WorldWideScience

Sample records for washington dc

  1. Washington, DC

    Science.gov (United States)

    2002-01-01

    Citizens of the United States vote today (November 7, 2000) to determine who will be the next president and vice president of the country, as well as who will fill a number of congressional and senate seats that are up for election. This image of the U.S. capital city-Washington, D.C.-was acquired on June 1 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), a Japanese sensor flying aboard NASA's Terra spacecraft. The scene encompasses an area 14 km wide by 13.7 km tall, and was made using a combination of ASTER's visible and near-infrared channels. In this image, vegetation appears red, buildings and paved areas appear light blue, and the waters of the Anacostia and Potomac Rivers are dark grey. ASTER's 15-meter spatial resolution allows us to see individual buildings, including the White House, the Jefferson Memorial, and the Washington Monument with its shadow. Image courtesy NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

  2. 49 CFR 372.219 - Washington, DC

    Science.gov (United States)

    2010-10-01

    ... and is comprised of all points as follows: (a) The municipality of Washington, D.C., itself; (b) All... Manassas, VA, and the City of Manassas Park, VA. (d) All of any municipality any part of which is within... municipality wholly surrounded, or so surrounded except for a water boundary, by the municipality of...

  3. 75 FR 20776 - Security Zone; Potomac River, Washington Channel, Washington, DC

    Science.gov (United States)

    2010-04-21

    ..., Washington, DC AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is... Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and... (NPRM) entitled ``Security Zone; Potomac River, Washington Channel, Washington, DC'' in the...

  4. 76 FR 52566 - Drawbridge Operation Regulations; Anacostia River, Washington, DC

    Science.gov (United States)

    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...

  5. 76 FR 52602 - Drawbridge Operation Regulation; Anacostia River, Washington, DC

    Science.gov (United States)

    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...

  6. 77 FR 14968 - Drawbridge Operation Regulation; Anacostia River, Washington, DC

    Science.gov (United States)

    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...

  7. Socrates in Washington, D.C.

    Science.gov (United States)

    2008-08-01

    mission.” Illustration by Jim Elmore P R O G R A M M A N A G E M E N T P H I L O S O P H Y Socrates in Washington, D.C. Maj. Dan Ward, USAF 1...status quo. “But counter to what you may have heard, turkeys don’t fear change. No, no. In fact, they love it. What they fear is criticism, so they come...sang at the top of his voice. The song was a surprisingly up-tempo rendition of Send In The Clowns . It didn’t sound half bad. Among the bronze figures

  8. 75 FR 10446 - Security Zone; Potomac River, Washington Channel, Washington, DC

    Science.gov (United States)

    2010-03-08

    ..., Washington, DC AGENCY: Coast Guard, DHS. ACTION: Notice of proposed rulemaking. SUMMARY: The Coast Guard... New Jersey Avenue, SE., Washington, DC 20590-0001. (4) Hand Delivery: Same as mail address above..., DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. We have...

  9. 75 FR 28757 - Security Zone; Potomac River, Washington Channel, Washington, DC

    Science.gov (United States)

    2010-05-24

    ..., Washington, DC AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is... Transportation, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590..., DC on Monday, May 24, 2010. To address security concerns during the event, the Captain of the...

  10. 38 CFR 3.851 - St. Elizabeths Hospital, Washington, DC.

    Science.gov (United States)

    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...

  11. 77 FR 25781 - Environmental Impact Statement; Washington, DC

    Science.gov (United States)

    2012-05-01

    ... Federal Highway Administration Environmental Impact Statement; Washington, DC AGENCY: U.S. Federal Highway... of Intent to Prepare a Draft Environmental Impact Statement (DEIS). SUMMARY: The U.S. Federal Highway... Washington, DC is issuing this notice to advise agencies and the public that a Draft Environmental Impact...

  12. 78 FR 37104 - Establishment of Area Navigation (RNAV) Routes; Washington, DC

    Science.gov (United States)

    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)...

  13. Presidential Symposia and Events: Washington, DC

    Science.gov (United States)

    Walworth, Frank

    2009-08-01

    ACS President Thomas H. Lane has designated two presidential events (both organized by Sadiq Shah, Associate Vice President, Office of Research and Economic Development, Western Kentucky University) at the Washington, DC meeting to highlight the theme: "Chemistry and Global Security: Challenges and Opportunities". The location and the timing of the meeting give ACS a unique opportunity to address questions related to chemistry and global security. The location will facilitate access to the funding agencies that can present the global security challenges and opportunities to be addressed over the next decade or so, as well as to a new administration that will be looking for ideas and a dialogue with the scientific community to set an agenda for the next four years or more. Most importantly, this is a unique opportunity for the ACS divisional program planning leadership to showcase the creative solutions of chemistry by creating programming that addresses these themes. This broad theme allows chemists from all specialties to participate by assembling innovative symposia that they feel best showcase their efforts.

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

    Science.gov (United States)

    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).

  15. Natural gas pipeline leaks across Washington, DC.

    Science.gov (United States)

    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.

  16. 36 CFR 910.13 - Urban design of Washington, DC.

    Science.gov (United States)

    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,...

  17. Parks, Trees, and Environmental Justice: Field Notes from Washington, DC

    Science.gov (United States)

    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…

  18. 78 FR 10562 - Proposed Establishment of Area Navigation (RNAV) Routes; Washington, DC

    Science.gov (United States)

    2013-02-14

    ... (RNAV) Routes; Washington, DC AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of... the Washington, DC, Optimization of Airspace and Procedures in a Metroplex (OAPM) project. The... departures from the Washington, DC Metropolitan area airports. DATES: Comments must be received on or...

  19. 78 FR 63251 - Board Meeting; November 20, 2013 in Washington, DC

    Science.gov (United States)

    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...

  20. 36 CFR 1280.60 - Where do I enter the National Archives Building in Washington, DC?

    Science.gov (United States)

    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...

  1. Drilling history core hole DC-6 Hanford, Washington

    Energy Technology Data Exchange (ETDEWEB)

    1978-06-01

    Core hole DC-6 was completed in May 1978 by Boyles Brothers Drilling Company, Spokane, Washington, under subcontract to Fenix and Scisson, Inc. The hole was cored for the US Department of Energy and the Rockwell Hanford Operations' Basalt Waste Isolation Program. Fenix and Scisson, Inc. furnished the engineering, daily supervision of the core drilling activities, and geologic core logging for hole DC-6. Core hole DC-6 is located within the boundary of the Hanford Site at the old Hanford town site. The Hanford Site coordinates for DC-6 are North 54,127.17 feet and West 17,721.00 feet. The surface elevation is approximately 402 feet above sea level. The purpose of core hole DC-6 was to core drill vertically through the basalt and interbed units for stratigraphic depth determination and core collection and to provide a borehole for hydrologic testing. The total depth of core hole DC-6 was 4336 feet. Core recovery was 98.4% of the total footage cored.

  2. 78 FR 53237 - Establishment of Area Navigation (RNAV) Routes; Washington, DC

    Science.gov (United States)

    2013-08-29

    ...) Routes; Washington, DC AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY... Services, Federal Aviation Administration, 800 Independence Avenue SW., Washington, DC 20591; telephone... Register a notice of ] proposed rulemaking (NPRM) to establish two new RNAV routes in the Washington,...

  3. 78 FR 29615 - Establishment of Area Navigation (RNAV) Routes; Washington, DC

    Science.gov (United States)

    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...

  4. 77 FR 70964 - Security Zone, Potomac and Anacostia Rivers; Washington, DC

    Science.gov (United States)

    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...

  5. 77 FR 2450 - Security Zone; Potomac and Anacostia Rivers, Washington, DC

    Science.gov (United States)

    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...

  6. 77 FR 64943 - Security Zone, Potomac and Anacostia Rivers; Washington, DC

    Science.gov (United States)

    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....

  7. Three-dimensional modeling of fecal coliform in the Tidal Basin and Washington Channel, Washington, DC.

    Science.gov (United States)

    Bai, Sen; Lung, Wu-Seng

    2006-01-01

    Fecal coliform are widely used as bacterial indicator in the United States and around the world. Fecal coliform impaired water is highly possible to be polluted by pathogenic bacteria. The Tidal Basin and Washington Channel in Washington, DC are on the Total Maximum Daily Load (TMDL) list due to the high fecal coliform level. To support TMDL development, a three-dimensional numerical model of fecal coliform was developed using the EFDC framework. The model calculates the transport of fecal coliform under the influences of flap gate operations and tidal elevation. The original EFDC code was modified to calculate the die-off of fecal coliform under the impact of temperature and solar radiation intensity. The watershed contribution is expressed as storm water inflow and the load carried by the runoff. Model results show that fecal coliform vary strongly in space in both the Tidal Basin and Washington Channel. The storm water only impacts a small area around the storm water outfall in the Tidal Basin and the impacts are negligible in the Washington Channel due to dilution. The water from the Potomac River may affect the fecal coliform level in the area close to the flap gate in the Tidal Basin. The fecal coliform level in the Washington Channel is mainly controlled by the fecal coliform level in the Anacostia River, which is located at the open boundary of the Washington Channel. The potential sediment layer storage of fecal coliform was analyzed and it was found that the sediment layer fecal coliform level could be much higher than the water column fecal coliform level and becomes a secondary source under high bottom shear stress condition. The developed model built solid connection of fecal coliform source and concentration in the water column and has been used to develop TMDL.

  8. Alcohol Outlets and Violent Crime in Washington D.C.

    Directory of Open Access Journals (Sweden)

    Pan, William K

    2010-08-01

    Full Text Available Objective: Alcohol is more likely than any other drug to be involved in substance-related violence. In 2000 violence-related and self-directed injuries accounted for an estimated $37 billion and $33 billion in productivity losses and medical treatment, respectively. A review of emergency department data revealed violence and clinically identified trauma-related injuries have the strongest correlation among alcohol-dependent injuries. At the environmental level there is a relationship between alcohol outlet density and violent crime. A limited number of studies have examined the relationship between alcohol outlet type and the components of violent crime. The aim of this study is to examine the relationship between the aggregate components of violent crime and alcohol outlet density by type of outlet.Methods: For this study we used Washington, D.C. census tract data from the 2000 census to examine neighborhood characteristics. Alcohol outlet, violent crime, and population-level data for Washington, D.C. were drawn from various official yet publicly available sources. We developed an analytic database to examine the relationship between alcohol outlet category and four types of violent crime. After estimating spatial correlation and determining spatial dependence, we used a negative binomial regression analysis to assess the alcohol availability-violent crime association, while controlling for structural correlates of violence.Results: Independent of alternative structural correlates of violent crime, including the prevalence of weapons and illicit drugs, community-level alcohol outlet density is significantly associated with assaultive violence. Outlets were significantly related to robbery, assault, and sexual offenses. In addition, the relationship among on-premise and off-premise outlets varied across violent crime categories.Conclusion: In Washington, D.C., alcohol outlet density is significantly associated with the violent crimes. The

  9. Health Hazard Evaluation Report HETA 84-004-1568, George Washington University Medical Center, Washington, DC

    Energy Technology Data Exchange (ETDEWEB)

    Gorman, R.; Seligman, P.J.

    1985-03-01

    Area air samples were analyzed for organic solvent vapors and aldehydes at the Biochemistry Department, George Washington University, Washington, DC in October 1983, and February and August 1984. The evaluation was requested by the Safety Director because of employee complaints of eye and respiratory irritation. Questionnaires were administered to 75 employees in the Biochemistry Department and 24 employees in the Pharmacology Department who served as comparisons. Humidity measurements were made. The authors note that the complaints subsided during the spring of 1984, with no explanation. They conclude that the complaints among the employees, especially on the fifth floor, were due to eye irritation. The causative agent could not be identified. Recommendations include evaluating all ventilation systems and repeating the air sampling if complaints of irritation recur.

  10. 78 FR 1753 - Security Zone, Potomac and Anacostia Rivers; Washington, DC

    Science.gov (United States)

    2013-01-09

    ..., DC AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is establishing a..., 1200 New Jersey Avenue SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday...-ranking United States officials is expected to take place at the U. S. Capitol Building in Washington,...

  11. 33 CFR 165.508 - Security Zone; Georgetown Channel, Potomac River, Washington, DC.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone; Georgetown Channel, Potomac River, Washington, DC. 165.508 Section 165.508 Navigation and Navigable Waters COAST GUARD... § 165.508 Security Zone; Georgetown Channel, Potomac River, Washington, DC. (a) Definitions. (1)...

  12. Labor Market Experiences of Central American Migrants in Washington, D.C.

    Science.gov (United States)

    Repak, Terry A.

    1993-01-01

    Explores labor market experiences of Central American men and women in Washington, DC; analyzes variables determining wage levels; and assesses employment mobility. Results from 50 individuals and 100 households illustrate striking advantages in income and mobility of men. Most migrant women in Washington, DC, are segregated into low-paid service…

  13. The Washington DC Metro Area Lightning Mapping Array

    Science.gov (United States)

    Krehbiel, P.; Rison, W.; Edens, H.; O'Connor, N.; Aulich, G.; Thomas, R.; Kieft, S.; Goodman, S.; Blakeslee, R.; Hall, J.; Bailey, J.

    2006-12-01

    During the spring and summer of 2006, a network of eight lightning mapping stations has been set up in the greater DC metropolitan area to monitor the total lightning activity in storms over Virginia, Maryland and the Washington DC area. The network is a joint project between New Mexico Tech, NASA, and NOAA/National Weather Service, with real-time data being provided to the NWS for use in their forecast and warning operations. The network utilizes newly available portable stations developed with support from the National Science Foundation. Cooperating institutions involved in hosting the mapping stations are Howard University, Montgomery County Community College in Rockville MD, NOAA/NWS's Test and Evaluation Site in Sterling, VA, College of Southern Maryland near La Plata MD, the Applied Physics Laboratory of Johns Hopkins University, Northern Virginia Community College in Annandale, VA, the University of Maryland at Baltimore County, and George Mason University (Prince William Campus) in Manassas, VA. The network is experimental in that its stations a) operate in the upper rather than the lower VHF (TV channel 10, 192-198 MHz) to reduce the radio frequency background noise associated with urban environments, and b) are linked to the central processing site via the internet rather than by dedicated wireless communication links. The central processing is done in Huntsville, AL, and updated observations are sent to the National Weather Service every 2 min. The observational data will also be available on a public website. The higher operating frequency results in a decrease in signal strength estimated to be about 15-20 dB, relative to the LMA networks being operated in northern Alabama and central Oklahoma (which operate on TV channels 5 and 3, respectively). This is offset somewhat by decreased background noise levels at many of the stations. The detection threshold levels range from about -95 dBm up to -80 dBm and the peak lightning signals typically extend 15

  14. 78 FR 4790 - Security Zone, Potomac and Anacostia Rivers; Washington, DC

    Science.gov (United States)

    2013-01-23

    ..., DC AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is establishing a... Building, 1200 New Jersey Avenue SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through..., DC'' in the Federal Register (77 FR 64943). After the NPRM was published in the Federal...

  15. Circulating Practices: Migration and Translocal Development in Washington D.C. and Cochabamba, Bolivia

    National Research Council Canada - National Science Library

    Christopher Strunk

    2013-01-01

    .... I document the movement of migrant practices between Washington D.C. and Cochabamba and the influence of monetary and non-monetary flows on Bolivian cultural practices, politics, and development...

  16. Recycling urban stormwater : 1050 K NW Street, Washington, DC

    Energy Technology Data Exchange (ETDEWEB)

    Lanier, L.G.; Beasley, N. [Timmons Group Richmond, VA (United States)

    2007-07-01

    This paper described the synergistic relationship in the innovative green roof stormwater design for 1050 K Street in Washington DC, for which LEED Gold Certification is anticipated. This 11-story office building is presently in the early stages of construction. Since the existing site is 97 per cent impervious, a complex stormwater system is an integral part of the project's sustainable design. The innovative design reduces the impervious area to 67 per cent of the site. This is attributed to complex water features and a bioretention streetscape plaza. Because of this well thought-out system, only in a major storm event will there be runoff from the property. This project connected aspects of a green roof, stormwater treatment and irrigation into one system through the application of expansive experience and skills of several designers. Each segment of the project was thoroughly evaluated in an effort to maximize the function of each. The project has provided both opportunities and challenges to coordinate science and innovation with aesthetics and educational interpretation. This paper explored the technical and visual aspects of a landscape of 4 inch and 8 inch garden roof soils, bioretention basins and a cistern. There is also a connection between the collection, storage, treatment and transport of storm water and condensate from the building cooling system. The complex water treatment strategies significantly improve the stormwater runoff rates, volumes, and quality leaving this small, urban site without negatively affecting Visual aesthetics. The green roof design involved choosing the most durable plant varieties for four seasons of coverage and flower colour while not straining the infrastructure. 7 refs., 1 tab., 4 figs.

  17. 36 CFR 1280.71 - What are the general rules for using NARA property in the Washington, DC, area?

    Science.gov (United States)

    2010-07-01

    ... Rules Apply to Use NARA Public Areas in the Washington, DC, Area? General § 1280.71 What are the general... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false What are the general rules for using NARA property in the Washington, DC, area? 1280.71 Section 1280.71 Parks, Forests,...

  18. Groundwater Site Identification Indexes for Washington D.C., Baltimore City, and the Counties of Maryland

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data sets represent 23 geographic 5-minute indexes for the counties of Maryland, one 2 1/2-minute index for Washington D.C., and 1-mile square index for...

  19. Not a Pretty Picture: Toxics in Art Supplies in Washington, DC Area Public Schools.

    Science.gov (United States)

    Gilbert, Pamela

    A study revealed that some of the art and craft supplies being used by most Washington, D.C. area public school districts (City of Alexandria, Arlington and Fairfax counties--Virginia; Montgomery and Prince George's counties--Maryland; and the District of Columbia) contained toxic ingredients which could cause serious, long-term damage, sterility,…

  20. Fear of Crime among an Immigrant Population in the Washington, DC Metropolitan Area.

    Science.gov (United States)

    Ackah, Yaw

    2000-01-01

    Studied fear of crime among Ghanaian immigrants in the Washington, D.C. area, taking aspects of Ghanaian culture into account. Survey responses of 300 immigrants showed that the majority of the Ghanaian immigrants experienced fear of crime, but those who had been urban residents in Ghana were less fearful, probably because they were already…

  1. Sidwell Friends Quaker School, Washington, DC, by KieranTimberlake Architects

    DEFF Research Database (Denmark)

    Vibæk, Kasper Sánchez; Stylsvig Madsen, Ulrik

    2012-01-01

    In 2006 the new Middle School Building on the campus of Sidwell Friends School in Washington DC was completed at a cost of $28 million. The project is a renovation and addition to a fifty-year-old educational facility transforming the building and the surrounding landscape into a green expression...

  2. Drunk Driving. Surgeon General's Workshop. Proceedings (Washington, D.C., December 14-16, 1988).

    Science.gov (United States)

    Janus Associates.

    This volume presents solutions, recommendations, and strategies in eleven interrelated areas considered at the Surgeon General's Workshop on Drunk Driving held in Washington, D.C. in December of 1988. Lists of the members of the Workshop Planning Committee and members of the federal advisory group on follow-up activities for the workshop are…

  3. Making Difficult History Public: The Pedagogy of Remembering and Forgetting in Two Washington DC Museums

    Science.gov (United States)

    Segall, Avner

    2014-01-01

    In this article, Avner Segall explores some pedagogical processes in the context of two museums in Washington, DC, that focus on difficult knowledge, the National Museum of the American Indian (NMAI) and the United States Holocaust Memorial Museum. In doing so, Segall's aim is not to explore the museums as a whole or provide a comprehensive…

  4. Making Difficult History Public: The Pedagogy of Remembering and Forgetting in Two Washington DC Museums

    Science.gov (United States)

    Segall, Avner

    2014-01-01

    In this article, Avner Segall explores some pedagogical processes in the context of two museums in Washington, DC, that focus on difficult knowledge, the National Museum of the American Indian (NMAI) and the United States Holocaust Memorial Museum. In doing so, Segall's aim is not to explore the museums as a whole or provide a comprehensive…

  5. Social Marketing and the "New" Technology: Proceedings of a Washington Roundtable (Washington, DC, March 25, 1998).

    Science.gov (United States)

    Academy for Educational Development, Washington, DC.

    This document examines some of the key issues raised during the second Washington Roundtable on Social Marketing, convened by the Academy for Educational Development (AED) in 1998. AED invited participants to examine whether the interactive technologies that are revolutionizing commercial marketing--personal computers, the Internet (especially the…

  6. Washington DC Metropolitan Area Drug Study Household and Non-Household Populations (DC-MADSH-1991)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The DC Metropolitan Area Drug Study (DCMADS) was conducted in 1991, and included special analyses of homeless and transient populations and of women delivering live...

  7. Washington DC Metropolitan Area Drug Study Homeless and Transient Population (DC-MADST-1991)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The DC Metropolitan Area Drug Study (DCMADS) was conducted in 1991, and included special analyses of homeless and transient populations and of women delivering live...

  8. Science meets public service in Washington, D.C.

    Science.gov (United States)

    Vasavada, Ashwin R.

    Same planet, different worlds—that's how many scientists see the relationship between science and government. Yet science and technology have become so infused into society that those worlds are colliding. Today, a number of national issues share a strong connection to science, from stem cells to climate change and energy to bioterrorism. For scientists who can adapt to the culture of politics, working in the collision zone can be an exciting and rewarding way to spend a year or even a career.This past year, I was one of 35 scientists in Washington serving as Congressional Science and Technology Fellows, sponsored by a number of scientific societies, including AGU. The Fellows vary widely in age and carry resumes listing Ph.D.s in not only physics, biology, and chemistry but also in Earth science, food safety, psychology, and veterinary medicine. With a group like that, weekly lunches and happy hours become the kind of broadening experience that one rarely gets in focused academic departments. And then there's the politics.

  9. Circulating Practices: Migration and Translocal Development in Washington D.C. and Cochabamba, Bolivia

    OpenAIRE

    2013-01-01

    Migrant remittances are increasingly seen as a potential form of development in the global South, but the impact of international migration on sending regions is far from straightforward. In this article, I analyze migrant communities of origin in rural Bolivia as dynamic places that are constantly reproduced through connections with other places. I document the movement of migrant practices between Washington D.C. and Cochabamba and the influence of monetary and non-monetary flows on Bolivia...

  10. Brief research report: sociodemographic factors associated with HIV status among African American women in Washington, DC

    Directory of Open Access Journals (Sweden)

    Perkins EL

    2013-09-01

    Full Text Available Emory L Perkins,1 Dexter R Voisin,2 Kesslyn A Brade Stennis1 1Department of Social Work, Bowie State University, Bowie, MD, USA; 2School of Social Service Administration, University of Chicago, Chicago, IL, USA Introduction: African American women living in Washington, DC have one of the highest Human immunodeficiency virus (HIV incidence rates in the US. However, this population has been understudied, especially as it relates to factors associated with HIV status. Methods: This cross-sectional study examined sociodemographic factors that were associated with having a negative or positive HIV status among a sample of 115 African American women between the ages of 24 and 44 years. We assessed such factors as age, education, sexual orientation, household income, sources of income, number of children, length of residency tenure in Washington, DC, and level of HIV-prevention knowledge. Results: Among the overall sample, 53 women self-identified as HIV-positive and 62 as HIV-negative. Compared to their HIV-negative counterparts, women who reported being HIV-positive were less educated, had lower household income, and had longer residency tenure in Washington, DC. There were no differences in HIV knowledge between HIV-positive and -negative study participants. Conclusion: These findings may provide important directions for targeting specific subpopulations of African Americans for HIV-prevention/intervention programs. Keywords: HIV status, African American women, sociodemographic factors

  11. Residential Energy Efficiency Research Planning Meeting Summary Report: Washington, D.C. - October 27-28, 2011

    Energy Technology Data Exchange (ETDEWEB)

    2012-02-01

    This report summarizes key findings and outcomes from the U.S. Department of Energy's Building America Residential Energy Efficiency Research Planning meeting, held on October 28-29, 2011, in Washington, D.C.

  12. Sidwell Friends Quaker School, Washington, DC, by KieranTimberlake Architects

    DEFF Research Database (Denmark)

    Vibæk, Kasper Sánchez; Stylsvig Madsen, Ulrik

    2012-01-01

    In 2006 the new Middle School Building on the campus of Sidwell Friends School in Washington DC was completed at a cost of $28 million. The project is a renovation and addition to a fifty-year-old educational facility transforming the building and the surrounding landscape into a green expression...... of the school’s ambition to create a teaching landscape in close connection to the natural environment. The project designed by KieranTimberlake Associates was awarded LEED Platinum certification, making it the first school for this age group (8-12) in the United States to receive platinum rating....

  13. Availability of Network Psychiatrists Among the Largest Health Insurance Carriers in Washington, D.C.

    Science.gov (United States)

    Blech, Benzion; West, Joyce C; Yang, Zhuoyin; Barber, Keila D; Wang, Philip; Coyle, Colleen

    2017-09-01

    Lack of access to mental health treatment remains a significant problem in the United States, even after implementation of mental health parity legislation. This study examined availability of psychiatrists listed in insurance carrier network provider databases in the Washington, D.C., area. Contact information was obtained for 1,184 psychiatrists listed in online directories for three of the largest insurance carriers serving the Washington, D.C., area. The "mystery shopper" method was used to assess the accuracy of listed contact information, new outpatient appointment availability, and average wait times for 50 psychiatrists randomly selected from each insurance directory. Most (77%) physicians were successfully contacted, meaning that someone answered the phone or returned a voice mail message, and 51% of the psychiatrists had working telephone numbers verified to be correct. Fifteen percent of the psychiatrists were accepting new outpatients with the target insurance, with average wait times of 19 days; only 7% were able to schedule an appointment within two weeks. Inaccuracy of insurance provider directories significantly affected the ability of patients to obtain timely mental care.

  14. DNA Barcoding analysis of seafood accuracy in Washington, D.C. restaurants

    Directory of Open Access Journals (Sweden)

    David B. Stern

    2017-04-01

    Full Text Available In Washington D.C., recent legislation authorizes citizens to test if products are properly represented and, if they are not, to bring a lawsuit for the benefit of the general public. Recent studies revealing the widespread phenomenon of seafood substitution across the United States make it a fertile area for consumer protection testing. DNA barcoding provides an accurate and cost-effective way to perform these tests, especially when tissue alone is available making species identification based on morphology impossible. In this study, we sequenced the 5′ barcoding region of the Cytochrome Oxidase I gene for 12 samples of vertebrate and invertebrate food items across six restaurants in Washington, D.C. and used multiple analytical methods to make identifications. These samples included several ambiguous menu listings, sequences with little genetic variation among closely related species and one sequence with no available reference sequence. Despite these challenges, we were able to make identifications for all samples and found that 33% were potentially mislabeled. While we found a high degree of mislabeling, the errors involved closely related species and we did not identify egregious substitutions as have been found in other cities. This study highlights the efficacy of DNA barcoding and robust analyses in identifying seafood items for consumer protection.

  15. DNA Barcoding analysis of seafood accuracy in Washington, D.C. restaurants.

    Science.gov (United States)

    Stern, David B; Castro Nallar, Eduardo; Rathod, Jason; Crandall, Keith A

    2017-01-01

    In Washington D.C., recent legislation authorizes citizens to test if products are properly represented and, if they are not, to bring a lawsuit for the benefit of the general public. Recent studies revealing the widespread phenomenon of seafood substitution across the United States make it a fertile area for consumer protection testing. DNA barcoding provides an accurate and cost-effective way to perform these tests, especially when tissue alone is available making species identification based on morphology impossible. In this study, we sequenced the 5' barcoding region of the Cytochrome Oxidase I gene for 12 samples of vertebrate and invertebrate food items across six restaurants in Washington, D.C. and used multiple analytical methods to make identifications. These samples included several ambiguous menu listings, sequences with little genetic variation among closely related species and one sequence with no available reference sequence. Despite these challenges, we were able to make identifications for all samples and found that 33% were potentially mislabeled. While we found a high degree of mislabeling, the errors involved closely related species and we did not identify egregious substitutions as have been found in other cities. This study highlights the efficacy of DNA barcoding and robust analyses in identifying seafood items for consumer protection.

  16. Identification With Terrorist Victims of the Washington, DC Sniper Attacks: Posttraumatic Stress and Depression.

    Science.gov (United States)

    Herberman Mash, Holly B; Ursano, Robert J; Benevides, K Nikki; Fullerton, Carol S

    2016-02-01

    In October 2002, a series of sniper attacks in the Washington, DC area left 10 people dead and 3 wounded. We examined the association between identification with terrorist victims and psychological and behavioral outcomes. Participants were 1,238 residents of the Washington, DC area (ages 18-90 years; M = 41.73, SD = 12.56) who completed the Impact of Event Scale-Revised, Patient Health Questionnaire-9, and items pertaining to identification with attack victims approximately 3 weeks following the first sniper shooting. We examined 3 types of identification with the victims: (a) as like oneself, (b) as like a friend, and (c) as like a family member. The relationships of identification to posttraumatic stress and depressive symptoms were examined using linear regression analyses. Greater total identification was associated with more posttraumatic stress and depressive symptoms (B = 0.27, p < .001, and B = 0.44, p < .001, respectively), after adjusting for demographics. Those who specifically identified with the victims as either self (B = 0.24, p < .001), friend (B = 0.30, p < .001), or family member (B = 0.27, p < .001) reported more PTSD symptoms (n = 1,101). Identifying with victims as like a friend or family member, but not as like oneself, was associated with increased depressive symptoms (B = 0.61, p < .001, and B = 0.45, p = .01, respectively; n = 1,222). Presence and type of identification play a differential role in psychological and behavioral responses during traumatic events.

  17. Circulating Practices: Migration and Translocal Development in Washington D.C. and Cochabamba, Bolivia

    Directory of Open Access Journals (Sweden)

    Christopher Strunk

    2013-09-01

    Full Text Available Migrant remittances are increasingly seen as a potential form of development in the global South, but the impact of international migration on sending regions is far from straightforward. In this article, I analyze migrant communities of origin in rural Bolivia as dynamic places that are constantly reproduced through connections with other places. I document the movement of migrant practices between Washington D.C. and Cochabamba and the influence of monetary and non-monetary flows on Bolivian cultural practices, politics, and development. I demonstrate how hometown associations and returning migrants have transferred organizational practices and political ideas about development from the United States to rural Bolivia. In addition, I explore migration’s role in struggles over belonging in Cochabamba, focusing on the efforts by migrants in Washington D.C. to stake their claim through transnational houses and collective remittance projects and on recent internal migration from other regions in Bolivia. Finally, I assess the sustainability of migrant-led development in Cochabamba. Although collaboration with migrants can strengthen the local state by providing more resources, it conditions the type of development that can take place and has yet to provide adequate opportunities for returning migrants or young people in rural Bolivia.

  18. 108th Convention of the American Psychological Association. Washington, DC, August 4-8, 2000

    Science.gov (United States)

    2000-04-01

    Washington, DC--the nation's capital--celebrates a history rich in diversity and character. One of the most popular cities for sightseeing, Washington contains countless points of interest for its visitors. The world's largest museum complex, the Smithsonian Institution, invites you to explore exhibits that highlight the scientific, cultural, political, and technological developments of the United States and its people. Visit the home to original pieces of the American heritage, such as the Declaration of Independence, the Constitution, and the Bill of Rights, that have helped to shape the way we live today. The art lovers among you will delight in the seven major art galleries. See the modern art and sculpture of the Hirshhorn Museum and the newly opened Sculpture Garden; the Sackler Gallery's collection of Asian art; and the only museum devoted to the art and culture of Africa, the National Museum of African Art. In Washington, there is music in the air, from the Kennedy Center's many stages and the clubs of Georgetown and Adams Morgan to the military bands that give concerts on the Mall. Whatever your culinary desire, be it authentic Texas chili or the finest Asian cuisine, you'll find it at one of the city's internationally famous eateries. What a perfect place for APA to convene its first annual convention of the new millennium!

  19. Comparing Cost-Effectiveness of HIV Testing Strategies: Targeted and Routine Testing in Washington, DC.

    Directory of Open Access Journals (Sweden)

    Amanda D Castel

    Full Text Available Routine HIV testing is an essential approach to identifying undiagnosed infections, linking people to care and treatment, and preventing new infections. In Washington, DC, where HIV prevalence is 2.4%, a combination of routine and targeted testing approaches has been implemented since 2006.We sought to evaluate the cost effectiveness of the District of Columbia (DC Department of Health's routine and targeted HIV testing implementation strategies. We collected HIV testing data from 3 types of DC Department of Health-funded testing sites (clinics, hospitals, and community-based organizations; collected testing and labor costs; and calculated effectiveness measures including cost per new diagnosis and cost per averted transmission.Compared to routine testing, targeted testing resulted in higher positivity rates (1.33% vs. 0.44%. Routine testing averted 34.30 transmissions per year compared to targeted testing at 17.78. The cost per new diagnosis was lower for targeted testing ($2,467 vs. $7,753 per new diagnosis as was the cost per transmission averted ($33,160 vs. $104,205. When stratified by testing site, both testing approaches were most cost effective in averting new transmissions when conducted by community based organizations ($25,037 routine; $33,123 targeted compared to hospitals or clinics.While routine testing identified more newly diagnosed infections and averted more infections than targeted testing, targeted testing is more cost effective per diagnosis and per transmission averted overall. Given the high HIV prevalence in DC, the DC Department of Health's implementation strategy should continue to encourage routine testing implementation with emphasis on a combined testing strategy among community-based organizations.

  20. Meeting Summary Advanced Light Water Reactor Fuels Industry Meeting Washington DC October 27 - 28, 2011

    Energy Technology Data Exchange (ETDEWEB)

    Not Listed

    2011-11-01

    The Advanced LWR Fuel Working Group first met in November of 2010 with the objective of looking 20 years ahead to the role that advanced fuels could play in improving light water reactor technology, such as waste reduction and economics. When the group met again in March 2011, the Fukushima incident was still unfolding. After the March meeting, the focus of the program changed to determining what we could do in the near term to improve fuel accident tolerance. Any discussion of fuels with enhanced accident tolerance will likely need to consider an advanced light water reactor with enhanced accident tolerance, along with the fuel. The Advanced LWR Fuel Working Group met in Washington D.C. on October 72-18, 2011 to continue discussions on this important topic.

  1. Demonstration of LED Retrofit Lamps at the Smithsonian American Art Museum, Washington, DC

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Naomi J.; Rosenfeld, Scott M.

    2012-06-22

    This report documents observations and results obtained from a lighting demonstration project conducted under the U.S. Department of Energy GATEWAY Solid-State Lighting (SSL) Technology Demonstration Program at the Smithsonain American Art Museum in Washington, DC. LED Lamp samples were tested in the museum workshop, temporarily installed in a gallery for feedback, and ultimately replaced all traditional incandescent lamps in one gallery of modernist art at the American Art Museum and partially replacing lamps in two galleries at the Musesum's Renwick Gallery. This report describes the selection and testing process, technology challenges, perceptions, economics, energy use, and mixed results of usign LED replacement lamps in art galleries housing national treasures.

  2. Annual SO/LIC Symposium and Exhibition (22nd) Held in Washington, DC on February 8-9, 2011

    Science.gov (United States)

    2011-02-09

    Diplomacy, and Development: Translating Policy into Operational Capability” FEBRUARY 8–9, 2011 WWW.NDIA.ORG/MEETINGS/1880 MARRIOTT WARDMAN PARK HOTEL ...Chair LOCATION & LODGING Marriott Wardman Park Hotel 2660 Woodley Road NW Washington, DC 20008 (202) 328-2000 REGISTRATION Atrium - Exhibit

  3. THE ROLE OF REMOTE SENSING AND GIS IN IDENTIFYING BURIED WORLD WAR I MUNITIONS AT THE AMERICAN UNIVERSITY, WASHINGTON, DC

    Science.gov (United States)

    During World War 1, The American University in Washington D.C. was used by the U.S. Army as an experiment station for the development and testing of a variety of battlefield munitions including chemical weapons such as Mustard Gas, Phosgene, Ricin and Lewisite, among others. Afte...

  4. THE ROLE OF REMOTE SENSING IN IDENTIFYING BURIED WORLD WAR 1 MUNITIONS AT THE AMERICAN UNIVERSITY, WASHINGTON, D.C.

    Science.gov (United States)

    During World War 1, The American University in Washington D.C. was used by the U.S. Army as an experiment station for the development and testing of a variety of battlefield munitions including chemical weapons such as Mustard Gas, Phosgene, Ricin and Lewisite, among others. Afte...

  5. THE ROLE OF REMOTE SENSING IN IDENTIFYING BURIED WORLD WAR I MUNITIONS AT THE AMERICAN UNIVERSITY, WASHINGTON, D.C.

    Science.gov (United States)

    During World War 1, The American University in Washington D.C. was used by the U.S. Army as an experiment station for the development and testing of a variety of battlefield munitions including chemical weapons such as Mustard Gas, Phosgene, Ricin and Lewisite, among others. Afte...

  6. The Effect of Inclusion Models on Special Education Student Performance in Charter Schools in Washington, D.C.

    Science.gov (United States)

    Owoh, Kendahl

    2013-01-01

    Assessment results of 52 special education students in a charter school in Washington, D.C., were used to compare instruction received in co-teaching models of inclusion and resource classrooms to determine their impact on end-of-year standardized state exams. Statistical analysis showed Grade 3-8 special education students currently receiving…

  7. DOE Advanced Controls R&D Planning Workshop, June 11, 2003, Washington DC: Workshop Results

    Energy Technology Data Exchange (ETDEWEB)

    Brambley, Michael R.; Haves, Philip; McDonald, Sean C.; Torcellini, Paul; Hansen, David G.; Holmberg, David; Roth, Kurt

    2005-04-13

    On June 11, 2003, representatives from universities, federal and state government agencies, Department of Energy national laboratories, and the private sector attended a one-day workshop in Washington, DC. The objective of the workshop was to review and provide input into DOE's assessment of the market for advanced sensors and controls technology and potential R&D pathways to enhance their success in the buildings market place. The workshop consisted of two sessions. During the morning session, participants were given an overview on the following topics: market assessment, current applications and strategies for new applications, sensors and controls, networking, security, and protocols and standards, and automated diagnostics, performance measurement, commissioning and optimal control and tools. In the sessions, workshop participants were asked to review the potential R&D pathways, identify high priority activities, and outline a five year path for each of these activities. Priorities were as follows: largest and quickest impact; best use of finite resources; greatest likelihood for market penetration; and ability to replicate results. The participants identified several promising R&D opportunities.

  8. DOE Advanced Controls R&D Planning Workshop, June 11, 2003, Washington DC: Workshop Results

    Energy Technology Data Exchange (ETDEWEB)

    Brambley, Michael R.; Haves, Philip; McDonald, Sean C.; Torcellini, Paul; Hansen, David G.; Holmberg, David; Roth, Kurt

    2005-04-13

    On June 11, 2003, representatives from universities, federal and state government agencies, Department of Energy national laboratories, and the private sector attended a one-day workshop in Washington, DC. The objective of the workshop was to review and provide input into DOE's assessment of the market for advanced sensors and controls technology and potential R&D pathways to enhance their success in the buildings market place. The workshop consisted of two sessions. During the morning session, participants were given an overview on the following topics: market assessment, current applications and strategies for new applications, sensors and controls, networking, security, and protocols and standards, and automated diagnostics, performance measurement, commissioning and optimal control and tools. In the sessions, workshop participants were asked to review the potential R&D pathways, identify high priority activities, and outline a five year path for each of these activities. Priorities were as follows: largest and quickest impact; best use of finite resources; greatest likelihood for market penetration; and ability to replicate results. The participants identified several promising R&D opportunities.

  9. Population structure of the bacterial pathogen Xylella fastidiosa among street trees in Washington D.C.

    Directory of Open Access Journals (Sweden)

    Jordan Lee Harris

    Full Text Available Bacterial leaf scorch, associated with the bacterial pathogen Xylella fastidiosa, is a widely established and problematic disease of landscape ornamentals in Washington D.C. A multi-locus sequence typing analysis was performed using 10 housekeeping loci for X. fastidiosa strains in order to better understand the epidemiology of leaf scorch disease in this municipal environment. Samples were collected from 7 different tree species located throughout the District of Columbia, consisting of 101 samples of symptomatic and asymptomatic foliage from 84 different trees. Five strains of the bacteria were identified. Consistent with prior data, these strains were host specific, with only one strain associated with members of the red oak family, one strain associated with American elm, one strain associated with American sycamore, and two strains associated with mulberry. Strains found for asymptomatic foliage were the same as strains from the symptomatic foliage on individual trees. Cross transmission of the strains was not observed at sites with multiple species of infected trees within an approx. 25 m radius of one another. X. fastidiosa strain specificity observed for each genus of tree suggests a highly specialized host-pathogen relationship.

  10. Modeling the effect of transient populations on epidemics in Washington DC

    Science.gov (United States)

    Parikh, Nidhi; Youssef, Mina; Swarup, Samarth; Eubank, Stephen

    2013-11-01

    Large numbers of transients visit big cities, where they come into contact with many people at crowded areas. However, epidemiological studies have not paid much attention to the role of this subpopulation in disease spread. We evaluate the effect of transients on epidemics by extending a synthetic population model for the Washington DC metro area to include leisure and business travelers. A synthetic population is obtained by combining multiple data sources to build a detailed minute-by-minute simulation of population interaction resulting in a contact network. We simulate an influenza-like illness over the contact network to evaluate the effects of transients on the number of infected residents. We find that there are significantly more infections when transients are considered. Since much population mixing happens at major tourism locations, we evaluate two targeted interventions: closing museums and promoting healthy behavior (such as the use of hand sanitizers, covering coughs, etc.) at museums. Surprisingly, closing museums has no beneficial effect. However, promoting healthy behavior at the museums can both reduce and delay the epidemic peak. We analytically derive the reproductive number and perform stability analysis using an ODE-based model.

  11. American Chemical Society--238th National Meeting & Exposition. Novel small molecule therapeutics. 16-20 August 2009, Washington DC, USA.

    Science.gov (United States)

    Rotella, David P

    2009-10-01

    The Novel Small Molecule Therapeutics session of the American Chemical Society 238th National Meeting and Exposition, held in Washington DC, included topics covering new therapeutic developments in CNS, anti-infective, cardiovascular and anti-inflammatory applications. This conference report highlights selected presentations on PAR2 (protease-activated receptor 2) antagonists, adenosine and P2Y receptor agonists and antagonists, antimicrobials and neuroprotective compounds.

  12. Physiologically based pharmacokinetics in Drug Development and Regulatory Science: A workshop report (Georgetown University, Washington, DC, May 29–30, 2002)

    OpenAIRE

    Rowland, Malcolm; Balant, Luc; Peck,Carl

    2004-01-01

    A 2-day workshop on “Physiologically Based Pharmacokinetics (PBPK) in Drug Development and Regulatory Science” came to a successful conclusion on May 30, 2002, in Washington, DC. More than 120 international participants from the environmental and predominantly pharmaceutical industries, Food and Drug Administration (FDA), and universities attended this workshop, organized by the Center for Drug Development Science, Georgetown University, Washington, DC. The first of its kind specifically devo...

  13. Lithologic Coring in the Lower Anacostia Tidal Watershed, Washington, D.C., July 2002

    Science.gov (United States)

    Tenbus, Frederick J.

    2003-01-01

    Little is known about the volumetric flux of ground water to the lower tidal Anacostia River, or whether ground-water flow is an important component of the contaminant load in this part of the Anacostia River. The watershed is in the eastern part of Washington, D.C., and has been subjected to over 200 years of urbanization and modifications of the river channel and nearby land areas. These anthropogenic factors, along with tidal fluctuations in the river, make ground-water data collection and interpretations difficult. The U.S. Geological Survey is cooperating with the District of Columbia Department of Health, Environmental Health Administration, Bureau of Environmental Quality, Water Quality Division, in a study to assess nonpoint-source pollution from ground water into the lower tidal Anacostia River. Lithologic cores from drilling activities conducted during July 2002 in the study area have been interpreted in the context of geologic and hydrogeologic information from previous studies in the lower Anacostia tidal watershed. These interpretations can help achieve the overall project goals of characterizing ground-water flow and contaminant load in the study area. Hydrostratigraphic units encountered during drilling generally consisted of late Pleistocene to Holocene fluvial deposits overlying Cretaceous fluvial/deltaic deposits. Cores collected in Beaverdam Creek and the Anacostia River indicated high- and low-energy environments of deposition, respectively. Two cores collected near the river showed different types of anthropogenic fill underlain by low-energy deposits, which were in turn underlain by sand and gravel. A third core collected near the river consisted primarily of sand and gravel with no artificial fill.

  14. Scaling of economic benefits from green roof implementation in Washington, DC.

    Science.gov (United States)

    Niu, Hao; Clark, Corrie; Zhou, Jiti; Adriaens, Peter

    2010-06-01

    Green roof technology is recognized for mitigating stormwater runoff and energy consumption. Methods to overcome the cost gap between green roofs and conventional roofs were recently quantified by incorporating air quality benefits. This study investigates the impact of scaling on these benefits at the city-wide scale using Washington, DC as a test bed because of the proposed targets in the 20-20-20 vision (20 million ft(2) by 2020) articulated by Casey Trees, a nonprofit organization. Building-specific stormwater benefits were analyzed assuming two proposed policy scenarios for stormwater fees ranging from 35 to 50% reduction for green roof implementation. Heat flux calculations were used to estimate building-specific energy savings for commercial buildings. To assess benefits at the city scale, stormwater infrastructure savings were based on operational savings and size reduction due to reduced stormwater volume generation. Scaled energy infrastructure benefits were calculated using two size reductions methods for air conditioners. Avoided carbon dioxide, nitrogen oxide (NO(x)), and sulfur dioxide emissions were based on reductions in electricity and natural gas consumption. Lastly, experimental and fugacity-based estimates were used to quantify the NO(x) uptake by green roofs, which was translated to health benefits using U.S. Environmental Protection Agency models. The results of the net present value (NPV) analysis showed that stormwater infrastructure benefits totaled $1.04 million (M), while fee-based stormwater benefits were $0.22-0.32 M/y. Energy savings were $0.87 M/y, while air conditioner resizing benefits were estimated at $0.02 to $0.04 M/y and avoided emissions benefits (based on current emission trading values) were $0.09 M-0.41 M/y. Over the lifetime of the green roof (40 years), the NPV is about 30-40% less than that of conventional roofs (not including green roof maintenance costs). These considerable benefits, in concert with current and

  15. Aerosol composition and variability in the Baltimore-Washington, DC region

    Science.gov (United States)

    Beyersdorf, A. J.; Ziemba, L. D.; Chen, G.; Corr, C. A.; Crawford, J. H.; Diskin, G. S.; Moore, R. H.; Thornhill, K. L.; Winstead, E. L.; Anderson, B. E.

    2015-08-01

    In order to utilize satellite-based aerosol measurements for the determination of air quality, the relationship between aerosol optical properties (wavelength-dependent, column-integrated extinction measured by satellites) and mass measurements of aerosol loading (PM2.5 used for air quality monitoring) must be understood. This connection varies with many factors including those specific to the aerosol type, such as composition, size and hygroscopicity, and to the surrounding atmosphere, such as temperature, relative humidity (RH) and altitude, all of which can vary spatially and temporally. During the DISCOVER-AQ (Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality) project, extensive in-situ atmospheric profiling in the Baltimore, MD-Washington, DC region was performed during fourteen flights in July 2011. Identical flight plans and profile locations throughout the project provide meaningful statistics for determining the variability in and correlations between aerosol loading, composition, optical properties and meteorological conditions. Measured water-soluble aerosol mass was composed primarily of ammonium sulfate (campaign average of 32 %) and organics (57 %). A distinct difference in composition was observed with high-loading days having a proportionally larger percentage of ammonium sulfate (up to 49 %) due to transport from the Ohio River Valley. This composition shift caused a change in the aerosol water-uptake potential (hygroscopicity) such that higher relative contributions of ammonium sulfate increased the bulk aerosol hygroscopicity. These days also tended to have higher relative humidity causing an increase in the water content of the aerosol. Conversely, low aerosol loading days had lower ammonium sulfate and higher black carbon contributions causing lower single scattering albedos (SSAs). The average black carbon concentrations were 240 ng m-3 in the lowest 1 km decreasing to 35 ng m-3

  16. Modeling Storm Surge and Inundation in Washington, DC, during Hurricane Isabel and the 1936 Potomac River Great Flood

    Directory of Open Access Journals (Sweden)

    Harry V. Wang

    2015-07-01

    Full Text Available Washington, DC, the capital of the U.S., is located along the Upper Tidal Potomac River, where a reliable operational model is needed for making predictions of storm surge and river-induced flooding. We set up a finite volume model using a semi-implicit, Eulerian-Lagrangian scheme on a base grid (200 m and a special feature of sub-grids (10 m, sourced with high-resolution LiDAR data and bathymetry surveys. The model domain starts at the fall line and extends 120 km downstream to Colonial Beach, VA. The model was used to simulate storm tides during the 2003 Hurricane Isabel. The water level measuring 3.1 m reached the upper tidal river in the vicinity of Washington during the peak of the storm, followed by second and third flood peaks two and four days later, resulting from river flooding coming downstream after heavy precipitation in the watershed. The modeled water level and timing were accurate in matching with the verified peak observations within 9 cm and 3 cm, and with R2 equal to 0.93 and 0.98 at the Wisconsin Avenue and Washington gauges, respectively. A simulation was also conducted for reconstructing the historical 1936 Potomac River Great Flood that inundated downtown. It was identified that the flood water, with a velocity exceeding 2.7 m/s in the downstream of Roosevelt Island, pinched through the bank northwest of East Potomac Park near DC. The modeled maximum inundation extents revealed a crescent-shaped flooding area, which was consistent with the historical surveyed flood map of the event.

  17. Incidence of prostatic calcification in blacks in Washington, D.C., and selected African cities. Correlation of specimen roentgenographs and pathologic findings. Cooperative Prostatic Research Group.

    Science.gov (United States)

    Kovi, J; Rao, M S; Heshmat, M Y; Akberzie, M E; Jackson, M A; Ogunmuyiwa, T A

    1979-10-01

    The incidence of calcification in the prostate gland of black men from Washington, D.C., and from Ibadan, Nigeria, and Accra, Ghana, West Africa, was assessed in a total of 874 consecutive, unselected prostate specimens removed at autopsy during a five-year period (1973--1978). In the combined series there was a significant positive association between prostatic calcification and age (p less than 0.001). The frequency of calcification was significantly higher in the Washington, D.C. series than in the West African series at all age levels (p less than 0.001). This difference most likely reflects the different dietary patterns of the two population groups.

  18. 2013 EFRC PI Meeting -- Science for Our Nation's Energy Future: Energy Frontier Research Centers Principal Investigators' Meeting, Washington, D.C., July 18-19, 2013

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2013-07-01

    2013 EFRC Principal Investigators’ Meeting, July 18-19, 2013 in Washington D.C. By invitation only--about 500 attendees from the EFRCs and DOE, 235 senior EFRC members and 165 EFRC early career scientists from more than 80 institutions in 31 states, 2 foreign countries and Washington D.C. Over 115 talks and 225 posters

  19. Large Dog Relinquishment to Two Municipal Facilities in New York City and Washington, D.C.: Identifying Targets for Intervention

    Directory of Open Access Journals (Sweden)

    Emily Weiss

    2014-07-01

    Full Text Available While the overall trend in euthanasia has been decreasing nationally, large dogs are at a higher risk of euthanasia than other sized dogs in most animal shelters in the United States. We hypothesized one way to increase the lives saved with respect to these large dogs is to keep them home when possible. In order to develop solutions to decrease relinquishment, a survey was developed to learn more about the reasons owners relinquish large dogs. The survey was administered to owners relinquishing their dogs at two large municipal facilities, one in New York City and one in Washington, D.C. There were 157 responses between the two facilities. We found both significant similarities and differences between respondents and their dogs from the two cities. We identified opportunities to potentially support future relinquishers and found that targets for interventions are likely different in each community.

  20. Characterization of forest fire smoke event near Washington, DC in Summer 2013 with multi-wavelength lidar

    Directory of Open Access Journals (Sweden)

    I. Veselovskii

    2014-10-01

    Full Text Available The multi-wavelength lidar technique was applied to the study of a smoke event near Washington DC on 26–28 August 2013. Satellite observations combined with transport model predictions imply that the smoke plume originated mainly from Wyoming/Idaho forest fires and its transportation to Washington DC took approximately 5 days. The NASA/GSFC multi-wavelength Mie–Raman lidar was used to measure the smoke particle intensive parameters such as extinction and backscatter Ångström exponents together with lidar ratios at 355 and 532 nm wavelengths. For interpretation of the observed vertical profiles of the backscatter Ångström exponents γβ at 355–532 nm and 532–1064 nm, numerical simulation was performed. The results indicate that for fine mode dominant aerosols, the Ångström exponents γβ (355–532 and γβ (532–1064 have essentially different dependence on the particle size and refractive index. Inversion of 3 β + 2 α lidar observations on 27–28 August provided vertical variation of the particle volume, effective radius and the real part of the refractive index through the PBL and the smoke layer. The particle effective radius decreased with height from approximately 0.27 μm inside the PBL to 0.15 μm in the smoke layer, which was situated above the PBL. Simultaneously the real part of the refractive index in the smoke layer increased to mR ≈ 1.5. The retrievals demonstrate also that the fine mode is predominant in the particle size distribution, and that the decrease of the effective radius with height is due to a shift of the fine mode toward smaller radii.

  1. Childhood sexual abuse and HIV-related risks among men who have sex with men in Washington, DC.

    Science.gov (United States)

    Phillips, Gregory; Magnus, Manya; Kuo, Irene; Rawls, Anthony; Peterson, James; Montanez, Luz; West-Ojo, Tiffany; Jia, Yujiang; Opoku, Jenevieve; Greenberg, Alan E

    2014-05-01

    Childhood sexual abuse (CSA) has been reported to be disproportionately higher among men who have sex with men (MSM) than among heterosexual men; it has also been found to be significantly positively associated with HIV status and HIV risk factors, including unprotected anal intercourse. The purpose of this study was to assess the correlates of CSA in a sample of community-recruited MSM, investigate race as a potential effect modifier, and describe the independent association between CSA and HIV infection in Washington, DC. A total of 500 MSM were recruited by venue-based sampling in 2008 as part of the National HIV Behavioral Surveillance. More than one-half of MSM identified as White, while one-third identified as Black. CSA was reported by 17.5 % of the 451 MSM, with the first instance of abuse occurring at a median age of 8.3 (interquartile range = 5.0, 11.0). In multivariable analysis, HIV-positive men were significantly more likely to report a history of CSA compared to HIV-negative men after adjusting for intimate partner violence in the last 12 months, having been arrested in the last 12 months, and depressive symptoms. HIV-positive MSM had more than four times the odds of reporting CSA after controlling for other correlates (aOR = 4.19; 95 % CI 2.26, 7.75). Despite hypothesizing that race modified the effect of CSA on HIV infection we found this was not the case in this sample. More research is needed to investigate the potential pathway between a history of CSA and HIV infection, and how this contributes to driving the HIV epidemic among MSM in Washington, DC.

  2. THER ROLE OF REMOTE SENSING AND GIS IN IDENTIFYING AND REMOVING BURIED WORLD WAR I MUNITIONS AT THE AMERICAN UNIVERSITY, WASHINGTON, DC

    Science.gov (United States)

    During World War I, The American University in Washington D.C. was used by the U.S. Am1y as an experiment station for the development and testing of a variety of battlefield munitions including chemical weapons such as Mustard Gas, Phosgene, Ricin and Lewisite, among others. Afte...

  3. THE ROLE OF THE REMOTE SENSING IN IDENTIFYING BURIED WORLD WAR I MUNITIONS AT THE AMERICAN UNIVERSITY, WASHINGTON, D.C.

    Science.gov (United States)

    During World War 1, The American University in Washington D.C. was used by the U.S. Army as an experiment station for the development and testing of a variety of battlefield munitions including chemical weapons such as Mustard Gas, Phosgene, Ricin and Lewisite, among othe...

  4. The Nonutilization of Special Transport Services by the Elderly in Urban Areas: A Case Study of Washington, D.C. Final Report and Executive Summary.

    Science.gov (United States)

    Lyons, Deborah L.; Lipowitz, Isaac

    Improving the mobility of older adults has been a major goal of transportation programs and policies for the elderly at both the federal and local levels. To examine reasons why eligible elderly individuals in urban areas do not use available special transport services, 140 elderly persons in the Washington, D.C. area were surveyed on the extent…

  5. Shaping the New World Order: International Cultural Opportunities and the Private Sector. Edited Proceedings of an International Cultural Forum (Washington, D.C., December 13, 1991).

    Science.gov (United States)

    Richardson, Malcolm, Ed.; And Others

    This publication presents the proceedings of a forum held at the U.S. State Department (Washington, D.C.) on the influence of international cultural opportunities in the new world order taking shape since the demise of Communism. The speeches, introductions, and forum discussions are offered in the order that they occurred over the course of a…

  6. The State of Digital Preservation: An International Perspective. Conference Proceedings (1st, Washington, D.C., April 24-25, 2002).

    Science.gov (United States)

    Council on Library and Information Resources, Washington, DC.

    In this collection of papers presented at "The State of Digital Preservation: An International Perspective" conference (Washington, DC, April 24-25, 2002), leading experts from the United States, the Netherlands, and Australia describe current practices and challenges in digital preservation. Contents include: "Introduction: The…

  7. A qualidade de vida de jovens portadores de espinha bífida do Children's National Medical Center – Washington DC The quality of life of adolescents with spina bifida at the Children's National Medical Center – Washington DC

    Directory of Open Access Journals (Sweden)

    Ana Helena Rotta Soares

    2006-09-01

    Full Text Available O presente artigo tem como objetivo explorar a qualidade de vida de jovens portadores de espinha bífida atendidos no Children's National Medical Center em Washington DC. A pesquisa baseia-se em uma perspectiva qualitativa que utiliza como referencial teórico central a "Teoria do estigma" e as discussões conceituais sobre as dimensões de qualidade de vida. Foram entrevistados 15 jovens do serviço acima citado, sendo que 8 deles participaram de um grupo focal construído através das questões levantadas durante entrevistas. Os discursos dos jovens em questão refletem a necessidade de categorias mais englobantes que não remetam a uma pulverização da experiência de vida. Evidenciou-se uma estrutura de desigualdade nas interações entre saudáveis e deficientes, e reproduzida pelos próprios jovens. Os resultados demonstram que o estigma se encontra presente em todas as dimensões da vida dos sujeitos, interferindo na inserção social, construção subjetiva do jovem e sua auto-estima, reforçando o papel do portador de deficiência como uma "não-pessoa". Embora a categoria sexualidade não seja priorizada em outros instrumentos para esta população, o tema se faz presente e central na discussão da experiência da vida dos mesmos.The present article explores the quality of life of adolescents with spina bifida at the Children's National Medical Center in Washington DC. The research is based on a qualitative perspective that utilizes the "Theory of stigma" as the central theoretical framework, in addition to the discussions of the concept of quality of life and its dimensions. Fifteen adolescents were interviewed at the above institution, eight of which then participated in a focal group structured through issues that emerged during this previous phase. The discourses reflected the need for more encompassing categories for quality of life that do not pulverize the life experience. The adolescent's discourses demonstrate an inequality

  8. Proceedings of the American Psychological Association, Incorporated, for the legislative year 2015: Minutes of the Annual Meeting of the Council of Representatives February 20-22, 2015, Washington, DC, and August 5 and August 7, 2015, Washington, DC, and minutes of the February, June, August, and December 2015 meetings of the Board of Directors.

    Science.gov (United States)

    Kelly, Jennifer F

    2016-01-01

    This article provides the minutes of the Annual Meeting of the Council of Representatives February 20-22, 2015, Washington, DC, and August 5 and August 7, 2015, Washington, DC, and minutes of the February, June, August, and December 2015 meetings of the Board of Directors. These minutes are the official record of the actions of the Association taken during the year by both the Board of Directors (the Board) and the Council of Representatives (Council). They are arranged in topical rather than chronological order, and subheadings are used when appropriate. (PsycINFO Database Record

  9. U.S. Department of Energy Hydrogen and Fuel Cells Program 2014 Annual Merit Review and Peer Evaluation Report: June 16-20, 2014, Washington, D.C.

    Energy Technology Data Exchange (ETDEWEB)

    2014-10-01

    The fiscal year (FY) 2014 U.S. Department of Energy (DOE) Hydrogen and Fuel Cells Program Annual Merit Review and Peer Evaluation Meeting (AMR), in conjunction with DOE's Vehicle Technologies Office AMR, was held from June 16-20, 2014, at the Washington Marriott Wardman Park in Washington, D.C. This report is a summary of comments by AMR peer reviewers about the hydrogen and fuel cell projects funded by DOE's Office of Energy Efficiency and Renewable Energy (EERE).

  10. Expanding veterinary biosurveillance in Washington, DC: The creation and utilization of an electronic-based online veterinary surveillance system.

    Science.gov (United States)

    Hennenfent, Andrew; DelVento, Vito; Davies-Cole, John; Johnson-Clarke, Fern

    2017-03-01

    To enhance the early detection of emerging infectious diseases and bioterrorism events using companion animal-based surveillance. Washington, DC, small animal veterinary facilities (n=17) were surveyed to determine interest in conducting infectious disease surveillance. Using these results, an electronic-based online reporting system was developed and launched in August 2015 to monitor rates of canine influenza, canine leptospirosis, antibiotic resistant infections, canine parvovirus, and syndromic disease trends. Nine of the 10 facilities that responded expressed interest conducting surveillance. In September 2015, 17 canine parvovirus cases were reported. In response, a campaign encouraging regular veterinary preventative care was launched and featured on local media platforms. Additionally, during the system's first year of operation it detected 5 canine leptospirosis cases and 2 antibiotic resistant infections. No canine influenza cases were reported and syndromic surveillance compliance varied, peaking during National Special Security Events. Small animal veterinarians and the general public are interested in companion animal disease surveillance. The system described can serve as a model for establishing similar systems to monitor disease trends of public health importance in pet populations and enhance biosurveillance capabilities. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Report of a workshop on nuclear forces and nonproliferation Woodrow Wilson international center for scholars, Washington, DC October 28, 2010

    Energy Technology Data Exchange (ETDEWEB)

    Pilat, Joseph F [Los Alamos National Laboratory

    2010-12-08

    A workshop sponsored by the Los Alamos National Laboratory in cooperation with the Woodrow Wilson International Center for Scholars was held at the Wilson Center in Washington, DC, on October 28, 2010. The workshop addressed evolving nuclear forces and their impacts on nonproliferation in the context of the new strategic environment, the Obama Administration's Nuclear Posture Review and the 2010 NPT Review Conference. The discussions reflected the importance of the NPR for defining the role of US nuclear forces in dealing with 21st century threats and providing guidance for National Nuclear Security Administration (NNSA) and Department of Defense (DoD) programs and, for many but not all participants, highlighted its role in the successful outcome of the NPT RevCon. There was widespread support for the NPR and its role in developing the foundations for a sustainable nuclear-weapon program that addresses nuclear weapons, infrastructure and expertise in the broader nonproliferation, disarmament and international security contexts. However, some participants raised concerns about its implementation and its long-term effectiveness and sustainability.

  12. Solar Decathlon Visitors Guide 2011, National Mall, West Potomac Park, Washington, D.C., September 23 - October 2, 2011 (Brochure)

    Energy Technology Data Exchange (ETDEWEB)

    2011-09-01

    Guide to the student-designed houses, ten contests, exhibits, and workshops of the U.S. Department of Energy 2011 Solar Decathlon, held in Washington, D.C., from September 23 through October 2, 2011. Teams of college students designed and built the solar-powered houses on display here. They represent 13 U.S. states, five countries, and four continents. Now the teams are rising to the challenge by competing in 10 contests over nine days, with the championship trophy on the line. This is their time to shine. The 2011 teams may share a common goal - to design and build the best energy-efficient house powered by the sun - but their strategies are different. One house is made of precast concrete, while another 'dances' in response to its environment. Another house is meant to sit atop a building, proving the sky's the limit for energy innovation. Whatever your idea of sustainable living may be, you are bound to find it at the Solar Decathlon.

  13. Summary of Ground-Water-Quality Data in the Anacostia River Watershed, Washington, D.C., September - December 2005

    Science.gov (United States)

    Klohe, Cheryl A.; Debrewer, Linda M.

    2007-01-01

    The U.S. Geological Survey, in cooperation with the District Department of the Environment (formerly the District of Columbia, Department of Health, Environmental Health Administration), conducted a ground-water-quality investigation in the Anacostia River watershed within Washington, D.C. Samples were collected and analyzed from 17 ground-water monitoring wells located within the study area from September through December 2005. Samples were analyzed for a variety of constituents including major ions, nutrients, volatile organic compounds, semivolatile organic compounds, pesticides and degradates, oil and grease, phenols, total polychlorinated biphenyls, and other selected constituents. The concentrations of major ions in the study area indicate that the ground water is predominantly calcium-bicarbonate type water, with some wells containing a higher percentage of milliequivalents per liter of iron (cation), and chloride or sulfate (anions). Concentrations of nitrogen were generally less than 1 milligram per liter, and concentrations of phosphorus were generally less than 0.5 milligrams per liter. Twelve of 79 pesticides and degradates were detected at 6 out of 17 wells. Volatile organic compounds (predominantly gasoline oxygenates and solvents) were detected in 9 of the 17 wells. Two semivolatile organic compounds, (bis(2-ethylhexyl) phthalate and total phenols), out of the 51 analyzed, were detected in the study area.

  14. Doctor and Patient Injuries “In the War on Drugs“: A Review of 4 individual practices in Washington DC

    Directory of Open Access Journals (Sweden)

    Alen J Salerian

    2016-05-01

    Full Text Available Background: This study reviews physician and patient injuries from the practice closures of four individual practitioners in Washington DC. Method: Retrospective review of patient records, vital statistics and relevant administrative – legal files related to the office closures. Results: Approximately 1000 patients were affected by the office closures. Among them there were 14 suicides and one premature death and 2 near-death experiences. Among physicians injury included one fatality and three serious injuries. Discussion: An alarmingly high number of suicides seems to be consistent with previous findings that some vulnerable patients may die prematurely after discontinuation of stable opiate treatment. The serious nature of physician injuries seem to indicate inhumane and unsafe treatment of physicians under the custody of DOJ and deprived of their constitutional rights of due process. Study limitations include its small size and retrospective nature. Conclusion: Regardless of why how and where the closure of a psychiatric or pain treatment related medical practice may present a high risk of injuries and fatalities among the physicians in charge and their patients triggered by the closure.

  15. Mood Sensitivity to Seasonal Changes in African College Students Living in the Greater Washington D.C. Metropolitan Area

    Directory of Open Access Journals (Sweden)

    Alvaro Guzman

    2007-01-01

    Full Text Available The purpose of this study was to estimate the degree of seasonality and prevalence of winter- and summer-type seasonal affective disorder (SAD in African immigrant college students in comparison with African American peers. A convenience sample of 246 African immigrants and 599 African Americans studying in Washington, D.C. completed the Seasonal Pattern Assessment Questionnaire (SPAQ, which was used to calculate a global seasonality score (GSS and to estimate the prevalence of winter- and summer-type SAD. Degree of seasonality was related to a complex interaction between having general awareness of SAD, ethnicity, and gender. A greater percentage of African students reported experiencing a problem with seasonal changes relative to African American students, and had summer SAD, but the groups did not differ on GSS and winter SAD. African students reported more difficulties with seasonal changes than their African American peers, which could represent a manifestation of incomplete acclimatization to a higher latitude and temperate climate. As Africans also had a greater rate of summer SAD, this argues against acclimatization to heat.

  16. Method development and survey of Sudan I–IV in palm oil and chilli spices in the Washington, DC, area

    Science.gov (United States)

    Genualdi, Susie; MacMahon, Shaun; Robbins, Katherine; Farris, Samantha; Shyong, Nicole; DeJager, Lowri

    2016-01-01

    Sudan I, II, III and IV dyes are banned for use as food colorants in the United States and European Union because they are toxic and carcinogenic. These dyes have been illegally used as food additives in products such as chilli spices and palm oil to enhance their red colour. From 2003 to 2005, the European Union made a series of decisions requiring chilli spices and palm oil imported to the European Union to contain analytical reports declaring them free of Sudan I–IV. In order for the USFDA to investigate the adulteration of palm oil and chilli spices with unapproved colour additives in the United States, a method was developed for the extraction and analysis of Sudan dyes in palm oil, and previous methods were validated for Sudan dyes in chilli spices. Both LC-DAD and LC-MS/MS methods were examined for their limitations and effectiveness in identifying adulterated samples. Method validation was performed for both chilli spices and palm oil by spiking samples known to be free of Sudan dyes at concentrations close to the limit of detection. Reproducibility, matrix effects, and selectivity of the method were also investigated. Additionally, for the first time a survey of palm oil and chilli spices was performed in the United States, specifically in the Washington, DC, area. Illegal dyes, primarily Sudan IV, were detected in palm oil at concentrations from 150 to 24 000 ng ml−1. Low concentrations (adulteration. PMID:26824489

  17. U.S. Department of Energy Hydrogen and Fuel Cells Program 2016 Annual Merit Review and Peer Evaluation Report: June 6-10, 2016, Washington, DC

    Energy Technology Data Exchange (ETDEWEB)

    Popovich, Neil

    2016-10-01

    The fiscal year 2016 U.S. Department of Energy (DOE) Hydrogen and Fuel Cells Program Annual Merit Review and Peer Evaluation Meeting (AMR), in conjunction with DOE's Vehicle Technologies Office AMR, was held from June 6-10, 2015, in Washington, D.C.. This report is a summary of comments by AMR peer reviewers about the hydrogen and fuel cell projects funded by DOE's Office of Energy Efficiency and Renewable Energy.

  18. Geology and ground-water resources of Washington, D.C., and vicinity

    Science.gov (United States)

    Johnston, Paul McKelvey

    1964-01-01

    constructed. Bored or dug wells allow greater storage capacity and are satisfactory for domestic supplies in some locations, but they are polluted easily. If not properly constructed or of sufficient depth, they may fail in dry weather. Ground-water supplies for domestic use, 5 to 10 gpm (gallons per minute), are obtainable in most places. In the Piedmont, recorded yields in drilled wells range from 0.2 to 212 gpm. In the Coastal Plain, wells yield from 1 to 800 gpm. The quality of the ground water in the report area is generally satisfactory for domestic, industrial, and irrigation use. High iron content and corrosiveness are troublesome in places. The water is soft to moderately hard--2 to 175 ppm (parts per million). Water in the Piedmont province is. dominantly the calcium and bicarbonate type; in the Coastal Plain most water is of calcium-magnesium bicarbonate type. In the Piedmont, careful location of wells with respect to the geology (rock type and structure) and to topography usually results in higher yields and may mean the difference between success and failure. In the Coastal Plain, drilled artesian wells are not affected by topography, but the yield obtained depends upon the penetration of a water-bearing sand or gravel bed at sufficient depth. The early settlers obtained water from the springs and streams, and later from dug wells. After Washington was established as the Capital in 1800, water was obtained from public and privately owned wells. Water was piped from some of the springs to government buildings and to private homes and business houses. In 1863 a diversion dam was completed in the Potomac above Great Falls and a conduit was built into the city to furnish a public water supply. This system with modifications has been in use ever since. A new diversion dam and pumping station at Little Falls was put into service in the summer of 1959. In 1961 the total pumpage from Coastal Plain aquifers in the report area was estimate

  19. Pesticides in groundwater in the Anacostia River and Rock Creek watersheds in Washington, D.C., 2005 and 2008

    Science.gov (United States)

    Koterba, Michael T.; Dieter, Cheryl A.; Miller, Cherie V.

    2010-01-01

    The U.S. Geological Survey (USGS), in cooperation with the District Department of the Environment, conducted a groundwater-quality investigation to (a) determine the presence, concentrations, and distribution of selected pesticides in groundwater, and (b) assess the presence of pesticides in groundwater in relation to selected landscape, hydrogeologic, and groundwater-quality characteristics in the shallow groundwater underlying the Anacostia River and Rock Creek watersheds in Washington, D.C. With one exception, well depths were 100 feet or less below land surface. The USGS obtained or compiled ancillary data and information on land use (2001), subsurface sediments, and groundwater samples from 17 wells in the lower Anacostia River watershed from September through December 2005, and from 14 wells in the lower Anacostia River and lower Rock Creek watersheds from August through September 2008. Twenty-seven pesticide compounds, reflecting at least 19 different types of pesticides, were detected in the groundwater samples obtained in 2005 and 2008. No fungicides were detected. In relation to the pesticides detected, degradate compounds were as or more likely to be detected than applied (parent) compounds. The detected pesticides chiefly reflected herbicides commonly used in urban settings for non-specific weed control or insecticides used for nonspecific haustellate insects (insects with specialized mouthparts for sucking liquid) or termite-specific control. Detected pesticides included a combination of pesticides currently (2008) in use, banned or under highly restricted use, and some that had replaced the banned or restricted-use pesticides. The presence of banned and restricted-use pesticides illustrates their continued persistence and resistance to complete degradation in the environment. The presence of the replacement pesticides indicates the susceptibility of the surficial aquifer to contamination irrespective of the changes in the pesticides used. A

  20. Factors Affecting Navy Working Capital Funding (NWCF) Net Operating Result: A Case Study of Naval Facilities Engineering Command Washington, Washington D.C.

    Science.gov (United States)

    2009-12-01

    deployed to Iraq as a Individual Augmentee (IA) for six months in the role of a FOB engineer of Multi- National Security Transition Command—Iraq... National Force—Iraq Comptroller office in Baghdad, Iraq as the budget and execution officer for xxi the period of one year. Capt Johnson returned to...separate organizations—Engineering Field Activity ( EFA ) Chesapeake, Public Works Center (PWC) Washington and Naval District Washington Regional

  1. Method development and survey of Sudan I-IV in palm oil and chilli spices in the Washington, DC, area.

    Science.gov (United States)

    Genualdi, Susie; MacMahon, Shaun; Robbins, Katherine; Farris, Samantha; Shyong, Nicole; DeJager, Lowri

    2016-01-01

    Sudan I, II, III and IV dyes are banned for use as food colorants in the United States and European Union because they are toxic and carcinogenic. These dyes have been illegally used as food additives in products such as chilli spices and palm oil to enhance their red colour. From 2003 to 2005, the European Union made a series of decisions requiring chilli spices and palm oil imported to the European Union to contain analytical reports declaring them free of Sudan I-IV. In order for the USFDA to investigate the adulteration of palm oil and chilli spices with unapproved colour additives in the United States, a method was developed for the extraction and analysis of Sudan dyes in palm oil, and previous methods were validated for Sudan dyes in chilli spices. Both LC-DAD and LC-MS/MS methods were examined for their limitations and effectiveness in identifying adulterated samples. Method validation was performed for both chilli spices and palm oil by spiking samples known to be free of Sudan dyes at concentrations close to the limit of detection. Reproducibility, matrix effects, and selectivity of the method were also investigated. Additionally, for the first time a survey of palm oil and chilli spices was performed in the United States, specifically in the Washington, DC, area. Illegal dyes, primarily Sudan IV, were detected in palm oil at concentrations from 150 to 24 000 ng ml(-1). Low concentrations (spices and are most likely a result of cross-contamination during preparation and storage and not intentional adulteration.

  2. Seasonal Changes in Sleep Duration in African American and African College Students Living In Washington, D.C.

    Directory of Open Access Journals (Sweden)

    Janna Volkov

    2007-01-01

    Full Text Available Duration of nocturnal melatonin secretion, a marker of “biological night” that relates to sleep duration, is longer in winter than in summer in patients with seasonal affective disorder (SAD, but not in healthy controls. In this study of African and African American college students, we hypothesized that students who met criteria for winter SAD or subsyndromal SAD (S-SAD would report sleeping longer in winter than in summer. In addition, based on our previous observation that Africans report more “problems” with change in seasons than African Americans, we expected that the seasonal changes in sleep duration would be greater in African students than in African American students. Based on Seasonal Pattern Assessment Questionnaire (SPAQ responses, African American and African college students in Washington, D.C. (N = 575 were grouped into a winter SAD/S-SAD group or a no winter diagnosis group, and winter and summer sleep length were determined. We conducted a 2 (season × 2 (sex × 2 (ethnicity × 2 (winter diagnosis group ANCOVA on reported sleep duration, controlling for age. Contrary to our hypothesis, we found that African and African American students with winter SAD/S-SAD report sleeping longer in the summer than in the winter. No differences in seasonality of sleep were found between African and African American students. Students with winter SAD or S-SAD may need to sacrifice sleep duration in the winter, when their academic functioning/efficiency may be impaired by syndromal or subsyndromal depression, in order to meet seasonally increased academic demands.

  3. Integrating Infrastructure-Relevant Climate Projections into City Planning: Learning from Boulder CO, Austin TX and Washington DC

    Science.gov (United States)

    Stoner, A. M. K.; Hayhoe, K.

    2015-12-01

    Over the coming century, climate change has the potential to impact infrastructure in many different ways, particularly in population-dense areas that depend on transportation and built environments. Many of these impacts may occur via changes in the frequency and magnitude of extremes: high and low temperature, heat waves, precipitation, coastal flooding, and storm events. Having a better idea of how the climate might change locally, both within the near future as well as toward the end of the century, can give city planners and engineers guidance when designing new structures and when repairing and fortifying existing components of buildings, bridges, highways, sewers, ports, etc. However, the type of event and the amount of damages that may be incurred are often highly specific to a given location. Over the last 10 years, we have worked with a broad range of cities, states, non-profit organizations, and federal agencies to integrate climate projections into ongoing resiliency, sustainability, and management processes. Drawing on that experience, we describe the broad steps in assimilating climate information into existing decision-making frameworks relevant to most applications, as well as highlighting many of the unique aspects of these analyses using examples from our most recent work with three very different cities - Austin TX, Boulder CO and Washington DC. From initial conversations with local experts to identify relevant thresholds to final integration of projected changes into the planning processes of these cities, these case studies highlight the utility of including future climate projections into infrastructure planning, the challenges to doing so, and the over-arching importance of communication and interaction between infrastructure experts, engineers, and scientists.

  4. Crafting glass vessels: current research on the ancient glass collections in the Freer Gallery of Art, Washington, D.C.

    Science.gov (United States)

    Nagel, Alexander; McCarthy, Blythe; Bowe, Stacy

    Our knowledge of glass production in ancient Egypt has been well augmented by the publication of recently excavated materials and glass workshops, but also by more recent materials analysis, and experiments of modern glass-makers attempting to reconstruct the production process of thin-walled coreformed glass vessels. From the mounting of a prefabricated core to the final glass product our understanding of this profession has much improved. The small but well preserved glass collection of the Freer Gallery of Art in Washington, D.C. is a valid tool for examining and studying the technology and production of ancient Egyptian core formed glass vessels. Charles Lang Freer (1854-1919) acquired most of the material from Giovanni Dattari in Cairo in 1909. Previously the glass had received only limited discussion, suggesting that most of these vessels were produced in the 18th Dynasty in the 15th and 14th centuries BCE, while others date from the Hellenistic period and later. In an ongoing project we conducted computed radiography in conjunction with qualitative x-ray fluorescence analysis on a selected group of vessels to understand further aspects of the ancient production process. This paper will provide an overview of our recent research and present our data-gathering process and preliminary results. How can the examinations of core formed glass vessels in the Freer Gallery contribute to our understanding of ancient glass production and technology? By focusing on new ways of looking at old assumptions using the Freer Gallery glass collections, we hope to increase understanding of the challenges of the production process of core-vessel technology as represented by these vessels.

  5. A Prospective Longitudinal Study of Seasonality in African Students Living in the Greater Washington, D.C. Metropolitan Area

    Directory of Open Access Journals (Sweden)

    Alvaro Guzman

    2007-01-01

    Full Text Available We conducted a prospective, longitudinal study of seasonality in a vulnerable population, i.e., African students who migrated to a temperate climate. Consistent with previous cross-sectional studies, we hypothesized lower mood and energy, and higher appetite and weight, in fall/winter than in spring/summer. Four cohorts of African students attending a year-long nursing school program without vacation in Washington, D.C., were assessed monthly for 1 year. Forty-three subjects (mean age = 33.46 ± 6.25, consisting of predominantly females (76.7%, completed the study. The cohorts began their academic program in different seasons (one each in winter, spring, summer, and fall, inherently minimizing confounding influences on seasonality, such as academic and immigration stress, as well as allowing adjustment for an order effect. At each assessment, students completed three 100-mm visual analog scales for mood, energy, and appetite, and were weighed on a digital scale. For each standardized dependent variable, a repeated measure ANOVA was used and, if a significant effect of month was identified, averages for spring/summer and fall/winter were compared using paired ttests. In addition, a mixed model for repeated measures was applied to raw (nonstandardized data. Body weight was significantly higher in fall/winter than in spring/summer (p < 0.01. No seasonal differences in mood, energy, or appetite were found. Benefiting from certain unique features of our cohorts allowing adjustment for order effects, this is the first study to identify a seasonal variation in body weight with a peak in winter using longitudinal monthly measurements.

  6. A cluster analytic examination of acculturation and health status among Asian Americans in the Washington DC metropolitan area, United States.

    Science.gov (United States)

    Lee, Sunmin; Chen, Lu; He, Xin; Miller, Matthew J; Juon, Hee-Soon

    2013-11-01

    Previous studies reported mixed findings on the relationship between acculturation and health status among Asian Americans due to different types of acculturation measures used or different Asian subgroups involved in various studies. We aim to fill the gap by applying multiple measures of acculturation in a diverse sample of Asian subgroups. A cross sectional study was conducted among Chinese, Korean and Vietnamese Americans in Washington D.C. Metropolitan Area to examine the association between health status and acculturation using multiple measures including the Suinn-Lew Asian Self-Identity Acculturation (SL-ASIA) scale, clusters based on responses to SL-ASIA, language preference, length of stay, age at arrival in the United Sates and self-identity. Three clusters (Asian (31%); Bicultural (47%); and American (22%)) were created by using a two-step hierarchical method and Bayesian Information Criterion values. Across all the measures, more acculturated individuals were significantly more likely to report good health than those who were less acculturated after adjusting for covariates. Specifically, those in the American cluster were 3.8 times (95% Confidence Interval (CI): 2.2, 6.6) more likely and those in the Bicultural cluster were 1.7 times more likely (95% CI: 1.1, 2.4) to report good health as compared to those in the Asian cluster. When the conventional standardized SL-ASIA summary score (range:-1.4 to 1.4) was used, a one point increase was associated with 2.2 times greater odds of reporting good health (95% CI: 1.5, 3.2). However, the interpretation may be challenging due to uncertainty surrounding the meaning of a one point increase in SL-ASIA summary score. Among all the measures used, acculturation clusters better approximated the acculturation process and provided us with a more accurate test of the association in the population. Variables included in this measure were more relevant for our study sample and may have worked together to capture the

  7. Occurrence and Distribution of Organic Wastewater Compounds in Rock Creek Park, Washington, D.C., 2007-08

    Science.gov (United States)

    Phelan, Daniel J.; Miller, Cherie V.

    2010-01-01

    The U.S. Geological Survey, and the National Park Service Police Aviation Group, conducted a high-resolution, low-altitude aerial thermal infrared survey of the Washington, D.C. section of Rock Creek Basin within the Park boundaries to identify specific locations where warm water was discharging from seeps or pipes to the creek. Twenty-three stream sites in Rock Creek Park were selected based on the thermal infrared images. Sites were sampled during the summers of 2007 and 2008 for the analysis of organic wastewater compounds to verify potential sources of sewage and other anthropogenic wastewater. Two sets of stormwater samples were collected, on June 27-28 and September 6, 2008, at the Rock Creek at Joyce Road water-quality station using an automated sampler that began sampling when a specified stage threshold value was exceeded. Passive-sampler devices that accumulate organic chemicals over the duration of deployment were placed in July 2008 at the five locations that had the greatest number of detections of organic wastewater compounds from the June 2007 base-flow sampling. During the 2007 base-flow synoptic sampling, there were ubiquitous low-level detections of dissolved organic wastewater indicator compounds such as DEET, caffeine, HHCB, and organophosphate flame retardants at more than half of the 23 sites sampled in Rock Creek Park. Concentrations of DEET and caffeine in the tributaries to Rock Creek were variable, but in the main stem of Rock Creek, the concentrations were constant throughout the length of the creek, which likely reflects a distributed source. Organophosphate flame retardants in the main stem of Rock Creek were detected at estimated concentrations of 0.2 micrograms per liter or less, and generally did not increase with distance downstream. Overall, concentrations of most wastewater indicators in whole-water samples in the Park were similar to the concentrations found at the upstream sampling station at the Maryland/District of Columbia

  8. The green build-out model : quantifying stormwater benefits of trees and green roofs in Washington, DC

    Energy Technology Data Exchange (ETDEWEB)

    Deutsch, B.; Whitlow, H. [Casey Trees, Washington, DC (United States); Sullivan, M.; Savineau, A.; Busiek, B. [Limno-Tech Inc., Ann Arbor, MI (United States)

    2007-07-01

    The United States Environmental Protection Agency has listed nearly all of the waters in the District of Columbia as impaired. This includes the Anacostia and Potomac rivers and Rock Creek, whose primary sources of pollution are sewer overflows and stormwater. This paper presented the research findings from the Environmental Protection Agency's Water Quality Cooperative Agreement grant entitled the Green Build-out Model. It builds upon research conducted by a public-private partnership between Casey Trees, a non-profit organization that protects tree cover in Washington DC, and Limno-Tech Inc., an environmental engineering firm that built the hydrologic and hydraulic model for the Water and Sewer Authority. Both green roofs and trees lower the volume of runoff, reduce peak rates of runoff, and improve water quality. However, these benefits have not been evaluated nor quantified on a cumulative, sewershed and city-wide basis for engineers, landscape architects, and planners to integrate green roofs and trees into solutions for stormwater permitting requirements. This research questioned how many green roofs and trees are needed to make a difference to stormwater management in the District of Columbia. It investigated the relationships between tree cover, green roof cover, larger tree boxes, and key hydrologic and hydraulic variables such as stormwater and combined sewer overflow volume, flow rate, and frequency. Reductions in pollutant loads resulting from lower stormwater volumes were also estimated along with operational savings from reduced pumping and treatment of stormwater volumes. All of the modeled green roofs were extensive green roofs with three to four inches of growth media. Extensive green roofs were assumed city-wide for their potential to reduce pollutant load from stormwater flow; operational savings from stormwater flow reductions; and, general hydrologic relationships. It was concluded that trees and green roofs should be factored into the

  9. American Chemical Society--238th National Meeting & Exposition. Developments in medicinal chemistry: part 2. 16-20 August 2009, Washington DC, USA.

    Science.gov (United States)

    Gater, Deborah; Macauley, Donald

    2009-10-01

    The 238th National Meeting and Exposition of the American Chemical Society, held in Washington DC, included topics covering new compounds and developments in the field of medicinal chemistry. This conference report highlights selected presentations on inhibitors of PARP, a heme oxygenase 1 (HO-1) inhibitor, NS3 protease inhibitors, a corticotrophin-releasing factor 1 (CRF-1) receptor antagonist, a cannabinoid receptor antagonist, diacylglycerol acyltransferase inhibitors, cathepsin and chymase receptor inhibitors, and MAPK inhibitors. Investigational drugs discussed include veliparib (Abbott Laboratories), MK-4827 (Merck & Co Inc), OB-24 (Osta Biotechnologies), BMS-339, BMS-764459, BMS-812204 and BMS-640994 (all Bristol-Myers Squibb Co), and JNJ-10311795 (Johnson & Johnson).

  10. 76 FR 31462 - Airworthiness Directives; The Boeing Company Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10...

    Science.gov (United States)

    2011-06-01

    ... 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... Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.... Applicability (c) This AD applies to all The Boeing Company Model DC-10-10, DC-10-10F, DC-10-15,......

  11. Distress of Routine Activities and Perceived Safety Associated with Post-Traumatic Stress, Depression, and Alcohol Use: 2002 Washington, DC, Sniper Attacks.

    Science.gov (United States)

    Fullerton, Carol S; Herberman Mash, Holly B; Benevides, K Nikki; Morganstein, Joshua C; Ursano, Robert J

    2015-10-01

    For over 3 weeks in October 2002, a series of sniper attacks in the Washington, DC, area left 10 people dead and 3 wounded. This study examined the relationship of distress associated with routine activities and perceived safety to psychological and behavioral responses. Participants were 1238 residents of the Washington, DC, metropolitan area (aged 18 to 90 years, mean=41.7 years) who completed an Internet survey including the Impact of Event Scale-Revised, Patient Health Questionnaire-9, and items pertaining to distress related to routine activities, perceived safety, and alcohol use. Data were collected at one time point approximately 3 weeks after the first sniper shooting and before apprehension of the suspects. Relationships of distress and perceived safety to post-traumatic stress, depressive symptoms, and increased alcohol use were examined by using linear and logistic regression analyses. Approximately 8% of the participants met the symptom criteria for probable post-traumatic stress disorder, 22% reported mild to severe depression, and 4% reported increased alcohol use during the attacks. Distress related to routine activities and perceived safety were associated with increased post-traumatic stress and depressive symptoms and alcohol use. Distress and perceived safety are associated with specific routine activities and both contribute to psychological and behavioral responses during a terrorist attack. These findings have implications for targeted information dissemination and risk communication by community leaders.

  12. Understanding Climate Policy Data Needs. NASA Carbon Monitoring System Briefing: Characterizing Flux Uncertainty, Washington D.C., 11 January 2012

    Science.gov (United States)

    Brown, Molly E.; Macauley, Molly

    2012-01-01

    Climate policy in the United States is currently guided by public-private partnerships and actions at the local and state levels. This mitigation strategy is made up of programs that focus on energy efficiency, renewable energy, agricultural practices and implementation of technologies to reduce greenhouse gases. How will policy makers know if these strategies are working, particularly at the scales at which they are being implemented? The NASA Carbon Monitoring System (CMS) will provide information on carbon dioxide fluxes derived from observations of earth's land, ocean and atmosphere used in state of the art models describing their interactions. This new modeling system could be used to assess the impact of specific policy interventions on CO2 reductions, enabling an iterative, results-oriented policy process. In January of 2012, the CMS team held a meeting with carbon policy and decision makers in Washington DC to describe the developing modeling system to policy makers. The NASA CMS will develop pilot studies to provide information across a range of spatial scales, consider carbon storage in biomass, and improve measures of the atmospheric distribution of carbon dioxide. The pilot involves multiple institutions (four NASA centers as well as several universities) and over 20 scientists in its work. This pilot study will generate CO2 flux maps for two years using observational constraints in NASA's state-of -the-art models. Bottom-up surface flux estimates will be computed using data-constrained land and ocean models; comparison of the different techniques will provide some knowledge of uncertainty in these estimates. Ensembles of atmospheric carbon distributions will be computed using an atmospheric general circulation model (GEOS-5), with perturbations to the surface fluxes and to transport. Top-down flux estimates will be computed from observed atmospheric CO2 distributions (ACOS/GOSAT retrievals) alongside the forward-model fields, in conjunction with an

  13. American Chemical Society--238th National Meeting & Exposition. Developments in medicinal chemistry: part 1. 16-20 August 2009, Washington DC, USA.

    Science.gov (United States)

    Gater, Deborah; Macauley, Donald

    2009-10-01

    The 238th National Meeting and Exposition of the American Chemical Society, held in Washington DC, included topics covering new compounds and developments in the field of medicinal chemistry. This conference report highlights selected presentations on a novel KV1.5 blocker, a state-dependent CaV2.2 antagonist, therapeutic uses of macrocycles, a novel P2X7 antagonist, developments using the StaR technology platform, the optimization of a neuropeptide S receptor antagonist, and type 1 glycine transport modulators. Investigational drugs discussed include WYE-160020 (Wyeth), Trox-1 (Neuromed Pharmaceuticals Inc), ulimorelin (Tranzyme Pharma Inc), E-32224 (Ensemble Discovery Corp) and PF-03463275 (Pfizer Inc); the discontinued compound AZD-9056 is also highlighted.

  14. "Comets, Origins, and Life:” Promoting Interdisciplinary Science in Secondary and Middle Schools in the Washington, DC and Saint Louis, MO Metro Areas

    Science.gov (United States)

    Bonev, Boncho; Gibb, E. L.; Brewer, G.; Novak, R.; Mandell, A. M.; Seaton, P.; Price, J.; Long, T.; Bahar, S.; Edwards, S. S.

    2010-10-01

    Developing a full-year program to support secondary and middle school science education is a key part of the "broader impact” component of NSF Grant AST- 0807939 (PI/Co-PI Bonev/Gibb). This program is realized at two stages: (1) a professional development course for teachers is offered during the summer; (2) during the subsequent academic year we collaborate with educators in lessons planning or curriculum development as demanded in their particular schools. We successfully offered the course “ Comets, Origins, and Life: Interdisciplinary Science in the Secondary Classroom ” (45 contact hours; 3 credits) in the summers of 2009 and 2010 at the Catholic University of America. This class demonstrates how a complex hypothesis - for the delivery of water and prebiotic organic matter to early Earth - is being tested by integrating astronomy, physics, chemistry, biology, and Earth and planetary science. Collaborations with participants from the 2009 class include curriculum development within the Earth Science program in Prince Georges county, MD and strengthening science in Washington DC public schools. Our next step is to offer our class in the Saint Louis, MO area. The main challenge in our work with educators is not to present them with "interesting information", but to fit what we offer within the very particular curriculum expectations of their school districts. These curriculum expectations often vary from district to district and sometimes from year to year. We gratefully acknowledge the support by the NSF, allowing to fully integrate our research area into education. We also gratefully acknowledge our collaborations with the Goddard Center for Astrobiology and the Howard B. Owens Science Center (both in MD) in developing our class curriculum. Educators interested in this program can contact Boncho Bonev (bonev@cua.edu; for the Washington DC and Baltimore, MD areas) and Erika Gibb (gibbe@umsl.edu; for the Saint Louis, MO area).

  15. Biomedical Challenges Presented by the American Indian, Proceedings of the Special Session of the PAHO Advisory Committee on Medical Research (7th, Washington, D.C., June 25, 1968).

    Science.gov (United States)

    Pan American Health Organization, Washington, DC.

    At each meeting of the Pan American Health Organization Advisory Committee on Medical Research, a special 1-day session is held on a topic chosen by the committee as being of particular interest. At the 7th meeting, which convened in June of 1968 in Washington, D.C., the session surveyed the origin, present distribution, and principal biological…

  16. Correlation Between Surface Area and Dissolving Properties of Lead - A Step in the Investigation of Higher than Standard Lead Concentration in Drinking Water in Washington, D.C.

    Science.gov (United States)

    Hua, M.; Garduno, L.; Mondragon, J. D.; Cuff, K. E.

    2004-12-01

    Several recently published articles by the Washington Post exposing the alarming concentration of lead in drinking water from schools and homes in the Washington D.C. area sparked our interest in the correlation between lead-containing materials used in plumbing and rate of lead solubility. Elementary children who attend schools in various regions of the District were contacted by San Francisco Bay Area- based high school students who are participants in the NSF-sponsored Environmental Science Information Technology Activities (ESITA) project. After receiving a thorough explanation of required sampling procedures, the elementary school children sent 500 ml water samples from their homes and schools to Berkeley along with information on the locations from which the water samples were collected. These water samples were analyzed for lead content at the Environmental Science Research Program laboratory at Lawrence Hall of Science. The majority of the samples contained more than 15 ppb of lead, which is the EPA action level. We hypothesize that there are three possible sources of lead in the drinking water: 1) lead pipes in the water main; 2) lead pipes in the service main; and 3) lead soldering that was often previously used to connect piping. We chose to investigate the effect of lead-based solder on the overall lead concentration in water. Using a soldering iron, we melted lead solder to create discs ranging from one to five centimeter diameter and one to thirty-six grams of mass. These discs were then placed into a beaker with 500 ml of 7.1pH distilled water and allowed to stand for 48 hours. At the end of 48 hours, the water samples were prepared for analysis using the EPA approved lead-dithizone procedure. Results showed an exponential relationship between disc surface area and the concentration of dissolved lead measured in the sample. Therefore, lead-based solder can represent a possible major source of lead contamination.

  17. Adherence with physical activity monitoring wearable devices in a community-based population: observations from the Washington, D.C., Cardiovascular Health and Needs Assessment.

    Science.gov (United States)

    Yingling, Leah R; Mitchell, Valerie; Ayers, Colby R; Peters-Lawrence, Marlene; Wallen, Gwenyth R; Brooks, Alyssa T; Troendle, James F; Adu-Brimpong, Joel; Thomas, Samantha; Henry, JaWanna; Saygbe, Johnetta N; Sampson, Dana M; Johnson, Allan A; Graham, Avis P; Graham, Lennox A; Wiley, Kenneth L; Powell-Wiley, Tiffany

    2017-01-17

    Wearable mobile health (mHealth) technologies offer approaches for targeting physical activity (PA) in resource-limited, community-based interventions. We sought to explore user characteristics of PA tracking, wearable technology among a community-based population within a health and needs assessment. In 2014-2015, we conducted the Washington, D.C., Cardiovascular Health and Needs Assessment in predominantly African-American churches among communities with higher obesity rates and lower household incomes. Participants received a mHealth PA monitor and wirelessly uploaded PA data weekly to church data collection hubs. Participants (n = 99) were 59 ± 12 years, 79% female, and 99% African-American, with a mean body mass index of 33 ± 7 kg/m(2). Eighty-one percent of participants uploaded PA data to the hub and were termed "PA device users." Though PA device users were more likely to report lower household incomes, no differences existed between device users and non-users for device ownership or technology fluency. Findings suggest that mHealth systems with a wearable device and data collection hub may feasibly target PA in resource-limited communities.

  18. Plant hydraulics as a central hub integrating plant and ecosystem function: meeting report for 'Emerging Frontiers in Plant Hydraulics' (Washington, DC, May 2015).

    Science.gov (United States)

    Sack, Lawren; Ball, Marilyn C; Brodersen, Craig; Davis, Stephen D; Des Marais, David L; Donovan, Lisa A; Givnish, Thomas J; Hacke, Uwe G; Huxman, Travis; Jansen, Steven; Jacobsen, Anna L; Johnson, Daniel M; Koch, George W; Maurel, Christophe; McCulloh, Katherine A; McDowell, Nate G; McElrone, Andrew; Meinzer, Frederick C; Melcher, Peter J; North, Gretchen; Pellegrini, Matteo; Pockman, William T; Pratt, R Brandon; Sala, Anna; Santiago, Louis S; Savage, Jessica A; Scoffoni, Christine; Sevanto, Sanna; Sperry, John; Tyerman, Stephen D; Way, Danielle; Holbrook, N Michele

    2016-09-01

    Water plays a central role in plant biology and the efficiency of water transport throughout the plant affects both photosynthetic rate and growth, an influence that scales up deterministically to the productivity of terrestrial ecosystems. Moreover, hydraulic traits mediate the ways in which plants interact with their abiotic and biotic environment. At landscape to global scale, plant hydraulic traits are important in describing the function of ecological communities and ecosystems. Plant hydraulics is increasingly recognized as a central hub within a network by which plant biology is connected to palaeobiology, agronomy, climatology, forestry, community and ecosystem ecology and earth-system science. Such grand challenges as anticipating and mitigating the impacts of climate change, and improving the security and sustainability of our food supply rely on our fundamental knowledge of how water behaves in the cells, tissues, organs, bodies and diverse communities of plants. A workshop, 'Emerging Frontiers in Plant Hydraulics' supported by the National Science Foundation, was held in Washington DC, 2015 to promote open discussion of new ideas, controversies regarding measurements and analyses, and especially, the potential for expansion of up-scaled and down-scaled inter-disciplinary research, and the strengthening of connections between plant hydraulic research, allied fields and global modelling efforts.

  19. Tobacco retail outlet advertising practices and proximity to schools, parks and public housing affect Synar underage sales violations in Washington, DC.

    Science.gov (United States)

    Kirchner, Thomas R; Villanti, Andrea C; Cantrell, Jennifer; Anesetti-Rothermel, Andrew; Ganz, Ollie; Conway, Kevin P; Vallone, Donna M; Abrams, David B

    2015-03-01

    To examine the cross-sectional association between illicit sales of tobacco to minors, Washington DC tobacco outlet advertising practices, retail store type, the demographic make-up of the area surrounding each outlet, and the proximity of each outlet to high schools, recreational parks and public housing. Seven hundred and fifty tobacco outlets in the DC area, n=347 of which were randomly selected for inspection by the Synar Inspection Program in 2009-2010. The presence of tobacco advertisements on the interior and exterior of each outlet, and illicit tobacco sales to Synar Inspection Program youth volunteers. The presence of tobacco advertisements on the exterior of gas stations was much greater than on other retail store types (OR=6.68; 95% CI 4.05 to 11.01), as was the absence of any advertisements at bars or restaurants that sold tobacco (OR=0.33; 95% CI 0.22 to 0.52). Exterior tobacco advertisements were also more likely in predominantly African-American areas of the city (OR=3.11; 95% CI 2.28 to 4.25), and particularly likely on storefronts located closer to parks (OR=1.87; 95% CI 1.06 to 3.28). Illicit sales to minors were more common at gas stations (OR=3.01; 95% CI 1.5 to 6.3), outlets that displayed exterior tobacco advertisements closer to parks (OR=3.36; 95% CI 1.38 to 8.21), and outlets located closer to high schools in majority African-American block groups (OR=1.29; 95% CI 1.07 to 1.58). Findings demonstrate that while illicit tobacco sales to minors are occurring at acceptably low rates by Synar standards, illicit sales vary considerably by retail store type, advertising approach and proximity to high schools, parks and African-American residential areas. Future work may help inform regulatory efforts to reduce youth access at the neighbourhood, city, state and national levels. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  20. Comparison of strategies to increase HIV testing among African-American gay, bisexual, and other men who have sex with men in Washington, DC.

    Science.gov (United States)

    Baytop, Chanza; Royal, Scott; Hubbard McCree, Donna; Simmons, Ron; Tregerman, Rebecca; Robinson, Carolyn; Johnson, Wayne D; McLaughlin, Mike; Price, Cristofer

    2014-01-01

    This paper presents results from a study conducted to compare the relative effectiveness of three strategies - alternate venue testing (AVT), the social network strategy (SNS), and partner counseling and referral services (PCRS; standard care) - for reaching and motivating previously undiagnosed, African-American men who have sex with men (AA MSM) to be tested for HIV. Data were collected between June 2008 and February 2010 at a gay-identified, community-based organization (CBO) serving AA MSM in Washington, DC. Men were eligible to participate if they were 18-64 years old, self-identified as black or African-American, were biologically male, and self-reported oral or anal sex with a man in the past six months. Fisher's exact test of independence was used to assess differences in demographics, testing history, HIV status and sexual behaviors across the three strategies. The final sample included 470 men who met all eligibility requirements. There were no statistically significant differences in HIV positivity rates across the three strategies. However, relative to standard care, the SNS, and (to a lesser degree) the AVT strategies were more successful in recruiting men that had never been tested. Additionally, the results indicate that each strategy recruited different subgroups of men. Specifically, heterosexually identified men and men who reported engaging in unprotected sex were most likely to be recruited via SNS. Bisexually identified men and older men were most likely to be recruited via AVT or SNS, while standard care tended to reach greater proportions of young men and homosexually identified men. These findings suggest that a combination of strategies may be the best approach for engaging African-American MSM in HIV testing.

  1. A new differential absorption lidar to measure sub-hourly fluctuation of tropospheric ozone profiles in the Baltimore-Washington DC region

    Science.gov (United States)

    Sullivan, J. T.; McGee, T. J.; Sumnicht, G. K.; Twigg, L. W.; Hoff, R. M.

    2014-04-01

    Tropospheric ozone profiles have been retrieved from the new ground based National Aeronautics and Space Administration (NASA) Goddard Space Flight Center TROPospheric OZone DIfferential Absorption Lidar (GSFC TROPOZ DIAL) in Greenbelt, MD (38.99° N, 76.84° W, 57 m a.s.l.) from 400 m to 12 km a.g.l. Current atmospheric satellite instruments cannot peer through the optically thick stratospheric ozone layer to remotely sense boundary layer tropospheric ozone. In order to monitor this lower ozone more effectively, the Tropospheric Ozone Lidar Network (TOLNet) has been developed, which currently consists of five stations across the US. The GSFC TROPOZ DIAL is based on the Differential Absorption Lidar (DIAL) technique, which currently detects two wavelengths, 289 and 299 nm. Ozone is absorbed more strongly at 289 nm than at 299 nm. The DIAL technique exploits this difference between the returned backscatter signals to obtain the ozone number density as a function of altitude. The transmitted wavelengths are generated by focusing the output of a quadrupled Nd:YAG laser beam (266 nm) into a pair of Raman cells, filled with high pressure hydrogen and deuterium. Stimulated Raman Scattering (SRS) within the focus generates a significant fraction of the pump energy at the first Stokes shift. With the knowledge of the ozone absorption coefficient at these two wavelengths, the range resolved number density can be derived. An interesting atmospheric case study involving the Stratospheric-Tropospheric Exchange (STE) of ozone is shown to emphasize the regional importance of this instrument as well as assessing the validation and calibration of data. The retrieval yields an uncertainty of 16-19% from 0-1.5 km, 10-18% from 1.5-3 km, and 11-25% from 3 km to 12 km. There are currently surface ozone measurements hourly and ozonesonde launches occasionally, but this system will be the first to make routine tropospheric ozone profile measurements in the Baltimore-Washington DC area.

  2. An intervention study to increase knowledge and use of folic acid among relatives in neural tube defect-affected families in Washington, D.C.

    Science.gov (United States)

    Byrne, Julianne; Carolan, Susan; Arcement, Rashad; Kozlowski, Matthew; Taller, Inna; Ried, Stephanie; Keating, Robert

    2005-06-01

    Little is known about the level of knowledge and use of folic acid among near relatives in U.S. families of a child with spina bifida. We hypothesized that relatives would be more knowledgeable than the general population and more likely to take folic acid. Further, we hypothesized that relatives would be more motivated by an intervention to increase their use of folic acid. We conducted an intervention study among females in families attending a hospital spina bifida clinic in Washington, DC. The 231 subjects consisted of the affected individuals, mothers, sisters, and aunts. The average age was 34 years. At baseline, most (87.4%) reported that they had heard of folic acid; 37.6% were currently taking multivitamins with folic acid and 6.9% were taking folic acid tablets. The intervention significantly increased both knowledge (to 99%) and intake of folic acid from 41.9 to 48.5%. Folic acid intake increased significantly among African-American women and women with less education, women who were older, married, with children, and nonsmokers. This intervention was successful in increasing folic acid intake among female relatives in spina bifida-affected families. By the end of the study, almost all women had heard of folic acid and folic acid use had increased by 16%. Among these women at higher than expected risk for having an affected child, this rate of intake, while more than the general population, still falls short of optimum. Fortification of food with folic acid may be the only way to ensure increased folic acid intake. (c) 2005 Wiley-Liss, Inc.

  3. Improving immunogenicity, efficacy and safety of vaccines through innovation in clinical assay development and trial design: the Phacilitate Vaccine Forum, Washington D.C. 2011.

    Science.gov (United States)

    Moldovan, Ioana R; Tary-Lehmann, Magdalena

    2011-06-01

    The 9th Annual Vaccine Forum organized by Phacilitate in Washington D.C. 2011 brought together 50+ senior level speakers and over 400 participants representing all the key stakeholders concerning vaccines. The main focus of the meeting was to define priorities in the global vaccines sector from funding to manufacturing and evaluation of vaccine efficacy. A special session was devoted to improving immunogenicity, efficacy and safety of vaccines through innovation in clinical assay development and trial design. The current regulatory approach to clinical assay specification, validation and standardization that enable more direct comparisons of efficacy between trials was illustrated by the success in meningococcal vaccine development. The industry approach to validation strategies was exemplified by a new serologic test used on the diagnostic of pneumococcal pneumonia. The application of the Animal Rule to bridge clinical and non-clinical studies in botulism has allowed significant progress in developing one of the first vaccines to seek approval under the FDA Animal Efficacy Rule. An example of pushing the boundaries in the correlation of immunological responses and efficacy points was represented by a recent cell-based influenza vaccine for which the same correlates of protection apply as for the traditional, egg-based flue vaccine. In the field of HIV phase 2b studies are underway, based on promising results obtained with some vaccine candidates. The conclusion of this session was that creativity in vaccine design and evaluation is beneficial and can lead to innovative new vaccine designs as well as to validated assays to assess vaccine efficacy.

  4. A mobile differential absorption lidar to measure sub-hourly fluctuation of tropospheric ozone profiles in the Baltimore-Washington, D.C. region

    Science.gov (United States)

    Sullivan, J. T.; McGee, T. J.; Sumnicht, G. K.; Twigg, L. W.; Hoff, R. M.

    2014-10-01

    Tropospheric ozone profiles have been retrieved from the new ground-based National Aeronautics and Space Administration (NASA) Goddard Space Flight Center TROPospheric OZone DIfferential Absorption Lidar (GSFC TROPOZ DIAL) in Greenbelt, MD (38.99° N, 76.84° W, 57 m a.s.l.), from 400 m to 12 km a.g.l. Current atmospheric satellite instruments cannot peer through the optically thick stratospheric ozone layer to remotely sense boundary layer tropospheric ozone. In order to monitor this lower ozone more effectively, the Tropospheric Ozone Lidar Network (TOLNet) has been developed, which currently consists of five stations across the US. The GSFC TROPOZ DIAL is based on the DIAL technique, which currently detects two wavelengths, 289 and 299 nm, with multiple receivers. The transmitted wavelengths are generated by focusing the output of a quadrupled Nd:YAG laser beam (266 nm) into a pair of Raman cells, filled with high-pressure hydrogen and deuterium, using helium as buffer gas. With the knowledge of the ozone absorption coefficient at these two wavelengths, the range-resolved number density can be derived. An interesting atmospheric case study involving the stratospheric-tropospheric exchange (STE) of ozone is shown, to emphasize the regional importance of this instrument as well as to assess the validation and calibration of data. There was a low amount of aerosol aloft, and an iterative aerosol correction has been performed on the retrieved data, which resulted in less than a 3 ppb correction to the final ozone concentration. The retrieval yields an uncertainty of 16-19% from 0 to 1.5 km, 10-18% from 1.5 to 3 km, and 11-25% from 3 to 12 km according to the relevant aerosol concentration aloft. There are currently surface ozone measurements hourly and ozonesonde launches occasionally, but this system will be the first to make routine tropospheric ozone profile measurements in the Baltimore-Washington, D.C. area.

  5. A New Differential Absorption Lidar to Measure Sub-Hourly Fluctuation of Tropospheric Ozone Profiles in the Baltimore - Washington D.C. Region

    Science.gov (United States)

    Sullivan, J. T.; McGee, T. J.; Sumnicht, G. K.; Twigg, L. W.; Hoff, R. M.

    2014-01-01

    Tropospheric ozone profiles have been retrieved from the new ground based National Aeronautics and Space Administration (NASA) Goddard Space Flight Center TROPospheric OZone DIfferential Absorption Lidar (GSFC TROPOZ DIAL) in Greenbelt, MD (38.99 N, 76.84 W, 57 meters ASL) from 400 m to 12 km AGL. Current atmospheric satellite instruments cannot peer through the optically thick stratospheric ozone layer to remotely sense boundary layer tropospheric ozone. In order to monitor this lower ozone more effectively, the Tropospheric Ozone Lidar Network (TOLNet) has been developed, which currently consists of five stations across the US. The GSFC TROPOZ DIAL is based on the Differential Absorption Lidar (DIAL) technique, which currently detects two wavelengths, 289 and 299 nm. Ozone is absorbed more strongly at 289 nm than at 299 nm. The DIAL technique exploits this difference between the returned backscatter signals to obtain the ozone number density as a function of altitude. The transmitted wavelengths are generated by focusing the output of a quadrupled Nd:YAG laser beam (266 nm) into a pair of Raman cells, filled with high pressure hydrogen and deuterium. Stimulated Raman Scattering (SRS) within the focus generates a significant fraction of the pump energy at the first Stokes shift. With the knowledge of the ozone absorption coefficient at these two wavelengths, the range resolved number density can be derived. An interesting atmospheric case study involving the Stratospheric-Tropospheric Exchange (STE) of ozone is shown to emphasize the regional importance of this instrument as well as assessing the validation and calibration of data. The retrieval yields an uncertainty of 16-19 percent from 0-1.5 km, 10-18 percent from 1.5-3 km, and 11-25 percent from 3 km to 12 km. There are currently surface ozone measurements hourly and ozonesonde launches occasionally, but this system will be the first to make routine tropospheric ozone profile measurements in the Baltimore-Washington

  6. 75 FR 63040 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-30, DC...

    Science.gov (United States)

    2010-10-14

    ... Corporation Model DC- 10-10, DC-10-10F, DC-10-30, DC-10-30F (KDC-10), DC-10-40, and DC-10-40F Airplanes AGENCY..., Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590. FOR FURTHER INFORMATION CONTACT... (b) None. Applicability (c) This AD applies to McDonnell Douglas Corporation Model DC- 10-10,...

  7. Implementation of a Multimodal Mobile System for Point-of-Sale Surveillance: Lessons Learned From Case Studies in Washington, DC, and New York City.

    Science.gov (United States)

    Cantrell, Jennifer; Ganz, Ollie; Ilakkuvan, Vinu; Tacelosky, Michael; Kreslake, Jennifer; Moon-Howard, Joyce; Aidala, Angela; Vallone, Donna; Anesetti-Rothermel, Andrew; Kirchner, Thomas R

    2015-01-01

    In tobacco control and other fields, point-of-sale surveillance of the retail environment is critical for understanding industry marketing of products and informing public health practice. Innovations in mobile technology can improve existing, paper-based surveillance methods, yet few studies describe in detail how to operationalize the use of technology in public health surveillance. The aims of this paper are to share implementation strategies and lessons learned from 2 tobacco, point-of-sale surveillance projects to inform and prepare public health researchers and practitioners to implement new mobile technologies in retail point-of-sale surveillance systems. From 2011 to 2013, 2 point-of-sale surveillance pilot projects were conducted in Washington, DC, and New York, New York, to capture information about the tobacco retail environment and test the feasibility of a multimodal mobile data collection system, which included capabilities for audio or video recording data, electronic photographs, electronic location data, and a centralized back-end server and dashboard. We established a preimplementation field testing process for both projects, which involved a series of rapid and iterative tests to inform decisions and establish protocols around key components of the project. Important components of field testing included choosing a mobile phone that met project criteria, establishing an efficient workflow and accessible user interfaces for each component of the system, training and providing technical support to fieldworkers, and developing processes to integrate data from multiple sources into back-end systems that can be utilized in real-time. A well-planned implementation process is critical for successful use and performance of multimodal mobile surveillance systems. Guidelines for implementation include (1) the need to establish and allow time for an iterative testing framework for resolving technical and logistical challenges; (2) developing a streamlined

  8. The impacts of aerosol loading, composition, and water uptake on aerosol extinction variability in the Baltimore-Washington, D.C. region

    Science.gov (United States)

    Beyersdorf, A. J.; Ziemba, L. D.; Chen, G.; Corr, C. A.; Crawford, J. H.; Diskin, G. S.; Moore, R. H.; Thornhill, K. L.; Winstead, E. L.; Anderson, B. E.

    2016-01-01

    In order to utilize satellite-based aerosol measurements for the determination of air quality, the relationship between aerosol optical properties (wavelength-dependent, column-integrated extinction measured by satellites) and mass measurements of aerosol loading (PM2.5 used for air quality monitoring) must be understood. This connection varies with many factors including those specific to the aerosol type - such as composition, size, and hygroscopicity - and to the surrounding atmosphere, such as temperature, relative humidity (RH), and altitude, all of which can vary spatially and temporally. During the DISCOVER-AQ (Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality) project, extensive in situ atmospheric profiling in the Baltimore, MD-Washington, D.C. region was performed during 14 flights in July 2011. Identical flight plans and profile locations throughout the project provide meaningful statistics for determining the variability in and correlations between aerosol loading, composition, optical properties, and meteorological conditions. Measured water-soluble aerosol mass was composed primarily of ammonium sulfate (campaign average of 32 %) and organics (57 %). A distinct difference in composition was observed, with high-loading days having a proportionally larger percentage of sulfate due to transport from the Ohio River Valley. This composition shift caused a change in the aerosol water-uptake potential (hygroscopicity) such that higher relative contributions of inorganics increased the bulk aerosol hygroscopicity. These days also tended to have higher relative humidity, causing an increase in the water content of the aerosol. Conversely, low-aerosol-loading days had lower sulfate and higher black carbon contributions, causing lower single-scattering albedos (SSAs). The average black carbon concentrations were 240 ng m-3 in the lowest 1 km, decreasing to 35 ng m-3 in the free troposphere (above

  9. PREFACE PASREG: The 7th International Workshop on the Processing and Applications of Superconducting (RE)BCO Large Grain Materials (Washington DC, 29-31 July 2010) PASREG: The 7th International Workshop on the Processing and Applications of Superconducting (RE)BCO Large Grain Materials (Washington DC, 29-31 July 2010)

    Science.gov (United States)

    Freyhardt, Herbert; Cardwell, David; Strasik, Mike

    2010-12-01

    Large grain, (RE)BCO bulk superconductors fabricated by top seeded melt growth (TSMG) are able to generate large magnetic fields compared to conventional, iron-based permanent magnets. Following 20 years of development, these materials are now beginning to realize their considerable potential for a variety of engineering applications such as magnetic separators, flywheel energy storage and magnetic bearings. MgB2 has also continued to emerge as a potentially important bulk superconducting material for engineering applications below 20 K due to its lack of granularity and the ease with which complex shapes of this material can be fabricated. This issue of Superconductor Science and Technology contains a selection of papers presented at the 7th International Workshop on the Processing and Applications of Superconducting (RE)BCO Large Grain Materials, including MgB2, held 29th-31sy July 2010 at the Omni Shoreham Hotel, Washington DC, USA, to report progress made in this field in the previous three year period. The workshop followed those held previously in Cambridge, UK (1997), Morioka, Japan (1999), Seattle, USA (2001), Jena, Germany (2003), Tokyo, Japan (2005) and again in Cambridge, UK (2007). The scope of the seventh PASREG workshop was extended to include processing and characterization aspects of the broader spectrum of bulk high temperature superconducting (HTS) materials, including melt-cast Bi-HTS and bulk MgB2, recent developments in the field and innovative applications of bulk HTS. A total of 38 papers were presented at this workshop, of which 30 were presented in oral form and 8 were presented as posters. The organizers wish to acknowledge the efforts of Sue Butler of the University of Houston for her local organization of the workshop. The eighth PASREG workshop will be held in Taiwan in the summer of 2012.

  10. Washington, DC Tops EPAs List of Cities with the Most Energy Star Certified Buildings/Energy efficiency leads to a stronger economy and healthier environment

    Science.gov (United States)

    WASHINGTON - The U.S. Environmental Protection Agency (EPA) has announced its eighth-annual Top Cities list, which ranks the 25 U.S. metropolitan areas with the most Energy Star certified commercial buildings in the preceding calendar year. For th

  11. National Symposium on Polymers in the Service of Man, State-of-the-Art Symposium (16th) held June 9-11, 1980, Carnegie Institution, Washington, DC

    Science.gov (United States)

    1980-01-01

    1v POLYMER SCIENTISTS RESPOND TO THE EKERGY PROBLEM Janes D. D’lanni President, American Chemical Society 1155 Sixteenth Street, fc.W. Washington...round holes in spinneret Increased sice and better methods of fabrication were accompanied by new metals, and after the austen - ltic 316 stainless

  12. 75 FR 62331 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-14, DC-9-15, and DC-9-15F...

    Science.gov (United States)

    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...

  13. 76 FR 39251 - Airworthiness Directives; The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD...

    Science.gov (United States)

    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...

  14. 76 FR 53346 - Airworthiness Directives; The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD...

    Science.gov (United States)

    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),...

  15. 76 FR 1993 - Airworthiness Directives; The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD...

    Science.gov (United States)

    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...

  16. 76 FR 41651 - Airworthiness Directives; The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD...

    Science.gov (United States)

    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),...

  17. 75 FR 68686 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-14, DC-9-15, and DC-9-15F...

    Science.gov (United States)

    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...

  18. Proceedings of the American Psychological Association for the Legislative Year 2006: Minutes of the Annual Meeting of the Council of Representatives, February 17-19, 2006, Washington, DC; and August 17 and 21, 2006, New Orleans, LA; and Minutes of the February, June, August, and December 2006 Meetings of the Board of Directors

    Science.gov (United States)

    Paige, Ruth Ullmann

    2007-01-01

    Minutes of the Annual Meeting of the Council of Representatives (February 17-19, 2006, Washington, DC; and August 17 and 21, 2006, New Orleans, LA) and of the 2006 meetings of the Board of Directors (February, June, August, and December) are provided. These minutes are the official record of the actions of the American Psychological Association…

  19. Βιβλιοκρισία του: GARY VIKAN, Early Byzantine Pilgrimage Art. Revised Edition (first published 1982. Dumbarton Oaks Byzantine Collection Publications 5, Washington DC: Dumbarton Oaks Research Library and Collection, Trustees for Harvard University, 2011

    Directory of Open Access Journals (Sweden)

    Anastasia G. YANGAKI

    2012-10-01

    Full Text Available book review: Gary Vikan, Early Byzantine Pilgrimage Art. Revised Edition (first published 1982. Dumbarton Oaks Byzantine Collection Publications 5, Washington DC: Dumbarton Oaks Research Library and Collection, Trustees for Harvard University pp. 109. ISBN: 978-0-88402-358-6.

  20. Proceedings of Colloquium 110 of the International Astronomical Union on Library and Information Services in Astronomy Held in Washington, DC on 26 July- 1 August 1988

    Science.gov (United States)

    1989-01-01

    Title --------------------. 1 037.05-020 by Fusi Pecci/3uonanno/Oorsi/Ro-ini/ at Bolo na/ Roma /Drksly I White dwarfs and lower main sequence stars in...automation networking, ENEA- D.C. STUDI, Roma . 10. Zaratiegui, M.E., 1985. Automatizacion de Ia biblioteca de la Universidad de Navarra, Uiniversidad de...colleagues. The whole body of accumulated information became universally available. A celebrated example is the famous Historia Coelestis of Tycho Brahe. An

  1. 76 FR 13543 - Airworthiness Directives; The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD...

    Science.gov (United States)

    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),...

  2. Proceedings of the International Symposium on Diamond Materials Held in Washington, DC on 5-10 May 1991. Volume 91-8

    Science.gov (United States)

    1991-05-01

    A.M. Bonnot, T. Lopez-Rios, B. Mathis & J. Leroy CHARACTERIZATION OF DC PLASMAS FOR THE CONTROL 290 OF DIAMOND DEPOSITION L.S. Plano , D.A. Stevenson...589 M.I. Landstrass, M.A. Plano , & D. Moyer THE GROWTH AND SOME PROPERTIES OF DIAMOND FILMS 597 OF P- AND N-TYPE CONDUCTIVITY OBTAINED BY...temperature was measured by a 0.125mm diame- ter chromel/alumel thermocouple in intimate contact with the crystal. The thermocou- pie was threaded through a

  3. Taste and smell function in chronic disease: a review of clinical and biochemical evaluations of taste and smell dysfunction in over 5000 patients at The Taste and Smell Clinic in Washington, DC.

    Science.gov (United States)

    Henkin, Robert I; Levy, Lucien M; Fordyce, April

    2013-01-01

    To describe systematic methods developed over 40 years among over 5000 patients at The Taste and Smell Clinic in Washington, DC to evaluate taste and smell dysfunction. A tripartite methodology was developed. First, methods to determine clinical pathology underlying the multiple disease processes responsible for taste and smell dysfunction were developed. Second, methods to determine biochemical parameters responsible for these pathologies were developed. Third, methods to implement these techniques were developed to form a unified basis upon which treatment strategies can be developed to treat these patients. Studies were performed in 5183 patients. Taste loss was present in 62% of patients, smell loss in 87%. Most patients with taste loss (52%) exhibited Type II hypogeusia; most patients with smell loss (56%) exhibited Type II hyposmia. Sensory distortions were present in 60%. Four common diagnostic entities were found: post influenza-type hyposmia and hypogeusia (27% of patients), idiopathic causes (16%), allergic rhinitis (15%) and post head injury (14%). Regardless of clinical diagnosis the major biochemical abnormality found in most patients (~70%) was diminished parotid salivary and nasal mucus secretion of cAMP and cGMP. Taste and smell dysfunctions are common clinical problems associated with chronic disease processes. These symptoms require a systematic, integrated approach to understand their multiple and complex components. The approach presented here can and has led to effective treatment. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. George Washington and the Politics of War and Revolution

    Science.gov (United States)

    2015-05-23

    58 Higginbotham, George Washington and the American Military Tradition, 8. 59 George Washington to Robert Dinwiddie, 18 July 1755, The...University, 1914): 144; quoted in Hughes, George Washington: The Rebel and The Patriot, 201. 26 the radical camp. Robert Nicholas Carter, on 24...Continental Army (Washington, DC: Center for Military History, 1983), 11. 76 George Washington to Robert Mackenzie, 9 October 1774, WGW, 3:245-246

  5. 76 FR 52225 - Airworthiness Directives; The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD...

    Science.gov (United States)

    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),...

  6. Water quality in the Anacostia River, Maryland and Rock Creek, Washington, D.C.: Continuous and discrete monitoring with simulations to estimate concentrations and yields of nutrients, suspended sediment, and bacteria

    Science.gov (United States)

    Miller, Cherie V.; Chanat, Jeffrey G.; Bell, Joseph M.

    2013-01-01

    Concentrations and loading estimates for nutrients, suspended sediment, and E. coli bacteria were summarized for three water-quality monitoring stations on the Anacostia River in Maryland and one station on Rock Creek in Washington, D.C. Both streams are tributaries to the Potomac River in the Washington, D.C. metropolitan area and contribute to the Chesapeake Bay estuary. Two stations on the Anacostia River, Northeast Branch at Riverdale, Maryland and Northwest Branch near Hyattsville, Maryland, have been monitored for water quality during the study period from 2003 to 2011 and are located near the shift from nontidal to tidal conditions near Bladensburg, Maryland. A station on Paint Branch is nested above the station on the Northeast Branch Anacostia River, and has slightly less developed land cover than the Northeast and Northwest Branch stations. The Rock Creek station is located in Rock Creek Park, but the land cover in the watershed surrounding the park is urbanized. Stepwise log-linear regression models were developed to estimate the concentrations of suspended sediment, total nitrogen, total phosphorus, and E. coli bacteria from continuous field monitors. Turbidity was the strongest predictor variable for all water-quality parameters. For bacteria, water temperature improved the models enough to be included as a second predictor variable due to the strong dependence of stream metabolism on temperature. Coefficients of determination (R2) for the models were highest for log concentrations of suspended sediment (0.9) and total phosphorus (0.8 to 0.9), followed by E. coli bacteria (0.75 to 0.8), and total nitrogen (0.6). Water-quality data provided baselines for conditions prior to accelerated implementation of multiple stormwater controls in the watersheds. Counties are currently in the process of enhancing stormwater controls in both watersheds. Annual yields were estimated for suspended sediment, total nitrogen, total phosphorus, and E. coli bacteria using

  7. Attitudes, perceptions, and behaviors toward HIV testing among African American and East African immigrant women in Washington, D.C.: Implications for targeted HIV testing promotion and communication strategies

    Science.gov (United States)

    De Jesus, Maria; Carrete, Claudia; Maine, Cathleen; Nalls, Patricia

    2015-01-01

    Objectives The objective of the study was to examine and compare the HIV testing attitudes, perceptions, and behaviors between African American and East African immigrant women in the Washington, D.C. Metropolitan area. Methods Adopting an inductive, qualitative methodological approach, we conducted a total of 40 in-depth, semi-structured interviews between October 2012 and March 2013. Qualitative thematic analysis was used to analyze the data. Results Overall, African American women held more favorable views toward HIV testing than East African immigrant women. Very few East African immigrant women sought HIV testing intentionally. The majority of East African participants were tested inadvertently, while others tested for immigration- or employment-related purposes. There were many barriers that impede women from seeking an HIV test including: negative assumptions (e.g., ‘Getting an HIV test implies that I am HIV positive’); negative emotions (e.g., ‘Fear of being diagnosed with HIV and what this will mean for me’); and potential negative reactions from partner or others (e.g., ‘Getting an HIV test can signal distrust, disrespect, or infidelity’). There were nuances in how each group articulated some of these barriers and East African women expressed unique concerns that originated from experiences in their home countries. Conclusions The study shed light into the complexity of factors that constrain women from presenting themselves voluntarily for an HIV test and highlighted the nuances between African American and East African perceptions. Implications of findings for effective targeted HIV screening promotion and communication strategies among these groups of women are discussed. PMID:25897146

  8. Congenital Plasmodium falciparum Malaria in Washington, DC.

    Science.gov (United States)

    Del Castillo, Melissa; Szymanski, Ann Marie; Slovin, Ariella; Wong, Edward C C; DeBiasi, Roberta L

    2017-01-11

    Congenital malaria is rare in the United States, but is an important diagnosis to consider when evaluating febrile infants. Herein, we describe a case of congenital Plasmodium falciparum malaria in a 2-week-old infant born in the United States to a mother who had emigrated from Nigeria 3 months before delivery. © The American Society of Tropical Medicine and Hygiene.

  9. Center for Applied Linguistics, Washington DC, USA

    Science.gov (United States)

    Sugarman, Julie; Fee, Molly; Donovan, Anne

    2015-01-01

    The Center for Applied Linguistics (CAL) is a private, nonprofit organization with over 50 years' experience in the application of research on language and culture to educational and societal concerns. CAL carries out its mission to improve communication through better understanding of language and culture by engaging in a variety of projects in…

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

    Science.gov (United States)

    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...

  11. ALA 2010: Where to Eat in DC

    Science.gov (United States)

    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…

  12. Advanced DC/DC converters

    CERN Document Server

    Luo, Fang Lin

    2003-01-01

    INTRODUCTIONHistorical ReviewMultiple Quadrant ChoppersPump CircuitsDevelopment of DC/DC Conversion TechniqueCategorize Prototypes and DC/DC Converters Family TreeVOLTAGE-LIFT CONVERTERSIntroductionSeven Self-Lift ConvertersPositive Output Luo-ConvertersNegative Output Luo-ConvertersModified Positive Output Luo-Converters Double Output Luo-ConvertersPOSITIVE OUTPUT SUPER-LIFT LUO-CONVERTERS IntroductionMain SeriesAdditional SeriesEnhanced Series Re-Enhanced Series Multiple-Enhanced Series Summary of Positive Output

  13. DC + RSL

    DEFF Research Database (Denmark)

    Haxthausen, Anne

    1996-01-01

    This document gives some initial ideas of how the Duration Calculus (DC) can be integrated with the RAISE Specification Language (RSL).......This document gives some initial ideas of how the Duration Calculus (DC) can be integrated with the RAISE Specification Language (RSL)....

  14. "20 years of progress in highway safety" : verslag van the Eleventh International Technical Conference on Experimental Safety Vehicles ESV, Washington D.C., 12-15 May 1987 : achtergronden en overzicht van de ontwikkelingen tot juli 1988.

    NARCIS (Netherlands)

    Kampen, L.T.B. van

    1988-01-01

    A report of a visit to the 'eleventh international conference on experimental safety vehicles, washington, 12-15 may 1987' is given in this publication. Some of the technical papers presented at the conference are described and commented upon: (the opening address, the status reports and the panel d

  15. "20 years of progress in highway safety" : verslag van the Eleventh International Technical Conference on Experimental Safety Vehicles ESV, Washington D.C., 12-15 May 1987 : achtergronden en overzicht van de ontwikkelingen tot juli 1988.

    OpenAIRE

    Kampen, L.T.B. van

    1988-01-01

    A report of a visit to the 'eleventh international conference on experimental safety vehicles, washington, 12-15 may 1987' is given in this publication. Some of the technical papers presented at the conference are described and commented upon: (the opening address, the status reports and the panel discussions). The following subjects are emphasised: occupant protection for side impact; accident investigation and data analysis; biomechanics and dummy development; crash avoidance; occupant prot...

  16. Simplified dc to dc converter

    Science.gov (United States)

    Gruber, R. P. (Inventor)

    1984-01-01

    A dc to dc converter which can start with a shorted output and which regulates output voltage and current is described. Voltage controlled switches directed current through the primary of a transformer the secondary of which includes virtual reactance. The switching frequency of the switches is appropriately varied to increase the voltage drop across the virtual reactance in the secondary winding to which there is connected a low impedance load. A starting circuit suitable for voltage switching devices is provided.

  17. 75 FR 11583 - District of Columbia Disaster #DC-00001

    Science.gov (United States)

    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...

  18. 75 FR 17791 - District of Columbia Disaster # DC-00002

    Science.gov (United States)

    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...

  19. PWM DC/DC Converter

    OpenAIRE

    Chen, Juan

    2008-01-01

    This report is the result of a Master Thesis work done at Seaward Electronics Inc. in Beijing, China from June to December in 2007. The main goal for this thesis is to verify and improve the performance of Honey-PWM DC-DC converter, which has been fabricated by a standard 0.6um CMOS processes. The project was started with studying of Buck converter structure. After the understanding of the converter structure, the project goes in to the analyses phase for each sub-cells, including the theory,...

  20. Drilling history core hole DC-4

    Energy Technology Data Exchange (ETDEWEB)

    1978-12-01

    Core hole DC-4 was completed at a depth of 3998 feet in December, 1978 by Boyles Brothers Drilling Company, Spokane, Washington, under subcontract to Fenix and Scission, Inc. The hole was cored for the US Department of Energy and the Rockwell Hanford Operations' Basalt Waste Isolation Program. Fenix and Sicsson, Inc. furnished the engineering, daily supervision of the cable tool and core drilling activities, and geological core logging for DC-4. Core hole DC-4 is located on the Hanford Site about 3 miles east of the Yakima Barricade and approximately 103 feet southwest of rotary hole DC-5, which was completed to 3990 feet in February, 1978. Hanford Site coordinates reported for hole DC-4 are north 49,385.62 feet and west 85,207.63 feet, and Washington State coordinates are north 454,468.73 feet and east 2,209,990.87 feet. No elevation survey is available for hole DC-4, but it is approximately 745 feet above mean sea level based upon the survey of hole DC-5, which has a reported elevation of 745.16 feet on the top of the 3-inch flange. The purpose of core hole DC-4 was to core drill vertically through the basalt and interbed units for stratigraphic depth determination and core collection, and to provide a borehole for hydrologic testing, cross-hole seismic shear, and pressure wave velocity studies with rotary hole DC-5. Hole DC-4 was drilled through the overburden into basalt bedrock by cable tool methods (0-623 feet) and continuously cored through the final interval (623 to 3998 feet).Core recovery was 95.8 percent of the total footage cored.

  1. Drilling history core hole DC-8

    Energy Technology Data Exchange (ETDEWEB)

    1978-10-01

    Core hole DC-8 was completed in August, 1978 by Boyles Brothers Drilling Company, Spokane, Washington, under subcontract to Fenix and Scission, Inc. The hole was cored for the US Department of Energy and the Rockwell Hanford Operations' Basalt Waste Isolation Program. Fenix and Scisson, Inc. furnished the engineering, daily supervision of the core drilling activities, and geologic core logging for hole DC-8. Core hole DC-8 is located on the Hanford Site near the Wye Barricade and 50 feet northwest of rotary hole DC-7. The Hanford Site vation coordinates for DC-8 are North 14,955.94 feet and West 14,861.92 coordinates for DC-8 are North 14,955.94 feet and West 14,861.92 mean sea level. The purpose of core hole DC-8 was to core drill vertically through the basalt and interbed units for stratigraphic depth determination and core collection, and to provide a borehole for hydrologic testing and cross-hole seismic shear and pressure wave velocity studies with rotary hole DC-7. The total depth of core hole DC-8 was 4100.5 feet. Core recovery exceeded 97 percent of the total footage cored.

  2. Isolerad DC/DC-omvandlare

    OpenAIRE

    Andersson, Martin

    2011-01-01

    1 SammanfattningCrossControl är ett företag som bland annat tillverkar integrerade datorlösningar. Datorerna drivs normalt med 18-30 VDC och förbrukar som mest 50W. Datorerna säljs till flertalet olika kunder som monterar dem i allt från skogsmaskiner till tåg. I de olika fordonen varierar spänningen i de befintliga elnäten. Detta skapar behovet av att omvandla spänningen till en nivå som datorerna klarar av. En sådan apparat kallas DC/DC-omvandlare. Spänningsomvandling kan utföras genom linj...

  3. 1975 Washington timber harvest.

    Science.gov (United States)

    J.D. Jr. Lloyd

    1977-01-01

    In 1975, the Washington timber harvest declined for the 2d year to 6.2 billion board feet, 10 percent below 1974, and the lowest level in 8 years. The decrease, which occurred on almost all ownerships, amounted to 561 million board feet in western Washington and 130 million board feet in eastern Washington.

  4. Adaptable DC offset correction

    Science.gov (United States)

    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.

  5. 75 FR 35611 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, and MD-10-10F...

    Science.gov (United States)

    2010-06-23

    ... Jersey Avenue, SE., Washington, DC 20590. FOR FURTHER INFORMATION CONTACT: Nenita Odesa, Aerospace... procedures found in 14 CFR 39.19. Send information to ATTN: Nenita Odesa, Aerospace Engineer, Airframe...

  6. GLASS FORMULATION TESTING TO INCREASE SULFATE INCORPORATION - Final Report VSL-04R4960-1, Rev 0, 2/28/05, Vitreous State Laboratory, The Catholic University of American, Washington, D.C.

    Energy Technology Data Exchange (ETDEWEB)

    KRUGER AA; MATLACK KS

    2012-02-07

    About 50 million gallons of high-level mixed waste is currently in storage in underground tanks at The United States Department of Energy's (DOE's) Hanford site in the State of Washington. The Hanford Tank Waste Treatment and Immobilization Plant (WTP) will provide DOE's Office of River Protection (ORP) with a means of treating this waste by vitrification for subsequent disposal. The tank waste will be separated into low- and high-activity fractions, which will then be vitrified respectively into Immobilized Low Activity Waste (ILAW) and Immobilized High Level Waste (IHLW) products. The ILAW product will be disposed of in an engineered facility on the Hanford site while the IHLW product will be directed to the national deep geological disposal facility for high-level nuclear waste. The ILAW and IHLW products must meet a variety of requirements with respect to protection of the environment before they can be accepted for disposal. The Office of River Protection is currently examining options to optimize the Low Activity Waste (LAW) facility and the LAW glass waste form. One option under evaluation is to enhance the waste processing rate of the vitrification plant currently under construction. It is likely that the capacity of the LAW vitrification plant can be increased incrementally by implementation of a variety of low-risk, high-probability changes, either separately or in combination. These changes include: (1) Operating at the higher processing rates demonstrated at the LAW Pilot Melter; (2) Increasing the glass pool surface area within the existing external melter envelope; (3) Increasing plant availability; (4) Increasing the glass waste loading; (5) Removing sulfate from the LAW stream; (6) Operating the melter at slightly higher temperature; (7) Installing the third LAW melter into the WTP plant; and (8) Other smaller impact changes. The melter tests described in this report utilized blended feed (glass formers plus waste simulant) prepared

  7. "Forback" Dc-To-Dc Converters

    Science.gov (United States)

    Lukemire, Alan T.

    1992-01-01

    Dc-to-dc power-converter circuits called "forback" resemble circuits of standard configurations called "forward", "flyback", and "Cuk". Circuit employs minor modifications to existing topologies, combines advantages, while eliminating disadvantages, of older circuits.

  8. Multiport Resonant DC-DC Converter

    OpenAIRE

    Tran, Yan-Kim; Dujic, Drazen; Barrade, Philippe

    2015-01-01

    his paper presents a multiport galvanically isolated LLC resonant DC-DC converter suitable for DC applications. A three-port structure is analyzed, with full bidirectional power flow capabilities, simple control and behavior similar to that expected from a DC transformer. Each port is equipped with half-bridge modules accompanied with tuned resonant tank, partly realized with elements of a multi- winding high frequency transformer. With some restrictions that are explained in the paper, each ...

  9. VLSI Hybrid DC-DC Regulator

    OpenAIRE

    Cosp Vilella, Jordi; Martínez García, Herminio

    2015-01-01

    Hybrid DC-DC regulators are structures that combine both a linear voltage regulator and a switching DC-DC converter. The main objective of this hybrid topology is to converge, in a single circuit topology, the best of both alternatives: a small voltage output ripple, which is a common characteristic of linear regulator circuits, and good energy efficiency, as in switching alternatives. While the linear regulator fixes the required output voltage to a fixed value with negligible steady-state r...

  10. Local Bifurcations in DC-DC Converters

    OpenAIRE

    2012-01-01

    Three local bifurcations in DC-DC converters are reviewed. They are period-doubling bifurcation, saddle-node bifurcation, and Neimark bifurcation. A general sampled-data model is employed to study the types of loss of stability of the nominal (periodic) solution and their connection with local bifurcations. More accurate prediction of instability and bifurcation than using the averaging approach is obtained. Examples of bifurcations associated with instabilities in DC-DC converters are given.

  11. High-Efficiency dc/dc Converter

    Science.gov (United States)

    Sturman, J.

    1982-01-01

    High-efficiency dc/dc converter has been developed that provides commonly used voltages of plus or minus 12 Volts from an unregulated dc source of from 14 to 40 Volts. Unique features of converter are its high efficiency at low power level and ability to provide output either larger or smaller than input voltage.

  12. Information through Cooperative Action Library Services in Metropolitan Washington. Annual Report, 1975-1976.

    Science.gov (United States)

    Gell, Marilyn, Ed.

    The Librarians Technical Committee of the Metropolitan Washington D.C. Council of Governments (COG) is responsible for developing cooperative programs among libraries in the Washington metropolitan area (including parts of Maryland and Virginia), among libraries of all types, and between libraries and other agencies. The committee facilitates use…

  13. University of Washington

    Data.gov (United States)

    Federal Laboratory Consortium — The theme of the University of Washington based Center for Child Environmental Health Risks Research (CHC) is understanding the biochemical, molecular and exposure...

  14. 城市范围绿色屋顶环境效益评价方法研究——以华盛顿市为例%Research on the Assessment Methods of Environmental Benefits for Green Roofs at Community-scale—A Case Study of Washington, D.C

    Institute of Scientific and Technical Information of China (English)

    牛皓; 周集体; Peter Adriaens

    2013-01-01

    分析华盛顿市绿色屋顶的环境效应(截留降水、节能、改善空气质量),对比绿色屋顶和传统屋顶的现值(PV),结果表明,在华盛顿市绿色规划下,40年后整个城市系统绿色屋顶的现值将比传统屋顶低30%-42%,相比单个建筑物范围又降低了3%-5%;同时绿色屋顶的投资回收期最快可以达到6-7年,相比单个建筑物范围提前1-2年.%Estimates stormwater retention, energy savings, and air quality improvement benefits for green roofs at community-scale in Washington, D.C., and incorporates these benefits into present value (PV) to make a comparative analysis with the conventional roofs. The results demonstrate that the PV of green roofs is 30%-42% less than that of conventional roofs at community-scale over 40 years, further reduces by 3%-5% comparing to that at building-scale. Lastly, the return period of investment of green roofs is expected at 6-7 years at community-scale, and further shortens 1-2 years comparing to that at building-scale.

  15. 1974 Washington timber harvest.

    Science.gov (United States)

    J.D. Jr. Lloyd

    1976-01-01

    The 1974 timber harvest of 6.88 billion board feet declined 933 million board feet (11.9 percent) below the record 1973 harvest. Decreases occurred in almost all owner groups. In western Washington the decline was 856 million board feet (13.0 percent). In eastern Washington the decline was 76 million board feet (6.3 percent).

  16. Booker T. Washington Rediscovered

    Science.gov (United States)

    Bieze, Michael Scott, Ed.; Gasman, Marybeth, Ed.

    2012-01-01

    Booker T. Washington, a founding father of African American education in the United States, has long been studied, revered, and reviled by scholars and students. Born into slavery, freed and raised in the Reconstruction South, and active in educational reform through the late nineteenth and early twentieth centuries, Washington sought to use…

  17. CMOS Integrated Capacitive DC-DC Converters

    CERN Document Server

    Van Breussegem, Tom

    2013-01-01

    This book provides a detailed analysis of all aspects of capacitive DC-DC converter design: topology selection, control loop design and noise mitigation. Readers will benefit from the authors’ systematic overview that starts from the ground up, in-depth circuit analysis and a thorough review of recently proposed techniques and design methodologies.  Not only design techniques are discussed, but also implementation in CMOS is shown, by pinpointing the technological opportunities of CMOS and demonstrating the implementation based on four state-of-the-art prototypes.  Provides a detailed analysis of all aspects of capacitive DC-DC converter design;  Analyzes the potential of this type of DC-DC converter and introduces a number of techniques to unleash their full potential; Combines system theory with practical implementation techniques; Includes unique analysis of CMOS technology for this application; Provides in-depth analysis of four fabricated prototypes.

  18. DC/DC Converter Stability Testing Study

    Science.gov (United States)

    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.

  19. Washington DC Area Computer Aided Surgery Society Monthly Meetings

    Science.gov (United States)

    2009-03-01

    experience shows that IR endoscopy can be used to define intracardiac and vascular anatomy and guide interventional procedures. 3.1.3 The Mathematics...scanning of non- sedated infants and image analysis methods that can cope with very low contrast-to-noise ratio, small brain size, variability of brain

  20. Tiger Team assessment of the Lawrence Berkeley Laboratory, Washington, DC

    Energy Technology Data Exchange (ETDEWEB)

    1991-02-01

    This report documents the results of the Department of Energy's (DOE's) Tiger Team Assessment of the Lawrence Berkeley Laboratory (LBL) conducted from January 14 through February 15, 1991. The purpose of the assessment was to provide the Secretary of Energy with the status of environment, safety, and health (ES H) programs at LBL. The Tiger Team concluded that curtailment of cessation of any operations at LBL is not warranted. However, the number and breadth of findings and concerns from this assessment reflect a serious condition at this site. In spite of its late start, LBL has recently made progress in increasing ES H awareness at all staff levels and in identifying ES H deficiencies. Corrective action plans are inadequate, however, many compensatory actions are underway. Also, LBL does not have the technical expertise or training programs nor the tracking and followup to effectively direct and control sitewide guidance and oversight by DOE of ES H activities at LBL. As a result of these deficiencies, the Tiger Team has reservations about LBL's ability to implement effective actions in a timely manner and, thereby, achieve excellence in their ES H program. 4 figs., 24 tabs.

  1. 147 between the holocaust museum in washington dc and ghana's ...

    African Journals Online (AJOL)

    HP-G61

    minutes film was commissioned from the famous Ghanaian filmmaker, Kwaw Ansah “in ... In the ensuing politics of cultural representation that rocked the castle, the ... been murdered, including about one million children, two million women.

  2. 76 FR 72021 - District of Columbia Disaster #DC-00004

    Science.gov (United States)

    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,...

  3. 77 FR 47907 - District of Columbia Disaster #DC-00005

    Science.gov (United States)

    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,...

  4. 77 FR 74907 - District of Columbia Disaster #DC-00006

    Science.gov (United States)

    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,...

  5. 76 FR 62131 - District of Columbia Disaster #DC-00003

    Science.gov (United States)

    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,...

  6. DC to DC converters: operation; Hacheurs: fonctionnement

    Energy Technology Data Exchange (ETDEWEB)

    Bernot, F. [Ecole d' Ingenieurs de Tours, 37 (France)

    2002-05-01

    This article deals with pulse width modulation (PWM) and pulse position modulation (PPM) DC to DC converters. A tri-phase PWM converter is made of 6 simple DC/DC converters grouped together into 3 reversible converters of the same type: 1 - single-quadrant voltage lowering converters (hydraulic analogy, study with ideal elements, full scheme with input and output filters); 2 - single-quadrant voltage raising converters (hydraulic analogy, operation); 3 - two quadrants reversible converters (structure construction, quadrants of operation, reversible converter connected to a DC motor); 4 - four-quadrants reversible converters; 5 - other converters structure (current converters and converters with intermediate storage, asymmetrical converters, converters with capacitive storage, insulated converters, resonating converters, status); 6 - conclusion. (J.S.)

  7. Washington County Crash Data

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Contains locations and information about every crash incident reported to the police in Washington County from 2011 to 2015. Fields include injury severity,...

  8. A resonant dc-dc power converter assembly

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a resonant DC-DC power converter assembly comprising a first resonant DC-DC power converter and a second resonant DC-DC power converter having identical circuit topologies. A first inductor of the first resonant DC-DC power converter and a second inductor...... of the second resonant DC-DC power converter are configured for magnetically coupling the first and second resonant DC-DC power converters to each other to forcing substantially 180 degrees phase shift, or forcing substantially 0 degree phase shift, between corresponding resonant voltage waveforms of the first...... and second resonant DC-DC power converters. The first and second inductors are corresponding components of the first and second resonant DC-DC power converters....

  9. Charge pump DC-DC converter comprising solid state batteries

    NARCIS (Netherlands)

    Reefman, D.; Roozeboom, F.; Notten, P.H.L.; Klootwijk, J.H.

    2013-01-01

    An electronic device is provided which comprises a DC-DC converter. The DC-DC converter comprises at least one solid-state rechargeable battery (B1, B2) for storing energy for the DC-DC conversion and an output capacitor (C2).

  10. DC source assemblies

    Science.gov (United States)

    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.

  11. Radiation effects on DC-DC Converters

    Science.gov (United States)

    Zhang, Dexin; Attia, John O.; Kankam, Mark D. (Technical Monitor)

    2000-01-01

    DC-DC switching converters are circuits that can be used to convert a DC voltage of one value to another by switching action. They are increasing being used in space systems. Most of the popular DC-DC switching converters utilize power MOSFETs. However power MOSFETs, when subjected to radiation, are susceptible to degradation of device characteristics or catastrophic failure. This work focuses on the effects of total ionizing dose on converter performance. Four fundamental switching converters (buck converter, buck-boost converter, cuk converter, and flyback converter) were built using Harris IRF250 power MOSFETs. These converters were designed for converting an input of 60 volts to an output of about 12 volts with a switching frequency of 100 kHz. The four converters were irradiated with a Co-60 gamma source at dose rate of 217 rad/min. The performances of the four converters were examined during the exposure to the radiation. The experimental results show that the output voltage of the converters increases as total dose increases. However, the increases of the output voltage were different for the four different converters, with the buck converter and cuk converter the highest and the flyback converter the lowest. We observed significant increases in output voltage for cuk converter at a total dose of 24 krad (si).

  12. 75 FR 61989 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-8-31, DC-8-32, DC-8-33, DC-8-41...

    Science.gov (United States)

    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:......

  13. 75 FR 36298 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-8-31, DC-8-32, DC-8-33, DC-8-41...

    Science.gov (United States)

    2010-06-25

    ... 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-8-61 Series Airplanes; Model DC-8-70 Series Airplanes; and Model DC-8-70F Series Airplanes AGENCY:......

  14. A DC Transformer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — During the period of this project three different possible DC transformer concepts were proposed, theoretically modeled, and then experimentally tested with the...

  15. The Public Benefit of Energy Efficiency to the State of Washington

    Science.gov (United States)

    2002-01-01

    Washington State Office of Trade and Economic Development NCLC National Consumer Law Center NERC North American Electric Reliability Council NOX Nitrogen...Analysis of low-income benefits in determining cost-effectiveness of energy efficiency programs. Washington, D.C. National Consumer Law Center. Jorgenson...A.H. 1990. How Does Public Infrastructure Affect Regional Economic Performance? New England Economic Review 0(0): 11-32. National Consumer Law Center

  16. Description and Status of the DC Lightning Mapping Array

    Science.gov (United States)

    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.

  17. Radiation Effects on DC-DC Converters

    Science.gov (United States)

    Zhang, De-Xin; AbdulMazid, M. D.; Attia, John O.; Kankam, Mark D. (Technical Monitor)

    2001-01-01

    In this work, several DC-DC converters were designed and built. The converters are Buck Buck-Boost, Cuk, Flyback, and full-bridge zero-voltage switched. The total ionizing dose radiation and single event effects on the converters were investigated. The experimental results for the TID effects tests show that the voltages of the Buck Buck-Boost, Cuk, and Flyback converters increase as total dose increased when using power MOSFET IRF250 as a switching transistor. The change in output voltage with total dose is highest for the Buck converter and the lowest for Flyback converter. The trend of increase in output voltages with total dose in the present work agrees with those of the literature. The trends of the experimental results also agree with those obtained from PSPICE simulation. For the full-bridge zero-voltage switch converter, it was observed that the dc-dc converter with IRF250 power MOSFET did not show a significant change of output voltage with total dose. In addition, for the dc-dc converter with FSF254R4 radiation-hardened power MOSFET, the output voltage did not change significantly with total dose. The experimental results were confirmed by PSPICE simulation that showed that FB-ZVS converter with IRF250 power MOSFET's was not affected with the increase in total ionizing dose. Single Event Effects (SEE) radiation tests were performed on FB-ZVS converters. It was observed that the FB-ZVS converter with the IRF250 power MOSFET, when the device was irradiated with Krypton ion with ion-energy of 150 MeV and LET of 41.3 MeV-square cm/mg, the output voltage increased with the increase in fluence. However, for Krypton with ion-energy of 600 MeV and LET of 33.65 MeV-square cm/mg, and two out of four transistors of the converter were permanently damaged. The dc-dc converter with FSF254R4 radiation hardened power MOSFET's did not show significant change at the output voltage with fluence while being irradiated by Krypton with ion energy of 1.20 GeV and LET of 25

  18. 75 FR 38943 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-30, DC...

    Science.gov (United States)

    2010-07-07

    ... Corporation Model DC- 10-10, DC-10-10F, DC-10-30, DC-10-30F (KDC-10), DC-10-40, and DC-10-40F Airplanes AGENCY... propose to adopt a new airworthiness directive (AD) for certain Model DC-10-10, DC-10-10F, DC-10-30, DC-10-30F (KDC-10), DC-10- 40, and DC-10-40F airplanes. This proposed AD would require......

  19. Radiation-Tolerant DC-DC Converters

    Science.gov (United States)

    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).

  20. Bidirectional dc-to-dc Power Converter

    Science.gov (United States)

    Griesbach, C. R.

    1986-01-01

    Solid-state, series-resonant converter uses high-voltage thyristors. Converter used either to convert high-voltage, low-current dc power to lowvoltage, high current power or reverse. Taking advantage of newly-available high-voltage thyristors to provide better reliability and efficiency than traditional converters that use vacuum tubes as power switches. New converter essentially maintenance free and provides greatly increased mean time between failures. Attractive in industrial applications whether or not bidirectional capability is required.

  1. Forback DC-to-DC converter

    Science.gov (United States)

    Lukemire, Alan T.

    1995-05-01

    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. Forback DC-to-DC converter

    Science.gov (United States)

    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.

  3. Intelligent dc-dc Converter Technology Developed and Tested

    Science.gov (United States)

    Button, Robert M.

    2001-01-01

    The NASA Glenn Research Center and the Cleveland State University have developed a digitally controlled dc-dc converter to research the benefits of flexible, digital control on power electronics and systems. Initial research and testing has shown that conventional dc-dc converters can benefit from improved performance by using digital-signal processors and nonlinear control algorithms.

  4. Alliance Reborn: An Atlantic Compact for the 21st Century. The Washington NATO Project

    Science.gov (United States)

    2009-02-01

    drugs and disease. We characterize these phenomena as "global," but their impact is local. They are unprecedented in their range, scope and speed...in Christina Balis and Simon Serfaty, eds., Visions of America and Europe: September 11, Iraq, and Transatlantic Relations (Washington, DC: CSIS

  5. 75 FR 20790 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-15, DC...

    Science.gov (United States)

    2010-04-21

    ... 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... (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, DC-10-40F, MD-10-10F, MD-10-30F, MD-11, and MD-11F airplanes. This proposed......

  6. 75 FR 68246 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-15, DC...

    Science.gov (United States)

    2010-11-05

    ... 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... to supersede an existing airworthiness directive (AD) that applies to all 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, MD-10-......

  7. Three-port DC-DC converter with new integrated transformer for DC Distribution Systems

    DEFF Research Database (Denmark)

    Ouyang, Ziwei; Andersen, Michael A. E.

    2014-01-01

    A new integrated transformer for three-port dc-dc converter is proposed to overcome the power coupling effect existed in some known multiple inputs dc-dc converters. Orthogonal primary windings arrangement and in series connection of diagonal secondary Windings enables a fully power decoupling...

  8. Washington State Biofuels Industry Development

    Energy Technology Data Exchange (ETDEWEB)

    Gustafson, Richard [Univ. of Washington, Seattle, WA (United States)

    2017-04-09

    The funding from this research grant enabled us to design, renovate, and equip laboratories to support University of Washington biofuels research program. The research that is being done with the equipment from this grant will facilitate the establishment of a biofuels industry in the Pacific Northwest and enable the University of Washington to launch a substantial biofuels and bio-based product research program.

  9. Research borehole drilling activity for boreholes DH-18, DH-19, DC-12, DC-13, DC-14, DC-15, and deepening of existing borehole DC-7

    Energy Technology Data Exchange (ETDEWEB)

    1979-09-01

    This report is an environmental evaluation of the impacts of proposed borehole drilling activities at the Hanford Site, northwest of Richland, Washington. The proposed action is to drill six research boreholes ranging in depth from 137 to 1372 meters (m) (250 to 4500 +- feet (ft)). In addition, an existing borehole (DC-7) will be extended from 1249 to 1524 m (4099 to 5000 +- ft). The purpose of the US Department of Energy's (DOE) borehole drilling activities is to collect data on in situ rock formations that are considered potentialy suitable for nuclear waste repositories. The technical program efforts necessary to identify and qualify specific underground waste facility sites in candidate rock formations include geologic and hydrologic studies (seismicity and tectonics, rock structure and stratigraphy, lithology, etc.). Borehole drilling is an integral part of the geological studies and is essential to a thorough understanding of potentially suitable geologic formations. The purpose of the proposed drilling activities is to obtain data for evaluating Columbia River basalts that are being evaluated by the National Waste Terminal Storage (NWTS) Program to determine their suitability potential for nuclear waste repositories. Unavoidable impact to the environment is limited primarily to the clearing of land needed for access and drilling operations. Considerations exercised during site preparation, drilling, and subsequent site restoration will limit modification of the natural environment to the minimum required for accomplishment of test objectives.

  10. Overview of Multi-DC-Bus Solutions for DC Microgrids

    DEFF Research Database (Denmark)

    Ricchiuto, D.; Mastromauro, R.A.; Liserre, Marco;

    2013-01-01

    DC Microgrids have recently received a lot of attention in the last years due to high penetration of renewable energy sources as well as distributed energy storage systems. In the future DC microgrids could be preferable respect to AC microgrids in terms of redundancy since multi-DC-Bus solutions...... could provide a continuative power supply to the loads. An overview of Multi-DC-Bus solutions is presented in this paper. The performances are compared on the basis of possible DC microgrid configurations, redundancy, different DC voltage levels....

  11. 75 FR 60602 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-15, DC...

    Science.gov (United States)

    2010-10-01

    ... 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,......

  12. 75 FR 23571 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-15, DC...

    Science.gov (United States)

    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,......

  13. 5 CFR 591.216 - How does OPM combine survey data for the DC area and for COLA areas with multiple survey areas?

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false How does OPM combine survey data for the DC area and for COLA areas with multiple survey areas? 591.216 Section 591.216 Administrative... combine survey data for the DC area and for COLA areas with multiple survey areas? (a) Washington,...

  14. DC-DC powering for the CMS pixel upgrade

    Science.gov (United States)

    Feld, Lutz; Fleck, Martin; Friedrichs, Marcel; Hensch, Richard; Karpinski, Waclaw; Klein, Katja; Rittich, David; Sammet, Jan; Wlochal, Michael

    2013-12-01

    The CMS experiment plans to replace its silicon pixel detector with a new one with improved rate capability and an additional detection layer at the end of 2016. In order to cope with the increased number of detector modules the new pixel detector will be powered via DC-DC converters close to the sensitive detector volume. This paper reviews the DC-DC powering scheme and reports on the ongoing R&D program to develop converters for the pixel upgrade. Design choices are discussed and results from the electrical and thermal characterisation of converter prototypes are shown. An emphasis is put on system tests with up to 24 converters. The performance of pixel modules powered by DC-DC converters is compared to conventional powering. The integration of the DC-DC powering scheme into the pixel detector is described and system design issues are reviewed.

  15. DC-DC Powering for the CMS Pixel Upgrade

    CERN Document Server

    Feld, Lutz Werner; Marcel Friedrichs; Richard Hensch; Karpinski, Waclaw; Klein, Katja; Rittich, David Michael; Sammet, Jan Domenik; Wlochal, Michael

    2013-01-01

    The CMS experiment plans to replace its silicon pixel detector with a new one with improved rate capability and an additional detection layer at the end of 2016. In order to cope with the increased number of detector modules the new pixel detector will be powered via DC-DC converters close to the sensitive detector volume. This paper reviews the DC-DC powering scheme and reports on the ongoing R and D program to develop converters for the pixel upgrade. Design choices are discussed and results from the electrical and thermal characterisation of converter prototypes are shown. An emphasis is put on system tests with up to24 converters. The performance of pixel modules powered by DC-DC converters is compared to conventional powering. The integration of the DC-DC powering scheme into the pixel detector is described and system design issues are reviewed.

  16. Chernobyl radioactivity in surface air over Washington D. C

    Energy Technology Data Exchange (ETDEWEB)

    Faller, S.H.; Kuroda, P.K. (Environmental Protection Agency, Las Vegas, NV (USA). Environmental Monitoring Systems Lab.); Krask, D.J. (District of Columbia Dept. of Consumer, and Regulatory Affairs, Washington, DC (USA). Air Monitoring Section)

    1991-01-01

    Concentrations of Chernobyl-derived radionuclides in airborne particulate matter over Washington D.C. have been determined by gamma-ray analysis of air filter samples collected during the months of May, June, and July 1986. The results indicate that long-lived nuclides were present in levels comparable to those measured previously at other eastern locations. Extensive washout of radioactivity occurred apparently as a result of heavy rainfall on May 20, and was followed by the arrival of airborne debris with elevated {sup 103}Ru/{sup 137}Cs and {sup 106}Ru/{sup 137}Cs activity ratios. (orig.).

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

    Science.gov (United States)

    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.

  18. 75 FR 6160 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-15, DC...

    Science.gov (United States)

    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-10-40, DC-10-40F, MD-10-10F, MD-10-30F, MD-11, and MD-11F Airplanes AGENCY: Federal Aviation... airworthiness directive (AD) for certain Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC- 10A...

  19. 12 CFR 4.4 - Washington office.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Washington office. 4.4 Section 4.4 Banks and... EXAMINERS Organization and Functions § 4.4 Washington office. The Washington office of the OCC is the main office and headquarters of the OCC. The Washington office directs OCC policy, oversees OCC...

  20. Control of improved full-bridge three-level DC/DC converter for wind turbines in a DC grid

    DEFF Research Database (Denmark)

    Deng, Fujin; Chen, Zhe

    2013-01-01

    transformer in the IFBTL dc/dc converter. A modulation strategy, including two operation modes, is proposed for the IFBTL dc/dc converter. Then, a voltage balancing control strategy is proposed for the IFBTL dc/dc converter. Furthermore, the control of the wind turbine based on the IFBTL dc/dc converter......This paper presents an improved full-bridge three-level (IFBTL) dc/dc converter for a wind turbine in a dc grid by inserting a passive filter into the dc/dc converter to improve the performance of the converter. The passive filter can effectively reduce the voltage stress of the medium frequency...... in a dc-grid system is presented. Finally, a small-scale IFBTL dc/dc converter prototype was built and tested in the laboratory, and the results verify the theoretical analysis....

  1. 75 FR 47242 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-14, DC-9-15, and DC-9-15F...

    Science.gov (United States)

    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......

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

    Science.gov (United States)

    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

  3. A new optimum topology switching dc-to-dc converter

    Science.gov (United States)

    Cuk, S.; Middlebrook, R. D.

    1977-01-01

    A novel switching dc-to-dc converter is presented, which has the same general conversion property (increase or decrease of the input dc voltage) as does the conventional buck-boost converter, and which offers through its new optimum topology higher efficiency, lower output voltage ripple, reduced EMI, smaller size and weight, and excellent dynamic response. One of its most significant advantages is that both input and output current are not pulsating but are continuous (essentially dc with small superimposed switching current ripple), thus resulting in a close approximation to the ideal physically nonrealizable dc-to-dc transformer. The converter retains the simplest possible structure with the minimum number of components which, when interconnected in its optimum topology, yield the maximum performance.

  4. Conception de convertisseurs DC/DC à base de MEMS

    OpenAIRE

    Ghandour, Sahar

    2011-01-01

    Current trends towards miniaturization of electronic circuits had led to the advent of System onChip containing different types of circuits indented to perform different functions. These sub-systemsrequire different supply voltages that are delivered from the SoC supply voltage using several DC/DCconverters. Currently, most of the electronic circuits of portable applications use conventional SMPS(switch mode power supply) DC/DC converters containing an inductor element to stock temporally the...

  5. A Novel FPSM Controller for DC-DC Switching Converters

    Institute of Scientific and Technical Information of China (English)

    Yong Feng; Shun-Ping Wang; Ping Luo; Quan-Ming Niu; Zhao-Ji Li

    2007-01-01

    This paper presents a novel fuzzy pulse skip modulation (FPSM) controller for switching direct current to direct current (DC-DC) converters based on fuzzy ratiocination modeling approach. Owing to the optimal consideration during the design and the nonlinear characteristics of the controller, improved dynamic responses of the FPSM controller can be achieved over conventional controllers. Compared with conventional proportion integral derivative (PID) control, FPSM control has 60% lower overshoot and 10% lower setting time under the same input voltage and output load change. The presented approach is general and can be applied to other types of DC-DC converters.

  6. High performance dc-dc conversion with voltage multipliers

    Science.gov (United States)

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

    1974-01-01

    The voltage multipliers using capacitors and diodes first developed by Cockcroft and Walton in 1932 were reexamined in terms of state of the art fast switching transistors and diodes, and high energy density capacitors. Because of component improvements, the voltage multiplier, used without a transformer, now appears superior in weight to systems now in use for dc-dc conversion. An experimental 100-watt 1000-volt dc-dc converter operating at 100 kHz was built, with a component weight of about 1 kg/kW. Calculated and measured values of output voltage and efficiency agreed within experimental error.

  7. Improved DC Gun Insulator

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. 40 CFR 81.348 - Washington.

    Science.gov (United States)

    2010-07-01

    ... Washington Intrastate Unclassifiable/Attainment Clallam County Grays Harbor County Island County Jefferson... Olympic-Northwest Washington Intrastate: Clallam County Unclassifiable/Attainment. Grays Harbor County.../Attainment Clallam County Grays Harbor County Island County......

  9. Libraries in Washington: MedlinePlus

    Science.gov (United States)

    ... this page: https://medlineplus.gov/libraries/washington.html Libraries in Washington To use the sharing features on ... enable JavaScript. Bellevue Overlake Hospital Medical Center Medical Library 1035 116th Avenue NE Bellevue, WA 98004 425- ...

  10. Hysteretic Current Controlled Zvs Dc/Dc Converter For Automobile

    DEFF Research Database (Denmark)

    Cernat, M.; Scortarul, P.; Tanase, A.

    2007-01-01

    A novel bi-directional dc-dc converter with ZVS and interleaving for dual voltage systems in automobiles is presented. A variable frequency extended band hysteretic current control method is proposed. In comparison with classical fixed frequency current control PWM, the reverse polarity peak curr...

  11. Very High Frequency Half Bridge DC/DC Converter

    DEFF Research Database (Denmark)

    Madsen, Mickey Pierre; Knott, Arnold; Andersen, Michael A. E.

    2014-01-01

    This paper presents the first, off chip, class DE (resonant half bridge) converter working in the Very High Frequency (VHF) range. The benefits of using half bridge circuits both in the inverter and rectifier part of a VHF resonant dc/dc converter are analyzed and design equations for all...

  12. A Plasma-Based DC-DC Electrical Transformer

    Science.gov (United States)

    Nebel, Richard; Finn, John

    2013-10-01

    Previous work has indicated that it may be possible to make DC-DC electrical transformers using plasmas. The mechanism is an MHD electromagnetic relaxation process induced by helical electrodes. This process is now being tested on the Bismark device at Tibbar Technologies.

  13. A Current-Fed Isolated Bidirectional DC-DC Converter

    DEFF Research Database (Denmark)

    Sun, Xiaofeng; Wu, Xiaoying; Shen, Yanfeng;

    2017-01-01

    This paper proposes a current-fed isolated bidirectional DC-DC converter (CF-IBDC) which has the advantages of wide input voltage range, low input current ripple, low conduction losses, and soft switching over the full operating range. Compared with conventional CF-IBDCs, the voltage spikes of th...

  14. SCM Handbooks for dc-to-dc Converters

    Science.gov (United States)

    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.

  15. Efficient Design in a DC to DC Converter Unit

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  17. An organic integrated capacitive DC-DC up-converter

    NARCIS (Netherlands)

    Marien, H.; Steyaert, M.; Steudel, S.; Vicca, P.; Smout, S.; Gelinck, G.H.; Heremans, P.L.

    2010-01-01

    In this paper a fully integrated organic DC-DC upconverter is presented in a pentacene p-type only technology. This 3-stage Dickson converter reaches a voltage conversion factor of 3 for a purely capacitive load and 2.5 for a 10 μA load current. The maximal output voltage goes up to 75 V and the Dic

  18. Sheppard-Taylor Isolated High Boost DC-DC Converter

    DEFF Research Database (Denmark)

    Chub, Andrii; Siwakoti, Yam Prasad; Vinnikov, Dmitri

    2017-01-01

    This paper presents a new galvanically isolated step-up dc-dc converter intended for low-power but high step-up applications. The proposed converter is capable of regulating output voltage within a wide range of the input voltage or load variations. In contrast to competitors, the converter can b...

  19. General Plan Environmental Assessment for Joint Base Andrews-Naval Air Facility, Washington, Maryland

    Science.gov (United States)

    2011-04-01

    housing/office space above, creating a pleasant and more walkable downtown atmosphere. The 33-plus-foot-wide area along Main Street provides walkways...1.1 and 1.2 and actions to promote walkability , reduce vehicle miles traveled (VMT), promote sustainable practices, and account for the...approximately five miles from Washington, D.C., is part of an inner suburb of a large city . The communities of Camp Springs, Morningside, Woodyard

  20. Basic Research at the University of Washington to Counter Improvised Explosive Devices

    Science.gov (United States)

    2011-01-31

    Explosives Detection Techniques, 148 pp, National Academy Press, Washington D.C. Fidric, B. G., et al. (2003), Bananas , explosives and the future of...ray scattering (NRIXS). The inelastic scattering from the core shell electrons of low-Z elements such as nitrogen can be readily detected by...Elam, J. O. Cross, and K. P. Nagle, “Deconvolving Instrumental and Intrinsic Broadening in Core- shell X-ray Spectroscopies,” Physical Review B 75

  1. Teaching the March on Washington

    Science.gov (United States)

    Jones, William P.; Euchner, Charles; Hill, Norman; Hill, Velma Murphy

    2013-01-01

    One of the most historical events in American history, the non-violent protest "March on Washington," August 28, 1963, is detailed in an article of remembrance by William P. Jones. His article is crowned by highlights from the "I Have a Dream" speech by Dr. Martin Luther King, Jr., but also highlights the lessor known role…

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

    Science.gov (United States)

    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

    Science.gov (United States)

    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. DC Microgrids—Part II

    DEFF Research Database (Denmark)

    Dragicevic, Tomislav; Lu, Xiaonan; Quintero, Juan Carlos Vasquez

    2016-01-01

    distribution applications such as traction, telecom, vehicular and distributed power systems can be classified under DC MG framework and ongoing development and expansion of the field is largely influenced by concepts used over there. This paper aims firstly to shed light on the practical design aspects of DC...

  5. Modular Power System Configured with Standard Product Hybrid DC-DC Converters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — VPT proposes an innovative concept whereby complex, multiple-output, DC-DC converter systems can be configured through use of only 2 standard product hybrid DC-DC...

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

    Science.gov (United States)

    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.

  7. SMALL-SCALE MELTER TESTING WITH LAW SIMULANTS TO ASSESS THE IMPACT OF HIGHER TEMPERATURE MELTER OPERATIONS - Final Report, VSL-04R49801-1, Rev. 0, 2/13/03, Vitreous State Laboratory, The Catholic University of America, Washington, D.C.

    Energy Technology Data Exchange (ETDEWEB)

    KRUGER AA; MATLACK KS

    2012-02-07

    About 50 million gallons of high-level mixed waste is currently in storage in underground tanks at The United States Department of Energy's (DOE's) Hanford site in the State of Washington. The Hanford Tank Waste Treatment and Immobilization Plant (WTP) will provide DOE's Office of River Protection (ORP) with a means of treating this waste by vitrification for subsequent disposal. The tank waste will be separated into low- and high-activity fractions, which will then be vitrified respectively into Immobilized Low Activity Waste (ILAW) and Immobilized High Level Waste (IHLW) products. The ILAW product will be disposed of in an engineered facility on the Hanford site while the IHL W product will be directed to the national deep geological disposal facility for high-level nuclear waste. The ILAW and IHLW products must meet a variety of requirements with respect to protection of the environment before they can be accepted for disposal. The Office of River Protection is currently examining options to optimize the Low Activity Waste (LAW) facility and the LAW glass waste form. One option under evaluation is to enhance the waste processing rate of the vitrification plant currently under construction. It is likely that the capacity of the LAW vitrification plant can be increased incrementally by implementation of a variety of low-risk, high-probability changes, either separately or in combination. These changes include: (1) Operating at the higher processing rates demonstrated at the LAW Pilot Melter; (2) Increasing the glass pool surface area within the existing external melter envelope; (3) Increasing plant availability; (4) Increasing the glass waste loading; (5) Removing sulfate from the LAW stream; (6) Operating the melter at slightly higher temperature; (7) Installing the third LAW melter into the WTP plant; and (8) Other smaller impact changes. The tests describes in this report utilized blended feed (glass formers plus waste simulant) prepared by

  8. GaN Microwave DC-DC Converters

    Science.gov (United States)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. Transformerless DC-DC Converter Using Cockcroft-Walton Voltage Multiplier to Obtain High DC Voltage

    Directory of Open Access Journals (Sweden)

    Meghana G Naik,

    2014-11-01

    Full Text Available In the present scenario the use of transformer for high voltages in converter circuit reduces the overall operating efficiency due to leakage inductance and use of transformer also increases the operational cost. . Therefore the proposed system is implemented with transformer less DC-DC converter so as to obtain high DC voltage with the use of nine stage Cockcroft-Walton (CW voltage multiplier. The proposed converter operates in CCM (continuous conduction mode, so that the converter switch stress, the switching losses are reduced. The DC voltage at the input of the proposed model is low and is boosted up by boost inductor (Ls in DC-DC converter stage and performs inverter operation. The number of stages in CW-voltage multiplier circuit is applied with low input pulsating DC (AC Voltage voltage where it is getting converted to high DC output voltage. The proposed converter switches operates at two independent frequencies, modulating (fsm andalternating (fsc frequency. The fsm operates at higher frequency of the output while the fsc operates at lower frequency of the desired output voltage ripple and the output ripples can be adjusted by the switch Sc1 and Sc2. The regulation of the output voltage is achieved by controlling the Duty ratio.The simulation is carried over by the MATLABSIMULINK.

  11. Tsunami Preparedness in Washington (video)

    Science.gov (United States)

    Loeffler, Kurt; Gesell, Justine

    2010-01-01

    Tsunamis are a constant threat to the coasts of our world. Although tsunamis are infrequent along the West coast of the United States, it is possible and necessary to prepare for potential tsunami hazards to minimize loss of life and property. Community awareness programs are important, as they strive to create an informed society by providing education and training. This video about tsunami preparedness in Washington distinguishes between a local tsunami and a distant event and focus on the specific needs of this region. It offers guidelines for correct tsunami response and community preparedness from local emergency managers, first-responders, and leading experts on tsunami hazards and warnings, who have been working on ways of making the tsunami affected regions safer for the people and communities on a long-term basis. This video was produced by the US Geological Survey (USGS) in cooperation with Washington Emergency Management Division (EMD) and with funding by the National Tsunami Hazard Mitigation Program.

  12. Aquatic habitat guidelines in Washington

    OpenAIRE

    2001-01-01

    Originating as the Stream Corridor Management Workgroup early in 1997, the first major milepost in seeking a statewide-integrated approach to working in and near streams, lakes, and wetlands was a Stream Corridor Management Symposium, held in Ellensburg in June 1998. Major partners in this effort were the Washington Departments of Transportation, Ecology, and Fish and Wildlife. The three-day symposium was structured with three areas of emphasis: • The first section presented the fund...

  13. An Efficient DC- DC Converter with Bidirectional Power Flow

    Directory of Open Access Journals (Sweden)

    N.RAJARAJESWARI

    2008-07-01

    Full Text Available This paper introduces a Bi-directional DC-DC converter with adaptive fuzzy logic controller. Bidirectional power flow is obtained by same power components and provides a simple, efficient, and galvanically isolated converter. In the presence of DC mains the converter operates as buck converter and charges the battery. When the DC mains fails, the converter operates as boost converter and the down stream converter is fed by the battery. The power switches are controlled by Pulse Width Modulation technique and the pulses are generated by the application of fuzzy logic with an adoption algorithm. The proposed converter is simulated using MATLAB and laboratory prototype was developed to validate the simulation results.

  14. Fuzzy Control of DC-DC Converters with Input Constraint

    Directory of Open Access Journals (Sweden)

    D. Saifia

    2012-01-01

    Full Text Available This paper proposes a method for designing fuzzy control of DC-DC converters under actuator saturation. Because linear control design methods do not take into account the nonlinearity of the system, a T-S fuzzy model and a controller design approach is used. The designed control not only handles the external disturbance but also the saturation of duty cycle. The input constraint is first transformed into a symmetric saturation which is represented by a polytopic model. Stabilization conditions for the state feedback system of DC-DC converters under actuator saturation are established using the Lyapunov approach. The proposed method has been compared and verified with a simulation example.

  15. General-purpose fuzzy controller for dc-dc converters

    Energy Technology Data Exchange (ETDEWEB)

    Mattavelli, P.; Rossetto, L.; Spiazzi, G.; Tenti, P. [Univ. of Padova (Italy)

    1997-01-01

    In this paper, a general-purpose fuzzy controller for dc-dc converters is investigated. Based on a qualitative description of the system to be controlled, fuzzy controllers are capable of good performances, even for those systems where linear control techniques fail, e.g., when a mathematical description is not available or is in the presence of wide parameter variations. The presented approach is general and can be applied to any dc-dc converter topologies. Controller implementation is relatively simple and can guarantee a small-signal response as fast and stable as other standard regulators and an improved large-signal response. Simulation results of Buck-Boost and Sepic converters show control potentialities.

  16. Step-Up DC-DC Power Converter

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a step-up DC-DC power converter which comprises a primary side circuit and a secondary side circuit coupled through a galvanic isolation barrier. The primary side circuit comprises a positive and a negative input terminal for receipt of an input voltage and an input...... being charged from the input voltage and discharged to the output capacitor through the galvanic isolation barrier in accordance with a switch control signal to produce the converter output voltage. The step-up DC-DC power converter comprises an electrical short-circuit connection across the galvanic...... capacitor coupled between the positive and negative input terminals and the secondary side circuit comprises an output capacitor chargeable to a converter output voltage between a first positive electrode and a second negative electrode. A switched energy storage network is configured for alternatingly...

  17. A Novel High Gain DC-DC Step up Converter

    Directory of Open Access Journals (Sweden)

    M. Al Mamun

    2016-07-01

    Full Text Available High gain dc-dc converters are widely used to maximize the energy harvest for renewable energy systems, for example, photovoltaic systems and fuel cell. Conventional boost converters usually operates at extreme duty cycle to obtain high voltage gain. Operation at extreme duty cycle leads to reverse recovery problem at the switches, high conduction loss, electromagnetic interference etc. This paper proposes a very high gain dc-dc step up converter operating at very low duty cycle (i.e. duty cycle <0.5. The additional advantage of the proposed converter is that a single control signal is used for the switches which reduces the operation complexity. The steady-state theoretical analysis described in this paper is finally verified by simulation results

  18. Decentralized Interleaving of Paralleled Dc-Dc Buck Converters: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Brian B [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rodriguez, Miguel [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-01

    We present a decentralized control strategy that yields switch interleaving among parallel connected dc-dc buck converters without communication. The proposed method is based on the digital implementation of the dynamics of a nonlinear oscillator circuit as the controller. Each controller is fully decentralized, i.e., it only requires the locally measured output current to synthesize the pulse width modulation (PWM) carrier waveform. By virtue of the intrinsic electrical coupling between converters, the nonlinear oscillator-based controllers converge to an interleaved state with uniform phase-spacing across PWM carriers. To the knowledge of the authors, this work represents the first fully decentralized strategy for switch interleaving of paralleled dc-dc buck converters.

  19. Active pre-filters for dc/dc Boost regulators

    Directory of Open Access Journals (Sweden)

    Carlos Andrés Ramos-Paja

    2014-07-01

    Full Text Available This paper proposes an active pre-filter to mitigate the current harmonics generated by classical dc/dc Boost regulators, which generate current ripples proportional to the duty cycle. Therefore, high output voltage conditions, i.e., high voltage conversion ratios, produce high current harmonics that must be filtered to avoid damage or source losses. Traditionally, these current components are filtered using electrolytic capacitors, which introduce reliability problems because of their high failure rate. The solution introduced in this paper instead uses a dc/dc converter based on the parallel connection of the Boost canonical cells to filter the current ripples generated by the Boost regulator, improving the system reliability. This solution provides the additional benefits of improving the overall efficiency and the voltage conversion ratio. Finally, the solution is validated with simulations and experimental results.

  20. A Feed-Forward Control Realizing Fast Response for Three-Branch Interleaved DC-DC Converter in DC Microgrid

    DEFF Research Database (Denmark)

    Wang, Haojie; Han, Minxiao; Yan, Wenli

    2016-01-01

    It is a common practice for storage batteries to be connected to DC microgrid buses through DC-DC converters for voltage support on islanded operation mode. A feed-forward control based dual-loop constant voltage PI control for three-branch interleaved DC-DC converters (TIDC) is proposed for stor......It is a common practice for storage batteries to be connected to DC microgrid buses through DC-DC converters for voltage support on islanded operation mode. A feed-forward control based dual-loop constant voltage PI control for three-branch interleaved DC-DC converters (TIDC) is proposed...... for storage batteries in DC microgrids. The working principle of TIDC is analyzed, and the factors influencing the response rate based on the dual-loop constant voltage control for TIDC are discussed, and then the method of feed-forward control for TIDC is studied to improve the response rate for load...

  1. DC-SIGN/DC-SIGNR基因多态性与病原微生物感染%Polymorphisms of DC-SIGN/DC-SIGNR and pathogen infection

    Institute of Scientific and Technical Information of China (English)

    许利军; 潘晨; 李勤光

    2010-01-01

    DC-SIGN和DC-SIGNR是两种表达于DC表面的蛋白,被认为是许多病原微生物的黏附受体,参与很多病原微生物的感染.DC-SIGN和DC-SIGNR(DC-SIGN/DC-SIGNR)的多态性或许影响病原微生物的感染过程和结果.此文对DC-SIGN/DC-SIGNR的结构功能以及与HIV、HCV感染、肺结核、登革热的关系进行了综述.%DC-SIGN and DC-SIGNR are two surface proteins on dendritic cells with complex stmction, and are regarded as attachment receptors of many pathogens, DC-SIGN/DC-SIGNR participate in pathogen infection.Polymorphisms of DC-SIGN/DC-SIGNR probably influence the procedure and outcome of pathogen infection. In this article, the structure and function of DC-SIGN/DC-SIGNR are discussed as well as the relation between the DC-SIGN/DC-SIGNR and pathogens such as HIV, HCV infection, pulmonary tuberculosis, dengue fever.

  2. DC injection into low voltage AC networks

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    This report summarises the results of a study investigating the impact of levels of injected DC current injections on a low voltage AC distribution network systems in order to recommend acceptable limits of DC from microgeneration. Relevant literature is reviewed, and the impact of DC levels in distribution transformers, transformer modelling, and instrumental transformers are discussed. The impact of DC in residual current devices (RCD) and in domestic electricity watt hour meters is examined along with DC enhanced corrosion, corrosion failure, and the measurement of DC current injection. Sources of DC injection outlined include DC from computer power supplies, network faults, geomagnetic phenomena, lighting circuits/dimmers, and embedded generators.

  3. DC-Compensated Current Transformer.

    Science.gov (United States)

    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.

  4. Modified Multiport Dc-Dc Converter Topology For Smart Grid

    Directory of Open Access Journals (Sweden)

    Dhamodharan Shanmugam

    2013-10-01

    Full Text Available The development of a Solid State Transformer (SST that incorporates a DC-DC multiport converter to integrate both photovoltaic (PV power generation and battery energy storage is presented in this dissertation. The DC-DC stage is based on a quad active-bridge (QAB converter which not only provides isolation for the load, but also for the PV and storage. The AC-DC stage is implemented with a pulse-widthmodulated (PWM single phase rectifier. A unified gyrator-based average model is developed for a general multi-active-bridge (MAB converter controlled through phase-shift modulation (PSM. Expressions to determine the power rating of the MAB ports are also derived. The developed gyrator-based average model is applied to the QAB converter for faster simulations of the proposed SST during the control design process as well for deriving the state-space representation of the plant. Both linear quadratic regulator (LQR and singleinput-single-output (SISO types of controllers are designed for the DC-DC stage. A novel technique that complements the SISO controller by taking into account the cross coupling characteristics of the QAB converter is also presented herein. Cascaded SISO controllers are designed for the AC-DC stage. The QAB demanded power is calculated at the QAB controls and then fed into the rectifier controls in order to minimize the effect of the interaction between the two SST stages. The dynamic performance of the designed control loops based on the proposed control strategies are verified through extensive simulation of the SST average and switching models.

  5. Emissions Tests Of Two Dc-To-Dc Converters

    Science.gov (United States)

    Mclyman, W. T.

    1992-01-01

    Report describes tests to characterize unwanted electric and magnetic fields, at frequencies up to few megahertz, radiated by two dc-to-dc converters, one 20-kHz square-wave converter; the other, a 33-kHz sine-wave converter. Part of effort to develop "quiet" power converter for use aboard spacecraft. Converter required to interfere minimally with delicate instruments measuring electric and magnetic fields.

  6. Hybrid battery with bi-directional DC/DC converter

    Directory of Open Access Journals (Sweden)

    DUDRIK Jaroslav

    2010-05-01

    Full Text Available Bi-directional buck-boost DC/DC converterfor hybrid battery is described in this paper. The firstpart of the paper is aimed at concept of hybrid battery;main advance compared to conventional accumulatoris explained there. Control circuit with UC3637 andpower circuit of the converter are described in thesecond part of the paper. Experimental results frommeasuring of converter are mentioned in the last part.

  7. Digital Control Technologies for Modular DC-DC Converters

    Science.gov (United States)

    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.

  8. Linking DC together with TRSL

    DEFF Research Database (Denmark)

    Haxthausen, Anne Elisabeth; Yong, X.

    2000-01-01

    Duration Calculus (DC) is an interval-based real-time logic, which can be used in capturing and eliciting users' real-time requirements. The Timed RAISE Specification Language (TRSL) is an extension of the RAISE Specification Language with real-time features. This paper links DC and TRSL together...... approach for linking state-based real-time logics together with event-based, timed process algebra languages....

  9. DC superconducting fault current limiter

    Science.gov (United States)

    Tixador, P.; Villard, C.; Cointe, Y.

    2006-03-01

    There is a lack of satisfying solutions for fault currents using conventional technologies, especially in DC networks, where a superconducting fault current limiter could play a very important part. DC networks bring a lot of advantages when compared to traditional AC ones, in particular within the context of the liberalization of the electric market. Under normal operation in a DC network, the losses in the superconducting element are nearly zero and only a small, i.e. a low cost, refrigeration system is then required. The absence of zero crossing of a DC fault current favourably accelerates the normal zone propagation. The very high current slope at the time of the short circuit in a DC grid is another favourable parameter. The material used for the experiments is YBCO deposited on Al2O3 as well as YBCO coated conductors. The DC limitation experiments are compared to AC ones at different frequencies (50-2000 Hz). Careful attention is paid to the quench homogenization, which is one of the key issues for an SC FCL. The University of Geneva has proposed constrictions. We have investigated an operating temperature higher than 77 K. As for YBCO bulk, an operation closer to the critical temperature brings a highly improved homogeneity in the electric field development. The material can then absorb large energies without degradation. We present tests at various temperatures. These promising results are to be confirmed over long lengths.

  10. Simulation and Implementation of Quasi Resonant DC-DC Converter

    Directory of Open Access Journals (Sweden)

    N. Devarajan

    2012-01-01

    Full Text Available Problem statement: A half-bridge LLC resonant converter with a voltage doubler rectifier has a simple structure and its Zero-Voltage-Switching (ZVS capability is excellent from zero to full load condition. But conduction loss is more due to high circulating energy thus reducing the system efficiency. Moreover a variable frequency control method makes the control circuits more complicated than those using the Pulse Width Modulation (PWM control method. Thus, DC drive has lower efficiency when it operates on light loads. Approach: To improve the efficiency of the DC drive under light loads, a PWM-controlled quasi-resonant converter is proposed .It has simple control circuits and less conduction loss compared to a half-bridge LLC resonant converter under light load conditions. The proposed converter has a half-bridge LLC resonant converter along with an auxiliary circuit. The load regulation of the proposed converter can be achieved by an auxiliary circuit. Thus the proposed converter is expected to be suitable sustaining power module for the efficiency enhancement of DC drives. As the magnetizing inductance of the proposed converter is larger the circulating energy is considerably reduced under light load conditions. In this study the operational principle, design and modeling of QRC DC-DC converters for DC drives are presented. The PWM controlled quasi resonant converter is implemented using PIC microcontroller 16F184A. Results: The capacitor filter in the output is replaced by pi filter to produce DC with minimum ripple. The experimental results and simulation results are compared. This converter has the advantages like reduced number of switches, reduced transformer and filter size, reduced ripple, reduced switching losses, reduced switching stresses and increased power density. Conclusion: The experimental results closely agree with the simulation results.

  11. Mono-switch AC-DC/DC-DC converter for single-phase UPS%单相UPS的单开关AC-DC/DC-DC变换电路

    Institute of Scientific and Technical Information of China (English)

    李宋; 叶满园; 袁义生

    2011-01-01

    A mono-switch AC-DC/DC-DC converter used in single-phase UPS system is introduced,which consists of one power switch and six diodes. As both AC-DC rectifier and DC-DC booster,its operating modes and working principle are detailed. The single-cycle nonlinear control is adopted,which applies two low-speed PI regulators to control the voltage of two capacitors on DC link and a high-speed PI regulator to control the input current. Simulative results prove that,being simple and reliable,it outputs stable DC bus voltage with high input power factor and low THD.%介绍了一种应用在单相UPS系统中的新型单开关AC-DC/DC-DC变换电路,该电路由1个功率开关器件和6个二极管组成,能够实现AC/DC整流和DC/DC升压2种功能.在详细分析了该电路运行模式及工作原理的基础上,采用了单周期非线性控制理论对其进行控制,利于2个低速PI调节器对直流母线上的2个电容器电压进行控制,1个高速PI调节器对输入电流进行控制.仿真结果表明,该电路简单可靠,输入功率因数高,电流谐波失真小,可以获得稳定的正负直流母线电压.

  12. Focus on: Washington Hospital Center, Biomedical Engineering Department.

    Science.gov (United States)

    Hughes, J D

    1995-01-01

    The Biomedical Engineering Department of the Washington Hospital Center provides clinical engineering services to an urban 907-bed, tertiary care teaching hospital and a variety of associated healthcare facilities. With an annual budget of over $3,000,000, the 24-person department provides cradle-to-grave support for a host of sophisticated medical devices and imaging systems such as lasers, CT scanners, and linear accelerators as well as traditional patient care instrumentation. Hallmarks of the department include its commitment to customer service and patient care, close collaboration with clinicians and quality assurance teams throughout the hospital system, proactive involvement in all phases of the technology management process, and shared leadership in safety standards with the hospital's risk management group. Through this interactive process, the department has assisted the Center not only in the acquisition of 11,000 active devices with a value of more than $64 million, but also in becoming one of the leading providers of high technology healthcare in the Washington, DC metropolitan area.

  13. Washington: a guide to geothermal energy development

    Energy Technology Data Exchange (ETDEWEB)

    Bloomquist, R.G.; Basescu, N.; Higbee, C.; Justus, D.; Simpson, S.

    1980-06-01

    Washington's geothermal potential is discussed. The following topics are covered: exploration, drilling, utilization, legal and institutional setting, and economic factors of direct use projects. (MHR)

  14. DC Hierarchical Control System for Microgrid Applications

    OpenAIRE

    Lu, Xiaonan; Sun, Kai; Guerrero, Josep M.; Huang, Lipei

    2013-01-01

    In order to enhance the DC side performance of AC-DC hybrid microgrid,a DC hierarchical control system is proposed in this paper.To meet the requirement of DC load sharing between the parallel power interfaces,droop method is adopted.Meanwhile,DC voltage secondary control is employed to restore the deviation in the DC bus voltage.The hierarchical control system is composed of two levels.DC voltage and AC current controllers are achieved in the primary control level.

  15. Pulsewidth modulated DC-to-DC power conversion circuits, dynamics, and control designs

    CERN Document Server

    Choi, Byungcho

    2013-01-01

    This is the definitive reference for anyone involved in pulsewidth modulated DC-to-DC power conversion Pulsewidth Modulated DC-to-DC Power Conversion: Circuits, Dynamics, and Control Designs provides engineers, researchers, and students in the power electronics field with comprehensive and complete guidance to understanding pulsewidth modulated (PWM) DC-to-DC power converters. Presented in three parts, the book addresses the circuitry and operation of PWM DC-to-DC converters and their dynamic characteristics, along with in-depth discussions of control design of PWM DC-to

  16. DC-DC converter for discharging energy storage magnets

    Science.gov (United States)

    Eyssa, Yehia M.; Huang, Xianrui

    1994-07-01

    A new DC-DC converter to control the output power delivered from a magnetic energy storage magnet or an equivalent current source is discussed. The circuit consists of: (1) highly coupled transformer (air or iron core) with coupling coefficient better than 0.95; (2) low frequency mechanical or superconducting switches (0.1 - 10 Hz) or high frequency (10 - 1000 Hz) GTO switches depending on the application; and (3) small voltage source (capacitor or battery) to control the output voltage. Two examples illustrating the application of this circuit are discussed. They are a step up dc current converter for use in uninterruptible power supplies and a step down one for use in discharging large current storage coil into a small current load. The efficiency expected to exceed 90%.

  17. Pulse-width modulated DC-DC power converters

    CERN Document Server

    Kazimierczuk, Marian K

    2008-01-01

    This book studies switch-mode power supplies (SMPS) in great detail. This type of converter changes an unregulated DC voltage into a high-frequency pulse-width modulated (PWM) voltage controlled by varying the duty cycle, then changes the PWM AC voltage to a regulated DC voltage at a high efficiency by rectification and filtering. Used to supply electronic circuits, this converter saves energy and space in the overall system. With concept-orientated explanations, this book offers state-of-the-art SMPS technology and promotes an understanding of the principle operations of PWM converters,

  18. Radiated electromagnetic emissions of DC-DC converters

    Energy Technology Data Exchange (ETDEWEB)

    Feld, L; Jussen, R; Karpinski, W; Klein, K; Sammet, J; Wlochal, M, E-mail: sammet@cern.ch [Physikalisches Institut IB, RWTH Aachen University, Aachen (Germany)

    2010-12-15

    For the CMS tracker at SLHC a new powering scheme is considered to be mandatory to allow the detector to provide at least the same performance as today at the LHC. The baseline solution of CMS foresees the use of DC-DC converters to provide larger currents with smaller losses. An important component of most converters are inductors which, however, tend to radiate the switching noise generated by the converter. The emissions of different inductors have been measured and simulated, the coil design has been optimized and noise susceptibility measurements, with present CMS hardware, have been performed. This article summarizes the results.

  19. Radiated electromagnetic emissions of DC-DC converters

    CERN Document Server

    Sammet, Jan Domenik

    2010-01-01

    A new powering scheme is considered to be mandatory for the CMS tracker at SLHC. The baseline solution of CMS foresees the use of DC-DC converters, allowing to provide larger currents while reducing losses. An important component of most converters are inductors, which, however, tend to radiate the switching noise generated by the converter. The radiated emissions of several converters have been measured and simulated. In addition noise susceptibility measurements with radiated noise and present CMS hardware have been performed. A summary of the results will be presented.

  20. Low dose failures of hardened DC-DC power converters

    Science.gov (United States)

    Lehman, J.; Yui, C.; Rax, B. G.; Miyahira, T. F.; Weideman, M.; Schrick, P.; Swift, G. M.; Johnston, A. H.

    2002-01-01

    Box-level total dose testing of the FOG (Fiber Optic Gyro) by IXSEA at ESA's GammabeamFacility were abruptly terminated at 8krad (Si) due to catastrophic failure (complete shutdown). This was unexpected because all components within the gyro were supposedly radiation tolerant. Further testing showed that the components responsible for the failure were two DC-DC converters, manufactured by Interpoint, that stopped regulating shortly before shutdown. This paper summarizes diagnostic test results for the converters to determine the underlying cause of the unexpected failure at low levels of radiation.

  1. Power flow analysis for DC voltage droop controlled DC microgrids

    DEFF Research Database (Denmark)

    Li, Chendan; Chaudhary, Sanjay; Dragicevic, Tomislav

    2014-01-01

    This paper proposes a new algorithm for power flow analysis in droop controlled DC microgrids. By considering the droop control in the power flow analysis for the DC microgrid, when compared with traditional methods, more accurate analysis results can be obtained. The algorithm verification...... is carried out by comparing the calculation results with detailed time domain simulation results. With the droop parameters as variables in the power flow analysis, their effects on power sharing and secondary voltage regulation can now be analytically studied, and specialized optimization in the upper level...... control can also be made accordingly. Case studies on power sharing and secondary voltage regulation are carried out using proposed power flow analysis....

  2. 77 FR 15179 - Disaster Declaration for Washington

    Science.gov (United States)

    2012-03-14

    ... Counties: Clallam, Grays Harbor, King, Klickitat, Lewis, Mason, Pierce, Skamania, Snohomish, Thurston... ADMINISTRATION [Disaster Declaration 13027 and 13028; Washington Disaster WA-00036] Disaster Declaration for Washington AGENCY: U.S. Small Business Administration. ] ACTION: Notice. SUMMARY: This is a Notice of...

  3. Aerospace Training. Washington's Community and Technical Colleges

    Science.gov (United States)

    Washington State Board for Community and Technical Colleges, 2014

    2014-01-01

    Aerospace is an economic powerhouse that generates jobs and fuels our economy. Washington's community and technical colleges produce the world-class employees needed to keep it that way. With about 1,250 aerospace-related firms employing more than 94,000 workers, Washington has the largest concentration of aerospace expertise in the nation. To…

  4. 75 FR 52048 - Washington Disaster #WA-00027

    Science.gov (United States)

    2010-08-24

    ... ADMINISTRATION Washington Disaster WA-00027 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of WASHINGTON dated 08/17/2010. Incident: Lynnview Apartment Complex Fire. Incident Period: 08/09/2010. Effective Date:...

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

    Science.gov (United States)

    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.

  6. Optimization of control sequences for DC-DC-converters; Optimierung der Stellgroessenfolge eines DC-DC-Wandler

    Energy Technology Data Exchange (ETDEWEB)

    Kroeger, Claus [Hochschule Aalen (Germany). Wirtschaftsingenieurwesen

    2009-07-01

    DC-DC-Converters are used in power electronics to adapt different voltage levels of electrical sources and sinks with respect of high efficiency. To minimize electrical losses these power electronic converters always work with switching power semiconductors. This switching principle of the converter is causing a control constraint which limits the achievable performance for the voltage control drastically. This paper presents an optimization for the control sequence in a high dynamic converter control which is based on the dead-beat control design. Thus the non-avoidable control constraint will not be violated. (orig.)

  7. An Integrated Multifunctional Bidirectional AC/DC and DC/DC Converter for Electric Vehicles Applications

    Directory of Open Access Journals (Sweden)

    Liwen Pan

    2016-06-01

    Full Text Available This paper presents an on-board vehicular battery charger that integrates bidirectional AC/DC converter and DC/DC converter to achieve high power density for application in electric vehicles (EVs. The integrated charger is able to transfer electrical energy between the battery pack and the electric traction system and to function as an AC/DC battery charger. The integrated charger topology is presented and the design of passive components is discussed. The control schemes are developed for motor drive system and battery-charging system with a power pulsation reduction circuit. Simulation results in MATLAB/Simulink and experiments on a 30-kW motor drive and 3.3-kW AC/DC charging prototype validate the performance of the proposed technology. In addition, power losses, efficiency comparison and thermal stress for the integrated charger are illustrated. The results of the analyses show the validity of the advanced integrated charger for electric vehicles.

  8. Quasi Y-Source Boost DC-DC Converter

    DEFF Research Database (Denmark)

    Siwakoti, Yam P.; Blaabjerg, Frede; Loh, Poh Chiang

    2015-01-01

    A new topology called “quasi-Y-source impedance network” is presented in this paper. It inherits all the advantages of the original Y-source network. In addition, the new topology draws continuous current from the source which is required for many renewable sources. It also has dc-current-blockin...

  9. Washington State biomass data book

    Energy Technology Data Exchange (ETDEWEB)

    Deshaye, J.A.; Kerstetter, J.D.

    1991-07-01

    This is the first edition of the Washington State Biomass Databook. It assess sources and approximate costs of biomass fuels, presents a view of current users, identifies potential users in the public and private sectors, and lists prices of competing energy resources. The summary describes key from data from the categories listed above. Part 1, Biomass Supply, presents data increasing levels of detail on agricultural residues, biogas, municipal solid waste, and wood waste. Part 2, Current Industrial and Commercial Use, demonstrates how biomass is successfully being used in existing facilities as an alternative fuel source. Part 3, Potential Demand, describes potential energy-intensive public and private sector facilities. Part 4, Prices of Competing Energy Resources, shows current suppliers of electricity and natural gas and compares utility company rates. 49 refs., 43 figs., 72 tabs.

  10. Marginal Iodine Status and High Rate of Subclinical Hypothyroidism in Washington DC Women Planning Conception.

    Science.gov (United States)

    Stagnaro-Green, Alex; Dogo-Isonaige, Emmerita; Pearce, Elizabeth N; Spencer, Carole; Gaba, Nancy D

    2015-10-01

    Subclinical hypothyroidism during pregnancy has been associated with adverse maternal and fetal outcomes. A subset of pregnant women in the United States have been shown to have mild iodine deficiency. No study has evaluated the thyroid and iodine status of women who are planning to become pregnant in the near future. Thyroid function tests, thyroid antibodies, and urine iodine levels were evaluated in women presenting for preconception screening and counseling. A thyrotropin (TSH) level above 3.0 mIU/L was considered abnormal. One hundred and forty one women enrolled in the study. The median TSH level was 1.70 mIU/L (range 0.43-5.3 mIU/L). Sixteen women (11%) had a TSH above the upper limit of normal (>3.0 mIU/L). Eleven women (8%) were positive for TPO-Ab and 21 women (15%) for TgAb. Twenty-three women (16%) were positive for at least one thyroid antibody (TPOAb and/or TgAb). Median serum TSH concentrations were higher in women with detectable antithyroid antibodies than in women who were antibody negative (2.2 mIU/L vs. 1.7 mIU/L; p=0.005). The median urinary iodine concentration was 100.5 μg (range 19-843 μg/L). The present cohort exhibited the lowest median urinary iodine concentration levels to date reported in the United States for women in their childbearing years. One out of every nine women (11%) had thyroid function tests consistent with subclinical hypothyroidism.

  11. 77 FR 37737 - Environmental Impact Statement for the Northeast Corridor Between Washington, DC, New York, NY...

    Science.gov (United States)

    2012-06-22

    ... overall scope, alternatives, approach and business case for proposed service and improvements. As part of... to be considered, environmental effects to be considered and evaluated, and methodologies to be used...

  12. Gold award: mental health services for the deaf--St. Elizabeths Hospital, Washington, D.C.

    Science.gov (United States)

    1978-10-01

    The mental health program for the deaf at St. Elizabeths Hospital offers comprehensive services to adolescents and adults who were born deaf or who became deaf early in life. A staff of 49, six of whom have impaired hearing, provide services to about 33 inpatients and about 71 outpatients. Activity therapies that do not require oral communication, such as occupational therapy, art therapy, dance therapy, and psychodrama, play an important role in the program, as does group psychotherapy. The program provides training, field experience, and consultation for workers throughout the U.S. and from foreign countries. Some guidelines for communicating with the deaf are given.

  13. 75 FR 39969 - National Mall and Memorial Parks, Washington, DC; Final Environmental Impact Statement and...

    Science.gov (United States)

    2010-07-13

    ... opportunities in adjacent parks, thereby contributing to the concept of healthy lifestyles, healthy parks, and healthy, more sustainable cities. Alternative A--Focus on the Historic Landscape and Education... demonstrations and other events. Alternative C--Focus on Urban Open Space, Urban Ecology, Recreation, and...

  14. A History of the Chemistry Division, Naval Research Laboratory, Washington, D.C., 1927-1982.

    Science.gov (United States)

    1983-04-22

    solutions of lithium hydroxide behave quite differently from aqueous solutions of sodium or potassium hydroxide in their reactions with steel in high...electrochemical processes, such as in corrosion, batteries, fuel cells, electroplating, electropolishing , electrochemical prepa- rations, and electrotwinning...and I noted that the inside of the ventilat- * ing du.zts were covered with sulphuric acid spray, and showed indicat-ions on the bottom that there had

  15. 76 FR 63841 - Security Zone; Potomac River, Georgetown Channel, Washington, DC

    Science.gov (United States)

    2011-10-14

    .... Background and Purpose The President is expected to attend the Martin Luther King, Jr. National Memorial... checklist and a categorical exclusion determination are available in the docket where indicated...

  16. 76 FR 51255 - Security Zone; Potomac River, Georgetown Channel, Washington, DC

    Science.gov (United States)

    2011-08-18

    .... Background and Purpose The President of the United States will be attending the Martin Luther King, Jr... temporary security zone. An environmental analysis checklist and a categorical exclusion determination...

  17. Health and housing outcomes from green renovation of low-income housing in Washington, DC.

    Science.gov (United States)

    Jacobs, David E; Breysse, Jill; Dixon, Sherry L; Aceti, Susan; Kawecki, Carol; James, Mark; Wilson, Jay

    2014-03-01

    Green building systems have proliferated recently, but studies are limited of associated health and housing outcomes. The authors measured self-reported resident physical and mental health, allergens, and building conditions at baseline and one-year follow-up in a low-income housing development being renovated in accordance with green healthy housing improvements (Enterprise Green Communities standards and Leadership in Energy & Environmental Design [LEED] gold certification). Self-reported general health in adults significantly improved from 59% to 67% (p = .026), with large statistically significant improvements in water/ dampness problems, cockroaches and rodents, and reduced pesticide use. Median cockroach (Bla g1) and mouse (Mus m1) allergen dust loadings showed large and statistically significant reductions from baseline to three months postintervention and were sustained at one year (both p Green Communities and LEED standards in low-income housing renovation improves health and housing conditions and can help to reduce disparities. All green housing standards should include health-related requirements.

  18. Toxicity of Anacostia River, Washington, DC, USA, sediment fed to mute swans (Cygnus olor)

    Science.gov (United States)

    Beyer, W.N.; Day, D.; Melancon, M.J.; Sileo, L.

    2000-01-01

    Sediment ingestion is sometimes the principal route by which waterfowl are exposed to environmental contaminants, and at severely contaminated sites waterfowl have been killed by ingesting sediment. Mute swans (Cygnus olor) were fed a diet for six weeks with a high but environmentally realistic concentration (24%) of sediment from the moderately polluted Anacostia River in the District of Columbia, to estimate the sediment?s toxicity. Control swans were fed the same diet without the sediment. Five organochlorine compounds were detected in the treated diets but none of 22 organochlorine compounds included in the analyses were detected in livers of the treated swans. The concentrations of 24 polynuclear aromatic hydrocarbons measured in the treated diet were as high as 0.80 mg/kg and they were thought to have been responsible for the observed induction of hepatic microsomal monooxygenase activity in livers. A concentration of 85 mg/kg of lead in the diet was enough to decrease red blood cell ALAD activity but was not high enough to cause more serious effects of lead poisoning. The dietary concentrations of Al, Fe, V, and Ba were high compared to the concentrations of these elements known to be toxic in laboratory feeding studies, but these elements did not accumulate in the livers of the treated swans and probably were not readily available in the sediment. Although ingestion of the Anacostia River sediment caused subtle toxicological effects in swans, we concluded from pathological examinations and weight data that the treated swans remained basically healthy.

  19. Image Understanding Proceedings of a Workshop Held at Washington, DC, April 23, 1981

    Science.gov (United States)

    1981-04-01

    aligned in an image (even though they may be separated by is known to be planar, the curva !ture of the shadow can be a gap of a considerable distan~ce...a discrete set of points. One possibility is to quadratic variation, which is defined to be use Coons p~atches, and Bezier and Ferguson surfaces fx2

  20. Annual Research Progress Report (U.S. Army Institute of Dental Research, Washington, DC)

    Science.gov (United States)

    1978-10-01

    evaluating self-repair denture irritation of the oral mucosa. The Maxillary Ameloblastoma : An Analysis of Twenty- Four Cases The maxillary... ameloblastoma presents clinically as a potentially more dangerous lesion than its mandibular counterpart. The microscopic appearance of this locally...systematically searched for all cases coded as ameloblastoma of the maxillae. The material included cases from the military, Veterans Administration, and

  1. Group Home Energy Efficiency Retrofit for 30% Energy Savings: Washington, D.C. (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2013-11-01

    Energy efficiency retrofits (EERs) face many challenges on the path to scalability. Limited budgets, cost effectiveness, risk factors, and accessibility impact the type and the extent of measures that can be implemented feasibly to achieve energy savings goals. Group home retrofits can face additional challenges than those in single family homes - such as reduced access (occupant-in-place restrictions) and lack of incentives for occupant behavioral change. This project studies the specification, implementation, and energy savings from an EER in a group home, with an energy savings goal of 30%. This short term test report chronicles the retrofit measures specified, their projected cost-effectiveness using building energy simulations, and the short term test results that were used to characterize pre-retrofit and post-retrofit conditions. Additionally, the final report for the project will include analysis of pre- and post-retrofit performance data on whole building energy use, and an assessment of the energy impact of occupant interface with the building (i.e., window operation). Ultimately, the study's results will be used to identify cost effective EER measures that can be implemented in group homes, given constraints that are characteristic of these buildings. Results will also point towards opportunities for future energy savings.

  2. Jay Haley's Invited address to the World Congress on Behaviour Therapy, Washington DC, 1983

    OpenAIRE

    Carr, Alan

    1984-01-01

    "Changes to a more sensible therapy" was the title of the paper Jay Haley presented to the 1983 World Congress on Behaviour Therapy. Haley began by pointing out that the idea of training mental health professionals to talk to patients, to change the patients' behaviour is relatively new. While the notion of healing by talking has been known to religious groups since early in our history, only recently has the phenomenon been subject to secular scrutiny.

  3. Proceedings: energy from urban wastes workshop, Washington, DC, September 11-12, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, A.S.; Brooks, C. (eds.)

    1979-06-01

    This workshop, for members of public interest groups, was sponsored by DOE's Urban Waste Technology Branch to provide information on the use of urban waste as an energy resource. A separate abstract was prepared for each of seven presentations plus the Summary of discussions. Two acts are included as appendices: (1) Public Law 95-238: Department of Energy Act of 1978 - Civilian Applications; and (2) Public Law 94-580: Resource Conservation and Recovery Act of 1976.

  4. Symposium on International Terrorism Held in Washington, DC on 2-3 December 1985

    Science.gov (United States)

    1985-12-01

    WONL c) (kC-’NATICJyAL r"PG$2 (SAL 12, PERSONA AUTHOR(S)I 13a. TYPE OF REPORT 13b. TIME COVERED 14. DATE OF REPORT (Year MonthDay) 5. PAGE COUNT FROM...domination du capital at de son idiologie " bien Strell, "gparantie socialel, "Wdroit. ou travail", sont bris65 par la bruta- Iit6 dos mosuros de

  5. Proceedings of the Acquisition Research Symposium Held in Washington, DC, October 1989

    Science.gov (United States)

    1989-10-01

    Korea, Taiwan , Hong Kong and Singapore (HBR «6, 1989, p.79). The currencies of these four listed places are linked to the U.S. dollar and they move...come readily to mind Still, even there, the spoken accent would mark the American CCO as a patent outsider But how about Japan. Korea and China (all...top management to keep the CEO, or surrogate, inforstad and to resolve problema beyond tha capability of the PM. Senior functional officers

  6. Annual Disruptive Technologies Conference (8th) Held in Washington, DC on November 8-9, 2011

    Science.gov (United States)

    2011-11-09

    6. Synthetic Biology • Life Science • Cultural and Behavioral • Training • Neuroscience • Medical Human Centric • Information Science...FY18 FY19 FY20 FY21  Data Preparation − Zoning (Source-specific) − OCR − ASR  Entity/Event Consolidation − Entity Coreference...Lingual OCR , 90% (TBD) Cross-Lingual ASR, 95% (TBD) D2D S&T Priority Initiatives 8 November 2011 Page-13 Distribution Statement A: Approved for

  7. AHS, Annual Forum, 46th, Washington, DC, May 21-23, 1990, Proceedings. Volumes 1 2

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    The present conference on helicopter technologies discusses the application of chaos methods to higher harmonic control of rotors, a FEM model reduction application to rotorcraft structure applications, the numerical simulation of powered-lift flows, V/STOL concepts for special applications, advanced rotorcraft transmissions, advanced helicopter avionics, three-dimensional shock-fitting for transonic rotor acoustics, a model-based procedure for low vibration rotor design generation, and an integrated aerodynamic load/dynamic approach to optimum rotor blade design. Also discussed are numerical optimization for tiltrotor blade aerodynamic design, aging U.S. Army aircraft, mission/task analysis for weapon system cost and risk reduction, night vision goggle compatibility with color displays in Army aircraft, the structural evaluation of a composite fuselage structure, composite actuators for airborne systems, wake surveys of advanced rotor platforms, safe strength/damage-tolerance assessment, cargo rotorcraft in future Army operations, tests of the V-22 flight control system, heliport/vertiport development, advanced surface-hardening technologies, and main rotorblade bonding automation.

  8. Group Home Energy Efficiency Retrofit for 30% Energy Savings: Washington, D.C. (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2013-11-01

    Energy efficiency retrofits (EERs) face many challenges on the path to scalability. Limited budgets, cost effectiveness, risk factors, and accessibility impact the type and the extent of measures that can be implemented feasibly to achieve energy savings goals. Group home retrofits can face additional challenges than those in single family homes - such as reduced access (occupant-in-place restrictions) and lack of incentives for occupant behavioral change. This project studies the specification, implementation, and energy savings from an EER in a group home, with an energy savings goal of 30%. This short term test report chronicles the retrofit measures specified, their projected cost-effectiveness using building energy simulations, and the short term test results that were used to characterize pre-retrofit and post-retrofit conditions. Additionally, the final report for the project will include analysis of pre- and post-retrofit performance data on whole building energy use, and an assessment of the energy impact of occupant interface with the building (i.e., window operation). Ultimately, the study's results will be used to identify cost effective EER measures that can be implemented in group homes, given constraints that are characteristic of these buildings. Results will also point towards opportunities for future energy savings.

  9. Proceedings of Nutrition Education Conference, February 20-22, 1967, Washington, D.C.

    Science.gov (United States)

    Agricultural Research Service (USDA), Washington, DC.

    Included are reports of present nutritional habits and problems in different communities, a discussion of psychological factors influencing consumer decisions about foods, and suggestions for the use of media such as magazines, newspapers, radio, and television to communicate basic nutritional concepts. Several new programs are reported concerned…

  10. Feasibility Study of Coal Gasification/Fuel Cell/Cogeneration Project. Washington, DC Site. Project Description

    Science.gov (United States)

    1985-06-01

    the cell stacks; - Maintenance for the expander, compresor and generator is typical of that for rotating equipment. Fuel cell stacks are periodically...steel, with mist eliminator designed for 157 psig at 150OF, 3’-8" diameter x 7’-6" high 0-204 Tar separator - coalescer plates in- stalled in fabricated

  11. Walter Reed Army Medical Center, Washington, DC Annual Progress Report FY-89. Volume 2. Part 1

    Science.gov (United States)

    1990-01-02

    levels dropped quite remarkably during the study. The third patient who will start the study in February 1989 is a patient who has had anorexia nervosa in... anorexia nervosa which she had in the past should not interfere with the scientific aspects or interpretation of this study. CONCLUSIONS None yet as...with respect to gender , rank and unit would not differ with respect to health risk (scores in the US Army’s Wellness Check, version 2.0); self

  12. The Role of Federal Troops in Quelling Civil Disturbance in Washington, DC, April 1968

    Science.gov (United States)

    1993-01-01

    shooting looters and to cease shooting out streetlights , which they had been doing because of their fear of snipers.ŕ 0 "Major General Charles P...vol. 2, third edition. New York: Harper Collins, 1991. Elliff, John T. Crime . Dissent and the Attorney General: The Justice Department in the 1960’s

  13. 78 FR 63250 - Workshop; November 18-19, 2013 in Washington, DC

    Science.gov (United States)

    2013-10-23

    ....'' Reservations also may be made on the hotel Web site: http://embassysuites.hilton.com/en/es/groups/personalized... rooms has been reserved at the hotel. To make a reservation for either or both meetings, attendees may... activities undertaken by the U.S. Department of Energy related to implementing the NWPA. Board members...

  14. Antitank Warfare Seminar Held in Washington, DC on 14-15 October 1976.

    Science.gov (United States)

    1976-10-01

    speaking: Dann kam eA auj daA Zile dauj an, wenn nuA 10 Panzex gemeLdet waxen, hind Wir nuL mit eine- Staijet, dazA hei44t theo&etizch 12 Ma6chinen, p...Col Rudel: Weitt vo-n, angeg4Zijen wwckde, wo die RuA.6en wditen. Wenn ex~ mekkte, dazA die Dut~chen in dek Meh.’tzaht 4&ind wo ekt ang’tei~en Aote

  15. World Materials Summit (3rd). Held in Washington, DC on 9-12 October, 2011

    Science.gov (United States)

    2012-05-23

    Materials360 electronic newsletter Immediately after the meeting ran highlights from some of the keynote and plenary presentations. Publicized Linkedln group...reliability Science for substitutions through materials discovery (alloys, nanomaterials, components): composition, structure and morphology \\ A

  16. Invited Speaker Support for SBP Conference Series (SBP 2014) held in April, 2014 in Washington, DC.

    Science.gov (United States)

    2014-07-23

    Network Structure and Propagation Dynamics for an Infectious Disease Louis Kim, Kimon Drakopoulos, Stephan Kolitz, Mark Abramson and Asuman Ozdaglar...Shashanka Ss Timmarajus, Mike Burmester and Xiuwen Liu SBP Poster Cholera and Water Treatment Behavior: Modeling the 󈧌-󈧍 Cholera Epidemic in...Environment Allows Engineers to Test and Evaluate Material Solutions Robert Demarco, Gordon Cooke, John Riedener and Elizabeth Mezzacappa BRiMS Poster

  17. Proceedings of Conference on Variable-Resolution Modeling, Washington, DC, 5-6 May 1992

    Science.gov (United States)

    1992-05-01

    and evaluacion (T&E) field. In addicion, JOTE is read by over 3000 professionals who desire Cechnology transfer and often seek coordination and...facilities, inulacioni , specific programs, management of T&E, criteria, the ’ilities, and evaluacion . JOTE also welcomes specialized papers on Che

  18. 75 FR 1406 - National Mall and Memorial Parks, Washington, DC; Notice of Availability of an Environmental...

    Science.gov (United States)

    2010-01-11

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE INTERIOR... nation, dating from 1790. The study area contains a significant concentration of our Nation's memorials...: If you wish to comment, you may submit your comments online by visiting...

  19. A Study of Translating the Weaving Art into Architecture : Carpet Museum in Washington DC

    OpenAIRE

    Bazrafshan, Sepideh

    2014-01-01

    CARPET is a mystery, It is not just woven one knot after the other It is a POEM, written one word after the other A SONG, composed one note after the other A PAINTING, done one color after the other A WALL, stacked one brick after (on) another. My architectural thesis began with the question of the relationship between the realm of the world most ancient craft and craft of building : The textile art and architecture. Two branches of art which are said their inve...

  20. Proceedings of the Seminar on Freelance Indexing (2nd, Washington, D.C., January 13, 1979).

    Science.gov (United States)

    Tebo, Jay D., Ed.

    Transcribed and edited from tape recordings and prepared papers, these proceedings present the topics covered in the four sessions of the Second Seminar on Freelance Indexing: (1) how to get started as an indexer--making contracts, setting up the office, billing and bookkeeping, reference tools, filing for trade-name, and indexing apprenticeship;…

  1. FAA Forecast Conference Proceedings (6th) Held at Washington, DC on 21 October 1980.

    Science.gov (United States)

    1980-10-01

    Hr, a • is the commuter market, which is the U.S.’s fastest - .. ,.. growing market. Figure 13 illustrates the first of these 12S tw o areas. Costo ...industrivs. I believe l.r,,ft types. that the exchange that this meeting fosters is a con- The total situation is not one leading to great op- structivV

  2. Cost-effectiveness of trees for demand-side management Washington, DC

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1992-12-01

    Trees can reduce demand for air conditioning to cool buildings by shading residences and lowering summertime air temperatures. During winter, trees can reduce heating needs by lowering wind speeds and thereby reducing infiltration of cold air. On the otherhand, winter shade from improperly located trees can increase heating requirements. Projections from computer simulations indicate that 100 million mature trees in U.S. cities (3 trees for every other single family home) could reduce energy use for heating and cooling by 30 billion kWh and reduce carbon dioxide emissions by as much as 9 million tons per year. This energy analysis is part of a larger study that quantifies costs and benefits of proposed tree plantings in 12 U.S. cities. While energy savings is an important benefit from community forests, other benefits (e.g., air quality improvement, reduced stormwater runoff, increased property values) can have equal or greater value. Tree planting, care, and other costs (e.g., water-sewer line repair, green waste disposal, litigation/liability, program administration) from the cost-benefit study can be used to help estimate costs associated with a tree planting program for demand-side management. Data from this energy analysis should be of direct value to local utilities, urban foresters, planners, landscape designers, and non-profit tree planting groups.

  3. Breakfast and Learning in Children. Symposium Proceedings (Washington, DC, April 22, 1999).

    Science.gov (United States)

    Food, Nutrition, and Consumer Services (USDA), Washington, DC. Center for Nutrition Policy and Promotion.

    Noting that many schools do not participate in the U.S. Department of Agriculture's School Breakfast Program despite evidence that poor nutrition affects children's school attendance and performance, this document presents the proceedings of a 1999 symposium on links between breakfast and school performance and the implications for public policy.…

  4. Proceedings of the AMEDD Psychology Symposium Held at Washington, DC on 27-31 October 1980

    Science.gov (United States)

    1983-12-01

    der Veen, Huebner, Jorgens, and Neja, 1964); Cb) Anxiety in all family members was assessed by the State-Trait Anxiety Scale (Speilberger, Gorsuch ...therapy. New ork: GAP, 1970. 藖 Speilberger, C.D., Gorsuch , R.L. and Lushene, R.E. Manual for the state-trait anxiety inventory. Palo Alto, CA

  5. Childhood Obesity: Causes and Prevention. Symposium Proceedings (Washington, DC, October 27, 1998).

    Science.gov (United States)

    Food, Nutrition, and Consumer Services (USDA), Washington, DC. Center for Nutrition Policy and Promotion.

    This report documents the proceedings of a 1998 symposium on the causes and prevention of childhood obesity sponsored by the U.S. Department of Agriculture (USDA) Center for Nutrition Policy and Promotion to focus attention on the growing problem of childhood obesity in the United States and the link between nutrition and health. Following opening…

  6. McMillan Pumping Station, Washington, D.C.; Hydraulic Model Investigation.

    Science.gov (United States)

    1980-09-01

    from the pump intake, dissipated some of the excessive kinetic energy of inflow, and essentially eliminated adverse effects of secondary crossflow...inside the prototype channel. A headbox in the model simulated the prototype channel and received water from each of the three pumps. The water was...baffled as it entered the headbox , then it was allowed to flow back into the sump through the four h8-in. (prototype) inflow pipes (simulated). Flow

  7. "Records of Rights": A New Exhibit at the National Archives in Washington, D.C.

    Science.gov (United States)

    Hussey, Michael

    2014-01-01

    America's founding documents--the Declaration of Independence, the Constitution, and the Bill of Rights--are icons of human liberty. But the ideals enshrined in those documents did not initially apply to all Americans. They were, in the words of Martin Luther King, Jr., "a promissory note to which every American was to fall heir."…

  8. From Oaxaca to Washington, D.C.: Community Museums as a Cultural and Economic Resource.

    Science.gov (United States)

    Levine, Carlisle J.

    1996-01-01

    The Smithsonian Institution's National Museum of the American Indian (NMAI) enhances perpetuation of indigenous communities through its "Fourth Museum" program that supports living community museums created by and located in indigenous communities of the Americas. Through education and financial and technical aid, NMAI helps community…

  9. Southeast Asia: Problems and Prospects Held at Washington, DC on 4-5 December 1984.

    Science.gov (United States)

    1985-06-01

    realize that economic ties were not enough, that a cultural element was also needed. They began to talk of person-to-person relationships. In practical...strength in Kelantan . The continued presence of Razaleigh in the cabinet following his two defeats lay in part in the danger that his dismissal might...Indonesians who have been under strong Javanese cultural influence view their collective future more in cyclical than in open or non-deterministic

  10. Conference on Workforce Quality Assessment Held in Washington, DC on 8 May 1989

    Science.gov (United States)

    1989-09-01

    quality is translated into action and operation. It is motivated and driven by quality, moved down the pyramid to the worker on the Its products are...culture, an organization that has a philosophy, a sustain quality but to enhance quality. You do clearly stated objective. Very, very importint. that...seconds. technical realm. While pay is not the end-all, or be-all, it is not number one on one’s hierarchical MS. SWIFT: Yes. list of needs, as Maslow

  11. Proceedings of the OMEGA Symposium (1st), 9 - 11 November, 1971, Washington, DC.

    Science.gov (United States)

    1971-01-01

    tiereivas’lrlcofedrtor ths Phae coute i t hi’ cn rvtr r . hiit a o iia Caduer d. This rnrnenbls ternal uancti coriutrtidu frorim the ce’itral conertcd fer inrtnna...velocity sources and the burst filter. the 0ItErA reoram tias exercised to run with different stations and rate aidinn sources. The MWEGA naviriatien data...OHlErCA pronram tias also run with no rate aidinn source. Proehiems wtith the dloppler radar hardware and software proaram did not permit the fOlErA

  12. "Records of Rights": A New Exhibit at the National Archives in Washington, D.C.

    Science.gov (United States)

    Hussey, Michael

    2014-01-01

    America's founding documents--the Declaration of Independence, the Constitution, and the Bill of Rights--are icons of human liberty. But the ideals enshrined in those documents did not initially apply to all Americans. They were, in the words of Martin Luther King, Jr., "a promissory note to which every American was to fall heir."…

  13. Experiments with a DC Motor

    Science.gov (United States)

    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…

  14. Washington International Renewable Energy Conference 2008 Pledges: Methodology and Assumptions Summary

    Energy Technology Data Exchange (ETDEWEB)

    Babiuch, B.; Bilello, D. E.; Cowlin, S. C.; Mann, M.; Wise, A.

    2008-08-01

    The 2008 Washington International Renewable Energy Conference (WIREC) was held in Washington, D.C., from March 4-6, 2008, and involved nearly 9,000 people from 125 countries. The event brought together worldwide leaders in renewable energy (RE) from governments, international organizations, nongovernmental organizations, and the private sector to discuss the role that renewables can play in alleviating poverty, growing economies, and passing on a healthy planet to future generations. The conference concluded with more than 140 governments, international organizations, and private-sector representatives pledging to advance the uptake of renewable energy. The U.S. government authorized the National Renewable Energy Laboratory (NREL) to estimate the carbon dioxide (CO2) savings that would result from the pledges made at the 2008 conference. This report describes the methodology and assumptions used by NREL in quantifying the potential CO2 reductions derived from those pledges.

  15. DC motor operation controlled from a DC/DC power converter in pulse mode with low duty cycle

    OpenAIRE

    Stefanov, Goce; Kukuseva, Maja; Citkuseva Dimitrovska, Biljana

    2016-01-01

    In this paper pulse mode of operation of DC motor controlled by DC/DC power converter is analyzed. DC motor operation with time intervals in which the motor operates without output load is of interest. In this mode it is possible the motor to restore energy. Also, in the paper are represented calculations for the amount of the restored energy in the pulse mode operation of the motor for different duty cycles.

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

    Science.gov (United States)

    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.

  17. Speed Control of DC Motor using AC/AC/DC Converter Based on Intelligent Techniques

    Directory of Open Access Journals (Sweden)

    Rakan Kh Antar

    2013-05-01

    Full Text Available    This paper describes the application of ac/ac/dc and ac/dc converters to control the speed of a separately excited DC motor. Artificial neural network and PI controller are trained to select the desired values of firing angles for triggering thyristors of the ac/ac/dc and ac/dc bridge converters in order to control the speed of the dc motor at a desired value with constant and different load torques in order to obtain the best speed response. Simulation results show that the rising time for ac/dc and ac/ac/dc converters at 250rpm are reduced about 79% and 89% respectively, while delay time it reduced about 69% and 64% respectively. Therefore, speed response of the dc motor is more efficient for closed loop system compared with open loop also the response of ac/ac/dc converter is better than ac/dc converter.

  18. Dilation and Curettage (D&C)

    Science.gov (United States)

    ... For Patients About ACOG Dilation and Curettage (D&C) Home For Patients Search FAQs Dilation and Curettage ( ... February 2016 PDF Format Dilation and Curettage (D&C) Special Procedures What is dilation and curettage (D& ...

  19. Dilation and Curettage (D&C)

    Science.gov (United States)

    ... For Patients About ACOG Dilation and Curettage (D&C) Home For Patients Search FAQs Dilation and Curettage ( ... February 2016 PDF Format Dilation and Curettage (D&C) Special Procedures What is dilation and curettage (D& ...

  20. Optimization of DC-DC Converters via Geometric Programming

    Directory of Open Access Journals (Sweden)

    U. Ribes-Mallada

    2011-01-01

    Full Text Available The paper presents a new methodology for optimizing the design of DC-DC converters. The magnitudes that we take into account are efficiency, ripples, bandwidth, and RHP zero placement. We apply a geometric programming approach, because the variables are positives and the constraints can be expressed in a posynomial form. This approach has all the advantages of convex optimization. We apply the proposed methodology to a boost converter. The paper also describes the optimum designs of a buck converter and a synchronous buck converter, and the method can be easily extended to other converters. The last example allows us to compare the efficiency and bandwidth between these optimal-designed topologies.

  1. RESONANT STEP-DOWN DC-DC POWER CONVERTERS

    DEFF Research Database (Denmark)

    2015-01-01

    charged from the input voltage and discharged to the output capacitor through the galvanic isolation barrier by a semiconductor switch arrangement in accordance with a switch control signal to produce the converter output voltage. The resonant step-down DC-DC power converter comprises an electrical short...... of the primary side circuit thereby establishing in both the first and second cases a series coupling of the output capacitor and the input capacitor. A load connection is established, in the first case, between the first positive electrode of the output capacitor and the positive input terminal or......-circuit connection across the galvanic isolation barrier connecting, in a first case, the second negative electrode of the output capacitor to the positive input terminal of the primary side circuit or, in a second case, connecting the second positive electrode of the output capacitor to the negative input terminal...

  2. DC/DC converter with improved rectification for higher efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Maisel, Peter; Saliternig, Martin [Continental AG, Nuernberg (Germany)

    2010-07-01

    High-power dc-dc converters are an important element of the electrical system of electric vehicles and hybrid electric vehicles. These complex modular components provide the link between the high-voltage level used for the powertrain and the low-voltage bus for the lighting system, engine management and auxiliary needs in the vehicle. The essential requirements for all converters are high efficiency, compact size, lightweight and reliability. A very popular method to increase the efficiency is the synchronous rectification. Parasitic inductances in the commutation circuit and reverse recovery effects can produce a ringing with voltage overshoots at the diodes and the transistors. These spikes can cause higher average power dissipation in the seminconductors and higher EMI (electromagnetic interference).

  3. Study of nonlinear phenomena in switching DC/DC converters

    Science.gov (United States)

    Iu, Herbert Ho-Ching

    This thesis studies some nonlinear phenomena such as bifurcation and chaos in DC/DC switching converters. Five phases of investigations are described. The first phase reviews the existing tools for analyzing nonlinear systems that are helpful to the investigation of nonlinear phenomena in power electronic circuits. Some of these existing tools are employed to study the nonlinear behaviour of power electronic circuits in the subsequent phases. The second phase focuses on the analysis of bifurcation behaviour of parallel-connected DC/DC converters under a master-slave current sharing scheme. An iterative discrete-time map and its Jacobian are established to predict the onset of period-doubling or Neimark-Sacker bifurcation. Both parallel-connected buck converters and boost converters are studied. The third phase studies an autonomous free-running Cuk converter under a hysteretic current-mode control. Hopf bifurcation is observed, for the first time, in this kind of autonomous power electronic circuits. The method of state-space averaging is employed to predict the occurrence of such bifurcation. Extensive simulations and experiments confirm the predicted results. A typical bifurcation sequence from stable fixed points to chaos, via limit cycles and quasiperiodic orbits, is demonstrated. The fourth phase investigates the possibility of synchronization of two chaotic autonomous free-running Cuk converters. With a particular capacitor voltage as driving signal, synchronization is found possible. Averaged state equations and conditional Lyapunov exponents are used to predict the possibility of synchronization while computer simulations and PSPICE simulations provide the verification. The last phase gives suggestions for future research.

  4. A simple DC-DC convertor of high accuracy

    CERN Document Server

    Hausler, M

    1974-01-01

    Origin and dimension of measurement faults are given for the application of a current source driven convertor having parallel ring transformers. Particularly described in this paper is the behaviour of this dc convertor at measurements taken near the zero point and at change of current polarity. The importance of an additional ring transformer in order to improve the ripple of the device is explained; hints to choose the optimal number of turns of the ring transformer are given. (2 refs).

  5. Mesoscopic electronics beyond DC transport

    Science.gov (United States)

    di Carlo, Leonardo

    Since the inception of mesoscopic electronics in the 1980's, direct current (dc) measurements have underpinned experiments in quantum transport. Novel techniques complementing dc transport are becoming paramount to new developments in mesoscopic electronics, particularly as the road is paved toward quantum information processing. This thesis describes seven experiments on GaAs/AlGaAs and graphene nanostructures unified by experimental techniques going beyond traditional dc transport. Firstly, dc current induced by microwave radiation applied to an open chaotic quantum dot is investigated. Asymmetry of mesoscopic fluctuations of induced current in perpendicular magnetic field is established as a tool for separating the quantum photovoltaic effect from classical rectification. A differential charge sensing technique is next developed using integrated quantum point contacts to resolve the spatial distribution of charge inside a double quantum clot. An accurate method for determining interdot tunnel coupling and electron temperature using charge sensing is demonstrated. A two-channel system for detecting current noise in mesoscopic conductors is developed, enabling four experiments where shot noise probes transmission properties not available in dc transport and Johnson noise serves as an electron thermometer. Suppressed shot noise is observed in quantum point contacts at zero parallel magnetic field, associated with the 0.7 structure in conductance. This suppression evolves with increasing field into the shot-noise signature of spin-lifted mode degeneracy. Quantitative agreement is found with a phenomenological model for density-dependent mode splitting. Shot noise measurements of multi-lead quantum-dot structures in the Coulomb blockade regime distill the mechanisms by which Coulomb interaction and quantum indistinguishability correlate electron flow. Gate-controlled sign reversal of noise cross correlation in two capacitively-coupled dots is observed, and shown to

  6. Implementation of hierarchical control in DC microgrids

    DEFF Research Database (Denmark)

    Jin, Chi; Wang, Peng; Xiao, Jianfang

    2014-01-01

    DC microgrids are becoming popular in low-voltage distribution systems due to the better compatibility with photovoltaic panels, electric vehicles, and dc loads. This paper presents a practical dc microgrid developed in the Water and Energy Research Laboratory (WERL) in the Nanyang University...

  7. Hierarchical Power Sharing Control in DC Microgrids

    DEFF Research Database (Denmark)

    Peyghami Akhuleh, Saeed; Mokhtari, Hossein; Blaabjerg, Frede

    2016-01-01

    Because of the advances in power electronics, DC-based power systems, have been used in industrial applications such as data centers [18], space applications [10], aircraft [12], offshore wind farms, electric vehicles [56], DC home systems [5, 20], and high-voltage DC transmission systems...

  8. DC-DC conversion powering for the CMS tracker at SLHC

    Energy Technology Data Exchange (ETDEWEB)

    Feld, L., E-mail: Lutz.Feld@cern.c [RWTH Aachen University, Sommerfeldstrasse 14, D-52074 Aachen (Germany); Jussen, R.; Karpinski, W.; Klein, K.; Merz, J.; Sammet, J. [RWTH Aachen University, Sommerfeldstrasse 14, D-52074 Aachen (Germany)

    2011-02-01

    A tracker powering scheme based on DC-DC converters close to the detector modules can supply more power through thinner cables. This will allow to satisfy the increased power demands of tracking systems at the SLHC. This article describes the development of DC-DC converters for upgrades of the CMS pixel and tracking systems and addresses system integration issues.

  9. DC-DC Conversion Powering for the CMS Tracker at SLHC

    CERN Document Server

    Feld, Lutz

    2010-01-01

    A tracker powering scheme based on DC-DC converters close to the detector modules can supply more power through thinner cables. This will allow to satisfy the increased power demands of tracking systems at the SLHC. This article describes the development of DC-DC converters for upgrades of the CMS pixel and tracking systems and addresses system integration issues.

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

    Science.gov (United States)

    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.

  11. A DC-DC Conversion Powering Scheme for the CMS Phase-1 Pixel Upgrade

    CERN Document Server

    Feld, Lutz Werner; Marcel Friedrichs; Richard Hensch; Karpinski, Waclaw; Klein, Katja; Sammet, Jan Domenik; Wlochal, Michael

    2012-01-01

    The powering scheme of the CMS pixel detector will be described, and the performance of prototype DC-DC buck converters will be presented, including power efficiency, system tests with DC-DC converters and pixel modules, thermal management, reliability at low temperature, and studies of potential frequency locking betwe...

  12. The DC-DC Conversion Power System of the CMS Phase-1 Pixel Upgrade

    CERN Document Server

    Klein, Katja

    2014-01-01

    The power system of the Phase-1 pixel detector will be described and the performance of the new components, including DC-DC converters, DC-DC converter motherboards and various power distribution boards, will be detailed. The outcome of system tests in terms of electrical behaviour, thermal management and pixel module performance will be discussed.

  13. A Survey on Voltage Boosting Techniques for Step-Up DC-DC Converters

    DEFF Research Database (Denmark)

    Forouzesh, Mojtaba; Siwakoti, Yam Prasad; Gorji, Saman Asghari;

    2016-01-01

    Step-up dc-dc converters are used to boost the voltage level of the input to a higher output level. Despite of its features such as simplicity of implementation, the fundamental boost dc-dc converter has shortcomings such as low boost ability and low power density. With these limitations, researc...

  14. AC-DC PFC Converter Using Combination of Flyback Converter and Full-bridge DC-DC Converter

    Directory of Open Access Journals (Sweden)

    Moh. Zaenal Efendi

    2014-06-01

    Full Text Available This paper presents a combination of power factor correction converter using Flyback converter and Full-bridge dc-dc converter in series connection. Flyback converter is operated in discontinuous conduction mode so that it can serve as a power factor correction converter and meanwhile Full-bridge dc-dc converter is used for dc regulator. This converter system is designed to produce a 86 Volt of output voltage and 2 A of output current. Both simulation and experiment results show that the power factor of this converter achieves up to 0.99 and meets harmonic standard of IEC61000-3-2. Keywords: Flyback Converter, Full-bridge DC-DC Converter, Power Factor Correction.

  15. Five-Level Active-Neutral-Point-Clamped DC/DC Converter for Medium-Voltage DC Grids

    DEFF Research Database (Denmark)

    Liu, Dong; Deng, Fujin; Chen, Zhe

    2017-01-01

    effectively eliminate high voltage leaps caused by the dead time effect. In addition, a capacitor voltage control strategy is proposed for the 5L-ANPC dc/dc converter to ensure the balanced flying capacitor voltage and desired five-level voltage waveforms. Finally, simulation and experimental studies......This paper proposes a five-level active-neutralpoint- clamped (5L-ANPC) dc/dc converter for applications in medium voltage dc (MVDC) grids. A modulation strategy is proposed for the 5L-ANPC dc/dc converter to generate multilevel voltage waveforms, which can effectively reduce voltage change rate dv...... are conducted, and the results have verified the proposed converter and control strategies....

  16. A Feed-Forward Control Realizing Fast Response for Three-Branch Interleaved DC-DC Converter in DC Microgrid

    Directory of Open Access Journals (Sweden)

    Haojie Wang

    2016-07-01

    Full Text Available It is a common practice for storage batteries to be connected to DC microgrid buses through DC-DC converters for voltage support on islanded operation mode. A feed-forward control based dual-loop constant voltage PI control for three-branch interleaved DC-DC converters (TIDC is proposed for storage batteries in DC microgrids. The working principle of TIDC is analyzed, and the factors influencing the response rate based on the dual-loop constant voltage control for TIDC are discussed, and then the method of feed-forward control for TIDC is studied to improve the response rate for load changing. A prototype of the TIDC is developed and an experimental platform is built. The experiment results show that DC bus voltage sags or swells caused by load changing can be reduced and the time for voltage recovery can be decreased significantly with the proposed feed-forward control.

  17. Southwestern Washington 36 arc-second DEM

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 36-second Southwest Washington Elevation Grid provides bathymetric data in ASCII raster format of 36-second resolution in geographic coordinates. This grid is...

  18. Willapa Bay, Washington Benthic Habitats 1995 Geodatabase

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In June 1995, the Columbia River Estuary Study Taskforce (CREST) acquired 295 true color aerial photographs (1:12,000) of Willapa Bay, Washington, from the State of...

  19. Willapa Bay, Washington Benthic Habitats 1995 Geoform

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In June 1995, the Columbia River Estuary Study Taskforce (CREST) acquired 295 true color aerial photographs (1:12,000) of Willapa Bay, Washington, from the State of...

  20. Willapa Bay, Washington Benthic Habitats 1995 Biotic

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In June 1995, the Columbia River Estuary Study Taskforce (CREST) acquired 295 true color aerial photographs (1:12,000) of Willapa Bay, Washington, from the State of...

  1. Willapa Bay, Washington Benthic Habitats 1995 Substrate

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In June 1995, the Columbia River Estuary Study Taskforce (CREST) acquired 295 true color aerial photographs (1:12,000) of Willapa Bay, Washington, from the State of...

  2. Timber resource statistics for southwest Washington.

    Science.gov (United States)

    Patricia M. Bassett; Daniel D. Oswald

    1981-01-01

    This report summarizes a 1978 timber-resource inventory of six counties in southwest Washington: Clark, Cowlitz, Lewis, Pacific, Skamania, and Wahkiakum. Detailed tables of forest area, timber volume, growth, mortality, and harvest are presented.

  3. Timber resource statistics for eastern Washington.

    Science.gov (United States)

    Patricia M. Bassett; Daniel D. Oswald

    1983-01-01

    This report summarizes a 1980 timber resource inventory of the 16 forested counties in Washington east of the crest of the Cascade Range. Detailed tables of forest area, timber volume, growth, mortality, and harvest are presented.

  4. Animals on the Washington Environmental Yard.

    Science.gov (United States)

    Moore, Robin; Wong, Herb

    1984-01-01

    Discusses various animal-related activities that took place in the natural resource area of the Washington Elementary School's (Berkeley, CA) environmental yard. The "yard" is open 24 hours a day and is freely accessible to informal users. (JN)

  5. EAARL Topography George Washington Birthplace National Monument

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare earth elevation map (also known as a Digital Elevation Model or DEM) of George Washington Birthplace National Monument was produced from remotely-sensed,...

  6. Cooperative Planning in Action: The Washington Experiment

    Science.gov (United States)

    Gell, Marilyn

    1976-01-01

    Library cooperation in the Metropolitan Washington area is described, along with its problems and successes, and the significant role special libraries can play in an ambitious intertype library cooperative. (Author/PF)

  7. EAARL Topography George Washington Birthplace National Monument

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare earth elevation map (also known as a Digital Elevation Model or DEM) of George Washington Birthplace National Monument was produced from remotely-sensed,...

  8. Southwestern Washington 6 arc-second DEM

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 6-second Southwest Washington Elevation Grid provides bathymetric data in ASCII raster format of 6-second resolution in geographic coordinates. This grid is...

  9. Transformerless dc-Isolated Converter

    Science.gov (United States)

    Rippel, Wally E.

    1987-01-01

    Efficient voltage converter employs capacitive instead of transformer coupling to provide dc isolation. Offers buck/boost operation, minimal filtering, and low parts count, with possible application in photovoltaic power inverters, power supplies and battery charges. In photovoltaic inverter circuit with transformerless converter, Q2, Q3, Q4, and Q5 form line-commutated inverter. Switching losses and stresses nil because switching performed when current is zero.

  10. Power Network impedance effects on noise emission of DC-DC converters

    Science.gov (United States)

    Esteban, M. C.; Arteche, F.; Iglesias, M.; Gimeno, A.; Arcega, F. J.; Johnson, M.; Cooper, W. E.

    2012-01-01

    The characterization of electromagnetic noise emissions of DC-DC converters is a critical issue that has been analyzed during the desing phase of CMS tracker upgrade. Previous simulation studies showed important variations in the level of conducted emissions when DC-DC converters are loaded/driven by different impedances and power network topologies. Several tests have been performed on real DC-DC converters to validate the Pspice model and simulation results. This paper presents these test results. Conducted noise emissions at the input and at the output terminals of DC-DC converters has been measured for different types of power and FEE impedances. Special attention has been paid to influence on the common-mode emissions by the carbon fiber material used to build the mechanical structure of the central detector. These study results show important recommendations and criteria to be applied in order to decrease the system noise level when integrating the DC-DC.

  11. 30 CFR 947.700 - Washington Federal program.

    Science.gov (United States)

    2010-07-01

    ... Forest Practices Act, RCW 76.09. (5) Washington Water Code, RCW 90.03. (6) Washington Water Pollution Control Act, RCW 90.48. (7) Washington Minimum Water Flows and Levels Act, RCW 90.22. (8) Washington... necessary because of the nature of the terrain, climate, biological, chemical, or other relevant physical...

  12. FLYWHEEL AND A DC MACHINE

    Directory of Open Access Journals (Sweden)

    IVAN ALCALÁ

    2014-01-01

    Full Text Available Este artículo describe el análisis, modelado y simulación de un vehículo eléctrico (EV enfocado al desarrollo de un banco de pruebas para reproducir la dinámica del EV. El banco está formado por un drive de motor de inducción (IM acoplado directamente a una máquina de DC y a un volante de inercia a través de una transmisión. El volante de inercia y la máquina de DC reproducen la dinámica y las fuerzas que actúan en el vehículo. Se propone una metodología para diseñar un banco de pruebas de EV para estudiar el comportamiento de vehículos eléctricos cercano a las condiciones de operación reales. El análisis de las fuerzas en el EV en conjunto con la máquina DC define las condiciones de operación del EV. El modelado y la simulación son desarrollados en MATLAB/Simulink, el banco de pruebas implementado es controlado por un DSP. Finalmente, los resultados de simulación y experimentales obtenidos validan el funcionamiento del banco de prueba.

  13. DC

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    金属材质机身拥有三层镀膜工艺,1210万像素CCD,采用4倍变焦28mm广角镜头。配合16:9屏幕以及720p高清短片拍摄为卖点.整体感觉有别于佳能一贯的风格。

  14. DC

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    近期.单反市场最受期待的产品非尼康D40x莫属了,D40x的上市弥补了尼康在低价位千万像素级别无产品的空白,形成了其完整的产品线,D200、D80,D40x和D40.随着D70s的停产,D40x充当这一价位的角色,直接挑战佳能400D及索尼a100.目前千万像素已经普及到了低档单反之中,不难看出尼康D40x是2007年单反市场中的一颗重磅炸弹,相信随着D40x的上市单反的价格战又会再次拉开。

  15. DC

    Institute of Scientific and Technical Information of China (English)

    姚文秋

    2005-01-01

    阳春三月,细雨绵绵,冷却了火爆的年前DC市场,但是也活跃离一部分即将崭露头角的新芽。纵观市场,几大品牌中要数尼康的销售情况最好,这主要是尼康的机器价位合理,外形时尚,功能全面,品质优良。比如尼康5200,这款机器500万像素,才两多块,而且外观十分小巧,性价比很高。

  16. DC

    Institute of Scientific and Technical Information of China (English)

    姚文秋

    2005-01-01

    八月,驴友们的黄金时节。九寨沟清凉的水、张家界翠绿的树、黄山神秘的云雾……都是大家向往的好去处。拿起自己心爱的DC把这些美景定格保留作为美好的纪念是必不可少啦。而厂商们当然不会放过暑期这最后的机会,力求分得暑期市场的最后一块蛋糕。总而言之,与硝烟弥漫的七月市场相比,本月DC市场仍然延续着上月的强劲势头。

  17. DC

    Institute of Scientific and Technical Information of China (English)

    姚文秋

    2005-01-01

    纵观年底DC市场,风云变幻,惊喜不断。各大DC厂商纷纷对自己的产品价格进行调整。降价似乎成了最主流的声音。市场霸主佳能继PowerShot S50在市场上大获成功之后,在今年夏天紧接着发布了其第一款5百万像素的相机PowerShot S60,近这款数码相机做了一次大的价格调整。另外,随着家庭用户要求的不断增加,更高水平的家用数码相机也浮出水面。

  18. DC

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    一般来说数码相机镜头等效焦距在200mm以上的机型,就可以称之为长焦相机。长焦数码相机因其超长的焦距、丰富的功能受到了消费者的喜爱,它们也一直是消费级数码相机市场的热点所在。但是由于过大的体积,让携带长焦相机成为一件很费力的事情。现在,随着机身设计的进一步轻便和防抖技术的进一步成熟,长焦相机正在逐渐变得更加小巧、实用。原来拥有超长焦距的机型现在也可以像卡片机一样随身携带,近期上市的索尼DSC—H3就是其中不错的一款。

  19. DC

    Institute of Scientific and Technical Information of China (English)

    姚文秋

    2005-01-01

    DC市场在经过10月份的促销鏖战之后,行情慢慢稳定下来,各个厂家也不断推出自己在2005下半年的主流DC。家用机和长焦数码已经进入了一个新格局。以前我们耳熟能详的佳能A95、尼康5900等一批经典机型已经慢慢退下一线,取而代之的最新产品昂首进入激烈的数码相机战场。而时尚轻薄是在这些新品中刮起来的一阵旋风。

  20. DC

    Institute of Scientific and Technical Information of China (English)

    姚文秋

    2005-01-01

    进入七月,学校都已放假,不少学生教师也将外出旅游当作假期第一选择。要外出旅游当然少不了带上心爱的DC啦。有需求就会有供给,这是市场规律的铁定原则,因此各大厂商自然不会错过机会一一推新的推新、降价的降价。整个市场一片热火朝天的场面。

  1. DC

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    本月市场动态:第十届中国国际照相机械影像器材与技术博览会(2007 CHINA P&E)于7月1日在北京落幕,作为目前中国规模最大的摄影器材展会,其影响力不言而喻。国际知名的几大品牌,如佳能.尼康,索尼均带来了主流的产品,腾龙、适马也推出了各自最新的镜头。从展出的产品来看.有一个非常明显的信号就是,

  2. SDF-1, DC1/DC2, and Tumor Angiogenesis

    Science.gov (United States)

    2006-04-01

    However, the presence of functional immunogenic (mature) myeloid DCs is rare in human ovarian tumours35, breast tumours40,41, prostate cancer42 and...cyclooxygenase-2 ( COX2 )50–52. COX2 promotes prostaglandin E2 (PGE2) production in the tumour environment. PGE2 in turn suppresses DC differentiation and...Abundance of VEGF, IL-6, M-CSF, TGFβ, IL-10, COX2 , PGE2, gangliosides and other suppressive molecules versus negligible GM-CSF, IL-4, B7-H1 A recently

  3. A Feedback Passivation Design for DC Microgrid and Its DC/DC Converters

    Directory of Open Access Journals (Sweden)

    Feifan Ji

    2016-12-01

    Full Text Available There are difficulties in analyzing the stability of microgrids since they are located on various network structures. However, considering that the network often consists of passive elements, the passivity theory is applied in this paper to solve the above-mentioned problem. It has been formerly shown that when the network is weakly strictly positive real (WSPR, the DC microgrid is stable if all interfaces between the microgrid and converters are made to be passive, which is called interface passivity. Then, the feedback passivation method is proposed for the controller design of various DC–DC converters to achieve the interface passivity. The interface passivity is different from the passivity of closed-loop systems on which the passivity based control (PBC concentrates. The feedback passivation design is detailed for typical buck converters and boost converters in terms of conditions that the controller parameters should satisfy. The theoretical results are verified by a hardware-in-loop real-time labotray (RTLab simulation of a DC microgrid with four generators.

  4. DC Voltage Droop Control Implementation in the AC/DC Power Flow Algorithm: Combinational Approach

    DEFF Research Database (Denmark)

    Akhter, F.; Macpherson, D.E.; Harrison, G.P.

    2015-01-01

    In this paper, a combinational AC/DC power flow approach is proposed for the solution of the combined AC/DC network. The unified power flow approach is extended to include DC voltage droop control. In the VSC based MTDC grids, DC droop control is regarded as more advantageous in terms...... of operational flexibility, as more than one VSC station controls the DC link voltage of the MTDC system. This model enables the study of the effects of DC droop control on the power flows of the combined AC/DC system for steady state studies after VSC station outages or transient conditions without needing...... to use its complete dynamic model. Further, the proposed approach can be extended to include multiple AC and DC grids for combined AC/DC power flow analysis. The algorithm is implemented by modifying the MATPOWER based MATACDC program and the results shows that the algorithm works efficiently....

  5. Dubois and Washington -- Opposite or Similar: An Evaluation of the Philosophies of Washington and Dubois.

    Science.gov (United States)

    Reedom, John Anthony

    Although comparative analysis of the philosophies of Booker T. Washington and W.E.B. DuBois reveals significant differences in preferred solutions to problems of blacks in the United States, the philosophies of the two men are not as diametrically opposed as scholars have generally maintained. Washington's philosophy was one of conciliation…

  6. Energy Factor and Mathematical Modeling for Power DC/DC Converters

    Institute of Scientific and Technical Information of China (English)

    Fang Lin LUO; Hong YE

    2004-01-01

    Mathematical modelling for power DC/DC converters is a historical problem accompanying DC/DC conversion technology since 1940's. The traditional mathematical modelling is not available for complex structure converters since the differential equation order increases very high. We have to search other way to establish mathematical modelling for power DC/DC converters. We have theoretically defined a new concept - Energy Factor (EF) in this paper and researched the relations between EF and the mathematical modelling for power DC/DC converters. EF is a new concept in power DC/DC conversion technology, which thoroughly differs from the traditional concepts such as power factor (PF), power transfer efficiency (η), total harmonic distortion (THD) and ripple factor (RF). EF and the subsequential EFv (and EFvD ) can illustrate the system stability, reference response and interference recovery. This investigation is very helpful for system design and DC/DC converters characteristics foreseeing. Two DC/DC converters: Buck converter and Super-Lift Luo-Converter as the samples are analysed in this paper to demonstrate the applications of EF, EFv (and EFvD), PE,SE, VE (and VED ), time constant τ and damping time constant τd .

  7. Silicon carbide DC-DC multilevel Cuk converter

    Science.gov (United States)

    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.

  8. DC Magnetics Measurement System Design

    Science.gov (United States)

    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.

  9. Linking DC together with TRSL

    DEFF Research Database (Denmark)

    Haxthausen, Anne; Yong, Xia

    1999-01-01

    of constraints on the durations of states of the system, i.e. at a high level of abstraction.However, as a state-based logic, it lacks the ability to specifysequential programs and communicating concurrent processes at a concrete level. The Timed RAISE Specification Language (TRSL) [XG99] has this ability...... (parts of) the history of the observables of the system,and then define a satisfaction relation in terms of behaviours. DC has previously been linked together with subsets of other event-based process algebra languages, but using another approach:the event-based languages were given a denotational...

  10. Power factor controller used as DC-DC converter for photovoltaic sources

    Energy Technology Data Exchange (ETDEWEB)

    Mukerjee, A.K.; Dasgupta, Nivedita [Centre for Energy Studies, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016 (India)

    2008-06-15

    An active power factor controller (PFC) integrated circuit, normally used in AC circuits, has been used for DC-to-DC boost conversion with a stable output voltage for a variable DC input voltage as obtained from photovoltaic (PV) sources. The circuit described here uses a power factor controller MC 34262 to give approximately 400 V{sub DC} output for an input variation from 90 to 280 V{sub DC}. The maximum efficiency achieved was 98% at 450 W. Comparisons between AC and DC operations have been made. (author)

  11. Chaos analysis and chaotic EMI suppression of DC-DC converters

    CERN Document Server

    Zhang, Bo

    2014-01-01

    Introduces chaos theory, its analytical methods and the means to apply chaos to the switching power supply design DC-DC converters are typical switching systems which have plenty of nonlinear behaviors, such as bifurcation and chaos. The nonlinear behaviors of DC-DC converters have been studied heavily over the past 20 years, yet researchers are still unsure of the practical application of bifurcations and chaos in switching converters. The electromagnetic interference (EMI), which resulted from the high rates of changes of voltage and current, has become a major design criterion in DC-DC co

  12. Elimination of output voltage oscillations in DC-DC converter using PWM with PI controller

    Directory of Open Access Journals (Sweden)

    Sreenivasappa Veeranna Bhupasandra

    2010-01-01

    Full Text Available In this paper the SIMULINK model of a PWM controlled DC-DC converter is modeled using switching function concept to control the speed of the DC motor. The presence of the voltage oscillation cycles due to higher switching frequency in the DC-DC converter is identified. The effect of these oscillations on the output voltage of the converter, Armature current, Developed torque and Speed of the DC motor is analyzed. In order to minimize the oscillation cycles the PI controller is proposed in the PWM controller.

  13. Hierarchical Velocity Control Based on Differential Flatness for a DC/DC Buck Converter-DC Motor System

    Directory of Open Access Journals (Sweden)

    R. Silva-Ortigoza

    2014-01-01

    Full Text Available This paper presents a hierarchical controller that carries out the angular velocity trajectory tracking task for a DC motor driven by a DC/DC Buck converter. The high level control is related to the DC motor and the low level control is dedicated to the DC/DC Buck converter; both controls are designed via differential flatness. The high level control provides a desired voltage profile for the DC motor to achieve the tracking of a desired angular velocity trajectory. Then, a low level control is designed to ensure that the output voltage of the DC/DC Buck converter tracks the voltage profile imposed by the high level control. In order to experimentally verify the hierarchical controller performance, a DS1104 electronic board from dSPACE and Matlab-Simulink are used. The switched implementation of the hierarchical average controller is accomplished by means of pulse width modulation. Experimental results of the hierarchical controller for the velocity trajectory tracking task show good performance and robustness against the uncertainties associated with different system parameters.

  14. DC operating points of transistor circuits

    Science.gov (United States)

    Trajkovic, Ljiljana

    Finding a circuit's dc operating points is an essential step in its design and involves solving systems of nonlinear algebraic equations. Of particular research and practical interests are dc analysis and simulation of electronic circuits consisting of bipolar junction and field-effect transistors (BJTs and FETs), which are building blocks of modern electronic circuits. In this paper, we survey main theoretical results related to dc operating points of transistor circuits and discuss numerical methods for their calculation.

  15. Control of Parallel DC/DC Converters in DC Microgrid%直流微网中平行DC/DC变换器的控制

    Institute of Scientific and Technical Information of China (English)

    叶友泉; 杨冠鲁

    2016-01-01

    提出以多墙体光伏为研究对象的光伏直流微网系统。将在逆变器并联控制中广泛使用的下垂控制策略应用到平行DC/DC变换器的控制中,与电压、电流环构成三闭环控制,从而抑制平行DC/DC变换器之间的环流。通过Simulink 仿真分析,该方法能够实现直流母线电压的稳定及有效抑制各平行DC/DC变换器之间的环流。最后,在实验室搭建实验平台,验证该控制策略的可行性。%This article proposes a photovoltaic ( PV) DC microgrid system which employs multi-wall PV. In the DC microgrid, the droop control strategy widely used in parallel control of inverter is adopted for the control of parallel DC/DC converters, forming a triple-loop control together with voltage and current loops, which restrains the loop current between parallel DC/DC converters. Simulink simulation shows that, stable DC bus voltage and effective control over the loop current among parallel DC / DC converters can be achieved by this way. In the end, an experimental platform is built in the lab to verify the feasibility of this control strategy.

  16. How Much DC Power is Necessary

    Science.gov (United States)

    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

  17. Energy Evaluation for DC/DC Converters in DC-Based Wind Farms

    Energy Technology Data Exchange (ETDEWEB)

    Max, Lena

    2007-02-15

    In this thesis the suitability of three topologies for DC/DC converters in a DC wind farm grid is investigated from an energy efficiency and energy production cost point of view. The three selected topologies are the fullbridge converter, the single active bridge converter and the series parallel resonant converter. The losses are calculated for all three topologies as a function of the wind speed considering the losses in the semiconductor components and in the transformer. To obtain the average losses, the losses for each converter are integrated over the wind distribution for different average wind speeds. It is found that the resonant converter has the lowest losses of the three types for the DC wind farm application with power losses of about 2.0 - 2.5 % of the input power and the fullbridge converter has slightly higher losses with 2.3 - 3.5 % losses depending on the position in the wind turbine grid. The single active bridge converter has considerably higher losses than the other two topologies with 3.5 - 5.0 % losses. It is shown that the variable operating conditions create problems for all three converters, and as mentioned the single active bridge converter is most affected by the wide range of operation conditions. When comparing the resonant converter and the fullbridge converter, the fullbridge converter has a smaller transformer as well as lower peak current and peak voltage, but also a higher number of diode modules in the output bridge. Comparing the contribution to the energy production cost for the converters, the topology with the lowest contribution varies between the positions in the wind turbine grid. For some positions, the cost of the higher losses for the fullbridge converter are compensated by lower investment cost for the fullbridge converter compared to the resonant converter. Considering the resonant capacitor, the higher peak voltage and the variable frequency control for the resonant converter, the fullbridge converter is here found

  18. Anencephaly: An Ongoing Investigation in Washington State.

    Science.gov (United States)

    Barron, Sara

    2016-03-01

    : In the spring of 2012, a nurse in Washington State detected a cluster of babies born with anencephaly-a fatal condition in which infants are born without parts of the brain or skull. The resulting investigation initially confirmed a rate of anencephaly between January 2010 and January 2013 of 8.4 per 10,000 live births-more than four times the national average. As of November 2015, cases of anencephaly in Washington State have continued to increase, with the current rate estimated at 9.5 per 10,000 live births. While no distinct cause has yet been determined, neural tube defects-including anencephaly-are known to have multiple causes, including folic acid deficit, genetic variants in the folate pathway, and exposure to a variety of environmental and occupational toxins. This article describes many of these risk factors and explores the findings of Washington's ongoing investigation.

  19. The Washington Biologists' Field Club : Its members and its history (1900-2006)

    Science.gov (United States)

    Perry, M.C.

    2007-01-01

    This book is based on the interesting one-hundred-plus-year history of the Club and its members. Plummers Island and the historic cabin on the Island have served as a common meeting area where the Club members have conducted research and held many social activities for over a century. The history has been written and revised over the years by members, and the biographical sketches also have been collected and written by the members. The Club was formed in 1900 and incorporated as a society in 1901 for scientists in the Washington, D.C., area. In recent years the Club has sponsored research by many non-member local scientists with grants totaling over $305,000. The cumulative total of 267 members represents all branches of natural science, with a strong emphasis on biology as the Club name indicates. In addition to the biologists there have been famous naturalists (e.g., John Burroughs), high-level administrators (e.g., Ira Gabrielson), and well-known artists (e.g., Roger Tory Peterson). Most members have been biological scientists, working for agencies in the Washington, D.C., area, who have published many articles and books dealing with biology and related subjects. The book is publIshed mainly for the benefit of the living Club members and for relatives of the deceased members. The members hope that the book will find its way into libraries across the country and that in the future, persons interested in some of the pioneer scientists, in the various professional areas of science, can obtain biographical information from a well-documented source. Most of the 542 illustrations of the members, cabin, and the Island have not been published previously. It is hopeful that the biographical sketches, pictures, and other information presented in this book can generate new information for future publications and for the website of the Washington Biologists' Field Club, which is updated frequently.

  20. Zero-voltage switching technique in dc/dc converters

    Science.gov (United States)

    Liu, Kwang-Hwa; Lee, Fred C. Y.

    1990-07-01

    A novel resonant switch operating under the principle of zero-voltage switching is presented. In contrast to the zero-current switching, this technique eliminates the switching loss and dv/dt noise due to the discharging of MOSFET junction capacitances and the reverse recovery of diodes, and enables the converters to operate at high frequencies. A dc analysis of the converter is carried out. The duality relationship between the zero-current switching technique and the zero-voltage switching technique is derived. The two techniques are compared using an example showing the duality between a current-mode quasi-resonant Buck converter and a voltage-mode quasi-resonant boost converter. A 5-MHz 50 V to 5 V flyback converter employing the zero-voltage switching technique has been implemented. The circuit contains the smallest number of components possible, and yet maintains high efficiency at high switching frequency.

  1. SIMPLIFIED APPROACHES FOR CONTROLLING DC-DC POWER CONVERTERS

    Directory of Open Access Journals (Sweden)

    M. M. ABDEL AZIZ

    2012-02-01

    Full Text Available This paper represents the design procedures of different compensation schemes for voltage mode controlled (VMC dc–dc switching converters. Proportional integral derivative (PID controllers, Fuzzy logic controllers (FLC, parallel combination of PID and FLC, and FLC tuned by PI controller have been investigated. MATLAB software is used to depict the buck converter performance with each compensator type when it is electrically simulated, and analytically modeled using its equivalent transfer function (TF. The comparative study Resultsemphasize that FLC tuned by PI controller is superior to the other control strategies because of fast transient response, minimum steady state error and good disturbance rejection under various variations of the operating conditions. Hence, it achieves the most tightly output voltage regulation.

  2. Teaching about operation of brushless DC motors

    OpenAIRE

    Čufar, Aleksandra

    2013-01-01

    Brush DC motor is being replaced by brushless DC motors on every area of application. My diploma thesis is a presentation of brushless DC motor, how it works and its application. Within first part we describe various electric motors and their application. There are several types of electric motors division. Last to be added is a brushless motor. Within second part of thesis we look into a brushless DC motor, how it works, its application and control. In the third part of thesis we construct a...

  3. The good routing of a non-insulated DC/DC converter; Bien router un convertisseur DC/DC non-isole

    Energy Technology Data Exchange (ETDEWEB)

    Lenoir, E.

    2001-03-01

    DC to DC converters are important sources of magnetic and electric fields with frequencies that can exceed 100 MHz. Thus, their positioning on a circuit board is of prime importance to minimize the magnetic and capacitive couplings with other parts and components of the circuit. This article summarizes the important rules to follow for a good routing of non-insulated switching DC/DC converters: taking the ohmic voltage drops into consideration, managing the MOSFET commutation, limiting the current loop disturbances, correct routing of power tracks. (J.S.)

  4. DC-SIGN:Binding receptor for HCV?

    Institute of Scientific and Technical Information of China (English)

    Zhi-Hua Feng; Quan-Chu Wang; Qing-He Nie; Zhan-Sheng Jia; Yong-Xin Zhou

    2004-01-01

    DC-SIGN, a dendritic Cell-specific adhesion receptor and a type Ⅱ transmembrane mannose-binding C-type lectin, is very important in the function of DC, both in mediating naive T cell interactions through ICAM-3 and as a rolling receptor that mediates the DC-specific ICAM-2-dependent migration processes. It can be used by viral and bacterial pathogens including Human Immunodeficiency Virus (HIV), HCV, Ebola Virus, CMV and Mycobacterium tuberculosis to facilitate infection. Both DC-SIGN and DC-SIGNR can act either in cis,by concentrating virus on target cells, or in trans, by transmission of bound virus to a target cell expressing appropropriate entry receptors. Recent work showed that DC-SIGN are highaffinity binding receptors for HCV. Besides playing a role in entry into DC, HCV E2 interaction with DC-SIGN might also be detrimental for the interaction of DC with T cells during antigen presentation. The clinical strategies that target DCSIGN may be successful in restricting HCV dissemination and pathogenesis as well as directing the migration of DCs to manipulate appropriate immune responses in autoimmunity and tumorigenic situations.

  5. Reproductive health knowledge among African American women enrolled in a clinic-based randomized controlled trial to reduce psychosocial and behavioral risk, Project DC-HOPE

    Science.gov (United States)

    Backonja, Uba; Robledo, Candace A.; Wallace, Maeve E.; Flores, Katrina F.; Kiely, Michele

    2016-01-01

    Background Washington, D.C. has among the highest rates of sexually transmitted infections (STIs) and unintended pregnancy in the United States. Increasing women’s reproductive health knowledge may help address these reproductive health issues. This analysis assessed whether high-risk pregnant African American women in Washington, D.C. who participated in an intervention to reduce behavioral and psychosocial risks had greater reproductive health knowledge than women receiving usual care. Methods Project DC-HOPE was a randomized controlled trial that included pregnant African American women in Washington, D.C., recruited during prenatal care. Women in the intervention group were provided reproductive health education and received tailored counseling sessions to address their psychosocial and behavioral risk(s) (cigarette smoking, environmental tobacco smoke exposure, depression, and intimate partner violence). Women in the control group received usual prenatal care. Participants completed a 10-item reproductive knowledge assessment at baseline (n=1,044) and postpartum (n=830). Differences in total reproductive health knowledge scores at baseline and postpartum between groups were examined via chi-squared tests. Differences in postpartum mean total score by group were assessed via multiple linear regression. Results Women in both groups and at both time points scored approximately 50% on the knowledge assessments. At postpartum, women in the intervention group had higher total scores compared to women receiving usual care (mean 5.40 [SD 1.60] vs. 5.03 [SD 1.53] out of 10, respectively; p<0.001). Conclusions While intervention participants increased reproductive health knowledge, overall scores remained low. Development of interventions designed to impart accurate, individually tailored information to women may promote reproductive health knowledge among high-risk pregnant African American women residing in Washington, D.C. PMID:27094910

  6. Reproductive Health Knowledge among African American Women Enrolled in a Clinic-Based Randomized Controlled Trial to Reduce Psychosocial and Behavioral Risk: Project DC-HOPE.

    Science.gov (United States)

    Backonja, Uba; Robledo, Candace A; Wallace, Maeve E; Flores, Katrina F; Kiely, Michele

    2016-01-01

    Washington, DC, has among the highest rates of sexually transmitted infections and unintended pregnancy in the United States. Increasing women's reproductive health knowledge may help to address these reproductive health issues. This analysis assessed whether high-risk pregnant African American women in Washington, DC, who participated in an intervention to reduce behavioral and psychosocial risks had greater reproductive health knowledge than women receiving usual care. Project DC-HOPE was a randomized, controlled trial that included pregnant African American women in Washington, DC, recruited during prenatal care (PNC). Women in the intervention group were provided reproductive health education and received tailored counseling sessions to address their psychosocial and behavioral risk(s) (cigarette smoking, environmental tobacco smoke exposure, depression, and intimate partner violence). Women in the control group received usual PNC. Participants completed a 10-item reproductive knowledge assessment at baseline (n = 1,044) and postpartum (n = 830). Differences in total reproductive health knowledge scores at baseline and postpartum between groups were examined via χ(2) tests. Differences in postpartum mean total score by group were assessed via multiple linear regression. Women in both groups and at both time points scored approximately 50% on the knowledge assessments. At postpartum, women in the intervention group had higher total scores compared with women receiving usual care (mean 5.40 [SD 1.60] vs. 5.03 [SD 1.53] out of 10, respectively; p < .001). Although intervention participants increased reproductive health knowledge, overall scores remained low. Development of interventions designed to impart accurate, individually tailored information to women may promote reproductive health knowledge among high-risk pregnant African American women residing in Washington, DC. Published by Elsevier Inc.

  7. Modular Power System Configured with Standard Product Hybrid DC-DC Converters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — VPT proposes an innovative concept whereby complex NASA space power electronic systems can be configured using a small number of qualified hybrid DC-DC converter and...

  8. Improved Control Strategy for T-type Isolated DC/DC Converters

    DEFF Research Database (Denmark)

    Liu, Dong; Deng, Fujin; Wang, Yanbo

    2017-01-01

    T-type isolated DC/DC converters have recently attracted attention due to their numerous advantages, including few components, low cost, and symmetrical operation of transformers. This study proposes an improved control strategy for increasing the efficiency of T-type isolated DC/DC converters....... Under the proposed strategy, the primary circulating current flows through the auxiliary switches (metal–oxide–semiconductor field-effect transistors) instead of their body diodes in free-wheeling periods. Such feature can reduce conduction losses, thereby improving the efficiency of T-type isolated DC....../DC converters. The operation principles and performances of T-type isolated DC/DC converters under the proposed control strategy are analyzed in detail and verified through the simulation and experimental results....

  9. Development of a DC-DC conversion powering scheme for the CMS Phase-1 pixel upgrade

    Science.gov (United States)

    Feld, L.; Fimmers, C.; Karpinski, W.; Klein, K.; Lipinski, M.; Preuten, M.; Rauch, M.; Rittich, D.; Sammet, J.; Wlochal, M.

    2014-01-01

    A novel powering scheme based on the DC-DC conversion technique will be exploited to power the CMS Phase-1 pixel detector. DC-DC buck converters for the CMS pixel project have been developed, based on the AMIS5 ASIC designed by CERN. The powering system of the Phase-1 pixel detector is described and the performance of the converter prototypes is detailed, including power efficiency, stability of the output voltage, shielding, and thermal management. Results from a test of the magnetic field tolerance of the DC-DC converters are reported. System tests with pixel modules using many components of the future pixel barrel system are summarized. Finally first impressions from a pre-series of 200 DC-DC converters are presented.

  10. Wide Temperature Range DC-DC Boost Converters for Command/Control/Drive Electronics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We shall develop wide temperature range DC-DC boost converters that can be fabricated using commercial CMOS foundries. The boost converters will increase the low...

  11. Digitally intensive DC-DC converter for extreme space environments Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Space Micro –Arizona State University (ASU) team will develop an all-digitally controlled, wide temperature range point-of-load switch-mode DC-DC regulator...

  12. DIAGNOSTIC/PROGNOSTIC EXPERIMENTS FOR CAPACITOR DEGRADATION AND HEALTH MONITORING IN DC-DC CONVERTERS

    Data.gov (United States)

    National Aeronautics and Space Administration — Studying and analyzing the ageing mechanisms of electronic components avionics in systems such as the GPS and INAV are of critical importance. In DC-DC power...

  13. Decentralized Nonlinear Controller Based SiC Parallel DC-DC Converter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is aimed at demonstrating the feasibility of a Decentralized Control based SiC Parallel DC-DC Converter Unit (DDCU) with targeted application for...

  14. Development of a DC-DC conversion powering scheme for the CMS Phase-1 pixel upgrade

    CERN Document Server

    Feld, Lutz Werner; Karpinski, Waclaw; Klein, Katja; Lipinski, Martin; Preuten, Marius; Max Rauch; Rittich, David Michael; Sammet, Jan Domenik; Wlochal, Michael

    2014-01-01

    A novel powering scheme based on the DC-DC conversion technique will be exploited to power the CMS Phase-1 pixel detector. DC-DC buck converters for the CMS pixel project have been developed, based on the AMIS5 ASIC designed by CERN. The powering system of the Phase-1 pixel detector is described and the performance of the converter prototypes is detailed, including power efficiency, stability of the output voltage, shielding, and thermal management. Results from a test of the magnetic field tolerance of the DC-DC converters are reported. System tests with pixel modules using many components of the future pixel barrel system are summarized. Finally first impressions from a pre-series of 200 DC-DC converters are presented.

  15. Hybrid-Circuit Module For Dc-To-Dc Power Converter

    Science.gov (United States)

    Vorperian, Vatche; Detwiler, Robert; Karmon, Dan

    1996-01-01

    Power hybrid module is general-purpose power-switching module providing flexibility in design and application. Complete dc-to-dc power converter constructed by adding input/output filters and feedback circuitry to module to suit specific application.

  16. High Efficiency Interleaved Active Clamped Dc-Dc Converter with Fuel Cell for High Voltage Applications

    Directory of Open Access Journals (Sweden)

    Sona P

    2014-02-01

    Full Text Available A high efficiency interleaved ZVS active clamped current fed dc-dc converter is proposed in this paper specially used for fuel cell applications. As the fuel cell output is very low we are in need of a step up dc-dc converter. Here a current fed dc-dc converter is used. Two current fed dc-dc converters are interleaved by connecting their inputs in parallel and outputs in series. With this proposed methodology input current ripples in the fuel cell stacks can be reduced and a regulated output voltage ripples can be obtained. The active clamping circuit used in this model absorbs the turn off voltage spikes hence low voltage devices with low on state resistance can be used.Voltage doubler circuits will give double the output voltage than normal with smaller transformer turns ratio and flexibility. The proposed method is simulated in MATLAB for verifying the accuracy of the proposed design.

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

    Science.gov (United States)

    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.

  18. Digitally intensive DC-DC converter for extreme space environments Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Space Micro-Arizona State University (ASU) team will develop an all-digitally controlled, wide temperature range point-of-load switch-mode DC-DC regulator core...

  19. Studies of Interleaved DC-DC Boost Converters with Coupled Inductors

    Science.gov (United States)

    2011-04-01

    power density requirements, interleaved buck and boost converters have been studied in recent years for their potential to improve power converter ...duty ratio of switch S1. Figure 1: Conventional DC-DC Boost Converter Topology (1) Vout/Vin...interleaved DC-DC boost converters with coupled inductors. Included are discussions on a 10kW prototype, a 2kW high temperature prototype, and two 2kW

  20. A Family of Four Quadrant DC/DC Converters with Reduced Number of Components

    DEFF Research Database (Denmark)

    Mostaan, Ali; Soltani, Mohsen

    2015-01-01

    A family of four quadrant DC/DC converters is presented in this paper. Compare with existing four quadrant DC/DC converters that have been introduced in literature, the proposed converters have lower number of components. There are two bidirectional switches, two coupled inductors and one capacit...... effect is minimized in these converters. The effectiveness of the proposed converters is validated with simulation using MATLAB/SIMULINK....

  1. A Fixed-Frequency Bidirectional Resonant DC-DC Converter Suitable for Wide Voltage Gain Range

    DEFF Research Database (Denmark)

    Shen, Yanfeng; Wang, Huai; Al-Durra, Ahmed;

    2017-01-01

    This paper proposes a new bidirectional resonant dc-dc converter suitable for wide voltage gain range applications (e.g., energy storage systems). The proposed converter overcomes the narrow voltage gain range of conventional resonant DC-DC converters, and meanwhile achieves high efficiency...... and characteristics of the proposed converter are analyzed. Finally, a 1-kW converter prototype is built and the experimental results verify the theoretical analyses....

  2. 多路输出DC-DC电路设计%Design of multiple-output DC-DC circuit

    Institute of Scientific and Technical Information of China (English)

    郑晓庆; 杨日杰; 杨立永; 赵轩坤

    2012-01-01

    In order to convert a single input voltage to multiple outputs,a multiple-output DC-DC conversion circuit based LTC1624 and AMS1117 was designed in this paper. The circuit can convert the input voltage of 12V offered by a lead-acid battery to 5 V,3. 3 V and 1. 8 V as the output,and as tested,the output voltage of the DC-DC circuit designed in this paper is stable and reliable. Supplying power to different modules of a temperature measurement system, the circuit performance meets system requirements.%为了将单一输入电压变换为多路稳压输出,设计了基于LTC1624和AMS1117的DC-DC变换电路,该电路能够将铅酸蓄电池12V输入电压经过DC-DC变换后得到5V、3.3V和1.8V三路输出电压,经测试,设计的DC-DC电路输出电压稳定可靠.该电路应用于某温度测试系统的不同模块供电,电路性能满足系统要求.

  3. Extra-High-Voltage DC-DC Boost Converters Topology with Simple Control Strategy

    Directory of Open Access Journals (Sweden)

    K. Rajambal

    2009-01-01

    Full Text Available This paper presents the topology of operating DC-DC buck converter in boost mode for extra-high-voltage applications. Traditional DC-DC boost converters are used in high-voltage applications, but they are not economical due to the limited output voltage, efficiency and they require two sensors with complex control algorithm. Moreover, due to the effect of parasitic elements the output voltage and power transfer efficiency of DC-DC converters are limited. These limitations are overcome by using the voltage lift technique, opens a good way to improve the performance characteristics of DC-DC converter. The technique is applied to DC-DC converter and a simplified control algorithm in this paper. The performance of the controller is studied for both line and load disturbances. These converters perform positive DC-DC voltage increasing conversion with high power density, high efficiency, low cost in simple structure, small ripples, and wide range of control. Simulation results along theoretical analysis are provided to verify its performance.

  4. Characterization of diode valve in medium voltage dc/dc converter for wind turbines

    DEFF Research Database (Denmark)

    Dincan, Catalin Gabriel; Kjær, Philip Carne

    2016-01-01

    This paper proposes a methodology for characterization of medium voltage (MV), medium frequency (MF) rectifier diode valve. The intended application is for 10MW dc/dc converters used in DC offshore wind turbines. Sensitivity to semiconductor component parameter variation, snubber component...

  5. Analysis of DC/DC Converter Efficiency for Energy Storage System Based on Bidirectional Fuel Cells

    DEFF Research Database (Denmark)

    Pittini, Riccardo; Zhang, Zhe; Andersen, Michael A. E.

    2013-01-01

    Renewable energy sources are fluctuating depending on the availability of the energy source. For this reason, energy storage is becoming more important and bidirectional fuel cells represent an attractive technology. Fuel cells require highcurrent low-voltage dc-dc or dc-ac converters as power...

  6. Startup Capability of Boost DC/DC Converter%Boost DC/DC的低压启动能力

    Institute of Scientific and Technical Information of China (English)

    向乾尹; 冯全源

    2011-01-01

    An analytical model was proposed to calculate the minimum startup voltage of a boost DC/ DC converter under a constant current load. The factors, such as the current load, the parasitic parameters, the saturation current and on-resistance of the power switch, the switching frequency, and the minimum startup voltage, etc. , which affect the startup capability of the boost DC/DC converter were analyzed with a steady-state analysis method. The model was applied to the design of a boost DC/ DC converter with a 0. 6 jxm CMOS process, and the maximum error of the minimum startup voltage calculated by the proposed model was 4. 5% compared with that by the HSPICE simulator.%为了准确预测Boost DC/DC低压启动能力,采用稳态分析方法,分析了电流负载、寄生参数、功率开关饱和电流及导通阻抗、开关频率、启动电路最低工作电压等因素对Boost DC/DC低压启动能力的影响,提出了预测Boost DC/DC恒流负载下最小启动电压的解析模型.将该模型应用于采用0.6 μm CMOS工艺的Boost DC/DC设计中,模型计算结果相对HSPICE仿真结果的最大误差为4.5%.本模型可推广至恒定电阻负载的情况.

  7. Howard University Symposium on Nonlinear Semigroups, Partial Differential Equations and Attractors (2nd) Held in Washington, D. C. on 3-7 August 1987.

    Science.gov (United States)

    1987-09-30

    Building GENERAL INTEREST Chairman: Luis Vazquez, Universidad Complutense , Madrid 8:30 - 9:15 a.m. Robert Sternberg, ONR, Boston "Symmetry in Geometrical... Complutense , Madrid , Spain 70. Andrew Vogt Mathematics Department .C, Georgetown University Washington, D.C. 20057 0- ’-S i!LA! ’ 4& ...University of Madrid B Nicolaenko, Los Alamos National Laboratory W. Strauss. Brown University R. Steinberg, ONR Boston U .IMPORTANT DATES Deadline for

  8. Washington Irving and the American Indian.

    Science.gov (United States)

    Littlefield, Daniel F., Jr.

    1979-01-01

    Some modern scholars feel that Washington Irving vacillated between romanticism and realism in his literary treatment of the American Indian. However, a study of all his works dealing with Indians, placed in context with his non-Indian works, reveals that his attitude towards Indians was intelligent and enlightened for his time. (CM)

  9. Endangered Plants in Oregon and Washington.

    Science.gov (United States)

    Love, Rhoda M.

    1985-01-01

    Presents a partial list of the 132 Oregon and Washington plants which have been proposed for federal protection under the Endangered Species Act. Suggestions for student/citizen involvement in preserving these species and a description of a videotape about rare/endangered species of the Willamette Valley (Oregon) are included. (DH)

  10. Doctors of Osteopathy Licensed in Washington.

    Science.gov (United States)

    Senters, Jo

    Based on information gathered by the Health Manpower Project through a survey cosponsored with the Washington Osteopathic Medical Association, this report begins with a statement of philosophy of osteopathic medicine and proceeds to comment on where such professional education is available. Remarks on the type of educational background of the…

  11. Washington (Wash) C. Winn: In Memoriam

    Centers for Disease Control (CDC) Podcasts

    2012-03-08

    Dr. Mike Miller and Dr. David Walker dicuss the career and life of noted clinical biologist, Dr. Washington C. Winn Jr.  Created: 3/8/2012 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 3/12/2012.

  12. DC/DC converters for integration of double-layer condensers in onboard power supply; DC/DC-Wandler zur Einbindung von Doppelschichtkondensatoren in das Fahrzeugenergiebordnetz

    Energy Technology Data Exchange (ETDEWEB)

    Polenov, Dieter

    2010-01-15

    The paper discusses DC/DC converters for integration of double layer condensers into the onboard power system. First, requirements on DC/DC converters are listed and compared on the basis of three exemplary applications. A DC/DC converter concept is developed for decoupling transient high-power loads like electric steering systems. Three different topologies are compared using a specially developed method in order to find the best solution for the given application. In order to establish adequate criteria for selecting the switching frequency and inductivities of storage throttles, the influence of the trottle power change on the switching characteristics of the MOSFETs and on certain ranges of EMP interference emissions is investigated. As methods of optimising the operation of the synchronous rectifiers, parallel connection of Schottky diodes and synchronous rectifiers as well as the variation of the shut-off dead times of synchronous rectifiers were investigated. Further, a concept for converter control was developed in consideration of the intended application and topology. Finally, selected aspects for implementation of the DC/DC converter concept are presented as well as the results of experimental investigations.

  13. DC KIDS COUNT e-Databook Indicators

    Science.gov (United States)

    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…

  14. DC-based immunotherapy for hematological malignancies.

    Science.gov (United States)

    Kitawaki, Toshio

    2014-02-01

    Great advances have been made in the treatment of hematological malignancies, but achieving a definitive cure remains an elusive goal for the majority of patients. Antigen-specific tumor immunotherapy has the potential to improve clinical outcome in patients with such diseases by eradicating chemotherapy-resistant tumor cell clones without damaging normal tissues. Dendritic cells (DCs) serve as an essential link between the innate and the adaptive immune systems, acting as key controllers of antigen-specific T cell responses. Molecular identification of tumor-specific antigens recognized by T lymphocytes and technical advances in ex vivo generation of human DCs has enabled us to develop DC-based tumor immunotherapies (also called "DC vaccines"). To date, a large number of clinical trials of DC vaccines have been conducted for a variety of tumors, including hematological malignancies. Overall, these trials have demonstrated that DC vaccines have excellent safety profiles, moderate immunological activity, and mild clinical efficacy. To establish a role for DC vaccines in the treatment of hematological malignancies, we need both to define patient populations that can obtain clinical benefit from DC vaccines and to develop combination therapies that augment clinical efficacy of DC vaccines. In this review, I will describe current status of DC-based immunotherapy for hematological malignancies, and discuss future perspectives in this field.

  15. Modelling of flow phenomena during DC casting

    NARCIS (Netherlands)

    Zuidema, J.

    2005-01-01

    Modelling of Flow Phenomena during DC Casting Jan Zuidema The production of aluminium ingots, by semi-continuous casting, is a complex process. DC Casting stands for direct chill casting. During this process liquid aluminium transforms to solid aluminium while cooling down. This is not an instanta

  16. Modelling of flow phenomena during DC casting

    NARCIS (Netherlands)

    Zuidema, J.

    2005-01-01

    Modelling of Flow Phenomena during DC Casting Jan Zuidema The production of aluminium ingots, by semi-continuous casting, is a complex process. DC Casting stands for direct chill casting. During this process liquid aluminium transforms to solid aluminium while cooling down. This is not an

  17. Close-Range Gunfire around DC Schools

    Science.gov (United States)

    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…

  18. Electronic DC transformer with high power density

    NARCIS (Netherlands)

    Pavlovský, M.

    2006-01-01

    This thesis is concerned with the possibilities of increasing the power density of high-power dc-dc converters with galvanic isolation. Three cornerstones for reaching high power densities are identified as: size reduction of passive components, reduction of losses particularly in active components

  19. DC-based magnetic field controller

    Energy Technology Data Exchange (ETDEWEB)

    Kotter, Dale K. (Shelley, ID); Rankin, Richard A. (Ammon, ID); Morgan, John P,. (Idaho Falls, ID)

    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.

  20. DC-based magnetic field controller

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. 75 FR 14462 - Notice of Inventory Completion: Central Washington University, Department of Anthropology...

    Science.gov (United States)

    2010-03-25

    ... Anthropology, Ellensburg, WA, and Thomas Burke Memorial Washington State Museum, University of Washington... of Anthropology, Ellensburg, WA, and the Thomas Burke Memorial Washington State Museum (Burke Museum... Henebry-DeLeon, NAGPRA Program Director, Department of Anthropology, Central Washington...

  2. A Component-Reduced Zero-Voltage Switching Three-Level DC-DC Converter

    DEFF Research Database (Denmark)

    Qin, Zian; Pang, Ying; Wang, Huai;

    2016-01-01

    The basic Zero-Voltage Switching (ZVS) three-level DC-DC converter has one clamping capacitor to realize the ZVS of the switches, and two clamping diodes to clamp the voltage of the clamping capacitor. In order to reduce the reverse recovery loss of the diode as well as its cost, this paper...... proposes to remove one of the clamping diodes in basic ZVS three-level DC-DC converter. With less components, the proposed converter can still have a stable clamping capacitor voltage, which is clamped at half of the dc link voltage. Moreover, the ZVS performance will be influenced by removing the clamping...

  3. Key Facts about Higher Education in Washington. 2012

    Science.gov (United States)

    Washington Higher Education Coordinating Board, 2012

    2012-01-01

    "Key Facts about Higher Education in Washington" provides vital data to chart higher education's progress and challenges. First published in 2002 by the Washington Higher Education Coordinating Board, this annual report highlights "Key Facts" about Washington's postsecondary institutions--including faculty, students,…

  4. 33 CFR 117.1051 - Lake Washington Ship Canal.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lake Washington Ship Canal. 117.1051 Section 117.1051 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Washington § 117.1051 Lake Washington Ship Canal. (a) When fog prevails by day or...

  5. 7 CFR 923.322 - Washington cherry handling regulation.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Washington cherry handling regulation. 923.322 Section... CHERRIES GROWN IN DESIGNATED COUNTIES IN WASHINGTON Order Regulating Handling Grade, Size, Container and Pack Regulation § 923.322 Washington cherry handling regulation. (a) Grade. No handler shall...

  6. 76 FR 16323 - Irish Potatoes Grown in Washington; Continuance Referendum

    Science.gov (United States)

    2011-03-23

    ... Agricultural Marketing Service 7 CFR Part 946 Irish Potatoes Grown in Washington; Continuance Referendum AGENCY... referendum be conducted among eligible Washington potato growers to determine whether they favor continuance of the marketing order regulating the handling of Irish potatoes grown in Washington. DATES: The...

  7. Controlling DC-DC converters by chaos-based pulse width modulation to reduce EMI

    Energy Technology Data Exchange (ETDEWEB)

    Li Hong [Department of Mathematics and Computer Science, FernUniversitaet in Hagen, 58084 Hagen (Germany)], E-mail: hong.li@FernUni-Hagen.de; Zhang Bo [School of Electric Power, South China University of Technology, Guangzhou (China); Li Zhong; Halang, Wolfgang A. [Department of Mathematics and Computer Science, FernUniversitaet in Hagen, 58084 Hagen (Germany); Chen Guanrong [Department of Electronic Engineering, City University of Hong Kong, Hong Kong (China)

    2009-11-15

    In this paper, periodic and chaotic behaviors of DC-DC converters under certain parametric conditions are simulated, experimentally verified, and analyzed. Motivated by the work of J.H.B. Deane and D.C. Hamill in 1996, where chaotic phenomena are useful in suppressing electromagnetic interference (EMI) by adjusting the parameters of the DC-DC converter and making it operate in chaos, a chaos-based pulse width modulation (CPWM) is proposed to distribute the harmonics of the DC-DC converters continuously and evenly over a wide frequency range, thereby reducing the EMI. The output waves and spectral properties of the EMI are simulated and analyzed as the carrier frequency or amplitude changes with regard to different chaotic maps. Simulation and experimental results are given to illustrate the effectiveness of the proposed CPWM, which provides a good example of applying chaos theory in engineering practice.

  8. Voltage Tracking of a DC-DC Flyback Converter Using Neural Network Control

    Directory of Open Access Journals (Sweden)

    Wahyu Mulyo Utomo

    2012-01-01

    Full Text Available This paper proposes a neural network control scheme of a DC-DC Flyback converter that will step up a 12V DC and applied it on brushless DC motor with 12 and 24V dc. In this technique, a back propagation learning algorithm is derived. The controller is designed to track the output voltage of the DC-DC converter and to improve performance of the Flyback converter during transient operations. Furthermore, to investigate the effectiveness of the proposed controller, some operations such as starting-up and reference voltage variations are verified. The numerical simulation results show that the proposed controller has a better performance compare to the conventional PI-Controller method.

  9. High Current Planar Magnetics for High Efficiency Bidirectional DC-DC Converters for Fuel Cell Applications

    DEFF Research Database (Denmark)

    Pittini, Riccardo; Zhang, Zhe; Andersen, Michael A. E.

    2014-01-01

    Efficiency is one of the main concerns during the design phase of switch mode power supply. Planar magnetics based on PCB windings have the potential to reduce the magnetic manufacturing cost however, one of their main drawbacks comes from their low filling factor and high stray capacitance....... This paper presents an analysis of different planar windings configurations focusing on dc and ac resistances in order to achieve highly efficiency in dc-dc converters. The analysis considers different copper thicknesses form 70 μm up to 1500 μm (extreme copper PCB) taking into account manufacturing...... complexity and challenges. The analysis is focused on a high current inductor for a dc-dc converter for fuel cell applications and it is based on FEM simulations. Analysis and results are verified on a 6 kW dc-dc isolated full bridge boost converter prototype based on fully planar magnetics achieving a peak...

  10. A high voltage ratio and low ripple interleaved DC-DC converter for fuel cell applications.

    Science.gov (United States)

    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.

  11. Theory of multi-phase PWM DC/DC converter%多相PWM控制DC/DC变换器

    Institute of Scientific and Technical Information of China (English)

    陈小明

    2001-01-01

    @@ 概述 近年来,随着一些高性能CPU的出现,如Pentium 4、Athlon等,需要输出电压更小,更大电流的DC/DC变换器,对热性能、EMI及负载瞬变应答(Load Transient)的要求也不断提高.传统的单相DC/DC变换器日益显示出局限性.多相DC/DC变换器以其独特的性能,为高性能CPU电源的解决方案开辟的一条新路.

  12. Swarming Speed Control for DC Permanent Magnet Motor Drive via Pulse Width Modulation Technique and DC/DC Converter

    Directory of Open Access Journals (Sweden)

    A.S. Oshaba

    2013-05-01

    Full Text Available This study presents an approach for the speed control of a permanent magnet DC motor drive via Pulse Width Modulation (PWM technique and a DC/DC converter. The Particle Swarm Optimization (PSO technique is used to minimize a time domain objective function and obtain the optimal controller parameters. The performance of the proposed technique has been evaluated using various types of disturbances including load torque variations. Simulation results illustrate clearly the robustness of the controller and validity of the design technique for controlling the speed of permanent magnet motors.

  13. DC/DC开关变换器混沌现象研究综述%Summary of the Research on Chaos Phenomena of DC/DC Converter

    Institute of Scientific and Technical Information of China (English)

    蔚洋; 冯平

    2012-01-01

    DC/DC功率开关变换器是开关电源的核心部分,通过对其混沌现象的研究可以更加深刻地认识DC/DC变换器的本质,也会在将来基于混沌现象提出新的设计方法和控制策略,实现现有DC/DC变换器无法达到的性能.本文介绍了DC/DC变换器混沌现象的研究现状,对DC/DC变换器混沌现象的基本建模方法进行了综合对比分析,展望了DC/DC变换器混沌研究的发展和未来应用前景.%DC/DC power switch converter is the core part of switch power supply. Through the study of chaos phenomena, the essence of DC/DC converter can be more deeply understand, the new design methods and control strategies based on chaos phenomena will be put forward in the future, to achieve the existing DC/DC converter that cannot reach. This paper introduces the research status of the DC/DC converter chaos phenomena, makes comprehensive comparative analysis of the basic modeling method of DC/DC converter chaos phenomena, and looks to its development and future application prospect.

  14. Pulsed-DC DBD Plasma Actuators

    Science.gov (United States)

    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.

  15. Control and dynamic analysis of a parallel-connected single active bridge DC-DC converter for DC-grid wind farm application

    DEFF Research Database (Denmark)

    Park, Kiwoo; Chen, Zhe

    2015-01-01

    This study presents a control strategy and its dynamic analysis of a high-power dc-dc converter, which is constructed with the parallel-connected single active bridge (SAB) dc-dc converters for dc-grid wind farm applications. The structural and operational characteristics of the SAB dc-dc converter...... have several advantages for high-power applications, and the modular concept of the parallel-connected converter is highly beneficial especially for offshore wind farm applications in terms of maintenance cost and fault tolerance. To justify the feasibility of the parallel-connected SAB dc-dc converter...... for dc-grid wind farm applications, an input voltage control method based on the PI control will be introduced and the dynamics of the overall system will be analysed. The analysis results are to be verified by means of simulations and experiments....

  16. Expression of DC-SIGN and DC-SIGNRs in placentas of HIV-positive patients

    Directory of Open Access Journals (Sweden)

    Komala Pillay

    2014-09-01

    Full Text Available Background. Human dendritic cell-specific intracellular adhesion molecule-3 (ICAM3-grabbing non-integrin (DC-SIGN is a mannose-binding lectin that initiates interaction between dendritic cells and resting T-lymphocytes. DC-SIGN is highly expressed in placental tissue on dendritic cells and Hofbauer cells, and it is suggested that HIV may become adsorbed to DC-SIGN on Hofbauer cells as part of the mechanism of mother-to-child HIV transmission. A possible mechanism of transfer of the virus from the Hofbauer cells to the fetus is the subsequent adsorption to DC-SIGN-related molecules (DC-SIGNRs, present on immediately adjacent capillary vascular endothelium. However, data on DC-SIGN and DC-SIGNR expression in the placenta are few.Methods. Forty term placentas from HIV-positive mothers and 21 term placentas from HIV-negative mothers underwent immunohistochemistry staining for DC-SIGN and DC-SIGNR expression. Five random sets of 10 villi were assessed, and the average number of positive cells were counted in each case. In addition, where possible, maternal and cord blood viral loads and maternal CD4+ counts were performed in the HIV-positive group only.Results. The median maternal CD4+ count was 377 cells/µl and 27% of participants had undetectable viral loads; the median detectable viral load was 3.72 log. Most (97% of the cord bloods tested in infants from HIV-positive mothers had lower than detectable viral loads. HIV-positive cases had significantly greater expression of both DC-SIGNRs (median values in HIV-positive cases, 14.5 positive cells/10 villi (pc/10villi, compared with 11 pc/10villi in HIV-negative cases, p=0.020 and DC-SIGN (median value in HIV-positive cases, 26.5 pc/10villi, compared with 23 pc/10villi in HIV-negative cases, p=0.037. DC-SIGNR expression was also noted in Hofbauer cells and decidual macrophages in addition to endothelium (reported currently. There was no difference in expression of DC-SIGN and DC-SIGNRs in patients

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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. Studi Komparasi Fungsi Keanggotaan Fuzzy sebagai Kontroler Bidirectional DC-DC Converter pada Sistem Penyimpan Energi

    Directory of Open Access Journals (Sweden)

    Eka Prasetyono

    2015-09-01

    Full Text Available Bidirectional DC-DC converter is needed in the energy storage system. The converter topology used in this paper was a non-isolated bidirectional DC-DC buck-boost converter. This converter worked in two ways, which the charging mode stored energy into battery when load current was less than nominal main DC current (set point and discharging mode transferred energy from battery to the load when its current exceeded set point value. Both of these modes worked automatically according to the load current. The charging and discharging currents were controlled by fuzzy logic controller which was implemented on microcontroller ARM Cortex-M4F STM32F407VG. This paper compares two types of fuzzy membership function (triangular and sigmoid in controlling bidirectional DC-DC converter. The results showed that fuzzy logic controller with triangle membership function and sigmoid as control bidirectional DC-DC converter had no significant different response, both had an average error for charging and discharging process under 4% with ripple current on the main DC bus around 0.5%. The computing time of program for fuzzy logic controller with triangular membership functions had 19.01% faster than sigmoid, and fuzzy logic computation time on a microcontroller with hardware floating point was 60% faster than software floating point.

  1. Study on the Control Algorithm of Two-Stage DC-DC Converter for Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Changhao Piao

    2014-01-01

    Full Text Available The fast response, high efficiency, and good reliability are very important characteristics to electric vehicles (EVs dc/dc converters. Two-stage dc-dc converter is a kind of dc-dc topologies that can offer those characteristics to EVs. Presently, nonlinear control is an active area of research in the field of the control algorithm of dc-dc converters. However, very few papers research on two-stage converter for EVs. In this paper, a fixed switching frequency sliding mode (FSFSM controller and double-integral sliding mode (DISM controller for two-stage dc-dc converter are proposed. And a conventional linear control (lag is chosen as the comparison. The performances of the proposed FSFSM controller are compared with those obtained by the lag controller. In consequence, the satisfactory simulation and experiment results show that the FSFSM controller is capable of offering good large-signal operations with fast dynamical responses to the converter. At last, some other simulation results are presented to prove that the DISM controller is a promising method for the converter to eliminate the steady-state error.

  2. Superconducting DC homopolar motors for ship propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Heiberger, M.; Reed, M.R.; Creedon, W.P.; O' Hea, B.J. [General Atomic (United States)

    2000-07-01

    Superconducting DC homopolar motors have undergone recent advances in technology, warranting serious consideration of their use for ship propulsion. Homopolar motor propulsion is now practical because of two key technology developments: cryogen-free superconducting refrigeration and high performance motor fiber brushes. These compact motors are ideal for podded applications, where reduced drag and fuel consumption are predicted. In addition, the simple DC motor controller is more efficient and reliable compared with AC motor controllers. Military ships also benefit from increased stealth implicit in homopolar DC excitation, which also allows the option for direct hull or pod mounting. (authors)

  3. DC-Compensated Current Transformer †

    Science.gov (United States)

    Ripka, Pavel; Draxler, Karel; Styblíková, Renata

    2016-01-01

    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. PMID:26805830

  4. A series array of dc SQUIDs

    Energy Technology Data Exchange (ETDEWEB)

    Welty, R.P. (Colorado Univ., Boulder, CO (United States). Dept. of Electrical Engineering); Martinis, J.M. (Geraghty and Miller, Inc., Reston, VA (United States))

    1991-03-01

    This paper reports on a series array of 100 dc SQUIDs using trilayer Nb-AlO{sub x}-Nb junctions. The SQUIDs are modulated with a common flux bias line and produce an output voltage swing of several millivolts across the array. The large output voltage will allow direct connection to room temperature electronics without the transformer coupling and resulting frequency limitations commonly associated with dc SQUID amplifiers. The authors measured a bandwidth of dc to at least 175 MHz for a 100-SQUID array. The series array will be used as the output stage for a multistage integrated SQUID amplifier.

  5. Low-temperature geothermal resources of Washington

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, J.E. [Washington State Dept. of Natural Resources, Olympia, WA (United States). Div. of Geology and Earth Resources; Bloomquist, R.G. [Washington State Energy Office, Olympia, WA (United States)

    1994-06-01

    This report presents information on the location, physical characteristics, and water chemistry of low-temperature geothermal resources in Washington. The database includes 941 thermal (>20C or 68F) wells, 34 thermal springs, lakes, and fumaroles, and 238 chemical analyses. Most thermal springs occur in the Cascade Range, and many are associated with stratovolcanoes. In contrast, 97 percent of thermal wells are located in the Columbia Basin of southeastern Washington. Some 83.5 percent are located in Adams, Benton, Franklin, Grant, Walla Walla, and Yakima Counties. Yakima County, with 259 thermal wells, has the most. Thermal wells do not seem to owe their origin to local sources of heat, such as cooling magma in the Earth`s upper crust, but to moderate to deep circulation of ground water in extensive aquifers of the Columbia River Basalt Group and interflow sedimentary deposits, under the influence of a moderately elevated (41C/km) average geothermal gradient.

  6. Constant switching frequency control-based linear-assisted DC/DC regulator for photovoltaic solar-powered facilities

    OpenAIRE

    Martínez García, Herminio; Grau Saldes, Antoni

    2015-01-01

    Hybrid DC-DC regulators or linear–assisted DC-DC regulators are structures that combine both a linear voltage regulator and a switching DC-DC converter. The main objective of this hybrid topology is to converge, in a single circuit topology, the best of both alternatives: One the one hand, obtaining small voltage output ripple, which is typical of linear regulator structures, and, on the other, achieving good energy efficiency, as in switching alternatives. While the linear regulator fixes th...

  7. LLC resonant half-bridge circuit design with DC-DC%LLC谐振半桥DC-DC电路设计

    Institute of Scientific and Technical Information of China (English)

    杨磊; 吴晓光; 羊彦

    2013-01-01

    LED drive power level after the DC-DC constant current circuit using LLC resonant half-bridge topology structure, and through the output current and voltage feedback loop to achieve constant current limiting function.LLC resonant half-bridge DC-DC constant current circuit power part comprises a resonant circuit and the output of the rectifier circuit, the control part chip power supply circuit, the control chip peripheral circuit, an output feedback loop, the test shows that the system has stable output can be good, long time working with high efficiency.%LED驱动电源的后级DC-DC恒流电路采用LLC谐振半桥的拓扑结构,并通过输出的电流电压双环反馈来实现恒流限压功能.LLC谐振半桥DC-DC恒流电路的功率部分包括了谐振电路和输出整流电路,控制部分有芯片供电电路、控制芯片外围电路、输出反馈回路等,经试验证明该系统输出稳定好,能够长时间高效工作.

  8. Determination of input/output characteristics of full-bridge AC/DC/DC converter for arc welding

    OpenAIRE

    Stefanov, Goce; Karadzinov, Ljupco; Sarac, Vasilija; Cingoski, Vlatko; Gelev, Saso

    2016-01-01

    This paper describes the design and practical implementation of AC/DC/DC converter in mode of arc welding. An analysis of the operation of AC/DC/DC converter and its input/output characteristics are determined with computer simulations. The practical part is consisted of AC/DC/DC converter prototype for arc welding with output power of 3 kW and switching frequency of 64 kHz. The operation of AC/DC/DC converter is validated with experimental measurements.

  9. (PFC) converters feeding brushless DC motor drive

    African Journals Online (AJOL)

    DR OKE

    harmonic distortion (THD) of supply current at AC mains for a wide range of ... An uncontrolled diode bridge rectifier (DBR) with high value of DC link ...... ac transmission systems), HVDC (High voltage direct current) transmission systems. Prof.

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

    Science.gov (United States)

    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.

  11. DC-DC Conversion Powering Schemes for the CMS Tracker at Super-LHC

    CERN Document Server

    Klein, Katja; Jussen, Rüdiger; Karpinski, Waclaw; Merz, Jennifer; Sammet, Jan

    2010-01-01

    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 th...

  12. The DC-DC conversion power system of the CMS Phase-1 pixel upgrade

    Science.gov (United States)

    Feld, L.; Karpinski, W.; Klein, K.; Lipinski, M.; Preuten, M.; Rauch, M.; Schmitz, St.; Wlochal, M.

    2015-01-01

    The pixel detector of the CMS experiment will be exchanged during the year-end technical stop in 2016/2017, as part of the experiment's Phase-1 upgrade. The new device will feature approximately twice the number of readout channels, and consequently the power consumption will be doubled. By moving to a DC-DC conversion powering scheme, it is possible to power the new pixel detector with the existing power supplies and cable plant. The power system of the Phase-1 pixel detector is described and the performance of the new components, including DC-DC converters, DC-DC converter motherboards and various power distribution boards, is detailed. The outcome of system tests in terms of electrical behaviour, thermal management and pixel module performance is discussed.

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

    Science.gov (United States)

    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 %).

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

    Science.gov (United States)

    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.

  15. Efficient and ripple-mitigating dc-dc converter for residential fuel cell system

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yong [Danfoss Solar Inverters, Hardware, Jyllandsgade 28, 6400 Soenderborg (Denmark); Choi, Seeyoung [Digital Appliance Division, Samsung Electronics Co. Ltd., Maetan-3Dong, Suwon, Gyeonggi (Korea); Lee, Eunchul [Willings Co. Ltd., SK Ventium, 522 Dangjung-Dong, Gunpo-Si, Gyeonggi-Do (Korea)

    2009-01-15

    Proton exchange membrane fuel cell (PEMFC) systems for residential application require efficient and ripple-mitigating power conditioning system (PCS). The key point to reach it, is the design and control of the dc-dc converter. Based on the theoretical and experimental analysis of the traditional converter, this paper proposes a novel parallel-series full bridge (P-SFB) dc-dc converter, and improves its phase shifting scheme. This paper also proposes a novel controller for low frequency ripple current suppressing applied on the converter. The experimental results verify that, the dc-dc converter achieves a peak efficiency of 95.5%. Therefore PCS's maximum efficiency reaches 92.9%. And the input current ripple is reduced significantly with the new controller. (author)

  16. Critical conditions of saddle-node bifurcations in switching DC-DC converters

    Science.gov (United States)

    Fang, Chung-Chieh

    2013-08-01

    Although existence of multiple periodic orbits in some DC-DC converters have been known for decades, linking the multiple periodic orbits with the saddle-node bifurcation (SNB) is rarely reported. The SNB occurs in popular DC-DC converters, but it is generally reported as a strange instability. Recently, design-oriented instability critical conditions are of great interest. In this article, average, sampled-data and harmonic balance analyses are applied and they lead to equivalent results. Many new critical conditions are derived. They facilitate future research on the instability associated with multiple periodic orbits, sudden voltage jumps or disappearances of periodic orbits observed in DC-DC converters. The effects of various converter parameters on the instability can be readily seen from the derived critical conditions. New Nyquist-like plots are also proposed to predict or prevent the occurrence of the instability.

  17. Simulation and Implementation of Interleaved Boost DC-DC Converter for Fuel Cell Application

    Directory of Open Access Journals (Sweden)

    Ahmad Saudi Samosir

    2011-10-01

    Full Text Available This paper deals with a boost dc-dc converter for fuel cell application. In fuel cell electric vehicles application, a high power boost dc-dc converter is adopted to adjust the output voltage, current and power of fuel cell engine to meet the vehicle requirements. One of challenge in designing a boost converter for high power application is how to handle the high current at the input side. In this paper an interleaved boost dc-dc converter is proposed for current sharing on high power application. Moreover, this converter also reduces the fuel ripple current. Performance of the interleaved boost converter is tested through simulation and experimental results. Keywords: component; Interleaved Boost Converter; Fuel Cell Electric Vehicle; high power application.  

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

    Science.gov (United States)

    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.

  19. Optimized photovoltaic generator-water electrolyser coupling through a controlled DC-DC converter

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Valverde, R.; Miguel, C.; Urbina, A. [Universidad Politecnica de Cartagena, Departamento de Electronica, Tecnologia de Computadoras y Proyectos, Plaza del Hospital, 1, Cartagena, 30203 Murcia (Spain); Martinez-Bejar, R. [Universidad de Murcia, Departamento de Ingenieria de la Informacion y las Comunicaciones, Facultad de Informatica, Campus de Espinardo, 30071 Murcia (Spain)

    2008-10-15

    The coupling of a photovoltaic generator and an electrolyser is one of the most promising options for obtaining hydrogen from a renewable energy source. Both are well known technologies, however, since the high variability of the solar radiation, an efficient coupling still presents some challenges. Direct or through a DC-DC converter couplings are the options in isolated applications. In this work, three models, respectively, for a photovoltaic (PV) generator, a controlled DC-DC converter and a complete proton exchange membrane (PEM) electrolyser have been designed by using Matlab/Simulink. A PV-electrolyser specific algorithm to search for the optimum and safe working point for both elements is presented. Simulation results demonstrate that the use of a controlled DC-DC converter with the proposed algorithm shows better adaptability to the variable radiation conditions than the other coupling options. Therefore, it leads to a better compliance between the electrolyser and the sizing of the PV generator. (author)

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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. Ultra-high Efficiency DC-DC Converter using GaN Devices

    DEFF Research Database (Denmark)

    Ramachandran, Rakesh

    2016-01-01

    The demands for high efficiency dc-dc power converters are increasing day by day in various applications such as telecommunication, data-centers, electric vehicles and various renewable energy systems. Silicon (Si) has been used as the semiconductor material in majority of the power devices...... properties of GaN devices can be utilized in power converters to make them more compact and highly efficient. This thesis entitled “Ultra-high Efficiency DC-DC Converter using GaN devices” focuses on achieving ultra-high conversion efficiency in an isolated dc-dc converter by the optimal utilization of Ga......N devices. Simple replacement of Si or SiC devices with GaN devices in the converter will not give an expected increase in efficiency or any improvement in the performance of the converter. The use of GaN devices has defined another dimension in the design of power converters, which mainly deals...

  3. Efficiency Enhancement of DC to DC Multilevel Boost Converter and Its Applications

    Directory of Open Access Journals (Sweden)

    R. Ravikumar

    2015-03-01

    Full Text Available The aim of this study is to propose a experimental verification for single-phase to three phase drive system composed of two parallel single-phase rectifiers, a three-phase inverter and an induction motor. Apart from traditional application in dc motor drives, new applications of BDC include energy storage in renewable energy systems, fuel cell energy systems, Hybrid Electric Vehicles (HEV and Uninterruptible Power Supplies (UPS. A dc-dc converter is always required to allow energy exchange between storage device and the rest of system. In HEV applications, BDCs are required to link different dc voltage buses and transfer energy between them. A non-isolated bi-directional dc-dc converters is used in our project to achieve better efficiency.

  4. The DC-DC converter reduces its size and increases its efficiency; Le convertisseur DC-DC reduit sa taille et augmente son rendement

    Energy Technology Data Exchange (ETDEWEB)

    Feste, J.P.

    2000-03-01

    The DC to DC converters built by the US SynQor company use a dual stage conversion technique. One stage is devoted to regulation and the other to insulation. This technique allows to combine a high efficiency (up to 90%) with small dimensions. Instead of the classical Schottky diodes, a synchronous MOSFET is used for the rectification of the low voltage current. A simple air flow is required for the cooling of these converters. Short paper. (J.S.)

  5. Solid-State dc Circuit Breaker

    Science.gov (United States)

    Harvey, P.

    1983-01-01

    Circuit breaker with no moving parts protects direct-current (dc) loads. Current which circuit breaker opens (trip current) is adjustable and so is time delay before breaker trips. Forward voltage drop rises from 0.6 to 1.2 V as current rises to trip point. Breaker has two terminals, like fuse, therefore replaces fuse in dc circuit. Powered by circuit it protects and reset by either turning off power source or disconnecting load.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  8. Model predictive control of bidirectional isolated DC-DC converter for energy conversion system

    Science.gov (United States)

    Akter, Parvez; Uddin, Muslem; Mekhilef, Saad; Tan, Nadia Mei Lin; Akagi, Hirofumi

    2015-08-01

    Model predictive control (MPC) is a powerful and emerging control algorithm in the field of power converters and energy conversion systems. This paper proposes a model predictive algorithm to control the power flow between the high-voltage and low-voltage DC buses of a bidirectional isolated full-bridge DC-DC converter. The predictive control algorithm utilises the discrete nature of the power converters and predicts the future nature of the system, which are compared with the references to calculate the cost function. The switching state that minimises the cost function is selected for firing the converter in the next sampling time period. The proposed MPC bidirectional DC-DC converter is simulated with MATLAB/Simulink and further verified with a 2.5 kW experimental configuration. Both the simulation and experimental results confirm that the proposed MPC algorithm of the DC-DC converter reduces reactive power by avoiding the phase shift between primary and secondary sides of the high-frequency transformer and allow power transfer with unity power factor. Finally, an efficiency comparison is performed between the MPC and dual-phase-shift-based pulse-width modulation controlled DC-DC converter which ensures the effectiveness of the MPC controller.

  9. Design of the DC-DC power stage of the capacitor charger for MAXIDISCAP power converters

    CERN Document Server

    Cravero, Jean-Marc

    2013-01-01

    This technical report presents the design of the DC-DC power stage of the capacitor charger for MAXIDISCAP power converters. The power stage is based on a half bridge series resonant converter in Discontinuous Conduction Mode (DCM). This simple and robust topology allows obtaining a current source behavior with a low switching losses power stage. The associated control stage is implemented using a commercial controller which has differenti nternal circuits that allows a high integration of the converter control system. The report presents the design and tuning criteria for the DC-DC converter, including the power stage and the control system.

  10. A Reduced-Part, Triple-Voltage DC-DC Converter for Electric Vehicle Power Management

    Energy Technology Data Exchange (ETDEWEB)

    Su, Gui-Jia [ORNL; Tang, Lixin [ORNL

    2007-01-01

    Electrical power systems in future hybrid and fuel cell vehicles may consist of three voltage nets; 14 V, 42 V and high voltage (>200 V) buses. A soft-switched, bi-directional dc-dc converter using only four switches was proposed for interconnecting the three nets. This paper presents a reduced- part dc-dc converter, which decreases the converter cost while retaining all the favorable features of the original topology. Simulation and experimental data are included to verify a simple power flow control scheme.

  11. High-Voltage DC-DC Converter Topology for PV Energy Utilization - Investigation and Implementation

    DEFF Research Database (Denmark)

    Sanjeevikumar, Padmanaban; Blaabjerg, Frede; Wheeler, Patrick

    2017-01-01

    This paper exploited the utilization of photovoltaic (PV) energy system with high-voltage (HV) output DC-DC converter. Classical boost converters are used for both renewable energy integration and HV applications, but limited by reducing output/efficiency in performance. Moreover, as parasitic...... elements suppress the power transfer ratio, converter needs to maximize the PV energy utilization. This investigation study focused to include additional parasitic elements (voltage-lift technique) to a standard DC-DC buck converter and to overcome all the above drawbacks to maximize the PV power...

  12. Laboratory manual for pulse-width modulated DC-DC power converters

    CERN Document Server

    Kazimierczuk, Marian K

    2015-01-01

    Designed to complement a range of power electronics study resources, this unique lab manual helps students to gain a deep understanding of the operation, modeling, analysis, design, and performance of pulse-width modulated (PWM) DC-DC power converters.  Exercises focus on three essential areas of power electronics: open-loop power stages; small-signal modeling, design of feedback loops and PWM DC-DC converter control schemes; and semiconductor devices such as silicon, silicon carbide and gallium nitride. Meeting the standards required by industrial employers, the lab manual combines program

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Kroics K.

    2016-08-01

    Full Text Available 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.

  18. REFORMASI EKONOMI, KONSENSUS WASHINGTON, DAN RINTANGAN POLITIK

    Directory of Open Access Journals (Sweden)

    Ahmad Erani Yustika

    2004-01-01

    Full Text Available In the practice of policy reform, the new thinking in development theorizing found its expression in the formulation of the so-called Washington Consensus. Triggered by widespread government failures, the Washington Consensus is based on stabilization-cum-adjustment policies recommended by the Bretton Woods organizations and US economic officials. It emphasizes the need for prudent macroeconomic and financial policies, unified and competitive exchange rates, trade and financial liberalization, privatization, and deregulation. However, because of neglecting political domain, the running of economic reform resulted a deeper economic crisis. Beside, in the implementation phase, economic reform process often meet political barriers. At least three political barriers often fail economic reform program. First, collective action problems arise to the extent that economic reforms have the properties of a public good, either for the society as a whole or for a large number of potential beneficiaries. Second, In a distributive model, policy reform is supported by winners and opposed by losers, and the outcome is given by the balance of political power between the respective action. Third, one classic problem with many reforms is that the costs of reform tend to be concentrated, while benefits are diffuse, producing perverse organizational incentives (Haggard dan Kaufman, 1995:156-157. Argentina and Mexico cases show that economic reform can failure due to polical barriers. Abstract in Bahasa Indonesia : Dalam pelaksanaan kebijakan reformasi, teori pembangunan mutakhir telah menemukan konsep baru yang diformulasikan dalam istilah yang biasa disebut dengan Konsensus Washington. Dipicu oleh kegagalan pemerintah yang semakin meluas dalam mengelola kegiatan ekonomi, konsep Konsensus Washington berpijak pada upaya stabilisasi melalui kebijakan penyesuaian struktural, yang direkomendasikan oleh organisasi Bretton Woods dan Badan Ekonomi Amerika Serikat

  19. DC KIDS COUNT e-Databook

    Science.gov (United States)

    DC Action for Children, 2012

    2012-01-01

    Every city has many identities, depending on who one asks. A legislator, a police officer, a coach or a clerk might describe the same city's people, culture and reputation in starkly different terms. Washington, the nation's capital, is an international center of power, featuring stately embassies and serving as the temporary home to diplomats.…

  20. Design of current source DC/DC converter and inverter for 2kW fuel cell application

    DEFF Research Database (Denmark)

    Andreiciks, A.; Steiks, I.; Krievs, O.

    2013-01-01

    of a DC/DC converter and an inverter. In this paper a detailed simulation study of such interfacing converter system comprising a double inductor push-pull step-up DC/DC converter and a cascaded H-bridge inverter has been carried out and further confirmed with experimental results. The power converter...