Bai, Jing; He, Ping

    2003-01-27

    In this paper, a spatial location weighted gradient-based optimization scheme for reducing the computation burden and increasing the reconstruction precision is stated. The method applies to DC diffusionbased optical tomography, where otherwise the reconstruction suffers slow convergence. The inverse approach employs a weighted steepest descent method combined with a conjugate gradient method. A reverse differentiation method is used to efficiently derive the gradient. The reconstruction results confirm that the spatial location weighted optimization method offers a more efficient approach to the DC optical imaging problem than unweighted method does.

  16. Dissociation curves of diatomic molecules: A DC-DFT study

    SciTech Connect

    Sim, Eunji; Kim, Min-Cheol; Burke, Kieron

    2015-12-31

    We investigate dissociation of diatomic molecules using standard density functional theory (DFT) and density-corrected density functional theory (DC-DFT) compared with CCSD(T) results as reference. The results show the difference between the HOMO values of dissociated atomic species often can be used as an indicator whether DFT would predict the correct dissociation limit. DFT predicts incorrect dissociation limits and charge distribution in molecules or molecular ions when the fragments have large HOMO differences, while DC-DFT and CCSD(T) do not. The criteria for large HOMO difference is about 2 ∼ 4 eV.

  17. Controller for computer control of brushless dc motors. [automobile engines

    NASA Technical Reports Server (NTRS)

    Hieda, L. S. (Inventor)

    1981-01-01

    A motor speed and torque controller for brushless d.c. motors provides an unusually smooth torque control arrangement. The controller provides a means for controlling a current waveform in each winding of a brushless dc motor by synchronization of an excitation pulse train from a programmable oscillator. Sensing of torque for synchronization is provided by a light beam chopper mounted on the motor rotor shaft. Speed and duty cycle are independently controlled by controlling the frequency and pulse width output of the programmable oscillator. A means is also provided so that current transitions from one motor winding to another is effected without abrupt changes in output torque.

  18. Graphite electrode DC arc furnace. Innovative technology summary report

    SciTech Connect

    1999-05-01

    The Graphite Electrode DC Arc Furnace (DC Arc) is a high-temperature thermal process, which has been adapted from a commercial technology, for the treatment of mixed waste. A DC Arc Furnace heats waste to a temperature such that the waste is converted into a molten form that cools into a stable glassy and/or crystalline waste form. Hazardous organics are destroyed through combustion or pyrolysis during the process and the majority of the hazardous metals and radioactive components are incorporated in the molten phase. The DC Arc Furnace chamber temperature is approximately 593--704 C and melt temperatures are as high as 1,500 C. The DC Arc system has an air pollution control system (APCS) to remove particulate and volatiles from the offgas. The advantage of the DC Arc is that it is a single, high-temperature thermal process that minimizes the need for multiple treatment systems and for extensive sorting/segregating of large volumes of waste. The DC Arc has the potential to treat a wide range of wastes, minimize the need for sorting, reduce the final waste volumes, produce a leach resistant waste form, and destroy organic contaminants. Although the DC arc plasma furnace exhibits great promise for treating the types of mixed waste that are commonly present at many DOE sites, several data and technology deficiencies were identified by the Mixed Waste Focus Area (MWFA) regarding this thermal waste processing technique. The technology deficiencies that have been addressed by the current studies include: establishing the partitioning behavior of radionuclides, surrogates, and hazardous metals among the product streams (metal, slag, and offgas) as a function of operating parameters, including melt temperature, plenum atmosphere, organic loading, chloride concentration, and particle size; demonstrating the efficacy of waste product removal systems for slag and metal phases; determining component durability through test runs of extended duration, evaluating the effect of

  19. High torque DC motor fabrication and test program

    NASA Technical Reports Server (NTRS)

    Makus, P.

    1976-01-01

    The testing of a standard iron and standard alnico permanent magnet two-phase, brushless dc spin motor for potential application to the space telescope has been concluded. The purpose of this study was to determine spin motor power losses, magnetic drag, efficiency and torque speed characteristics of a high torque dc motor. The motor was designed and built to fit an existing reaction wheel as a test vehicle and to use existing brass-board commutation and torque command electronics. The results of the tests are included in this report.

  20. Mythbusters: The Case for Retirement Income in DC Plans.

    PubMed

    Austin, Ron; Shepherd, Steve

    2016-01-01

    Myths persist about retirement income solutions in defined contribution (DC) plans. The authors put six common myths to the test: (1) that few plans offer a retirement income option, (2) that retirement is solely a product decision, (3) that retirement income options lack fiduciary clarity, (4) that it's difficult to implement a retirement income option, (5) that retirement income options can be viewed similarly to an asset class and (6) that retirement solutions are too difficult to communicate to participants. They explain why some chatter on the topic of retirement income solutions in DC plans is unfounded.

  1. Liquid meniscus oscillation and drop ejection by ac voltage, pulsed dc voltage, and superimposing dc to ac voltages

    NASA Astrophysics Data System (ADS)

    Tran, Si Bui Quang; Byun, Doyoung; Nguyen, Vu Dat; Kang, Tae Sam

    2009-08-01

    The electrohydrodynamic (EHD) spraying technique has been utilized in applications such as inkjet printing and mass spectrometry technologies. In this paper, the role of electrical potential signals in jetting and on the oscillation of the meniscus is evaluated. The jetting and the meniscus oscillation behavior are experimentally investigated under ac voltage, ac voltage superimposed on dc voltage, and pulsed dc voltage. Based on this in-depth study of the meniscus behavior under various signals, the optimal signal is implemented to an EHD inkjet head for drop-on-demand operation. For applied ac voltage and ac voltage superimposed on dc voltage, the jetting phenomenon is a dynamic process due to sequential opposite sign signals. The jetting occurs at the end of the oscillation cycle, where the meniscus oscillates upward and arrives at its highest position.

  2. High voltage dc-dc converter with dynamic voltage regulation and decoupling during load-generated arcs

    DOEpatents

    Shimer, Daniel W.; Lange, Arnold C.

    1995-01-01

    A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules.

  3. High voltage dc--dc converter with dynamic voltage regulation and decoupling during load-generated arcs

    DOEpatents

    Shimer, D.W.; Lange, A.C.

    1995-05-23

    A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules. 5 Figs.

  4. Active dc filter for HVDC system--A test installation in the Konti-Skan DC link at Lindome converter station

    SciTech Connect

    Zhang, Wenyan; Asplund, G. . HVDC Division); Aberg, A. . Dept. of Man-Machine Communication); Jonsson, U. ); Loeoef, O. . Region Vaestsverige)

    1993-07-01

    The purpose of introducing active dc filters is to meet the more and more stringent requirement from power utilities on limiting telephone interference caused by harmonic currents from HVdc transmission lines, without unnecessarily increasing the cost of HVdc stations. An active dc filter installed in the Konti-Skan HVdc link is described. The active dc filter is connected at the bottom of an existing passive dc filter at the Lindome station. The active dc filter includes optic harmonic current measuring unit, control system, protection and supervision system, PWM power amplifier, high-frequency transformer, surge arrester, and coupling apparatuses. The active dc filter has small physical size and occupies small ground area. The performance of the active dc filter for eliminating the disturbing harmonics is excellent. To achieve comparable results by passive filters would require something like ten times more high voltage equipment.

  5. Regulated dc-to-dc converter for voltage step-up or step-down with input-output isolation

    NASA Technical Reports Server (NTRS)

    Feng, S. Y.; Wilson, T. G. (Inventor)

    1973-01-01

    A closed loop regulated dc-to-dc converter employing an unregulated two winding inductive energy storage converter is provided by using a magnetically coupled multivibrator acting as duty cycle generator to drive the converter. The multivibrator is comprised of two transistor switches and a saturable transformer. The output of the converter is compared with a reference in a comparator which transmits a binary zero until the output exceeds the reference. When the output exceeds the reference, the binary output of the comparator drives transistor switches to turn the multivibrator off. The multivibrator is unbalanced so that a predetermined transistor will always turn on first when the binary feedback signal becomes zero.

  6. ASDTIC control and standardized interface circuits applied to buck, parallel and buck-boost dc to dc power converters

    NASA Technical Reports Server (NTRS)

    Schoenfeld, A. D.; Yu, Y.

    1973-01-01

    Versatile standardized pulse modulation nondissipatively regulated control signal processing circuits were applied to three most commonly used dc to dc power converter configurations: (1) the series switching buck-regulator, (2) the pulse modulated parallel inverter, and (3) the buck-boost converter. The unique control concept and the commonality of control functions for all switching regulators have resulted in improved static and dynamic performance and control circuit standardization. New power-circuit technology was also applied to enhance reliability and to achieve optimum weight and efficiency.

  7. Very-high-frequency dc-to-dc conversion and regulation in the low-megahertz range.

    NASA Technical Reports Server (NTRS)

    Feng, S. Y. M.; Wilson, T. G.; Sander, W. A., III

    1971-01-01

    Anticipated new mission requirements have motivated research on very-high-frequency (VHF) regulated dc-to-dc converters to operate at conversion frequencies in the low-megahertz range. State-of-the-art electronic components for VHF operation are discussed. Two different converter configurations, one using proportional control and having a conversion frequency of 0.1 MHz and the other using bistable control and having a conversion frequency of 3.8 MHz, are presented to indicate converter performance in this VHF region. Converter losses, which are of prime importance at these frequencies, are discussed and possible means of reducing these losses are suggested.

  8. Plasmacytoid DC from Aged Mice Down-Regulate CD8 T Cell Responses by Inhibiting cDC Maturation after Encephalitozoon cuniculi Infection

    PubMed Central

    Gigley, Jason P.; Khan, Imtiaz A.

    2011-01-01

    Age associated impairment of immune function results in inefficient vaccination, tumor surveillance and increased severity of infections. Several alterations in adaptive immunity have been observed and recent studies report age related declines in innate immune responses to opportunistic pathogens including Encephalitozoon cuniculi. We previously demonstrated that conventional dendritic cells (cDC) from 9-month-old animals exhibit sub-optimal response to E. cuniculi infection, suggesting that age associated immune senescence begins earlier than expected. We focused this study on how age affects plasmacytoid DC (pDC) function. More specifically how aged pDC affect cDC function as we observed that the latter are the predominant activators of CD8 T cells during this infection. Our present study demonstrates that pDC from middle-aged mice (12 months) suppress young (8 week old) cDC driven CD8 T cell priming against E. cuniculi infection. The suppressive effect of pDC from older mice decreased maturation of young cDC via cell contact. Aged mouse pDC exhibited higher expression of PD-L1 and blockade of their interaction with cDC via this molecule restored cDC maturation and T cell priming. Furthermore, the PD-L1 dependent suppression of cDC T cell priming was restricted to effector function of antigen-specific CD8 T cells not their expansion. To the best of our knowledge, the data presented here is the first report highlighting a cell contact dependent, PD-L1 regulated, age associated defect in a DC subpopulation that results in a sub-optimal immune response against E. cuniculi infection. These results have broad implications for design of immunotherapeutic approaches to enhance immunity for aging populations. PMID:21695169

  9. Plasmacytoid DC from aged mice down-regulate CD8 T cell responses by inhibiting cDC maturation after Encephalitozoon cuniculi infection.

    PubMed

    Gigley, Jason P; Khan, Imtiaz A

    2011-01-01

    Age associated impairment of immune function results in inefficient vaccination, tumor surveillance and increased severity of infections. Several alterations in adaptive immunity have been observed and recent studies report age related declines in innate immune responses to opportunistic pathogens including Encephalitozoon cuniculi. We previously demonstrated that conventional dendritic cells (cDC) from 9-month-old animals exhibit sub-optimal response to E. cuniculi infection, suggesting that age associated immune senescence begins earlier than expected. We focused this study on how age affects plasmacytoid DC (pDC) function. More specifically how aged pDC affect cDC function as we observed that the latter are the predominant activators of CD8 T cells during this infection. Our present study demonstrates that pDC from middle-aged mice (12 months) suppress young (8 week old) cDC driven CD8 T cell priming against E. cuniculi infection. The suppressive effect of pDC from older mice decreased maturation of young cDC via cell contact. Aged mouse pDC exhibited higher expression of PD-L1 and blockade of their interaction with cDC via this molecule restored cDC maturation and T cell priming. Furthermore, the PD-L1 dependent suppression of cDC T cell priming was restricted to effector function of antigen-specific CD8 T cells not their expansion. To the best of our knowledge, the data presented here is the first report highlighting a cell contact dependent, PD-L1 regulated, age associated defect in a DC subpopulation that results in a sub-optimal immune response against E. cuniculi infection. These results have broad implications for design of immunotherapeutic approaches to enhance immunity for aging populations.

  10. Plant Generator driven by a small Delco 32 volt DC ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Plant Generator driven by a small Delco 32 volt DC steam engine with a maximum output of 17.6 kilowatts - East Broad Top Railroad & Coal Company, Machine Shop, State Route 994, West of U.S. Route 522, Rockhill Furnace, Huntingdon County, PA

  11. Parks, Trees, and Environmental Justice: Field Notes from Washington, DC

    ERIC Educational Resources Information Center

    Buckley, Geoffrey L.; Whitmer, Ali; Grove, J. Morgan

    2013-01-01

    Students enrolled in a graduate seminar benefited in multiple ways from an intensive 3-day field trip to Washington, DC. Constructed around the theme of environmental justice, the trip gave students a chance to learn about street tree distribution, park quality, and racial segregation "up close." Working with personnel from the United…

  12. DC drive system for cine/pulse cameras

    NASA Technical Reports Server (NTRS)

    Gerlach, R. H.; Sharpsteen, J. T.; Solheim, C. D.; Stoap, L. J.

    1977-01-01

    Camera-drive functions are separated mechanically into two groups which are driven by two separate dc brushless motors. First motor, a 90 deg stepper, drives rotating shutter; second electronically commutated motor drives claw and film transport. Shutter is made of one piece but has two openings for slow and fast exposures.

  13. [A new alkaloid of Menispermum dauricum DC--dauriciline].

    PubMed

    Pang, X P; Chen, Y W; Li, X J; Long, J G

    1991-01-01

    A new phenolic dauricine-type alkaloid, named "dauriciline", was isolated from the rhizome of Menispermum dauricum DC. It is a pale yellow powder. Based on spectrometric analysis (UV.FAB-MS and 1HNMR) and chemical reaction the structure of the new alkaloid was elucidated as RR,7,7'-demethyldauricine (VI).

  14. Advanced dc motor controller for battery-powered electric vehicles

    NASA Technical Reports Server (NTRS)

    Belsterling, C. A.

    1981-01-01

    A motor generation set is connected to run from the dc source and generate a voltage in the traction motor armature circuit that normally opposes the source voltage. The functional feasibility of the concept is demonstrated with tests on a Proof of Principle System. An analog computer simulation is developed, validated with the results of the tests, applied to predict the performance of a full scale Functional Model dc Controller. The results indicate high efficiencies over wide operating ranges and exceptional recovery of regenerated energy. The new machine integrates both motor and generator on a single two bearing shaft. The control strategy produces a controlled bidirectional plus or minus 48 volts dc output from the generator permitting full control of a 96 volt dc traction motor from a 48 volt battery, was designed to control a 20 hp traction motor. The controller weighs 63.5 kg (140 lb.) and has a peak efficiency of 90% in random driving modes and 96% during the SAE J 227a/D driving cycle.

  15. Controllable Bidirectional dc Power Sources For Large Loads

    NASA Technical Reports Server (NTRS)

    Tripp, John S.; Daniels, Taumi S.

    1995-01-01

    System redesigned for greater efficiency, durability, and controllability. Modern electronically controlled dc power sources proposed to supply currents to six electromagnets used to position aerodynamic test model in wind tunnel. Six-phase bridge rectifier supplies load with large current at voltage of commanded magnitude and polarity. Current-feedback circuit includes current-limiting feature giving some protection against overload.

  16. A Testing System for Diagnosing Misconceptions in DC Electric Circuits.

    ERIC Educational Resources Information Center

    Chang, Kuo-En; Liu, Sei-Hua; Chen, Sei-Wang

    1998-01-01

    Outlines a test-based diagnosis system for misconceptions in DC electric circuits and its three parts: problem library, problem selector and diagnoser. Discusses misconception discrimination and diagnosis theories, and reports the system supports satisfactory diagnosis. Includes an analysis of nine student misconceptions about electrical circuits…

  17. Summary of electric vehicle dc motor-controller tests

    NASA Technical Reports Server (NTRS)

    Mcbrien, E. F.; Tryon, H. B.

    1982-01-01

    The differences in the performance of dc motors are evaluated when operating with chopper type controllers, and when operating on direct current. The interactions between the motor and the controller which cause these differences are investigated. Motor-controlled tests provided some of the data the quantified motor efficiency variations for both ripple free and chopper modes of operation.

  18. Washington, D.C.: A Very Great Place to Visit.

    ERIC Educational Resources Information Center

    Camping Magazine, 1986

    1986-01-01

    Describes places of interest in Washington, D.C. for attendees of the Second International Camping Congress on March 2-6, 1987. Includes information about the Capitol, Air and Space Museum, National Museum of Natural History, National Museum of American History, Washington Monument, Lincoln Memorial, and White House. Contains photographs of four…

  19. Wireless Content Repurposing Architecture for DC Command and Control

    DTIC Science & Technology

    2003-09-01

    COMMAND AND CONTROL by Robert J. Suh September 2003 Thesis Advisor: Gurminder Singh Second Reader: Perry McDowell...data sources , gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this...3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE: Wireless Content Repurposing Architecture for DC Command and Control

  20. A citywide breeding bird survey for Washington, DC

    USGS Publications Warehouse

    Hadidian, J.; Sauer, J.R.; Swarth, C.; Handly, P.; Droege, S.; Williams, C.; Huff, J.; Didden, G.

    1997-01-01

    `DC Birdscape' was initiated in 1993 to systematically count the birds occurring throughout Washington D.C. during the breeding season. It involved a coordinated planning effort and partnership between the Audubon Naturalist Society, the National Park Service, and the National Biological Survey, and engaged the participation of more than 100 volunteers. A method for rapidly assessing the status of bird populations over a large area was developed and incorporated into a Geographic Information System to allow a multidimensional analysis of species presence and abundance across a variety of urban land use areas. A total of 91 species were observed, with an estimated total number of 115, making Washington D.C. almost as `bird rich' as nearby suburban counties. Data from the study clearly indicate that avian species are not randomly distributed throughout the Washington D.C. metropolitan area, and show affinity, at least in part, to some of the most broadly recognized land use patterns that are commonly used to zone and classify urban areas under development schemes. This study represents a prototype that will allow efficient and economical monitoring of urban bird populations.

  1. Turbulence Measurements by the DC-8 Meteorological Measurement System

    NASA Technical Reports Server (NTRS)

    Chan, K. R.; Dean-Day, J.; Bowen, S. W.; Bui, T. P.; Chan, K. Roland (Technical Monitor)

    1997-01-01

    The instrumentation of a new MMS on the DC-8 aircraft is briefly described. Methods to compute and evaluate the turbulent dissipation rate epsilon, based on theory and MMS data, are discussed. Examples of turbulence measurements during encounters of a wake vortex, wave clouds, persistent contrails, mountain are gravity waves are illustrated.

  2. A brushless dc spin motor for momentum exchange altitude control

    NASA Technical Reports Server (NTRS)

    Stern, D.; Rosenlieb, J. W.

    1972-01-01

    Brushless dc spin motor is designed to use Hall effect probes as means of revolving rotor position and controlling motor winding currents. This results in 3 to 1 reduction in watt-hours required for wheel acceleration, a 2 to 1 reduction in power to run wheel, and a 10 to 1 reduction in the electronics size and weight.

  3. HTS DC Transmission Line for Megalopolis Grid Development

    NASA Astrophysics Data System (ADS)

    Kopylov, S.; Sytnikov, V.; Bemert, S.; Ivanov, Yu; Krivetskiy, I.; Romashov, M.; Shakaryan, Yu; Keilin, V.; Shikov, A.; Patrikeev, V.; Lobyntsev, V.; Shcherbakov, V.

    2014-05-01

    Using of HTS AC and DC cables in electric power grids allows increasing of the transferred power, losses diminishing, decreasing of exclusion zone areas, the enhancement of the environmental conditions and fire/explosion safety of electric power systems. However, the use of DC superconducting cable lines together with converters brings additional advantages as reduction of losses in cables and suitable lowering of refrigerating plant capacity, as well as the realization of the function of short-circuit currents limitation by means of the appropriate setting of converter equipment. Russian Federal Grid Company and its R&D Center started the construction of the DC HTS power transmission line which includes the cable itself, cryogenic equipment, AC/DC converters, terminals and cable coupling boxes. This line will connect two substations in Saint-Petersburg - 330 kV "Centralnaya" and 220 kV "RP-9". The length of this HTS transmission line will be about 2500 meters. Nowadays are developed all the elements of the line and technologies of the cable manufacturing. Two HTS cable samples, each 30 m length, have been made. This paper describes the results of cables tests.

  4. A High Efficiency DC Bus Regulator / RPC for Spacecraft Applications

    NASA Astrophysics Data System (ADS)

    Birchenough, Arthur G.

    2004-02-01

    DC bus voltage regulation may be required in future high powered spacecraft due to the length of the busses or because they are not generated at precise voltage levels. In these cases the regulation range is often only a few percent increase or decrease, but conventional DC voltage regulators switch all the power passing through them, and this level of power switched determines the size and losses in the regulator. A recently developed concept uses a low power DC-DC converter in series with the bus to raise or lower the bus voltage over a small range. This partial power processing technique combines the small size and power losses of the low power converter with the ability to regulate, (over a small range) a high power bus. The Series Connected Buck Boost Regulator (SCBBR) described herein provides bus regulation with an efficiency of 98%. The circuit also provides bus switching and overcurrent limiting functions of a Remote Power Controller (RPC). This paper describes the circuit design and performance of a breadboard SCBBR configured as a bus voltage regulator providing +/- 40% voltage regulation range, bus switching, and overload limiting.

  5. Transcriptional IL-15-Directed in vivo DC Targeting DNA Vaccine

    PubMed Central

    Tian, S; Liu, Z; Donahue, C; Noh, HS; Falo, LD; You, Z

    2009-01-01

    DC engineered in vitro by DNA encoding OVAhsp70 and IL-15 up-regulated their expressions of CD80, CD86, CCR7 and IL-15Rα and promoted their productions of IL-6, IL-12 and TNF-α. Transcriptional IL-15-directed in vivo DC targeting DNA vaccine encoding OVAhsp70 elicited long-lasting Th1 and CTL responses and anti-B16OVA activity. CD8 T cell-mediated primary tumor protection was abrogated by DC or CD4 T cell depletion during the induction phase of immune responses. However, CD4 T cell depletion during immunization did not impair CD8 T cell-dependent long-lasting tumor protection. Furthermore, in vivo DC-derived IL-15 exerted the enhancements of cellular and humoral immune responses and antitumor immunity elicited by OVAhsp70 DNA vaccine. Importantly, the potency of this novel DNA vaccine strategy was proven using a self/tumor Ag (TRP2) in a clinically relevant B16 melanoma model. These findings have implications for developing next generation DNA vaccines against cancers and infectious diseases in both healthy and CD4 deficient individuals. PMID:19727134

  6. Anomalous dc resistivity and double layers in the auroral ionosphere

    SciTech Connect

    Kindel, J.M.; Barnes, C.; Forslund, D.W.

    1980-01-01

    There are at least four candidate instabilities which might account for anomalous dc rereresistivity in the auroral ionosphere. These are: the ion-acoustic instability, the Buneman instability, the ion-cyclotron instability and double layers. Results are reported of computer simulations of these four instabilities which suggest that double layers are most likely to be responsible for sistivity in the auroral zone.

  7. Hardware Evolution of Analog Speed Controllers for a DC Motor

    NASA Technical Reports Server (NTRS)

    Gwaltney, David A.; Ferguson, Michael I.

    2003-01-01

    This viewgraph presentation provides information on the design of analog speed controllers for DC motors on aerospace systems. The presentation includes an overview of controller evolution, evolvable controller configuration, an emphasis on proportion integral (PI) controllers, schematic diagrams, and experimental results.

  8. School Vouchers and Student Outcomes: Experimental Evidence from Washington, DC

    ERIC Educational Resources Information Center

    Wolf, Patrick J.; Kisida, Brian; Gutmann, Babette; Puma, Michael; Eissa, Nada; Rizzo, Lou

    2013-01-01

    School vouchers are the most contentious form of parental school choice. Vouchers provide government funds that parents can use to send their children to private schools of their choice. Here we examine the empirical question of whether or not a school voucher program in Washington, DC, affected achievement or the rate of high school graduation…

  9. Anisotropic Thermal Behavior of Silicone Polymer, DC 745

    SciTech Connect

    Adams, Jillian Cathleen; Torres, Joseph Angelo; Volz, Heather Michelle; Gallegos, Jennifer Marie; Yang, Dali

    2016-09-02

    In material applications, it is important to understand how polymeric materials behave in the various environments they may encounter. One factor governing polymer behavior is processing history. Differences in fabrication will result in parts with varied or even unintended properties. In this work, the thermal expansion behavior of silicone DC 745 is studied. Thermomechanical analysis (TMA) is used to determine changes in sample dimension resulting from changes in temperature. This technique can measure thermal events such as the linear coefficient of thermal expansion (CTE), melting, glass transitions, cure shrinkage, and internal relaxations. Using a thermomechanical analyzer (Q400 TMA), it is determined that DC 745 expands anisotropically when heated. This means that the material has a different CTE depending upon which direction is being measured. In this study, TMA experiments were designed in order to confirm anisotropic thermal behavior in multiple DC 745 samples of various ages and lots. TMA parameters such as temperature ramp rate, preload force, and temperature range were optimized in order to ensure the most accurate and useful data. A better understanding of the thermal expansion of DC 745 will allow for more accurate modeling of systems using this material.

  10. 77 FR 47907 - District of Columbia Disaster #DC-00005

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-10

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION District of Columbia Disaster DC-00005 AGENCY: U.S. Small Business Administration. ACTION: Notice... Disaster Assistance, U.S. Small Business Administration, 409 3rd Street SW., Suite 6050, Washington,...

  11. 76 FR 62131 - District of Columbia Disaster #DC-00003

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-06

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION District of Columbia Disaster DC-00003 AGENCY: U.S. Small Business Administration. ACTION: Notice... Disaster Assistance, U.S. Small Business Administration, 409 3rd Street, SW., Suite 6050, Washington,...

  12. 36 CFR 910.13 - Urban design of Washington, DC.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 3 2013-07-01 2012-07-01 true Urban design of Washington, DC. 910.13 Section 910.13 Parks, Forests, and Public Property PENNSYLVANIA AVENUE DEVELOPMENT CORPORATION... PENNSYLVANIA AVENUE DEVELOPMENT AREA Urban Planning and Design Concerns § 910.13 Urban design of Washington,...

  13. Electrostatic coalescence system with independent AC and DC hydrophilic electrodes

    DOEpatents

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

    1981-01-01

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

  14. 36 CFR 910.13 - Urban design of Washington, DC.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 3 2012-07-01 2012-07-01 false Urban design of Washington, DC. 910.13 Section 910.13 Parks, Forests, and Public Property PENNSYLVANIA AVENUE DEVELOPMENT... PENNSYLVANIA AVENUE DEVELOPMENT AREA Urban Planning and Design Concerns § 910.13 Urban design of Washington,...

  15. 36 CFR 910.13 - Urban design of Washington, DC.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 3 2014-07-01 2014-07-01 false Urban design of Washington, DC. 910.13 Section 910.13 Parks, Forests, and Public Property PENNSYLVANIA AVENUE DEVELOPMENT... PENNSYLVANIA AVENUE DEVELOPMENT AREA Urban Planning and Design Concerns § 910.13 Urban design of Washington,...

  16. 36 CFR 910.13 - Urban design of Washington, DC.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 3 2011-07-01 2011-07-01 false Urban design of Washington, DC. 910.13 Section 910.13 Parks, Forests, and Public Property PENNSYLVANIA AVENUE DEVELOPMENT... PENNSYLVANIA AVENUE DEVELOPMENT AREA Urban Planning and Design Concerns § 910.13 Urban design of Washington,...

  17. 77 FR 74907 - District of Columbia Disaster #DC-00006

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-18

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION District of Columbia Disaster DC-00006 AGENCY: U.S. Small Business Administration. ACTION: Notice... Disaster Assistance, U.S. Small Business Administration, 409 3rd Street SW., Suite 6050, Washington,...

  18. 76 FR 72021 - District of Columbia Disaster #DC-00004

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-21

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION District of Columbia Disaster DC-00004 AGENCY: U.S. Small Business Administration. ACTION: Notice... Disaster Assistance, U.S. Small Business Administration, 409 3rd Street SW., Suite 6050, Washington,...

  19. 36 CFR 910.13 - Urban design of Washington, DC.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Urban design of Washington, DC. 910.13 Section 910.13 Parks, Forests, and Public Property PENNSYLVANIA AVENUE DEVELOPMENT... PENNSYLVANIA AVENUE DEVELOPMENT AREA Urban Planning and Design Concerns § 910.13 Urban design of Washington,...

  20. Lucid Provides Energy Reduction Software to DC Government

    EPA Pesticide Factsheets

    Earlier this year, Lucid, a 2014 U.S. EPA SBIR award recipient, announced that the D.C. government was using Lucid's BuildingOS® software in order to reach an an energy reduction target of 20 percent in 20 months

  1. Brushless dc motors. [applications in non-space technology

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Brushless dc motors were intensively developed and tested over several years before qualification as the prime movers for Apollo Spacecraft life support blowers, and for circulating oxygen in the lunar portable life support system. Knowledge gained through prototype development and critical testing has significantly influenced the technology employed, broadened markets and applications, and reduced the cost of present day motors.

  2. Normalizing and converting image DC data using scatter plot matching

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Remote sensing image data from sources such as Landsat or airborne multispectral digital cameras are typically in the form of digital count (DC) values. To compare images acquired by the same sensor system on different dates, or images acquired by different sensor systems, it is necessary to correct...

  3. Recovery Act: Integrated DC-DC Conversion for Energy-Efficient Multicore Processors

    SciTech Connect

    Shepard, Kenneth L

    2013-03-31

    In this project, we have developed the use of thin-film magnetic materials to improve in energy efficiency of digital computing applications by enabling integrated dc-dc power conversion and management with on-chip power inductors. Integrated voltage regulators also enables fine-grained power management, by providing dynamic scaling of the supply voltage in concert with the clock frequency of synchronous logic to throttle power consumption at periods of low computational demand. The voltage converter generates lower output voltages during periods of low computational performance requirements and higher output voltages during periods of high computational performance requirements. Implementation of integrated power conversion requires high-capacity energy storage devices, which are generally not available in traditional semiconductor processes. We achieve this with integration of thin-film magnetic materials into a conventional complementary metal-oxide-semiconductor (CMOS) process for high-quality on-chip power inductors. This project includes a body of work conducted to develop integrated switch-mode voltage regulators with thin-film magnetic power inductors. Soft-magnetic materials and inductor topologies are selected and optimized, with intent to maximize efficiency and current density of the integrated regulators. A custom integrated circuit (IC) is designed and fabricated in 45-nm CMOS silicon-on-insulator (SOI) to provide the control system and power-train necessary to drive the power inductors, in addition to providing a digital load for the converter. A silicon interposer is designed and fabricated in collaboration with IBM Research to integrate custom power inductors by chip stacking with the 45-nm CMOS integrated circuit, enabling power conversion with current density greater than 10A/mm2. The concepts and designs developed from this work enable significant improvements in performance-per-watt of future microprocessors in servers, desktops, and mobile

  4. Baseline and Lifetime Assessments for DC745U Elastomeric Components

    SciTech Connect

    Maxwell, R S; Chinn, S C; Herberg, J; Harvey, C; Alviso, C; Vance, A; Cohenour, R; Wilson, M; Solyom, D

    2004-12-20

    The silicone elastomer Dow Corning DC 745U is used in two major components in the W80. We have investigated a number of issues concerning this material. Our studies have accomplished a baseline study of the chemical composition of DC745 and LLNL now has a good understanding of the chemical composition of this material. DC745 crystallizes within the system STS. Two potential means identified to mitigate the risk associated with this phenomenon are to (1) change material formulation and (2) predose the parts to {approx} 25 MRad {gamma}-radiation. A candidate material identified by Gordon Spellman has been studied for composition and the lack of crystallization within the STS has been verified. A sensitivity study of the effects of relevant aging mechanisms also has been performed. The extent of aging due to radiation exposure or elevated temperatures is minimal over the expected course of the LEP. In addition, since the DC745 parts are expected to be replaced at rebuild, the aging clock is essentially being reset. No significant aging issues seem likely to develop for these parts. DC745 parts are also subject to permanent deformation in service. Our studies have shown that the deformation is likely due to incomplete mixing of the raw gum stock and the curing agent at production. This results in areas of low crosslink density that are subject to a higher degree of compression set in service. We have identified two production diagnostic tools based on Nuclear Magnetic Resonance spectroscopy to prescreen the parts at production at KCP. These studies are concluded with specific recommendation for changes to core surveillance for this part based on the chemical knowledge we have gained from this study.

  5. The Deep Convective Clouds and Chemistry (DC3) Field Experiment

    NASA Astrophysics Data System (ADS)

    Barth, M. C.; Brune, W. H.; Cantrell, C. A.; Rutledge, S. A.; Crawford, J. H.; Huntrieser, H.; Homeyer, C. R.; Nault, B.; Cohen, R. C.; Pan, L.; Ziemba, L. D.

    2014-12-01

    The Deep Convective Clouds and Chemistry (DC3) field experiment took place in the central U.S. in May and June 2012 and had the objectives of characterizing the effect of thunderstorms on the chemical composition of the lower atmosphere and determining the chemical aging of upper troposphere (UT) convective outflow plumes. DC3 employed ground-based radars, lightning mapping arrays, and weather balloon soundings in conjunction with aircraft measurements sampling the composition of the inflow and outflow of a variety of thunderstorms in northeast Colorado, West Texas to central Oklahoma, and northern Alabama. A unique aspect of the DC3 strategy was to locate and sample the convective outflow a day after active convection in order to measure the chemical transformations within the UT convective plume. The DC3 data are being analyzed to investigate transport and dynamics of the storms, scavenging of soluble trace gases and aerosols, production of nitrogen oxides by lightning, relationships between lightning flash rates and storm parameters, and chemistry in the UT that is affected by the convection. In this presentation, we give an overview of the DC3 field campaign and highlight results from the campaign that are relevant to the upper troposphere and lower stratosphere region. These highlights include stratosphere-troposphere exchange in connection with thunderstorms, the 0-12 hour chemical aging and new particle formation in the UT outflow of a dissipating mesoscale convective system observed on June 21, 2012, and UT chemical aging in convective outflow as sampled the day after convection occurred and modeled in the Weather Research and Forecasting coupled with Chemistry model.

  6. The two cytochrome c species, DC3 and DC4, are not required for caspase activation and apoptosis in Drosophila cells.

    PubMed

    Dorstyn, Loretta; Mills, Kathryn; Lazebnik, Yuri; Kumar, Sharad

    2004-11-08

    In Drosophila, activation of the apical caspase DRONC requires the apoptotic protease-activating factor homologue, DARK. However, unlike caspase activation in mammals, DRONC activation is not accompanied by the release of cytochrome c from mitochondria. Drosophila encodes two cytochrome c proteins, Cytc-p (DC4) the predominantly expressed species, and Cytc-d (DC3), which is implicated in caspase activation during spermatogenesis. Here, we report that silencing expression of either or both DC3 and DC4 had no effect on apoptosis or activation of DRONC and DRICE in Drosophila cells. We find that loss of function mutations in dc3 and dc4, do not affect caspase activation during Drosophila development and that ectopic expression of DC3 or DC4 in Drosophila cells does not induce caspase activation. In cell-free studies, recombinant DC3 or DC4 failed to activate caspases in Drosophila cell lysates, but remarkably induced caspase activation in extracts from human cells. Overall, our results argue that DARK-mediated DRONC activation occurs independently of cytochrome c.

  7. A three-phase soft-switched high-power-density dc/dc converter for high power applications

    SciTech Connect

    DeDoncker, R.W.A.A. ); Divan, D.M.; Kheraluwala, M.H. )

    1991-01-01

    In this paper three dc/dc converter topologies suitable for high-power-density high-power applications are presented. All three circuits operate in a soft-switched manner, making possible a reduction in device switching losses and an increase in switching frequency. The three-phase dual-bridge converter proposed is seen to have the most favorable characteristics. This converter consists of two three-phase inverter stages operating in a high-frequency six-step mode. In contrast to existing single-phase ac-link dc/dc converters, lower turn-off peak currents in the power devices and lower rms current ratings for both the input and output filter capacitors are obtained. This is in addition to smaller filter element values due to the higher-frequency content of the input and output waveforms. Furthermore, the use of a three phase symmetrical transformer instead of single-phase transformers and a better utilization of the available apparent power of the transformer (as a consequence of the controlled output inverter) significantly increase the power density attainable.

  8. Dab2, a negative regulator of DC immunogenicity, is an attractive molecular target for DC-based immunotherapy.

    PubMed

    Ahmed, Md Selim; Byeon, Se Eun; Jeong, Yideul; Miah, Mohammad Alam; Salahuddin, Md; Lee, Yoon; Park, Sung-Soo; Bae, Yong-Soo

    2015-01-01

    Dab2 is an adapter protein involved in receptor-mediated signaling, endocytosis, cell adhesion, hematopoietic cell differentiation, and angiogenesis. It plays a pivotal role in controlling cellular homeostasis. In the immune system, the Dab2 is a Foxp3 target gene and is required for regulatory T (Treg) cell function. Dab2 expression and its biological function in dendritic cells (DCs) have not been described. In this study, we found that Dab2 was significantly induced during the development of mouse bone marrow (BM)-derived DCs (BMDCs) and human monocyte-derived DCs (MoDCs). Even in a steady state, Dab2 was expressed in mouse splenic DCs (spDCs). STAT5 activation, Foxp3 expression, and hnRNPE1 activation mediated by PI3K/Akt signaling were required for Dab2 expression during GM-CSF-derived BMDC development regardless of TGF-β signaling. Dab2-silencing was accompanied by enhanced IL-12 and IL-6 expression, and an improved capacity of DC for antigen uptake, migration and T cell stimulation, which generated strong CTL in vaccinated mice. Vaccination with Dab2-silenced DCs inhibited tumor growth more effectively than did vaccination with wild type DCs. Dab2-overexpression abrogated the efficacy of the DC vaccine in DC-based tumor immunotherapy. These data strongly suggest that Dab2 might be an intrinsic negative regulator of the immunogenicity of DCs, thus might be an attractive molecular target to improve DC vaccine efficacy.

  9. 21 CFR 82.1205 - D&C Green No. 5.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Drugs and Cosmetics § 82.1205 D&C Green No. 5. The color additive D&C Green No. 5 shall conform in identity and specifications to the requirements of §...

  10. 21 CFR 82.1602 - D&C Violet No. 2.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Drugs and Cosmetics § 82.1602 D&C Violet No. 2. The color additive D&C Violet No. 2 shall conform in identity and specifications to the requirements of §...

  11. 21 CFR 82.1333 - D&C Red No. 33.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Drugs and Cosmetics § 82.1333 D&C Red No. 33. (a) The color additive D&C Red. No. 33 shall conform in identity and specifications to the requirements of §...

  12. 21 CFR 82.1602 - D&C Violet No. 2.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Drugs and Cosmetics § 82.1602 D&C Violet No. 2. The color additive D&C Violet No. 2 shall conform in identity and specifications to the requirements of §...

  13. 21 CFR 82.1333 - D&C Red No. 33.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Drugs and Cosmetics § 82.1333 D&C Red No. 33. (a) The color additive D&C Red. No. 33 shall conform in identity and specifications to the requirements of §...

  14. 21 CFR 82.1710 - D&C Yellow No. 10.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... CERTIFIED PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Drugs and Cosmetics § 82.1710 D&C Yellow No. 10. The color additive D&C Yellow No. 10 shall conform in identity and specifications to the...

  15. 21 CFR 82.1333 - D&C Red No. 33.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Drugs and Cosmetics § 82.1333 D&C Red No. 33. (a) The color additive D&C Red. No. 33 shall conform in identity and specifications to the requirements of §...

  16. 21 CFR 82.1710 - D&C Yellow No. 10.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... CERTIFIED PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Drugs and Cosmetics § 82.1710 D&C Yellow No. 10. The color additive D&C Yellow No. 10 shall conform in identity and specifications to the...

  17. 21 CFR 82.1205 - D&C Green No. 5.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Drugs and Cosmetics § 82.1205 D&C Green No. 5. The color additive D&C Green No. 5 shall conform in identity and specifications to the requirements of §...

  18. 21 CFR 82.1602 - D&C Violet No. 2.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Drugs and Cosmetics § 82.1602 D&C Violet No. 2. The color additive D&C Violet No. 2 shall conform in identity and specifications to the requirements of §...

  19. 21 CFR 82.1710 - D&C Yellow No. 10.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... CERTIFIED PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Drugs and Cosmetics § 82.1710 D&C Yellow No. 10. The color additive D&C Yellow No. 10 shall conform in identity and specifications to the...

  20. 21 CFR 82.1602 - D&C Violet No. 2.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Drugs and Cosmetics § 82.1602 D&C Violet No. 2. The color additive D&C Violet No. 2 shall conform in identity and specifications to the requirements of §...

  1. 21 CFR 82.1205 - D&C Green No. 5.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Drugs and Cosmetics § 82.1205 D&C Green No. 5. The color additive D&C Green No. 5 shall conform in identity and specifications to the requirements of §...

  2. 21 CFR 82.1205 - D&C Green No. 5.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Drugs and Cosmetics § 82.1205 D&C Green No. 5. The color additive D&C Green No. 5 shall conform in identity and specifications to the requirements of §...

  3. 21 CFR 82.1710 - D&C Yellow No. 10.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... CERTIFIED PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Drugs and Cosmetics § 82.1710 D&C Yellow No. 10. The color additive D&C Yellow No. 10 shall conform in identity and specifications to the...

  4. 21 CFR 82.1710 - D&C Yellow No. 10.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... CERTIFIED PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Drugs and Cosmetics § 82.1710 D&C Yellow No. 10. The color additive D&C Yellow No. 10 shall conform in identity and specifications to the...

  5. 21 CFR 82.1333 - D&C Red No. 33.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Drugs and Cosmetics § 82.1333 D&C Red No. 33. (a) The color additive D&C Red. No. 33 shall conform in identity and specifications to the requirements of §...

  6. 21 CFR 82.1333 - D&C Red No. 33.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Drugs and Cosmetics § 82.1333 D&C Red No. 33. (a) The color additive D&C Red. No. 33 shall conform in identity and specifications to the requirements of §...

  7. 21 CFR 82.1602 - D&C Violet No. 2.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... PROVISIONALLY LISTED COLORS AND SPECIFICATIONS Drugs and Cosmetics § 82.1602 D&C Violet No. 2. The color additive D&C Violet No. 2 shall conform in identity and specifications to the requirements of §...

  8. Experimental Investigation of DC-Bias Related Core Losses in a Boost Inductor (Postprint)

    DTIC Science & Technology

    2014-08-01

    dc bias-flux conditions. These dc bias conditions result in distorted hysteresis loops, increased core losses, and have been shown to be independent...core are proportional to the controllable converter load currents, this topology is ideal to study dc-related losses. Inductor core B-H hysteresis ...These dc bias conditions result in dis- torted hysteresis loops, increased core losses, and have been shown to be independent of core material. The

  9. 21 CFR 74.1104 - D&C Blue No. 4.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... ADDITIVES SUBJECT TO CERTIFICATION Drugs § 74.1104 D&C Blue No. 4. (a) Identity. (1) The color additive D&C... million. Total color, not less than 85 percent. (c) Uses and restrictions. D&C Blue No. 4 may be safely... 21 Food and Drugs 1 2014-04-01 2014-04-01 false D&C Blue No. 4. 74.1104 Section 74.1104 Food...

  10. 21 CFR 74.1104 - D&C Blue No. 4.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ADDITIVES SUBJECT TO CERTIFICATION Drugs § 74.1104 D&C Blue No. 4. (a) Identity. (1) The color additive D&C... million. Total color, not less than 85 percent. (c) Uses and restrictions. D&C Blue No. 4 may be safely... 21 Food and Drugs 1 2010-04-01 2010-04-01 false D&C Blue No. 4. 74.1104 Section 74.1104 Food...

  11. 21 CFR 74.1330 - D&C Red No. 30.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... ADDITIVES SUBJECT TO CERTIFICATION Drugs § 74.1330 D&C Red No. 30. (a) Identity. (1) The color additive D&C... thiophen-3(2H)-one (CAS Reg. No. 2379-74-0). (2) Color additive mixtures for drug use made with D&C Red No... as safe for use in color additive mixtures for coloring drugs. (b) Specifications. D&C Red No....

  12. 21 CFR 74.1339 - D&C Red No. 39.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false D&C Red No. 39. 74.1339 Section 74.1339 Food and... ADDITIVES SUBJECT TO CERTIFICATION Drugs § 74.1339 D&C Red No. 39. (a) Identity. (1) The color additive D&C Red No. 39 is o- -benzoic acid. (2) Color additive mixtures made with D&C Red No. 39 may contain...

  13. 21 CFR 74.1339 - D&C Red No. 39.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false D&C Red No. 39. 74.1339 Section 74.1339 Food and... ADDITIVES SUBJECT TO CERTIFICATION Drugs § 74.1339 D&C Red No. 39. (a) Identity. (1) The color additive D&C Red No. 39 is o- -benzoic acid. (2) Color additive mixtures made with D&C Red No. 39 may contain...

  14. 21 CFR 74.1339 - D&C Red No. 39.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false D&C Red No. 39. 74.1339 Section 74.1339 Food and... ADDITIVES SUBJECT TO CERTIFICATION Drugs § 74.1339 D&C Red No. 39. (a) Identity. (1) The color additive D&C Red No. 39 is o- -benzoic acid. (2) Color additive mixtures made with D&C Red No. 39 may contain...

  15. Evaluation of the Impact of Towing DC-9 Transport Airplanes at Boston-Logan Airport.

    DTIC Science & Technology

    1980-05-01

    47 6. BOLT-SHOULDER-DRAG BRACE. .. ..... ..... ...... 47 7. HOUSING . .. ... ..... .... ..... ......... 52 8. PISTON-AXLE...DC-9 SERIES 30 PART NO. 3920626 BOLT, SHOULDER-DRAG BRACE . . . 53 31 DC-9 SERIES 50 PART NO. 3920626 BOLT, SHOULDER-DRAG BRACE . . . 54 32 HOUSING ...55 33 DC-9 SERIES 10 PART NO. 5927071 AND PART NO. 5928678, HOUSING . . 57 33 DC-9 SERIES 30 PART NO. 5927079

  16. 21 CFR 74.2307 - D&C Red No. 7

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ADDITIVES SUBJECT TO CERTIFICATION Cosmetics § 74.2307 D&C Red No. 7 (a) Identity and specifications. The color additive D&C Red No. 7 shall conform in identity and specifications to the requirements of § 74.1307 (a)(1) and (b). (b) Uses and restrictions. The color additive D&C Red No. 7 may be safely used...

  17. 21 CFR 74.2602 - D&C Violet No. 2.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ADDITIVES SUBJECT TO CERTIFICATION Cosmetics § 74.2602 D&C Violet No. 2. (a) Identity and specifications. The color additive D&C Violet No. 2 shall conform in identity and specifications to the requirements of § 74.1602(a)(1) and (b). (b) Uses and restrictions. The color additive D&C Violet No. 2 may...

  18. 21 CFR 74.2710 - D&C Yellow No. 10.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... COLOR ADDITIVES SUBJECT TO CERTIFICATION Cosmetics § 74.2710 D&C Yellow No. 10. (a) Identity and specifications. The color additive D&C Yellow No. 10 shall conform in identity and specifications to the requirements of § 74.1710(a)(1) and (b). (b) Uses and restrictions. The color additive D&C Yellow No. 10 may...

  19. 21 CFR 74.2321 - D&C Red No. 21.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ADDITIVES SUBJECT TO CERTIFICATION Cosmetics § 74.2321 D&C Red No. 21. (a) Identity and specifications. The color additive D&C Red No. 21 shall conform in identity and specifications to the requirements of § 74.1321(a)(1) and (b). (b) Uses and restrictions. The color additive D&C Red No. 21 may be safely used...

  20. 21 CFR 74.2306 - D&C Red No. 6.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ADDITIVES SUBJECT TO CERTIFICATION Cosmetics § 74.2306 D&C Red No. 6. (a) Identity and specifications.The color additive D&C Red No. 6 shall conform in identity and specifications to the requirements of § 74.1306 (a)(1) and (b). (b) Uses and restrictions. The color additive D&C Red No. 6 may be safely used...

  1. 21 CFR 74.2322 - D&C Red No. 22.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ADDITIVES SUBJECT TO CERTIFICATION Cosmetics § 74.2322 D&C Red No. 22. (a) Identity and specifications. The color additive D&C Red No. 22 shall conform in identity and specifications to the requirements of § 74.1322(a)(1) and (b). (b) Uses and restrictions. The color additive D&C Red No. 22 may be safely used...

  2. 21 CFR 74.2306 - D&C Red No. 6.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... ADDITIVES SUBJECT TO CERTIFICATION Cosmetics § 74.2306 D&C Red No. 6. (a) Identity and specifications.The color additive D&C Red No. 6 shall conform in identity and specifications to the requirements of § 74.1306 (a)(1) and (b). (b) Uses and restrictions. The color additive D&C Red No. 6 may be safely used...

  3. 21 CFR 74.1336 - D&C Red No. 36.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... ADDITIVES SUBJECT TO CERTIFICATION Drugs § 74.1336 D&C Red No. 36. (a) Identity. (1) The color additive D&C Red No. 36 is 1- -2-naphthalenol (CAS Reg. No. 2814-77-9). The color additive is manufactured by...) Color additive mixtures for drug use made with D&C Red No. 36 may contain only those diluents that...

  4. 21 CFR 74.2321 - D&C Red No. 21.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... ADDITIVES SUBJECT TO CERTIFICATION Cosmetics § 74.2321 D&C Red No. 21. (a) Identity and specifications. The color additive D&C Red No. 21 shall conform in identity and specifications to the requirements of § 74.1321(a)(1) and (b). (b) Uses and restrictions. The color additive D&C Red No. 21 may be safely used...

  5. 21 CFR 74.2602 - D&C Violet No. 2.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... ADDITIVES SUBJECT TO CERTIFICATION Cosmetics § 74.2602 D&C Violet No. 2. (a) Identity and specifications. The color additive D&C Violet No. 2 shall conform in identity and specifications to the requirements of § 74.1602(a)(1) and (b). (b) Uses and restrictions. The color additive D&C Violet No. 2 may...

  6. 21 CFR 74.2322 - D&C Red No. 22.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... ADDITIVES SUBJECT TO CERTIFICATION Cosmetics § 74.2322 D&C Red No. 22. (a) Identity and specifications. The color additive D&C Red No. 22 shall conform in identity and specifications to the requirements of § 74.1322(a)(1) and (b). (b) Uses and restrictions. The color additive D&C Red No. 22 may be safely used...

  7. 21 CFR 74.1206 - D&C Green No. 6.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... consistent with current good manufacturing practice. (d) Labeling. The label of the color additive shall... ADDITIVES SUBJECT TO CERTIFICATION Drugs § 74.1206 D&C Green No. 6. (a) Identity. The color additive D&C... additive D&C Green No. 6 for use in coloring externally applied drugs shall conform to the...

  8. 21 CFR 74.2307 - D&C Red No. 7

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... ADDITIVES SUBJECT TO CERTIFICATION Cosmetics § 74.2307 D&C Red No. 7 (a) Identity and specifications. The color additive D&C Red No. 7 shall conform in identity and specifications to the requirements of § 74.1307 (a)(1) and (b). (b) Uses and restrictions. The color additive D&C Red No. 7 may be safely used...

  9. 21 CFR 74.1331 - D&C Red No. 31.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... amounts consistent with good manufacturing practice. (d) Labeling. The label of the color additive and any... ADDITIVES SUBJECT TO CERTIFICATION Drugs § 74.1331 D&C Red No. 31. (a) Identity. (1) The color additive D&C...) Color additive mixtures for drug use made with D&C Red No. 31 may contain only those diluents that...

  10. 21 CFR 74.1334 - D&C Red No. 34.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... ADDITIVES SUBJECT TO CERTIFICATION Drugs § 74.1334 D&C Red No. 34. (a) Identity. (1) The color additive D&C... additive mixtures for drug use made with D&C Red No. 34 may contain only those diluents that are suitable and that are listed in part 73 of this chapter as safe for use in color additive mixtures for...

  11. 21 CFR 74.2710 - D&C Yellow No. 10.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... COLOR ADDITIVES SUBJECT TO CERTIFICATION Cosmetics § 74.2710 D&C Yellow No. 10. (a) Identity and specifications. The color additive D&C Yellow No. 10 shall conform in identity and specifications to the requirements of § 74.1710(a)(1) and (b). (b) Uses and restrictions. The color additive D&C Yellow No. 10 may...

  12. 76 FR 20968 - Application To Export Electric Energy; DC Energy Texas, LLC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-14

    ... Application To Export Electric Energy; DC Energy Texas, LLC AGENCY: Office of Electricity Delivery and Energy Reliability, DOE. ACTION: Notice of application. SUMMARY: DC Energy Texas, LLC (DCE Texas) has requested.... Department of Energy, 1000 Independence Avenue, SW., Washington, DC 20585-0350. Because of delays in...

  13. 14 CFR 93.337 - Requirements for operating in the DC SFRA.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Requirements for operating in the DC SFRA... TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Washington, DC Metropolitan Area Special Flight Rules Area § 93.337 Requirements for operating in the DC SFRA. A...

  14. 76 FR 55157 - Final Public Meeting in Washington, DC for the Proposed Keystone XL Project

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-06

    ... Public Meeting in Washington, DC for the Proposed Keystone XL Project AGENCY: Department of State. ACTION: Notice of final public meeting in Washington, DC for the proposed Keystone XL project. SUMMARY: Following..., DC. Friday, October 7, 2011 Ronald Reagan Building and International Trade Center, Atrium Hall,...

  15. 14 CFR 93.337 - Requirements for operating in the DC SFRA.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Requirements for operating in the DC SFRA... TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Washington, DC Metropolitan Area Special Flight Rules Area § 93.337 Requirements for operating in the DC SFRA. A...

  16. 36 CFR 1280.60 - Where do I enter the National Archives Building in Washington, DC?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Archives Building in Washington, DC? 1280.60 Section 1280.60 Parks, Forests, and Public Property NATIONAL... for Using NARA Facilities in the Washington, DC, Area? § 1280.60 Where do I enter the National Archives Building in Washington, DC? (a) To conduct research or official business, you must enter...

  17. 77 FR 2450 - Security Zone; Potomac and Anacostia Rivers, Washington, DC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-18

    ..., DC AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is establishing a...., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. FOR FURTHER... officials will take place at the U.S. Capitol Building in Washington, DC, in close proximity to...

  18. 36 CFR 1280.60 - Where do I enter the National Archives Building in Washington, DC?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Archives Building in Washington, DC? 1280.60 Section 1280.60 Parks, Forests, and Public Property NATIONAL... for Using NARA Facilities in the Washington, DC, Area? § 1280.60 Where do I enter the National Archives Building in Washington, DC? (a) To conduct research or official business, you must enter...

  19. DC6682 AERIAL VIEW LOOKING SOUTH DOWN THE NORTH CAPITOL STREET ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DC-668-2 AERIAL VIEW LOOKING SOUTH DOWN THE NORTH CAPITOL STREET CORRIDOR FROM ABOVE THE MICHIGAN AVENUE VICINITY (Photograph has been enlarged from a 4x5 negative)ING NORTH ALONG SIXTEENTH STREET - L'Enfant-McMillan Plan of Washington, DC, Washington, District of Columbia, DC

  20. DC66841 VIEW NORTH ON THE TENTH STREET PROMENADE SHOWING THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DC-668-41 VIEW NORTH ON THE TENTH STREET PROMENADE SHOWING THE DEPARTMENT OF ENERGY BUILDING BLOCKING THE VISTA TO THE SMITHSONIAN CASTLE WITH THE BANNEKER CIRCLE (RESERVATION NO. 719) FOUNTAIN IN THE FOREGROUND - L'Enfant-McMillan Plan of Washington, DC, Washington, District of Columbia, DC

  1. DC66812 AERIAL VIEW OF THE 14TH AND 15TH STREET CORRIDORS, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DC-668-12 AERIAL VIEW OF THE 14TH AND 15TH STREET CORRIDORS, LOOKING NORTH FROM ABOVE EAST POTOMAC PARK TOWARD THE MALL AND BEYOND - L'Enfant-McMillan Plan of Washington, DC, Washington, District of Columbia, DC

  2. 77 FR 41247 - Prevailing Rate Systems; Abolishment of the Washington, DC, Special Wage Schedule for Printing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-13

    ... 3206-AM59 Prevailing Rate Systems; Abolishment of the Washington, DC, Special Wage Schedule for... Washington, DC, Federal Wage System (FWS) special wage schedule for printing and lithographic positions. Printing and lithographic employees in the Washington, DC, wage area will now be paid from the...

  3. 77 FR 68718 - Safety Zone for Fireworks Display, Upper Potomac River, Alexandria Channel; Washington, DC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-16

    ..., Alexandria Channel; Washington, DC AGENCY: Coast Guard, DHS. ACTION: Notice of proposed rulemaking. SUMMARY... fireworks display launched from a barge located within the Alexandria Channel at Washington, DC. This safety... W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590-0001. Deliveries accepted between 9 a.m....

  4. 36 CFR 1280.60 - Where do I enter the National Archives Building in Washington, DC?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Archives Building in Washington, DC? 1280.60 Section 1280.60 Parks, Forests, and Public Property NATIONAL... for Using NARA Facilities in the Washington, DC, Area? § 1280.60 Where do I enter the National Archives Building in Washington, DC? (a) To conduct research or official business, you must enter...

  5. 14 CFR 93.341 - Aircraft operations in the DC FRZ.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Aircraft operations in the DC FRZ. 93.341... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Washington, DC Metropolitan Area Special Flight Rules Area § 93.341 Aircraft operations in the DC FRZ. (a) Except as provided...

  6. DC6683 AERIAL VIEW LOOKING SOUTHWEST INTO THE CITY FROM THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DC-668-3 AERIAL VIEW LOOKING SOUTHWEST INTO THE CITY FROM THE BEND IN NORTH CAPITOL STREET IN THE MICHIGAN AVENUE VICINITY (Photograph has been enlarged from a 4x5 negative) - L'Enfant-McMillan Plan of Washington, DC, Washington, District of Columbia, DC

  7. 48 CFR 552.229-71 - Federal Excise Tax-DC Government.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 4 2013-10-01 2013-10-01 false Federal Excise Tax-DC....229-71 Federal Excise Tax—DC Government. As prescribed in 529.401-71, insert the following clause: Federal Excise Tax—DC Government (SEP 1999) If the District of Columbia cites an Internal Revenue...

  8. 78 FR 29615 - Establishment of Area Navigation (RNAV) Routes; Washington, DC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-21

    ... (RNAV) Routes; Washington, DC AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action establishes five new RNAV routes in support of the Washington, DC, Optimization of..., DC Metropolitan area airports. DATES: Effective date 0901 UTC, August 22, 2013. The Director of...

  9. 48 CFR 552.229-71 - Federal Excise Tax-DC Government.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Federal Excise Tax-DC....229-71 Federal Excise Tax—DC Government. As prescribed in 529.401-71, insert the following clause: Federal Excise Tax—DC Government (SEP 1999) If the District of Columbia cites an Internal Revenue...

  10. 77 FR 64943 - Security Zone, Potomac and Anacostia Rivers; Washington, DC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-24

    ..., DC AGENCY: Coast Guard, DHS. ACTION: Notice of proposed rulemaking. SUMMARY: The Coast Guard proposes... the Presidential Inauguration in Washington, DC from January 15, 2013 through January 24, 2013. This... W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590-0001. Deliveries accepted between 9 a.m....

  11. 76 FR 63841 - Security Zone; Potomac River, Georgetown Channel, Washington, DC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-14

    ..., Washington, DC AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is... Washington, DC, in order to safeguard high-ranking public officials from terrorist acts and incidents. This... Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except...

  12. 76 FR 34576 - Washington, DC Metropolitan Area Special Flight Rules Area; OMB Approval of Information Collection

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-14

    ... TRANSPORTATION Federal Aviation Administration 14 CFR Parts 1 and 93 RIN 2120-AI17 Washington, DC Metropolitan... certain information collection. The rule titled ``Washington, DC Metropolitan Area Special Flight Rules... Operations Airspace and AIM, 800 Independence Ave., SW., Washington, DC 20591; telephone (202)...

  13. 77 FR 70964 - Security Zone, Potomac and Anacostia Rivers; Washington, DC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-28

    ..., DC AGENCY: Coast Guard, DHS. ACTION: Supplemental notice of proposed rulemaking. SUMMARY: This action... with the Presidential Inauguration in Washington, DC from January 15, 2013 through January 24, 2013 (77... Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590-0001. Deliveries...

  14. DC6687 AERIAL VIEW OF THE SOUTHEAST QUADRANT, LOOKING NORTHWEST FROM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DC-668-7 AERIAL VIEW OF THE SOUTHEAST QUADRANT, LOOKING NORTHWEST FROM ABOVE THE ANACOSTIA RIVER (Photograph has been enlarged from a 4x5 negative) - L'Enfant-McMillan Plan of Washington, DC, Washington, District of Columbia, DC

  15. 14 CFR 93.341 - Aircraft operations in the DC FRZ.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Aircraft operations in the DC FRZ. 93.341... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Washington, DC Metropolitan Area Special Flight Rules Area § 93.341 Aircraft operations in the DC FRZ. (a) Except as provided...

  16. 78 FR 63251 - Board Meeting; November 20, 2013 in Washington, DC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-23

    ... REVIEW BOARD Board Meeting; November 20, 2013 in Washington, DC The U.S. Nuclear Waste Technical Review..., the U.S. Nuclear Waste Technical Review Board will hold a public meeting in Washington, DC, on...., Washington, DC 20037; Tel. (202) 857-3388. A block of rooms has been reserved at the hotel for...

  17. 14 CFR 93.341 - Aircraft operations in the DC FRZ.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Aircraft operations in the DC FRZ. 93.341... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Washington, DC Metropolitan Area Special Flight Rules Area § 93.341 Aircraft operations in the DC FRZ. (a) Except as provided...

  18. 36 CFR 1280.60 - Where do I enter the National Archives Building in Washington, DC?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Archives Building in Washington, DC? 1280.60 Section 1280.60 Parks, Forests, and Public Property NATIONAL... for Using NARA Facilities in the Washington, DC, Area? § 1280.60 Where do I enter the National Archives Building in Washington, DC? (a) To conduct research or official business, you must enter...

  19. 5 CFR 591.215 - Where does OPM collect prices in the COLA and DC areas?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... and DC areas? 591.215 Section 591.215 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL... Areas Cost-Of-Living Allowances § 591.215 Where does OPM collect prices in the COLA and DC areas? (a.... John. The Washington, DC, area has three survey areas: the District of Columbia, the Maryland...

  20. DC6685 AERIAL VIEW LOOKING SOUTHWEST INTO THE CITY TOWARD THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DC-668-5 AERIAL VIEW LOOKING SOUTHWEST INTO THE CITY TOWARD THE ROBERT F. KENNEDY STADIUM FROM ABOVE THE EAST SHORE OF THE ANACOSTIA RIVER (Photograph has been enlarged from a 4x5 negative) - L'Enfant-McMillan Plan of Washington, DC, Washington, District of Columbia, DC