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Sample records for research washington dc

  1. 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.

  2. Trends and determinants of cycling in the Washington, DC region.

    Science.gov (United States)

    2011-01-01

    This report analyzes cycling trends, policies, and commuting in the Washington, DC area. The analysis is divided into two parts. : Part 1 focuses on cycling trends and policies in Washington (DC), Alexandria (VA), Arlington County (VA), Fairfax Count...

  3. The hydrogeology of urbanization: The lost springs of Washington, D.C., late Tertiary and Quaternary sediments of D.C., and the Baltimore Long Term Ecological Research site (LTER): Chapter

    Science.gov (United States)

    Bhaskar, Aditi; Pavich, Milan J.; Sharp, John M.

    2015-01-01

    Urbanization is a major process now shaping the environment. This field trip looks at the hydrogeology of the general Washington, D.C., area and focuses on the city's lost springs. Until 150 years ago, springs and shallow dug wells were the main source of drinking water for residents of Washington, D.C. Celebrating the nation's bicentennial, Garnett P. Williams of the U.S. Geological Survey examined changes in water supply and water courses since 1776. He examined old newspaper files to determine the location of the city's springs. This field trip visits sites of some of these springs (few of which are now flowing), discusses the hydrologic impacts of urbanization and the general geological setting, and finishes with the Baltimore Long Term Ecological Research site at Dead Run and its findings. The field trip visits some familiar locations in the Washington, D.C., area, and gives insights into their often hidden hydrologic past and present.

  4. 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

  5. Early Restoration Public Meeting, Washington, DC | NOAA Gulf Spill

    Science.gov (United States)

    benefit injured marshes, coastal dune and nearshore habitats, oysters, and human uses (on water recreation . Department of Commerce Herbert Hoover Building Auditorium 1401 Constitution Ave., NW Washington, D.C. 20230

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

    International Nuclear Information System (INIS)

    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

  7. Report of the Annual Scientific Sessions of the American College of Cardiology (ACC), Washington DC.

    Science.gov (United States)

    Hiro, Takafumi

    2017-05-25

    The 66 th Annual Scientific Sessions and Expo of the American College of Cardiology (ACC) were held at the Walter E. Washington Convention Center, Washington DC, from March 17 th to 19 th , 2017. This meeting offered 23 Late-Breaking Clinical Trial (LBCT) presentations, 17 Featured Clinical Research presentations with and without LBCT, and 2,572 abstracts presented in oral and poster sessions by over 2,000 experts. This report presents the highlights of this meeting, including the opening showcase, several important LBCTs and some international joint symposiums.

  8. Effects of the 2002 sniper attacks on the homeless population in Washington, DC.

    Science.gov (United States)

    Fullerton, Carol S; Gifford, Robert K; Flynn, Brian W; Peterson, Karen M; Ahearn, Frederick L; Donaldson, Linda Plitt; Ursano, Robert J

    2009-10-01

    Despite the prevalence of homelessness, this population has rarely been included in disaster and terrorism planning. To better understand the mental health needs of the homeless during a terrorist event and to highlight the need to address methodological limitations in research in this area, we examined responses to the October 2002 Washington, DC, sniper attacks. We interviewed 151 homeless individuals 1 year after the Washington, DC, sniper attacks. The majority (92.7%) was aware of the sniper events; 84.1% stayed informed through the media and 72.7% had someone to turn to for emotional support. Almost half (44%) reported identification with victims and 41% increased substance use during the attacks. More than half (61.7%) felt extremely frightened or terrified and 57.6% reported high perceived threat. Females, nonwhites, and participants with less than a high school education experienced greater threat. Women, nonwhites, and younger (homeless population may be difficult to reach or reluctant to comply with public health programs. Addressing barriers to health care in vulnerable groups is critical to effective public health disaster response.

  9. DC Rocks! Using Place-Based Learning to Introduce Washington DC's K-12 Students to the Geosciences

    Science.gov (United States)

    Mayberry, G. C.; Mattietti, G. K.

    2017-12-01

    The Washington DC area has interesting geology and a multitude of agencies that deal with the geosciences, yet K-12 public school students in DC, most of whom are minorities, have limited exposure to the geosciences. Geoscience agencies in the DC area have a unique opportunity to address this by introducing the geosciences to local students who otherwise may not have such an opportunity, by highlighting the geology in the students' "backyard," and by leveraging partnerships among DC-based geoscience-related agencies. The USGS and George Mason University are developing a project called DC Rocks, which will give DC's students an exciting introduction into the world of geoscience with place-based learning opportunities that will make geoscience relevant to their lives and their futures. Both the need in DC and the potential for lasting impact are great; the geosciences have the lowest racial diversity of all the science, technology, engineering, and math (STEM) fields, 89% of students in DC public schools are minorities, and there is no dedicated geoscience curriculum in DC. DC Rocks aims to give these students early exposure to the earth sciences, and encourage them to consider careers in the profession. DC Rocks will work with partner agencies to apply several methods that are recommended by researchers to increase the participation of minority students in the geosciences, including providing profoundly positive experiences that spark interest in the geosciences (Levine et al., 2007); increasing students' sense of belonging in the geosciences (Huntoon, et al, 2016); and place-based teaching practices that emphasize the study of local sites (Semken, 2005), such as DC's Rock Creek Park. DC Rocks will apply these methods by coordinating local geoscientists and resources to provide real-world examples of the geosciences' impact on students' lives. Through the DC Rocks website, educators will be able to request geoscience-related resources such as class presentations by

  10. 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

  11. Energy Savings Analysis of the Proposed Revision of the Washington D.C. Non-Residential Energy Code

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, Michael I.; Athalye, Rahul A.; Hart, Philip R.

    2017-12-01

    This report presents the results of an assessment of savings for the proposed Washington D.C. energy code relative to ASHRAE Standard 90.1-2010. It includes annual and life cycle savings for site energy, source energy, energy cost, and carbon dioxide emissions that would result from adoption and enforcement of the proposed code for newly constructed buildings in Washington D.C. over a five year period.

  12. Can learning in informal settings mitigate disadvantage and promote urban sustainability? School gardens in Washington, DC

    Science.gov (United States)

    Fisher-Maltese, Carley; Fisher, Dana R.; Ray, Rashawn

    2017-09-01

    This article explores how school gardens provide learning opportunities for school-aged children while concurrently helping cities achieve sustainability. The authors analyse this process in Washington, DC, a particularly innovative metropolis in the United States. This national capital city boasts two of the most progressive examples of legislation aimed at improving environmental awareness and inciting citizens to engage in environmental stewardship, both of which focus on school-aged children: (1) the Healthy Schools Act of 2010 and (2) the Sustainable DC Act of 2012. Together these policies focus on bringing healthy lifestyles and environmental awareness, including meaningful outdoor learning experiences, to students and families in the District of Columbia. This article is organised into three parts. The first part discusses how Washington, DC became a sustainable learning city through the implementation of these specific policies. The next part presents the results of a pilot study conducted in one kindergarten to Grade 5 (K-5) elementary school located in Ward 8, the poorest part of the city. The authors' analysis considers the support and the obstacles teachers and principals in the District of Columbia (DC) are experiencing in their efforts to integrate school gardens into the curriculum and the culture of their schools. Exploring the impacts of the school garden on the students, the local community, and the inter-generational relationships at and beyond schools, the authors aim to shed light on the benefits and the challenges. While Washington, DC is fostering its hope that the benefits prevail as it provides a model for other cities to follow, the authors also candidly present the challenges of implementing these policies. In the final part, they discuss the implications of their findings for school gardens and sustainable learning cities more broadly. They encourage further research to gain more insights into effective ways of promoting environmental

  13. 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...

  14. Partners In Motion And Customer Satisfaction In The Washington Dc Metropolitan Area

    Science.gov (United States)

    1999-06-01

    PARTNERS IN MOTION IS A PROGRAM AIMED AT IMPROVING THE QUALITY, QUANTITY, AND AVAILABILITY OF TRAVEL INFORMATION TO TRANSPORTATION AGENCIES, THE MEDIA, AND, ULTIMATELY, TO THE TRAVELER IN THE WASHINGTON, D.C. METROPOLITAN AREA. THE PROGRAM WAS INITIA...

  15. Needs Assessment of the Healthcare Sector in the Washington, D.C., Metropolitan Area. Research Report. Business Needs Assessment Study.

    Science.gov (United States)

    Northern Virginia Community Coll., Annandale. Office of Institutional Research.

    According to the U.S. Bureau of Labor Statistics, the growing population of elderly citizens will result in an increased demand for healthcare services that will rise for a full 50 years. This study assesses the need for healthcare sector workers in the Washington, D.C. metropolitan area. Information on the skills, education, and experience that…

  16. Spacelab ready for transport to Washington, DC

    Science.gov (United States)

    1998-01-01

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

  17. 78 FR 37104 - Establishment of Area Navigation (RNAV) Routes; Washington, DC

    Science.gov (United States)

    2013-06-20

    ...-0081; Airspace Docket No. 12-AEA-5] RIN 2120-AA66 Establishment of Area Navigation (RNAV) Routes... Register approves this incorporation by reference action under 1 CFR part 51, subject to the annual... establishing five RNAV routes in the Washington, DC area (78 FR 29615). Subsequent to publication, it was...

  18. Flavonoids and heart health: Proceedings of the ILSI North America Flavonoids Workshop may 31-june 1, 2005, Washington DC

    NARCIS (Netherlands)

    Erdman, J.W.; Balentine, D.; Arab, L.; Beecher, G.; Dwyer, J.T.; Folts, J.; Harnly, J.; Hollman, P.C.H.; Keen, C.L.; Mazza, G.; Messina, M.; Scalbert, A.; Vita, J.; Williamson, G.; Burrows, J.

    2007-01-01

    This article provides an overview of current research on flavonoids as presented during a workshop entitled, "Flavonoids and Heart Health," held by the ILSI North America Project Committee on Flavonoids in Washington, DC, May 31 and June 1, 2005. Because a thorough knowledge and understanding about

  19. 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

  20. A green roof grant program for Washington DC

    International Nuclear Information System (INIS)

    Johnson, P.A.

    2007-01-01

    The Chesapeake Bay Foundation (CBF) began its green roof demonstration project with $300,000 in funding provided by the DC Water and Sewer Authority. This paper reviewed the history of the project, its goals and early findings. The main objective was to demonstrate the technical, policy and economic feasibility of installing green roofs on commercial buildings in Washington DC and to promote green roofs as a means to manage storm water and improve water quality through the reduction of excessive runoff. The CBF has issued grants for the installation of 7 green roofs varying in size, design, location, and use. The projects included both new and existing structures designed to improve storm-water management in an urban area with significant pollution stress on the adjacent rivers. This paper provided technical, cost, and performance evaluations of each roof. A public outreach segment provided information to decision-makers to encourage more widespread replication of green roof technology throughout the metropolitan area. Much of the District of Columbia is served by a combined sewer system that becomes overloaded and discharges raw sewage into adjacent rivers during even moderately heavy rains. An average of 75 overflow events each year result in 1.5 billion gallons discharged into the Anacostia River. The installation of green roofs on buildings in the combined sewer area would retain storm water during these heavy rains and reduce the amount of overflow discharges. Apartments, as well as commercial and government buildings with mostly flat roofs are the most likely candidates for green roofs. The demonstration roofs are intended to become models, which all building owners could use as a guide for future plans for construction or re-construction to expand green roof coverage in Washington DC. It was emphasized that although such large-scale replication will take time and financial investments, it is achievable given enough political will and commercial awareness of

  1. National Nuclear Waste Policy Act of 1981. Hearings before the Committee on Environment and Public Works, United States Senate, Ninety-Seventh Congress, First Session on S. 1662, October 31, 1981, Richland, Washington; November 9, 1981, Washington, DC

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    Hearings were held on October 31, 1981 in Richland, Washington and on November 9, 1981 in Washington, DC to discuss the effort in S. 1662 to establish a national policy and an environmentally acceptable program for managing nuclear wastes from domestic commercial activities. The Richland hearing was held in recognition that Washington State will bear the major impact of the legislation. Witnesses at the Washington, DC hearing included officials from states that are potential sites for radioactive waste storage and disposal facilities. The hearing record includes the testimony of 16 witnesses in Richland and seven in Washington, DC, followed by a reprint of S. 1662 and additional material submitted for the record

  2. Drug Treatment in New York City and Washington, D.C.: Followup Studies.

    Science.gov (United States)

    Burt Associates, Inc., Bethesda, MD.

    This report assesses the experiences of clients who had contact with or received drug abuse treatment from programs of the Addiction Services Agency in New York City and the Narcotics Treatment Administration in Washington, D.C. during the early 1970's. To answer the questions of what happens to former clients once they leave drug treatment…

  3. 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…

  4. 75 FR 1406 - National Mall and Memorial Parks, Washington, DC; Notice of Availability of an Environmental...

    Science.gov (United States)

    2010-01-11

    ... Washington, DC. The National Mall Plan is a long-range management plan that focuses on the use and... Spain, Project Executive. Before including your address, phone number, e-mail address, or other personal... Impact Statement. FOR FURTHER INFORMATION CONTACT: Susan Spain, Project Executive, National Mall Plan at...

  5. 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…

  6. Cigarette price variation around high schools: evidence from Washington DC.

    Science.gov (United States)

    Cantrell, Jennifer; Ganz, Ollie; Anesetti-Rothermel, Andrew; Harrell, Paul; Kreslake, Jennifer M; Xiao, Haijun; Pearson, Jennifer L; Vallone, Donna; Kirchner, Thomas R

    2015-01-01

    This study examines lowest cigarette prices in all tobacco retail outlets in Washington D.C. (n=750) in relation to the type and number of high schools nearby, controlling for confounders. The lowest overall and Newport menthol prices were significantly lower at outlets near public non-charter and charter schools compared with outlets near private schools. Given higher smoking prevalence and more price-sensitive youth subgroups in U.S. public schools, exposure to low prices may contribute to tobacco-related health disparities in minority and low-income populations. Tobacco taxes combined with policies to minimize the increasing use of price as a marketing tool are critical. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Enjoying green cities: Assessing visitors' attitude and preferences of urban forests in Washington, D.C.

    Science.gov (United States)

    Rogelio II Andrada; Jinyang. Deng

    2012-01-01

    This study examined the attitudes and preferences of visitors toWashington, D.C., one of the top tourism cities in the United States. Results of a visitor survey conducted at two sites show that respondents have a highly positive attitude towards the city's urban forest and that their appreciation of the urban forest has a positive influence on their experiences...

  8. Summary Proceedings of the Future Navigation Systems Planning Conference, held 3-4 August 1982, Washington, DC.

    Science.gov (United States)

    1982-09-01

    U.S. civil system managed by the civil administration, but it would be even easier if it were a system agreed to and Jointly financed by ICAO or some... Unicorns Park Drive 955 L’Enfant Plaza Woburn, MA 01801 Washington, D.C. 20024 84 r. C. Dennis Wright Aircraft Owners & Pilots Association P.O. Box 5800

  9. 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 (c) 2016 APA, all rights reserved).

  10. 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.

  11. Psychological resilience: the impact of affectivity and coping on state anxiety and positive emotions during and after the Washington, DC sniper killings.

    Science.gov (United States)

    Moore, Philip J; Chrabaszcz, Jeffrey S; Peterson, Rolf A; Rohrbeck, Cynthia A; Roemer, Enid C; Mercurio, Andrea E

    2014-01-01

    This research examined the impact of affectivity and coping on state anxiety and positive emotions among young adults living in the Washington, DC metro area both during and after the Washington, DC sniper killings. Participants completed questionnaires during three waves of data collection: (1) during the sniper attacks (n=92); (2) within two weeks after the snipers were captured (n=45); and (3) six months later (n=43). Affectivity (measured by neuroticism) was significantly associated with state anxiety and positive emotions during all three time periods. Coping (measured by constructive thinking) predicted state anxiety and positive emotions during the shootings, but was unrelated to either outcome immediately after the attacks, and marginally related to them six months later. Consistent with the Dynamic Model of Affect, state anxiety and positive emotions were more strongly (and negatively) correlated with each other during the killings than they were after the snipers were apprehended. Taken together, these results support transactional models of stress that emphasize the interaction between dispositional and situational influences, and they suggest that affectivity reflects a fundamental set of reactions to one's environment, while coping dispositions result in more stress-specific responses. Additional theoretical and practical implications of these findings are also discussed.

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

    Science.gov (United States)

    Weiss, Emily; Slater, Margaret; Garrison, Laurie; Drain, Natasha; Dolan, Emily; Scarlett, Janet M.; Zawistowski, Stephen L.

    2014-01-01

    Simple Summary 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 that one way to increase the lives saved with regard to large dogs in shelters is to keep them home in the first place when possible. Our research is the first to collect data in New York City and Washington, D.C., identifying the process leading to the owner relinquishment of large dogs. We found that targets for interventions to decrease large dog relinquishment are likely different in each community. Abstract 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. PMID:26480315

  13. 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.

  14. 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!

  15. THE ROLE OF HISTORICAL AERIAL PHOTOGRAPHS IN THE REMEDIATION OF WWI CHEMICAL CONTAMINATION IN THE SPRING VALLEY SUPERFUND SITE, 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...

  16. An Analysis of Wintertime Winds in Washington, D.C.

    Energy Technology Data Exchange (ETDEWEB)

    Berg, Larry K.; Allwine, K Jerry

    2006-06-20

    This report consists of a description of the wintertime climatology of wind speed and wind direction around the National Mall in Washington, D.C. Meteorological data for this study were collected at Ronald Reagan Washington National Airport (Reagan National), Dulles International Airport (Dulles), and a set of surface meteorological stations that are located on a number of building tops around the National Mall. A five-year wintertime climatology of wind speed and wind direction measured at Reagan National and Dulles are presented. A more detailed analysis was completed for the period December 2003 through February 2004 using data gathered from stations located around the National Mall, Reagan National, and Dulles. Key findings of our study include the following: * There are systematic differences between the wind speed and wind direction observed at Reagan National and the wind speed and wind direction measured by building top weather stations located in the National Mall. Although Dulles is located much further from the National Mall than Reagan National, there is better agreement between the wind speed and wind direction measured at Dulles and the weather stations in the National Mall. * When the winds are light (less than 3 ms-1 or 7 mph), there are significant differences in the wind directions reported at the various weather stations within the Mall. * Although the mean characteristics of the wind are similar at the various locations, significant, short-term differences are found when the time series are compared. These differences have important implications for the dispersion of airborne contaminants. In support of wintertime special events in the area of the National Mall, we recommend placing four additional meteorological instruments: three additional surface stations, one on the east bank of the Potomac River, one south of the Reflecting Pool (to better define the flow within the Mall), and a surface station near the Herbert C. Hoover Building; and wind

  17. Patterns of HIV/AIDS, STI, Substance Abuse and Hepatitis Risk among Selected Samples of Latino and African-American Youth in Washington, DC

    Science.gov (United States)

    Edberg, Mark C.; Collins, Elizabeth; Harris, Meredith; McLendon, Hedda; Santucci, Patricia

    2009-01-01

    In order to address evolving risk factors among youth in Washington, DC (District of Columbia), with respect to HIV/AIDS, sexually transmitted infections (STIs), substance abuse, and hepatitis, a targeted, community-needs assessment was conducted through a partnership between the Department of Prevention and Community Health at George Washington…

  18. Geologic map of the Washington West 30’ × 60’ quadrangle, Maryland, Virginia, and Washington D.C.

    Science.gov (United States)

    Lyttle, Peter T.; Aleinikoff, John N.; Burton, William C.; Crider, E. Allen; Drake, Avery A.; Froelich, Albert J.; Horton, J. Wright; Kasselas, Gregorios; Mixon, Robert B.; McCartan, Lucy; Nelson, Arthur E.; Newell, Wayne L.; Pavlides, Louis; Powars, David S.; Southworth, C. Scott; Weems, Robert E.

    2018-01-02

    The Washington West 30’ × 60’ quadrangle covers an area of approximately 4,884 square kilometers (1,343 square miles) in and west of the Washington, D.C., metropolitan area. The eastern part of the area is highly urbanized, and more rural areas to the west are rapidly being developed. The area lies entirely within the Chesapeake Bay drainage basin and mostly within the Potomac River watershed. It contains part of the Nation's main north-south transportation corridor east of the Blue Ridge Mountains, consisting of Interstate Highway 95, U.S. Highway 1, and railroads, as well as parts of the Capital Beltway and Interstate Highway 66. Extensive Federal land holdings in addition to those in Washington, D.C., include the Marine Corps Development and Education Command at Quantico, Fort Belvoir, Vint Hill Farms Station, the Naval Ordnance Station at Indian Head, the Chesapeake and Ohio Canal National Historic Park, Great Falls Park, and Manassas National Battlefield Park. The quadrangle contains most of Washington, D.C.; part or all of Arlington, Culpeper, Fairfax, Fauquier, Loudoun, Prince William, Rappahannock, and Stafford Counties in northern Virginia; and parts of Charles, Montgomery, and Prince Georges Counties in Maryland.The Washington West quadrangle spans four geologic provinces. From west to east these provinces are the Blue Ridge province, the early Mesozoic Culpeper basin, the Piedmont province, and the Coastal Plain province. There is some overlap in ages of rocks in the Blue Ridge and Piedmont provinces. The Blue Ridge province, which occupies the western part of the quadrangle, contains metamorphic and igneous rocks of Mesoproterozoic to Early Cambrian age. Mesoproterozoic (Grenville-age) rocks are mostly granitic gneisses, although older metaigneous rocks are found as xenoliths. Small areas of Neoproterozoic metasedimentary rocks nonconformably overlie Mesoproterozoic rocks. Neoproterozoic granitic rocks of the Robertson River Igneous Suite intruded

  19. Texts of joint USA-USSR statements following the summit meeting in Washington, D.C., 31 May - 3 June 1990

    International Nuclear Information System (INIS)

    1990-07-01

    The texts of joint USA-USSR statements following the summit meeting in Washington, D.C., 31 May - 3 June 1990 are reproduced. One is a joint statement on non-proliferation of nuclear weapons, missile and missile technology and chemical weapons, another one is a joint statement on the International Thermonuclear Experimental Reactor and the last one is a joint statement on Cooperation in Peaceful Uses of Atomic Energy

  20. 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.

  1. Arms control in space: workshop proceedings, Washington, DC, January 30-31, 1984

    International Nuclear Information System (INIS)

    1984-05-01

    In late 1982 and early 1983, the Subcommittee on Arms Control, Oceans, International Operations, and Environment of the Senate Committee on Foreign Relations held hearings on space weapons and arms control. To explore these issues further in a discussion format not easily achieved in hearings, Sen. Larry Pressler, Chairman of the Subcommittee, asked OTA to conduct a workshop focusing on antisatellite (ASAT) weapons as one aspect of space arms control. The workshop held in Washington, DC on January 30 and 31, 1984, provided an opportunity for technical, diplomatic, military, and policy-analysis experts to interact, think out loud, and build each other's ideas. The workshop was organized into six sessions, although issues involving anti-satellite weapons and arms control are not easily compartmentalized into distinct subject areas. Each session was introduced by a 10- or 15-minute informal oral presentation which set the stage for further discussion. This workshop proceedings volume is organized along the same divisions as the sessions, with some rearrangement

  2. 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).

  3. VSP - Discussion: The Common Interest on Planning Hulls and Plan for Collaboration Studies between NSWC and KRISO - Washington DC

    Science.gov (United States)

    2016-03-07

    planning hulls and plan for N62909-15-1-2052 collaboration studies between NSWC and KRISO - Washington DC Sb. GRANT NUMBER N62909-15-1-2052 Sc. PROGRAM...be carried out in MASK’s facilities. We discussed common interests on planing hulls, and made plans for collaboration studies between NSWC and KRISO ...Presentation of USV project in KRISO 8/19/2015 (Wed) • Discussion of common interests about planing hu lls • Planning for collaboration studies

  4. Survey about pedestrian safety and attitudes toward automated traffic enforcement in Washington, D.C.

    Science.gov (United States)

    Cicchino, Jessica B; Wells, Joann K; McCartt, Anne T

    2014-01-01

    Pedestrians represent more than one third of all traffic deaths in Washington, D.C. The District plans to expand its long-standing automated traffic enforcement program in 2013 from speed and red light cameras to cameras to enforce pedestrian right-of-way laws at crosswalks and stop sign laws. This study collected information on the opinions, behaviors, and knowledge of D.C. residents related to camera enforcement and pedestrian safety issues. A telephone survey of 801 adult D.C. residents was conducted in November 2012 with approximately equal numbers of respondents in each of D.C.'s eight wards. Quotas were used to ensure that the sample was representative of the demographic characteristics of adults in each ward. For analyses combining responses across the wards, data were weighted to correspond with the demographic characteristics of adults in the city. Most respondents believed that drivers speeding, running red lights, running stop signs, and not stopping for pedestrians are serious threats to their safety. Respondents strongly supported the speed and red light camera programs, with 76 percent of respondents favoring speed cameras and 87 percent favoring red light cameras. Support was more limited for the camera enforcement that was not yet in place at the time of the survey, with 50 percent of respondents favoring stop sign cameras and 47 percent of respondents favoring crosswalk cameras. Twenty-four percent of respondents had not driven a car in D.C. in the past month, and higher proportions of these nondrivers favored speed cameras (90%), stop sign cameras (67%), and crosswalk cameras (59%) than respondents who drove in D.C. in the past month. Respondents who supported camera enforcement cited safety as their main reason. More than 9 in 10 respondents knew that D.C. law requires drivers to stop for pedestrians crossing the street in marked crosswalks at intersections without traffic signals and midblock, but only 54 percent knew that drivers must stop for

  5. An assessment of solar hot water heating in the Washington, D.C. area - Implications for local utilities

    Science.gov (United States)

    Stuart, M. W.

    1980-04-01

    A survey of residential solar hot water heating in the Washington, D.C. area is presented with estimates of the total solar energy contribution per year. These estimates are examined in relation to a local utility's peak-load curves to determine the impact of a substantial increase in solar domestic hot water use over the next 20 yr in the area of utility management. The results indicate that a 10% market penetration of solar water heaters would have no detrimental effect on the utility's peak-load profile and could save several million dollars in new plant construction costs.

  6. 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

    ... Jersey Avenue, SE., Washington, DC 20590. FOR FURTHER INFORMATION CONTACT: Wahib Mina, Aerospace Engineer... requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Wahib Mina, Aerospace...

  7. Problems of Journalism; Proceedings of the 1975 Annual Convention of the American Society of Newspaper Editors (Washington, D.C., April 16-18, 1975).

    Science.gov (United States)

    American Society of Newspaper Editors, Easton, PA.

    This document reports the 1975 proceedings of the American Society of Newspaper Editors (ASNE) convention held in Washington, D.C., April 16-18. The contents include a list of officers and directors, past presidents of the society, and a copy of the ASNE Code of Ethics. Also contained in the document are reports on such individual sessions as…

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

    Science.gov (United States)

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

    2013-11-06

    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.

  9. 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.

  10. 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

    International Nuclear Information System (INIS)

    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

  11. Directions in engineering research: an assessment of opportunities and needs

    National Research Council Canada - National Science Library

    National Research Council Staff; Commission on Engineering and Technical Systems; Division on Engineering and Physical Sciences; National Research Council

    1987-01-01

    ... Commission on Engineering and Technical Systems National Research Council Washington, D.C. NATIONAL ACADEMY PRESS Washington, D.C. 1987 i Copyrightthe cannot be not from book, paper however, version for formatting, original authoritative the typesetting-specific the as from created publication files XML from other this and of recomposed styles, v...

  12. Βιβλιοκρισία:A. WEYL CARR - A. NICOLAIDES (eds., Asinou across Time: Studies in the Architecture and Murals of the Panagia Phorbiotissa, Cyprus. Dumbarton Oaks Studies, 43. Washington, DC:, 2012.

    Directory of Open Access Journals (Sweden)

    Bασιλική ΦΩΣΚΟΛΟΥ

    2015-04-01

    Full Text Available Bιβλιοκρισία:Annemarie Weyl Carr -Andréas Nicolaïdès (eds., Asinou across Time: Studies in the Architecture and Murals of the Panagia Phorbiotissa, Cyprus. Dumbarton Oaks Studies, 43. Washington, DC: Dumbarton Oaks Research Library and Collection, 2012. Pp. xii, 431.  ISBN 9780884023494.

  13. Map Sensitivity vs. Map Dependency: A Case Study of Subway Maps’ Impact on Passenger Route Choices in Washington DC

    Directory of Open Access Journals (Sweden)

    John Xu

    2017-10-01

    Full Text Available This paper addresses the key assumption in behavioral and transportation planning literature that, when people use a transit system more frequently, they become less dependent on and less sensitive to transit maps in their decision-making. Therefore, according to this assumption, map changes are much less impactful to travel decisions of frequent riders than to that of first-time or new passengers. This assumption—though never empirically validated—has been the major hurdle for transit maps to becoming a planning tool to change passengers’ behavior. This paper examines this assumption using the Washington DC metro map as a case study by conducting a route choice experiment between 30 Origin-Destination (O-D pairs on seven metro map designs. The experiment targets two types of passengers: frequent metro riders through advertisements on a free daily newspaper available at DC metro stations, and general residents in the Washington metropolitan area through Amazon Mechanical Turk, an online crowdsourcing platform. A total of 255 and 371 participants made 2024 and 2960 route choices in the respective experiments. The results show that frequent passengers are in fact more sensitive to subtle changes in map design than general residents who are less likely to be familiar with the metro map and therefore unaffected by map changes presented in the alternative designs. The work disproves the aforementioned assumption and further validates metro maps as an effective planning tool in transit systems.

  14. 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.

  15. Drilling history core hole DC-4

    International Nuclear Information System (INIS)

    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

  16. Quantifying the Consumptive Landscape in the Potomac Watershed Upstream From Washington DC

    Science.gov (United States)

    Kearns, M.; Zegre, N.; Fernandez, R.

    2017-12-01

    Some of the largest and fastest-growing eastern cities depend upon Appalachian headwaters for their fresh water. Today's relative abundance of water may be at risk: changes in climate and land use could alter the availability of surface water and human consumption could increase to meet the needs of a growing population and economy. Neither the supply of surface water nor the various withdrawals that support our population, irrigation, energy, and industry are distributed uniformly throughout our watersheds. This study correlates surface water withdrawals, consumptive use coefficients, and land-use/land-cover datasets to create a model for quantifying anthropogenic water consumption. The model suggests a method for downscaling and redistributing USGS county-level surface water withdrawals to 30 meter cells. Initially completed for the Potomac River watershed upstream from Washington DC's public supply intake, this approach could easily scale regionally or nationally. When combined with runoff estimates over the same landscape, the net-production or net-consumption of an area of interest may be calculated at high resolution. By better understanding the spatial relationship between hydrologic supply and demand, we can seek to improve the efficiency and security of our water resources.

  17. The Society for Pediatric Radiology, 38th annual meeting, Washington, DC, USA, April 27-30, 1995. Gold medalists, honorary members, pioneer session, abstracts

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    The contribution reports the highlights of the 38th annual meeting of the Society for Pediatric Radiology in Washington, DC, from 27 - 30 April, 1995. The abstracts of the 96 papers presented at the sessions on all pediatric subject fields are reproduced, and the gold medalists of the Society of the year 1995 are introduced with a brief c.v. and a survey of their careers. (VHE) [de

  18. "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).

  19. 75 FR 32736 - Notice of Solicitation for Members of the National Agricultural Research, Extension, Education...

    Science.gov (United States)

    2010-06-09

    ... Independence Avenue, SW., Room 321-A, Whitten Building, Washington, DC 20250-0321. FOR FURTHER INFORMATION... Economics Advisory Board, 1400 Independence Avenue, SW., Room 321-A, Whitten Building, Washington, DC 20250... research, crop and animal science, land-grant institutions, non-land grant college or university with a...

  20. Spatial and temporal structure of typhoid outbreaks in Washington, D.C., 1906–1909: evaluating local clustering with the Gi* statistic

    Directory of Open Access Journals (Sweden)

    Curtis Andrew

    2006-03-01

    Full Text Available Abstract Background To better understand the distribution of typhoid outbreaks in Washington, D.C., the U.S. Public Health Service (PHS conducted four investigations of typhoid fever. These studies included maps of cases reported between 1 May – 31 October 1906 – 1909. These data were entered into a GIS database and analyzed using Ripley's K-function followed by the Gi* statistic in yearly intervals to evaluate spatial clustering, the scale of clustering, and the temporal stability of these clusters. Results The Ripley's K-function indicated no global spatial autocorrelation. The Gi* statistic indicated clustering of typhoid at multiple scales across the four year time period, refuting the conclusions drawn in all four PHS reports concerning the distribution of cases. While the PHS reports suggested an even distribution of the disease, this study quantified both areas of localized disease clustering, as well as mobile larger regions of clustering. Thus, indicating both highly localized and periodic generalized sources of infection within the city. Conclusion The methodology applied in this study was useful for evaluating the spatial distribution and annual-level temporal patterns of typhoid outbreaks in Washington, D.C. from 1906 to 1909. While advanced spatial analyses of historical data sets must be interpreted with caution, this study does suggest that there is utility in these types of analyses and that they provide new insights into the urban patterns of typhoid outbreaks during the early part of the twentieth century.

  1. Research on DC Micro-grid system of photovoltaic power generation

    Science.gov (United States)

    Zheng, Yiming; Wang, Xiaohui

    2018-01-01

    The use of energy has become a topic of concern, the demand of people for power grows in number or quantity with the development of economy. It is necessary to consider using new forms of power supply-microgrid system for distributed power supply. The power supply mode can not only effectively solve the problem of excessive line loss in the large power grid, but also can increase the reliability of the power supply, and is economical and environmental friendly. With the increasing of DC loads, in order to improve the utilization efficiency, the DC microgrid power supply problems are begin to be researched and integrated with the renewable energy sources. This paper researched the development of microgrid, compared AC microgrid with DC microgrid, summarized the distribution of DC bus voltage level, the DC microgrid network form, the control mode and the main power electronics elements of DC microgrid of photovoltaic power generation system. Today, the DC microgrid system is still in the development stage without uniform voltage level standard, however, it will come into service in the future.

  2. Washington, D.C. | Midmarket Solar Policies in the United States | Solar

    Science.gov (United States)

    development have kept SREC prices high. Recent DC solar initiatives (e.g., the Solar Advantage Plus Program ) have targeted low-income residents. Small businesses may be able to leverage resources from the DC residential and commercial customer-generators with systems powered by renewable-energy sources. DC's net

  3. 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.

  4. The Topologies Research of a Soft Switching Bidirectional DC/DC Converter

    DEFF Research Database (Denmark)

    Zhang, Qi; Zhang, Yongping; Sun, Xiangdong

    2017-01-01

    A soft-switching solution implemented to the traditional bidirectional DC/DC converter is developed. The soft-switching cell, which composed of three auxiliary switches, one resonant capacitor and one resonant inductor, is equipped in the traditional bidirectional DC/DC converter to realize circuit...... circle. And the proposed topology of bidirectional soft-switching dc-dc converter(TASBC) performs ideal soft switching at boost operations. The characteristics of the proposed converter has been verified by MATLAB simulations and experimental results....

  5. Organic Compounds in Potomac River Water Used for Public Supply near Washington, D.C., 2003-05

    Science.gov (United States)

    Brayton, Michael J.; Denver, Judith M.; Delzer, Gregory C.; Hamilton, Pixie A.

    2008-01-01

    Organic compounds studied in this U.S. Geological Survey (USGS) assessment generally are man-made, including, in part, pesticides, solvents, gasoline hydrocarbons, personal care and domestic-use products, and refrigerants and propellants. A total of 85 of 277 compounds were detected at least once among the 25 samples collected approximately monthly during 2003-05 at the intake of the Washington Aqueduct, one of several community water systems on the Potomac River upstream from Washington, D.C. The diversity of compounds detected indicate a variety of different sources and uses (including wastewater discharge, industrial, agricultural, domestic, and others) and different pathways (including treated wastewater outfalls located upstream, overland runoff, and ground-water discharge) to drinking-water supplies. Seven compounds were detected year-round in source-water intake samples, including selected herbicide compounds commonly used in the Potomac River Basin and in other agricultural areas across the United States. Two-thirds of the 26 compounds detected most commonly in source water (in at least 20 percent of the samples) also were detected most commonly in finished water (after treatment but prior to distribution). Concentrations for all detected compounds in source and finished water generally were less than 0.1 microgram per liter and always less than human-health benchmarks, which are available for about one-half of the detected compounds. On the basis of this screening-level assessment, adverse effects to human health are expected to be negligible (subject to limitations of available human-health benchmarks).

  6. 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...

  7. An annotated checklist of the vascular flora of Washington County Mississippi

    Science.gov (United States)

    Field explorations have yielded 257 species new to Washington County, Mississippi and Calandrinia ciliata (Ruiz & Pav.) DC. and Ruellia nudiflora (Engelm. & Gray) Urban new to the state. An annotated list of 796 taxa for Washington County is provided and excludes 62 species that were reported from ...

  8. Organochlorine chemical residues in Northern Cardinal (Cardinalis cardinalis) eggs from Greater Washington, DC USA

    Science.gov (United States)

    Schmitt, Christopher J.; Echols, Kathy R.; Peterman, Paul; Orazio, Carl; Grimm, Christiana; Tan, Shirlee; Diggs, Nora E.; Marra, Peter P.

    2018-01-01

    Northern Cardinal eggs from six neighborhoods near Washington DC were analyzed for organochlorine pesticides and PCBs. All compounds were detected more frequently and at higher concentrations in more heavily urbanized neighborhoods. DDT (mostly as p,pʹ-DDE) was detected in all neighborhoods. p,pʹ-DDT was typically 0.5‒16 ng/g (ww) in most suburban neighborhoods but was not detected (< 0.1 ng/g) in more rural areas; however, p,pʹ-DDT was 127‒1130 ng/g in eggs from two suburban Maryland nests and comprised 65.7% of total p,pʹ-DDT isomers in the most contaminated sample, indicating recent exposure to un-weathered DDT. Total chlordane (sum of 5 compounds) was 2‒70 ng/g; concentrations were greatest in older suburban neighborhoods. Total PCB (sum of detected congeners) was < 5‒21 ng/g. Congener patterns were similar in all neighborhoods and resembled those typical of weathered mixtures. Results indicate that wildlife remains exposed to low concentrations of legacy contaminants in suburban neighborhoods and that cardinal eggs can be used to monitor localized contamination.

  9. Drilling history core hole DC-8

    International Nuclear Information System (INIS)

    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

  10. 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.

  11. 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...

  12. Building-Resolved CFD Simulations for Greenhouse Gas Transport and Dispersion over Washington DC / Baltimore

    Science.gov (United States)

    Prasad, K.; Lopez-Coto, I.; Ghosh, S.; Mueller, K.; Whetstone, J. R.

    2015-12-01

    The North-East Corridor project aims to use a top-down inversion methodology to quantify sources of Greenhouse Gas (GHG) emissions over urban domains such as Washington DC / Baltimore with high spatial and temporal resolution. Atmospheric transport of tracer gases from an emission source to a tower mounted receptor are usually conducted using the Weather Research and Forecasting (WRF) model. For such simulations, WRF employs a parameterized turbulence model and does not resolve the fine scale dynamics generated by the flow around buildings and communities comprising a large city. The NIST Fire Dynamics Simulator (FDS) is a computational fluid dynamics model that utilizes large eddy simulation methods to model flow around buildings at length scales much smaller than is practical with WRF. FDS has the potential to evaluate the impact of complex urban topography on near-field dispersion and mixing difficult to simulate with a mesoscale atmospheric model. Such capabilities may be important in determining urban GHG emissions using atmospheric measurements. A methodology has been developed to run FDS as a sub-grid scale model within a WRF simulation. The coupling is based on nudging the FDS flow field towards that computed by WRF, and is currently limited to one way coupling performed in an off-line mode. Using the coupled WRF / FDS model, NIST will investigate the effects of the urban canopy at horizontal resolutions of 10-20 m in a domain of 12 x 12 km. The coupled WRF-FDS simulations will be used to calculate the dispersion of tracer gases in the North-East Corridor and to evaluate the upwind areas that contribute to tower observations, referred to in the inversion community as influence functions. Results of this study will provide guidance regarding the importance of explicit simulations of urban atmospheric turbulence in obtaining accurate estimates of greenhouse gas emissions and transport.

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

    Science.gov (United States)

    Ehsani, M.

    1993-01-01

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

  14. Do Not Forget About Public Transportation: Analysis of the Association of Active Transportation to School Among Washington, DC Area Children With Parental Perceived Built Environment Measures.

    Science.gov (United States)

    Roberts, Jennifer D; Rodkey, Lindsey; Ray, Rashawn; Saelens, Brian E

    2018-03-23

    Although the active transportation (AT) indicator received an F grade on the 2016 US Report Card on Physical Activity for Children and Youth, this AT assessment excluded public transportation. An objective of the Built Environment and Active Play Study was to assess youth AT, including public transportation, among Washington, DC area children in relation to parental perceptions of neighborhood built environment (BE) variables. Questionnaires were mailed to 2000 parents of children aged 7-12 years. AT to school (ATS) was assessed with the question: "In an average school week, how many days does your child use each of the following ways to get to and from school? (a) Walk; (b) Bike; (c) Car; (d) Bus or Metro." Parental perceived BE data were obtained through questionnaire items, and logistic regression was conducted to determine if BE variables were associated with youth ATS. The sample included 144 children (50% female; average age 9.7 years; 56.3% white; 23.7% African American; 10.4% Asian American). Over 30% used ATS-public transportation 5 days per week, and nearly 13% used ATS-walking daily. Parental perceived BE variables significantly predicted youth ATS-walking and ATS-public transportation. ATS-public transportation is common among Washington, DC area youth, and parental perceptions of BE can significantly predict ATS.

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

    Science.gov (United States)

    Harris, Jordan Lee; Balci, Yilmaz

    2015-01-01

    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.

  16. 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.

  17. Acute stroke imaging research roadmap

    NARCIS (Netherlands)

    Wintermark, Max; Albers, Gregory W.; Alexandrov, Andrei V.; Alger, Jeffry R.; Bammer, Roland; Baron, Jean-Claude; Davis, Stephen; Demaerschalk, Bart M.; Derdeyn, Colin P.; Donnan, Geoffrey A.; Eastwood, James D.; Fiebach, Jochen B.; Fisher, Marc; Furie, Karen L.; Goldmakher, Gregory V.; Hacke, Werner; Kidwell, Chelsea S.; Kloska, Stephan P.; Koehrmann, Martin; Koroshetz, Walter; Lee, Ting-Yim; Lees, Kennedy R.; Lev, Michael H.; Liebeskind, David S.; Ostergaard, Leif; Powers, William J.; Provenzale, James; Schellinger, Peter; Silbergleit, Robert; Sorensen, Alma Gregory; Wardlaw, Joanna; Warach, Steven

    The recent "Advanced Neuroimaging for Acute Stroke Treatment" meeting on September 7 and 8, 2007 in Washington DC, brought together stroke neurologists, neuroradiologists, emergency physicians, neuroimaging research scientists, members of the National Institute of Neurological Disorders and Stroke

  18. DC Home Appliances for DC Distribution System

    Directory of Open Access Journals (Sweden)

    MUHAMMAD KAMRAN

    2017-10-01

    Full Text Available This paper strengthens the idea of DC distribution system for DC microgrid consisting of a building of 50 apartments. Since the war of currents AC system has been dominant because of the paucity of research in the protection of the DC system. Now with the advance research in power electronics material and components, generation of electricity is inherently DC as by solar PV, fuel cell and thermoelectric generator that eliminates the rectification process. Transformers are replaced by the power electronics buck-boost converters. DC circuit breakers have solved the protection problems for both DC transmission and distribution system. In this paper 308V DC microgrid is proposed and home appliances (DC internal are modified to operate on 48V DC from DC distribution line. Instead of using universal and induction motors in rotary appliances, BLDC (Brushless DC motors are proposed that are highly efficient with minimum electro-mechanical and no commutation losses. Proposed DC system reduces the power conversion stages, hence diminishes the associated power losses and standby losses that boost the overall system efficiency. So in view of all this a conventional AC system can be replaced by a DC system that has many advantages by cost as well as by performance

  19. University of Washington Center for Child Environmental Health Risks Research

    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...

  20. 75 FR 10414 - Researcher Identification Card

    Science.gov (United States)

    2010-03-08

    ... capturing administrative information on the characteristics of our users. Other forms of identification are... use bar-codes on researcher identification cards in the Washington, DC, area. The plastic cards we... plastic researcher identification cards as part of their security systems, we issue a plastic card to...

  1. Recent developments: Washington focus

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    November was a quiet month in Washington. Although Congress has recessed until 1991, the Senate filled vacancies in party leadership positions created by November's elections. The House is expected to proceed with its changes in early December. The Nuclear Energy Forum was held in Washington, DC on November 11-14 to discuss the status of the nuclear industry in the USA. The Forum, held in conjunction with the American Nuclear Society's annual meeting, assembled a large number of CEO's from US, European, and Far Eastern utilities and vendors. The meeting concluded with an announcement by Philip Bayne, President of NYPA and chairman of the Nuclear Power Oversight Committee (NPOC), of the results of a year-long NPOC study entitled a open-quotes Strategic Plan for Building New Nuclear Power Plants.close quotes

  2. Researchers active in two recent international tribology conferences

    OpenAIRE

    Nystrom, Lynn A.

    2005-01-01

    Virginia Tech faculty and former graduate students, in collaboration with researchers in Poland and Sweden, co-authored five papers presented at the international World Tribology Congress III held in Washington, D.C.

  3. Financial Literacy and Education Research Priorities

    Science.gov (United States)

    Schuchardt, Jane; Hanna, Sherman D.; Hira, Tahira K.; Lyons, Angela C.; Palmer, Lance; Xiao, Jing Jian

    2009-01-01

    Twenty-nine scholars from public and private universities, non-profit organizations, and the federal government participated in a National Research Symposium on Financial Literacy and Education in October 2008 in Washington, DC. The purpose was to identify critical research questions that could inform outcomes-based financial education, relevant…

  4. Location | Frederick National Laboratory for Cancer Research

    Science.gov (United States)

    The Frederick National Laboratory for Cancer Research campus is located 50 miles northwest of Washington, D.C., and 50 miles west of Baltimore, Maryland, in Frederick, Maryland. Satellite locations include leased and government facilities extending s

  5. Research on key technology of planning and design for AC/DC hybrid distribution network

    Science.gov (United States)

    Shen, Yu; Wu, Guilian; Zheng, Huan; Deng, Junpeng; Shi, Pengjia

    2018-04-01

    With the increasing demand of DC generation and DC load, the development of DC technology, AC and DC distribution network integrating will become an important form of future distribution network. In this paper, the key technology of planning and design for AC/DC hybrid distribution network is proposed, including the selection of AC and DC voltage series, the design of typical grid structure and the comprehensive evaluation method of planning scheme. The research results provide some ideas and directions for the future development of AC/DC hybrid distribution network.

  6. Residential Energy Efficiency Research Planning Meeting Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    none,

    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.

  7. 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.

  8. Characteristics of Black Men Who Have Sex With Men in Baltimore, Philadelphia, and Washington, D.C.: Geographic Diversity in Socio-Demographics and HIV Transmission Risk.

    Science.gov (United States)

    German, Danielle; Brady, Kathleen; Kuo, Irene; Opoku, Jenevieve; Flynn, Colin; Patrick, Rudy; Park, Ju Nyeong; Adams, Joella; Carroll, Makeda; Simmons, Ron; Smith, Carlton R; Davis, Wendy W

    2017-07-01

    Baltimore, Philadelphia, and Washington, DC are geographically proximate cities with high HIV prevalence, including among black men who have sex with men (BMSM). Using data collected among BMSM in CDC's National HIV Behavioral Surveillance project, we compared socio-demographic characteristics, HIV risk behaviors, and service utilization to explore similarities and differences that could inform local and regional HIV intervention approaches. BMSM were recruited through venue time location sampling, June-December, 2011. Participants completed identical socio-behavioral surveys and voluntary HIV testing. Analyses were conducted among the full sample and those aged 18-24. Participants included 159 (DC), 364 (Baltimore), and 331 (Philadelphia) eligible BMSM. HIV prevalence was 23.1% (DC), 48.0% (Baltimore), 14.6% (Philadelphia) with 30.6%, 69.0%, 33.3% unrecognized HIV infection, respectively. Among BMSM 18-24, HIV prevalence was 11.1% (DC), 38.9% (Baltimore), 9.6% (Philadelphia) with unrecognized HIV infection 0.0%, 73.8%, 60.0% respectively. Compared with the other 2 cities, Baltimore participants were less likely to identify as gay/homosexual; more likely to report unemployment, incarceration, homelessness, sex exchange; and least likely to use the internet for partners. DC participants were more likely to have a college degree and employment. Philadelphia participants were more likely to report gay/homosexual identity, receptive condomless anal sex, having only main partners, and bars/clubs as partner meeting places. Sexually transmitted disease testing was universally low. Analyses showed especially high HIV prevalence among BMSM in Baltimore including among young BMSM. Socio-demographic characteristics and HIV infection correlates differed across cities but unrecognized HIV infection and unknown partner status were universally high.

  9. Nuclear waste - A view from Washington, DC

    International Nuclear Information System (INIS)

    Mc Cormack, M.

    1984-01-01

    The view from Washington is an optimistic one. With support of the vast amount of research, development and engineering that scientists and engineers have completed and will do in the future, this country certainly is now headed towards a successful and orderly program for handling all radioactive wastes safely and inexpensively. The high-level waste program, for instance, will require only about 2% of the cost of electricity produced from nuclear power. It is the need for the federal government to create, by law, a public corporation for handling the fuel cycle for commercial nuclear fuel. Such a Federal Nuclear Fuel Cycle Corporation (FNFCC) would handle almost all of the nuclear power fuel cycle in a manner similar to the DOE management of the fuel cycle for the weapons program. Except for the mining and milling of uranium and the fabrication of uranium (only) fuel elements, the federal government would pre-empt ownership of all facilities used in the fuel cycle and operate them by contract with private industry (as with the weapons fuel cycle). Ownership of all fissile and fertile material (and all existing and future fuel elements) would be preempted by law and vested in the FNFCC. Reprocessing fuel to extract and glassify waste for permanent geologic disposal is the most attractive method for handling spent fuel from a safety and environmental perspective. Also recycling fuel is probably more environmentally attractive than mining more uranium, especially from lower grade ores. This concept of an FNFCC has been suggested to the Administration and to some Congressional leaders. There has been no known opposition expressed, but there is some indication of a reluctance to undertake such a major problem-solving initiative in one step

  10. 78 FR 78506 - Research and Development; Public Meeting

    Science.gov (United States)

    2013-12-26

    ... Safety R&D Initiatives on Packaging Testing Paperless Hazard Communications Pilot Program Odorization of.... PHMSA-2013-0261; Notice No. 13-21] Research and Development; Public Meeting AGENCY: Pipeline and... the Research and Development Forum to be held January 17, 2014, in Washington, DC. During this meeting...

  11. Chemistry Research of Optical Fibers.

    Science.gov (United States)

    1982-09-27

    BROADENING IN OPTICAL FIBERS Herbert B. Rosenstock* Naval Research Laboratory Washington, DC 20375 ABSTRACT A light pulse transmitted through a fiber...Marcatili, Marcuse , and Personick, "Dispersion Properties of Fibers" (Ch. 4 in "Optical Fiber Telecommunications," S. E. Miller and A. C. Chynoweth, eds

  12. 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.

  13. 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.

  14. TOPOLOGICAL REVIEW AND ANALYSIS OF DC-DC BOOST CONVERTERS

    Directory of Open Access Journals (Sweden)

    V. INDRA GANDHI

    2017-06-01

    Full Text Available DC voltage boost up is essential in numerous applications; especially considering Photovoltaic (PV based renewable power generation system. The conventional DC-DC boost converter is the most admired configuration for this scheme, even if the converter efficiency is restricted at duty cycle near to maximum value. In order to find solution to the problem and improve its conversion capability, many converter configurations have been implemented so far. With this circumstance, this research work proposes to give overview of a few most imperative research works related to DC-DC boost converters. Some configurations are covered and classified basically based on the application. The major benefits and disadvantages related to the available techniques are also briefly conveyed. At last, a proper evaluation is recognized among the important types of DC-DC boost converters in terms of efficiency, number of components, and stability.

  15. Frontiers in chemical engineering: research needs and opportunities

    National Research Council Canada - National Science Library

    National Research Council Staff; Commission on Physical Sciences, Mathematics, and Applications; Division on Engineering and Physical Sciences; National Research Council

    1988-01-01

    ...: Research Needs and Opportunities Board on Chemical Sciences and Technology Commission on Physical Sciences, Mathematics, and Resources National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1988 i Copyrighttrue Please breaks inserted. are Page files. accidentally typesetting been have may original from the errors not typographic original ret...

  16. Father Secchi Goes to Washington

    Science.gov (United States)

    McCarthy, M. F.

    1994-12-01

    In 1848 a small group of Jesuit refugees arrived at Georgetown College near Washington, D.C. Among them was a young priest, Angelo Secchi, who had finished theology studies in Rome, but had not been able to complete his final examinations. This done successfully, Secchi turned to astronomy and the new facilities of the Georgetown College Observatory, directed by its founder, Fr. James Curley. During his two years in Washington, Secchi studied physics, wrote an article on Electrical Rheometry for the Smithsonian Institution, and formed a friendship with Matthew Fontaine Maury of the U.S. Navy, who headed the Chart Service and in 1844 was named superintendent of the National Observatory. This was later named the U.S. Naval Observatory. Secchi's friendships formed during the Washington visit proved most helpful for relations between European astronomers and U.S. colleagues. Secchi, after his return to Rome constructed the Observatory of the Collegio Romano atop the baroque Church of St. Ignatius in Rome and began his work in spectral classification of stars.

  17. 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

  18. An Urban Soccer Stadium for Washington D.C.

    OpenAIRE

    Ard, John Christopher

    2014-01-01

    Expansive parking lots, miles of asphalt, and traffic jams: this is what the modern sport stadia has come to represent. Does it have to be this way? What does the future of sports stadia hold? Can we build a stadium that is better integrated to the community around it? The stadium must become a major urban element again and it must engage the urban context. D.C. United, the most storied franchise in MLS history, needs a new home. Baltimore and other locations in Maryland would gladly we...

  19. 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.

  20. Employee Turnover and Absenteeism: A Future Research Agenda.

    Science.gov (United States)

    1981-08-01

    Department (NMPC-6) Washington, DC 20350 Naval Training Analysis and Evaluation Group Orlando, FL 32813 Commanding Officer ATTN: TIC , Bldg. 2068 Naval...RD-i Washington, DC 20380 Educacion Advisor Education Center (E031) MCDEC Quantico, VA 22134 Commanding Officer Education Center (E031) MCDZC Quantico

  1. Legal Immigration Status is Associated with Depressive Symptoms among Latina Transgender Women in Washington, DC

    Directory of Open Access Journals (Sweden)

    Thespina Yamanis

    2018-06-01

    Full Text Available Latina transgender women (LTW are disproportionately vulnerable to depression, although the role of immigration/documentation status (legal authority to live/work in the U.S. in depression has not been explored. LTW in Washington, DC were recruited into a cross-sectional study via convenience sampling. Most were Spanish-speaking Central American immigrants. Participants completed rapid HIV tests, and a Spanish-language survey assessing recent depressive symptoms (PHQ-2, sociodemographics, and factors from the minority stress framework: structural stressors (documentation status, stable housing, social stressors (discrimination, fear of deportation, violence and coping resources (social support, resilience. Among immigrant LTW (n = 38, 24 were undocumented. Among the undocumented, the average PHQ-2 score was 2.7, and among the documented, the average PHQ-2 score was 1.4 (p < 0.05. Undocumented LTW were significantly more likely to experience employment discrimination, recent unstable housing, and fear of deportation. Bivariate and multiple linear regressions were performed to assess the relationship between documentation status and other correlates of past two week depressive symptoms. In multivariate analysis, PHQ-2 scores were inversely associated with being documented (p < 0.01, having an income above the federal poverty level, higher friends’ social support, and increased resiliency. Documentation status is an important correlate of depressive symptoms among LTW that should be considered within the context of health interventions.

  2. 75 FR 33736 - Tart Cherries Grown in the States of Michigan, New York, Pennsylvania, Oregon, Utah, Washington...

    Science.gov (United States)

    2010-06-15

    ...., Stop 0237, Washington, DC 20250-0237; telephone: (202) 720-2491, Fax: (202) 720-8938, or E-mail: Laurel... DEPARTMENT OF AGRICULTURE Agricultural Marketing Service 7 CFR Part 930 [Doc. No. AO-370-A8; AMS..., Oregon, Utah, Washington, and Wisconsin; Withdrawal of Proposed Rule AGENCY: Agricultural Marketing...

  3. Use of Laboratory Animals in Biomedical and Behavioral Research

    National Research Council Canada - National Science Library

    1988-01-01

    ... of Laboratory Animals in Biomedical and Behavioral Research Commission on Life Sciences National Research Council Institute of Medicine NATIONAL ACADEMY PRESS Washington, D.C. 1988 Copyrightoriginal retained, the be not from cannot book, paper original however, for version formatting, authoritative the typesetting-specific created from the as publ...

  4. Russian delegation visits NIH and NCI to discuss research collaboration

    Science.gov (United States)

    The NCI Center for Global Health hosted a delegation from the Russian Foundation for Basic Research to discuss ongoing and future collaborations in cancer research. The delegation was accompanied by representatives from the US Embassy in Moscow and the Embassy of the Russian Federation in Washington DC.

  5. CCR presentations at AACR | Center for Cancer Research

    Science.gov (United States)

    CCR presentations at AACR Several CCR scientists will present their research at the AACR Annual Meeting in Washington, D.C., between April 1-5, 2017. Selected oral presentations are listed below. A full list of abstracts can be found on the AACR website.

  6. Assessment of research needs for wind turbine rotor materials technology

    National Research Council Canada - National Science Library

    National Research Council Staff; Commission on Engineering and Technical Systems; Division on Engineering and Physical Sciences; National Research Council; National Academy of Sciences

    1991-01-01

    ... on Assessment of Research Needs for Wind Turbine Rotor Materials Technology Energy Engineering Board Commission on Engineering and Technical Systems National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1991 Copyrightthe true use are Please breaks Page inserted. accidentally typesetting been have may original the from errors not...

  7. Examining the Influence of a New Light Rail Line on the Health of a Demographically Diverse and Understudied Population within the Washington, D.C. Metropolitan Area: A Protocol for a Natural Experiment Study

    Directory of Open Access Journals (Sweden)

    Jennifer D. Roberts

    2018-02-01

    Full Text Available Approximately two-thirds of adults and youth in Prince George’s County, Maryland, a suburb of Washington, D.C. are overweight or obese and less than half are achieving daily physical activity recommendations. Active transportation (AT, such as walking, biking or using public transportation (PT, is a strategic pathway to improving physical activity levels and thus reducing excess weight. Utilizing an expansion of the Washington, D.C. area transportation system with a new light rail line, the Purple Line Outcomes on Transportation (PLOT Study will exam pre- and post-Purple Line PT use, AT behaviors and attitudes and physical activity among Prince George’s County adults and youth. The PLOT Study will take advantage of this natural experiment in an area enduring significant racial/ethnic and gender-based overweight or obesity and physical inactivity disparities. While similar natural experiments on AT have been conducted in other U.S. cities, those studies lacked diverse and representative samples. To effectively evaluate these physical activity outcomes among this population, efforts will be used to recruit African American and Latino populations, the first and second most common racial/ethnic groups in Prince George’s County. Finally, the PLOT Study will also examine how contextual effects (e.g., neighborhood built environment impact PT, AT and physical activity.

  8. Examining the Influence of a New Light Rail Line on the Health of a Demographically Diverse and Understudied Population within the Washington, D.C. Metropolitan Area: A Protocol for a Natural Experiment Study

    Science.gov (United States)

    Saksvig, Brit Irene; Brachman, Micah L.; Durand, Casey P.

    2018-01-01

    Approximately two-thirds of adults and youth in Prince George’s County, Maryland, a suburb of Washington, D.C. are overweight or obese and less than half are achieving daily physical activity recommendations. Active transportation (AT), such as walking, biking or using public transportation (PT), is a strategic pathway to improving physical activity levels and thus reducing excess weight. Utilizing an expansion of the Washington, D.C. area transportation system with a new light rail line, the Purple Line Outcomes on Transportation (PLOT) Study will exam pre- and post-Purple Line PT use, AT behaviors and attitudes and physical activity among Prince George’s County adults and youth. The PLOT Study will take advantage of this natural experiment in an area enduring significant racial/ethnic and gender-based overweight or obesity and physical inactivity disparities. While similar natural experiments on AT have been conducted in other U.S. cities, those studies lacked diverse and representative samples. To effectively evaluate these physical activity outcomes among this population, efforts will be used to recruit African American and Latino populations, the first and second most common racial/ethnic groups in Prince George’s County. Finally, the PLOT Study will also examine how contextual effects (e.g., neighborhood built environment) impact PT, AT and physical activity.

  9. 2013 Building America Research Planning Meeting Summary

    Energy Technology Data Exchange (ETDEWEB)

    Metzger, C. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hunt, S. [Confluence Communications, Missoula, MT (united States)

    2014-02-01

    The Building America Research Planning Meeting was held October 28-30, 2013, in Washington, DC. This meeting provides one opportunity each year for the research teams, national laboratories and Department of Energy (DOE) managers to meet in person to share the most pertinent information and collaboration updates. This report documents the presentations, highlights key program updates, and outlines next steps for the program.

  10. The effects of water filtration systems on fluoride: Washington, D.C. metropolitan area.

    Science.gov (United States)

    Jobson, M D; Grimm, S E; Banks, K; Henley, G

    2000-01-01

    According to the U.S. Environmental Protection Agency (EPA), approximately one in eight Americans is exposed to potentially harmful microbes, pesticides, lead, or radioactive radon whenever they drink a glass of tap water or take a shower. One reason for this exposure is that the water plants are aging or ill equipped to process the huge amounts of raw sewage and agricultural pollutants that are still being discharged into our drinking-water sources. Other compounds such as fluoride and chloride have been added to the community water supplies for health benefits. Water filtration systems are becoming more popular as people become concerned with pollutants in the public water supply and questions are being raised as to whether fluoride is affected by these filters. The aim of this pilot study was to assess the efficacy of three types of water filtration systems and to determine their impact on fluoride content of the water in the Washington, D.C. metropolitan area. One sample of water was collected daily for fourteen days, from one location. The sample was divided to use as a control and the test samples which were processed through various filter systems. With the use of a fluoride ion specific electrode, the fluoride concentration level was tested in all samples in order to determine the percentage of fluoride removed. This study was intended to prove that the water filtration systems did not affect the advantage offered by optimum water fluoride levels. The experimental samples were ascertained and compared to the control group, resulting in three of the four carbon filters showing statistically significant amounts of fluoride removed from the water. Both Reverse Osmosis and Distillation, as expected, removed the fluoride at a high rate.

  11. PENGGUNAAN FUZZY LOGIC UNTUK KONTROL PARALLEL CONVERTER DC-DC

    Directory of Open Access Journals (Sweden)

    Bambang Prio Hartono

    2012-09-01

    Full Text Available Abstract: Using system fuzzy logic as control  technology have been used on low load dc-dc converter with combined parallel compiled  dc-dc converter can  obtain big load.   With existence of differrence of component parameter and each parallel compiled converter can obtained different current  and voltage output.  Function of controller  for to do adjustment, so that current which is applied  to  load by each converter  can be obtained  difference error as small as possible or same. The object of research is developing design of large signal dc-dc converter which is  combined with using  FLC so that  obtain  better performance.  To get better performance have been made plant model and simulation with CDE method.  The more systematic  system and design is needed to overcome bigger load  on dc-dc converter, so that parallel  compiled current master slave control system on dc-dc converter with using fuzzy logic  controller is used. Result of  research showed that error or difference of  current  which is applied to load can handled by fuzzy logic  controller.  Technic of current and voltage controller co to do adjustment current and voltage distribution  equally to load.  Distribution of iL1,iL2 and  output voltage Vo on dc-dc  converter with load 2,25 until  7,875 and voltage  100  until 120 volt,  load current beetwen  12 until 48, % relatif  error  Vo  0,4% until  0,9%.

  12. 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

  13. 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

  14. Seasonal variation of heavy metals in ambient air and precipitation at a single site in Washington, DC

    International Nuclear Information System (INIS)

    Melaku, Samuel; Morris, Vernon; Raghavan, Dharmaraj; Hosten, Charles

    2008-01-01

    Atmospheric samples of precipitation and ambient air were collected at a single site in Washington, DC, for 7 months (for ambient air samples) and 1 year (for wet deposition samples) and analyzed for arsenic, cadmium, chromium and lead. The ranges of heavy metal concentrations for 6-day wet deposition samples collected over the 1-year period were 0.20-1.3 μg/l, 0.060-5.1 μg/l, 0.062-4.6 μg/l and 0.11-3.2 μg/l for arsenic, cadmium, chromium and lead, respectively, with a precision better than 5% for more than 95% of the measurements. The ranges of heavy metal concentrations for the 6-day ambient air samples were 0.800-15.7 ng/m 3 , 1.50-30.0 ng/m 3 , 16.8-112 ng/m 3 , and 2.90-137 ng/m 3 for arsenic, cadmium, chromium and lead, respectively, with a precision better than 10%. The spread in the heavy metal concentration over the observation period suggests a high seasonal variability for heavy metal content in both ambient air and wet deposition samples. - High seasonal variability of heavy metals were observed in both ambient air and wet deposition samples

  15. 75 FR 46903 - Forestry Research Advisory Council

    Science.gov (United States)

    2010-08-04

    ... Development, 1400 Independence Ave., SW., Washington, DC 20250-1120, or fax their names and proposed agenda... Deputy Chief for Research and Development, (202) 205-1665. Individuals who use telecommunication devices for the deaf (TDD) may call the Federal Information Relay Service (FIRS) at 1-800-877-8339 between 8 a...

  16. The Influence of Family Dog Ownership and Parental Perceived Built Environment Measures on Children's Physical Activity within the Washington, DC Area.

    Science.gov (United States)

    Roberts, Jennifer D; Rodkey, Lindsey; Grisham, Cortney; Ray, Rashawn

    2017-11-16

    Sedentary behavior and physical inactivity are significant contributors to youth obesity in the United States. Neighborhood dog walking is an outlet for physical activity (PA). Therefore, understanding the relationship between built environment, dog ownership, and youth PA is essential. This study examined the influence of dog ownership and parental built environment perceptions on children's PA in the Washington, D.C. area. In 2014, questionnaires were mailed to 2000 parents to assess family dog ownership; children's outdoor dog walking or playing; and parental perceived built environment measures. Chi-square analyses examined differences in parental perceived built environment measures between children with and without family dogs. The sample included 144 children (50% female; average-age 9.7 years; 56.3% White; 23.7% African-American; 10.4% Asian-American; 29.9% owned dog). Only 13% and 5.6% of the children walked or played outdoors with the dog daily, respectively. A significantly greater proportion ( p -value supports children's outdoor PA through dog walking and playing.

  17. 75 FR 61025 - Softwood Lumber Research, Promotion, Consumer Education and Industry Information Order...

    Science.gov (United States)

    2010-10-01

    ... Information Order; Referendum Procedures AGENCY: Agricultural Marketing Service, USDA. ACTION: Proposed rule..., Washington, DC 20503. FOR FURTHER INFORMATION CONTACT: Maureen T. Pello, Marketing Specialist, Research and... procedure, Advertising, Consumer information, Marketing agreements, Softwood Lumber, Promotion, Reporting...

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

    Science.gov (United States)

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

    2010-02-01

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

  19. 77 FR 21622 - Rehabilitation Research and Development Service Scientific Merit Review Board; Notice of Meeting

    Science.gov (United States)

    2012-04-10

    ... DEPARTMENT OF VETERANS AFFAIRS Rehabilitation Research and Development Service Scientific Merit...-463 (Federal Advisory Committee Act) that a meeting of the Rehabilitation Research and Development Service Scientific Merit Review Board will be held on April 20, 2012, 131 M Street NE., Washington, DC...

  20. ACT-R/E: An Embodied Cognitive Architecture for Human-Robot Interaction

    Science.gov (United States)

    2013-01-01

    Threaded Cognition: An Integrated Theory of Concurrent Multitasking . Psychological Review, 115(1), 101–130, http://dx.doi.org/10.1037/0033-295X...Trafton, Naval Research Laboratory, Washington, DC, USA Email : greg.trafton@nrl.navy.mil Laura Hiatt, Naval Research Laboratory, Washington, DC, USA Email ...laura.hiatt@nrl.navy.mil Anthony Harrison, Naval Research Laboratory, Washington, DC, USA Email : anthony.harrison@nrl.navy.mil Frank Tamborello, Naval

  1. 2013 Building America Research Planning Meeting Summary

    Energy Technology Data Exchange (ETDEWEB)

    Metzger, Cheryn E. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hunt, Stacy [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2014-02-01

    The Building America (BA) Research Planning Meeting was held October 28-30, 2013, in Washington, DC. This meeting provides one opportunity each year for the research teams, national laboratories and Department of Energy (DOE) managers to meet in person to share the most pertinent information and collaboration updates. This report documents the presentations, highlights key program updates, and outlines next steps for the program.

  2. Original Research Original Research

    African Journals Online (AJOL)

    User

    2013-06-20

    Jun 20, 2013 ... Intimate partner violence against women undermine the well-being of women. Thus ...... Dares Salaam, Tanzania (Washington, DC: Horizons. Project/ICRW: 2000): ... GCWA_BG_Violence_en.pdf> [Accessed 11 march. 2008].

  3. 75 FR 55634 - National Research Advisory Council; Notice of Meeting

    Science.gov (United States)

    2010-09-13

    ... DEPARTMENT OF VETERANS AFFAIRS National Research Advisory Council; Notice of Meeting The Department of Veterans Affairs (VA) gives notice under Public Law 92-463 (Federal Advisory Committee Act... Phoenix Park Hotel, Federal City Room, 520 North Capitol Street, NW., Washington, DC. The meeting will...

  4. 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.

  5. Epithermal neutron beam for BNCT research at the Washington State University TRIGA research reactor

    International Nuclear Information System (INIS)

    Nigg, D.W.; Venhuizen, J.R.; Wheeler, F.J.; Wemple, C.A.; Tripard, G.E.; Gavin, P.R.

    2000-01-01

    A new epithermal-neutron beam facility for BNCT (Boron Neutron Capture Therapy) research and boronated agent screening in animal models is in the final stages of construction at Washington State University (WSU). A key distinguishing feature of the design is the incorporation of a new, high-efficiency, neutron moderating and filtering material, Fluental, developed by the Technical Research Centre of Finland. An additional key feature is the provision for adjustable filter-moderator thickness to systematically explore the radiobiological consequences of increasing the fast-neutron contamination above the nominal value associated with the baseline system. (author)

  6. The Competitive edge: research priorities for U.S. manufacturing

    National Research Council Canada - National Science Library

    National Research Council Staff; Commission on Engineering and Technical Systems; Board on Manufacturing and Engineering Design; Division on Engineering and Physical Sciences; National Research Council; National Academy of Sciences

    1991-01-01

    ... Manufacturing Studies Board Commission on Engineering and Technical Systems National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1991 i Copyrightthe cannot be not from book, paper however, version for formatting, original authoritative the typesetting-specific the as from created publication files XML from other this and of...

  7. The competitive edge: research priorities for U.S. manufacturing

    National Research Council Canada - National Science Library

    National Research Council Staff; Commission on Engineering and Technical Systems; Board on Manufacturing and Engineering Design; Division on Engineering and Physical Sciences; National Research Council; National Academy of Sciences

    1991-01-01

    ... Manufacturing Studies Board Commission on Engineering and Technical Systems National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1991 i Copyrightthe cannot be not from book, paper however, version for formatting, original authoritative the typesetting-specific the as from created publication files XML from other this and of...

  8. A one-size-fits-all HIV prevention and education approach?: Analyzing and interpreting divergent HIV risk perceptions between African American and East African immigrant women in Washington, DC

    Science.gov (United States)

    De Jesus, Maria; Taylor, Juanita; Maine, Cathleen; Nalls, Patricia

    2015-01-01

    Background To date, there are very few comparative US studies and none in DC that distinguish between US-born and foreign-born Black women to examine and compare their perceptions of HIV risk. This qualitative study, therefore, analyzes African American and East African women’s perceptions of HIV risk in the Washington DC Metropolitan area, which has the highest AIDS rate in the US. Methods Forty in-depth, semi-structured interviews and 10 cognitive interviews were conducted among a sample of 25 African American women and 25 East African born women between October 2012 and March 2013 to examine perceptions regarding HIV risk. The in-depth semi-structured interviews were preceded by the cognitive interviews and accompanying survey. Study protocol was reviewed and approved by the American University Institutional Review Board. Results Adopting Boerma and Weir’s Proximate Determinants conceptual framework to interpret the data, the results of the study demonstrate that African American and East African immigrant women have divergent perceptions of HIV risk. While African American women ascribe HIV risk to individual-level behaviors and choices such as unprotected sex, East African women attribute HIV risk to conditions of poverty and survival. Conclusions Study findings suggest that addressing HIV prevention and education among Black women in DC will require distinct and targeted strategies that are culturally and community-centered in order to resonate with these different audiences. PMID:26766523

  9. Research on Two-channel Interleaved Two-stage Paralleled Buck DC-DC Converter for Plasma Cutting Power Supply

    DEFF Research Database (Denmark)

    Yang, Xi-jun; Qu, Hao; Yao, Chen

    2014-01-01

    As for high power plasma power supply, due to high efficiency and flexibility, multi-channel interleaved multi-stage paralleled Buck DC-DC Converter becomes the first choice. In the paper, two-channel interleaved two- stage paralleled Buck DC-DC Converter powered by three-phase AC power supply...

  10. Health-hazard-evaluation report HETA 87-376-2018, US Department of Justice, United States Marshals Service, Washington, DC

    Energy Technology Data Exchange (ETDEWEB)

    Reh, C.M.; Klein, M.K.

    1990-03-01

    In response to a request from the United States Marshals Service (SIC-9221) in Washington, D.C. for assistance in testing the effect of renovations to the ventilation system of their indoor firing range, lead (7439921) exposures were measured during handgun qualifying sessions. Each qualifying session of firing consisted of 60 rounds fired in 10 to 12 minutes. Personal breathing zone air samples were taken from three shooters and the range officer. Lead exposure concentrations measured were 2073, 1786, 172, and 142 micrograms of lead per cubic meter of air (microg/cu m). Eight hour time weighted average concentrations were calculated to be 194, 167, 101, and 13microg/cu m, respectively. The three shooters were therefore overexposed to lead. Bulk sampling of the sand from the bullet trap indicated it to be contaminated, containing 41% lead by weight. The authors concluded that a health hazard existed from exposure to lead. The authors recommended changes to improve the ventilation system. Following modification of the system, tests were again conducted and 11 of the 12 samples taken were below the limits of detection for the method used. The authors conclude that after modification, a hazard did not exist during qualifying sessions. The authors recommend specific measures to protect personnel from exposure to lead.

  11. 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.

  12. Reading Research Utilization Project: An RIC Project for Teachers and Other Field Personnel.

    Science.gov (United States)

    District of Columbia Public Schools, Washington, DC. Dept. of Research and Evaluation.

    This is the final report of the Reading Research Utilization Project (RUP) which was funded by the U.S. Office of Education from July, 1971 to June, 1973. The purpose of the RUP was to encourage the translation of research, particularly reading research, into practice in 16 target elementary schools in Washington, D.C. RUP was a school information…

  13. Promoting health: intervention strategies from social and behavioral research

    National Research Council Canada - National Science Library

    Smedley, Brian D; Syme, S. Leonard

    ... on Capitalizing on Social Science and Behavioral Research to Improve the Public's Health Division of Health Promotion and Disease Prevention INSTITUTE OF MEDICINE NATIONAL ACADEMY PRESS Washington, D.C. i Copyrightthe cannot be not from book, paper however, version for formatting, original authoritative the typesetting-specific the as from created pu...

  14. 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.

  15. Research on Digital Output Verification Technology of Electronic DC Current Transformer

    Science.gov (United States)

    Chen, Yuanjie; Wang, Bin; Hu, Haoliang; Xiong, Qianzhu; Yang, Chunyan

    2017-05-01

    Aiming at the error of calibration system when conducting field calibration by electronic DC current transformer’s digital calibration system, an electronic DC current transformer’s digital calibration system based on protocol conversion is proposed and researched. Data frames outputted from merging unit are collected and converted by the system, the digital synchronization is realized by using the synchronous clock device to trigger the second pulse, and it is verified by the virtual instrument design software. The field calibration is conducted to some converter station digital dc current transformer under the rated current of 500A by using the calibration system. By calibrating and analyzing errors, the error is less than 0.075% when tested current is more than 40% of the rated current. According the standard in literature[1], performance of the calibration system is perfect, measured results perfectly meet the requirements of design, and the calibration system has great practical application value.

  16. 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.

  17. Chi Ka Sha Goes to Washington: Chickasaw Narratives on the NMAI

    Science.gov (United States)

    Hinson, Joshua Don

    2005-01-01

    This narrative describes the author's visit to Washington DC to attend the opening of the National Museum of the American Indian (NMAI). As a member of the Chickasaw, the author pondered what he would find in the museum that would represent the Chickasaw Nation. Would the museum reflect his people in all their diversity? Would he see something of…

  18. Research and service programs in the PHS: challenges in organization

    National Research Council Canada - National Science Library

    Institute of Medicine Staff; Institute of Medicine

    1991-01-01

    ... Committee on Co-Administration of Service and Research Programs of the National Institutes of Health, the Alcohol, Drug Abuse, and Mental Health Administration, and Related Agencies INSTITUTE OF MEDICINE NATIONAL ACADEMY PRESS Washington, D.C. 1991 Copyrightoriginal retained, the be not from cannot book, paper original however, for version formatting, author...

  19. The 1996 IDA Cost Research Symposium.

    Science.gov (United States)

    1996-08-01

    5160 Christopher Deegan (703)602-6575 Performer: Naval Surface Warfare Center (211) Carderock Division, NSWC/CD Bethesda, Maryland 20084-5000...Moore (703) 602-0330, ext 208 Cost Engineering Research, Inc. 2011 Crystal Drive Arlington, VA 22202-3717 Bill Hugo Bob Craig Classification...Director, Force and Infrastructure Cost Analysis Division OD (PA&E) Room 2D278, The Pentagon Washington, DC 20301 Dr. Craig College LMI John Wallace

  20. Proceedings of the 10th ASIS SIG/CR classification research workshop

    DEFF Research Database (Denmark)

    This volume is a working copy of the papers presented at the 9th ASIS SIG/CR workshop on classification research, held in Washington, DC, at the ASIS Annual Meeting on Sunday 31 October 1999. The contributions printed here are working papers, and thus, not necessarily in their final form...

  1. 77 FR 42297 - Meeting of the Ocean Research and Resources Advisory Panel

    Science.gov (United States)

    2012-07-18

    ... Consortium for Ocean Leadership, 1201 New York Avenue NW., 4th Floor, Washington, DC 2005. FOR FURTHER... discussions on ocean research, resource management, and other current issues in the ocean science and management communities. J.M. Beal, Lieutenant Commander, Office of the Judge Advocate General, U.S. Navy...

  2. DOE-Supported Researcher Is Co-Winner of 2006 Nobel Prize in Physics

    Science.gov (United States)

    DOE-Supported Researcher Is Co-Winner of 2006 Nobel Prize in Physics October 3, 2006 WASHINGTON, DC Space Flight Center for co-winning the 2006 Nobel Prize in Physics. "I offer my congratulations to with the 2006 Nobel Prize in Physics," Secretary Bodman said. "The groundbreaking work of

  3. dc Arc Fault Effect on Hybrid ac/dc Microgrid

    Science.gov (United States)

    Fatima, Zahra

    The advent of distributed energy resources (DER) and reliability and stability problems of the conventional grid system has given rise to the wide spread deployment of microgrids. Microgrids provide many advantages by incorporating renewable energy sources and increasing the reliability of the grid by isolating from the main grid in case of an outage. AC microgrids have been installed all over the world, but dc microgrids have been gaining interest due to the advantages they provide over ac microgrids. However the entire power network backbone is still ac and dc microgrids require expensive converters to connect to the ac power network. As a result hybrid ac/dc microgrids are gaining more attention as it combines the advantages of both ac and dc microgrids such as direct integration of ac and dc systems with minimum number of conversions which increases the efficiency by reducing energy losses. Although dc electric systems offer many advantages such as no synchronization and no reactive power, successful implementation of dc systems requires appropriate protection strategies. One unique protection challenge brought by the dc systems is dc arc faults. A dc arc fault is generated when there is a gap in the conductor due to insulation degradation and current is used to bridge the gap, resulting in an arc with very high temperature. Such a fault if it goes undetected and is not extinguished can cause damage to the entire system and cause fires. The purpose of the research is to study the effect of the dc arc fault at different locations in the hybrid ac/dc microgrid and provide insight on the reliability of the grid components when it is impacted by arc faults at various locations in the grid. The impact of dc arc fault at different locations on the performance of the PV array, wind generation, and constant power loads (CPL) interfaced with dc/dc converters is studied. MATLAB/Simulink is used to model the hybrid ac/dc microgrid and arc fault.

  4. DC electric springs with DC/DC converters

    DEFF Research Database (Denmark)

    Wang, Qingsong; Cheng, Ming; Jiang, Yunlei

    2016-01-01

    The concept of DC electric spring (DCES) was recently proposed to solve the stability issue caused by integrating intermittent renewable energy sources (RESs) to DC microgrids. In this paper, a new topology of DCES is proposed based on DC/DC converters. The proposed DCES consists of a bi-directio......The concept of DC electric spring (DCES) was recently proposed to solve the stability issue caused by integrating intermittent renewable energy sources (RESs) to DC microgrids. In this paper, a new topology of DCES is proposed based on DC/DC converters. The proposed DCES consists of a bi...... and/or constant discharging for batteries is adopted and four operating modes are analyzed as charging-positive, charging-negative, discharging-positive and discharging-negative modes. An additional mechanism for fast charging or fast discharging is also designed to secure normal operation...... of batteries. With the proposed DCES, the power fluctuations due to intermittent RESs can be passed to non-critical loads (NCLs) and batteries while power on critical loads (CLs) is kept stable. This is possibly the first attempt to design a DCES with only DC/DC converters. The performances of the proposed...

  5. 75 FR 12718 - United States Navy Restricted Area, Puget Sound, Naval Station Everett, Washington

    Science.gov (United States)

    2010-03-17

    ... . Follow the instructions for submitting comments. E-mail: david.b.olson@usace.army.mil . Include the..., Attn: CECW-CO (David B. Olson), 441 G Street, NW., Washington, DC 20314-1000. Hand Delivery/Courier... copy form. FOR FURTHER INFORMATION CONTACT: Mr. David Olson, Headquarters, Operations and Regulatory...

  6. Research on resistance characteristics of YBCO tape under short-time DC large current impact

    Science.gov (United States)

    Zhang, Zhifeng; Yang, Jiabin; Qiu, Qingquan; Zhang, Guomin; Lin, Liangzhen

    2017-06-01

    Research of the resistance characteristics of YBCO tape under short-time DC large current impact is the foundation of the developing DC superconducting fault current limiter (SFCL) for voltage source converter-based high voltage direct current system (VSC-HVDC), which is one of the valid approaches to solve the problems of renewable energy integration. SFCL can limit DC short-circuit and enhance the interrupting capabilities of DC circuit breakers. In this paper, under short-time DC large current impacts, the resistance features of naked tape of YBCO tape are studied to find the resistance - temperature change rule and the maximum impact current. The influence of insulation for the resistance - temperature characteristics of YBCO tape is studied by comparison tests with naked tape and insulating tape in 77 K. The influence of operating temperature on the tape is also studied under subcooled liquid nitrogen condition. For the current impact security of YBCO tape, the critical current degradation and top temperature are analyzed and worked as judgment standards. The testing results is helpful for in developing SFCL in VSC-HVDC.

  7. Superconductivity in Washington, D.C

    International Nuclear Information System (INIS)

    Ritter, D.

    1988-01-01

    The author provides insights into the federal government's activity in superconductors. He says the President's most important legislative proposal is a change in anti-trust laws to allow businesses to cooperate on joint production ventures. The President has also directed the Department of Energy, the Department of Commerce, the National Aeronautics and Space Administration, the National Science Foundation, and the Department of Defense to establish Superconductivity Research Centers to conduct research and disseminate information. The author says he thinks it is worthwhile to pursue the President's proposal for cooperation with Japan in superconductivity research and development. The author explains why he supports this and other key legislation related to superconductivity. He says if the United States does not do all that it can, as fast as it can, both domestically and internationally, the U.S. could lose the cutting edge of technological and commercial leadership in the latter 20th century and the 21st century. This is what superconductivity represents

  8. Improving Health, Social Welfare, and Human Development Through Women's Empowerment in Developing Countries: The 2016 Girl Up Leadership Summit, Washington, DC, USA.

    Science.gov (United States)

    Mendoza, Janel

    2016-01-01

    The United Nations Foundation's Girl Up campaign, an initiative dedicated to promoting the health, education, and leadership of adolescent girls in developing communities around the world, hosted its annual Girl Up Leadership Summit in Washington, DC from July 11-13, 2016. The summit welcomed more than 275 girl empowerment and women empowerment proponents to take part in leadership training, listen to and learn from influential figures like United Nations Deputy High Commissioner for Human Rights Kate Gilmore and Treasurer of the United States Rosie Rios, as well as engage in an official lobby day in the nation's capital. Topics discussed at the summit ranged from the issue of child marriage and sexual and reproductive health rights to intersectional feminism and the importance of the next generation of global girl advocates. The purpose and, later on, achievement of the conference was the development of such leaders and Girl Up representatives. Summit attendee and Girl Up Campus Leader Janel Mendoza shares her experience as a longstanding Girl Up supporter and reflects on the preeminent conversations held during and following the summit.

  9. Optical Computing Research.

    Science.gov (United States)

    1987-10-30

    1489-1496, 1985. 13. W.T. Welford and R. Winston, The Optics of Nonimaging Concentrators, Academic Press, New York, N.Y., 1978 (see Appendix A). 14. R.H...AD-fIB? Ŗ OPTICAL CONPIITINO RESEAIRCII(U STANFORD UlNIV CA STINFORD / ELECTRONICS LASS J N 0000W4 30 OCT 97 SMAFOSR-TR-S?-1635 RFOSR-96...Force Base ELEMENT NO. NO. NO. NO. Washington, DC 20332-6448 11. TITLE ,Include Security ClaaticaonUNCLASSIFIED 61102F 2305 B4 OPTICAL COMPUTING RESEARCH

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

    Science.gov (United States)

    Kraus, Robert; Myers, Ira; Baumann, Eric

    1990-01-01

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

  11. Research

    African Journals Online (AJOL)

    abp

    2017-10-19

    Oct 19, 2017 ... Methods: in October 2014, we interviewed a total of 430 women selling in the central market of Lusonga in Lubumbashi. Data on ..... Washington, DC: Academy for Educational Development, Food ... Accessed March 27, 2014.

  12. Federal research natural areas in Oregon and Washington: a guidebook for scientists and educators.

    Science.gov (United States)

    Jerry F. Franklin; Fredrick C. Hall; C. T. Dyrness; Chris. Maser

    1972-01-01

    A guide to the use of natural scientific preserves, Research Natural Areas, on Federal lands in Oregon and Washington. Detailed descriptions of physical and biological features, maps and photographs are provided for each of the 45 tracts presently reserved. Indices to Research Natural Areas by vegetation type and plant and mammalian species are included.

  13. Advanced DC/DC converters

    CERN Document Server

    Luo, Fang Lin

    2003-01-01

    DC/DC conversion techniques have undergone rapid development in recent decades. With the pioneering work of these authors, DC/DC converters have now moved into their sixth generation. This book offers a concise, practical presentation of DC/DC converters, summarizing the spectrum of conversion tecnologies and presentingmany new ideas and more than 100 new topologies. Nowhere else in the literature are DC/DC converters so logically sorted and systematically introduced, and nowhere else can readers find detailed information on prototype topologies that represent a major contribution to modern power engineering. More than 320 figures, 60 tables, and 500 formulae facilitate understand and provide precise data.

  14. Research

    African Journals Online (AJOL)

    abp

    2013-03-11

    Mar 11, 2013 ... From a practical point of view, apart from the data on age that are easily obtained from recorded ..... Washington D.C. : Academy for Educational Development 2003. ... learning: data mining, inference and prediction. New York:.

  15. How Can Improvements Be Made to the United States Metrorail System (With a Focus on the Washington Metropolitan Area Transit Authority Metrorail System) to Enhance Safety for Its Riders

    Science.gov (United States)

    2016-06-10

    on the rail system, and recommended improvements to improve the safety of the Metrorail system. These three influences show a holistic view of the...due to special events in the area to include Washington Redskins football , Washington National baseball, and other events held in the Washington, D.C...Station in Washington, DC. The accident resulted in nine people including the train operator were killed. Emergency response agencies reported

  16. Research-informed strategies to address educational challenges in a digitally networked world: the EDUsummIT 2013 action agenda

    NARCIS (Netherlands)

    Voogt, J.; Knezek, G.; Searson, M.; Lai, K.W.; Gibson, D.; Khaddage, F.; Mishra, P.; Laferriere, T.; Resta, P.; Fisser, P.; Albion, P.; Searson, M.; Ochoa, M.

    2014-01-01

    EduSummIT is a global community of policy-makers, researchers, and educators working together to move education into the digital age. EDUsummIT 2013 took place in Washington DC and resulted in an action agenda for researchers, policy makers and educators to take concrete steps to move education in

  17. A Unidirectional DC-DC Autotransformer for DC Grid Application

    Directory of Open Access Journals (Sweden)

    Meng Zhou

    2018-03-01

    Full Text Available Conventional unidirectional DC-DC converters for DC grid application employ DC-AC-DC two-stage conversion technology and suffer from high converter cost and power loss. To solve these issues, a unidirectional step-up DC-DC autotransformer (UUDAT and a unidirectional step-down DC-DC autotransformer (DUDAT are studied. The UUDAT and DUDAT are composed of a series connection of diode bridges and voltage source converters. Topologies of UUDAT and DUDAT are detailed. The harmonic and un-controllability issues are discussed. Control and possible application scenarios for UUDAT and DUDAT are depicted. DC fault isolation mechanism and the methods of dimensioning the voltage and power ratings of the components in UUDAT and DUDAT are studied. Extensive simulations on power system level and experiments on a UUDAT and DUDAT prototype verified their technical feasibility.

  18. 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.

  19. Brushless DC motor speed control strategy of simulation research

    Directory of Open Access Journals (Sweden)

    Xiang Wen

    2017-01-01

    Full Text Available In view of the brushless DC motor speed regulation problem, an ideal control strategy is designed. Through the model and analysis of Brushless DC motor, the mathematical model of the brushless DC motor is obtained. By comparing three control strategies of PID control strategy, fuzzy control strategy and fuzzy PID control strategy, PID controller, fuzzy controller and fuzzy PID controller are designed respectively for simulation test. The simulation results show that the fuzzy PID controller has good control effect.

  20. 78 FR 52786 - Notice Pursuant to the National Cooperative Research and Production Act of 1993-Members Of SGIP 2...

    Science.gov (United States)

    2013-08-26

    ...., Houston, TX; The University of Tokyo, Bunkyo-ku, Tokyo, JAPAN; U.S. Department of Energy, Washington, DC... Computer Solutions, Herndon, VA; Tri-County Electric Cooperative, Inc., Hooker, OK; ARC Technical Resources... Group, Inc., Boston, MA; Alliance for Telecommunications Industry Solutions (ATIS), Washington, DC; and...

  1. Isolated step-down DC -DC converter for electric vehicles

    Science.gov (United States)

    Kukovinets, O. V.; Sidorov, K. M.; Yutt, V. E.

    2018-02-01

    Modern motor-vehicle industrial sector is moving rapidly now towards the electricity-driving cars production, improving their range and efficiency of components, and in particular the step-down DC/DC converter to supply the onboard circuit 12/24V of electric vehicle from the high-voltage battery. The purpose of this article - to identify the best circuitry topology to design an advanced step-down DC/DC converters with the smallest mass, volume, highest efficiency and power. And this will have a positive effect on driving distance of electric vehicle (EV). On the basis of computational research of existing and implemented circuit topologies of step-down DC/DC converters (serial resonant converter, full bridge with phase-shifting converter, LLC resonant converter) a comprehensive analysis was carried out on the following characteristics: specific volume, specific weight, power, efficiency. The data obtained was the basis for the best technical option - LLC resonant converter. The results can serve as a guide material in the process of components design of the traction equipment for electric vehicles, providing for the best technical solutions in the design and manufacturing of converting equipment, self-contained power supply systems and advanced driver assistance systems.

  2. Improving Health, Social Welfare, and Human Development Through Women’s Empowerment in Developing Countries: The 2016 Girl Up Leadership Summit, Washington, DC, USA

    Science.gov (United States)

    Mendoza, Janel

    2016-01-01

    The United Nations Foundation’s Girl Up campaign, an initiative dedicated to promoting the health, education, and leadership of adolescent girls in developing communities around the world, hosted its annual Girl Up Leadership Summit in Washington, DC from July 11-13, 2016. The summit welcomed more than 275 girl empowerment and women empowerment proponents to take part in leadership training, listen to and learn from influential figures like United Nations Deputy High Commissioner for Human Rights Kate Gilmore and Treasurer of the United States Rosie Rios, as well as engage in an official lobby day in the nation’s capital. Topics discussed at the summit ranged from the issue of child marriage and sexual and reproductive health rights to intersectional feminism and the importance of the next generation of global girl advocates. The purpose and, later on, achievement of the conference was the development of such leaders and Girl Up representatives. Summit attendee and Girl Up Campus Leader Janel Mendoza shares her experience as a longstanding Girl Up supporter and reflects on the preeminent conversations held during and following the summit. PMID:28058195

  3. A One-Size-Fits-All HIV Prevention and Education Approach?: Interpreting Divergent HIV Risk Perceptions Between African American and East African Immigrant Women in Washington, DC Using the Proximate-Determinants Conceptual Framework.

    Science.gov (United States)

    De Jesus, Maria; Taylor, Juanita; Maine, Cathleen; Nalls, Patricia

    2016-02-01

    To date, there are very few comparative US studies and none in DC that distinguish between US-born and foreign-born black women to examine and compare their perceptions of HIV risk. This qualitative study, therefore, analyzes African American and East African women's perceptions of HIV risk in the Washington DC Metropolitan area, which has the highest AIDS rate in the United States. Forty in-depth, semistructured interviews and 10 cognitive interviews were conducted among a sample of 25 African American women and 25 East African born women between October 2012 and March 2013 to examine perceptions regarding HIV risk. The in-depth semistructured interviews were preceded by the cognitive interviews and accompanying survey. Study protocol was reviewed and approved by the American University Institutional Review Board. Adopting Boerma and Weir's Proximate Determinants conceptual framework to interpret the data, the results of the study demonstrate that African American and East African immigrant women have divergent perceptions of HIV risk. Although African American women ascribe HIV risk to individual-level behaviors and choices such as unprotected sex, East African women attribute HIV risk to conditions of poverty and survival. Study findings suggest that addressing HIV prevention and education among black women in DC will require distinct and targeted strategies that are culturally and community-centered to resonate with these different audiences.

  4. Hierarchical Control for Multiple DC-Microgrids Clusters

    DEFF Research Database (Denmark)

    Shafiee, Qobad; Dragicevic, Tomislav; Vasquez, Juan Carlos

    2014-01-01

    DC microgrids (MGs) have gained research interest during the recent years because of many potential advantages as compared to the ac system. To ensure reliable operation of a low-voltage dc MG as well as its intelligent operation with the other DC MGs, a hierarchical control is proposed in this p......DC microgrids (MGs) have gained research interest during the recent years because of many potential advantages as compared to the ac system. To ensure reliable operation of a low-voltage dc MG as well as its intelligent operation with the other DC MGs, a hierarchical control is proposed...

  5. Application and evaluation of the WRF-CMAQ modeling system to the 2011 DISCOVER-AQ Baltimore-Washington D.C. study

    Science.gov (United States)

    Appel, W.; Gilliam, R. C.; Pouliot, G. A.; Godowitch, J. M.; Pleim, J.; Hogrefe, C.; Kang, D.; Roselle, S. J.; Mathur, R.

    2013-12-01

    The DISCOVER-AQ project (Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality), is a joint collaboration between NASA, U.S. EPA and a number of other local organizations with the goal of characterizing air quality in urban areas using satellite, aircraft, vertical profiler and ground based measurements (http://discover-aq.larc.nasa.gov). In July 2011, the DISCOVER-AQ project conducted intensive air quality measurements in the Baltimore, MD and Washington, D.C. area in the eastern U.S. To take advantage of these unique data, the Community Multiscale Air Quality (CMAQ) model, coupled with the Weather Research and Forecasting (WRF) model is used to simulate the meteorology and air quality in the same region using 12-km, 4-km and 1-km horizontal grid spacings. The goal of the modeling exercise is to demonstrate the capability of the coupled WRF-CMAQ modeling system to simulate air quality at fine grid spacings in an urban area. Development of new data assimilation techniques and the use of higher resolution input data for the WRF model have been implemented to improve the meteorological results, particularly at the 4-km and 1-km grid resolutions. In addition, a number of updates to the CMAQ model were made to enhance the capability of the modeling system to accurately represent the magnitude and spatial distribution of pollutants at fine model resolutions. Data collected during the 2011 DISCOVER-AQ campaign, which include aircraft transects and spirals, ship measurements in the Chesapeake Bay, ozonesondes, tethered balloon measurements, DRAGON aerosol optical depth measurements, LIDAR measurements, and intensive ground-based site measurements, are used to evaluate results from the WRF-CMAQ modeling system for July 2011 at the three model grid resolutions. The results of the comparisons of the model results to these measurements will be presented, along with results from the various sensitivity simulations

  6. Research

    African Journals Online (AJOL)

    ebutamanya

    2 nov. 2015 ... Séraphin Nguefack1,2, Anderson Ngouo Tchiffo3, David Chelo2,4, ..... Stevenson et al [22], 38% des enfants IMC avaient un retard .... Krick J, Murphy-Miller P, Zeger S, Wright E. Pattern of growth ... Washington DC.2003.

  7. What to Buy? The Role of Director of Defense Research and Engineering (DDR&E) Lessons from the 1970s

    Science.gov (United States)

    2011-01-01

    M. Thorndike , “Antisubmarine Warfare in World War II,” OEG Report No. 51 (Washington, DC: Operations Evaluation Group, 1946). The authors were not...Sternhell, Charles M. and Alan M. Thorndike . “Antisubmarine Warfare in World War II.” OEG Report No. 51. Washington, DC: Operations Evaluation Group

  8. 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

  9. 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 s......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...

  10. Research & development and growth: A Bayesian model averaging analysis

    Czech Academy of Sciences Publication Activity Database

    Horváth, Roman

    2011-01-01

    Roč. 28, č. 6 (2011), s. 2669-2673 ISSN 0264-9993. [Society for Non-linear Dynamics and Econometrics Annual Conferencen. Washington DC, 16.03.2011-18.03.2011] R&D Projects: GA ČR GA402/09/0965 Institutional research plan: CEZ:AV0Z10750506 Keywords : Research and development * Growth * Bayesian model averaging Subject RIV: AH - Economic s Impact factor: 0.701, year: 2011 http://library.utia.cas.cz/separaty/2011/E/horvath-research & development and growth a bayesian model averaging analysis.pdf

  11. 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...

  12. Step-Up DC-DC converters

    DEFF Research Database (Denmark)

    Forouzesh, Mojtaba; Siwakoti, Yam P.; Gorji, Saman A.

    2017-01-01

    on the general law and framework of the development of next-generation step-up dc-dc converters, this paper aims to comprehensively review and classify various step-up dc-dc converters based on their characteristics and voltage-boosting techniques. In addition, the advantages and disadvantages of these voltage......DC-DC converters with voltage boost capability are widely used in a large number of power conversion applications, from fraction-of-volt to tens of thousands of volts at power levels from milliwatts to megawatts. The literature has reported on various voltage-boosting techniques, in which......-boosting techniques and associated converters are discussed in detail. Finally, broad applications of dc-dc converters are presented and summarized with comparative study of different voltage-boosting techniques....

  13. USING THE SEDIMENT QUALITY TRIAD (SQT) APPROACH TO ASSESS SEDIMENTARY CONTAMINATION IN THE ANACOSTIA RIVER, WASHINGTON

    Science.gov (United States)

    Using the Sediment Quality Triad (SQT) Approach to Assess Sedimentary Contamination in the Anacostia River, Washington, D.C. Velinsky, DJ*1, Ashley, JTF1,2, Pinkney, F.3, McGee, BL3 and Norberg-King, TJ.4 1Academy of Natural Sciences-PCER, Philadelphia, PA. 2Philadelphia Universi...

  14. A resonant dc-dc power converter assembly

    OpenAIRE

    Madsen, Mickey Pierre

    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 fo...

  15. 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.

  16. Diet and health: implications for reducing chronic disease risk

    National Research Council Canada - National Science Library

    1989-01-01

    ... National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1989 i Copyrightii NATIONAL ACADEMY PRESS 2101 CONSTITUTION AVENUE, NW WASHINGTON, DC 20418 NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the Nationa...

  17. 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.

  18. DC systems design and research of Hainan Changjiang nuclear power plant

    International Nuclear Information System (INIS)

    Jiang Qingshui; Wang Yuhan

    2014-01-01

    Hainan Changjiang nuclear power plant is different from the referent power plant, the DC and 220 V AC uninterrupted systems of the nuclear island have been changed since the control system use DCS. It has different design on DC systems, power supply, selectivity of breakers, capacity of equipments and layout. We optimize the design of DC systems at the basement of Fuqing and Fangjiashan project. These are good experiments for the three generation nuclear power project about DC systems design of ACP1000. (authors)

  19. A novel DC Magnetron sputtering facility for space research and synchrotron radiation optics

    DEFF Research Database (Denmark)

    Hussain, A.M.; Christensen, Finn Erland; Pareschi, G.

    1998-01-01

    A new DC magnetron sputtering facility has been build up at the Danish Space Research Institute (DSRI), specially designed to enable uniform coatings of large area curved optics, such as Wolter-I mirror optics used in space telescopes and curved optics used in synchrotron radiation facilities...

  20. Informal Science Educators' Views about Nature of Scientific Knowledge

    Science.gov (United States)

    Holliday, Gary M.; Lederman, Norman G.

    2014-01-01

    Publications such as "Surrounded by science: Learning science in informal environments" [Fenichel, M., & Schweingruber, H. A. (2010). Washington, DC: The National Academies Press] and "Learning science in informal environments: People, places, and pursuits" [National Research Council. (2009). Washington, DC: National…

  1. Applying a Qualitative Modeling Shell to Process Diagnosis: The Caster System.

    Science.gov (United States)

    1986-03-01

    of Leyden AFOSR Baltimore, MD 21204 Education Research Center Boiling AFB Boerhaavelaan 2 Washington, DC 20332 Dr. Davida Charney 2334 EN Leyden ...Charles Lewis Washington, DC 20002 Department of Psychology Faculteit Sociale Wetenschappen Dr. Kathleen McKeown Community College of Rijksuniversiteit

  2. Step-Up DC-DC converters

    DEFF Research Database (Denmark)

    Forouzesh, Mojtaba; Siwakoti, Yam P.; Gorji, Saman A.

    2017-01-01

    on the general law and framework of the development of next-generation step-up dc-dc converters, this paper aims to comprehensively review and classify various step-up dc-dc converters based on their characteristics and voltage-boosting techniques. In addition, the advantages and disadvantages of these voltage...

  3. Floating high step-down stacked dc-dc converter based on buck-boost cells

    NARCIS (Netherlands)

    Tibola, G.; Duarte, J.L.; Blinov, A.

    2015-01-01

    In some high power dc-dc applications, where high voltage is present, a converter with high step-down ratio is required in order to provide an isolated low power auxiliary supply. This requirement represents a challenge and many topologies are currently being researched. The analysis of a

  4. Integrating DC/DC Conversion with Possible Reconfiguration within Submodule Solar Photovoltaic Systems

    Science.gov (United States)

    Huang, Peter Jen-Hung

    This research first proposes a method to merge photovoltaic (PV) cells or PV panels within the internal components DC-DC converters. The purpose of this merged structure is to reconfigure the PV modules between series and parallel connections using high switching frequencies (hundreds of kHz). This leads to multi-levels of voltages and currents that become applied to the output filter of the converter. Further, this research introduces a concept of a switching cell that utilizes the reconfiguration of series and parallel connections in DC-DC converters. The switching occurs at high switching frequency and the switches can be integrated to be within the solar panels or in between the solar cells. The concept is generalized and applied to basic buck and boost topologies. As examples of the new types of converters: reconfigurable PV-buck and PV-boost converter topologies are presented. It is also possible to create other reconfigurable power converters: non-isolated and isolated topologies. Analysis, simulation and experimental verification for the reconfigurable PV-buck and PV-boost converters are presented extensively to illustrate proof of concept. Benefits and drawbacks of the new approach are discussed. The second part of this research proposes to utilize the internal solar cell capacitance and internal solar module wire parasitic inductances to replace the input capacitor and filter inductor in boost derived DC-DC converters for energy harvesting applications. High switching frequency (MHz) hard switched and resonant boost converters are proposed. Their analysis, simulation and experimental prototypes are presented. A specific proof-of-concept application is especially tested for foldable PV panels, which are known for their high internal wire inductance. The experimental converters successfully boost solar module voltage without adding any external input capacitance or filter inductor. Benefits and drawbacks of new proposed PV submodule integrated boost

  5. Electric and magnetic field reduction and research: A report to the Washington State Legislature

    International Nuclear Information System (INIS)

    Geissinger, L.G.; Waller, P.; Chartier, V.L.; Olsen, R.G.

    1993-01-01

    Increasingly, citizens of Washington State are expressing their concerns about possible adverse health effects of electric and magnetic fields (EMF) from electric utility power systems. A number of legislative proposals over the past several years have prompted governmental officials to evaluate available options for reducing electric and magnetic field strengths surrounding these systems (with a concentration on magnetic fields) or otherwise manage public exposure to power lines by increasing land use controls and setbacks for new development. Unsuccessful proposals brought before the Washington Legislature include 2 mG magnetic field limits for new transmission lines at the right-of-way edge; a temporary moratorium on transmission construction; requirements for providing public information on EMF; and expansion of the role of state governmental agencies in transmission siting and design. A successful Whatcom County initiative limits the voltage of new transmission to 115 kV in all but industrial land use zones, an action likely to have an unintended outcome of increasing magnetic fields in some areas. It is clear that better communication is needed about possible options for EMF management, costs and consequences, despite the fact scientific evidence on the existence of human health effects is inconclusive. This paper describes the work that Washington State undertook in 1990-92 in response to Engrossed Substitute Senate Bill 6771 establishing the Electric Transmission Research Needs Task Force. The Task Force was directed to report to the Legislature on possible exposure reduction methods; recommending engineering research that could lead to more effective approaches in the future

  6. Qualitative Student Models,

    Science.gov (United States)

    1986-05-01

    University of Leyden AFOSR Baltimore, MD 21204 Education Research Center Bol g Boerhaavelaan 2 asolling ADCDr. Davida Charney 2334 EN Leyden Washington, DC...Kotovsky Dr. Charles Lewis Washington, DC 20002Department of Psychology Faculteit Sociale Wetenschappen Dr. Kathleen McKeownCommunity College of

  7. Using and Evaluating Differential Modeling in Intelligent Tutoring and Apprentice Learning Systems.

    Science.gov (United States)

    1987-01-01

    University of Leyden AFOSR Baltimore, Yj 21204 Education Research Center Boiling AFB Boerhaavelaan 2 Washington, DC 20332Dr. Davida Charney 2334 EN Leyden ...Washington, DC * Dr. Kenneth Kotovsky Dr. Charles Lewis Department ot Psychology Faculteit Sociale Wetenschappen Dr. Kathleen McKeuwn Community College

  8. Opportunities for addressing laminated root rot caused by Phellinus sulphuracens in Washington's forests: A Report from the Washington State Academy of Sciences in cooperation with the Washington State Department of Natural Resources

    Science.gov (United States)

    R. James Cook; Robert L. Edmonds; Ned B. Klopfenstein; Willis Littke; Geral McDonald; Daniel Omdahl; Karen Ripley; Charles G. Shaw; Rona Sturrock; Paul Zambino

    2013-01-01

    This report from the Washington State Academy of Sciences (WSAS) is in response to a request from the Washington State Department of Natural Resources (DNR) to "identify approaches and opportunities ripe for research on understanding and managing root diseases of Douglas-fir." Similar to the process used by the National Research Council, the WSAS upon...

  9. 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

    ... Airworthiness Directives; McDonnell Douglas Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10... amends Sec. 39.13 by adding the following new AD: 2010-09-12 McDonnell Douglas Corporation: Amendment 39... to McDonnell Douglas Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A...

  10. Excellence Initiatives to Establish World-Class Universities: Evaluation of Recent Experiences

    OpenAIRE

    Jamil Salmi; Isak Froumin

    2013-01-01

    Jamil Salmi, Ph. D., coordinator of the World Banks tertiary education program (NW, Washington, D.C., United States), member of the International Advisory Panel, National Research University -Higher School of Economics, Moscow, Russian Federation. Email: Address: The World Bank Institute, 1818 H Street, NW, Washington, D.C. 20433, United States.Isak Froumin, Ped.D., Professor, Director of Research and Development at the Education Institute, National Research Unive...

  11. 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.

  12. Priority research areas to accelerate the development of practical ultraconductive copper conductors

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dominic F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Burwell, Malcolm [International Copper Association, Washington, DC (United States); Stillman, H. [International Copper Association, Washington, DC (United States)

    2015-09-01

    This report documents the findings at an Ultraconductive Copper Strategy Meeting held on March 11, 2015 in Washington DC. The aim of this meeting was to bring together researchers of ultraconductive copper in the U.S. to identify and prioritize critical non-proprietary research activities that will enhance the understanding in the material and accelerate its development into practical conductors. Every effort has been made to ensure that the discussion and findings are accurately reported in this document.

  13. A Biogeochemical and Spectral Analysis of Vegetation Affected by External Abiotic Agents: Results of an Investigation from Kitsap County, Washington

    Science.gov (United States)

    1990-12-01

    delineated using a remote sensing tech- nique, as proposed, the method may provide a faster and more economic means for environmental assessments and for...NC," Economic Geology, vol 78, no. 4, 1983, pp 605-617. Palazzo, A.J., and Leggett, D.C. (1986). Effect and disposition of TNT in a terrestrial...CECOM R&D Tech Lib. Ft Monmouth. NJ; CEHSC-FU-N (Krajewski). Ft Belvoir. VA: Ch of Engrs. DAEN-C’WE-M. Washington. DC:, Ch of Engrs. DAEN- MPU

  14. 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…

  15. Processes Controlling CH2O Over the Baltimore/Washington DC Metropolitan Region: A Box Model Analysis Using Data from DISCOVER-AQ

    Science.gov (United States)

    Olson, J. R.; Crawford, J. H.; Fried, A.; Wisthaler, A.; Weinheimer, A. J.; Barrick, J. D.; Diskin, G. S.; Duncan, B. N.; Mikoviny, T.

    2012-12-01

    The first deployment for NASA's Earth Venture campaign DISCOVER-AQ (Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality) took place over the Baltimore/Washington DC region during July of 2011. Observations of CH2O in the lowest kilometer (pressure-altitude) indicate that median concentrations can vary day to day by as much as 5 ppbv. Further, variability within a single day can correlate with a number of species, including H2O, temperature, isoprene, and/or CO. The NASA Langley photochemical box model is used to examine the dominant budget terms for CH2O during DISCOVER-AQ and to diagnose the drivers of the CH2O variability. Modeling results show that the source of CH2O is largely dominated by isoprene. However, the variability of CH2O within single flight days is rarely directly correlated to isoprene. Rather, most often, CH2O variability is correlated to the oxidative capacity of the atmosphere, defined by OH and driven by OH precursors such as H2O, O3 photolysis rates, and NO. Sensitivity model runs where isoprene is held constant to daily medians show excellent ability to predict both the overall CH2O concentration (dominated by isoprene) and the variability of CH2O throughout a day (driven by variations in oxidative capacity).

  16. The Legacy of the Georgetown College Observatory (D.C.)

    Science.gov (United States)

    Caron, Laura; Maglieri, Grace; Seitzer, Patrick

    2018-01-01

    Founded in 1841 as part of a nascent worldwide network of Jesuit-run astronomical observatories, the Georgetown College Observatory of Georgetown University in Washington, D.C. has been home to more than 125 years of astronomical research, from Father Curley’s calculations of the latitude and longitude of D.C. to Father McNally’s award-winning solar eclipse photography. But the impact of the Georgetown astronomy program was not limited to the observatory itself: it reached much further, into the local community and schools, and into the lives of everyone involved. This was never more apparent than under the directorship of Father Francis J Heyden, S.J., who arrived at Georgetown after World War II and stayed for almost three decades. He started a graduate program with over 90 graduates, hosting student researchers from local high schools and colleges, teaching graduate and undergraduate astronomy courses, and speaking at schools in the area, all while simultaneously managing Georgetown’s student radio station and hosting astronomical conferences on campus. Father Heyden’s research focused mainly on solar eclipses for geodetic purposes and planetary spectroscopy. But perhaps even more than research, Father Heyden dedicated his time and energy to the astronomy students, the notable of which include Vera Rubin, John P. Hagen of Project Vanguard, and a generation of Jesuit astronomers including Martin McCarthy, George Coyne, and Richard Boyle. Following the closure of the astronomy department in 1972, Father Heyden returned to Manila, where he had begun his astronomical career, to become Chief of the Solar Division at the Manila Observatory. His dedication to his work and to students serves as an inspiration for academic researchers across fields, and for the Georgetown University Astronomical Society, which, even in the absence of a formal astronomy program at Georgetown, continues his work in education and outreach today. In 1987, almost 150 years after its

  17. 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.

  18. 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. PMID:26824489

  19. Cost-based droop scheme for DC microgrid

    DEFF Research Database (Denmark)

    Nutkani, Inam Ullah; Wang, Peng; Loh, Poh Chiang

    2014-01-01

    voltage level, less on optimized operation and control of generation sources. The latter theme is perused in this paper, where cost-based droop scheme is proposed for distributed generators (DGs) in DC microgrids. Unlike traditional proportional power sharing based droop scheme, the proposed scheme......-connected operation. Most importantly, the proposed scheme can reduce overall total generation cost in DC microgrids without centralized controller and communication links. The performance of the proposed scheme has been verified under different load conditions.......DC microgrids are gaining interest due to higher efficiencies of DC distribution compared with AC. The benefits of DC systems have been widely researched for data centers, IT facilities and residential applications. The research focus, however, has been more on system architecture and optimal...

  20. Washington State University Algae Biofuels Research

    Energy Technology Data Exchange (ETDEWEB)

    chen, Shulin [Washington State Univ., Pullman, WA (United States). Dept. of Biological Systems Engineering; McCormick, Margaret [Targeted Growth, Inc., Seattle, WA (United States); Sutterlin, Rusty [Inventure Renewables, Inc., Gig Harbor, WA (United States)

    2012-12-29

    The goal of this project was to advance algal technologies for the production of biofuels and biochemicals by establishing the Washington State Algae Alliance, a collaboration partnership among two private companies (Targeted Growth, Inc. (TGI), Inventure Chemicals (Inventure) Inc (now Inventure Renewables Inc) and Washington State University (WSU). This project included three major components. The first one was strain development at TGI by genetically engineering cyanobacteria to yield high levels of lipid and other specialty chemicals. The second component was developing an algal culture system at WSU to produce algal biomass as biofuel feedstock year-round in the northern states of the United States. This system included two cultivation modes, the first one was a phototrophic process and the second a heterotrophic process. The phototrophic process would be used for algae production in open ponds during warm seasons; the heterotrophic process would be used in cold seasons so that year-round production of algal lipid would be possible. In warm seasons the heterotrophic process would also produce algal seeds to be used in the phototrophic culture process. Selected strains of green algae and cyanobacteria developed by TGI were tested in the system. The third component was downstream algal biomass processing by Inventure that included efficiently harvesting the usable fuel fractions from the algae mass and effectively isolating and separating the usable components into specific fractions, and converting isolated fractions into green chemicals.

  1. Family of multiport bidirectional DC-DC converters

    NARCIS (Netherlands)

    Tao, H.; Kotsopoulos, A.; Duarte, J.L.; Hendrix, M.A.M.

    2006-01-01

    Multiport DC-DC converters are of potential interest in applications such as generation systems utilising multiple sustainable energy sources. A family of multiport bidirectional DC-DC converters derived from a general topology is presented. The topology shows a combination of DC-link and magnetic

  2. Research on DC-RF superconducting photocathode injector for high average power FELs

    International Nuclear Information System (INIS)

    Zhao Kui; Hao Jiankui; Hu Yanle; Zhang Baocheng; Quan Shengwen; Chen Jiaer; Zhuang Jiejia

    2001-01-01

    To obtain high average current electron beams for a high average power Free Electron Laser (FEL), a DC-RF superconducting injector is designed. It consists of a DC extraction gap, a 1+((1)/(2)) superconducting cavity and a coaxial input system. The DC gap, which takes the form of a Pierce configuration, is connected to the 1+((1)/(2)) superconducting cavity. The photocathode is attached to the negative electrode of the DC gap. The anode forms the bottom of the ((1)/(2)) cavity. Simulations are made to model the beam dynamics of the electron beams extracted by the DC gap and accelerated by the superconducting cavity. High quality electron beams with emittance lower than 3 π-mm-mrad can be obtained. The optimization of experiments with the DC gap, as well as the design of experiments with the coaxial coupler have all been completed. An optimized 1+((1)/(2)) superconducting cavity is in the process of being studied and manufactured

  3. Aircraft Accident Report; Uncontrolled Impact with Terrain, Fine Airlines Flight 101, Douglas DC-8-61, N27UA, Miami, Florida, August 7, 1997

    Science.gov (United States)

    1998-06-16

    Transcolombiana de Carga ATI Air Transport International ATOS Air Transportation Oversight System ATP airline transport pilot CAM cockpit area microphone...495,000 fine against Aero Transcolombiana de Carga (ATC) for operating a DC-8-51 "over the weight limits set forth in its FAA-approved flight manual...PB98-910402 NTSB/AAR-98/02 DCA97MA059 NATIONAL TRANSPORTATION SAFETY BOARD WASHINGTON, D.C. 20594 AIRCRAFT ACCIDENT REPORT c>C== UNCONTROLLED IMPACT

  4. Design and Testing of Boost Type DC/DC Converter for DC Motor Control Applications

    OpenAIRE

    Samman, Faizal Arya; Akil, Yusri Syam; Noor, Nirwan A.

    2017-01-01

    in The Proceeding of The 2nd International Symposium on Smart Material and Mechatronics 2015 This paper presents the design and testing of a boost type DC/DC converter circuit, which can be used for DC motor control applications. The Boost converter is designed using DC chopper and DC chopper cascade configurations. The experimental setup was made by connecting the boost converter circuit with four types of DC motor, i.e. self-excited DC motor shunt, series, compound and separately exci...

  5. The challenges to gender integration in the career fire services: a comparative case study of men in nursing

    Science.gov (United States)

    2017-03-01

    pdf. 191 David F. Burrelli, Women in the Armed Forces (CRS Report No. 92008) ( Washington , DC: Congressional Research Service, 1998), 1, https...IB92008) Washington , DC: Congressional Research Service, 1998. https://www.hsdl.org/?view&did=718051. Carreiras, Helena. Gender and the Military: Women ...GENDER INTEGRATION IN THE CAREER FIRE SERVICES: A COMPARATIVE CASE STUDY OF MEN IN NURSING by Anna L. Schermerhorn-Collins March 2017

  6. 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

    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...... 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...

  7. 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...

  8. IGBT Based DC/DC Converter

    Directory of Open Access Journals (Sweden)

    M. Akherraz

    1997-12-01

    Full Text Available This paper presents an in-depth analytical and experimental investigation of an indirect DC-DC converter. The DC-AC conversion is a full bridge based on IGBT power modules, and the AC-DC conversion is done via a high  frequency AC link and a first diode bridge. The AC link, which consists of snubbing capacitors and a variable air-gap transformer, is analytically designed to fulfill Zero Voltage commutation requirement. The proposed converter is simulated using PSPICE and a prototype is designed built and tested in the laboratory. PSPICE simulation and experimental results are presented and compared.

  9. 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...

  10. NASA/DoD Aerospace Knowledge Diffusion Research Project. Report Number 6. The Relationship between the Use of U.S. Government Technical Reports by U.S. Aerospace Engineers and Scientists and Selected Institutional and Sociometric Variables

    Science.gov (United States)

    1991-01-01

    Peter R.; James D. Schriner; Bettie F. Farace ; and Richard V. Farace . The Assessment of NASA Technical Information. NASA CR-181367. Washington, DC... Farace ; and Richard V. Farace . The Assessment of NASA Technical Information. NASA CR-181367. Washington, DC: National Aeronautics and Space

  11. Three new DC-to-DC Single-Switch Converters

    Directory of Open Access Journals (Sweden)

    Barry W. Williams

    2017-06-01

    Full Text Available This paper presents a new family of three previously unidentified dc-to-dc converters, buck, boost, and buck-boost voltage-transfer-function topologies, which offer advantageous transformer coupling features and low capacitor dc voltage stressing. The three single-switch, single-diode, converters offer the same features as basic dc-to-dc converters, such as the buck function with continuous output current and the boost function with continuous input current. Converter time-domain simulations and experimental results (including transformer coupling support and extol the dc-to-dc converter concepts and analysis presented.

  12. Proceedings of the 1993 Particle Accelerator Conference Held in Washington, DC on May 17-20, 1993. Volume 2

    Science.gov (United States)

    1993-05-20

    Shapiro, S. Bethke, 0. Chamberlain, R. Fuzesy, M. Kowitt, D. Pripstein, B. Schumm, H. Steiner , M. Zolotorev, LBL; P. Rowson, Columbia; D. Blockus, H...Conference Proceedings, March 1989. 2. Rudolf P. Sevems, and Gordon E. Bloom, "Modern DC- to-DC Switchmode Power Converter Circuits," Van Nostrand...R. E. 2471 Steiner , H. 2172 Sytnikov, V. 2769 Thevenot, M. 670, 697 Steinhauer. L. C. 2564, 2581, Thiagarajan, V. 3372 2614 Thieberger, P. 3178

  13. Effects of Appraisal Salience on Immediate and Memory-Based Judgments.

    Science.gov (United States)

    1984-03-01

    Hiypothesis I lias found. The arioiint of informiation (frortf’-t.1 y rocalln 1 ’torroa( -? Jini ficantil,/ if tot- a onc-lir’ roten . ionn i ntrrval . This...Personnel Mqt. GAO Office of Planning and Evol. Washington, DC 20548 Research Mgt. Division 1900 E. Street, N.W. Washington, DC 20415 National

  14. 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

    ... Airworthiness Directives; McDonnell Douglas Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10... adding the following new AD: 2010-20-14 McDonnell Douglas Corporation: Amendment 39-16449. Docket No. FAA... the airplanes identified in paragraphs (c)(1) and (c)(2) of this AD. (1) McDonnell Douglas Corporation...

  15. 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

    ...-0672; Directorate Identifier 2010-NM-047-AD] RIN 2120-AA64 Airworthiness Directives; McDonnell Douglas...: McDonnell Douglas Corporation: Docket No. FAA-2010-0672; Directorate Identifier 2010-NM-047-AD. Comments Due... applies to McDonnell Douglas Corporation Model DC- 10-10, DC-10-10F, DC-10-30, DC-10-30F (KDC-10), DC-10...

  16. 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

  17. 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

    ...-0032; Directorate Identifier 2009-NM-213-AD] RIN 2120-AA64 Airworthiness Directives; McDonnell Douglas...: McDonnell Douglas Corporation: Docket No. FAA-2010-0032; Directorate Identifier 2009-NM-213-AD. Comments Due... applies to McDonnell Douglas Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A...

  18. 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

    ... Airworthiness Directives; McDonnell Douglas Corporation Model DC- 8-31, DC-8-32, DC-8-33, DC-8-41, DC-8-42, and... to all of the McDonnell Douglas Corporation airplanes identified above. The existing AD currently... the following new airworthiness directive (AD): 2010-21-03 McDonnell Douglas Corporation: Amendment 39...

  19. Application research of power allocation based on Buck circuit in DC microgrid

    OpenAIRE

    Wang Zihao; Zhou Mingyu

    2017-01-01

    In a traditional DC microgrid, the power sharing control strategy has been always used in the distributed power converters, resulting in not making outer power allocation arbitrarily. In order to solve the power output allocation problem of wind power in DC microgrid, the intelligent Buck circuit based on PI algorithm and the load current feed-forward method was used to realize the arbitrary regulation of the output power of the wind power in the DC microgrid system. Compared with traditional...

  20. Multi Bus DC-DC Converter in Electric Hybrid Vehicles

    Science.gov (United States)

    Krithika, V.; Subramaniam, C.; Sridharan, R.; Geetha, A.

    2018-04-01

    This paper is cotncerned with the design, simulation and fabrication of the prototype of a Multi bus DC- DC converter operating from 42V DC and delivering 14V DC and 260V DC. As a result, three DC buses are interconnected through a single power electronic circuitry. Such a requirement is energized in the development of a hybrid electric automobile which uses the technology of fuel cell. This is implemented by using a Bidirectional DC-DC converter configuration which is ideally suitable for multiple outputs with mutual electrical isolation. For the sake of reduced size and cost of step-up transformer, selection of a high frequency switching cycle at 10 KHz was done.

  1. 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...

  2. 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.

  3. 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.

  4. Biochemical Systematics and Population Genetic Structure of Anopheles Pseudopunctipennis, Vector of Malaria in Central and South America

    Science.gov (United States)

    1995-01-01

    Biosystematics Unit, Department of Entomology, Walter Reed Army Institute of Research, Washington, District of Columbia; Laboratorio de Entomologia ...Entomology, Walter Reed Army Institute of Research, Washington, DC 20307-5 100. Ildefonso Fernandez-Sa- las, Laboratorio de Entomologia Medica

  5. Reliability of capacitors for DC-link applications - An overview

    DEFF Research Database (Denmark)

    Wang, Huai; Blaabjerg, Frede

    2013-01-01

    DC-link capacitors are an important part in the majority of power electronic converters which contribute to cost, size and failure rate on a considerable scale. From capacitor users' viewpoint, this paper presents a review on the improvement of reliability of DC-link in power electronic converters...... from two aspects: 1) reliability-oriented DC-link design solutions; 2) conditioning monitoring of DC-link capacitors during operation. Failure mechanisms, failure modes and lifetime models of capacitors suitable for the applications are also discussed as a basis to understand the physics......-of-failure. This review serves to provide a clear picture of the state-of-the-art research in this area and to identify the corresponding challenges and future research directions for capacitors and their DC-link applications....

  6. Guest Editorial Special Issue on Structured DC Microgrids

    DEFF Research Database (Denmark)

    Guerrero, Josep M.; Tan, Don F. D.

    2017-01-01

    With the development of dc coupled devices, such as photovoltaic generations, batteries, supercapacitors, LEDs, computers, and electronics equipment, low-voltage dc distribution networks, structured dc microgrids are emerging as a natural platform to integrate renewable energy sources. However...... in either series/parallel, forming a number of dc busses with different voltage levels. Recently, with the advance of new dc power technologies, several ongoing standards, alliances, and initiatives are bringing the possibility of developing future homes, offices, buildings, campuses, datacenters, ships......, satellites, aircrafts, and other electrical power systems to operate totally or dominantly in dc. Research is being carried out in both the system and component levels of modeling, control, and stability of structured dc microgrids. New high-efficiency topologies and protections are also key nontrivial...

  7. Superconducting energy stabilizer with charging and discharging DC-DC converters

    International Nuclear Information System (INIS)

    Kim, S.H.; Kostecki, E.L.; DeWinkel, C.C.

    1992-01-01

    This patent describes a superconducting energy stabilizer having multiple load connections and employing DC-DC conversion for storing energy in a superconducting inductive energy storage device having a first end and a second end, and for releasing the stored energy from the superconducting inductive energy storage device to a load or loads or to a utility or an industrial electrical distribution system, the superconducting energy stabilizer having multiple load connections and employing DC-DC conversion. It comprises: energy storage cell means for supplying energy to the load, discharging DC-DC converter means for releasing energy from the superconducting inductive energy storage device to the energy storage cell means, the discharging DC-DC converter means having input terminals, output terminals, and a discharging control line means for carrying signals controlling the operation of the discharging DC-DC converter means, one of the input terminals of the discharging DC-DC converter means coupled to the first end of the superconducting energy storage device

  8. Restoring the Lost Rivers of Washington: Can a city's hydrologic past inform its future?

    OpenAIRE

    Millay, Curtis A.

    2005-01-01

    Washington, D.C., like many older U.S. cities, suffers the woes of rapid urbanization and aging infrastructure. The cityâ s combined sewer and stormwater system dumps millions of gallons of raw sewage into the Anacostia and Potomac Rivers over 70 times annually during significant rain events. While many groups, both public and private, attempt to clean the river, billions of dollars are still necessary over several years to remedy the combined sewer overfl ow (CSO) problem alone. Current pla...

  9. Milliwatt dc/dc Inverter

    Science.gov (United States)

    Mclyman, C. W.

    1983-01-01

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

  10. 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

    ... Airworthiness Directives; McDonnell Douglas Corporation Model DC- 10-10, DC-10-10F, DC-10-30, DC-10-30F (KDC-10... following new airworthiness directive (AD): 2010-21-13 McDonnell Douglas Corporation: Amendment 39-16473... November 18, 2010. Affected ADs (b) None. Applicability (c) This AD applies to McDonnell Douglas...

  11. 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

    ...-1044; Directorate Identifier 2010-NM-033-AD] RIN 2120-AA64 Airworthiness Directives; McDonnell Douglas..., 2007) and adding the following new AD: McDonnell Douglas Corporation: Docket No. FAA-2010-1044.... Applicability (c) This AD applies to all McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-15, DC...

  12. 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....

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  14. 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.

  15. Deadbeat control of power leveling unit with bidirectional buck/boost DC/DC converter

    OpenAIRE

    Hamasaki, Shin-ichi; Mukai, Ryosuke; Yano, Yoshihiro; Tsuji, Mineo

    2014-01-01

    As a distributed generation system increases, a stable power supply becomes difficult. Thus control of power leveling (PL) unit is required to maintain the balance of power flow for irregular power generation. The unit is required to respond to change of voltage and bidirectional power flow. So the bidirectional buck/boost DC/DC converter is applied for the control of PL unit in this research. The PL unit with Electric double-layer capacitor (EDLC) is able to absorb change of power, and it is...

  16. Intelligent DC Microgrid Living Laboratories - A Chinese-Danish Cooperation Project

    DEFF Research Database (Denmark)

    Diaz, Enrique Rodriguez; Su, Xiaoling; Savaghebi, Mehdi

    2015-01-01

    This paper presents a research project focus on the development of future intelligent direct-current (DC) microgrids which is being deployed for highly efficient integration of distributed generation and modern electronic loads. The project is based on the collaboration between research institutes...... in China and Denmark, aiming to explore the different aspects of DC microgrids: design, modelling, control, coordination, communications and management. In addition, a future Living Laboratory will also be integrated into the Intelligent DC Microgrids Laboratory, which will serve as demonstration facility...... for low voltage direct-current (LVDC) distribution systems. Research is carried out in both Intelligent DC Microgrid Laboratories, focused on industry in China and residential applications in Denmark....

  17. 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.

  18. Enhancement of the Monet/Atonet Washington DC Network

    National Research Council Canada - National Science Library

    Jackel, Janet

    2003-01-01

    ... Internet research networks. The report also describes research in the use of hierarchical multiplexing approaches for more efficient use of multi-wavelength networks and enhancements to the MONET Network Control & Management System...

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

    OpenAIRE

    Liwen Pan; Chengning Zhang

    2016-01-01

    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 m...

  20. 76 FR 8357 - Biological and Environmental Research Advisory Committee

    Science.gov (United States)

    2011-02-14

    ..., 2011, 9 a.m. to 12 p.m. ADDRESSES: Omni Shoreham Hotel, 2500 Calvert Street, NW., Washington, DC 20008... Response Joint Genome Institute Update and ARM review outbrief 2012 Budget briefing New Business Public...

  1. List of U.S. Army Research Institute Research and Technical Publications for Public Release/Unlimited Distribution, Fiscal Year 2009

    Science.gov (United States)

    2010-05-01

    Internet Delivery of Captains in Command Training: Administrator’s Guide Scott Shadrick, Tony Fullen, & Brian Crabb. June 2009. (ADA507719) In...Engineering Technical Advisory Group, Meeting 60, Washington, DC. Kilcullen, R., Tremble, T., Babin, N., Robbins , J., & Russell, T. (2009, August

  2. 77 FR 24369 - Standard Instrument Approach Procedures, and Takeoff Minimums and Obstacle Departure Procedures...

    Science.gov (United States)

    2012-04-24

    ..., VOR-A, Amdt 7 Washington, DC, Ronald Reagan Washington National, COPTER ILS OR LOC/DME RWY 1, Amdt 1 Washington, DC, Ronald Reagan Washington National, ILS OR LOC/DME RWY 1, ILS RWY 1 (SA CAT I), ILS RWY 1 (CAT II), Amdt 41 Washington, DC, Ronald Reagan Washington National, RNAV (RNP) RWY 1, Amdt 1 Washington...

  3. Full range ZVS DC-DC converter

    International Nuclear Information System (INIS)

    Upadhyay, Rinki; Badapanda, M.K.; Hannurkar, P.R.

    2011-01-01

    A 500 V, 24 Amp DC-DC converter with digital signal processor (DSP) based control and protection has been designed, fabricated and tested. Its power circuit consists of IGBT based single phase inverter bridge, ferrite transformer and diode rectifier. All IGBTs in the inverter bridge are operated in zero voltage switching (ZVS) mode to minimize switching losses thereby increasing the efficiency of the converter significantly. The efficiency of this converter is measured to be greater than 97% at full load. In a conventional full bridge inverter, typically ZVS is achieved under full load condition while at light load ZVS is lost. An auxiliary LC circuit has been intentionally incorporated in this converter to achieve ZVS even at light loaded conditions. Detailed simulation of the converter circuit is carried out and crucial waveforms have been presented in this paper. Microchip make dsPIC30F2020 DSP is employed to provide phase shifted PWMs to IGBTs in the inverter bridge. All the crucial parameters are also monitored by this DSP and in case of any unfavorable conditions, the converter is tripped off. Suitable experiments were carried out in this DC-DC converter under different loaded conditions and a close match between the simulated and experimental results were obtained. Such DC-DC converters can be connected in series or parallel for the development of solid state modular power supplies for various applications. (author)

  4. Biomechanical Modeling of the Human Head

    Science.gov (United States)

    2017-10-03

    Naval Research Laboratory Washington, DC 20375-5320 DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. October 3...Laboratory 4555 Overlook Avenue, SW Washington, DC 20375-5320 NRL/FR/6350--17-10,304 DISTRIBUTION STATEMENT A: Approved for public release; distribution is... generating a calibrated constitutive model. First, a constitutive model form that can sufficiently capture the phenomena that occur in the experimental data is

  5. Protecting the Homeland: The Importance of Counter-Illicit Trafficking to Prevent an Attack with Weapons of Mass Destruction

    Science.gov (United States)

    2013-03-01

    Congressional Research Service, U.S. International Borders: Brief Facts, Janice Cheryl Beaver , RS21729 (Washington, DC: Government Printing Office, November 9...and the opportunity to utilize the breadth of smuggling options for transportation. The commercial prevalence of radiological material and the...Janice Cheryl Beaver . RS21729. Washington, DC: Government Printing Office November 9, 2006. http://www.fas.org/sgp/crs/misc/RS21729.pdf (accessed

  6. Medical and Non-Medical Predictors of Disability Discharge Disposition for Navy Personnel with a Back Problem: A Focus on Entitlement

    Science.gov (United States)

    1988-03-28

    Washington D.C. 20350-1000. Stryker, S., & Gottlieb, A. (1981). Attribution theory and symbolic interactionism : A comparison. In J.H. Howes, W...ERFORMIING ORGANIZATION 6b OFFiCE SYMBOL 7a NAME OF MONITORING ORGANIZATION (If applicable) Naval Health Research Center 40 Commander, Naval Medical Command...Washington, DC 20372 ea NAME OF FUNDING/SPONSORING Bb OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ORGANIZATION Naval Medical (If applicable

  7. Siting Background Towers to Characterize Incoming Air for Urban Greenhouse Gas Estimation: A Case Study in the Washington, DC/Baltimore Area

    Science.gov (United States)

    Mueller, K.; Yadav, V.; Lopez-Coto, I.; Karion, A.; Gourdji, S.; Martin, C.; Whetstone, J.

    2018-03-01

    There is increased interest in understanding urban greenhouse gas (GHG) emissions. To accurately estimate city emissions, the influence of extraurban fluxes must first be removed from urban greenhouse gas (GHG) observations. This is especially true for regions, such as the U.S. Northeastern Corridor-Baltimore/Washington, DC (NEC-B/W), downwind of large fluxes. To help site background towers for the NEC-B/W, we use a coupled Bayesian Information Criteria and geostatistical regression approach to help site four background locations that best explain CO2 variability due to extraurban fluxes modeled at 12 urban towers. The synthetic experiment uses an atmospheric transport and dispersion model coupled with two different flux inventories to create modeled observations and evaluate 15 candidate towers located along the urban domain for February and July 2013. The analysis shows that the average ratios of extraurban inflow to total modeled enhancements at urban towers are 21% to 36% in February and 31% to 43% in July. In July, the incoming air dominates the total variability of synthetic enhancements at the urban towers (R2 = 0.58). Modeled observations from the selected background towers generally capture the variability in the synthetic CO2 enhancements at urban towers (R2 = 0.75, root-mean-square error (RMSE) = 3.64 ppm; R2 = 0.43, RMSE = 4.96 ppm for February and July). However, errors associated with representing background air can be up to 10 ppm for any given observation even with an optimal background tower configuration. More sophisticated methods may be necessary to represent background air to accurately estimate urban GHG emissions.

  8. Simulation analysis of cascade controller for DC-DC bank converter

    International Nuclear Information System (INIS)

    Mahar, M.A.; Abro, M.R.; Larik, A.S.

    2009-01-01

    Power electronic converters are periodic variable structure systems due to their switched operation. During the last few decades several new dc-dc converter topologies have emerged. Buck converter being simple in topology, has recently drawn attraction of many researchers. Basically, a buck converter is highly underdamped system. In order to overcome the developed oscillations in output of this converter, various control techniques have been proposed. However, these techniques are fraught with many drawbacks. This paper focus on a cascade controller based buck topology. Steady state analysis is given in this paper which shows output voltage and inductor current in detail. Dynamic analysis for line and load variation is also presented. The buck topology is implemented and simulated in MATLAB/Simulink. The simulated results are presented. (author)

  9. Educator Supply and Demand in Washington State. 2004 Report

    Science.gov (United States)

    Lashway, Larry; Maloney, Rick; Hathaway, Randy; Bryant, B. J.

    2005-01-01

    This report describes the findings of the third Educator Supply and Demand Research study in the State of Washington. The intent of these Washington studies is to provide data to inform and shape decisions and activities in the following ways: (1) Provide useful information for educational policymakers, including the legislature, the State Board…

  10. 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.

  11. 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…

  12. 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.

  13. Retrospective evaluation of early and aggressive decompressive craniectomy (DC) for severe head injury. Was that DC necessary?

    International Nuclear Information System (INIS)

    Hagihara, Yasushi; Ueno, Masato; Mizushima, Yasuaki; Matsuoka, Tetsuya

    2011-01-01

    Recently, decompressive craniectomy (DC) for refractory intracranial hypertension (IH) has been widely reevaluated, and many researchers support the advantages of early and aggressive DC in the management of severe head trauma. We too applied DC in the early stages of IH, and confirmed its favorable results compared to those of the standard treatment. In patients with evacuate masses (EM), DC was determined based on the intraoperative condition of the brain parenchyma; in those without EM, intracranial pressure (ICP) ≥30 mmHg was considered the criterion for DC. However, in some cases, the expected brain edema (BE) was absent after DC, and DC seemed unnecessary on retrospection. Here, the effectiveness of DC performed at our hospital and its predictive factors were investigated. Of the 26 DCs performed in the past 3.5 years, 9 were ineffective because the expected BEs were absent on postoperative computed tomography. In those 9 cases, the Glasgow coma scale (GCS) scores and D-dimer of fibrinogen degradation product (FDP-DD) were significantly higher and lower, respectively, than those of the control group. Patients with EM showed similar trends regarding the GCS score and FDP-DD, both of which are probable indicators of BE. In patients without EM, the GCS score and FDP-DD were normal, but their base excess at admission was significantly low with increased ICP, requiring DC. GCS score and FDP-DD may represent the extent of mechanically damaged brain, and this may explain their relation with DC effectiveness in patients with EM. In patients without EM and with mild brain damage, base excess that reflects the respiratory or circulatory disorder should be the predictor for BE. (author)

  14. Summary of Prioritized Research Opportunities: Building America Program Planning Meeting, Washington, D.C., November 2-4, 2010

    Energy Technology Data Exchange (ETDEWEB)

    2011-02-01

    This report outlines the results of brainstorming sessions conducted at the Building America Fall 2010 planning meeting, in which research teams and national laboratories identified key research priorities to incorporate into multi-year planning, team research agendas, expert meetings, and technical standing committees.

  15. Research on design feasibility of high-power light-weight dc-to-dc converters for space power applications

    Science.gov (United States)

    Wilson, T. G.

    1981-01-01

    Utilizing knowledge gained from past experience with experimental current-or-voltage step-up dc-to-dc converter power stages operating at output powers up to and in excess of 2 kW, a new experimental current-or-voltage step-up power stage using paralleled bipolar junction transistors (BJTs) as the controlled power switch, was constructed during the current reporting period. The major motivation behind the construction of this new experimental power stage was to improve the circuit layout so as to reduce the effects of stray circuit parasitic inductances resulting from excess circuit lead lengths and circuit loops, and to take advantage of the layout improvements which could be made when some recently-available power components, particularly power diodes and polypropylene filter capacitors, were incorporated into the design.

  16. Shock Spectrum Calculation from Acceleration Time Histories

    Science.gov (United States)

    1980-09-01

    accurate and economical . If the velocity is desired, it can be calculated with Equation A-8b. As it stands it is exact. Approx- imation will be...Washington DC; DAEN-MCE.D (R L Wight) Washington DC; DAEN.MPE-D Washington DC; DAEN- MPU . Washington DC; DARCOM; ERADCOM Tech Supp Dir. (DELSD-L) Ft

  17. DEMETER Observations of ELF Waves Injected With the HAARP HF Transmitter

    Science.gov (United States)

    2006-08-17

    de Physique et Chimie de l’Environnement, Centre National de la Recherche Scientifique, Orléans, France. 3Naval Research Laboratory, Washington, D. C...stanford.edu) E. J. Kennedy, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375, USA. M. Parrot, Laboratoire de Physique et Chimie

  18. 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.

  19. Modeling and simulation for micro DC motor based on simulink

    Science.gov (United States)

    Shen, Hanxin; Lei, Qiao; Chen, Wenxiang

    2017-09-01

    The micro DC motor has a large market demand but there is a lack of theoretical research for it. Through detailed analysis of the commutation process of micro DC motor commutator, based on micro DC motor electromagnetic torque equation and mechanical torque equation, with the help of Simulink toolkit, a triangle connection micro DC motor simulation model is established. By using the model, a sample micro DC motor are simulated, and an experimental measurements has been carried on the sample micro DC motor. It is found that the simulation results are consistent with theoretical analysis and experimental results.

  20. Application research of power allocation based on Buck circuit in DC microgrid

    Directory of Open Access Journals (Sweden)

    Wang Zihao

    2017-01-01

    Full Text Available In a traditional DC microgrid, the power sharing control strategy has been always used in the distributed power converters, resulting in not making outer power allocation arbitrarily. In order to solve the power output allocation problem of wind power in DC microgrid, the intelligent Buck circuit based on PI algorithm and the load current feed-forward method was used to realize the arbitrary regulation of the output power of the wind power in the DC microgrid system. Compared with traditional distributed generators power-sharing method, the simulation and experimental results show the proposed method can realize arbitrary power outputting from distributed generators. Finally, the simulation and experimental results prove the validity and effectiveness of the control method.

  1. Shortcomings in Information Sharing Facilitates Transnational Organized Crime

    Science.gov (United States)

    2017-06-09

    Intelligence (Washington, DC: Government Printing Office, 2013). 7 Interagency: Of or pertaining to U.S. Government agencies and departments.20...Congress, The Intelligence Community in the 21st Century (Washington, DC: Government Printing Office, 1996), 6. 55 Geospatial- Intelligence Agency...Publication 2, Joint Intelligence . Washington, DC: Government Printing Office, 2013. Kundra, Vivek. Federal Cloud Computing Strategy. Washington, DC

  2. An Anthropologist Examines the Navy’s Recruiting Process.

    Science.gov (United States)

    1981-12-01

    who come to these border towns primarily to pur- chase appliances, electrical and electronic goods, automobile parts, some kinds of clothing, and some...Am automobile in order to entice him away from the Navy. There are some relatively stringent security requirements for Cuban appli- cants. The...22217 Naval Military Personnel Command HRm Department (NMPC-6)Naval Research Laboratory Washington, DC 20350 Code 2627Codenon 262 WahigtnDC205 Washington

  3. Analyzing Sanctuary Management in the Sahel

    Science.gov (United States)

    2015-06-12

    Afghanistan and Iraq, but they often lack the specific skills required for the multicultural , multilingual, and multinational environment of the Sahel...article/2013/11/14/us-africa-usa-military-idUSBRE9AD1AA20131114. Arieff, Alexis. 2013. Crisis in Mali. Washington, DC: U.S. Library of Congress...2011. US Special Operations Forces (SOF): Background and Issues for Congress. Washington, DC: U.S. Library of Congress, Congressional Research Service

  4. Reliability and Engineering of Thin-Film Photovoltaic Modules. Research forum proceedings

    Science.gov (United States)

    Ross, R. G., Jr. (Editor); Royal, E. L. (Editor)

    1985-01-01

    A Research Forum on Reliability and Engineering of Thin Film Photovoltaic Modules, under sponsorship of the Jet Propulsion Laboratory's Flat Plate Solar Array (FSA) Project and the U.S. Department of Energy, was held in Washington, D.C., on March 20, 1985. Reliability attribute investigations of amorphous silicon cells, submodules, and modules were the subjects addressed by most of the Forum presentations. Included among the reliability research investigations reported were: Arrhenius-modeled accelerated stress tests on a Si cells, electrochemical corrosion, light induced effects and their potential effects on stability and reliability measurement methods, laser scribing considerations, and determination of degradation rates and mechanisms from both laboratory and outdoor exposure tests.

  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. The performance of the DC motor by the PID controlling PWM DC-DC boost converter

    OpenAIRE

    Can, Erol; Sayan, Hasan Hüseyin

    2017-01-01

    This paper presents the PID controlling direct current (DC) to the direct current boost converter feds DC motor which has a 3.68 kW and 240 V of DC voltage input on its characteristics. What is first formed is the boost converter mathematical model at the design stage. Secondly, a mathematical model of the DC motor is created so that the boost converter with the machine can be established and modeled at the Matlab Simulink. The PID controller is considered for arranging a pulse width modulati...

  7. Research and Development in Support of the Navy Technology Center for Safety and Survivability

    Science.gov (United States)

    1990-10-26

    Automotive Engineers. Inc. * Warrendale. PA (1984). (6) Zeelenberg . A. P.. FIJa ven Drat. HI. 3.. end Barker. H1. L.. Coor. Interastona Dlan Machines A...given by Zeelenberg et al.3. The CCAI is based on two simple in Table 1. The fuels were ranked in order of their measurements, namely viscosity and...authors thank R. N. Hazlett (Naval Research 3 Zeelenberg , A. P., Fijn van Draat, H. J. and Barker. H. L. ’Congres Laboratory, Washington, DC) for helpful

  8. On and off controlled resonant dc-dc power converter

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a resonant DC-DC power converter comprising an input side circuit comprising a positive and a negative input terminal for receipt of an input voltage or current and an output side circuit comprising positive and negative output terminals for supply of a converter...... output voltage and connection to a converter load. The resonant DC-DC power converter further comprises a rectification circuit connected between an output of a resonant network and the output side circuit. The resonant network is configured for alternatingly being charged from the input voltage...... or current and discharged through the rectification circuit by a first controllable switch arrangement in accordance with a first switch control signal. A second controllable switch arrangement of the resonant DC-DC power converter is configured to select a first impedance characteristic of the resonant...

  9. Rehabilitation medicine summit: building research capacity Executive Summary

    Directory of Open Access Journals (Sweden)

    Kemp John D

    2006-01-01

    Full Text Available Abstract The general objective of the "Rehabilitation Medicine Summit: Building Research Capacity" was to advance and promote research in medical rehabilitation by making recommendations to expand research capacity. The five elements of research capacity that guided the discussions were: 1 researchers; 2 research culture, environment, and infrastructure; 3 funding; 4 partnerships; and 5 metrics. The 100 participants included representatives of professional organizations, consumer groups, academic departments, researchers, governmental funding agencies, and the private sector. The small group discussions and plenary sessions generated an array of problems, possible solutions, and recommended actions. A post-Summit, multi-organizational initiative is called to pursue the agendas outlined in this report (see Additional File 1. Additional File 1 A table outlining the Final Action Plan of the Rehabilitation Medicine Summit: Building Research Capacity held on April 28–29, 2005 in Washington, DC. Click here for file

  10. Artificial neural network control of sab dc/dc converter

    International Nuclear Information System (INIS)

    Mahar, M.A.; Abro, M.R.; Larik, A.S.

    2009-01-01

    The latest development of power semiconductor devices enable the modern power electronic converters to withstand high voltage and high power applications. Power electronic converters are mostly periodic variable structure systems due to their switched operations. The main drawback of these converters is the generation of oscillations which are developed during the operation of the converters under nonlinear situations. To handle these nonlinearities, various researchers have proposed different control techniques. Power electronic designers are devoting in the further development of converter topologies and their control techniques. SAB (Single Active Bridge) DC/DC converter is a new topology recently introduced by Demetriades. This topology is used in high voltage and high power applications. Because of its smart features, SAB converter has recently drawn attention of many researchers. However, during the operation of SAB converter severe oscillations are generated. In this research work, a novel NNC (Neural Network Controller) model is developed for SAB converter to minimize oscillations generated during its operation. NNC is believed to be an advanced nonlinear and robust controller which has the ability to map the nonlinear behaviour in a negligible response time. The performance of SAB converter with NNC is tested under dynamic region by considering the reference voltage variation and duty ratio variation. The SAB converter is implemented and simulated in MATLAB/Simulink. The simulated results are presented. (author)

  11. 75 FR 27401 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-30, DC-9-40, and DC-9-50...

    Science.gov (United States)

    2010-05-17

    ... Airworthiness Directives; McDonnell Douglas Corporation Model DC- 9-30, DC-9-40, and DC-9-50 Series Airplanes... airworthiness directive (AD) for certain Model DC-9-30, DC-9-40, and DC-9-50 series airplanes. This AD requires... this AD to detect and correct the potential for an arc/spark condition to occur within the fuel boost...

  12. Proceedings of the Military Operations Research Society Mini-Symposium on Analysis of Tactical Transportation: Progress and Challenges (TACTRAN) Held in Alexandria, Virginia on 16-17 February 1988

    Science.gov (United States)

    1989-10-31

    V ) oLC . WL LUU ( nElI .0 .&M z : OI C) ~ QO2. E7 a~I 0 Lndlu 2 0 g w w USiII s.. LL U , CC W jc C LIr c cc Q. o C3 * L _ (r MI >I~ LI a Fiue1...Washington, DC 20301 Washington, DC 20310 Office Phone: (202)-695-9212, A/V: 225-9212 Office Phone: MR Fred W Solarczyk MR Stanley L Spaulding McDonnell

  13. 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.

  14. 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 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....

  15. PHALANX, The Bulletin of Military Operations Research. Volume 43, Number 4, December 2010

    Science.gov (United States)

    2010-12-01

    it has even began. Military planners could use this information in designing war games and scenarios. Alternatively, preventative strategies could...Lyle staggered in on Monday morning after a deeply unsatisfying weekend. His alma mater had been crushed in a major televised football game on... Salon H Washington D.C. More Information to Come! MORS Quarterly Member Reception 7 December 2010 Walter E. Washington Convention Center 801 Mount

  16. Using PBL to Improve Educational Outcomes and Student Satisfaction in the Teaching of DC/DC and DC/AC Converters

    Science.gov (United States)

    Martinez-Rodrigo, Fernando; Herrero-De Lucas, Luis Carlos; de Pablo, Santiago; Rey-Boue, Alexis B.

    2017-01-01

    This paper examines the question of how to use project-based learning to increase student performance and satisfaction in a power electronics course addressing the topics of dc/dc and dc/ac converters, the assembly of a dc/dc converter, and the use of a commercial speed drive. A detailed presentation of the methodology is shown, and the results…

  17. Reliability of Capacitors for DC-Link Applications in Power Electronic Converters

    DEFF Research Database (Denmark)

    Wang, Huai; Blaabjerg, Frede

    2014-01-01

    DC-link capacitors are an important part in the majority of power electronic converters which contribute to cost, size and failure rate on a considerable scale. From capacitor users' viewpoint, this paper presents a review on the improvement of reliability of dc link in power electronic converters...... from two aspects: 1) reliability-oriented dc-link design solutions; 2) conditioning monitoring of dc-link capacitors during operation. Failure mechanisms, failure modes and lifetime models of capacitors suitable for the applications are also discussed as a basis to understand the physics......-of-failure. This review serves to provide a clear picture of the state-of-the-art research in this area and to identify the corresponding challenges and future research directions for capacitors and their dc-link applications....

  18. 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...

  19. 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

  20. 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)

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

    2015-01-01

    Background 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. Objective 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. Methods 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. Results 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. Conclusions 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

  1. 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.

  2. 78 FR 10636 - Task Force on Research on Violence Against American Indian and Alaska Native Women; Meeting

    Science.gov (United States)

    2013-02-14

    ... Justice Programs, U.S. Department of Justice, 810 7th Street NW., 3rd Floor Ballroom, Washington, DC 20531... the Director of the Office on Violence Against Women, established the Task Force on March 31, 2008. A... Violence Against Women, United States Department of Justice, 145 N Street NE., Suite 10W.121, Washington...

  3. 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.

  4. The Florida Prostate Cancer Research Training Opportunities for Outstanding Leaders (ReTOOL (registered trademark)) Program: Creating Opportunities for Minority HBCU Students

    Science.gov (United States)

    2013-03-01

    underserved. (MA Haynes & BD Smedley (Eds). National Academy Press, Washington DC. 2. Norris KC, Agodoa LY (2005). The need for health professionals... Robert Vessella, PhD University of Washington Medical Center 44 10:30 – 10:45 am S-10 A Targeted Approach to Prostate Radiotherapy Alan

  5. CALS Test Network Handbook

    Science.gov (United States)

    1993-03-01

    Ltd Gillette Company Dorset, England Boston MA Foreign Broadcast Information Set. Giordano Associates Inc Frederick MD Long Branch NJ Formtek Inc...Associates Orem UT College Park MD InfoDesign Corp Johns Hopkins University Toronto, Ontario Laurel MD Information Spectrum Inc Joint Committee on Printing...Inc Washington DC Bel Air MD Navy Naval Research Laboratory OutSource Inc Washington DC Los Angeles CA 22 i +’ . S.. . -- -,•w• -- w,,Wmwmm mm -- m mmm

  6. RESONANT STEP-DOWN DC-DC POWER CONVERTERS

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a resonant step-down 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...... 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......-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...

  7. Atmel Microcontroller Based Soft Switched PWM ZVS Full Bridge DC to DC Converter

    Directory of Open Access Journals (Sweden)

    DEEPAK KUMAR NAYAK

    2010-12-01

    Full Text Available This paper deals with the simulation and implementation of soft switched PWM ZVS full bridge DC to DC converter. The 48V DC is efficiently reduced to 12V DC using a DC to DC converter. This converter has advantages like reduced switching losses, stresses and EMI. Input DC is converted into high frequency AC and it is stepped down to 12V level. Later it is rectified using a full wave rectifier. Laboratory model of microcontroller based DC to DC converter is fabricated and tested. The experimental results are compared with the simulation results.

  8. Quasi-Z-Source Half-Bridge DC-DC Converter for Photovoltaic Applications

    OpenAIRE

    Vinnikov, D; Chub, A; Husev, O; Zaķis, J

    2015-01-01

    This paper presents a novel quasi-Z-source halfbridge galvanically isolated DC-DC converter intended for the photovoltaic applications. The topology could be envisioned as an alternative to the boost half-bridge DC-DC converter but the benefit of its symmetric structure reduces the threat of transformer saturation due to the dc flux. The proposed converter features the continuous input current and could be used either with one or two input voltage sources.

  9. 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.

  10. 78 FR 15053 - Simpson Lumber Company, LLC, Shelton, Washington; Simpson Lumber Company, LLC, Tacoma, Washington...

    Science.gov (United States)

    2013-03-08

    ...,372B] Simpson Lumber Company, LLC, Shelton, Washington; Simpson Lumber Company, LLC, Tacoma, Washington; Simpson Lumber Company, LLC, Longview, Washington; Notice of Revised Determination on Reconsideration On... Reconsideration for the workers and former workers of Simpson Lumber Company, LLC, Shelton, Washington (TA-W-81...

  11. Control of the DC-DC Converter used into Energy Generation System

    International Nuclear Information System (INIS)

    Bizon, Nicu; Oproescu, Mihai

    2006-01-01

    This paper presents an investigation of the DC-DC Converter controller used into Energy Generation System. The full bridge is used into an Energy Generation System (EGS) as second power interface between the energy source and the high DC bus. The simulation results show that the DC-DC Converter behavior can be improved using a well designed PI control surface. The used Simulink models for the EGS blocks and some design considerations are presented, too. (authors)

  12. Research on current sharing of paralleled IGBTs in different DC breaker circuit topologies

    Directory of Open Access Journals (Sweden)

    Chen Ying

    2016-01-01

    Full Text Available IGBT modules used in series and parallel to satisfy the requirement in high-power DC circuit breakers are often prone to large-current destruction due to current unbalance between paralleled IGBTs. It is of great importance to identify the current unbalance causes and to find a method optimizing the current sharing of paralleled IGBTs. In this paper the current-sharing influencing factors are discussed and verified by simulation. Two possible circuit topologies used in DC circuit breakers are proposed and simulated to see their performance in current sharing. The results show that one of them can provide us with a simple and effective method to achieve good current balancing in the DC circuit breaker application.

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

    Science.gov (United States)

    1978-10-01

    to the oral cavity , with its abundance and variety of streptococci, has recently been implicated as playing a larger role than previously appreciated...the dressings of oral wounds. Impending studies will more closely identify the microbiota involved and the importance to healing in the oral ...to the oral cavity as was seen in a similar study in which stainless steel wires were used to achieve fixation. 5) The staples apply continuous

  14. Distributed Control for Paralleled PWM Inverters in the DC Zonal Distribution System

    National Research Council Canada - National Science Library

    Marinac, Mark

    1999-01-01

    .... The advantages of DC ZEDS will be exploited in the next class of surface combatants. Part of the development research for DC ZEDS includes the design of autonomous DC-to-AC inverter modules having robust load sharing capability...

  15. Implementation method of multi-terminal DC control system

    Science.gov (United States)

    Yi, Liu; Hao-Ran, Huang; Jun-Wen, Zhou; Hong-Guang, Guo; Yu-Yong, Zhou

    2018-04-01

    Currently the multi-terminal DC system (MTDC) has more stations. Each station needs operators to monitor and control the device. It needs much more operation and maintenance, low efficiency and small reliability; for the most important reason, multi-terminal DC system has complex control mode. If one of the stations has some problem, the control of the whole system should have problems. According to research of the characteristics of multi-terminal DC (VSC-MTDC) systems, this paper presents a strong implementation of the multi-terminal DC Supervisory Control and Data Acquisition (SCADA) system. This system is intelligent, can be networking, integration and intelligent. A master control system is added in each station to communication with the other stations to send current and DC voltage value to pole control system for each station. Based on the practical application and information feedback in the China South Power Grid research center VSC-MTDC project, this system is higher efficiency and save the cost on the maintenance of convertor station to improve the intelligent level and comprehensive effect. And because of the master control system, a multi-terminal system hierarchy coordination control strategy is formed, this make the control and protection system more efficiency and reliability.

  16. NSA Diana Wueger Published in Washington Quarterly

    OpenAIRE

    Grant, Catherine L.

    2016-01-01

    National Security Affairs (NSA) News NSA Faculty Associate for Research Diana Wueger has recently had an article titled “India’s Nuclear-Armed Submarines: Deterrence or Danger?” published in the Washington Quarterly.

  17. Application of digital control techniques for satellite medium power DC-DC converters

    Science.gov (United States)

    Skup, Konrad R.; Grudzinski, Pawel; Nowosielski, Witold; Orleanski, Piotr; Wawrzaszek, Roman

    2010-09-01

    The objective of this paper is to present a work concerning a digital control loop system for satellite medium power DC-DC converters that is done in Space Research Centre. The whole control process of a described power converter bases on a high speed digital signal processing. The paper presents a development of a FPGA digital controller for voltage mode stabilization that was implemented using VHDL. The described controllers are a classical digital PID controller and a bang-bang controller. The used converter for testing is a simple model of 5-20 W, 200 kHz buck power converter. A high resolution digital PWM approach is presented. Additionally a simple and effective solution of filtering of an analog-to-digital converter output is presented.

  18. 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.

  19. Design of interleaved multilayer rosen type piezoelectric transformer for high voltage dc/dc applications

    DEFF Research Database (Denmark)

    Rødgaard, Martin Schøler; Andersen, Thomas; Meyer, Kaspar Sinding

    2012-01-01

    Research and development within piezoelectric transformer (PT) based converters are rapidly increasing as the technology is maturing and starts to prove its capabilities. Especially for high voltage and high step-up applications, PT based converters have demonstrated good performance and DC...

  20. Financial implications of the accident at Three Mile Island. Oversight hearings before the Committee on Interior and Insular Affairs, House of Representatives, Ninety-Seventh Congress, First Session on financial implications of the accident at Three Mile Island, hearings held in Washington, DC, May 4-5, 1981

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    Five panel presentations and a total of 21 witnesses testified at a two-day hearing May 4-5, 1981, in Washington, DC, on the financial consequences of the Three Mile Island (TMI) accident and the economic issues of the cleanup. The committee's goal was to listen to recommendations for government response and to determine the government's proper role and whether legislation is necessary to fulfill that role. Another issue under consideration was the restart of the undamaged unit one. The hearing record includes testimony of witnesses representing the nuclear power industry, environmental groups, and the financial and insurance industries and three appendices with additional materials

  1. 76 FR 21712 - Meeting of the Ocean Research and Resources Advisory Industry Sub-Panel

    Science.gov (United States)

    2011-04-18

    ... creative problem-solving to overcome impediments to industry progress toward deploying operational projects... held at the Consortium for Ocean Leadership, 1201 New York Avenue, NW., 4th Floor, Washington, DC 20005...

  2. 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

    2013-01-01

    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

  3. Novel composite resonance DC-DC converter with voltage doubler rectifier

    OpenAIRE

    Kato, Hisatsugu; Matsuo, Hirohumi; Eguchi, Masaki; Sakamoto, Yukitaka; Nakaishi, Masaki

    2009-01-01

    This paper deals with a novel composite resonance DC-DC converter with the voltage doubler rectifier, which is developed to be applied to the power conditioner of the photovoltaic generation system. The proposed DC-DC converter has the current and voltage resonance functions. Therefore, the output voltage regulation can be achieved for the large variations of the input voltage and load. Also, this converter has the high power efficiency. The maximum power efficiency 96.1% can be realized.

  4. Ultra-high Efficiency DC-DC Converter using GaN Devices

    DEFF Research Database (Denmark)

    Ramachandran, Rakesh

    2016-01-01

    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...... for many decades. However, the rate of improvement slowed as the silicon power materials asymptotically approached its theoretical bounds. Compared to Si, wideband gap materials such as Silicon Carbide (SiC) and Gallium Nitride (GaN) are promising semiconductors for power devices due to their superior...... in this thesis. Efficiency measurements from the hardware prototype of both the topologies are also presented in this thesis. Finally, the bidirectional operation of an optimized isolated dc-dc converter is presented. The optimized converter has achieved an ultra-high efficiency of 98.8% in both directions...

  5. Advances in Exposure Science (Washington, DC Modernized TSCA meeting)

    Science.gov (United States)

    I am describing current research from the Chemical Safety for Sustainability research program's Rapid Exposure and Dosimetry project that relates to predicting human exposure to environmental chemicals for thousands of chemicals.

  6. 23 science societies issue joint call for more federal research dollars

    Science.gov (United States)

    Carlowicz, Michael

    In an unprecedented demonstration of unity, the leaders of 23 American scientific societies and umbrella organizations gathered on March 4 in Washington, D.C., to press the U.S. federal government for increased funding for scientific research and to make an investment in the nation's future. In a “Joint Statement on Scientific Research” addressed to President Bill Clinton and the Congress, the presidents of learned societies representing more than one million scientists, mathematicians, and engineers asked the government “to renew the nation's historical commitment to scientific research and education,” and to reverse the decline of federal investment in science and engineering. The American Geophysical Union was one of the signatories of the statement.

  7. 75 FR 61352 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-30, DC-10-30F, DC-10-30F (KC...

    Science.gov (United States)

    2010-10-05

    ... Airworthiness Directives; McDonnell Douglas Corporation Model DC- 10-30, DC-10-30F, DC-10-30F (KC-10A and KDC-10...-13 McDonnell Douglas Corporation: Amendment 39-16448; Docket No. FAA-2010-0553; Directorate.... Applicability (c) This AD applies to McDonnell Douglas Corporation Model DC- 10-30, DC-10-30F, DC-10-30F (KC-10A...

  8. Sliding-Mode Control of a Charger/Discharger DC/DC Converter for DC-Bus Regulation in Renewable Power Systems

    Directory of Open Access Journals (Sweden)

    Sergio Ignacio Serna-Garcés

    2016-03-01

    Full Text Available Stand-alone power systems based on renewable energy sources are used to replace generators based on fossil fuels. Those renewable power systems also require Energy Storage Devices (ESD interfaced by a charger/discharger power converter, which consist of a bidirectional DC/DC converter, and a DC bus. This paper proposes a single sliding-mode controller (SMC for the charger/discharger DC/DC converter to provide a stable DC bus voltage in any operation condition: charging or discharging the ESD, or even without any power exchange between the ESD and the DC bus. Due to the non-linear nature of the power converter, the SMC parameters are adapted on-line to ensure global stability in any operation condition. Such stability of the adaptive SMC is mathematically demonstrated using analytical expressions for the transversality, reachability and equivalent control conditions. Moreover, a design procedure for the adaptive SMC parameters is provided in order to ensure the dynamic response required for the correct operation of the load. Finally, simulations and experimental tests validate the proposed controller and design procedure.

  9. Design and Analysis of Two-Phase Boost DC-DC Converter

    OpenAIRE

    Taufik Taufik; Tadeus Gunawan; Dale Dolan; Makbul Anwari

    2010-01-01

    Multiphasing of dc-dc converters has been known to give technical and economical benefits to low voltage high power buck regulator modules. A major advantage of multiphasing dc-dc converters is the improvement of input and output performances in the buck converter. From this aspect, a potential use would be in renewable energy where power quality plays an important factor. This paper presents the design of a 2-phase 200W boost converter for battery charging application. Analysis of results fr...

  10. 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.

  11. Virginia Tech launches Energy Efficiency Partnership with Hannon Armstrong and Pepco Energy Services aimed at greening greater Washington, D.C.

    OpenAIRE

    Micale, Barbara L.

    2007-01-01

    Virginia Tech announced Monday the "Energy Efficiency Partnership of Greater Washington," a landmark initiative to tackle the problem of global warming by retrofitting existing buildings with energy efficiency products designed to decrease energy use and significantly cut carbon emissions.

  12. A Review of Galvanically Isolated Impedance-Source DC–DC Converters

    DEFF Research Database (Denmark)

    Chub, Andrii; Vinnikov, Dmitri; Blaabjerg, Frede

    2016-01-01

    Impedance-source converters, an emerging technology in electric energy conversion, overcome limitations of conventional solutions by the use of specific impedance-source networks. Focus of this paper is on the topologies of galvanically isolated impedance-source dc-dc converters. These converters...... isolated dc-dc converters according to the element that transfers energy from the input to the output: a transformer, a coupled inductor, or their combination. This classification reveals advantages and disadvantages, as well as a wide space for further research. This paper also outlines the most promising...

  13. Basic Design Report of DC-TOF Inelastic Neutron Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    So, Ji Yong; Park, Je Geun; Moon, Myung Kook; Cho, Sang Jin; Choi, Yung Hyun; Lee, Chang Hee

    2006-04-15

    We made Basic designs of neutron guide, choppers, and detectors in order to optimize the design parameters of DC-TOF to be built in the HANARO Cold Neutron Guide Hall. In addition, we calculated the expected performance of DC-TOF using Monte Carlo simulations and evaluated the properties of neutron beam. Based on the results we obtained, we have compared the expected performance of the DC-TOF with those of existing instruments overseas. In conclusion, we believe that we will be able to construct the DC-TOF at HANARO as one of the best instruments of its kinds and it will become an invaluable instrument to researchers in the related field.

  14. 76 FR 59162 - Notice Pursuant to the National Cooperative Research and Production Act of 1993-National Center...

    Science.gov (United States)

    2011-09-23

    .... Specifically, Anglicotech LLC, Washington, DC; Battelle, Columbus, OH; Baxter Healthcare Corporation, Round...; ARC Technology Solutions, LLC, Nashua, NH; BAE Systems, Wayne, NJ; BCT Technology, Inc., Keene, NH...

  15. 75 FR 75872 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-30, DC-9-40, and DC-9-50...

    Science.gov (United States)

    2010-12-07

    ... Airworthiness Directives; McDonnell Douglas Corporation Model DC- 9-30, DC-9-40, and DC-9-50 Series Airplanes...: We are adopting a new airworthiness directive (AD) for the McDonnell Douglas Corporation airplanes... to include an airworthiness directive (AD) that would apply to certain McDonnell Douglas Model DC-9...

  16. 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...

  17. A Long-term View of Research Targets in Nanoelectronics

    International Nuclear Information System (INIS)

    Cavin, R. K.; Zhirnov, V. V.; Bourianoff, G. I.; Hutchby, J. A.; Herr, D. J. C.; Hosack, H. H.; Joyner, W. H.; Wooldridge, T. A.

    2005-01-01

    This paper presents a summary of the second workshop on Silicon Nanoelectronics and Beyond held at the National Science Foundation in Washington DC in December 2004. The objective was to set research directions to vigorously pursue both extending the CMOS technology to its limits and to develop Beyond-CMOS technologies to sustain the historical exponential improvement in performance/cost with time. Workshop themes were: (1) Post CMOS information processing technologies, (2) Novel materials and assembly methods for extending charge-based technology to its ultimate limits, (3) Multi-scale/multi-phenomena modeling and simulation, (4) Novel nano-architectures, and (5) Nano environmental safety and health

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

    Directory of Open Access Journals (Sweden)

    Carlos Andrés Ramos-Paja

    2014-05-01

    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.

  19. 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

  20. A Novel PPFHB Bidirectional DC-DC Converter for Supercapacitor Application

    DEFF Research Database (Denmark)

    Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael Andreas E.

    2009-01-01

    This paper presents a novel bidirectional DC-DC converter for the supercapacitor application. In the proposed converter, push-pull forward with half bridge (PPFHB) voltage doubler structure is used to reduce the number of the power switches and get higher voltage gain. Based on phase-shift modula......This paper presents a novel bidirectional DC-DC converter for the supercapacitor application. In the proposed converter, push-pull forward with half bridge (PPFHB) voltage doubler structure is used to reduce the number of the power switches and get higher voltage gain. Based on phase...

  1. 78 FR 2429 - Notice of Inventory Completion: The Museum of Anthropology at Washington State University...

    Science.gov (United States)

    2013-01-11

    ... construction. Archaeologists working for the Washington Archaeological Research Center at Washington State... Reservation. Historical, ethnographic, linguistic, and archaeological information links the site to the...

  2. 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); Sinha, Mohit [University of Minnesota; Dhople, Sairaj [University of Minnesota; Poon, Jason [University of California at Berkeley

    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.

  3. Wetlands Research Program. Corps of Engineers Wetlands Delineation Manual. Appendix C. Sections 1 and 2. Region 2 - Southeast.

    Science.gov (United States)

    1987-01-01

    22 7.V.: 14 -1b Jil -7 1 N.- .- WETLANDS RESEARCH PROGRAM TECHNICAL REPORT Y-87-1 CORPS OF ENGINEERS WETLANDS DELINEATION MANUAL APPENDIX C SECTIONS ...ARMYLA- US Army Corps of Engineers Washington, DC 20314-1000 B , , , -I *. 4 -w *" APPENDIX C SECTION 1 NATIONAL LIST OF PLANT SPECIES THAT OCCUR IN...Redtop FACW A. hiernalia (Walter) B.S.P. Winter bent FAC A. scabra Wilid. Rough bentgrass FAC A. st~nfyaL. Carpet bentgrass FACW Aletris aurea

  4. Assessment of an Average Controller for a DC/DC Converter via Either a PWM or a Sigma-Delta-Modulator

    Directory of Open Access Journals (Sweden)

    R. Silva-Ortigoza

    2014-01-01

    Full Text Available Sliding mode control is a discontinuous control technique that is, by its nature, appropriate for controlling variable structure systems, such as the switch regulated systems employed in power electronics. However, when designing control laws based on the average models of these systems a modulator is necessary for their experimental implementation. Among the most widely used modulators in power electronics are the pulse width modulation (PWM and, more recently, the sigma-delta-modulator (Σ-Δ-modulator. Based on the importance of achieving an appropriate implementation of average control laws and the relevance of the trajectory tracking task in DC/DC power converters, for the first time, this research presents the assessment of the experimental results obtained when one of these controllers is implemented through either a PWM or a Σ-Δ-modulator to perform such a task. A comparative assessment based on the integral square error (ISE index shows that, at frequencies with similar efficiency, the Σ-Δ-modulator provides a better tracking performance for the DC/DC Buck converter. In this paper, an average control based on differential flatness was used to perform the experiments. It is worth mentioning that a different trajectory tracking controller could have been selected for this research.

  5. 77 FR 12579 - Notification of a Public Meeting of the Chartered Science Advisory Board

    Science.gov (United States)

    2012-03-01

    ... budget for EPA research and a draft report on science integration at EPA; to plan for a joint meeting of...). ADDRESSES: The meeting will be held at The Washington Plaza Hotel, 10 Thomas Circle NW., Washington, DC. FOR... Requested FY 2013 Research Budget for EPA The chartered SAB will conduct a quality review of an SAB draft...

  6. OffshoreDC DC grids for integration of large scale wind power

    DEFF Research Database (Denmark)

    Zeni, Lorenzo; Endegnanew, Atsede Gualu; Stamatiou, Georgios

    The present report summarizes the main findings of the Nordic Energy Research project “DC grids for large scale integration of offshore wind power – OffshoreDC”. The project is been funded by Nordic Energy Research through the TFI programme and was active between 2011 and 2016. The overall...... objective of the project was to drive the development of the VSC based HVDC technology for future large scale offshore grids, supporting a standardised and commercial development of the technology, and improving the opportunities for the technology to support power system integration of large scale offshore...

  7. 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

  8. CISH is induced during DC development and regulates DC-mediated CTL activation.

    Science.gov (United States)

    Miah, Mohammad Alam; Yoon, Cheol-Hee; Kim, Joonoh; Jang, Jinah; Seong, Young-Rim; Bae, Yong-Soo

    2012-01-01

    The cytokine inducible SH2-domain protein (CISH) is a well-known STAT5 target gene, but its role in the immune system remains uncertain. In this study, we found that CISH is predominantly induced during dendritic cell (DC) development from mouse bone marrow (BM) cells and plays a crucial role in type 1 DC development and DC-mediated CTL activation. CISH knockdown reduced the expression of MHC class I, co-stimulatory molecules and pro-inflammatory cytokines in BMDCs. Meanwhile, the DC yield was markedly enhanced by CISH knockdown via cell-cycle activation and reduction of cell apoptosis. Down-regulation of cell proliferation at the later stage of DC development was found to be associated with CISH-mediated negative feedback regulation of STAT5 activation. In T-cell immunity, OT-1 T-cell proliferation was significantly reduced by CISH knockdown in DCs, whereas OT-2 T-cell proliferation was not affected by CISH knockdown. CTLs generated by DC vaccination were also markedly reduced by CISH knockdown, followed by significant impairment of DC-based tumor immunotherapy. Taken together, our data suggest that CISH expression at the later stage of DC development triggers the shutdown of DC progenitor cell proliferation and facilitates DC differentiation into a potent stimulator of CTLs. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Molecular Biology of Medulloblastoma

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2007-12-01

    Full Text Available Current methods of diagnosis and treatment of medulloblastoma, and the influence of new biological advances in the development of more effective and less toxic therapies are reviewed by researchers at Children’s National Medical Center, The George Washington University, Washington, DC.

  10. Research on power equalization using a low-loss DC-DC chopper for lithium-ion batteries in electric vehicle

    Science.gov (United States)

    Wei, Y. W.; Liu, G. T.; Xiong, S. N.; Cheng, J. Z.; Huang, Y. H.

    2017-01-01

    In the near future, electric vehicle is entirely possible to replace traditional cars due to its zero pollution, small power consumption and low noise. Lithium-ion battery, which owns lots of advantages such as lighter and larger capacity and longer life, has been widely equipped in different electric cars all over the world. One disadvantage of this energy storage device is state of charge (SOC) difference among these cells in each series branch. If equalization circuit is not allocated for series-connected batteries, its safety and lifetime are declined due to over-charge or over-discharge happened, unavoidably. In this paper, a novel modularized equalization circuit, based on DC-DC chopper, is proposed to supply zero loss in theory. The proposed circuit works as an equalizer when Lithium-ion battery pack is charging or discharging or standing idle. Theoretical analysis and control method have been finished, respectively. Simulation and small scale experiments are applied to verify its real effect.

  11. A Bidirectional Multi-Port DC-DC Converter Integrating Voltage Equalizer

    DEFF Research Database (Denmark)

    Chen, Jianfei; Hou, Shiying; Deng, Fujin

    2015-01-01

    A novel bidirectional multi-port dc-dc converter integrating voltage equalizer based on switched-capacitor voltage accumulator (SCVA) is proposed. It has two operating modes of charging and discharging for battery modules. All battery modules are connected in series indirectly and can be equalize...... battery modules with different voltages. Simulation results has shown the feasibility of the proposed converter.......A novel bidirectional multi-port dc-dc converter integrating voltage equalizer based on switched-capacitor voltage accumulator (SCVA) is proposed. It has two operating modes of charging and discharging for battery modules. All battery modules are connected in series indirectly and can be equalized...

  12. Funding health sciences research: a strategy to restore balance

    National Research Council Canada - National Science Library

    Bloom, Floyd E; Randolph, Mark A

    1990-01-01

    ... Funds Division of Health Sciences Policy Institute of Medicine Floyd E. Bloom and Mark A. Randolph, editors NATIONAL ACADEMY PRESS Washington, D.C. 1990 Copyrightoriginal retained, the be not from cannot book, paper original however, for version formatting, authoritative the typesetting-specific created from the as publication files other...

  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...

  14. 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.

  15. Douglas Lowy and Nirali Shah discuss advancements in cancer treatment at the second annual Chasing Cancer Summit | Center for Cancer Research

    Science.gov (United States)

    On Monday, September 18, 2017, the second annual Chasing Cancer Summit was held at the Washington Post headquarters in downtown Washington, D.C. The live event brought together a group of experts, including CCR’s Douglas Lowy, M.D., and Nirali Shah, M.D., for discussions on the latest developments in cancer detection and treatment.  Read more...

  16. 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.

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

    Science.gov (United States)

    Denzinger, Wolfgang; Hintze, Thomas

    2014-08-01

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

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

    Science.gov (United States)

    Schwab, J. R.

    1979-01-01

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

  19. Next-Generation Shipboard DC Power System

    DEFF Research Database (Denmark)

    Jin, Zheming; Sulligoi, Giorgio; Cuzner, Rob

    2016-01-01

    sources (RES) are commonly recognized as the major driven force of the revolution, the outburst of customer electronics and new kinds of household electronics is also powering this change. In this context, dc power distribution technologies have made a comeback and keep gaining a commendable increase...... in research interests and industrial applications. In addition, the concept of flexible and smart distribution has also been proposed, which tends to exploit distributed generation and pack the distributed RESs and local electrical loads as an independent and self-sustainable entity, namely microgrid....... At present, the research of dc microgrid has investigated and developed a series of advanced methods in control, management and objective-oriented optimization, which would found the technical interface enabling the future applications in multiple industrial areas, such as smart buildings, electric vehicles...

  20. Characterising and modelling extended conducted electromagnetic interference in densely packed DC-DC converter

    CSIR Research Space (South Africa)

    Grobler, Inus

    2013-09-01

    Full Text Available . The military specified DC-DC converters are applicable, spanning from 100 W handheld power managers up to 2 kW DC-DC battery chargers. Circuit layout high frequency effects as well as high frequency impedances of the power components were characterised...

  1. A New Sliding Mode Controller for DC/DC Converters in Photovoltaic Systems

    Directory of Open Access Journals (Sweden)

    M. Sarvi

    2013-01-01

    Full Text Available DC/DC converters are widely used in many industrial and electrical systems. As DC/DC converters are nonlinear and time-variant systems, the application of linear control techniques for the control of these converters is not suitable. In this paper, a new sliding mode controller is proposed as the indirect control method and compared to a simple direct control method in order to control a buck converter in photovoltaic applications. The solar arrays are dependent power sources with nonlinear voltage-current characteristics under different environmental conditions (insolation and temperature. From this point of view, the DC/DC converter is particularly suitable for the application of the sliding mode control in photovoltaic application, because of its controllable states. Simulations are performed in Matlab/Simulink software. The simulation results are presented for a step change in reference voltage and input voltage as well as step load variations. The simulations results of proposed method are compared with the conventional PID controller. The results show the good performance of the proposed sliding mode controller. The proposed method can be used for the other DC/DC converter.

  2. 75 FR 58413 - Center for Scientific Review; Notice of Closed Meetings

    Science.gov (United States)

    2010-09-24

    ... evaluate grant applications. Place: The Ritz-Carlton, Washington DC, 1150 22nd Street, NW., Washington, DC... p.m. to 5 p.m. Agenda: To review and evaluate grant applications. Place: The Ritz-Carlton...Continental Hotel, 1401 Pennsylvania Avenue, NW., Washington, DC 20004. Contact Person: Eugene Carstea, PhD...

  3. 76 FR 55737 - Proposed Privacy Act Systems of Records

    Science.gov (United States)

    2011-09-08

    ...., Washington, DC 20219-0001. (4) Bureau of Engraving and Printing (BEP): 14th & C Streets, SW. Washington, DC... Street, NW., Washington, DC 20239. (9) Financial Crimes Enforcement Network (FinCEN), Vienna, VA 22183... structured around need and is determined by the person's role in the organization. Printed materials are...

  4. 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...

  5. 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...

  6. The Impact of NSF-funded Physics Education Research at the University of Washington

    Science.gov (United States)

    Heron, Paula

    2015-03-01

    It is now well known that many students who complete introductory physics courses are unable to apply fundamental concepts in situations that involve qualitative reasoning. Systematic investigations have helped researchers understand why so many students fail to develop robust and coherent conceptual frameworks, and have led to the development of new teaching practices and materials that are far more effective than conventional ones. The Physics Education Group at the University of Washington has played a leading role in raising awareness of the need to improve instruction, and in supporting physics faculty in their efforts to do so. With support from the National Science Foundation, the group has helped build a research base that instructors can draw on, and has produced practical, flexible instructional materials that promote deeper learning in physics classrooms. Both ``Tutorials in Introductory Physics'' (Pearson, 2002) and ``Physics by Inquiry'' (Wiley, 1996) have been developed in an iterative process in which ongoing assessment of student learning plays an integral role. These materials have had a widespread and significant impact on physics teaching and on student learning from kindergarten through graduate school. In this talk I will describe the role of research in curriculum development, and speculate on the next generation of tools and resources to support physics teaching and learning.

  7. 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...

  8. A High-Voltage Low-Power Switched-Capacitor DC-DC Converter Based on GaN and SiC Devices for LED Drivers

    DEFF Research Database (Denmark)

    Fan, Lin; Knott, Arnold; Jørgensen, Ivan Harald Holger

    2018-01-01

    Previous research on switched-capacitor DC-DC converters has focused on low-voltage and/or high-power ranges where the efficiencies are dominated by conduction loss. Switched-capacitor DC-DC converters at high-voltage (> 100 V) low-power (high efficiency and high power density...... are anticipated to emerge. This paper presents a switched-capacitor converter with an input voltage up to 380 V (compatible with rectified European mains) and a maximum output power of 10 W. GaN switches and SiC diodes are analytically compared and actively combined to properly address the challenges at high......-voltage low-current levels, where switching loss becomes significant. Further trade-off between conduction loss and switching loss is experimentally optimized with switching frequencies. Three variant designs of the proposed converter are implemented, and the trade-off between the efficiency and the power...

  9. Regulation of DC development and DC-mediated T-cell immunity via CISH

    OpenAIRE

    Miah, Mohammad Alam; Bae, Yong-Soo

    2013-01-01

    Cytokine inducible SH2-containing protein (CISH) plays a crucial role in type 1 dendritic cell (DC) development as well as in the DC-mediated activation of cytotoxic T lymphocytes (CTLs). CISH expression at late DC developmental stages shuts down the proliferation of DC progenitors by negatively regulating signal transducer and activator of transcription 5 (STAT5) and facilitates the differentiation of DCs into potent stimulators of CTLs.

  10. Regulation of DC development and DC-mediated T-cell immunity via CISH.

    Science.gov (United States)

    Miah, Mohammad Alam; Bae, Yong-Soo

    2013-03-01

    Cytokine inducible SH2-containing protein (CISH) plays a crucial role in type 1 dendritic cell (DC) development as well as in the DC-mediated activation of cytotoxic T lymphocytes (CTLs). CISH expression at late DC developmental stages shuts down the proliferation of DC progenitors by negatively regulating signal transducer and activator of transcription 5 (STAT5) and facilitates the differentiation of DCs into potent stimulators of CTLs.

  11. 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 operations...

  12. Historical changes to Lake Washington and route of the Lake Washington Ship Canal, King County, Washington

    Science.gov (United States)

    Chrzastowski, Michael J.

    1983-01-01

    Lake Washington, in the midst of the greater Seattle metropolitan area of the Puget Sound region (fig. 1), is an exceptional commercial, recreational, and esthetic resource for the region . In the past 130 years, Lake Washington has been changed from a " wild " lake in a wilderness setting to a regulated lake surrounded by a growing metropolis--a transformation that provides an unusual opportunity to study changes to a lake's shoreline and hydrologic characteristics -resulting from urbanization.

  13. Electrical Tree Initiation and Growth in Silicone Rubber under Combined DC-Pulse Voltage

    Directory of Open Access Journals (Sweden)

    Tao Han

    2018-03-01

    Full Text Available Electrical tree is a serious threat to silicone rubber (SIR insulation and can even cause breakdown. Electrical trees under alternating current (AC and direct current (DC voltage have been widely researched. While there are pulses in high-voltage direct current (HVDC cables under operating conditions caused by lightning and operating overvoltage in the power system, little research has been reported about trees under combined DC-pulse voltage. Their inception and growth mechanism is still not clear. In this paper, electrical trees are studied under several types of combined DC-pulse voltage. The initiation and growth process was recorded by a digital microscope system. The experimental results indicate that the inception pulse voltage is different under each voltage type and is influenced by the combined DC. The initial tree has two structures, determined by the pulse polarity. With increased DC prestressing time, tree inception pulse voltage with the same polarity is clearly decreased. Moreover, a special initial bubble tree was observed after the prestressing DC.

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

    International Nuclear Information System (INIS)

    Li Hong; Zhang Bo; Li Zhong; Halang, Wolfgang A.; Chen Guanrong

    2009-01-01

    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.

  15. Research and Development Strategies for Human Centered and Group Support Technologies

    Science.gov (United States)

    1992-05-01

    13 Detma W. Straub, Jr. and Renee Beauclair , "A New Dimension to Decision Support: Organizational Planning Made Easy with GDSS," Data Management...and Exposition, Washington, DC, June 1991. Straub, Detmar W., Jr., and Renee Beauclair , "A New Dimension to Decision Support: Organizational Planning

  16. 76 FR 41825 - NASA Advisory Council; Meeting

    Science.gov (United States)

    2011-07-15

    ... Avenue, NASA Research Park, NASA Ames Research Center (ARC), Moffett Field, CA 94035-1000. FOR FURTHER... Headquarters, Washington, DC 20546, 202/358-1148. SUPPLEMENTARY INFORMATION: The agenda for the meeting will...

  17. Proceedings of the 1993 Particle Accelerator Conference Held in Washington, DC on May 17-20, 1993. Volume 5

    Science.gov (United States)

    1994-05-18

    stability. o)i-_ =o)- +I +aOc. Summarizing above relations, the net transfer of power per electron with kinetic energy W is written RI ado ;k of d method•. as... Porno . equations (3)XS) in cylindrical[V~ -lA!-]+ (Ip+2q)A coordinates for a general, Le. not necessarily azxiymanet-2a dC ric, beam. It is valid for

  18. 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.

  19. 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.

  20. Common mode noise in three-level DC-DC converters

    CSIR Research Space (South Africa)

    Grobler, Inus

    2009-09-01

    Full Text Available that three-level buck DC-DC converters in general generate much lower common mode currents than conventional two-level buck converters. Further, reductions in common mode currents are achieved by using the improved three-level topologies that have been...

  1. Marine Transportation System Performance Measures Research

    Science.gov (United States)

    2016-06-01

    the water resource project suitability can be evaluated according to National Economic Development (NED) principles (U.S. Army Corps of Engineers...www.census.gov/ econ /census/about/. U.S. Census Bureau, Foreign Trade Division. 2015. FT920 - U.S. Merchandise Trade: Selected Highlights (annual issues...Updated Principles , Requirements and Guidelines for Water and Land Related Resources Implementation Studies. Washington, DC: The White House. World

  2. Facilities for Study and Research in the Offices of the United States Government at Washington. Bulletin, 1909, No. 1. Whole Number 398

    Science.gov (United States)

    Hadley, Arthur Twining

    1909-01-01

    This bulletin contains a report prepared by President Hadley of Yale University on the facilities for advanced study and research in the offices of the National Government at Washington. Especial interest attaches to this publication. It sets forth, in compact form, information which has frequently been sought by institutions and individuals…

  3. Analysis and Design of Bi-Directional DC-DC Converter in the Extended Run Time DC UPS System Based on Fuel Cell and Supercapacitor

    DEFF Research Database (Denmark)

    Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.

    2009-01-01

    Abstract-In this paper, an extended run time DC UPS system structure with fuel cell and supercapacitor is investigated. A wide input range bi-directional dc-dc converter is described along with the phase-shift modulation scheme and phase-shift with duty cycle control, in different modes. The deli......Abstract-In this paper, an extended run time DC UPS system structure with fuel cell and supercapacitor is investigated. A wide input range bi-directional dc-dc converter is described along with the phase-shift modulation scheme and phase-shift with duty cycle control, in different modes...

  4. Journal of Genetics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Department of Biological Sciences, George Washington University, 333 Lisner Hall, 2023 G St. NW, Washington, DC 20052, USA; Institute for Neuroscience, George Washington University, 636 Ross Hall, 2300 I St. NW, Washington DC 20037, USA; Department of Biology, Genome Evolution Laboratory, National University ...

  5. 77 FR 47047 - Biomass Research and Development Technical Advisory Committee

    Science.gov (United States)

    2012-08-07

    ... Committee Act (Public Law No. 92-463, 86 Stat. 770) requires that agencies publish these notices in the.... ADDRESSES: Renaissance DuPont Hotel, 1143 New Hampshire Avenue, NW., Washington, DC 20037. FOR FURTHER...: In keeping with procedures, members of the public are welcome to observe the business of the Biomass...

  6. Development of toroid-type HTS DC reactor series for HVDC system

    Science.gov (United States)

    Kim, Kwangmin; Go, Byeong-Soo; Park, Hea-chul; Kim, Sung-kyu; Kim, Seokho; Lee, Sangjin; Oh, Yunsang; Park, Minwon; Yu, In-Keun

    2015-11-01

    This paper describes design specifications and performance of a toroid-type high-temperature superconducting (HTS) DC reactor. The first phase operation targets of the HTS DC reactor were 400 mH and 400 A. The authors have developed a real HTS DC reactor system during the last three years. The HTS DC reactor was designed using 2G GdBCO HTS wires. The HTS coils of the toroid-type DC reactor magnet were made in the form of a D-shape. The electromagnetic performance of the toroid-type HTS DC reactor magnet was analyzed using the finite element method program. A conduction cooling method was adopted for reactor magnet cooling. The total system has been successfully developed and tested in connection with LCC type HVDC system. Now, the authors are studying a 400 mH, kA class toroid-type HTS DC reactor for the next phase research. The 1500 A class DC reactor system was designed using layered 13 mm GdBCO 2G HTS wire. The expected operating temperature is under 30 K. These fundamental data obtained through both works will usefully be applied to design a real toroid-type HTS DC reactor for grid application.

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

    Science.gov (United States)

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

    2016-10-01

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

  8. Y-Source Boost DC/DC Converter for Distributed Generation

    DEFF Research Database (Denmark)

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

    2015-01-01

    This paper introduces a versatile Y-source boost dc/dc converter intended for distributed power generation, where high gain is often demanded. The proposed converter uses a Y-source impedance network realized with a tightly coupled three-winding inductor for high voltage boosting that is presently...

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

    Energy Technology Data Exchange (ETDEWEB)

    Marlino, Laura D [ORNL; Zhu, Lizhi [Ballard Power Systems/Siemens VDO

    2007-07-01

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

  10. Multi-level cascaded DC/DC converters for PV applications

    Directory of Open Access Journals (Sweden)

    Ahmed A.A. Hafez

    2015-12-01

    Full Text Available A robust multi-level cascaded DC/DC system for Photovoltaic (PV application is advised in this article. There are three PV generators, each is coupled to a half-bridge buck cell. Each PV-generator–buck-converter channel is controlled such that maximum power is captured independently under different irradiation and temperature levels. The system operation under normal and abnormal conditions was comprehensively investigated. Internal Model Control (IMC technique was adopted for tuning the controllers. An elaborate switching modulation strategy was used to reduce the current ripple and inductor size, while maintaining high efficiency. Annotative, simple and robust remedial strategies were proposed to mitigate different anticipated faults. Comprehensive simulation results in Matlab environment were illustrated for corroborating the performance of the advised cascaded DC/DC system under normal/abnormal conditions. The proposed system enjoys the merits of independency, reduced volumetric dimensions and improved efficiency. Furthermore, the system is inherently fault-tolerant.

  11. Job Satisfaction among Information Technology Professionals in the Washington DC Area: An Analysis Based on the Minnesota Satisfaction Questionnaire

    Science.gov (United States)

    Diala, Ify S.

    2010-01-01

    Information technology (IT) has in the recent times dominated all aspect of the business world, and, for this reason, today's business environment is more challenging and more dynamic than in previous years. Therefore, this study focused on examining job satisfaction of Information Technology professionals in the D.C. area, paying particular…

  12. 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.

  13. Development of DC-TOF control software framework

    International Nuclear Information System (INIS)

    Kim, Hong Joo; Kim, Hyun Ok

    2010-06-01

    Disk-Chopper Time-of-Flight spectrometer (DC-TOF) is a new cold neutron instrument under construction at the Korea Atomic Energy Research Institute (KAERI). It will be equipped with a total of 352 2m PSDs(Position Sensitive Detectors), which are grouped into 11 panels. We developed the main DAQ/Control software works well between multi-DSPs of electronics and user. It is convenient to operate DC-TOF system and monitor it's data quality using GUI(Graphical User Interface). Also it satisfies design throughout with test result of 100K events/s

  14. Auxiliary resonant DC tank converter

    Science.gov (United States)

    Peng, Fang Z.

    2000-01-01

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

  15. 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.

  16. Efficiency Analyses of a DC Residential Power Distribution System for the Modern Home

    Directory of Open Access Journals (Sweden)

    GELANI, H. E.

    2015-02-01

    Full Text Available The electric power system started as DC back in the nineteenth century. However, the DC paradigm was soon ousted by AC due to inability of DC to change its voltage level. Now, after many years, with the development of power electronic converters capable of stepping-up and down DC voltage and converting it to-and-from AC, DC appears to be challenging AC and attempting a comeback. We now have DC power generation by solar cells, fuel cells and wind farms, DC power transmission in the form of HVDC (High Voltage DC transmission, DC power utilization by various modern electronic loads and DC power distribution that maybe regarded as still in research phase. This paper is an attempt to investigate feasibility of DC in the distribution portion of electrical power system. Specifically, the efficiency of a DC distribution system for residential localities is determined while keeping in view the concept of daily load variation. The aim is to bring out a more practical value of system efficiency as the efficiencies of DC/DC converters making up the system vary with load variation. This paper presents the modeling and simulation of a DC distribution system and efficiency results for various scenarios are presented.

  17. Better Jobs, Brighter Futures, a Stronger Washington. Washington's Community and Technical Colleges

    Science.gov (United States)

    Washington State Board for Community and Technical Colleges, 2015

    2015-01-01

    The world is changing rapidly. With changes in technology, demographics, and workforce trends, Washington needs colleges to not only keep pace, but lead the way. Washington's 34 community and technical colleges answer that call. The community and technical colleges have proven uniquely positioned to adapt to, embrace, and ignite change. Community…

  18. 78 FR 66027 - Center for Scientific Review; Amended Notice of Meeting

    Science.gov (United States)

    2013-11-04

    ... will be held at the Ritz-Carlton Hotel, 1150 22nd Street NW., Washington, DC 20037. The meeting will..., 2013, 11:00 a.m., Washington Hilton, 1919 Connecticut Avenue, Washington, DC 20009, which was published...

  19. Development of a green mode DC/DC converter available to portable nuclear instrument

    International Nuclear Information System (INIS)

    Gao Feiyan; Wu Longxiong; Tan Wei; Tang Yaogeng

    2010-01-01

    A green mode DC/DC converter was developed which suitable to the portable nuclear instrument which is powered by battery and is sometime at stand-by mode. Some updated control approaches such as pseudo-resonant type power supply control and synchronous rectification were adopted to makethe DC/DC converter operate with low power consumption and high efficiency. The test results the battery can be prolonged with this converter. (authors)

  20. Performance power evaluation of DC fan cooling system for PV panel by using ANSYS CFX

    Science.gov (United States)

    Syafiqah, Z.; Amin, N. A. M.; Irwan, Y. M.; Irwanto, M.; Leow, W. Z.; Amelia, A. R.

    2017-09-01

    A research has been conducted to find the optimum combination for DC fan air cooling system of photovoltaic (PV) panel. During normal operation of PV panel, it is estimated that only 15 % of solar radiation is converted into electrical energy. Meanwhile, the rest of the solar radiation is converted into heat energy which affects the performance of the PV panel. Therefore, the aim of this research is to investigate the performance power evaluation of DC fan cooling system for PV panel by using ANSYS CFX. The effect of airflow configuration of DC fan has been investigated. This is to analyze whether the airflow circulation of DC fan cause a change towards the maximum temperature of PV panel. Besides, the impact of varying number of DC fans attached at the back of PV panel is evaluated. The result of airflow circulation of DC fan has been discussed. Meanwhile, with the increment number of DC fans, the PV panel temperature drops significantly. As a conclusion, the optimum number of DC fans is two with the combination of inlet airflow.

  1. Oil spill response issues in Washington State

    International Nuclear Information System (INIS)

    Lempriere, P.R.

    1997-01-01

    Washington State statutes and regulations applicable to oil transport and oil spills were described. Specific provisions of the statutes and regulations and other relevant matters were also discussed. Among these were: (1) Washington State oil spill prevention plans, (2) Washington State oil spill contingency plans, (3) best achievable protection, (4) Intertanko's lawsuit against Washington State, (5) oil spill removal organizations, (6) certificates of financial responsibility in Washington State, (7) extent of potential liability under Washington Law, (8) disposal of cleanup materials, and (9) definition of 'qualified individuals' on marine vessels having the authority to implement removal actions

  2. 78 FR 7791 - Center for Scientific Review; Notice of Closed Meetings

    Science.gov (United States)

    2013-02-04

    ...; Notice of Closed Meetings Pursuant to section 10(d) of the Federal Advisory Committee Act, as amended (5...: Doubletree Hotel Washington, 1515 Rhode Island Avenue NW., Washington, DC 20005. Contact Person: Joanne T.... Place: Washington Plaza Hotel, 10 Thomas Circle NW., Washington, DC 20005. Contact Person: Jin Huang, Ph...

  3. A Dual-Buck–Boost AC/DC Converter for DC Nanogrid With Three Terminal Outputs

    DEFF Research Database (Denmark)

    Wu, Weimin; Wang, Houqing; Liu, Yuan

    2017-01-01

    Due to the widely used dc characterized loads and more distributed power generation sources, the dc nanogrid becomes more and more popular, and it is seen as an alternative to the ac grid. For safety considerations, the dc nanogrid should provide reliable grounding for the residential loads...... such as the low-voltage ac power system. There are three typical grounding configurations for a dc nanogrid: the united grounding, the unidirectional grounding, and the virtual isolated grounding. Each grounding configuration has its own specifications to ac/dc converters. In this paper, a dual-buck-boost ac/dc...... converter for use in the united-grounding-configuration-based dc nanogrid with three terminal outputs is proposed. The working principle of this converter is presented in detail through analyzing the equivalent circuits. Experiments are carried out to verify the theoretical analysis....

  4. Wideband impedance measurements and modeling of DC motors for EMI predictions

    NARCIS (Netherlands)

    Diouf, F.; Leferink, Frank Bernardus Johannes; Duval, Fabrice; Bensetti, Mohamed

    2015-01-01

    In electromagnetic interference prediction, dc motors are usually modeled as a source and a series impedance. Previous researches only include the impedance of the armature, while neglecting the effect of the motor's rotation. This paper aims at measuring and modeling the wideband impedance of a dc

  5. DESIGN OPTIMIZATION OF RESONANT DC-DC CONVERTERS

    OpenAIRE

    Belqasem Aljafari

    2016-01-01

    Resonant DC/DC converters are the class of converters, which have L-C resonant tank serving as a major part of the power conversion process. The fundamental concept of the resonant converter is that the circulating energy in an L-C resonant circuit is manageable by changing the operating frequency, and therefore the converter can condition the input power to the desired output voltage. The development in power conversion technology is steady demand for high power efficiency and high power den...

  6. High Voltage Coil Current Sensor for DC-DC Converters Employing DDCC

    Directory of Open Access Journals (Sweden)

    M. Drinovsky

    2015-12-01

    Full Text Available Current sensor is an integral part of every switching converter. It is used for over-current protection, regulation and in case of multiphase converters for balancing. A new high voltage current sensor for coil-based current sensing in DC-DC converters is presented. The sensor employs DDCC with high voltage input stage and gain trimming. The circuit has been simulated and implemented in 0.35 um BCD technology as part of a multiphase DC-DC converter where its function has been verified. The circuit is able to sustain common mode voltage on the input up to 40 V, it occupies 0.387*0.345 mm2 and consumes 3.2 mW typically.

  7. Evaluating ballot initiative support for legalised marijuana: The case of Washington.

    Science.gov (United States)

    Collingwood, Loren; O'Brien, Ben Gonzalez; Dreier, Sarah

    2018-03-11

    In 2012, Washington and Colorado became the first U.S. states to legalise recreational marijuana. By 2016, eight states and the District of Columbia had legalised recreational marijuana, with more expected to consider it in 2018. Despite this trend, little academic research explains what drives ballot-initiative vote choice on marijuana legalisation. This paper uses a pre-election random sample voter survey to examine the individual characteristics that correlated with Washington voters' support for legal recreational marijuana. We find that voting on marijuana ballot initiatives largely reflects public opinion about marijuana and is particularly shaped voters' political ideology, party affiliation, religious affiliation and practice, and education. Notably, we find that those reporting experiences (i.e., someone they know) with the criminal justice system are more supportive of legalisation than those who do not. We conclude that marijuana legalisation voting behavior generally aligns with public opinion on the issue. However, one key aspect of Washington's legalisation campaign-the criminal injustices of marijuana illegality-helped shape Washington state voting behavior. Further research is needed to examine if, when, and in what contexts criminal justice campaign themes are likely to strengthen or undermine future states' marijuana legalisation efforts. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. On the modelling of linear-assisted DC-DC voltage regulators for photovoltaic solar energy systems

    Science.gov (United States)

    Martínez-García, Herminio; García-Vílchez, Encarna

    2017-11-01

    This paper shows the modelling of linear-assisted or hybrid (linear & switching) DC/DC voltage regulators. In this kind of regulators, an auxiliary linear regulator is used, which objective is to cancel the ripple at the output voltage and provide fast responses for load variations. On the other hand, a switching DC/DC converter, connected in parallel with the linear regulator, allows to supply almost the whole output current demanded by the load. The objective of this topology is to take advantage of the suitable regulation characteristics that series linear voltage regulators have, but almost achieving the high efficiency that switching DC/DC converters provide. Linear-assisted DC/DC regulators are feedback systems with potential instability. Therefore, their modelling is mandatory in order to obtain design guidelines and assure stability of the implemented power supply system.

  9. 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.

  10. HySafe research priorities workshop report Summary of the workshop organized in cooperation with US DOE and supported by EC JRC in Washington DC November 10-11 2014.

    Energy Technology Data Exchange (ETDEWEB)

    Jay Keller; Laura Hill; Kristian Kiuru; Groth, Katrina M.; Hecht, Ethan; Will James

    2016-03-01

    The HySafe research priorities workshop is held on the even years between the International Conference on Hydrogen Safety (ICHS) which is held on the odd years. The research priorities workshop is intended to identify the state-of-the-art in understanding of the physical behavior of hydrogen and hydrogen systems with a focus on safety. Typical issues addressed include behavior of unintended hydrogen releases, transient combustion phenomena, effectiveness of mitigation measures, and hydrogen effects in materials. In the workshop critical knowledge gaps are identified. Areas of research and coordinated actions for the near and medium term are derived and prioritized from these knowledge gaps. The stimulated research helps pave the way for the rapid and safe deployment of hydrogen technologies on a global scale. To support the idea of delivering globally accepted research priorities for hydrogen safety the workshop is organized as an internationally open meeting. In attendance are stakeholders from the academic community (universities, national laboratories), funding agencies, and industry. The industry participation is critically important to ensure that the research priorities align with the current needs of the industry responsible for the deployment of hydrogen technologies. This report presents the results of the HySafe Research Priorities Workshop held in Washing- ton, D.C. on November 10-11, 2014. At the workshop the participants presented updates (since the previous workshop organized two years before in Berlin, Germany) of their research and development work on hydrogen safety. Following the workshop, participants were asked to provide feedback on high-priority topics for each of the research areas discussed and to rank research area categories and individual research topics within these categories. The research areas were ranked as follows (with the percentage of the vote in parenthesis): 1. Quantitative Risk Assessment (QRA) Tools (23%) 2. Reduced Model

  11. 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.

  12. A Bidirectional Resonant DC-DC Converter Suitable for Wide Voltage Gain Range

    DEFF Research Database (Denmark)

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

    2018-01-01

    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...... losses. The operation principles and characteristics of the proposed converter are firstly analyzed in this paper. Then the analytical solutions for the voltage gain, soft-switching, and rms currents are derived, which facilitates the parameters design and optimization. Finally, the proposed topology...... and analysis are verified with experimental results obtained from a 1-kW converter prototype....

  13. Three-Phase Multistage System (DC-AC-DC-AC for Connecting Solar Cells to the Grid

    Directory of Open Access Journals (Sweden)

    Mahmudreza Changizian

    2017-11-01

    Full Text Available Inverter systems that feed electrical power from photovoltaic (PV system into the grid must convert the direct current of the PV array into the alternating current of the grid. In many applications, it is important for a converter to be lightweight, highly reliable, input/output isolated, flexible and operable in a boost mode. These features can be achieved by using a High-Frequency inverter which involves an isolated DC-DC stage and DC-AC section, which provides AC output. This paper proposes a new three phase topology, based on multi stage converter and PV system in order to use in medium and high power applications. The Perturb and Observe (P&O method is used for maximum power point tracking (MPPT control of PV array. The switching control signals for three-phase inverter are provided by hysteresis control method. Also, the comparison between the proposed topology and traditional structures has been conducted and finally the simulation researches are performed in a closed-loop control system by MATLAB/Simulink software to verify the operation of the proposed structure. The results represent better performance of the introduced system over traditional topologies.

  14. Y-source impedance-network-based isolated boost DC/DC converter

    DEFF Research Database (Denmark)

    Siwakoti, Yam P.; Town, Graham; Loh, Poh Chiang

    2014-01-01

    A dc-dc converter with very high voltage gain is proposed in this paper for any medium-power application requiring a high voltage boost with galvanic isolation. The proposed converter topology can be realized using only two switches. With this topology a very high voltage boost can be achieved even...... with a relatively low duty cycle of the switches, and the gain obtainable is presently not matched by any existing impedance network based converter operated at the same duty ratio. The proposed converter has a Y-source impedance network to boost the voltage at the intermediate dc-link side and a push......-pull transformer for square-wave AC inversion and isolation. The voltage-doubler rectifier provides a constant dc voltage at the output stage. A theoretical analysis of the converter is presented, supported by simulation and experimental results. A 250 W down-scaled prototype was implemented in the laboratory...

  15. Multilevel DC link inverter

    Science.gov (United States)

    Su, Gui-Jia

    2003-06-10

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

  16. Stability analysis of a high-step-Up DC grid-connected two-stage boost DC-DC converter

    Directory of Open Access Journals (Sweden)

    El Aroudi A.

    2014-01-01

    Full Text Available High conversion ratio switching converters are used whenever there is a need to step-up dc source voltage level to a much higher output dc voltage level such as in photovoltaic systems, telecommunications and in some medical applications. A simple solution for achieving this high conversion ratio is by cascading different stages of dc-dc boost converters. The individual converters in such a cascaded system are usually designed separately applying classical design criteria. However these criteria may not be applicable for the complete cascaded system . This paper first presents a glimpse on the bifurcation behavior that a cascade connection of two boost converters can exhibit. It is shown that the desired periodic orbit can undergo period doubling leading to subharmonic oscillations and chaotic regimes. Then, in order to simplify the analysis the second stage is considered as constant current sink and design-oriented analysis is carried out to obtain stability boundaries in the parameter space by taking into account slope interactions between the state variables in the two-different stages.

  17. 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.

  18. 75 FR 26952 - National Institute on Disability and Rehabilitation Research (NIDRR)-Disability and...

    Science.gov (United States)

    2010-05-13

    ... (National Health Interview Survey); and 3. U.S. Department of Labor, Bureau of Labor Statistics (Current.... Stapleton, D., O'Day, B., Livermore, G., and Imparato, A. (2006). Dismantling the Poverty Trap: Disability... force statistics from the current population survey. Washington, DC: Bureau of Labor Statistics. U.S...

  19. Digitally intensive DC-DC converter for extreme space environments, Phase II

    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...

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

    Energy Technology Data Exchange (ETDEWEB)

    Backhaus, Scott N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Swift, Gregory William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chatzivasileiadis, Spyridon [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Tschudi, William [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Glover, Steven [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Starke, Michael [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wang, Jianhui [Argonne National Lab. (ANL), Argonne, IL (United States); Yue, Meng [Brookhaven National Lab. (BNL), Upton, NY (United States); Hammerstrom, Donald [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-03-23

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

  1. Zero-voltage DC/DC converter with asymmetric pulse-width modulation for DC micro-grid system

    Science.gov (United States)

    Lin, Bor-Ren

    2018-04-01

    This paper presents a zero-voltage switching DC/DC converter for DC micro-grid system applications. The proposed circuit includes three half-bridge circuit cells connected in primary-series and secondary-parallel in order to lessen the voltage rating of power switches and current rating of rectifier diodes. Thus, low voltage stress of power MOSFETs can be adopted for high-voltage input applications with high switching frequency operation. In order to achieve low switching losses and high circuit efficiency, asymmetric pulse-width modulation is used to turn on power switches at zero voltage. Flying capacitors are used between each circuit cell to automatically balance input split voltages. Therefore, the voltage stress of each power switch is limited at Vin/3. Finally, a prototype is constructed and experiments are provided to demonstrate the circuit performance.

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

    DEFF Research Database (Denmark)

    Shen, Yanfeng; Wang, Huai; Blaabjerg, Frede

    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....

  3. Development of toroid-type HTS DC reactor series for HVDC system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kwangmin, E-mail: kwangmin81@gmail.com [Changwon National University, 55306 Sarim-dong, Changwon 641-773 (Korea, Republic of); Go, Byeong-Soo; Park, Hea-chul; Kim, Sung-kyu; Kim, Seokho [Changwon National University, 55306 Sarim-dong, Changwon 641-773 (Korea, Republic of); Lee, Sangjin [Uiduk University, Gyeongju 780-713 (Korea, Republic of); Oh, Yunsang [Vector Fields Korea Inc., Pohang 790-834 (Korea, Republic of); Park, Minwon; Yu, In-Keun [Changwon National University, 55306 Sarim-dong, Changwon 641-773 (Korea, Republic of)

    2015-11-15

    Highlights: • The authors developed the 400 mH, 400 A class toroid-type HTS DC reactor system. • The target temperature, inductance and operating current are under 20 K at magnet, 400 mH and 400 A, respectively. All target performances of the HTS DC reactor were achieved. • The HTS DC reactor was conducted through the interconnection operation with a LCC type HVDC system. • Now, the authors are studying the 400 mH, 1500 A class toroid-type HTS DC reactor for the next phase HTS DC reactor. - Abstract: This paper describes design specifications and performance of a toroid-type high-temperature superconducting (HTS) DC reactor. The first phase operation targets of the HTS DC reactor were 400 mH and 400 A. The authors have developed a real HTS DC reactor system during the last three years. The HTS DC reactor was designed using 2G GdBCO HTS wires. The HTS coils of the toroid-type DC reactor magnet were made in the form of a D-shape. The electromagnetic performance of the toroid-type HTS DC reactor magnet was analyzed using the finite element method program. A conduction cooling method was adopted for reactor magnet cooling. The total system has been successfully developed and tested in connection with LCC type HVDC system. Now, the authors are studying a 400 mH, kA class toroid-type HTS DC reactor for the next phase research. The 1500 A class DC reactor system was designed using layered 13 mm GdBCO 2G HTS wire. The expected operating temperature is under 30 K. These fundamental data obtained through both works will usefully be applied to design a real toroid-type HTS DC reactor for grid application.

  4. Development of toroid-type HTS DC reactor series for HVDC system

    International Nuclear Information System (INIS)

    Kim, Kwangmin; Go, Byeong-Soo; Park, Hea-chul; Kim, Sung-kyu; Kim, Seokho; Lee, Sangjin; Oh, Yunsang; Park, Minwon; Yu, In-Keun

    2015-01-01

    Highlights: • The authors developed the 400 mH, 400 A class toroid-type HTS DC reactor system. • The target temperature, inductance and operating current are under 20 K at magnet, 400 mH and 400 A, respectively. All target performances of the HTS DC reactor were achieved. • The HTS DC reactor was conducted through the interconnection operation with a LCC type HVDC system. • Now, the authors are studying the 400 mH, 1500 A class toroid-type HTS DC reactor for the next phase HTS DC reactor. - Abstract: This paper describes design specifications and performance of a toroid-type high-temperature superconducting (HTS) DC reactor. The first phase operation targets of the HTS DC reactor were 400 mH and 400 A. The authors have developed a real HTS DC reactor system during the last three years. The HTS DC reactor was designed using 2G GdBCO HTS wires. The HTS coils of the toroid-type DC reactor magnet were made in the form of a D-shape. The electromagnetic performance of the toroid-type HTS DC reactor magnet was analyzed using the finite element method program. A conduction cooling method was adopted for reactor magnet cooling. The total system has been successfully developed and tested in connection with LCC type HVDC system. Now, the authors are studying a 400 mH, kA class toroid-type HTS DC reactor for the next phase research. The 1500 A class DC reactor system was designed using layered 13 mm GdBCO 2G HTS wire. The expected operating temperature is under 30 K. These fundamental data obtained through both works will usefully be applied to design a real toroid-type HTS DC reactor for grid application.

  5. 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,

  6. Research on Control System of Three - phase Brushless DC Motor for Electric Vehicle

    Science.gov (United States)

    Wang, Zhiwei; Jin, Hai; Guo, Jie; Su, Jie; Wang, Miao

    2017-12-01

    In order to study the three-phase brushless motor control system of electric vehicle, Freescale9S12XS128 chip is used as the control core, and the power MOSFET is used as the inverter device. The software is compiled by Codewarrior software. The speed control link adopts open-loop control, and the control chip collects the external sensor signal voltage Change control PWM signal output control three-phase brushless DC motor speed. The whole system consists of Hall position detection module, current detection module, power drive module and voltage detection module. The basic functions of three-phase brushless DC motor drive control are realized.

  7. Digitally intensive DC-DC converter for extreme space environments, Phase I

    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...

  8. 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

    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....

  9. The United States Antarctic Program Data Center (USAP-DC): Recent Developments

    Science.gov (United States)

    Nitsche, F. O.; Bauer, R.; Arko, R. A.; Shane, N.; Carbotte, S. M.; Scambos, T.

    2017-12-01

    Antarctic earth and environmental science data are highly valuable, often unique research assets. They are acquired with substantial and expensive logistical effort, frequently in areas that will not be re-visited for many years. The data acquired in support of Antarctic research span a wide range of disciplines. Historically, data management for the US Antarctic Program (USAP) has made use of existing disciplinary data centers, and the international Antarctic Master Directory (AMD) has served as a central metadata catalog linking to data files hosted in these external repositories. However, disciplinary repositories do not exist for all USAP-generated data types and often it is unclear what repositories are appropriate, leading to many datasets being served locally from scientist's websites or not available at all. The USAP Data Center (USAP-DC; www.usap-dc.org), operated as part of the Interdisciplinary Earth Data Alliance (IEDA), contributes to the broader preservation of research data acquired with funding from NSF's Office of Polar Programs by providing a repository for diverse data from the Antarctic region. USAP-DC hosts data that spans the range of Antarctic research from snow radar to volcano observatory imagery to penguin counts to meteorological model outputs. Data services include data documentation, long-term preservation, and web publication, as well as scientist support for registration of data descriptions into the AMD in fulfillment of US obligations under the International Antarctic Treaty. In Spring 2016, USAP-DC and the NSIDC began a new collaboration to consolidate data services for Antarctic investigators and to integrate the NSF-funded glaciology collection at NSIDC with the collection hosted by USAP-DC. Investigator submissions for NSF's Glaciology program now make use of USAP-DC's web submission tools, providing a uniform interface for Antarctic investigators. The tools have been redesigned to collect a broader range of metadata. Each data

  10. 75 FR 60123 - Notice of Agreements Filed

    Science.gov (United States)

    2010-09-29

    .... Coleman, Esq.; Hoppel, Mayer & Coleman; 1000 Connecticut Avenue, NW.; Washington, DC 20036. [[Page 60124...: Paul D. Coleman, Esq.; Hoppel, Mayer & Coleman; 1050 Connecticut Avenue, NW.; Tenth Floor; Washington....; Hoppel, Mayer & Coleman; 1000 Connecticut Avenue, NW.; Washington, DC 20036. Synopsis: The amendment...

  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. Proceedings of public hearings: plutonium and the other transuranium elements, Washington, D.C., December 10--11, 1974. Volume 1

    International Nuclear Information System (INIS)

    1974-01-01

    The Environmental Protection Agency embarked on a program to evaluate the environmental impact of the transuranium elements and to consider whether further guidelines or standards are needed to assure adequate protection of the general ambient environment and of the public health from potential contamination of the environment by radionuclides of these elements. Public hearings were held in Washington, D. C., and Denver, Colorado, to gather information regarding the public and social implications of plutonium utilization; the factors involved in the balancing of costs vs benefits; dosimetry, health, and environmental effects; environmental levels and pathways; applications using plutonium; and control and cleanup technology. The proceedings of the hearing in Washington, D. C., Dec. 10-11, 1974, are presented. Data are included on current and potential sources of transuranium elements in the environment; animal studies on the tissue distribution of 233 U, 237 Np, 238 Pu, 239 Pu, 241 Am, 244 Cm, 249 Bk, 252 Cf, and 253 Es and pathological effects of body burdens of these radionuclides; and data on the health status of personnel known to have body burdens of 238 Pu or 239 Pu acquired during acute or chronic exposure, many of them over 30 years previously. It is pointed out that the lack of demonstrable biological effects of Pu in man provides presumptive evidence that the radiation protection standards in effect are adequate. (U.S.)

  13. Computer Simulation of Phase Shifted Series Resonant DC to DC Converter

    Directory of Open Access Journals (Sweden)

    P. PARVATHY

    2016-01-01

    Full Text Available This paper deals with digital simulation of phase shifted series resonant DC to DC converter using Matlab Simulink. The Simulink models for open loop and closed loop systems are developed and they are used for simulation studies. This converter is capable of producing ripple free DC output. Switching losses and switching stresses are reduced by using soft switching. This converter has advantages like high power density and low switching losses. Theoretical predictions are well supported by the simulation results.

  14. 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 ca...

  15. Planning and the Interagency Process: How can the United States Department of Defense and the Department of State Prepare for Future Joint Operations in a Time of Reduced Budgets?

    Science.gov (United States)

    2012-04-30

    Gabriel Marcella , ed., Affairs of State: The interagency and National Security (Washington, D.C., Strategic Studies Institute, 2008), 26. 6 James...8 Gabriel Marcella , 27. 9 Headquarters U.S. Marine Corps, Marine Corps Planning Process, MCWP 5-1 (Washington, D.C.: U.S. Marine Corps, August...17, 2012). Marcella , Gabriel, ed., Affairs of State: The Interagency and National Security (Washington, D.C., Strategic Studies Institute, 2008

  16. Corps G-2 Staff Competencies: A Desert Storm Case Study

    Science.gov (United States)

    2017-06-09

    Department of the Army, Army Doctrine Reference Publication (ADRP) 2-0, Intelligence (Washington, DC: Government Printing Office, August 2012), 3-2...Washington, DC: Government Printing Office, August 2012), 5-9. Intelligence Operations The second key corps G-2 intelligence meta-competency...Publication (ADRP) 2-0, Intelligence (Washington, DC: Government Printing Office, 2016), 4-2 to 4-9. Intelligence Analysis The final corps G-2

  17. Evolving Military Intelligence: The Effect of the Military Intelligence Service (MIS) and the Military Intelligence Organization (MIO) During the Korean and Vietnam Wars

    Science.gov (United States)

    2017-06-09

    Doctrine Publication (ADP) 2-0, Intelligence (Washington, DC: Government Printing Office, 2012), 1. 2 Scott D. Berrier, “ILE Branch Day” (Lecture, Command...Combat Intelligence (Washington, DC: Government Printing Office, 1951), 11-15. 6 groups of MI specialist teams within a larger tactical unit; allowing...Department of the Army, TOE 30- 115T, Combat Electronic Warfare Intelligence Battalion, Division (Washington, DC: Government Printing Office, 1976

  18. Mapping the brain and its functions: integrating enabling technologies into neuroscience research

    National Research Council Canada - National Science Library

    Pechura, Constance M; Martin, Joseph B

    1991-01-01

    ... and Joseph B. Martin, Editors Committee on a National Neural Circuitry Database Division of Health Sciences Policy Division of Biobehavioral Sciences and Mental Disorders Institute of Medicine National Academy Press Washington, D.C.1991 i Copyrightthe cannot be not from book, paper however, version for formatting, original authoritative the typ...

  19. Vision and change in biology undergraduate education: Vision and change from the funding front.

    Science.gov (United States)

    Holm, Bethany; Carter, Virginia Celeste; Woodin, Terry

    2011-01-01

    The purpose of this short article is to (a) briefly summarize the findings of two important recent resources concerning the future of biology in the 21(st) century; one, Vision and Change, A Call to Action [AAAS, 2009. AAAS, Washington, DC], concerned with undergraduate education in biology, the other, A New Biology for the 21st Century [National Research Council, 2009. National Academies Press, Washington, DC], concerned with advances within the discipline itself; (b) urge you, the reader of BAMBED, to review the material on the Vision and Change website [AAAS, 2009. AAAS: Washington, DC] and then to think how you might change things at your own institution and within your courses, and; (c) make readers aware of the programs at the National Science Foundation (NSF) that might support change efforts, as well as refer you to efforts other funding agencies are making to help biology undergraduate education respond to the challenges and opportunities chronicled in these two reports. Although NSF funding opportunities are specifically available to US investigators, the recommendations of the two reports should be of interest to a wide spectrum of international researchers. Copyright © 2011 Wiley Periodicals, Inc.

  20. Digital peak current mode control with adaptive slope compensation for DC-DC converters

    DEFF Research Database (Denmark)

    Andersen, Karsten Holm; Nymand, Morten

    2017-01-01

    performance and stability of current mode control. The presented method adapt to DC-DC converter operating conditions by estimating the rising and falling inductor current slopes, to apply a current slope compensation value to obtain a constant quality factor. The experimental results verifies the theoretical......This paper presents an adaptive slope compensation method for peak current mode control of digital controlled DC-DC converters, which controls the quality factor of the complex conjugated poles at half the switching frequency. Using quality factor control enables optimization of the dynamic...

  1. DC-Link Compensation Method for Slim DC Link Drives Fed by Soft Grid

    DEFF Research Database (Denmark)

    Mathe, Laszlo; Rosendahl Andersen, Henrik; Lazar, Radu

    2010-01-01

    Slim DC-link PWM (AC) drives for lowperformance applications are emerging on the market. Such drives equipped with a small DC-link capacitance exhibit instability tendencies, if installed on a soft line, giving a degraded performance. The total harmonic distortion (THD) and the partially weighted...... harmonic distortion (PWHD) of the line current are degraded, if resonance between the line impedance and the DC-link capacitance occurs. Likewise, the motor performance is affected negatively giving extra torque ripple, vibration and acoustic-noise emission. This paper proposes a novel DC-link compensation...

  2. High-power three-port three-phase bidirectional DC-DC converter

    NARCIS (Netherlands)

    Tao, H.; Duarte, J.L.; Hendrix, M.A.M.

    2007-01-01

    This paper proposes a three-port three-phase bidirectional dc-dc converter suitable for high-power applications. The converter combines a slow primary source and a fast storage to power a common load (e.g., an inverter). Since this type of system is gaining popularity in sustainable energy

  3. Precharge strategies for isolated modular DC-DC converters under two different start-up conditions

    DEFF Research Database (Denmark)

    Zhang, Yi; Wang, Huai; Li, Binbin

    2017-01-01

    The isolated modular DC-DC converter (IMDCC) is a new topology designed to connect high-voltage direct current (HVDC) lines with different voltage levels, which ties two DC grids by using two modular multilevel converters (MMCs) via a medium-frequency transformer. Due to the large value of capaci......The isolated modular DC-DC converter (IMDCC) is a new topology designed to connect high-voltage direct current (HVDC) lines with different voltage levels, which ties two DC grids by using two modular multilevel converters (MMCs) via a medium-frequency transformer. Due to the large value...... of capacitance in the IMDCC, proper precharge strategies before the start-up are significant for the safety and reliability of the whole system. This paper presents two closed-loop precharge control strategies to fully charge the sub-module (SM) capacitors of the IMDCC, considering two different start...

  4. 75 FR 34201 - Meeting Notice-Federal Interagency Committee on Emergency Medical Services

    Science.gov (United States)

    2010-06-16

    ... House Conference Center, 726 Jackson Place, Washington, DC. FOR FURTHER INFORMATION CONTACT: Drew Dawson... 11, 2010. Jeffrey P. Michael, Associate Administrator for Research and Program Development. [FR Doc...

  5. Research & Implementation of AC - DC Converter with High Power Factor & High Efficiency

    Directory of Open Access Journals (Sweden)

    Hsiou-Hsian Nien

    2014-05-01

    Full Text Available In this paper, we design and develop a high power factor, high efficiency two-stage AC - DC power converter. This paper proposes a two-stage AC - DC power converter. The first stage is boost active power factor correction circuit. The latter stage is near constant frequency LLC resonant converter. In addition to traditional LLC high efficiency advantages, light-load conversion efficiency of this power converter can be improved. And it possesses high power factor and near constant frequency operating characteristics, can significantly reduce the electromagnetic interference. This paper first discusses the main structure and control manner of power factor correction circuit. And then by the LLC resonant converter equivalent model proceed to circuit analysis to determine the important parameters of the converter circuit elements. Then design a variable frequency resonant tank. The resonant frequency can change automatically on the basis of the load to reach near constant frequency operation and a purpose of high efficiency. Finally, actually design and produce an AC – DC power converter with output of 190W to verify the characteristics and feasibility of this converter. The experimental results show that in a very light load (9.5 W the efficiency is as high as 81%, the highest efficiency of 88% (90 W. Full load efficiency is 87%. At 19 W ~ 190 W power changes, the operating frequency change is only 0.4 kHz (AC 110 V and 0.3 kHz (AC 220 V.

  6. 5 CFR Appendix C to Subpart B of... - Appropriated Fund Wage and Survey Areas

    Science.gov (United States)

    2010-01-01

    ... of Columbia, Washington, DC Survey Area District of Columbia: Washington, DC Maryland: Charles... Illinois: Cook Du Page Kane Lake McHenry Will Area of Application. Survey area plus: Illinois: Boone De...: Harrison Jennings Scott Washington Louisiana Lake Charles-Alexandria Survey Area Louisiana: Allen...

  7. Modeling and analysis of fractional order DC-DC converter.

    Science.gov (United States)

    Radwan, Ahmed G; Emira, Ahmed A; AbdelAty, Amr M; Azar, Ahmad Taher

    2017-07-11

    Due to the non-idealities of commercial inductors, the demand for a better model that accurately describe their dynamic response is elevated. So, the fractional order models of Buck, Boost and Buck-Boost DC-DC converters are presented in this paper. The detailed analysis is made for the two most common modes of converter operation: Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM). Closed form time domain expressions are derived for inductor currents, voltage gain, average current, conduction time and power efficiency where the effect of the fractional order inductor is found to be strongly present. For example, the peak inductor current at steady state increases with decreasing the inductor order. Advanced Design Systems (ADS) circuit simulations are used to verify the derived formulas, where the fractional order inductor is simulated using Valsa Constant Phase Element (CPE) approximation and Generalized Impedance Converter (GIC). Different simulation results are introduced with good matching to the theoretical formulas for the three DC-DC converter topologies under different fractional orders. A comprehensive comparison with the recently published literature is presented to show the advantages and disadvantages of each approach. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  8. Quenching of Emission and of Photochemistry for Aqueous Rh(NH3)5Cl(2+).

    Science.gov (United States)

    1979-04-01

    Hueneme, CalifornIa 93041 Attn: Dr. R. 3. Marcus 1 Attn: Mr. W. S. Haynes ONR Branch Offi ce Professor 0. Hein7 760 Market Street , Rm. 447...Peebles 1 WashI ngton, D.C. 20380 Directo r, Naval Research Laboratory Offi ce of Naval Researc hWashington, D.C. 20390 Arlington, VIrginia 22217

  9. 76 FR 4338 - Research and Development Strategies for Compressed & Cryo-Compressed Hydrogen Storage Workshops

    Science.gov (United States)

    2011-01-25

    ... Hydrogen Storage Workshops AGENCY: Fuel Cell Technologies Program, Office of Energy Efficiency and... the National Renewable Energy Laboratory, in conjunction with the Hydrogen Storage team of the EERE... hydrogen storage in the Washington, DC metro area. DATES: The workshops will be held on Monday, February 14...

  10. Magnetically coupled high-gain Y-source isolated DC/DC converter

    DEFF Research Database (Denmark)

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

    2014-01-01

    A new form of magnetically coupled DC/DC converter is proposed for medium power applications (250 W to 2 kW), requiring a high-voltage gain, short inductive charging time and galvanic isolation. The proposed converter can be realised using a unique Y-source impedance network and a two-switch push...

  11. The life test of a DC circuit breaker of tokamak device JT-60 for a nuclear fusion research

    International Nuclear Information System (INIS)

    Shimada, Ryuichi; Tani, Keiji; Kishimoto, Hiroshi; Tamura, Sanae; Yanabu, Satoru.

    1979-01-01

    In the Tokamak devices for nuclear fusion research, the construction of the current transformer circuits having plasma as the secondary circuit and the change of the primary circuit current are necessary for generating current in the plasma. This is considered to be fairly difficult in practice if conventional methods using capacitor discharge and iron core coils are employed. Considering such circumstances, it was decided for JT-60 to use an air-core current transformer coil and to employ the method of storing energy in the form of current in the coil inductance instead of a capacitor. For this reason, a DC circuit breaker is required to interrupt coil current. The authors improved an AV vacuum breaker, which had been developed as the vacuum breaker of longitudinal magnetic field type applying a magnetic field in parallel with an arc, to get the one for DC circuit for the purpose of applying it to JT-60. In this paper, the operational characteristic of the DC breaker is described, the construction and function of the life test circuit is explained, and the test results are reported. Finally, interruptions of 10,000 times at 20 kA were carried out. It is successful that the restrike of arc occurring during tens of milli-seconds after interruptions was improved to 0.05% or less for 10,000 times operations. Further, it was found that the generation of arc restrike can be reduced practically to zero with two breakers in series. (Wakatsuki, Y.)

  12. 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.

  13. Radiated electromagnetic emissions of DC-DC converters

    International Nuclear Information System (INIS)

    Feld, L; Jussen, R; Karpinski, W; Klein, K; Sammet, J; Wlochal, M

    2010-01-01

    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.

  14. Modeling, Analysis and Control of Different DC-DC Converter Topologies for Photo Voltaic Emulator

    Directory of Open Access Journals (Sweden)

    Mohammad Tauquir Iqbal

    2016-05-01

    Full Text Available This paper presents the modeling, analysis and control of different DC-DC converter topologies to emulate the photovoltaic (PV system. A PV emulator is basically a DC-DC converter having same electrical characteristics that of solar PV panel.  The emulator helps to achieve real characteristics of PV system in a better way in an environment where using actual PV systems can produce inconsistent results due to variation in weather conditions. The paper describes different types of DC-DC converters like buck, Resonant and Quasi Resonant Converter. The complete system is modelled in MATLAB® Simulink SimPowerSystem software package. The Simulation results obtained from the MATLAB® Simulink SimPowerSystem software package for different topologies under steady and dynamic conditions are analyzed and presented. An evaluation table is also presented at the end of the paper, presenting the effectiveness of each topology.

  15. As the Child Reads: The Treatment of Minorities in Textbooks and Other Teaching Materials. Conference Report, National NEA-PR&R Conference on Civil and Human Rights in Education (Washington, D. C., February 8-10, 1967).

    Science.gov (United States)

    Hart, Elinor, Ed.

    The conference on "The Treatment of Minorities in Textbooks and Other Teaching Materials" was held on February 8-10, 1967 in Washington, D.C. It was sponsored by the National Education Association and the Committee on Civil and Human Rights of Educators of the Commission on Professional Rights and Responsibilities. Attending the conference were…

  16. Sol-Gel Processing Science Using a Sol-Gel Optics Research Facility (SGORF)

    Science.gov (United States)

    1989-09-10

    Malaysia , Hong-Kong) where labor rates are perhaps one-tenth those of the U.S.. Figure 1 presents the trends of imports and exports of all optical... ACerS Annual Meeting, Washington, DC, May 1972. 2. W. A. Plummer, "Differential Dilatometry--A Powerful Tool," Corning Gla 33 Works, Corning, NY 14830

  17. Caloric Intake from Fast Food among Adults: United States, 2007-2010

    Science.gov (United States)

    ... Human Services, Assistant Secretary for Planning and Evaluation. Poverty guidelines, research, and measurement . Washington, DC. 2011. National Center for Health Statistics. National Health and Nutrition Examination Survey: Questionnaires, datasets, ...

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

    Science.gov (United States)

    Crapo, Alan D.; Lloyd, Jerry D.

    1991-03-01

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

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

    Science.gov (United States)

    1989-10-01

    PRICE, SLIM COCOMO, JS-3, SPQR -20, Softcost-R, etc) Cost questionnaire/ interview process Cost i methodology ueslionnaire/inlerview proc«»s...investigate the applicability of several cost models for trusted code cost and schedule estimation. The models examined were: SPQR /20...unsuccessful in calibrating either SPQR /20 or Softcost-R to a trusted code development environment. SPQR /20’s Internal calibration feature

  20. Fuel management at Washington State Ferries

    International Nuclear Information System (INIS)

    Brodeur, P.; Olds, J.

    2008-01-01

    This presentation discussed Washington State Ferry (WSF) operations and provided details of a biodiesel research and demonstration project. Washington has the largest ferry system in the United States, with a total of 28 vessels that operate on 10 routes through 20 terminals. Routes vary by transit times, navigational challenges, and the proximity to population centres. WSF fuel and emissions management initiatives include exhaust emission studies, clean fuel initiatives, machinery upgrades, fuel conservation initiatives, and biodiesel testing. The organization is also using waste heat recovery and a positive restraint system. The WSF biodiesel pilot program was conducted using soy-derived fuels with a purifier disk stack. The program is in agreement with recent legislation requiring that 2 per cent of annual diesel fuel sales are from biodiesel fuels, and state legislation requiring that state agencies use a minimum of 20 per cent biodiesel blends in diesel-powered vessels and vehicles. Details of project partnerships were included. tabs., figs

  1. Differential Mode EMI Filter Design for Isolated DC-DC Boost Converter

    DEFF Research Database (Denmark)

    Makda, Ishtiyaq Ahmed; Nymand, Morten

    2014-01-01

    A Differential Mode EMI filter for a low input voltage high-current isolated dc-dc boost converter is designed and presented in this paper. The primary side Differential Mode noise voltage is low due to the high transformer turn ratio, however, the input current is very high and since the EMI limit...... also does not change for such converters, it requires greatly optimized design approach for the filter including the correct sizing of the filter components. A complete analytical filter design process is carried out such a way that the Differential Mode noise voltage source in the converter...... is identified first. The DM noise model is then established and based on the harmonic analysis of the noise source voltage waveform, the complete Differential Mode EMI filter, including the filter resonance damping branch, is designed for a 3kW isolated dc-dc boost converter. The noise model and its theoretical...

  2. Current Mode Control for LLC Series Resonant DC-to-DC Converters

    Directory of Open Access Journals (Sweden)

    Jinhaeng Jang

    2015-06-01

    Full Text Available Conventional voltage mode control only offers limited performance for LLC series resonant DC-to-DC converters experiencing wide variations in operational conditions. When the existing voltage mode control is employed, the closed-loop performance of the converter is directly affected by unavoidable changes in power stage dynamics. Thus, a specific control design optimized at one particular operating point could become unacceptable when the operational condition is varied. This paper presents a new current mode control scheme which could consistently provide good closed-loop performance for LLC resonant converters for the entire operational range. The proposed control scheme employs an additional feedback from the current of the resonant tank network to overcome the limitation of the existing voltage mode control. The superiority of the proposed current mode control over the conventional voltage mode control is verified using an experimental 150 W LLC series resonant DC-to-DC converter.

  3. 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.

    1980-04-01

    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.

  4. 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.

  5. Hybrid electric system based on fuel cell and battery and integrating a single dc/dc converter for a tramway

    International Nuclear Information System (INIS)

    Fernandez, Luis M.; Garcia, Pablo; Garcia, Carlos Andres; Jurado, Francisco

    2011-01-01

    Research highlights: → Hybrid electric power system for a real surface tramway. → Hybrid system based on PEM fuel cell with dc/dc converter and Ni-MH battery. → New control strategy for the energy management of the tramway. → Hybrid system demonstrated to meet appropriate driving cycle of the tramway. -- Abstract: This paper presents a hybrid electric power system for a real surface tramway. The hybrid system consists of two electrical energy sources integrating a single dc/dc converter to provide the power demanded by the tramway loads (four electric traction motors and auxiliary services): (1) a Polymer Electrolyte Membrane (PEM) fuel cell (FC) as the primary and (2) a rechargeable Ni-MH battery as electrical energy storage to supplement the FC over the driving cycle. According to the requirements of the real driving cycle of the tramway, it was considered a 200 kW PEM FC system with two FCs connected in parallel and a 34 Ah Ni-MH battery. The PEM FC and Ni-MH battery models were designed from commercially available components. The power conditioning system provides the appropriate power for the tramway. It is composed of: (1) a unique dc/dc boot converter which adapts the FC output voltage to the 750 V traction standard dc bus; (2) three phase inverters to drive properly each electric motors; and (3) a braking chopper to dissipate excess of regenerative braking energy. Suitable state machine control architecture is presented for the hybrid system, its objective being to provide demanded power by the driving cycle, optimizing the energy generated. Following this objective, a new state machine control strategy based on eight states decides the operating point of each component of the system and a cascade control structure allows achieving the operating points determined by the strategy. Simulation results of the real driving cycle of the tramway check the adequacy of the hybrid electric power system.

  6. Hybrid electric system based on fuel cell and battery and integrating a single dc/dc converter for a tramway

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Luis M., E-mail: luis.fernandez@uca.e [Department of Electrical Engineering, EPS Algeciras, University of Cadiz, Avda. Ramon Puyol, s/n. 11202 Algeciras (Cadiz) (Spain); Garcia, Pablo, E-mail: pablo.garcia@uca.e [Department of Electrical Engineering, EPS Algeciras, University of Cadiz, Avda. Ramon Puyol, s/n. 11202 Algeciras (Cadiz) (Spain); Garcia, Carlos Andres, E-mail: carlosandres.garcia@uca.e [Department of Electrical Engineering, EPS Algeciras, University of Cadiz, Avda. Ramon Puyol, s/n. 11202 Algeciras (Cadiz) (Spain); Jurado, Francisco, E-mail: fjurado@ujaen.e [Department of Electrical Engineering, EPS Linares, University of Jaen, C/Alfonso X, No. 28. 23700 Linares (Jaen) (Spain)

    2011-05-15

    Research highlights: {yields} Hybrid electric power system for a real surface tramway. {yields} Hybrid system based on PEM fuel cell with dc/dc converter and Ni-MH battery. {yields} New control strategy for the energy management of the tramway. {yields} Hybrid system demonstrated to meet appropriate driving cycle of the tramway. -- Abstract: This paper presents a hybrid electric power system for a real surface tramway. The hybrid system consists of two electrical energy sources integrating a single dc/dc converter to provide the power demanded by the tramway loads (four electric traction motors and auxiliary services): (1) a Polymer Electrolyte Membrane (PEM) fuel cell (FC) as the primary and (2) a rechargeable Ni-MH battery as electrical energy storage to supplement the FC over the driving cycle. According to the requirements of the real driving cycle of the tramway, it was considered a 200 kW PEM FC system with two FCs connected in parallel and a 34 Ah Ni-MH battery. The PEM FC and Ni-MH battery models were designed from commercially available components. The power conditioning system provides the appropriate power for the tramway. It is composed of: (1) a unique dc/dc boot converter which adapts the FC output voltage to the 750 V traction standard dc bus; (2) three phase inverters to drive properly each electric motors; and (3) a braking chopper to dissipate excess of regenerative braking energy. Suitable state machine control architecture is presented for the hybrid system, its objective being to provide demanded power by the driving cycle, optimizing the energy generated. Following this objective, a new state machine control strategy based on eight states decides the operating point of each component of the system and a cascade control structure allows achieving the operating points determined by the strategy. Simulation results of the real driving cycle of the tramway check the adequacy of the hybrid electric power system.

  7. Design of PI Controlled Non Isolated Bidirectional DC to DC Converter for Electric Vehicle Application

    Science.gov (United States)

    Geetha, A.; Subramani, C.; Thamizh Thentral, T. M.; Krithika, V.; Usha, S.

    2018-04-01

    Non isolated Bidirectional DC-DC Converter (NIBDDC) is a good interface between DC source and inverter Fed induction motor drive. This paper deals with comparison between open loop and PI controlled Bidirectional DC to DC Converter Inverter System (BDDCIS). The modelling and control of BDDC is becomes an important issue. Open loop BDDCIS and closed loop PI controlled BDDCIS are designed, modelled and simulated using Matlab- simulink and their results are presented. The investigations indicate superior performance of PI controlled BDDCIS. The proposed BDDCIS has advantages like bidirectional power transfer ability, reduced hardware count and improved dynamic response.

  8. Can health promotion programs save Medicare money?

    Directory of Open Access Journals (Sweden)

    Ron Z Goetzel

    2007-04-01

    Full Text Available Ron Z Goetzel1, David Shechter2, Ronald J Ozminkowski1, David C Stapleton3, Pauline J Lapin4, J Michael McGinnis5, Catherine R Gordon6, Lester Breslow71Institute for Health and Productivity Studies, Cornell University, Washington, DC; 2Health and Productivity Research, Thomson Medstat, Santa Barbara, CA; 3Cornell Institute for Policy Research, Cornell University, Washington, DC; 4Office of Research, Development, and Information, Centers for Medicare and Medicaid Services, Baltimore, MD; 5National Academy of Sciences, Institute of Medicine, The National Academies, Washington, DC; 6Office of the Director, Centers for Disease Control and Prevention, Washington, DC; 7UCLA School of Public Health, Dept. of Health Services, Los Angeles, CA, USAAbstract: The impact of an aging population on escalating US healthcare costs is influenced largely by the prevalence of chronic disease in this population. Consequently, preventing or postponing disease onset among the elderly has become a crucial public health issue. Fortunately, much of the total burden of disease is attributable to conditions that are preventable. In this paper, we address whether well-designed health promotion programs can prevent illness, reduce disability, and improve the quality of life. Furthermore, we assess evidence that these programs have the potential to reduce healthcare utilization and related expenditures for the Medicare program. We hypothesize that seniors who reduce their modifiable health risks can forestall disability, reduce healthcare utilization, and save Medicare money. We end with a discussion of a new Senior Risk Reduction Demonstration, which will be initiated by the Centers for Medicare and Medicaid Services in 2007, to test whether risk reduction programs developed in the private sector can achieve health improvements among seniors and a positive return on investment for the Medicare program.Keywords: health promotion, return on investment, Medicare, financial

  9. Application of Distributed DC/DC Electronics in Photovoltaic Systems

    Science.gov (United States)

    Kabala, Michael

    In a typical residential, commercial or utility grade photovoltaic (PV) system, PV modules are connected in series and in parallel to form an array that is connected to a standard DC/AC inverter, which is then connected directly to the grid. This type of standard installation; however, does very little to maximize the energy output of the solar array if certain conditions exist. These conditions could include age, temperature, irradiance and other factors that can cause mismatch between PV modules in an array that severely cripple the output power of the system. Since PV modules are typically connected in series to form a string, the output of the entire string is limited by the efficiency of the weakest module. With PV module efficiencies already relatively low, it is critical to extract the maximum power out of each module in order to make solar energy an economically viable competitor to oil and gas. Module level DC/DC electronics with maximum power point (MPP) tracking solves this issue by decoupling each module from the string in order for the module to operate independently of the geometry and complexity of the surrounding system. This allows each PV module to work at its maximum power point by transferring the maximum power the module is able to deliver directly to the load by either boosting (stepping up) the voltage or bucking (stepping down) the voltage. The goal of this thesis is to discuss the development of a per-module DC/DC converter in order to maximize the energy output of a PV module and reduce the overall cost of the system by increasing the energy harvest.

  10. Quasiperiodicity and Torus Breakdown in a Power Electronic DC/DC Converter

    DEFF Research Database (Denmark)

    Zhusubaliyev, Zhanybai; Soukhoterin, Evgeniy; Mosekilde, Erik

    2007-01-01

    This paper discusses the mechanisms of torus formation and torus destruction in a dc/dc converter with relay control and hysteresis. We establish a chart of the dynamical modes in the input voltage versus load resistance parameter plane. This chart displays several different torus bifurcations...

  11. DC Distribution Systems and Microgrids

    DEFF Research Database (Denmark)

    Dragicevic, Tomislav; Anvari-Moghaddam, Amjad; Quintero, Juan Carlos Vasquez

    2017-01-01

    summarized. Due to its attractive characteristics in terms of compliance with modern generation, storage and electronic load technologies, high reliability and current carrying capacity, as well as simple control, DC systems are already an indispensable part of power systems. Moreover, the existing......A qualitative overview of different hardware topologies and control systems for DC MGs has been presented in this chapter. Some challenges and design considerations of DC protections systems have also been discussed. Finally, applications of DC MGs in emerging smart grid applications have been...... challenges such as protection issues will be effectively resolved in the near future due to fast progress of semiconductor technology which is a key enabler cheap and reliable future DC solid-state protection systems. Therefore, it is the view of the author that more and more DC systems will appear...

  12. Analysis of the Coupling Behavior of PEM Fuel Cells and DC-DC Converters

    Directory of Open Access Journals (Sweden)

    Achim Kienle

    2009-03-01

    Full Text Available The connection between PEM fuel cells and common DC-DC converters is examined. The analysis is model-based and done for boost, buck and buck-boost converters. In a first step, the effect of the converter ripples upon the PEM fuel cell is shown. They introduce oscillations in the fuel cell. Their appearance is explained, discussed and possibilities for their suppression are given. After that, the overall behaviors of the coupled fuel cell-converter systems are analyzed. It is shown, that neither stationary multiplicities nor oscillations can be introduced by the couplings and therefore separate control approaches for both the PEMFC and the DC-DC converters are applicable.

  13. Research of Compound Control for DC Motor System Based on Global Sliding Mode Disturbance Observer

    Directory of Open Access Journals (Sweden)

    He Zhang

    2014-01-01

    Full Text Available Aiming at the problems of modeling errors, parameter variations, and load moment disturbances in DC motor control system, one global sliding mode disturbance observer (GSMDO is proposed based on the global sliding mode (GSM control theory. The output of GSMDO is used as the disturbance compensation in control system, which can improve the robust performance of DC motor control system. Based on the designed GSMDO in inner loop, one compound controller, composed of a feedback controller and a feedforward controller, is proposed in order to realize the position tracking of DC motor system. The gains of feedback controller are obtained by means of linear quadratic regulator (LQR optimal control theory. Simulation results present that the proposed control scheme possesses better tracking properties and stronger robustness against modeling errors, parameter variations, and friction moment disturbances. Moreover, its structure is simple; therefore it is easy to be implemented in engineering.

  14. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Claudio H. Rivetta et al.

    2001-09-24

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

  16. Area-Efficiency Trade-Offs in Integrated Switched-Capacitor DC-DC Converters

    DEFF Research Database (Denmark)

    Spliid, Frederik Monrad; Larsen, Dennis Øland; Knott, Arnold

    2016-01-01

    This paper analyzes the relationship between efficiency and chip area in a fully integrated switched capacitor voltage divider dc-dc converter implemented in 180nm-technology and a 1/2 topology. A numerical algorithm for choosing the optimal sizes of individual components, in terms of power loss...

  17. Roles for National Guard Components: Current Thoughts and Future Possibilities

    Science.gov (United States)

    2000-04-01

    Gen Russell C. Davis, chief, National Guard Bureau, remarks at the National Chamber of Commerce , Washington, D.C., June 1999. 5 Moskos and Burk, 176...Lt Gen Russell C. Davis, chief, National Guard Bureau, remarks at the National Chamber of Commerce , Washington, D.C., June 9 1999. 5 National Guard...National Guard Bureau, remarks to the National Chamber of Commerce , Washington, D.C., June 1999, n.p. On-line. Internet, 27 February 2000, available at

  18. Device 2F112 (F-14A WST (Weapon System Trainers)) Instructor Console Review.

    Science.gov (United States)

    1983-12-01

    irdividuals adequately trained in the use of a particular trainer. ’S G. L. RICARD Scientific Officer 9., - 5 * NAVTRAEQUIPCEN 81-M-1121-1 TABLE OF...through verbal comunication with the instructors at the console. Several problems exist in the use of the flyout mismatch page. a. The automatic display...Washington, DC 20350 Washington, DC 20301 Chief of Naval Operations Commanding Officer OP-596C Air Force Office of Scientific Washington, DC 20350

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

    Science.gov (United States)

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

    2013-09-01

    Early growth response gene 2 (Egr2), which encodes a zinc finger transcription factor, is rapidly and transiently induced in various cell types independently of de novo protein synthesis. Although a role for Egr2 is well established in T-cell development, Egr2 expression and its biological function in dendritic cells (DCs) have not yet been described. Here, we demonstrate Egr2 expression during DC development, and its role in DC-mediated immune responses. Egr2 is expressed in the later stage of DC development from BM precursor cells. Even at steady state, Egr2 is highly expressed in mouse splenic DCs. Egr2-knockdown (Egr2-KD) DCs showed increased levels of major histocompatability complex (MHC) class I and II and co-stimulatory molecules, and enhanced antigen uptake and migratory capacities. Furthermore, Egr2-KD abolished SOCS1 expression and signal transducer and activator of transcription 5 (STAT5) activation during DC development, probably resulting in the enhancement of IL-12 expression and Th1 immunogenicity of a DC vaccine. DC-mediated cytotoxic T lymphocyte (CTL) activation and antitumor immunity were significantly enhanced by Egr2-KD, and impaired by Egr2 overexpression in antigen-pulsed DC vaccines. These data suggest that Egr2 acts as an intrinsic negative regulator of DC immunogenicity and can be an attractive molecular target for DC vaccine development. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. 77 FR 46185 - United States v. United Technologies Corporation and Goodrich Corporation; Proposed Final...

    Science.gov (United States)

    2012-08-02

    ...''), but smaller aircraft can use either AC or direct current (``DC''). AC generators can produce variable... Justice, Antitrust Division, Antitrust Documents Group, 450 Fifth Street NW., Suite 1010, Washington, DC... Street NW., Suite 8700, Washington, DC 20530 (telephone: (202) 307-0924). Patricia A. Brink, Director of...

  1. Impact of DC link control strategies on the power-flow convergence of integrated AC–DC systems

    Directory of Open Access Journals (Sweden)

    Shagufta Khan

    2016-03-01

    Full Text Available For the power-flow solution of integrated AC–DC systems, five quantities are required to be solved per converter, against three independent equations available. These three equations consist of two basic converter equations and one DC network equation, corresponding to each converter. Thus, for solution, two additional equations are required. These two equations are derived from the control specifications adopted for the DC link. Depending on the application, several combinations of valid control specifications are possible. A set of valid control specifications constitutes a control strategy. It is observed that the control strategy adopted for the DC link strongly affects the power-flow convergence of integrated AC–DC systems. This paper investigates how different control strategies affect the power flow convergence of integrated AC–DC systems. Sequential method is used to solve the DC variables in the Newton Raphson (NR power flow model. Seven typical control strategies have been taken into consideration. This is validated by numerous case studies carried out with multiple DC links incorporated in the IEEE 118-bus and 300-bus test systems.

  2. Annual Research Progress Report. Fiscal Year 1989. Volume 1

    Science.gov (United States)

    1989-10-01

    Surgery, New Orleans, LA, 24-28 September 1989. Elledge, E.S. Tonsillar Squamous Cell Carcinoma Metastatic to a Branchial Cleft Cyst. American Academy of...Symposium, Washington, DC, 6 May 1989. Gibbons, D.R. Spontaneous Otorrhea from Tegmen and Labryinthine Congenital Anomalies . Annual Meeting of the...Head, H.D. Surgical Therapy in the Management of Coronary Anomalies . Ann. Thor. Surg., (in press). Neurosurgery Service Goldring, S., Gregorie, E

  3. Impacts on the Voltage Profile of DC Distribution Network with DG Access

    Science.gov (United States)

    Tu, J. J.; Yin, Z. D.

    2017-07-01

    With the development of electronic, more and more distributed generations (DGs) access into grid and cause the research fever of direct current (DC) distribution network. Considering distributed generation (DG) location and capacity have great impacts on voltage profile, so use IEEE9 and IEEE33 typical circuit as examples, with DGs access in centralized and decentralized mode, to compare voltage profile in alternating and direct current (AC/DC) distribution network. Introducing the voltage change ratio as an evaluation index, so gets the general results on voltage profile of DC distributed network with DG access. Simulation shows that, in the premise of reasonable location and capacity, DC distribution network is more suitable for DG access.

  4. MILITARY RESEARCH: Researchers Target Flaws in Ballistic Missile Defense Plan.

    Science.gov (United States)

    Malakoff, D; Cho, A

    2000-06-16

    More than three dozen scientists journeyed to Washington, D.C., this week to warn lawmakers that a proposed $60 billion U.S. missile defense system, designed to knock incoming warheads out of the sky, is technically flawed because it can't pick out real warheads from decoys. Pentagon officials heatedly deny a new report by one scientist that contractors have rigged trials to hide the problem, although they admit that some tests were simplified to save time. In the wake of these events, a leading Democrat is urging President Bill Clinton to delay a pending decision on building the system.

  5. 75 FR 47820 - Generic Drug User Fee; Public Meeting; Request for Comments

    Science.gov (United States)

    2010-08-09

    ... Hilton Washington DC/ Rockville and Executive Meeting Center, 1750 Rockville Pike, Rockville, MD 20852... 17, 2010, at the Hilton Washington DC/Rockville and Executive Meeting Center, see Location). In...

  6. 75 FR 67721 - Proposed Agency Information Collection Activities; Comment Request

    Science.gov (United States)

    2010-11-03

    ...), Division of Research and Statistics, Board of Governors of the Federal Reserve System, Washington, DC 20551... well as securitized auto loan delinquencies and charge-offs. The accounting changes brought about by...

  7. Investigation of DC-DC Boost Converter for Reliability of Operational Planning

    DEFF Research Database (Denmark)

    Khazraj, Hesam; Ashouri, Mani; Silva, Filipe Miguel Faria da

    2018-01-01

    of the interests related to reliability is the power semiconductor switches, which are the most vulnerable elements. The failure of one-power switches can reduce the system reliability. Interleaved technique for DC-DC converters is a redundant strategy to improve the reliability, but at the cost of increasing...

  8. Comparison of the Effects of Various Irrigating Solutions on Dentine Permeability.

    Science.gov (United States)

    1980-09-01

    during intra-appointment periods. Therefore, in cases of flare -up, further instrumentation with irrigation may be more effective than irrigation alone...contents than irrigation alone. . . t , . . ’ ,... ... ’ . ,. . . .. Dr. Cecic is a second year endodontic resident at Madigan Army Medical Center, Tacoma...Washington; Dr. Peters is assistant director, endodontic residency program, US Army Institute of Dental Research, Washington, DC; and Dr. Grower is

  9. Willingness of community-recruited men who have sex with men in Washington, DC to use long-acting injectable HIV pre-exposure prophylaxis.

    Directory of Open Access Journals (Sweden)

    Matthew E Levy

    Full Text Available Clinical trials are currently investigating the safety and efficacy of long-acting injectable (LAI agents as HIV pre-exposure prophylaxis (PrEP. Using National HIV Behavioral Surveillance data, we assessed the self-reported willingness of men who have sex with men (MSM to use LAI PrEP and their preference for LAI versus daily oral PrEP.In 2014, venue-based sampling was used to recruit MSM aged ≥18 years in Washington, DC. Participants completed an interviewer-administered survey followed by voluntary HIV testing. This analysis included MSM who self-reported negative/unknown HIV status at study entry. Correlates of being "very likely" to use LAI PrEP and preferring it to daily oral PrEP were identified using multivariable logistic regression.Of 314 participants who self-reported negative/unknown HIV status, 50% were <30 years old, 41% were non-Hispanic Black, 37% were non-Hispanic White, and 14% were Hispanic. If LAI PrEP were offered for free or covered by health insurance, 62% were very likely, 25% were somewhat likely, and 12% were unlikely to use it. Regarding preferred PrEP modality, 67% chose LAI PrEP, 24% chose oral PrEP, and 9% chose neither. Correlates of being very likely versus somewhat likely/unlikely to use LAI PrEP included age <30 years (aOR 1.64; 95% CI 1.00-2.68, reporting ≥6 (vs. 1 sex partners in the last year (aOR 2.60; 95% CI 1.22-5.53, previous oral PrEP use (aOR 3.67; 95% CI 1.20-11.24, and being newly identified as HIV-infected during study testing (aOR 4.83; 95% CI 1.03-22.67. Black (vs. White men (aOR 0.48; 95% CI 0.24-0.96 and men with an income of <$20,000 (vs. ≥$75,000; aOR 0.37; 95% CI 0.15-0.93 were less likely to prefer LAI to oral PrEP.If LAI PrEP were found to be efficacious, its addition to the HIV prevention toolkit could facilitate more complete PrEP coverage among MSM at risk for HIV.

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

    Science.gov (United States)

    2010-08-05

    ... Airworthiness Directives; McDonnell Douglas Corporation Model DC- 9-10 Series Airplanes, DC-9-30 Series... existing airworthiness directive (AD), which applies to all McDonnell Douglas Model DC-9-10 series..., 2010). That AD applies to all McDonnell Douglas Corporation Model DC-9-10 series airplanes, DC-9-30...

  11. High voltage direct current transmission converters, systems and DC grids

    CERN Document Server

    Jovcic, Dragan

    2015-01-01

    This comprehensive reference guides the reader through all HVDC technologies, including LCC (Line Commutated Converter), 2-level VSC and VSC HVDC based on modular multilevel converters (MMC) for an in-depth understanding of converters, system level design, operating principles and modeling. Written in a tutorial style, the book also describes the key principles of design, control, protection and operation of DC transmission grids, which will be substantially different from the practice with AC transmission grids. The first dedicated reference to the latest HVDC technologies and DC grid developments; this is an essential resource for graduate students and researchers as well as engineers and professionals working on the design, modeling and operation of DC grids and HVDC.

  12. Attitudes, perceptions and behaviours towards HIV testing among African-American and East African immigrant women in Washington, DC: implications for targeted HIV testing promotion and communication strategies.

    Science.gov (United States)

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

    2015-12-01

    The objective of the study was to examine and compare the HIV testing attitudes, perceptions and behaviours between African-American and East African immigrant women in the Washington, DC metropolitan area. Adopting an inductive, qualitative methodological approach, we conducted a total of 40 in-depth, semistructured interviews between October 2012 and March 2013. Qualitative thematic analysis was used to analyse the data. Overall, African-American women held more favourable views towards 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-related or employment-related purposes. There were many barriers that impede women from seeking an HIV test including negative assumptions (eg, "Getting an HIV test implies that I am HIV positive"), negative emotions (eg, "Fear of being diagnosed with HIV and what this will mean for me") and potential negative reactions from partner or others (eg, "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. 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. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  13. The 2003 NASA Faculty Fellowship Program Research Reports

    Science.gov (United States)

    Nash-Stevenson, S. K.; Karr, G.; Freeman, L. M.; Bland, J. (Editor)

    2004-01-01

    For the 39th consecutive year, the NASA Faculty Fellowship Program (NFFP) was conducted at Marshall Space Flight Center. The program was sponsored by NASA Headquarters, Washington, DC, and operated under contract by The University of Alabama in Huntsville. In addition, promotion and applications are managed by the American Society for Engineering Education (ASEE) and assessment is completed by Universities Space Research Association (USRA). The nominal starting and finishing dates for the 10-week program were May 27 through August 1, 2003. The primary objectives of the NASA Faculty Fellowship Program are to: (1) Increase the quality and quantity of research collaborations between NASA and the academic community that contribute to NASA s research objectives; (2) provide research opportunities for college and university faculty that serve to enrich their knowledge base; (3) involve students in cutting-edge science and engineering challenges related to NASA s strategic enterprises, while providing exposure to the methods and practices of real-world research; (4) enhance faculty pedagogy and facilitate interdisciplinary networking; (5) encourage collaborative research and technology transfer with other Government agencies and the private sector; and (6) establish an effective education and outreach activity to foster greater awareness of this program.

  14. A Novel Single Switch Transformerless Quadratic DC/DC Buck-Boost Converter

    DEFF Research Database (Denmark)

    Mostaan, Ali; A. Gorji, Saman; N. Soltani, Mohsen

    2017-01-01

    A novel quadratic buck-boost DC/DC converter is presented in this study. The proposed converter utilizes only one active switch and can step-up/down the input voltage, while the existing single switch quadratic buck/boost converters can only work in step-up or step-down mode. First, the proposed ...

  15. 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 tolera...... tolerance, influence of temperature and stray capacitance are analyzed. It is concluded that the largest impact on sensitivity is given by reverse recovery charge variation and differences of temperature between adjacent devices....

  16. Operation and control of a DC-grid offshore wind farm under DC transmission system faults

    DEFF Research Database (Denmark)

    Deng, Fujin; Chen, Zhe

    2013-01-01

    . Consequently, the protection and control strategies of dc systems need to be established. This paper studies a dc-grid offshore wind farm, where the wind power collection system and power transmission system adopt dc technology. In this paper, the redundancy of the HVDC transmission system under faults...... is studied, and a fault ridethrough strategy for the dc-grid offshore wind farm is proposed. The proposed strategy can effectively minimize the impacts of the power transmission system disturbance on the offshore wind farm, and on the ac grid. A dc-grid offshore wind farm example is simulated with PSCAD....../EMTDC, and the results validate the feasibility of the presented redundancy configuration and operation approach, and the fault ridethrough control strategy....

  17. Selection of the DC-60 cyclotron as the basic facility for the Inter-disciplinary research complex in the L.N. Gumilev Eurasian State University. Chapter 2

    International Nuclear Information System (INIS)

    2003-01-01

    In the Chapter 2 the DC-60 specialized accelerator project of the Inter-disciplinary research complex in the L.N. Gumilev Eurasian State University is described. The DC-60 cyclotron is intended for applied studies which can be accomplished on both the ion beams of the electron cyclotron resonance source with voltage up to 25 kV and the accelerated ions from carbon to xenon. The cyclotron is design on the base of compact magnet with weight about 74 tonnes, and it mean magnetic field is 1.6 T, section angle - 50 Deg. Design of the Inter-disciplinary research complex building in the L.N. Gumilev Eurasian State University is described as well. Technical performances of the building and their parameters are given

  18. Open- and Short-Circuit Fault Identification for a Boost dc/dc Converter in PV MPPT Systems

    Directory of Open Access Journals (Sweden)

    Diego R. Espinoza Trejo

    2018-03-01

    Full Text Available This paper proposes a fault identification system for short and open-circuit switch faults (SOCSF for a dc/dc converter acting as a Maximum Power Point Tracker (MPPT in Photovoltaic (PV systems. A closed-loop operation is assumed for the boost dc/dc converter. A linearizing control plus a Proportional-Derivative (PD controller is suggested for PV voltage regulation at the maximum power point (MPP. In this study, the SOCSF are modeled by using an additive fault representation and the fault identification (FI system is synthesized departing from a Luenberger observer. Hence, an FI signal is obtained, which is insensitive to irradiance and load current changes, but affected by the SOCSF. For FI purposes, only the sensors used in the control system are needed. Finally, an experimental evaluation is presented by using a solar array simulator dc power supply and a boost dc/dc converter of 175 W in order to validate the ideas this study exposes.

  19. Proceedings of the 7th US/German Workshop on Salt Repository Research, Design, and Operation.

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Francis D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Steininger, Walter [Karisruhe Inst. of Technology (Germany); Bollingerfehr, Willhelm [DBE TECHNOLOGY GmbH (Germany)

    2017-01-01

    The 7th US/German Workshop on Salt Repository Research, Design, and Operation was held in Washington, DC on September 7-9, 2016. Over fifty participants representing governmental agencies, internationally recognized salt research groups, universities, and private companies helped advance the technical basis for salt disposal of radioactive waste. Representatives from several United States federal agencies were able to attend, including the Department of Energy´s Office of Environmental Management and Office of Nuclear Energy, the Environmental Protection Agency, the Nuclear Regulatory Commission, and the Nuclear Waste Technical Review Board. A similar representation from the German ministries showcased the covenant established in a Memorandum of Understanding executed between the United States and Germany in 2011. The US/German workshops´ results and activities also contribute significantly to the Nuclear Energy Agency Salt Club repository research agenda.

  20. Pulsed-DC selfsputtering of copper

    International Nuclear Information System (INIS)

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

    2008-01-01

    At standard magnetron sputtering conditions (argon pressure ∼0.5 Pa) inert gas particles are often entrapped in the formed films. Inert gas contamination can be eliminated by using the self-sustained magnetron sputtering process because it is done in the absence of the inert gas atmosphere. The self-sustained sputtering (SSS) gives also a unique condition during the transport of sputtered particles to the substrate. It is especially useful for filling high aspect ratio submicron scale structures for microelectronics. So far it has been shown that the self-sputtering process can be sustained in the DC operation mode (DC-SSS) only. The main disadvantage of DC-SSS process is instability related to possible arc formation. Usage of pulsed sputtering, similarly to reactive pulsed magnetron sputtering, could eliminate this problem. In this paper results of pulsed-DC self-sustained magnetron sputtering (pulsed DC-SSS) of copper are presented for the first time. The planar magnetron equipped with a 50 mm in diameter and 6 mm thick copper target was powered by DC-power supply modulated by power switch. The maximum target power was about 11 kW (∼550W/cm 2 ). The magnetron operation was investigated as a function of pulsing frequency (20-100 kHz) and duty factor (50-90%). The discharge extinction pressure was determined for these conditions. The plasma emission spectra (400-410nm range) and deposition rates were observed for both DC and pulsed DC sustained self-sputtering processes. The presented results illustrate that stable pulsed DC-SSS process can be obtained at pulsing frequency in the range of 60-100 kHz and duty factor of 70-90%

  1. Pulsed-DC selfsputtering of copper

    Science.gov (United States)

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

    2008-03-01

    At standard magnetron sputtering conditions (argon pressure ~0.5 Pa) inert gas particles are often entrapped in the formed films. Inert gas contamination can be eliminated by using the self-sustained magnetron sputtering process because it is done in the absence of the inert gas atmosphere. The self-sustained sputtering (SSS) gives also a unique condition during the transport of sputtered particles to the substrate. It is especially useful for filling high aspect ratio submicron scale structures for microelectronics. So far it has been shown that the self-sputtering process can be sustained in the DC operation mode (DC-SSS) only. The main disadvantage of DC-SSS process is instability related to possible arc formation. Usage of pulsed sputtering, similarly to reactive pulsed magnetron sputtering, could eliminate this problem. In this paper results of pulsed-DC self-sustained magnetron sputtering (pulsed DC-SSS) of copper are presented for the first time. The planar magnetron equipped with a 50 mm in diameter and 6 mm thick copper target was powered by DC-power supply modulated by power switch. The maximum target power was about 11 kW (~550W/cm2). The magnetron operation was investigated as a function of pulsing frequency (20-100 kHz) and duty factor (50-90%). The discharge extinction pressure was determined for these conditions. The plasma emission spectra (400-410nm range) and deposition rates were observed for both DC and pulsed DC sustained self-sputtering processes. The presented results illustrate that stable pulsed DC-SSS process can be obtained at pulsing frequency in the range of 60-100 kHz and duty factor of 70-90%.

  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. 78 FR 13358 - National Institute of Mental Health; Notice of Closed Meetings

    Science.gov (United States)

    2013-02-27

    ... Washington, DC, 2401 M Street, NW., Washington, DC 20037. Contact Person: Rebecca C Steiner, Ph.D..., (Telephone Conference Call). Contact Person: Rebecca C Steiner, Ph.D., Scientific Review Officer, Division of...

  4. DC Vs AC - War Of Currents For Future Power Systems A HVDC Technology Overview

    Directory of Open Access Journals (Sweden)

    Anil K. Rai

    2015-08-01

    Full Text Available DC vs AC discussion began in 1880s with development of first commercial power transmission in Wall Street New York. Later when AC technology came into notice by efforts of inventor and researcher Sir Nicola Tesla soon the advantages of AC transmission and AC devices overtook the DC technology. It was hoped that DC technology had lost battle of currents. Today with researches going on FACTS devices and bulk power transmission HVDC has again gained a reputation in power sector. Solution of this centuries old debate is to develop HVDC systems that assists HVAC systems for better performance stability and control

  5. Transition towards DC micro grids: From an AC to a hybrid AC and DC energy infrastructure

    Directory of Open Access Journals (Sweden)

    Evi Ploumpidou

    2017-12-01

    Full Text Available Our electricity is predominantly powered by alternating current (AC, ever since the War of Currents ended in the favor of Nicola Tesla at the end of the 19th century. However, lots of the appliances we use, such as electronics and lights with light-emitting diode (LED technology, work internally on direct current (DC and it is projected that the number of these appliances will increase in the near future. Another contributor to the increase in DC consumption is the ongoing electrification of mobility (Electric Vehicles (EVs. At the same time, photovoltaics (PV generate DC voltages, while the most common storage technologies also use DC. In order to integrate all these appliances and technologies to the existing AC grid, there is a need for converters which introduce power losses. By distributing DC power to DC devices instead of converting it to AC first, it is possible to avoid substantial energy losses that occur every time electricity is converted. This situation initiated the concept for the implementation of the DC-Flexhouse project. A prototype DC installation will be developed and tested in one of the buildings of the developing living lab area called the District of Tomorrow (De Wijk van Morgen which is located in Heerlen, the Netherlands. A neighborhood cooperative (Vrieheide cooperatie is also part of the consortium in order to address the aspect of social acceptance. Although DC seems to be a promising solution for a more sustainable energy system, the business case is still debatable due to both technology- and market-related challenges. The current energy infrastructure is predominantly based on AC, manufacturers produce devices based on AC standards and people are using many AC products across a long life span. This Smart Energy Buildings & Cities (SEB&C PDEng project is a contribution to the DC-Flexhouse project. The aim is to analyze the challenges in the transition to DC micro grids, assess the market potential of DC

  6. Socrates in Washington, D.C.

    Science.gov (United States)

    2008-08-01

    neoclassical architecture , his flowing robes practically blended in. At any rate, he didn’t get more than a passing glance from the pedes- trians and...American cinema and TV. “And I do believe it was this same Hawkeye who said, ‘If we don’t go crazy once in a while, we’ll all go crazy.’” We settled down

  7. 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.

  8. High voltage dc cables

    Energy Technology Data Exchange (ETDEWEB)

    Bjustrom, B

    1965-12-01

    How stress distribution in dc cables varies with temperature and stress level, influence of polarity reversals and space charges, and different types of overvoltage to which dc cable may be subjected are discussed. Design problems, especially as related to corrosion protection and to mechanical stress caused by wire armoring during manufacturing and laying, accessories and work done on test methods, and the possibility of designing 400 to 600 kV dc cables for transmitting 2000 to 4000 MW are described.

  9. Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) for Clinical and Research Applications

    DEFF Research Database (Denmark)

    Schiffman, Eric; Ohrbach, Richard; Truelove, Edmond

    2014-01-01

    of the literature providing valid instruments that, relative to the RDC/TMD, are shorter in length, are available in the public domain, and currently are being used in medical settings. RESULTS: The newly recommended Diagnostic Criteria for TMD (DC/TMD) Axis I protocol includes both a valid screener for detecting...

  10. Programming microphysiological systems for children's health protection (SEBM meeting)

    Science.gov (United States)

    Presentation: Programming microphysiological systems for children’s health protectionAuthors: Knudsen1 T, Klieforth2 B, and Slikker3 W Jr.1National Center for Computational Toxicology/EPA, Research Triangle Park NC2National Center for Environmental Research/EPA, Washington DC3Nat...

  11. Comparative evaluation of bidirectional dual active bridge DC-DC converter variants

    NARCIS (Netherlands)

    Sfakianakis, G.; Everts, J.; Huisman, H.; Lomonova, E.A.

    2016-01-01

    For the realization of DC-DC converters in automotive industry, the Dual Active Bridge (DAB) converter seems to be a promising choice because of its soft-switching and high-power-density capability. Contrary to the traditional 3 level - 3 level (3-3L) DAB, a 3 level - 5 level (3-5L) DAB can operate

  12. Improvement of burst-mode control of piezoelectric transformer based DC/DC converter

    International Nuclear Information System (INIS)

    Vasic, Dejan; Liu, Yuan-Ping; Costa, François; Schwander, Denis; Wu, Wen-Jong

    2013-01-01

    Burst-mode operation is adopted sometimes in piezoelectric transformer based converters for two major purposes: (1) to achieve voltage regulation in DC/DC converters and (2) to achieve dimming control in backlight inverters. Burst-mode control enables the converter to operate at a constant switching frequency as well as to maintain good efficiency at light load conditions. However, in practice, the piezoelectric transformer cannot instantly stop vibrating in the burst-mode due to its high quality factor. The delay in the output voltage change resulting from this behavior influences the accuracy of the regulation. This paper proposes a control strategy to make the piezoelectric transformer stop more quickly so as to enhance the accuracy of burst-mode control. The proposed method only modifies the control signal of the burst-mode driving circuit. The proposed control strategy is verified by experiments in a step-down 9 W DC/DC converter. (paper)

  13. 78 FR 33691 - Distribution of Source Material to Exempt Persons and to General Licensees and Revision of...

    Science.gov (United States)

    2013-06-05

    ..., Washington, DC 20555-0001, telephone: 301-415- 8106, email: [email protected] or Tomas Herrera, Office of..., Washington, DC 20555-0001, telephone: 301-415- 7138, email: Tomas.Herrera@nrc.gov . SUPPLEMENTARY INFORMATION...

  14. Modular Power System Configured with Standard Product Hybrid DC-DC Converters, Phase II

    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...

  15. 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...

  16. Effects of DC bias on magnetic performance of high grades grain-oriented silicon steels

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Guang; Cheng, Ling [Global Energy Interconnection Research Institute, State Key Laboratory of Advanced Transmission Technology,Beijing 102211 (China); Lu, Licheng [State Grid Corporation of China, Beijing 100031 (China); Yang, Fuyao; Chen, Xin [Global Energy Interconnection Research Institute, State Key Laboratory of Advanced Transmission Technology,Beijing 102211 (China); Zhu, Chengzhi [State Grid Zhejiang Electric Power Company, Hangzhou 310007 (China)

    2017-03-15

    When high voltage direct current (HVDC) transmission adopting mono-polar ground return operation mode or unbalanced bipolar operation mode, the invasion of DC current into neutral point of alternating current (AC) transformer will cause core saturation, temperature increasing, and vibration acceleration. Based on the MPG-200D soft magnetic measurement system, the influence of DC bias on magnetic performance of 0.23 mm and 0.27 mm series (P{sub 1.7}=0.70–1.05 W/kg, B{sub 8}>1.89 T) grain-oriented (GO) silicon steels under condition of AC / DC hybrid excitation were systematically realized in this paper. For the high magnetic induction GO steels (core losses are the same), greater thickness can lead to stronger ability of resisting DC bias, and the reasons for it were analyzed. Finally, the magnetostriction and A-weighted magnetostriction velocity level of GO steel under DC biased magnetization were researched. - Highlights: • Magnetic properties of 0.23 mm and 0.27 mm series (P{sub 1.7}=0.70–1.05 W/kg, B{sub 8}>1.89 T) grain-oriented (GO) silicon steels under condition of AC / DC hybrid excitation were systematically analyzed. • Influence of DC biased magnetization on core loss, magnetostriction, and A-weighted magnetostriction velocity level of GO steel were researched. • Greater thickness and relatively lower magnetic induction (B{sub 8}>1.89 T yet) of GO steel can lead to stronger ability of resisting DC bias, and the reasons for it were analyzed.

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

    Science.gov (United States)

    2013-06-01

    future pulse power demands with ship power, a large bank of capacitors or similar rapid discharge source is required. If capacitors are charged...Single Pulsed Avalanche Energy (j) I" Avalanche Current (i) E,, Repetilive Avalanche Energy (i) dv/dt Peak Diode Recovery dv/dt ® Po Total Power...SLR), battery charging, DC-DC, pulse power, power electronics, SLR converter 15. NUMBER OF PAGES 119 16. PRICE CODE 17. SECURITY CLASSIFICATION

  18. Efficient Visible Light Communication Transmitters Based on Switching-Mode dc-dc Converters

    Science.gov (United States)

    2018-01-01

    Visible light communication (VLC) based on solid-state lighting (SSL) is a promising option either to supplement or to substitute existing radio frequency (RF) wireless communication in indoor environments. VLC systems take advantage of the fast modulation of the visible light that light emitting diodes (LEDs) enable. The switching-mode dc-to-dc converter (SMCdc-dc) must be the cornerstone of the LED driver of VLC transmitters in order to incorporate the communication functionality into LED lighting, keeping high power efficiency. However, the new requirements related to the communication, especially the high bandwidth that the LED driver must achieve, converts the design of the SMCdc-dc into a very challenging task. In this work, three different methods for achieving such a high bandwidth with an SMCdc-dc are presented: increasing the order of the SMCdc-dc output filter, increasing the number of voltage inputs, and increasing the number of phases. These three strategies are combinable and the optimum design depends on the particular VLC application, which determines the requirements of the VLC transmitter. As an example, an experimental VLC transmitter based on a two-phase buck converter with a fourth-order output filter will demonstrate that a bandwidth of several hundred kilohertz (kHz) can be achieved with output power levels close to 10 W and power efficiencies between 85% and 90%. In conclusion, the design strategy presented allows us to incorporate VLC into SSL, achieving high bit rates without damaging the power efficiency of LED lighting. PMID:29642455

  19. 76 FR 51375 - Dialogues in Diversifying Clinical Trials: Successful Strategies for Engaging Women and...

    Science.gov (United States)

    2011-08-18

    ... implementation within a broad research community--industry, academia, and government. Date and Time: The meeting... will be held at L'Enfant Plaza Hotel, 480 L'Enfant Plaza, SW., Washington, DC 20024. Contact: Deborah...

  20. Models to predict suitable habitat for juvenile bull trout in Washington state

    Science.gov (United States)

    Jason B. Dunham; G. L. Chandler

    2001-01-01

    This report describes results of research conducted in 2000 to develop models of suitable habitat for juvenile bull trout (Salvelinus confluentus) in Washington State. The research is associated with a cooperative agreement (Agreement #134100H001) between U.S. Fish and Wildlife Service (USFWS) and the U.S. Forest Service, Rocky Mountain Research...