Sample records for residence hall agreement

  1. Facility Focus: Residence Halls. (United States)

    College Planning & Management, 2003


    Describes four examples of residence hall design, one renovation and three new residence halls, that exemplify design principles that meet student and institutional requirements. The examples are at (1) the University of Illinois at Chicago; (2) Bowdoin College; (3) Muhlenberg College; and (4) Spring Arbor University. (SLD)

  2. Invitational Engineering in the Residence Halls. (United States)

    Murphy, Jack; Purkey, William


    Presents various ways in which a residence hall environment may be specifically engineered to encourage individual participation in the process of education. Invitational engineering is defined as one way to transpose psychological principles to residence halls so they contribute to the developmental life of students. (RC)

  3. 20th Annual Residence Hall Construction Report (United States)

    Agron, Joe


    Even in difficult economic times, colleges and universities continue to invest in residence hall construction projects as a way to attract new students and keep existing ones on campus. According to data from "American School & University"'s 20th annual Residence Hall Construction Report, the median new project completed in 2008 was…

  4. Judicious Leadership for Residence Hall Living. (United States)

    Gathercoal, Forrest

    This book presents a theory of judicious leadership for residence hall management that advocates the creation of an ethical and educational perspective based on the U.S. Bill of Rights. It argues that by recognizing college students' citizenship rights, providing them an opportunity to experience individual liberties, and helping them to…

  5. A NACURH White Paper on Residence Hall Government. (United States)

    Wyatt, Kevin W.; Stoner, Kenneth L.


    Presents a white paper on residence hall government, summarizing fundamental principles in organizing and maintaining a residence hall association on campus. These include determining needs, identifying support, obtaining income, ensuring effective leadership, and developing system maintenance. (JAC)

  6. A Business-Oriented Student Program: Residence Hall Stores. (United States)

    Valerio, Vance R.


    Describes a residence hall store program which provides prepackaged food and snacks to students at Marquette University. Results of a survey of 21 colleges which have residence hall stores revealed primarily informal organizations. Stores can be a successful student development technique which teaches principles of small-business management. (JAC)

  7. The Marketing of Residence Halls: A Question of Positioning. (United States)

    Parker, R. Stephen; And Others


    A survey of 343 college residence hall directors revealed percentages of private and public institutions offering different amenities, main selling points in promotional brochures, and the most common resident complaints. Results were compared with those of a resident survey concerning the importance of various housing attributes. Implications for…

  8. Involving Students in Residence Halls in Hong Kong (United States)

    Ting, S. Raymond; Chan, Rebecca; Lee, Esther


    This article reports a study based on A. W. Astin's (1984) involvement theory applied in residence halls at a public university in Hong Kong, China. The resident students who were involved as participants or student leaders in this study were found to be better developed in terms of leadership, career development, multicultural experience,…

  9. Living and Learning: "Does Residence Hall Roommate Placement of Traditional Freshman Students at MSOE Effect Their Satisfaction with the Residence Halls?" (United States)

    Breese, William Ellis, II


    The purpose of this study is to examine if residence hall roommate placement of traditional freshman students at MSOE affects their satisfaction with the residence halls. The idea behind this study is that if residence hall roommate placement is done purposefully, with the participation of incoming freshmen through appropriate placement…

  10. Investigating Black Gay Male Undergraduates' Experiences in Campus Residence Halls (United States)

    Strayhorn, Terrell L.; Mullins, Taris G.


    This qualitative study sought to understand the challenges that Black gay male undergraduates confront in campus residence halls and the supports that enabled their success in facing them. Drawing on in-depth interviews with 29 participants, we found that Black gay men report varied encounters with subtle and overt forms of racism among White…

  11. The Role of Social Influence on How Residence Hall Inhabitants Respond to Fire Alarms (United States)

    Leytem, Michael; Stark, Emily


    College resident halls pose a threat for a catastrophic event in the case of fire, but little research has examined potential influences on students' responses to fire alarms, particularly the role of social influence in affecting their behaviors. In the current study, residence hall inhabitants reported their knowledge about fire safety, their…

  12. "Are You as Hard as 50 Cent?" Negotiating Race and Masculinity in the Residence Halls (United States)

    Jaggers, Dametraus; Iverson, Susan V.


    In a qualitative study of Black undergraduate men at a predominantly White university in the Midwest, participants shared their experiences in residence halls, including roommate conflicts, interracial tensions, and disagreements with residence hall staff. This article focuses on Black male undergraduates' negotiation of racialized conceptions of…

  13. "Are You as Hard as 50 Cent? Negotiating Race and Masculinity in the Residence Halls (United States)

    Jaggers, Dametraus; Iverson, Susan V.


    In a qualitative study of Black undergraduate men at a predominantly White university in the Midwest, participants shared their experiences in residence halls, including roommate conflicts, interracial tensions, and disagreements with residence hall staff. This article focuses on Black male undergraduates' negotiation of racialized conceptions of…

  14. Alcohol Trajectories over Three Years in a Swedish Residence Hall Student Population

    Directory of Open Access Journals (Sweden)

    Henriettae Ståhlbrandt


    Full Text Available Although it is known that college students have a high alcohol consumption, less is known about the long-term drinking trajectories amongst college students and, in particular, students living in residence halls, known to be high-risk drinkers. Over four consecutive years, the drinking habits of 556 Swedish residence hall students were analyzed. The main instruments for measuring outcome were AUDIT (Alcohol Use Identification Disorders Test, SIP (Short Index of Problems and eBAC (estimated Blood Alcohol Concentration. The drinking trajectories among Swedish residence hall students showed stable and decreasing drinking patterns, with age and gender being predictors of group membership.

  15. Alcohol trajectories over three years in a Swedish residence hall student population. (United States)

    Ståhlbrandt, Henriettae; Leifman, Anders; Johnsson, Kent O; Berglund, Mats


    Although it is known that college students have a high alcohol consumption, less is known about the long-term drinking trajectories amongst college students and, in particular, students living in residence halls, known to be high-risk drinkers. Over four consecutive years, the drinking habits of 556 Swedish residence hall students were analyzed. The main instruments for measuring outcome were AUDIT (Alcohol Use Identification Disorders Test), SIP (Short Index of Problems) and eBAC (estimated Blood Alcohol Concentration). The drinking trajectories among Swedish residence hall students showed stable and decreasing drinking patterns, with age and gender being predictors of group membership.

  16. Alcohol Trajectories over Three Years in a Swedish Residence Hall Student Population (United States)

    Ståhlbrandt, Henriettae; Leifman, Anders; Johnsson, Kent O.; Berglund, Mats


    Although it is known that college students have a high alcohol consumption, less is known about the long-term drinking trajectories amongst college students and, in particular, students living in residence halls, known to be high-risk drinkers. Over four consecutive years, the drinking habits of 556 Swedish residence hall students were analyzed. The main instruments for measuring outcome were AUDIT (Alcohol Use Identification Disorders Test), SIP (Short Index of Problems) and eBAC (estimated Blood Alcohol Concentration). The drinking trajectories among Swedish residence hall students showed stable and decreasing drinking patterns, with age and gender being predictors of group membership. PMID:20617038

  17. Student Development in a Coed Residence Hall: Promiscuity, Prophylactic, or Panacea? (United States)

    Brown, Robert D.; And Others


    The results of this study on evaluation of coed residence halls, indicate that a coed hall can lead to an entirely different environment, one that is a contributing factor in positive student development. This paper was presented at the APGA Convention, Chicago, Illinois, 1972. (JC)

  18. Reflections of a Professor on Nine Years of Living in the Dorms ... I Mean Residence Halls! (United States)

    Rhoads, Robert A.


    Faculty-in-residence programs aim to strengthen the intellectual climate in residential facilities. This article presents the author's reflections on nine years of living in a residence hall as a Faculty-In-Residence (FIR) at the University of California, Los Angeles (UCLA). The author shares an insider's observations on the role he played as a…

  19. Style of Life and Student Personnel Policy in College Residence Halls (United States)

    White, Julie E.


    Doctoral dissertation, Dimensions of Conformity and Evasion in Residence Halls for University Women: A Sociological Analysis of Normative Behavior in a Large-Scale Social Organization, 1962, University of Illinois, Urbana.

  20. A Policy Analysis of Missouri Community College Residence Hall Discipline Policies with an Analysis of Changes in the State Fair Community College Residence Hall Policy (United States)

    Gilgour, Joseph G.


    Community colleges in the United States have long been known as institutions of equal opportunity and affordable education. One facet of student life appearing at more and more community colleges is the addition of residence halls. Still, the number of community colleges with on-campus living is relatively small, and for the campuses with…

  1. What Residence Hall Staff Need to Know about Dealing with Death. (United States)

    Jacobs, Bonita; Towns, James E.


    Emphasizes the responsibility for residence hall staff to understand the grief process. An adaptation of Kubler-Ross's stages of death has produced helpful techniques for successfully accepting the death. Through understanding these principles, staff can become aware of the grief process and can assist residents. (JAC)

  2. Examining the Impact Parental Educational Attainment Has on Students' Perceptions of Residence Hall Living (United States)

    Lawrie, Joshua D.


    The current study sought to examine the impact parental educational attainment had on how students perceived their residence hall environment. This multi-campus study utilized the University Residence Environment Scale, along with a demographic form to gather data. The study occurred on three campuses during the Spring 2012 semester and had 347…

  3. The Actively Caring for People Movement at Virginia Tech and Beyond: Cultivating Compassion and Relationships in Residence Halls (United States)

    McCarty, Shane M.; Mullins, Taris G.; Geller, E. Scott; Shushok, Frank, Jr.


    A professor and a group of student leaders initiated the Actively Caring for People (AC4P) Movement to establish a more civil, compassionate, and inclusive culture by inspiring intentional acts of kindness. This article explores the AC4P Movement in a first-year residence hall at Virginia Tech and a second-year residence hall at University of…

  4. Students' Sense of Community in Residence Halls, Social Integration, and First-Year Persistence. (United States)

    Berger, Joseph B.


    Used concepts from community psychology literature to elaborate a revised version of Tinto's model of individual student departure. Employed a longitudinal analysis of 718 college students. Results indicate that students' sense of community in their residence halls was a source of social integration and a precursor to student departure decisions.…

  5. Students' Perceptions of the Residence Hall Living Environment at Kuwait University (United States)

    Al Kandari, Nabila


    The purpose of this study is to explore students' perceptions of the residence hall living environment at Kuwait University. The researcher developed a questionnaire for this purpose that included 36 items. The sample of the study consisted of 191 residential students, of whom 98 were male and 93 were female. The research findings indicated that:…

  6. Students' Sense of Community Based on Experiences with Residence Hall Design (United States)

    Heasley, Christopher L.


    This study seeks to determine students' sense of community outcomes based on experiences with different residence hall architectural designs. Sense of community is a "feeling that members have of belonging, a feeling that members matter to one another and to the group, and a shared faith that members' needs will be met through their…

  7. Residence Hall Room Type and Alcohol Use among College Students Living on Campus (United States)

    Cross, Jennifer E.; Zimmerman, Don; O'Grady, Megan A.


    The objectives were to explore the relation between the built environment of residence halls and the alcohol use of college students living on campus from the perspective of the theory of routine activity. This exploratory study examined data from two samples on one college campus. Online surveys assessed alcohol use, attitudes toward alcohol use,…

  8. Residence Hall Student Satisfaction with Interim Alcohol Policy. Office for Student Affairs Research Bulletin; v15 n4 Jul74. (United States)

    Seabourg, Deborah; And Others

    At the beginning of the 1973-74 academic year alcohol usage was officially permitted for the first time in residence halls at the Twin Cities Campus of the University of Minnesota. To determine residents' perceptions of the effects of the change in drinking policy, interviews were conducted with 49 current dormitory residents, who had also lived…

  9. Fostering a Sense of Community in Residence Halls: A Role for Housing and Residential Professionals in Increasing College Student Persistence (United States)

    Erb, Natalee M.; Sinclair, Matthew S.; Braxton, John M.


    Fostering a sense of community should be at the center of every housing and residence life professional's efforts. Research conducted by Braxton et al. (2014) revealed that students who are able to identify with their residence hall community, interact with peers in this community, and find solidarity within the community experience an increased…

  10. [Food behavior in student residence halls: a setting for health promotion]. (United States)

    Alves, Hayda Josiane; Boog, Maria Cristina Faber


    To qualitatively describe food practices of students living in a residence hall. A quantitative and qualitative study was carried out in a drawn sample of 100 university students living in a residence hall in the city of Campinas, Southeastern Brazil, in 2004. Students were interviewed using a questionnaire to collect 24-hour food recall information including open questions on shopping and intake practices. Criteria were established for the analysis of meal quality. The Chi-square and the exact Fisher test were used at a 5% significance level. Representations based on Moscivici's theory of social representations were obtained in the interviews and analyzed. Assessment of 24-hour food recall: breakfast--30% of the students skipped it, 13% had full, 37% had standard and 20% had partial meal; lunch--5% skipped, 72% had full, and 23% had partial meal; dinner--1% skipped, 36% had full, and 63% had partial meal. Lunch was the best quality meal and of those who had lunch, 63% had it at the university cafeteria. Of all respondents, 48% had no fruit and 39% had no milk. Most (69%) showed an individual food behavior and 43% thought that having meals together had a positive impact on their food behavior. The experience of becoming the provider of their own food changes the students' food behaviors and representations. Diet quality, patterns of commensality and social representations of food provide input for developing healthy diet care and health promotion.

  11. Helping Students Achieve Their Goals: The Experience of Working with Students with Mental Health Concerns in a Residence Hall (United States)

    Schafer, Kevin P.


    Individuals living with a mental health issue and attending college may experience significant opportunities for growth and also personal challenges in their development into young adulthood. Residence hall directors may be instrumental in assisting this population during their college years. The purpose of this qualitative study was to examine…

  12. Being and Belonging: A Critical Phenomenological Study of Undergraduate Chinese International Students' Sense of Belonging in Residence Halls (United States)

    Yao, Christina Wai-Tze


    Despite the large number of international students from China in U.S. higher education, little research exists on these students' perceptions of the racial climate in residence halls. This research study illuminates the experiences affecting the sense of belonging of first-year Chinese international students and provides insights on how these…

  13. Sleep quality and some factors affecting sleep quality in the students living in the residence hall of a university


    Ozge Yavuz Sari; Sarp Uner; Berkem Buyukakkus; Emine Ozlem Bostanci; Aytek Huseyin Celiksoz; Mehmet Budak


    AIM: Sleep disorders are remarkable public health problems as they adversely affect physical, mental and social health and may cause accidents and decline in academic performance and labor productivity. Aim of the study is assessing sleep quality and determining some factors affecting sleep quality in the students living in the residence hall of a university. METHOD: It is a cross sectional study conducted with 277 students, 180 of whom are female. Data were collected via a questionnaire ...

  14. Using the Leaderless Group Discussion Technique for the Selection of Residence Hall Counselors (United States)

    Banta, Trudy W.; McCormick, Jane E.


    Describes successful effort to involve head residents in selection responsibilities. Discusses use of Record of Previous Leadership Experience, behavior ratings adapted from Interview and LGD Rating Scale (T. W. Banta) recommendation from head resident as selection criteria. (CJ)

  15. Sleep quality and some factors affecting sleep quality in the students living in the residence hall of a university

    Directory of Open Access Journals (Sweden)

    Ozge Yavuz Sari


    Full Text Available AIM: Sleep disorders are remarkable public health problems as they adversely affect physical, mental and social health and may cause accidents and decline in academic performance and labor productivity. Aim of the study is assessing sleep quality and determining some factors affecting sleep quality in the students living in the residence hall of a university. METHOD: It is a cross sectional study conducted with 277 students, 180 of whom are female. Data were collected via a questionnaire including Pittsburgh Sleep Quality Index (PSQI, Epworth Sleepiness Scale (ESS and socio-demographic characteristics query. RESULTS: According to PSQI, 41.1% of students have bad sleep quality. Sleep quality of male students and students who are overweight/obese or living in more crowded rooms in the hall of residence is worse than other students and #8217;. Prevalence of bad sleep quality is higher in medication users, participants thinking that they have problems in sleeping or falling asleep and had stressful experience in the last month. The differences between groups were statistically significant. In logistic regression analyzes, using medication (OR=2.54, having problems in sleep (OR=12.75, having problems in falling asleep (OR=8.83 and bad experiences in the last month (OR=2.66 have effects on sleep quality. CONCLUSIONS: Interventions about sleep disorders are important due to their preventable characteristics. Developing healthy life habits, improving physical conditions and coping with stress will be effective on preventing and treating sleep disorders. [TAF Prev Med Bull 2015; 14(2.000: 93-100

  16. Moradia universitária: processos de socialização e consumo de drogas University residence halls: socialization processes and drug consumption

    Directory of Open Access Journals (Sweden)

    Thais Helena Mourão Laranjo


    Full Text Available OBJETIVO: Conhecer e analisar o discurso dos moradores de um conjunto residencial estudantil universitário sobre os processos de socialização e consumo de drogas. MÉTODOS: Pesquisa qualitativa, realizada com 20 alunos de graduação residentes em moradia estudantil universitária em São Paulo, SP, 2003. Tomou-se a moradia como um espaço de socialização juvenil que viabiliza a presença de estudantes de baixa renda, na universidade. As entrevistas abordaram o conhecimento dos alunos sobre a história da moradia, a experiência de viver em uma moradia estudantil e a percepção dos moradores sobre o consumo de drogas. O procedimento metodológico que serviu de base para a coleta, organização e análise das entrevistas foi o discurso do sujeito coletivo. RESULTADOS: Os resultados mostraram que: os estudantes têm pouco conhecimento sobre a história da moradia; as alternativas para os problemas que enfrentam na moradia têm sido buscadas individualmente; observou-se entre os moradores as duas principais concepções de prevenção ao consumo de drogas - guerra às drogas e redução de danos. Observou-se haver uma visão negativa sobre a moradia estudantil relacionada com a constante divulgação de fatos conturbados e com o desconhecimento sobre a importância da moradia para viabilizar a permanência de estudantes pobres na universidade. CONCLUSÕES: Na opinião de seus moradores, a moradia estudantil viabiliza o acesso a universidade, apesar de dificuldades na convivência coletiva e na administração da universidade. Em relação ao uso de drogas na moradia, parte dos moradores ressalta a necessidade de menor tolerância ao consumo de drogas e outra parte destaca a importância de trabalho educativo, principalmente com os ingressantes.OBJECTIVE: To investigate and analyze the discourse of students living in university residence halls regarding socialization processes and drug consumption. METHODS: This was qualitative research among

  17. Two-Year Outcome of Alcohol Interventions in Swedish University Halls of Residence: A Cluster Randomized Trial of a Brief Skills Training Program, Twelve-Step-Influenced Intervention, and Controls.


    Ståhlbrandt, Henrietta; Johnsson, Kent; Berglund, Mats


    Background: High-risk alcohol consumption among university students is well documented. Several types of intervention have proved to be effective in reducing alcohol consumption. This study examines the 2-year outcome of 2 different alcohol intervention programs at university halls of residence. Methods: Ninety-eight university halls of residence (with 556 students) were cluster randomized to 2 different intervention groups: a brief skills training program (BSTP) with interactive lectu...

  18. An exploratory cluster randomised trial of a university halls of residence based social norms marketing campaign to reduce alcohol consumption among 1st year students. (United States)

    Moore, Graham F; Williams, Annie; Moore, Laurence; Murphy, Simon


    This exploratory trial examines the feasibility of implementing a social norms marketing campaign to reduce student drinking in universities in Wales, and evaluating it using cluster randomised trial methodology. Fifty residence halls in 4 universities in Wales were randomly assigned to intervention or control arms. Web and paper surveys were distributed to students within these halls (n = 3800), assessing exposure/contamination, recall of and evaluative responses to intervention messages, perceived drinking norms and personal drinking behaviour. Measures included the Drinking Norms Rating Form, the Daily Drinking Questionnaire and AUDIT-C. A response rate of 15% (n = 554) was achieved, varying substantially between sites. Intervention posters were seen by 80% and 43% of students in intervention and control halls respectively, with most remaining materials seen by a minority in both groups. Intervention messages were rated as credible and relevant by little more than half of students, though fewer felt they would influence their behaviour, with lighter drinkers more likely to perceive messages as credible. No differences in perceived norms were observed between intervention and control groups. Students reporting having seen intervention materials reported lower descriptive and injunctive norms than those who did not. Attention is needed to enhancing exposure, credibility and perceived relevance of intervention messages, particularly among heavier drinkers, before definitive evaluation can be recommended. A definitive evaluation would need to consider how it would achieve sufficient response rates, whilst hall-level cluster randomisation appears subject to a significant degree of contamination. ISRCTN: ISRCTN48556384.

  19. Agreements

    International Nuclear Information System (INIS)


    These columns summarize the different bilateral and multilateral agreements concluded recently between the different OECD countries and concerning the nuclear energy domain: Argentina - Australia: Agreement concerning Co-operation in the Peaceful Uses of Nuclear Energy (2001). Argentina - Brazil: Joint Declaration regarding the Creation of the Argentinean-Brazilian Agency for Nuclear Energy Applications (2001). Australia - Czech Republic / Australia - Hungary: Agreements on Co-operation in Peaceful Uses of Nuclear Energy and the Transfer of Nuclear Material (2001). Australia - Indonesia: Arrangement Concerning Co-operation on Nuclear Safeguards and Related Matters (2001). Austria - Switzerland: Agreement on the Early Exchange of Information in the Field of Nuclear Safety and Radiation. Brazil - United States: Extension of the Agreement concerning Research and Development in Nuclear Material Control, Accountancy, Verification, Physical Protection, and Advanced Containment and Surveillance Technologies for International Safeguards Applications (2001). Czech Republic - Republic of Korea: Agreement for Co-operation in the Peaceful Uses of Nuclear Energy (2001). European Union- Russian Federation: Agreements on Nuclear Safety and Controlled Nuclear Fusion (2001). France - United States: Agreement for Co-operation in Advanced Nuclear Reactor Science and Technology (2001). Japan - United Kingdom: Co-operation Agreement on Advanced Nuclear Fuel Cycle, Fast Breeder Reactor and Other Related Technologies (2001). Republic OF Korea - United States: Annex IV Joint Project on Cintichem Technology (2000). Morocco - United States: Protocol amending the Co-operation Agreement on the Peaceful Uses of Nuclear Energy (2001). Multilateral Agreements: Agreement for Information Exchange on Radiological Surveillance in Northern Europe (2001). Status of Conventions in the Field of Nuclear Energy. (author)

  20. Utility of Interobserver Agreement Statistics in Establishing Radiology Resident Learning Curves During Self-directed Radiologic Anatomy Training. (United States)

    Tureli, Derya; Altas, Hilal; Cengic, Ismet; Ekinci, Gazanfer; Baltacioglu, Feyyaz


    The aim of the study was to ascertain the learning curves for the radiology residents when first introduced to an anatomic structure in magnetic resonance images (MRI) to which they have not been previously exposed to. The iliolumbar ligament is a good marker for testing learning curves of radiology residents because the ligament is not part of a routine lumbar MRI reporting and has high variability in detection. Four radiologists, three residents without previous training and one mentor, studied standard axial T1- and T2-weighted images of routine lumbar MRI examinations. Radiologists had to define iliolumbar ligament while blinded to each other's findings. Interobserver agreement analyses, namely Cohen and Fleiss κ statistics, were performed for groups of 20 cases to evaluate the self-learning curve of radiology residents. Mean κ values of resident-mentor pairs were 0.431, 0.608, 0.604, 0.826, and 0.963 in the analysis of successive groups (P 0.8). Therefore, a junior radiology resident can obtain enough experience in identifying a rather ambiguous anatomic structure in routine MRI after a brief instruction of a few minutes by a mentor and studying approximately 80 cases by oneself. Implementing this methodology will help radiology educators obtain more concrete ideas on the optimal time and effort required for supported self-directed visual learning processes in resident education. Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.

  1. Hall Sweet Home (United States)

    Oguntoyinbo, Lekan


    Many urban and commuter universities have their sights set on students who are unlikely to connect with the college and likely to fail unless the right strategies are put in place to help them graduate. In efforts to improve retention rates, commuter colleges are looking to an unusual suspect: residence halls. The author discusses how these…

  2. What's the agreement between self-reported and biochemical verification of drug use? A look at permanent supportive housing residents. (United States)

    Rendon, Alexis; Livingston, Melvin; Suzuki, Sumihiro; Hill, Whitney; Walters, Scott


    Self-reported substance use is commonly used as an outcome measure in treatment research. We evaluated the validity of self-reported drug use in a sample of 334 adults with mental health problems who were residing in supportive housing programs. The primary analysis was the calculation of the positive predictive values (PPVs) of self-report compared to an oral fluid test taken at the same time. A sensitivity analysis compared the positive predictive values of two self-reported drug use histories: biological testing window (ranging between the past 96h to 30days depending on drug type) or the full past 90-day comparison window (maximum length recorded during interview). A multivariable logistic regression was used to predict discordance between self-report and the drug test for users. Self-reported drug use and oral fluid drug tests were compared to determine the positive predictive value for amphetamines/methamphetamines/PCP (47.1% agreement), cocaine (43.8% agreement), and marijuana (69.7% agreement) drug tests. Participants who misreported their drug use were more likely to be older, non-White, have no medical insurance, and not report any alcohol use. In general, amphetamine/methamphetamine/PCP and cocaine use was adequately captured by the biological test, while marijuana use was best captured by a combination of self-report and biological data. Using the full past 90day comparison window resulted in higher concordance with the oral fluid drug test, indicating that self-reported drug use in the past 90days may be a proxy for drug use within the biological testing window. Self-report has some disadvantages when used as the sole measure of drug use in this population. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. The agreement between proxy and self-completed EQ-5D for care home residents was better for index scores than individual domains. (United States)

    Devine, Angela; Taylor, Stephanie J C; Spencer, Anne; Diaz-Ordaz, Karla; Eldridge, Sandra; Underwood, Martin


    Proxy measures are an alternative source of data for care home residents who are unable to complete the health utility measure, but the agreement levels between residents and care home staff for the EQ-5D have not been investigated previously. The objective of the present study was to examine the inter-rater agreement levels for the reporting of EQ-5D by care home residents and staff, adjusting for the impact of clustering. The data consist of EQ-5D scores for 565 pairs of care home residents and proxies and quality-adjusted life-years (QALYs) for 248 pairs. Cluster-adjusted agreement was compared for the domains, index scores, and QALYs from the EQ-5D. Factors influencing index score agreement are also described. The results show poor to fair agreement at the domain level (cluster-adjusted Kappa -0.03 to 0.26) and moderate agreement at the score level (cluster-adjusted intra-class correlation coefficient [ICC] 0.44-0.50) and for QALYs (cluster-adjusted ICC 0.59). A higher likelihood of depression and lower cognitive impairment were both associated with smaller discrepancy between proxy and self-completed scores. Proxies appear to be an acceptable source of data for index scores and QALYs but may be less reliable if individual domains are considered. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  4. The agreement between proxy and self-completed EQ-5D for care home residents was better for index scores than individual domains☆ (United States)

    Devine, Angela; Taylor, Stephanie J.C.; Spencer, Anne; Diaz-Ordaz, Karla; Eldridge, Sandra; Underwood, Martin


    Objective Proxy measures are an alternative source of data for care home residents who are unable to complete the health utility measure, but the agreement levels between residents and care home staff for the EQ-5D have not been investigated previously. The objective of the present study was to examine the inter-rater agreement levels for the reporting of EQ-5D by care home residents and staff, adjusting for the impact of clustering. Study Design and Setting The data consist of EQ-5D scores for 565 pairs of care home residents and proxies and quality-adjusted life-years (QALYs) for 248 pairs. Cluster-adjusted agreement was compared for the domains, index scores, and QALYs from the EQ-5D. Factors influencing index score agreement are also described. Results The results show poor to fair agreement at the domain level (cluster-adjusted Kappa −0.03 to 0.26) and moderate agreement at the score level (cluster-adjusted intra-class correlation coefficient [ICC] 0.44–0.50) and for QALYs (cluster-adjusted ICC 0.59). A higher likelihood of depression and lower cognitive impairment were both associated with smaller discrepancy between proxy and self-completed scores. Conclusion Proxies appear to be an acceptable source of data for index scores and QALYs but may be less reliable if individual domains are considered. PMID:24837298

  5. Interobserver agreement between senior radiology resident, neuroradiology fellow, and experienced neuroradiologist in the rating of Alberta Stroke Program Early Computed Tomography Score (ASPECTS). (United States)

    Kobkitsuksakul, Chai; Tritanon, Oranan; Suraratdecha, Vichan


    The distribution of ischemic changes caused by infarction of the middle cerebral artery (MCA) territories is usually measured using the Alberta Stroke Program Early Computed Tomography Score (ASPECTS). The first interpreter of the brain computed tomography (CT) in the emergency department is the on-call radiology resident. The primary objective of this study was to describe the agreement of the ASPECTS performed retrospectively by the resident compared with expert raters. The second objective was to ascertain the appropriate window setting for early detection of acute ischemic stroke and good interobserver agreement between the interpreters. We identified consecutive patients presenting with hemiparesis or aphasia at the emergency department who underwent brain CT and CT angiography. Each scan was rated using ASPECTS by senior radiology resident, neuroradiology fellow, and later by consensus between two expert raters. Statistical analysis included determination of Cohen's kappa (κ) coefficient and intraclass correlation coefficient (ICC). A total of 43 patients met our study criteria. Interobserver agreements for ASPECTS varied from 0.486 to 0.678 in Cohen's κ coefficient between consensus of two neuroradiologists and a neuroradiology fellow, and from 0.198 to 0.491 for consensus between two neuroradiologists and a senior radiology resident. ICC among three raters (expert consensus, neuroradiology fellow, and senior radiology resident), was very good when 8 HU window width and 32 HU center level setting was used. ASPECTS varied among raters. However, when using a narrowed window setting for interpretation, interobserver agreement improved.

  6. Hall A (United States)

    Federal Laboratory Consortium — The instrumentation in Hall A at the Thomas Jefferson National Accelerator Facility was designed to study electroand photo-induced reactions at very high luminosity...

  7. Hall C (United States)

    Federal Laboratory Consortium — Hall C's initial complement of equipment (shown in the figure), includes two general-purpose magnetic spectrometers. The High Momentum Spectrometer (HMS) has a large...

  8. Observation of the Zero Hall Plateau in a Quantum Anomalous Hall Insulator

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Yang; Feng, Xiao; Ou, Yunbo; Wang, Jing; Liu, Chang; Zhang, Liguo; Zhao, Dongyang; Jiang, Gaoyuan; Zhang, Shou-Cheng; He, Ke; Ma, Xucun; Xue, Qi-Kun; Wang, Yayu


    We report experimental investigations on the quantum phase transition between the two opposite Hall plateaus of a quantum anomalous Hall insulator. We observe a well-defined plateau with zero Hall conductivity over a range of magnetic field around coercivity when the magnetization reverses. The features of the zero Hall plateau are shown to be closely related to that of the quantum anomalous Hall effect, but its temperature evolution exhibits a significant difference from the network model for a conventional quantum Hall plateau transition. We propose that the chiral edge states residing at the magnetic domain boundaries, which are unique to a quantum anomalous Hall insulator, are responsible for the novel features of the zero Hall plateau.

  9. Quantum critical Hall exponents

    CERN Document Server

    Lütken, C A


    We investigate a finite size "double scaling" hypothesis using data from an experiment on a quantum Hall system with short range disorder [1-3]. For Hall bars of width w at temperature T the scaling form is w(-mu)T(-kappa), where the critical exponent mu approximate to 0.23 we extract from the data is comparable to the multi-fractal exponent alpha(0) - 2 obtained from the Chalker-Coddington (CC) model [4]. We also use the data to find the approximate location (in the resistivity plane) of seven quantum critical points, all of which closely agree with the predictions derived long ago from the modular symmetry of a toroidal sigma-model with m matter fields [5]. The value nu(8) = 2.60513 ... of the localisation exponent obtained from the m = 8 model is in excellent agreement with the best available numerical value nu(num) = 2.607 +/- 0.004 derived from the CC-model [6]. Existing experimental data appear to favour the m = 9 model, suggesting that the quantum Hall system is not in the same universality class as th...

  10. Technology in Residence. (United States)

    Fox, Jordan


    Discusses the necessity for incorporating current technology in today's college residence halls to meet the more diverse and continued activities of its students. Technology addressed covers data networking and telecommunications, heating and cooling systems, and fire-safety systems. (GR)

  11. Experimental halls workshop summary

    International Nuclear Information System (INIS)

    Thorndike, A.


    A brief discussion is given of: (1) pros and cons of open areas as compared with enclosed halls; (2) experimental hall needs of ep, anti p p, and other options; (3) hall for the lepton detector; and, (4) hall for the hadron spectrometer

  12. Comportamento alimentar em moradia estudantil: um espaço para promoção da saúde Food behavior in student residence halls: a setting for health promotion

    Directory of Open Access Journals (Sweden)

    Hayda Josiane Alves


    Full Text Available OBJETIVO: Descrever qualitativamente o comportamento alimentar de estudantes residentes em moradia universitária. MÉTODOS: Estudo quanti-qualitativo realizado com uma amostra sorteada de cem estudantes universitários, residentes em moradia estudantil no município de Campinas, SP, em 2004. Foram feitas entrevistas utilizando-se formulário para colher o recordatório alimentar nas últimas 24 horas, incluindo questões abertas relativas ao sistema de compras e práticas de consumo. Foram criados critérios para análise da qualidade das refeições. Foram utilizados os testes qui-quadrado e o exato de Fisher, ao nível de significância de 5%. Nas entrevistas foram obtidos e analisados dados de natureza representacional, com base na teoria das representações sociais de Moscivici. RESULTADOS: Avaliação do recordatório 24 horas: desjejum, 30% não consumiram, 13% foram completos, 37% padrão e 20% incompletos; almoço, 5% não consumiram, 72% consumiram refeição completa e 23% incompleta; jantar, 1% não consumiu, 36% foram completos e 63% incompletos. A refeição de melhor qualidade foi o almoço, e dos estudantes que almoçaram, 63% o fizeram no restaurante universitário. Dos entrevistados, 48% não ingeriram nenhuma fruta e 39% não ingeriram leite no dia. A maioria (69% apresentou comportamento alimentar individual e 43% consideraram que o fato de comer em companhia alterava positivamente sua alimentação. A experiência de passar a prover a própria alimentação modifica comportamentos e representações entre os estudantes acerca do ato alimentar. CONCLUSÕES: A qualidade da alimentação, os padrões de comensalidade e as representações sociais do ato alimentar oferecem subsídios para o desenvolvimento de práticas de cuidado com a alimentação e promoção à saúde.OBJECTIVE: To qualitatively describe food practices of students living in a residence hall. METHODS: A quantitative and qualitative study was carried out in a

  13. A Framework for Residence Hall Community Development. (United States)

    Davis, Alan H.; Daugherty, Michael S.

    This paper addresses the issue of improving student retention and quality of life on campus through the application of principles expressed by Sabre (1980) involving community development. Sabre's ethical principle of nurturing the capacity for mutual persuasion is discussed as a central vision and purpose for organizing and guiding community…

  14. Skyrmions and Hall viscosity


    Kim, Bom Soo


    We discuss the contribution of magnetic Skyrmions to the Hall viscosity and propose a simple way to identify it in experiments. The topological Skyrmion charge density has a distinct signature in the electric Hall conductivity that is identified in existing experimental data. In an electrically neutral system, the Skyrmion charge density is directly related to the thermal Hall conductivity. These results are direct consequences of the field theory Ward identities, which relate various physica...

  15. Quantum spin Hall phases

    International Nuclear Information System (INIS)

    Murakami, Shuichi


    We review our recent theoretical works on the quantum spin Hall effect. First we compare edge states in various 2D systems, and see whether they are robust or fragile against perturbations. Through the comparisons we see the robust nature of edge states in 2D quantum spin Hall phases. We see how it is protected by the Z 2 topological number, and reveal the nature of the Z 2 topological number by studying the phase transition between the quantum spin Hall and insulator phases. We also review our theoretical proposal of the ultrathin bismuth film as a candidate to the 2D quantum spin Hall system. (author)

  16. Healthy Dining Hall Eating (United States)

    ... Healthy Dining Hall Eating What's in this article? Good Intentions What Does Your Body Need? Choosing Carbs Choosing Veggies (and Fruit) Choosing Protein Choosing Dairy Snack Attacks Meeting Special Dietary Needs Portion Sizes Portion ...

  17. Halls Lake 1990 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Salt marsh habitats along the shoreline of Halls Lake are threatened by wave erosion, but the reconstruction of barrier islands to reduce this erosion will modify or...

  18. Spin hall effect associated with SU(2) gauge field (United States)

    Tao, Y.


    In this paper, we focus on the connection between spin Hall effect and spin force. Here we investigate that the spin force due to spin-orbit coupling, which, in two-dimensional system, is equivalent to forces of Hirsch and Chudnovsky besides constant factors 3 and frac{3}{2} respectively, is a part of classic Anandan force, and that the spin Hall effect is an anomalous Hall effect. Furthermore, we develop the method of AC phase to derive the expression for the spin force, and note that the most basic spin Hall effect indeed originate from the AC phase and is therefore an intrinsic quantum mechanical property of spin. This method differs from approach of Berry phase in the study of anomalous Hall effect , which is the intrinsic property of the perfect crystal. On the other hand, we use an elegant skill to show that the Chudnovsky-Drude model is reasonable. Here we have improved the theoretical values of spin Hall conductivity of Chudnovsky. Compared to the theoretical values of spin Hall conductivity in the Chudnovsky-Drude model, ours are in better agreement with experimentation. Finally, we discuss the relation between spin Hall effect and fractional statistics.

  19. Hall effect in hopping regime

    Energy Technology Data Exchange (ETDEWEB)

    Avdonin, A., E-mail: [Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa (Poland); Skupiński, P. [Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa (Poland); Grasza, K. [Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa (Poland); Institute of Electronic Materials Technology, ul. Wólczyńska 133, 01-919 Warszawa (Poland)


    A simple description of the Hall effect in the hopping regime of conductivity in semiconductors is presented. Expressions for the Hall coefficient and Hall mobility are derived by considering averaged equilibrium electron transport in a single triangle of localization sites in a magnetic field. Dependence of the Hall coefficient is analyzed in a wide range of temperature and magnetic field values. Our theoretical result is applied to our experimental data on temperature dependence of Hall effect and Hall mobility in ZnO. - Highlights: • Expressions for Hall coefficient and mobility for hopping conductivity are derived. • Theoretical result is compared with experimental curves measured on ZnO. • Simultaneous action of free and hopping conduction channels is considered. • Non-linearity of hopping Hall coefficient is predicted.

  20. Spin Hall noise

    NARCIS (Netherlands)

    Kamra, A.; Witek, F.P.; Meyer, S.; Huebl, H.; Geprägs, S.; Gross, R.; Bauer, G.E.W.; Goennenwein, S.T.B.


    We measure the low-frequency thermal fluctuations of pure spin current in a platinum film deposited on yttrium iron garnet via the inverse spin Hall effect (ISHE)-mediated voltage noise as a function of the angle ? between the magnetization and the transport direction. The results are consistent

  1. Anomalous Hall effect

    Czech Academy of Sciences Publication Activity Database

    Nagaosa, N.; Sinova, Jairo; Onoda, S.; MacDonald, A. H.; Ong, N. P.


    Roč. 82, č. 2 (2010), s. 1539-1592 ISSN 0034-6861 Institutional research plan: CEZ:AV0Z10100521 Keywords : anomalous Hall effect * spintronics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 51.695, year: 2010

  2. The Monty Hall Dilemma. (United States)

    Granberg, Donald; Brown, Thad A.


    Examines people's behavior in the Monty Hall Dilemma (MHD), in which a person must make two decisions to win a prize. In a series of five studies, found that people misapprehend probabilities in the MHD. Discusses the MHD's relation to illusion of control, belief perseverance, and the status quo bias. (RJM)

  3. Magnetometria por efeito Hall


    Fernández Pinto, Janeth


    Construímos um magnetômetro utilizando dois sensores Hall de GaAs (Toshiba- THS118) operando em um modo diferencial. Cada sensor tem um circuito préamplificador associado a ele e a diferencia de voltagem entre eles é amplificada com um ganho variável de 30 - 7000. Os sensores Hall têm dimensões típicas de 1,5 x 1,7 x 0,6 mm3 e foram montados separados um do outro de 0,71 mm, em uma configuração espacial planar. O magnetômetro foi testado usando tanto correntes dc (Idc) quant...

  4. Paired Hall states

    International Nuclear Information System (INIS)

    Greiter, M.


    This dissertation contains a collection of individual articles on various topics. Their significance in the corresponding field as well as connections between them are emphasized in a general and comprehensive introduction. In the first article, the author explores the consequences for macroscopic effective Lagrangians of assuming that the momentum density is proportional to the flow of conserved current. The universal corrections obtained for the macroscopic Lagrangian of a superconductor describe the London Hall effect, and provide a fully consistent derivation of it. In the second article, a heuristic principle is proposed for quantized Hall states: the existence and incompressibility of fractionally quantized Hall states is explained by an argument based on an adiabatic localization of magnetic flux, the process of trading uniform flux for an equal amount of fictitious flux attached to the particles. This principle is exactly implemented in the third article. For a certain class of model Hamiltonians, the author obtains Laughlin's Jastrow type wave functions explicitly from a filled Landau level, by smooth extrapolation in quantum statistics. The generalization of this analysis to the torus geometry shows that theorems restricting the possibilities of quantum statistics on closed surfaces are circumvented in the presence of a magnetic field. In the last article, the existence is proposed of a novel incompressible quantum liquid, a paired Hall state, at a half filled Landau level. This state arises adiabatically from free fermions in zero magnetic field, and reduces to a state previously proposed by Halperin in the limit of tightly bound pairs. It supports unusual excitations, including neutral fermions and charge e/4 anyons with statistical parameter θ = π/8

  5. Planar Hall Effect MRAM


    Bason, Y.; Klein, L.; Yau, J. -B.; Hong, X.; Hoffman, J.; Ahn, C. H.


    We suggest a new type of magnetic random access memory (MRAM) that is based on the phenomenon of the planar Hall effect (PHE) in magnetic films, and we demonstrate this idea with manganite films. The PHE-MRAM is structurally simpler than currently developed MRAM that is based on magnetoresistance tunnel junctions (MTJ), with the tunnel junction structure being replaced by a single layer film.

  6. Spin Hall effect devices

    Czech Academy of Sciences Publication Activity Database

    Jungwirth, Tomáš; Wunderlich, Joerg; Olejník, Kamil


    Roč. 11, č. 5 (2012), s. 382-390 ISSN 1476-1122 EU Projects: European Commission(XE) 268066 - 0MSPIN; European Commission(XE) 215368 - SemiSpinNet Grant - others:AV ČR(CZ) AP0801 Program:Akademická prémie - Praemium Academiae Institutional research plan: CEZ:AV0Z10100521 Keywords : spin Hall effect * spintronics * spin transistor Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 35.749, year: 2012

  7. Spin Hall effect

    Czech Academy of Sciences Publication Activity Database

    Sinova, Jairo; Valenzuela, O.V.; Wunderlich, Joerg; Back, C.H.; Jungwirth, Tomáš


    Roč. 87, č. 4 (2015), s. 1213-1259 ISSN 0034-6861 R&D Projects: GA MŠk(CZ) LM2011026; GA ČR GB14-37427G EU Projects: European Commission(XE) 268066 - 0MSPIN Institutional support: RVO:68378271 Keywords : spin Hall effect * spintronics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 33.177, year: 2015

  8. Optimal Volume for Concert Halls Based on Ando’s Subjective Preference and Barron Revised Theories

    Directory of Open Access Journals (Sweden)

    Salvador Cerdá


    Full Text Available The Ando-Beranek’s model, a linear version of Ando’s subjective preference theory, obtained by the authors in a recent work, was combined with Barron revised theory. An optimal volume region for each reverberation time was obtained for classical music in symphony orchestra concert halls. The obtained relation was tested with good agreement with the top rated halls reported by Beranek and other halls with reported anomalies.

  9. Hall effect in a strong magnetic field: Direct comparisons of compressible magnetohydrodynamics and the reduced Hall magnetohydrodynamic equations

    International Nuclear Information System (INIS)

    Martin, L. N.; Dmitruk, P.; Gomez, D. O.


    In this work we numerically test a model of Hall magnetohydrodynamics in the presence of a strong mean magnetic field: the reduced Hall magnetohydrodynamic model (RHMHD) derived by [Gomez et al., Phys. Plasmas 15, 102303 (2008)] with the addition of weak compressible effects. The main advantage of this model lies in the reduction of computational cost. Nevertheless, up until now the degree of agreement with the original Hall MHD system and the range of validity in a regime of turbulence were not established. In this work direct numerical simulations of three-dimensional Hall MHD turbulence in the presence of a strong mean magnetic field are compared with simulations of the weak compressible RHMHD model. The results show that the degree of agreement is very high (when the different assumptions of RHMHD, such as spectral anisotropy, are satisfied). Nevertheless, when the initial conditions are isotropic but the mean magnetic field is maintained strong, the results differ at the beginning but asymptotically reach a good agreement at relatively short times. We also found evidence that the compressibility still plays a role in the dynamics of these systems, and the weak compressible RHMHD model is able to capture these effects. In conclusion the weak compressible RHMHD model is a valid approximation of the Hall MHD turbulence in the relevant physical context.

  10. Quantum hall effect. A perspective

    International Nuclear Information System (INIS)

    Aoki, Hideo


    Novel concepts and phenomena are emerging recently in the physics of quantum Hall effect. This article gives an overview, which starts from the fractional quantum Hall system viewed as an extremely strongly correlated system, and move on to present various phenomena involving internal degrees of freedom (spin and layer), non-equilibrium and optical properties, and finally the spinoff to anomalous Hall effect and the rotating Bose-Einstein condensate. (author)

  11. Magnesium Hall Thruster (United States)

    Szabo, James J.


    This Phase II project is developing a magnesium (Mg) Hall effect thruster system that would open the door for in situ resource utilization (ISRU)-based solar system exploration. Magnesium is light and easy to ionize. For a Mars- Earth transfer, the propellant mass savings with respect to a xenon Hall effect thruster (HET) system are enormous. Magnesium also can be combusted in a rocket with carbon dioxide (CO2) or water (H2O), enabling a multimode propulsion system with propellant sharing and ISRU. In the near term, CO2 and H2O would be collected in situ on Mars or the moon. In the far term, Mg itself would be collected from Martian and lunar regolith. In Phase I, an integrated, medium-power (1- to 3-kW) Mg HET system was developed and tested. Controlled, steady operation at constant voltage and power was demonstrated. Preliminary measurements indicate a specific impulse (Isp) greater than 4,000 s was achieved at a discharge potential of 400 V. The feasibility of delivering fluidized Mg powder to a medium- or high-power thruster also was demonstrated. Phase II of the project evaluated the performance of an integrated, highpower Mg Hall thruster system in a relevant space environment. Researchers improved the medium power thruster system and characterized it in detail. Researchers also designed and built a high-power (8- to 20-kW) Mg HET. A fluidized powder feed system supporting the high-power thruster was built and delivered to Busek Company, Inc.

  12. Spin Hall effect transistor

    Czech Academy of Sciences Publication Activity Database

    Wunderlich, Joerg; Park, B.G.; Irvine, A.C.; Zarbo, Liviu; Rozkotová, E.; Němec, P.; Novák, Vít; Sinova, Jairo; Jungwirth, Tomáš


    Roč. 330, č. 6012 (2010), s. 1801-1804 ISSN 0036-8075 R&D Projects: GA AV ČR KAN400100652; GA MŠk LC510 EU Projects: European Commission(XE) 215368 - SemiSpinNet Grant - others:AV ČR(CZ) AP0801 Program:Akademická prémie - Praemium Academiae Institutional research plan: CEZ:AV0Z10100521 Keywords : spin Hall effect * spintronics * spin transistor Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 31.364, year: 2010

  13. The ISOLDE hall

    CERN Multimedia

    Maximilien Brice


    Since 1992, after its move from the 600 MeV SC, ISOLDE is a customer of the Booster (then 1 GeV, now 1.4 GeV). The intense Booster beam (some 3E13 protons per pulse) is directed onto a target, from which a mixture of isotopes emanates. After ionization and electrostatic acceleration to 60 keV, they enter one of the 2 spectrometers (General Purpose Separator: GPS, and High Resolution Separator: HRS) from which the selected ions are directed to the experiments. The photos show: the REX-ISOLDE post accelerator; the mini-ball experiment; an overview of the ISOLDE hall. In the picture (_12) of the hall, the separators are behind the wall. From either of them, beams can be directed into any of the many beamlines towards the experiments, some of which are visible in the foreground. The elevated cubicle at the left is EBIS (Electron Beam Ion Source), which acts as a charge-state multiplier for the REX facility. The ions are further mass analzyzed and passed on to the linac which accelerates them to higher energies. T...

  14. Farm Hall: The Play (United States)

    Cassidy, David C.


    It's July 1945. Germany is in defeat and the atomic bombs are on their way to Japan. Under the direction of Samuel Goudsmit, the Allies are holding some of the top German nuclear scientists-among them Heisenberg, Hahn, and Gerlach-captive in Farm Hall, an English country manor near Cambridge, England. As secret microphones record their conversations, the scientists are unaware of why they are being held or for how long. Thinking themselves far ahead of the Allies, how will they react to the news of the atomic bombs? How will these famous scientists explain to themselves and to the world their failure to achieve even a chain reaction? How will they come to terms with the horror of the Third Reich, their work for such a regime, and their behavior during that period? This one-act play is based upon the transcripts of their conversations as well as the author's historical work on the subject.

  15. Resistive and Hall weighting functions in three dimensions (United States)

    Koon, D. W.; Knickerbocker, C. J.


    The authors extend their study of the effect of macroscopic impurities on resistive and Hall measurements to include objects of finite thickness. The effect of such impurities is calculated for a series of rectangular parallelepipeds with two current and two voltage contacts on the corners of one square face. The weighting functions display singularities near these contacts, but these are shown to vanish in the two-dimensional limit, in agreement with previous results. Finally, it is shown that while Hall measurements principally sample the plane of the electrodes, resistivity measurements sample more of the interior of an object of finite thickness.

  16. Theory of spin Hall effect: extension of the Drude model. (United States)

    Chudnovsky, Eugene M


    An extension of the Drude model is proposed that accounts for the spin and spin-orbit interaction of charge carriers. Spin currents appear due to the combined action of the external electric field, crystal field, and scattering of charge carriers. The expression for the spin Hall conductivity is derived for metals and semiconductors that is independent of the scattering mechanism. In cubic metals, the spin Hall conductivity sigma s and charge conductivity sigma c are related through sigma s=[2pi variant /(3mc2)]sigma2c with m being the bare electron mass. The theoretically computed value is in agreement with experiment.

  17. Hall Effect Gyrators and Circulators (United States)

    Viola, Giovanni; DiVincenzo, David P.


    The electronic circulator and its close relative the gyrator are invaluable tools for noise management and signal routing in the current generation of low-temperature microwave systems for the implementation of new quantum technologies. The current implementation of these devices using the Faraday effect is satisfactory but requires a bulky structure whose physical dimension is close to the microwave wavelength employed. The Hall effect is an alternative nonreciprocal effect that can also be used to produce desired device functionality. We review earlier efforts to use an Ohmically contacted four-terminal Hall bar, explaining why this approach leads to unacceptably high device loss. We find that capacitive coupling to such a Hall conductor has much greater promise for achieving good circulator and gyrator functionality. We formulate a classical Ohm-Hall analysis for calculating the properties of such a device, and show how this classical theory simplifies remarkably in the limiting case of the Hall angle approaching 90°. In this limit, we find that either a four-terminal or a three-terminal capacitive device can give excellent circulator behavior, with device dimensions far smaller than the ac wavelength. An experiment is proposed to achieve GHz-band gyration in millimeter (and smaller) scale structures employing either semiconductor heterostructure or graphene Hall conductors. An inductively coupled scheme for realizing a Hall gyrator is also analyzed.

  18. Hall Effect Gyrators and Circulators

    Directory of Open Access Journals (Sweden)

    Giovanni Viola


    Full Text Available The electronic circulator and its close relative the gyrator are invaluable tools for noise management and signal routing in the current generation of low-temperature microwave systems for the implementation of new quantum technologies. The current implementation of these devices using the Faraday effect is satisfactory but requires a bulky structure whose physical dimension is close to the microwave wavelength employed. The Hall effect is an alternative nonreciprocal effect that can also be used to produce desired device functionality. We review earlier efforts to use an Ohmically contacted four-terminal Hall bar, explaining why this approach leads to unacceptably high device loss. We find that capacitive coupling to such a Hall conductor has much greater promise for achieving good circulator and gyrator functionality. We formulate a classical Ohm-Hall analysis for calculating the properties of such a device, and show how this classical theory simplifies remarkably in the limiting case of the Hall angle approaching 90°. In this limit, we find that either a four-terminal or a three-terminal capacitive device can give excellent circulator behavior, with device dimensions far smaller than the ac wavelength. An experiment is proposed to achieve GHz-band gyration in millimeter (and smaller scale structures employing either semiconductor heterostructure or graphene Hall conductors. An inductively coupled scheme for realizing a Hall gyrator is also analyzed.

  19. Topological Hall and spin Hall effects in disordered skyrmionic textures

    KAUST Repository

    Ndiaye, Papa Birame


    We carry out a thorough study of the topological Hall and topological spin Hall effects in disordered skyrmionic systems: the dimensionless (spin) Hall angles are evaluated across the energy-band structure in the multiprobe Landauer-Büttiker formalism and their link to the effective magnetic field emerging from the real-space topology of the spin texture is highlighted. We discuss these results for an optimal skyrmion size and for various sizes of the sample and find that the adiabatic approximation still holds for large skyrmions as well as for nanoskyrmions. Finally, we test the robustness of the topological signals against disorder strength and show that the topological Hall effect is highly sensitive to momentum scattering.

  20. City and Town Halls; townHalls13 (United States)

    University of Rhode Island Geospatial Extension Program — Locations of city and town halls in Rhode Island. Derived using information originally compiled by the State of Rhode Island (, and built upon...

  1. Hamaoka Atomic Energy Hall, Chubu Electric Power Co., Inc

    International Nuclear Information System (INIS)

    Kawasaki, Yukio


    Hamaoka Nuclear Power Station was constructed in the very large site of about 1.6 million m 2 surrounded by sand dunes and pine forests at the southern tip of Shizuoka Prefecture. Hamaoka Atomic Energy Hall was built on the right side of this power station. This hall had been planned as a part of the works commemorating the 20th anniversary of the founding of the company, and was opened in August, 1972. The building is of steel frame type, and has two floors of 1135 m 2 total area. The first floor comprises cinema room, power generation corner and open gallery, and the second floor comprises meeting room, native land corner and observation room. Moreover, there is observation platform on the roof. The purpose of the hall is coexistence and coprosperity with the regional residents, and 13 persons make explanations to visitors having reached to 1.9 million as of the end of June, 1979. It is incorporated in the sightseeing route centering around the Omaezaki lighthouse. The cinema hall accommodates 120 men, and the films concerning nuclear power generation and the construction of a nuclear power plant are shown. In the power generation corner, the explanation on nuclear power generation is made with models and panels. The third hall is being built now as energy corner, and it will be completed in autumn, 1979. (Kako, I.)

  2. Anomalous Hall effect (United States)

    Nagaosa, Naoto; Sinova, Jairo; Onoda, Shigeki; MacDonald, A. H.; Ong, N. P.


    The anomalous Hall effect (AHE) occurs in solids with broken time-reversal symmetry, typically in a ferromagnetic phase, as a consequence of spin-orbit coupling. Experimental and theoretical studies of the AHE are reviewed, focusing on recent developments that have provided a more complete framework for understanding this subtle phenomenon and have, in many instances, replaced controversy by clarity. Synergy between experimental and theoretical works, both playing a crucial role, has been at the heart of these advances. On the theoretical front, the adoption of the Berry-phase concepts has established a link between the AHE and the topological nature of the Hall currents. On the experimental front, new experimental studies of the AHE in transition metals, transition-metal oxides, spinels, pyrochlores, and metallic dilute magnetic semiconductors have established systematic trends. These two developments, in concert with first-principles electronic structure calculations, strongly favor the dominance of an intrinsic Berry-phase-related AHE mechanism in metallic ferromagnets with moderate conductivity. The intrinsic AHE can be expressed in terms of the Berry-phase curvatures and it is therefore an intrinsic quantum-mechanical property of a perfect crystal. An extrinsic mechanism, skew scattering from disorder, tends to dominate the AHE in highly conductive ferromagnets. The full modern semiclassical treatment of the AHE is reviewed which incorporates an anomalous contribution to wave-packet group velocity due to momentum-space Berry curvatures and correctly combines the roles of intrinsic and extrinsic (skew-scattering and side-jump) scattering-related mechanisms. In addition, more rigorous quantum-mechanical treatments based on the Kubo and Keldysh formalisms are reviewed, taking into account multiband effects, and demonstrate the equivalence of all three linear response theories in the metallic regime. Building on results from recent experiment and theory, a

  3. Bilateral agreements

    International Nuclear Information System (INIS)


    Ten bilateral agreements are presented. These are: 1) Co-operation agreement relating to the peaceful uses of nuclear energy between Argentina and EURATOM (1996); 2) Agreement on co-operation in the peaceful uses of nuclear energy between Argentina and Greece (1997); 3) Implementing arrangement for technical exchange and co-operation in the area of peaceful uses of nuclear energy between Argentina and the United States (1997); 4) Agreement concerning co-operation in nuclear science and technology between Australia and Indonesia (1997); 5) Implementation of the 1985 Agreement for co-operation concerning the peaceful uses of nuclear energy between the People's Republic of China and the United States (1998); 6) Protocol of co-operation between France and Lithuania (1997); 7) Agreement on co-operation in energy research, science and technology, and development between Germany and the United States (1998); 8) Agreement on early notification of a nuclear accident and exchange of information on nuclear facilities between Greece and Romania (1997); 9) Agreement on early notification of nuclear accidents and co-operation in the field of nuclear safety between Hungary and the Ukraine (1997); 10) Agreement in the field of radioactive waste management between Switzerland and the United States (1997). (K.A.)

  4. Modular invariance, universality and crossover in the quantum Hall effect

    International Nuclear Information System (INIS)

    Dolan, Brian P.


    An analytic form for the conductivity tensor in crossover between two quantum Hall plateaux is derived, which appears to be in good agreement with existing experimental data. The derivation relies on an assumed symmetry between quantum Hall states, a generalisation of the law of corresponding states from rational filling factors to complex conductivity, which has a mathematical expression in terms of an action of the modular group on the upper-half complex conductivity plane. This symmetry implies universality in quantum Hall crossovers. The assumption that the β-function for the complex conductivity is a complex analytic function, together with some experimental constraints, results in an analytic expression for the crossover, as a function of the external magnetic field

  5. Gauge invariance and fractional quantized Hall effect

    International Nuclear Information System (INIS)

    Tao, R.; Wu, Y.S.


    It is shown that gauge invariance arguments imply the possibility of fractional quantized Hall effect; the Hall conductance is accurately quantized to a rational value. The ground state of a system showing the fractional quantized Hall effect must be degenerate; the non-degenerate ground state can only produce the integral quantized Hall effect. 12 references

  6. Structural Analysis of the Resident Assistant Cultural Diversity Questionnaire (United States)

    Johnson, Vanessa D.; Kang, Young-Shin; Thompson, George F.


    This study investigated the five-factor structure of the Resident Assistant Cultural Diversity (RACD) instrument, which assesses resident assistant (RA) confidence in addressing issues of cultural diversity in college and university residence halls. The instrument has five components that explore RA confidence: (1) belief in the need for cultural…

  7. A game generalizing Hall's theorem


    Rabern, Landon


    We characterize the initial positions from which the first player has a winning strategy in a certain two-player game. This provides a generalization of Hall's theorem. Vizing's edge coloring theorem follows from a special case.

  8. Shared Magnetics Hall Thruster Project (United States)

    National Aeronautics and Space Administration — In the proposed Phase II program, Busek Co. will demonstrate an innovative methodology for clustering Hall thrusters into a high performance, very high power...

  9. Shared Magnetics Hall Thruster Project (United States)

    National Aeronautics and Space Administration — In the proposed Phase I program, Busek Co. will demonstrate an innovative methodology for clustering Hall thrusters into a high performance, very high power...

  10. "Hall mees" Linnateatris / Triin Sinissaar

    Index Scriptorium Estoniae

    Sinissaar, Triin


    Tallinn Linnateatri ja Raadioteatri ühislavastus "Hall mees" Gill Adamsi näidendi järgi, lavastaja Eero Spriit, osades Helene Vannari ja Väino Laes, kunstnik Kustav - Agu Püüman. Esietendus 22. okt

  11. Sheldon-Hall syndrome

    Directory of Open Access Journals (Sweden)

    Bamshad Michael J


    Full Text Available Abstract Sheldon-Hall syndrome (SHS is a rare multiple congenital contracture syndrome characterized by contractures of the distal joints of the limbs, triangular face, downslanting palpebral fissures, small mouth, and high arched palate. Epidemiological data for the prevalence of SHS are not available, but less than 100 cases have been reported in the literature. Other common clinical features of SHS include prominent nasolabial folds, high arched palate, attached earlobes, mild cervical webbing, short stature, severe camptodactyly, ulnar deviation, and vertical talus and/or talipes equinovarus. Typically, the contractures are most severe at birth and non-progressive. SHS is inherited in an autosomal dominant pattern but about half the cases are sporadic. Mutations in either MYH3, TNNI2, or TNNT3 have been found in about 50% of cases. These genes encode proteins of the contractile apparatus of fast twitch skeletal muscle fibers. The diagnosis of SHS is based on clinical criteria. Mutation analysis is useful to distinguish SHS from arthrogryposis syndromes with similar features (e.g. distal arthrogryposis 1 and Freeman-Sheldon syndrome. Prenatal diagnosis by ultrasonography is feasible at 18–24 weeks of gestation. If the family history is positive and the mutation is known in the family, prenatal molecular genetic diagnosis is possible. There is no specific therapy for SHS. However, patients benefit from early intervention with occupational and physical therapy, serial casting, and/or surgery. Life expectancy and cognitive abilities are normal.

  12. Experimental Studies of Anode Sheath Phenomena in a Hall Thruster Discharge

    International Nuclear Information System (INIS)

    Dorf, L.; Raitses, Y.; Fisch, N.J.


    Both electron-repelling and electron-attracting anode sheaths in a Hall thruster were characterized by measuring the plasma potential with biased and emissive probes [L. Dorf, Y. Raitses, V. Semenov, and N.J. Fisch, Appl. Phys. Let. 84 (2004) 1070]. In the present work, two-dimensional structures of the plasma potential, electron temperature, and plasma density in the near-anode region of a Hall thruster with clean and dielectrically coated anodes are identified. Possible mechanisms of anode sheath formation in a Hall thruster are analyzed. The path for current closure to the anode appears to be the determining factor in the anode sheath formation process. The main conclusion of this work is that the anode sheath formation in Hall thrusters differs essentially from that in the other gas discharge devices, like a glow discharge or a hollow anode, because the Hall thruster utilizes long electron residence times to ionize rather than high neutral pressures

  13. Theory of spin Hall effect


    Chudnovsky, Eugene M.


    An extension of Drude model is proposed that accounts for spin and spin-orbit interaction of charge carriers. Spin currents appear due to combined action of the external electric field, crystal field and scattering of charge carriers. The expression for spin Hall conductivity is derived for metals and semiconductors that is independent of the scattering mechanism. In cubic metals, spin Hall conductivity $\\sigma_s$ and charge conductivity $\\sigma_c$ are related through $\\sigma_s = [2 \\pi \\hbar...

  14. Transport Signatures of the Hall Viscosity. (United States)

    Delacrétaz, Luca V; Gromov, Andrey


    Hall viscosity is a nondissipative response function describing momentum transport in two-dimensional systems with broken parity. It is quantized in the quantum Hall regime, and contains information about the topological order of the quantum Hall state. Hall viscosity can distinguish different quantum Hall states with identical Hall conductances, but different topological order. To date, an experimentally accessible signature of Hall viscosity is lacking. We exploit the fact that Hall viscosity contributes to charge transport at finite wavelengths, and can therefore be extracted from nonlocal resistance measurements in inhomogeneous charge flows. We explain how to determine the Hall viscosity from such a transport experiment. In particular, we show that the profile of the electrochemical potential close to contacts where current is injected is sensitive to the value of the Hall viscosity.

  15. Not your grandfather's concert hall (United States)

    Cooper, Russell; Malenka, Richard; Griffith, Charles; Friedlander, Steven


    The opening of Judy and Arthur Zankel Hall on 12 September 2003, restores Andrew Carnegie's original 1891 concept of having three outstanding auditoriums of different sizes under one roof, and creates a 21st-century venue for music performance and education. With concerts ranging from early music to avant-garde multimedia productions, from jazz to world music, and from solo recitals to chamber music, Zankel Hall expands the breadth and depth of Carnegie Hall's offerings. It allows for the integration of programming across three halls with minifestivals tailored both to the size and strengths of each hall and to the artists and music to be performed. The new flexible space also provides Carnegie Hall with an education center equipped with advanced communications technology. This paper discusses the unique program planned for this facility and how the architects, theatre consultants, and acousticians developed a design that fulfilled the client's expectations and coordinated the construction of the facility under the floor of the main Isaac Stern Auditorium without having to cancel a single performance.

  16. Investigations of Probe Induced Perturbations in a Hall Thruster

    International Nuclear Information System (INIS)

    D. Staack; Y. Raitses; N.J. Fisch


    An electrostatic probe used to measure spatial plasma parameters in a Hall thruster generates perturbations of the plasma. These perturbations are examined by varying the probe material, penetration distance, residence time, and the nominal thruster conditions. The study leads us to recommendations for probe design and thruster operating conditions to reduce discharge perturbations, including metal shielding of the probe insulator and operation of the thruster at lower densities

  17. Iodine Hall Thruster (United States)

    Szabo, James


    Iodine enables dramatic mass and cost savings for lunar and Mars cargo missions, including Earth escape and near-Earth space maneuvers. The demonstrated throttling ability of iodine is important for a singular thruster that might be called upon to propel a spacecraft from Earth to Mars or Venus. The ability to throttle efficiently is even more important for missions beyond Mars. In the Phase I project, Busek Company, Inc., tested an existing Hall thruster, the BHT-8000, on iodine propellant. The thruster was fed by a high-flow iodine feed system and supported by an existing Busek hollow cathode flowing xenon gas. The Phase I propellant feed system was evolved from a previously demonstrated laboratory feed system. Throttling of the thruster between 2 and 11 kW at 200 to 600 V was demonstrated. Testing showed that the efficiency of iodine fueled BHT-8000 is the same as with xenon, with iodine delivering a slightly higher thrust-to-power (T/P) ratio. In Phase II, a complete iodine-fueled system was developed, including the thruster, hollow cathode, and iodine propellant feed system. The nominal power of the Phase II system is 8 kW; however, it can be deeply throttled as well as clustered to much higher power levels. The technology also can be scaled to greater than 100 kW per thruster to support megawatt-class missions. The target thruster efficiency for the full-scale system is 65 percent at high specific impulse (Isp) (approximately 3,000 s) and 60 percent at high thrust (Isp approximately 2,000 s).

  18. Bilateral agreements

    International Nuclear Information System (INIS)



    The bilateral agreements concern Brazil with United States relative to the co operation in nuclear energy, Germany with Russian Federation relative to the elimination and disposal of nuclear weapons; The multilateral agreements concerns the signature of the Protocols to amend the Paris and Brussels Conventions, the multilateral nuclear environmental programme in the Russian Federation, the status of Conventions in the field of nuclear energy. (N.C.)

  19. Avalanche breakdown of the quantum hall effects

    CERN Document Server

    Komiyama, S


    Heat stability of two-dimensional electron gas (2DEG) systems in the integer quantum hall effect (IQHE) regime is discussed, and a heat instability is suggested to be the intrinsic mechanism behind the breakdown of the IQHE. Phenomenological argument is provided to suggest that the 2DEG system in the IQHE state becomes thermally unstable when the Hall electric field E sub y reaches a threshold value E sub b. Above E sub b , excited nonequilibrium electrons (holes), which are initially present in the conductor as the temperature fluctuation, are accelerated by E sub y and the 2DEG thereby undergoes a transition to a warm dissipative state. The critical field, E sub b , of this abrupt transition is theoretically estimated and shown to be in fare agreement with experimentally reported values. Consideration of the dynamics of electrons suggests that the transition is a process of avalanche electron-hole pair multiplication, in which a small number of non-equilibrium carriers, gains kinetic energy within a Landau ...

  20. ac spin-Hall effect

    International Nuclear Information System (INIS)

    Entin-Wohlman, O.


    Full Text:The spin-Hall effect is described. The Rashba and Dresselhaus spin-orbit interactions are both shown to yield the low temperature spin-Hall effect for strongly localized electrons coupled to phonons. A frequency-dependent electric field E(ω) generates a spin-polarization current, normal to E, due to interference of hopping paths. At zero temperature the corresponding spin-Hall conductivity is real and is proportional to ω 2 . At non-zero temperatures the coupling to the phonons yields an imaginary term proportional to ω. The interference also yields persistent spin currents at thermal equilibrium, at E = 0. The contributions from the Dresselhaus and Rashba interactions to the interference oppose each other

  1. Novel concepts in Hall sensors (United States)

    Mani, R. G.


    Hall effect devices are widely used as position sensors and contactless switches in applications ranging from electric motors to soft drink machines and automobiles. Such devices typically operate in an adverse environment where offset voltages originating from various physical effects limit the effective sensitivity of the sensor to the weak magnetic field (B device that automatically reduces such spurious offsets is desirable because improved 'signal to offset' would relax manufacturing tolerances and other constraints within the sensor system. Here, we examine some techniques and sensor configurations (R. G. Mani, K. von Klitzing, F. Jost, K. Marx, S. Lindenkreuz, and H. P. Trah, Appl. Phys. Lett. 67, 2223, 1995.) based on the so called 'anti Hall bar' geometry that promise the possibility of a Silicon based Hall sensor with a field equivalent offset well below 1 mT.

  2. Role Conflict and Role Ambiguity of Resident Assistants when Confronted with Alcohol Consumption of Undergraduate Students (United States)

    Horvath, Mary Beth


    Resident assistants serve a vital function within the residence hall; however, the challenges they confront are different from those of other students. For example, resident assistants may deal with over-consumption or illegal consumption of alcohol on campus. Addressing this issue may cause resident assistants to experience role conflict and role…

  3. Complementizer Agreement

    NARCIS (Netherlands)

    van Koppen, J.M.


    Complementizers agree in phi-features with the embedded subject in dialects of German and Dutch, in Tense with the embedded clause in Irish and in phi-features with the matrix subject in certain African languages. These complementizer agreement phenomena will be the main empirical focus of this

  4. Computational Modeling of Hall Thruster Erosion (United States)

    National Aeronautics and Space Administration — Hall thrusters are being developed by NASA, DOD, and industry to meet a variety of on-board space propulsion needs. Hall thrusters have been operated successfully...

  5. ATLAS Assembly Hall Open Day

    CERN Multimedia

    Patrice Loiez


    To mark the 50th Anniversary of the founding of CERN, a day of tours, displays and presentations was held in October 2004. The assembly halls for the experiments that were waiting to be installed on the LHC, such as ATLAS shown here, were transformed into display areas and cafés.

  6. The Other Hall Effect: College Board Physics (United States)

    Sheppard, Keith; Gunning, Amanda M.


    Edwin Herbert Hall (1855-1938), discoverer of the Hall effect, was one of the first winners of the AAPT Oersted Medal for his contributions to the teaching of physics. While Hall's role in establishing laboratory work in high schools is widely acknowledged, his position as chair of the physics section of the Committee on College Entrance…

  7. Can ensemble condition in a hall be improved and measured?

    DEFF Research Database (Denmark)

    Gade, Anders Christian


    of the ceiling reflectors; and (c) changing the position of the orchestra on the platform. These variables were then tested in full scale experiments in the hall including subjective evaluation by the orchestra in order to verify their effects under practical conditions. New objective parameters, which showed......In collaboration with the Danish Broadcasting Corporation an extensive series of experiments has been carried out in The Danish Radio Concert Hall with the practical purpose of trying to improve the ensemble conditions on the platform for the resident symphony orchestra. First, a series...... of experiments in a 1:20 scale model indicated that among several suggested means the following would be the most effective and acceptable: (a) changing the shape of the sidewalls in the platform area in order to make them reflect sound back to the musicians more effectively; (b) lowering and redesigning...

  8. The Resident Assistant as Responder to the Seventies. (United States)

    Schell, Robert E.

    The nature of a residence hall program depends more on the values and behavior of the resident assistants than on the principles and structure of the system. To develop a program consistent with the most salient aspects of student development, it is important to select appropriate personnel. Any selection process is based on two assumptions: (1)…

  9. Men's Identity Development: Issues and Implications for Residence Life (United States)

    Scott, David A.; Livingston, Wade G.; Havice, Pamela A.; Cawthon, Tony W.


    Young men struggle with privilege and oppression in college and university residence halls just as they do in other educational and social contexts. While discussions and research about adolescent and adult identity development continue, little attention has focused on how a male student's identity development can impact residence life cultures on…

  10. Scanning vector Hall probe microscope

    Czech Academy of Sciences Publication Activity Database

    Fedor, J.; Cambel, V.; Gregušová, D.; Hanzelka, Pavel; Dérer, J.; Volko, J.


    Roč. 74, č. 12 (2003), s. 5105 - 5110 ISSN 0034-6748 Institutional research plan: CEZ:AV0Z2065902 Keywords : VHPM * Hall sensor * Helium cryostat Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 1.343, year: 2003 http://web. ebscohost .com/ehost/pdf?vid=8&hid=115&sid=a7c0555a-21f4-4932-b1c6-a308ac4dd50b%40sessionmgr2

  11. Quantum Hall effect in ac driven graphene: From the half-integer to the integer case (United States)

    Ding, Kai-He; Lim, Lih-King; Su, Gang; Weng, Zheng-Yu


    We theoretically study the quantum Hall effect (QHE) in graphene with an ac electric field. Based on the tight-binding model, the structure of the half-integer Hall plateaus at σxy=±(n +1 /2 ) 4 e2/h (n is an integer) gets qualitatively changed with the addition of new integer Hall plateaus at σxy=±n (4 e2/h ) starting from the edges of the band center regime towards the band center with an increasing ac field. Beyond a critical field strength, a Hall plateau with σxy=0 can be realized at the band center, hence fully restoring a conventional integer QHE with particle-hole symmetry. Within a low-energy Hamiltonian for Dirac cones merging, we show a very good agreement with the tight-binding calculations for the Hall plateau transitions. We also obtain the band structure for driven graphene ribbons to provide a further understanding on the appearance of the new Hall plateaus, showing a trivial insulator behavior for the σxy=0 state. In the presence of disorder, we numerically study the disorder-induced destruction of the quantum Hall states in a finite driven sample and find that qualitative features known in the undriven disordered case are maintained.

  12. Resident resistance. (United States)

    Price, J L; Cleary, B


    Clearly, faculty must work hard with residents to explore the nature of their resistance to a program's learning and growth opportunities. Initial steps to a deeper, more effective, and longer-lasting change process must be pursued. If resident resistance is mishandled or misunderstood, then learning and professional growth may be sidetracked and the purposes of residency training defeated. Listening to the whole person of the resident and avoiding the trap of getting caught up in merely responding to select resident behaviors that irritate us is critical. Every faculty member in the family practice residency program must recognize resistance as a form of defense that cannot immediately be torn down or taken away. Resident defenses have important purposes to play in stress reduction even if they are not always healthy. Residents, especially interns, use resistance to avoid a deeper and more truthful look at themselves as physicians. A family practice residency program that sees whole persons in their residents and that respects resident defenses will effectively manage the stress and disharmony inherent to the resistant resident.

  13. Tearing mode dynamics and sawtooth oscillation in Hall-MHD (United States)

    Ma, Zhiwei; Zhang, Wei; Wang, Sheng


    Tearing mode instability is one of the most important dynamic processes in space and laboratory plasmas. Hall effects, resulted from the decoupling of electron and ion motions, could cause the fast development and perturbation structure rotation of the tearing mode and become non-negligible. We independently developed high accuracy nonlinear MHD code (CLT) to study Hall effects on the dynamic evolution of tearing modes with Tokamak geometries. It is found that the rotation frequency of the mode in the electron diamagnetic direction is in a good agreement with analytical prediction. The linear growth rate increases with increase of the ion inertial length, which is contradictory to analytical solution in the slab geometry. We further find that the self-consistently generated rotation largely alters the dynamic behavior of the double tearing mode and the sawtooth oscillation. National Magnetic Confinement Fusion Science Program of China under Grant No. 2013GB104004 and 2013GB111004.

  14. An Audit of the Egress System in Multi-Storey Annexes of Four Halls ...

    African Journals Online (AJOL)

    A principal consideration in this case is the provision of an effective egress system that could be located at appropriate places to aid people to safety. The absence of these measures in multi-storey blocks leaves occupants at greater risk. This paper presents results of a study carried out in students' Halls of Residence at the ...

  15. Tunneling Anomalous and Spin Hall Effects. (United States)

    Matos-Abiague, A; Fabian, J


    We predict, theoretically, the existence of the anomalous Hall effect when a tunneling current flows through a tunnel junction in which only one of the electrodes is magnetic. The interfacial spin-orbit coupling present in the barrier region induces a spin-dependent momentum filtering in the directions perpendicular to the tunneling current, resulting in a skew tunneling even in the absence of impurities. This produces an anomalous Hall conductance and spin Hall currents in the nonmagnetic electrode when a bias voltage is applied across the tunneling heterojunction. If the barrier is composed of a noncentrosymmetric material, the anomalous Hall conductance and spin Hall currents become anisotropic with respect to both the magnetization and crystallographic directions, allowing us to separate this interfacial phenomenon from the bulk anomalous and spin Hall contributions. The proposed effect should be useful for proving and quantifying the interfacial spin-orbit fields in metallic and metal-semiconductor systems.

  16. Spin Hall effect by surface roughness

    KAUST Repository

    Zhou, Lingjun


    The spin Hall and its inverse effects, driven by the spin orbit interaction, provide an interconversion mechanism between spin and charge currents. Since the spin Hall effect generates and manipulates spin current electrically, to achieve a large effect is becoming an important topic in both academia and industries. So far, materials with heavy elements carrying a strong spin orbit interaction, provide the only option. We propose here a new mechanism, using the surface roughness in ultrathin films, to enhance the spin Hall effect without heavy elements. Our analysis based on Cu and Al thin films suggests that surface roughness is capable of driving a spin Hall angle that is comparable to that in bulk Au. We also demonstrate that the spin Hall effect induced by surface roughness subscribes only to the side-jump contribution but not the skew scattering. The paradigm proposed in this paper provides the second, not if only, alternative to generate a sizable spin Hall effect.

  17. Planar Hall effect bridge magnetic field sensors

    DEFF Research Database (Denmark)

    Henriksen, A.D.; Dalslet, Bjarke Thomas; Skieller, D.H.


    Until now, the planar Hall effect has been studied in samples with cross-shaped Hall geometry. We demonstrate theoretically and experimentally that the planar Hall effect can be observed for an exchange-biased ferromagnetic material in a Wheatstone bridge topology and that the sensor signal can...... be significantly enhanced by a geometric factor. For the samples in the present study, we demonstrate an enhancement of the sensor output by a factor of about 100 compared to cross-shaped sensors. The presented construction opens a new design and application area of the planar Hall effect, which we term planar...

  18. Listening to the acoustics in concert halls (United States)

    Beranek, Leo L.; Griesinger, David


    How does acoustics affect the symphonic music performed in a concert hall? The lecture begins with an illustrated discussion of the architectural features that influence the acoustics. Boston Symphony Hall, which was built in 1900 when only one facet of architectural design was known, now rates as one of the world's great halls. How this occurred will be presented. Music is composed with some acoustical environment in mind and this varies with time from the Baroque to the Romantic to the Modern musical period. Conductors vary their interpretation according to the hall they are in. Well-traveled listeners and music critics have favorite halls. The lecture then presents a list of 58 halls rank ordered according to their acoustical quality based on interviews of music critics and conductors. Modern acoustical measurements made in these halls are compared with their rankings. Music recordings will be presented that demonstrate how halls sound that have different measured acoustical parameters. Photographs of a number of recently built halls are shown as examples of how these known acoustical factors have been incorporated into architectural design.

  19. Anomalous Hall effect in polycrystalline Ni films

    KAUST Repository

    Guo, Zaibing


    We systematically studied the anomalous Hall effect in a series of polycrystalline Ni films with thickness ranging from 4 to 200 nm. It is found that both the longitudinal and anomalous Hall resistivity increased greatly as film thickness decreased. This enhancement should be related to the surface scattering. In the ultrathin films (46 nm thick), weak localization corrections to anomalous Hall conductivity were studied. The granular model, taking into account the dominated intergranular tunneling, has been employed to explain this phenomenon, which can explain the weak dependence of anomalous Hall resistivity on longitudinal resistivity as well. © 2011 Elsevier Ltd. All rights reserved.

  20. Hall-effect arc protector (United States)

    Rankin, R.A.; Kotter, D.K.


    The Hall-Effect Arc Protector is used to protect sensitive electronics from high energy arcs. The apparatus detects arcs by monitoring an electrical conductor, of the instrument, for changes in the electromagnetic field surrounding the conductor which would be indicative of a possible arcing condition. When the magnitude of the monitored electromagnetic field exceeds a predetermined threshold, the potential for an instrument damaging are exists and the control system logic activates a high speed circuit breaker. The activation of the breaker shunts the energy imparted to the input signal through a dummy load to the ground. After the arc condition is terminated, the normal signal path is restored. 2 figs.

  1. Temperature Gradient in Hall Thrusters

    International Nuclear Information System (INIS)

    Staack, D.; Raitses, Y.; Fisch, N.J.


    Plasma potentials and electron temperatures were deduced from emissive and cold floating probe measurements in a 2 kW Hall thruster, operated in the discharge voltage range of 200-400 V. An almost linear dependence of the electron temperature on the plasma potential was observed in the acceleration region of the thruster both inside and outside the thruster. This result calls into question whether secondary electron emission from the ceramic channel walls plays a significant role in electron energy balance. The proportionality factor between the axial electron temperature gradient and the electric field is significantly smaller than might be expected by models employing Ohmic heating of electrons

  2. Library rooms or Library halls

    Directory of Open Access Journals (Sweden)

    Alfredo Serrai


    Full Text Available Library Halls, understood as Renaissance and Baroque architectural creations, along with the furnishings and decorations, accomplish a cognitive task and serve to transmit knowledge. The design of these spaces based on the idea that they should reflect the merits and content of the collections housed within them, in order to prepare the mind of the reader to respect and admire the volumes. In accordance with this principle, in the fifteenth century library rooms had a basilican shape, with two or three naves, like churches, reflecting thus the spiritual value of the books contained there. Next to that inspiring function, library rooms had also the task of representing the entire logical and conceptual universe of human knowledge in a figurative way, including for this purpose also the and Kunst- und Wunderkammern, namely the collections of natural, artficial objects, and works of art. The importance of library rooms and their function was understood already in the early decades of the seventeenth century, as underlined in the treatise, Musei sive Bibliothecae tam privatae quam publicae Extructio, Instructio, Cura, Usus, written by the Jesuit Claude Clément and published in 1635. Almost the entire volume is dedicated to the decoration and ornamentation of the Saloni, and the function of the library is identified exclusively with the preservation and decoration of the collection, neglecting more specifically bibliographic aspects or those connected to library science. The architectural structure of the Saloni was destined to change in relation to two factors, namely the form of books, and the sources of light. As a consequence, from the end of the sixteenth century – or perhaps even before if one considers the fragments of the Library of Urbino belonging to Federico da Montefeltro – shelves and cabinets have been placed no longer in the center of the room, but were set against the walls. This new disposition of the furniture, surmounted by

  3. Influence of confined optical phonons and laser radiation on the hall effect in a compositional superlattice (United States)

    Bau, Nguyen Quang; Long, Do Tuan


    The effect of confined optical phonons and laser radiation are taken into account to study the Hall effect in a compositional semiconductor superlattice (CSSL). The new theoretical expressions of the Hall conductivity, the Hall coefficient and the magnetoresistance are obtained as functions of the external fields (the magnetic field B, the laser frequency Ω and amplitude E), the CSSL parameters (the well length dI, the barrier length dII and height U) and the quantum number m characterizing the phonon confinement effect. The magneto-confined phonon resonance condition in a CSSL is also carried out to explain the numerical evaluation results for the GaAs /AlxGa1-x As CSSL. When optical phonons are confined, the Hall conductivity has more resonance peaks in comparison with that for bulk phonons. In addition, these sub-peaks are more separate from the main peaks as the CSSL layers thickness decreases. The tighter CSSL period is, the more forcefully the phonon confinement makes. When the CSSL period d is smaller than 30 nm , the contribution of confined optical phonons is significant and could not be neglected. The magnetophonon resonance for bulk semiconductor could be achieved in the limit the CSSL period goes to infinity. Furthermore, the Hall conductivity increases and the Hall coefficient, the magnetoresistance decrease due to the laser radiation and the effect of confined optical phonons. Especially, the near-linear dependence of the magnetoresistance on temperature is in good agreement with the experimental result.

  4. Quantum Hall effect in quantum electrodynamics

    International Nuclear Information System (INIS)

    Penin, Alexander A.


    We consider the quantum Hall effect in quantum electrodynamics and find a deviation from the quantum-mechanical prediction for the Hall conductivity due to radiative antiscreening of electric charge in an external magnetic field. A weak dependence of the universal von Klitzing constant on the magnetic field strength, which can possibly be observed in a dedicated experiment, is predicted

  5. Reversal of the Hall field in indium

    International Nuclear Information System (INIS)

    Ozimek, E.J.; Leisure, R.G.; Hsu, D.K.


    The Hall effect in single crystal has been investigated at 63 kOe over the 6-280 K temperature range. The Hall coefficient reverses sign as a function of temperature. The high temperature value is less negative than theoretical predictions. (Auth.)

  6. Integral and fractional quantum Hall Ising ferromagnets

    Czech Academy of Sciences Publication Activity Database

    Výborný, Karel; Čertík, Ondřej; Pfannkuche, D.; Wodzinski, D.; Wójs, A.; Quinn, J.J.


    Roč. 75, č. 4 (2007), 045434/1-045434/10 ISSN 1098-0121 R&D Projects: GA MŠk LC510 Institutional research plan: CEZ:AV0Z10100521 Keywords : quantum Hall ferromagnet * fractional quantum Hall effect ( FQHE) * Ising ferromagnet * exact diagonalization Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.172, year: 2007

  7. Mesoscopic effects in the quantum Hall regime

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 58; Issue 2 ... Mesoscopic effects; quantum Hall transitions; finite-size scaling. ... When band mixing between multiple Landau levels is present, mesoscopic effects cause a crossover from a sequence of quantum Hall transitions for weak disorder to classical behavior ...

  8. The Scientific Humanism of G. Stanley Hall (United States)

    Meyer, Donald H.


    This paper presents the humanistic psychology of the pioneer American psychologist Granville Stanley Hall (1844-1924), examining Hall's effort to develop a system of psychology that is at once rigorously scientific and, simultaneously, capable of verifying essential human values. (Author)

  9. Novel optical probe for quantum Hall system

    Indian Academy of Sciences (India)

    to 8 T using SPV spectroscopy. Keywords. Surface photovoltage spectroscopy; quantum Hall effect; Landau levels; edge states. PACS Nos 73.43.-f; 07.60.-j; 73.43.Fj. 1. Introduction. Integer quantum Hall effect (QHE) arises from quantization of energy of two- dimensional electron gas (2DEG) under perpendicular magnetic ...

  10. Monitoring of Hall's Harbor wharf (United States)

    Newhook, John P.; Bakht, Baidar; Mufti, Aftab A.; Tadros, Gamil


    The Hall's Harbour wharf in Nova Scotia is the first Canadian project to demonstrate the application of fibre reinforced polymer reinforcement, the steel-free concrete deck slab concept and fibre optic monitoring systems to structures in the marine environment. The extreme environmental exposure conditions make the site an excellent location for testing both material performance and sensing system durability. The early results of the monitoring program indicate that the innovative structure is meeting service level performance requirements. Long-term durability assessment is continuing and being complemented by controlled field and laboratory testing programs. Continuous remote monitoring of the fibre optic sensors is producing valuable reinforcement strain information for tracking structural response to ambient conditions. The fibre optic sensors themselves were found to be rugged enough to withstand the construction process and exposure environment; however, further work is required to achieve feasible field units for some types of fibre optic sensing instruments and associated equipment.

  11. Transport measurements and simulations of GaAs/AlGaAs ``anti-Hall-bar within a Hall bar'' devices (United States)

    Kriisa, Annika; Mani, Ramesh G.


    Hall effect measurements are often carried out in the Hall geometry, which is a thin rectangular plate with current and Hall voltage contacts at the external boundary. The motivation of this study is to further understand the impact on Hall effect when a hole is inserted inside Hall geometry. One way on conducting this investigation is to superimpose an ``anti-Hall bar'' inside the standard Hall bar, where the anti Hall bar is actually the hole inside the Hall device with contacts on the inside boundary of this hole. This configuration is thought to generate an ordinary Hall effect within the interior boundary such that the interior Hall voltage divided by the interior injected current equals the Hall resistance. One believes that it might also be possible to simultaneously realize multiple independent Hall effects by injecting multiple currents into the multiply connected device [1]. We have studied Hall effect in the doubly connected ``anti-Hall bar within a Hall bar'' geometry fabricated out of the GaAs/AlGaAs semiconductor system. Also the simulations of the distribution of the Hall current and potential profile within the specimen are conducted. To attain understanding of how the Hall effect arises in this geometry, the simulation plots are compared to the experimental results. [1] R. G. Mani and K. von Klitzing, App. Phys. Lett. 1993, 64, 1262-1264.

  12. The quantum Hall effects: Philosophical approach (United States)

    Lederer, P.


    The Quantum Hall Effects offer a rich variety of theoretical and experimental advances. They provide interesting insights on such topics as gauge invariance, strong interactions in Condensed Matter physics, emergence of new paradigms. This paper focuses on some related philosophical questions. Various brands of positivism or agnosticism are confronted with the physics of the Quantum Hall Effects. Hacking's views on Scientific Realism, Chalmers' on Non-Figurative Realism are discussed. It is argued that the difficulties with those versions of realism may be resolved within a dialectical materialist approach. The latter is argued to provide a rational approach to the phenomena, theory and ontology of the Quantum Hall Effects.

  13. Quantized Hall conductance as a topological invariant

    International Nuclear Information System (INIS)

    Niu, Q.; Thouless, Ds.J.; Wu, Y.S.


    Whenever the Fermi level lies in a gap (or mobility gap) the bulk Hall conductance can be expressed in a topologically invariant form showing the quantization explicitly. The new formulation generalizes the earlier result by TKNN to the situation where many body interaction and substrate disorder are also present. When applying to the fractional quantized Hall effect we draw the conclusion that there must be a symmetry breaking in the many body ground state. The possibility of writing the fractionally quantized Hall conductance as a topological invariant is also carefully discussed. 19 references

  14. Integrated Stirling Convertor and Hall Thruster Test Conducted (United States)

    Mason, Lee S.


    An important aspect of implementing Stirling Radioisotope Generators on future NASA missions is the integration of the generator and controller with potential spacecraft loads. Some recent studies have indicated that the combination of Stirling Radioisotope Generators and electric propulsion devices offer significant trip time and payload fraction benefits for deep space missions. A test was devised to begin to understand the interactions between Stirling generators and electric thrusters. An electrically heated RG- 350 (350-W output) Stirling convertor, designed and built by Stirling Technology Company of Kennewick, Washington, under a NASA Small Business Innovation Research agreement, was coupled to a 300-W SPT-50 Hall-effect thruster built for NASA by the Moscow Aviation Institute (RIAME). The RG-350 and the SPT-50 shown, were installed in adjacent vacuum chamber ports at NASA Glenn Research Center's Electric Propulsion Laboratory, Vacuum Facility 8. The Stirling electrical controller interfaced directly with the Hall thruster power-processing unit, both of which were located outside of the vacuum chamber. The power-processing unit accepted the 48 Vdc output from the Stirling controller and distributed the power to all the loads of the SPT-50, including the magnets, keeper, heater, and discharge. On February 28, 2001, the Glenn test team successfully operated the Hall-effect thruster with the Stirling convertor. This is the world's first known test of a dynamic power source with electric propulsion. The RG-350 successfully managed the transition from the purely resistive load bank within the Stirling controller to the highly capacitive power-processing unit load. At the time of the demonstration, the Stirling convertor was operating at a hot temperature of 530 C and a cold temperature of -6 C. The linear alternator was producing approximately 250 W at 109 Vac, while the power-processing unit was drawing 175 W at 48 Vdc. The majority of power was delivered to the

  15. Permanent resident

    Directory of Open Access Journals (Sweden)

    John F. Fisher


    Full Text Available The training of physicians in the past century was based primarily on responsibility and the chain-of-command. Those with the bulk of that responsibility in the fields of pediatrics and internal medicine were residents. Residents trained the medical students and supervised them carefully in caring for patients. Most attending physicians supervised their teams at arm's length, primarily serving as teachers of the finer points of diagnosis and treatment during set periods of the day or week with a perfunctory signature on write-ups or progress notes. Residents endeavored to protect the attending physician from being heavily involved unless they were unsure about a clinical problem. Before contacting the attending physician, a more senior resident would be called. Responsibility was the ultimate teacher. The introduction of diagnosis-related groups by the federal government dramatically changed the health care delivery system, placing greater emphasis on attending physician visibility in the medical record, ultimately resulting in more attending physician involvement in day-to-day care of patients in academic institutions. Without specified content in attending notes, hospital revenues would decline. Although always in charge technically, attending physicians increasingly have assumed the role once dominated by the resident. Using biographical experiences of more than 40 years, the author acknowledges and praises the educational role of responsibility in his own training and laments its declining role in today's students and house staff.

  16. Permanent resident. (United States)

    Fisher, John F


    The training of physicians in the past century was based primarily on responsibility and the chain-of-command. Those with the bulk of that responsibility in the fields of pediatrics and internal medicine were residents. Residents trained the medical students and supervised them carefully in caring for patients. Most attending physicians supervised their teams at arm's length, primarily serving as teachers of the finer points of diagnosis and treatment during set periods of the day or week with a perfunctory signature on write-ups or progress notes. Residents endeavored to protect the attending physician from being heavily involved unless they were unsure about a clinical problem. Before contacting the attending physician, a more senior resident would be called. Responsibility was the ultimate teacher. The introduction of diagnosis-related groups by the federal government dramatically changed the health care delivery system, placing greater emphasis on attending physician visibility in the medical record, ultimately resulting in more attending physician involvement in day-to-day care of patients in academic institutions. Without specified content in attending notes, hospital revenues would decline. Although always in charge technically, attending physicians increasingly have assumed the role once dominated by the resident. Using biographical experiences of more than 40 years, the author acknowledges and praises the educational role of responsibility in his own training and laments its declining role in today's students and house staff.

  17. Resident-Led Palliative Care Education Project. (United States)

    Karlen, Naomi; Cruz, Brian; Leigh, A E


    Despite the growth of palliative medicine, 39% of hospitals do not have palliative care teams for consultation or to provide resident education. We examined the impact of resident-led education in palliative care principles on attitudes toward and comfort with palliative medicine and end-of-life care among internal medicine residents. An educational module designed by the authors was presented to other internal medicine residents in the program. Pre- and post-intervention survey data measuring residents' agreement with various statements regarding palliative medicine and end-of-life care were analyzed. Residents' agreement with various statements regarding palliative medicine and end-of-life care on a 5-point Likert scale was analyzed. Following the intervention, participants reported improved comfort with general knowledge of palliative medicine (p palliative care and end-of-life care (p curriculum in palliative medicine can improve resident comfort within this still-under-represented area of medicine.

  18. Spin Hall effect, Hall effect and spin precession in diffusive normal metals


    Shchelushkin, R. V.; Brataas, Arne


    We study transport in normal metals in an external magnetic field. This system exhibits an interplay between a transverse spin imbalance (spin Hall effect) caused by the spin-orbit interaction, a Hall effect via the Lorentz force, and spin precession due to the Zeeman effect. Diffusion equations for spin and charge flow are derived. The spin and charge accumulations are computed numerically in experimentally relevant thin film geometries. The out-of-plane spin Hall potential is suppressed whe...

  19. Topologically induced fractional Hall steps in the integer quantum Hall regime of MoS 2 (United States)

    Firoz Islam, SK; Benjamin, Colin


    The quantum magnetotransport properties of a monolayer of molybdenum disulfide are derived using linear response theory. In particular, the effect of topological terms on longitudinal and Hall conductivity is analyzed. The Hall conductivity exhibits fractional steps in the integer quantum Hall regime. Further complete spin and valley polarization of the longitudinal conductivitity is seen in presence of these topological terms. Finally, the Shubnikov-de Hass oscillations are suppressed or enhanced contingent on the sign of these topological terms.

  20. Nonlocal interaction of inverse magnetic energy transfer in hall magnetohydrodynamic turbulence

    International Nuclear Information System (INIS)

    Araki, Keisuke; Miura, Hideaki


    A detailed analysis of forward and inverse energy transfer processes due to the Hall term effect in freely decaying, homogeneous, isotropic Hall magnetohydrodynamics (HMHD) turbulence is performed through Fourier and wavelet analyses. We analyzed three snapshot datasets that were taken from such a period to allow the turbulence to develop sufficiently with a nearly constant magnetic Reynolds number. Because the Fourier energy spectra in these snapshots show remarkable agreement after the normalization in terms of the dissipation rates and the diffusion coefficients, they are considered as a universal equilibrium state. By analyzing the numerical solutions that are generated without any external forcing, it is confirmed that the inverse energy transfer due to the Hall term effect is intrinsic to HMHD dynamics. Orthonormal divergence-free wavelet analysis reveals that nonlinear mode interactions contributing to the inverse energy transfer exhibit a nonlocal feature, while those for the forward transfer are dominated by a local feature. (author)

  1. Bound values for Hall conductivity of heterogeneous medium under ...

    Indian Academy of Sciences (India)

    Bound values for Hall conductivity under quantum Hall effect (QHE) conditions in inhomogeneous medium has been studied. It is shown that bound values for Hall conductivity differ from bound values for metallic conductivity. This is due to the unusual character of current percolation under quantum Hall effect conditions.

  2. Athletics hall, Odenwald school, Heppenheim, Germany

    Energy Technology Data Exchange (ETDEWEB)

    Schuler, M. [Trans Solar GmbH, Stuttgart (Germany)


    This building, completed in 1995, is a good example of how to use a glazed foyer, not only as a climatic buffer zone, but also for preheating the inlet air by solar gains. The completely glazed west-oriented foyer is used as a huge air collector to preheat ventilation air during the heating period. The glass superstructure across the hall stores a movable curtain, serves as a skylight and enhances the natural ventilation of the hall due to the chimney effect. The stiffening ribs of the floor are also used as an air duct to the hall and as an installation duct. Photovoltaic-powered fans are used to move solar preheated air into the hall. (author)

  3. AA under construction in its hall

    CERN Multimedia

    CERN PhotoLab


    The Antiproton Accumulator was installed in a specially built hall. Here we see it at an "early" stage of installation, just a few magnets on the floor, no vacuum chamber at all, but: 3 months later there was circulating beam !

  4. Multiscale Modeling of Hall Thrusters Project (United States)

    National Aeronautics and Space Administration — New multiscale modeling capability for analyzing advanced Hall thrusters is proposed. This technology offers NASA the ability to reduce development effort of new...

  5. Light Metal Propellant Hall Thruster, Phase I (United States)

    National Aeronautics and Space Administration — Busek proposes to develop light metal Hall Effect thrusters that will help reduce the travel time, mass, and cost of SMD spacecraft. Busek has identified three...

  6. Mesoscopic effects in the quantum Hall regime

    Indian Academy of Sciences (India)

    The seven magnetic sub-bands are well separated by energy gaps at disorder strengthW =0.5. The Hall conductance of each of the q magnetic sub-bands, when they are separated by energy gaps, have been shown to be quantized [13]. The Hall conductance σ r (in units of e2/h), when the lowest r sub-bands are occupied, ...

  7. Hall effect in organic layered conductors

    Directory of Open Access Journals (Sweden)



    Full Text Available The Hall effect in organic layered conductors with a multisheeted Fermi surfaces was considered. It is shown that the experimental study of Hall effect and magnetoresistance anisotropy at different orientations of current and a quantizing magnetic field relative to the layers makes it possible to determine the contribution of various charge carriers groups to the conductivity, and to find out the character of Fermi surface anisotropy in the plane of layers.

  8. Adding Breadth and Depth to College and University Residential Communities: A Phenomenological Study of Faculty-in-Residence (United States)

    Davenport, Amy M.; Pasque, Penny A.


    Faculty-in-residence programs in residence halls are unique opportunities for student-faculty involvement, with high levels of commitment from faculty, students, staff, and institutional resources. This hermeneutic phenomenological study explores a faculty-in-residence program at a four-year public university where the FIR program has resulted in…

  9. License Agreements concerning trademarks


    Dráb, Ladislav


    The thesis deals with license agreements in relation to trademarks, specially the trademark license agreement. The thesis contains in its theoretical interpretation of the concept and sources of the license agreement. There are also analyzed various types of license agreements, including modifying the license agreement in the new Civil Code, and related types of contracts as a franchising or merchandising. Another interpretation is more concerned with trademark and trademark license agreement...

  10. 75 FR 22770 - Gary E. Hall and Rita Hall; Notice of Availability of Environmental Assessment (United States)


    ... project and concludes that exempting the project from licensing, with appropriate environmental measures.... Hall and Rita Hall; Notice of Availability of Environmental Assessment April 22, 2010. In accordance with the National Environmental Policy Act of 1969, as amended, and the Federal Energy Regulatory...

  11. Agreement Workflow Tool (AWT) (United States)

    Social Security Administration — The Agreement Workflow Tool (AWT) is a role-based Intranet application used for processing SSA's Reimbursable Agreements according to SSA's standards. AWT provides...

  12. Nonlinear magnetotransport theory and Hall induced resistance oscillations in graphene. (United States)

    Gutiérrez-Jáuregui, R; Torres, M


    The quantum oscillations of nonlinear magnetoresistance in graphene that occur in response to a dc current bias are investigated. We present a theoretical model for the nonlinear magnetotransport of graphene carriers. The model is based on the exact solution of the effective Dirac equation in crossed electric and magnetic fields, while the effects of randomly distributed impurities are perturbatively added. To compute the nonlinear current effects, we develop a covariant formulation of the migration center theory. The current is calculated for short- and large-range scatterers. The analysis of the differential resistivity in the large magnetic field region, shows that the extrema of the Shubnikov de Hass oscillations invert when the dc currents exceed a threshold value. These results are in good agreement with experimental observations. In the small magnetic field regime, corresponding to large filling factors, the existence of Hall induced resistance oscillations are predicted for ultra clean graphene samples. These oscillations originate from Landau-Zener tunneling between Landau levels, that are tilted by the strong electric Hall field.

  13. Chiral Luttinger liquids at the fractional quantum Hall edge (United States)

    Chang, A. M.


    The edges of quantum Hall fluids behave as one-dimensional conductors. This article reviews electron transport into these edge states, covering both the theory based on the chiral Luttinger liquid and the experimental findings using electron tunneling as the probe. The first part of the review presents a basic description of this theory, including a derivation of the density of states, to provide a framework and language for discussing the experimental observations. The signature of the chiral Luttinger liquid is a power-law behavior for the density of states and the tunneling conductances. Experimentally, two techniques have been applied to study the tunneling conductance, using a gated point contact between two quantum Hall edges, or using a cleaved-edge barrier between an edge and a normal conductor. The point-contact method exhibits resonant tunneling, which appears to show some aspects of the Luttinger liquid, and the cleaved-edge method has yielded clear power-law dependences in the off-resonance conductances. Power-law behavior over many orders of magnitude is observed, confirming the Luttinger-liquid character of the edge states. However, the power-law exponents, while in agreement with finite-size numerical calculations, can differ from the universal values predicted by the Chern-Simon field theory. This disagreement is still not well understood. The review concludes with a brief survey of other one-dimensional conductors that have been studied to look for characteristics of the nonchiral Tomonaga-Luttinger liquid.

  14. Air temperature gradient in large industrial hall (United States)

    Karpuk, Michał; Pełech, Aleksander; Przydróżny, Edward; Walaszczyk, Juliusz; Szczęśniak, Sylwia


    In the rooms with dominant sensible heat load, volume airflow depends on many factors incl. pre-established temperature difference between exhaust and supply airflow. As the temperature difference is getting higher, airflow volume drops down, consequently, the cost of AHU is reduced. In high industrial halls with air exhaust grids located under the ceiling additional temperature gradient above working zone should be taken into consideration. In this regard, experimental research of the vertical air temperature gradient in high industrial halls were carried out for the case of mixing ventilation system The paper presents the results of air temperature distribution measurements in high technological hall (mechanically ventilated) under significant sensible heat load conditions. The supply airflow was delivered to the hall with the help of the swirl diffusers while exhaust grids were located under the hall ceiling. Basing on the air temperature distribution measurements performed on the seven pre-established levels, air temperature gradient in the area between 2.0 and 7.0 m above the floor was calculated and analysed.

  15. Extrinsic spin Hall effect in graphene (United States)

    Rappoport, Tatiana

    The intrinsic spin-orbit coupling in graphene is extremely weak, making it a promising spin conductor for spintronic devices. In addition, many applications also require the generation of spin currents in graphene. Theoretical predictions and recent experimental results suggest one can engineer the spin Hall effect in graphene by greatly enhancing the spin-orbit coupling in the vicinity of an impurity. The extrinsic spin Hall effect then results from the spin-dependent skew scattering of electrons by impurities in the presence of spin-orbit interaction. This effect can be used to efficiently convert charge currents into spin-polarized currents. I will discuss recent experimental results on spin Hall effect in graphene decorated with adatoms and metallic cluster and show that a large spin Hall effect can appear due to skew scattering. While this spin-orbit coupling is small if compared with what it is found in metals, the effect is strongly enhanced in the presence of resonant scattering, giving rise to robust spin Hall angles. I will present our single impurity scattering calculations done with exact partial-wave expansions and complement the analysis with numerical results from a novel real-space implementation of the Kubo formalism for tight-binding Hamiltonians. The author acknowledges the Brazilian agencies CNPq, CAPES, FAPERJ and INCT de Nanoestruturas de Carbono for financial support.

  16. Field theory approach to quantum hall effect

    International Nuclear Information System (INIS)

    Cabo, A.; Chaichian, M.


    The Fradkin's formulation of statistical field theory is applied to the Coulomb interacting electron gas in a magnetic field. The electrons are confined to a plane in normal 3D-space and also interact with the physical 3D-electromagnetic field. The magnetic translation group (MTG) Ward identities are derived. Using them it is shown that the exact electron propagator is diagonalized in the basis of the wave functions of the free electron in a magnetic field whenever the MTG is unbroken. The general tensor structure of the polarization operator is obtained and used to show that the Chern-Simons action always describes the Hall effect properties of the system. A general proof of the Streda formula for the Hall conductivity is presented. It follows that the coefficient of the Chern-Simons terms in the long-wavelength approximation is exactly given by this relation. Such a formula, expressing the Hall conductivity as a simple derivative, in combination with diagonal form of the full propagator allows to obtain a simple expressions for the filling factor and the Hall conductivity. Indeed, these results, after assuming that the chemical potential lies in a gap of the density of states, lead to the conclusion that the Hall conductivity is given without corrections by σ xy = νe 2 /h where ν is the filling factor. In addition it follows that the filling factor is independent of the magnetic field if the chemical potential remains in the gap. (author). 21 ref, 1 fig

  17. Experimental probes of emergent symmetries in the quantum Hall system

    CERN Document Server

    Lutken, C A


    Experiments studying renormalization group flows in the quantum Hall system provide significant evidence for the existence of an emergent holomorphic modular symmetry Gamma(0)(2). We briefly review this evidence and show that, for the lowest temperatures, the experimental determination of the position of the quantum critical points agrees to the parts per mille level with the prediction from Gamma(0)(2). We present evidence that experiments giving results that deviate substantially from the symmetry predictions are not cold enough to be in the quantum critical domain. We show how the modular symmetry extended by a non-holomorphic particle hole duality leads to an extensive web of dualities related to those in plateau insulator transitions, and we derive a formula relating dual pairs (B, B(d)) of magnetic field strengths across any transition. The experimental data obtained for the transition studied so far is in excellent agreement with the duality relations following from this emergent symmetry, and rule out...

  18. Residency training program: Perceptions of residents

    African Journals Online (AJOL)

    Abstract. Background: There is a phobia among doctors for the residency training program, since the establishment of ... Materials and Methods: Structured questionnaires were administered to residents at 3 training institutions in Nigeria. Results: ... Keywords: Decentralization, motivation, perception, remuneration, residents.

  19. Shielding consideration for the SSCL experimental halls

    International Nuclear Information System (INIS)

    Bull, J.; Coyne, J.; Mokhov, N.; Stapleton, G.


    The Superconducting Super Collider which is being designed and built in Waxahachie, Texas consists Of series of proton accelerators, culminating in a 20 Te proton on proton collider. The collider will be in a tunnel which will be 87 km in circumference and. on average about 30 meters underground. The present design calls for two large interaction halls on the east side of the ring. The shielding for these halls is being designed for an interaction rate of 10 9 Hz or 10 16 interactions per year, based on 10 7 seconds per operational year. SSC guidelines require that the shielding be designed to meet the criterion of 1mSv per year for open areas off site 2mSv per year for open areas on site, and 2mSv per year for controlled areas. Only radiation workers will be routinely allowed to work in controlled areas. It should be pointed that there is a potential for an accidental full beam loss in either of the experimental halls, and this event would consist of the loss of the full circulating beam up to 4 x 10 14 protons. With the present design. the calculated dose equivalent for this event is about 10% of the annual dose equivalent for the normal p-p interactions, so that die accident condition does not control the shielding. If, for instance, local shielding within the experimental hall is introduced into the calculations, this could change. The shielding requirements presented here are controlled by the normal p-p interactions. Three important questions were addressed in the present calculations. They are (1) the thickness of the roof over the experimental halls, (2) the configuration of the shafts and adits which give access to the halls, and (3) the problem of ground water and air activation

  20. Enhanced Performance of Cylindrical Hall Thrusters

    International Nuclear Information System (INIS)

    Raitses, Y.; Smirnov, A.; Fisch, N.J.


    The cylindrical thruster differs significantly in its underlying physical mechanisms from the conventional annular Hall thruster. It features high ionization efficiency, quiet operation, ion acceleration in a large volume-to-surface ratio channel, and performance comparable with the state-of-the-art conventional Hall thrusters. Very significant plume narrowing, accompanied by the increase of the energetic ion fraction and improvement of ion focusing, led to 50-60% increase of the thruster anode efficiency. These improvements were achieved by overrunning the discharge current in the magnetized thruster plasma

  1. Prototype dining hall energy efficiency study

    Energy Technology Data Exchange (ETDEWEB)

    Mazzucchi, R.P.; Bailey, S.A.; Zimmerman, P.W.


    The energy consumption of food service facilities is among the highest of any commercial building type, owing to the special requirements for food preparation, sanitation, and ventilation. Consequently, the US Air Force Engineering and Services Center (AFESC) contracted with Pacific Northwest Laboratory (PNL) to collect and analyze end-use energy consumption data for a prototypical dining hall and make specific recommendations on cost-effective energy conservation options. This information will be used to establish or update criteria for dining hall designs and retrofits as appropriate. 6 refs., 21 figs., 23 tabs.

  2. The Refined Lecture Hall Theorem via Abacus Diagrams


    Bradford, Laura; Harris, Meredith; Jones, Brant; Komarinski, Alex; Matson, Carly; O'Shea, Edwin


    Bousquet-M\\'elou & Eriksson's lecture hall theorem generalizes Euler's celebrated distinct-odd partition theorem. We present an elementary and transparent proof of a refined version of the lecture hall theorem using a simple bijection involving abacus diagrams.

  3. Bound values for Hall conductivity of heterogeneous medium under ...

    Indian Academy of Sciences (India)

    - ditions in inhomogeneous medium has been studied. It is shown that bound values for. Hall conductivity differ from bound values for metallic conductivity. This is due to the unusual character of current percolation under quantum Hall effect ...

  4. Ion instabilities in the Hall plasma

    International Nuclear Information System (INIS)

    Gordeev, A.V.; Grechina, A.V.


    Instabilities of the Hall plasma are investigated to study the properties of plasma with small ion number per unit length, taking into account ion dynamics and electron mass finiteness. The availability of a universal mechanism resulting in a high two-stream instability with maximum increment of (ω Hi ω He ) 1/2 order is shown

  5. Pseudospin anisotropy classification of quantum Hall ferromagnets

    Czech Academy of Sciences Publication Activity Database

    Jungwirth, Tomáš; MacDonald, A. H.


    Roč. 63, č. 3 (2000), s. 035305-1 - 035305-9 ISSN 0163-1829 R&D Projects: GA ČR GA202/98/0085 Institutional research plan: CEZ:AV0Z1010914 Keywords : quantum Hall ferromagnets * anisotropy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.065, year: 2000

  6. Anomalous Hall conductivity: Local orbitals approach

    Czech Academy of Sciences Publication Activity Database

    Středa, Pavel


    Roč. 82, č. 4 (2010), 045115/1-045115/9 ISSN 1098-0121 Institutional research plan: CEZ:AV0Z10100521 Keywords : anomalous Hall effect * Berry phase correction * orbital polarization momentum Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.772, year: 2010

  7. Intrinsic anomalous Hall effect and local polarizabilities

    Czech Academy of Sciences Publication Activity Database

    Středa, Pavel; Jonckheere, T.


    Roč. 82, č. 11 (2010), 113303/1-113303/4 ISSN 1098-0121 R&D Projects: GA ČR GA202/08/0551 Institutional research plan: CEZ:AV0Z10100521 Keywords : orbital polarization momentum * Berry phase correction * anomalous Hall effect Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.772, year: 2010

  8. Surprises from the spin Hall effect

    Czech Academy of Sciences Publication Activity Database

    Sinova, Jairo; Jungwirth, Tomáš


    Roč. 70, č. 7 (2017), s. 39-42 ISSN 0031-9228 Institutional support: RVO:68378271 Keywords : spintronics * spin Hall effect * magnetic recording Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 4.188, year: 2016

  9. Chapin Hall Projects and Publications. Autumn 1999. (United States)

    Chicago Univ., IL. Chapin Hall Center for Children.

    This guide chronicles the ongoing work and writings of the Chapin Hall Center for Children at the University of Chicago, a policy research center dedicated to bringing sound information, rigorous analyses, innovative ideas, and an independent, multidisciplinary perspective to bear on policies and programs affecting children. This guide, organized…

  10. Anomalous Hall effect in disordered multiband metals

    Czech Academy of Sciences Publication Activity Database

    Kovalev, A.A.; Sinova, Jairo; Tserkovnyak, Y.


    Roč. 105, č. 3 (2010), 036601/1-036601/4 ISSN 0031-9007 Institutional research plan: CEZ:AV0Z10100521 Keywords : anomalous Hall effect * spintronics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.621, year: 2010

  11. Individualization in a Lecture Hall Setting. (United States)

    Halyard, Rebecca A.

    A two-quarter Human Anatomy and Physiology course for health-science students has been developed which incorporates the principles of individualization while maintaining the lecture hall setting. The lecture method contributes the following components to the course: (1) no special equipment or supplies; (2) personal interaction between instructor…

  12. line wear debris hall effect sensor

    African Journals Online (AJOL)



    Jul 2, 2013 ... environmental monitoring/control, use of low noise electronic components and method of opposing environmental ... Keywords: Hall Effect, sensor, noise reduction, hysteresis, temperature dependent drift, stability, full scale deflection, ... must conform to available standards and the characteristics must be.

  13. Spin Hall effect on a noncommutative space

    International Nuclear Information System (INIS)

    Ma Kai; Dulat, Sayipjamal


    We study the spin-orbital interaction and the spin Hall effect of an electron moving on a noncommutative space under the influence of a vector potential A(vector sign). On a noncommutative space, we find that the commutator between the vector potential A(vector sign) and the electric potential V 1 (r(vector sign)) of the lattice induces a new term, which can be treated as an effective electric field, and the spin Hall conductivity obtains some correction. On a noncommutative space, the spin current and spin Hall conductivity have distinct values in different directions, and depend explicitly on the noncommutative parameter. Once this spin Hall conductivity in different directions can be measured experimentally with a high level of accuracy, the data can then be used to impose bounds on the value of the space noncommutativity parameter. We have also defined a new parameter, σ=ρθ (ρ is the electron concentration, θ is the noncommutativity parameter), which can be measured experimentally. Our approach is based on the Foldy-Wouthuysen transformation, which gives a general Hamiltonian of a nonrelativistic electron moving on a noncommutative space.

  14. Inertial-Hall effect: the influence of rotation on the Hall conductivity

    Directory of Open Access Journals (Sweden)

    Julio E. Brandão


    Full Text Available Inertial effects play an important role in classical mechanics but have been largely overlooked in quantum mechanics. Nevertheless, the analogy between inertial forces on mass particles and electromagnetic forces on charged particles is not new. In this paper, we consider a rotating non-interacting planar two-dimensional electron gas with a perpendicular uniform magnetic field and investigate the effects of the rotation in the Hall conductivity. The rotation introduces a shift and a split in the Landau levels. As a consequence of the break of the degeneracy, the counting of the states fully occupied below the Fermi energy increases, tuning the Hall quantization steps. The rotation also changes the quantum Hall plateau widths. Additionally, we find the Hall quantization steps as a function of rotation at a fixed value of the magnetic field.

  15. Chiral heat transport in driven quantum Hall and spin Hall edge states (United States)

    Arrachea, Liliana; Fradkin, Eduardo


    We consider a model for an edge state of electronic systems in the quantum Hall regime with filling ν=1 as well as in the quantum spin Hall regime. In both cases the system is in contact with two reservoirs by tunneling at point contacts. Both systems are locally driven by applying an ac voltage in one of the contacts. By weakly coupling them to a third reservoir, the transport of the generated heat is studied in two different ways: i) when the third reservoir acts as a thermometer the local temperature is sensed, and ii) when the third reservoir acts as a voltage probe the time-dependent local voltage is sensed. Our results indicate a chiral propagation of the heat along the edge in the quantum Hall case and in the quantum spin Hall case (if the injected electrons are spin polarized). The temperature profile shows that electrons along the edge thermalize with the closest upstream reservoir.

  16. Digital technology impacts on the Arnhem transfer hall structural design

    NARCIS (Netherlands)

    Van de Straat, R.; Hofman, S.; Coenders, J.L.; Paul, J.C.


    The new Transfer Hall in Arnhem is one of the key projects to prepare the Dutch railways for the increased future demands for capacity. UNStudio developed a master plan in 1996 for the station area of which the completion of the Transfer Hall in 2015 will be a final milestone. The Transfer Hall is a

  17. Magnetoresistance in quantum Hall metals due to Pancharatnam ...

    Indian Academy of Sciences (India)

    We derive the trial Hall resistance formula for the quantum Hall metals to address both the integer and fractional quantum Hall effects. Within the degenerate (and crossed) Landau levels, and in the presence of changing magnetic field strength, one can invoke two physical processes responsible for the electron conduction ...

  18. Magnetoresistance in quantum Hall metals due to Pancharatnam ...

    Indian Academy of Sciences (India)

    Abstract. We derive the trial Hall resistance formula for the quantum Hall metals to address both the integer and fractional quantum Hall effects. Within the degenerate (and crossed) Landau levels, and in the presence of changing magnetic field strength, one can invoke two physical processes responsible for the electron ...

  19. Nuclear cooperation agreements

    International Nuclear Information System (INIS)

    Nuclear cooperation agreements are reviewed in tabular form, especially agreements with developing countries. The reporting countries are the USA, the Federal Republic of Germany, Canada, Australia, Japan, and France. A separate EURATOM list is annexed

  20. Hybrid-PIC Modeling of the Transport of Atomic Boron in a Hall Thruster (United States)

    Smith, Brandon D.; Boyd, Iaian D.; Kamhawi, Hani


    Computational analysis of the transport of boron eroded from the walls of a Hall thruster is performed by implementing sputter yields of hexagonal boron nitride and velocity distribution functions of boron within the hybrid-PIC model HPHall. The model is applied to simulate NASA's HiVHAc Hall thruster at a discharge voltage of 500V and discharge powers of 1-3 kW. The number densities of ground- and 4P-state boron are computed. The density of ground-state boron is shown to be a factor of about 30 less than the plasma density. The density of the excited state is shown to be about three orders of magnitude less than that of the ground state, indicating that electron impact excitation does not significantly affect the density of ground-state boron in the discharge channel or near-field plume of a Hall thruster. Comparing the rates of excitation and ionization suggests that ionization has a greater influence on the density of ground-state boron, but is still negligible. The ground-state boron density is then integrated and compared to cavity ring-down spectroscopy (CRDS) measurements for each operating point. The simulation results show good agreement with the measurements for all operating points and provide evidence in support of CRDS as a tool for measuring Hall thruster erosion in situ.

  1. Diagnostics Systems for Permanent Hall Thrusters Development (United States)

    Ferreira, Jose Leonardo; Soares Ferreira, Ivan; Santos, Jean; Miranda, Rodrigo; Possa, M. Gabriela

    This work describes the development of Permanent Magnet Hall Effect Plasma Thruster (PHALL) and its diagnostic systems at The Plasma Physics Laboratory of University of Brasilia. The project consists on the construction and characterization of plasma propulsion engines based on the Hall Effect. Electric thrusters have been employed in over 220 successful space missions. Two types stand out: the Hall-Effect Thruster (HET) and the Gridded Ion Engine (GIE). The first, which we deal with in this project, has the advantage of greater simplicity of operation, a smaller weight for the propulsion subsystem and a longer shelf life. It can operate in two configurations: magnetic layer and anode layer, the difference between the two lying in the positioning of the anode inside the plasma channel. A Hall-Effect Thruster-HET is a type of plasma thruster in which the propellant gas is ionized and accelerated by a magneto hydrodynamic effect combined with electrostatic ion acceleration. So the essential operating principle of the HET is that it uses a J x B force and an electrostatic potential to accelerate ions up to high speeds. In a HET, the attractive negative charge is provided by electrons at the open end of the Thruster instead of a grid, as in the case of the electrostatic ion thrusters. A strong radial magnetic field is used to hold the electrons in place, with the combination of the magnetic field and the electrostatic potential force generating a fast circulating electron current, the Hall current, around the axis of the Thruster, mainly composed by drifting electrons in an ion plasma background. Only a slow axial drift towards the anode occurs. The main attractive features of the Hall-Effect Thruster are its simple design and operating principles. Most of the Hall-Effect Thrusters use electromagnet coils to produce the main magnetic field responsible for plasma generation and acceleration. In this paper we present a different new concept, a Permanent Magnet Hall

  2. Anomalous field dependence of the Hall coefficient in disordered metals

    International Nuclear Information System (INIS)

    Tousson, E.; Ovadyahu, Z.


    We report on a comprehensive study of the Hall coefficient, R/sub H/, in disordered three-dimensional In 2 O/sub 3-//sub x/ films as a function of the magnetic field strength, temperature, and degree of spatial disorder. Our main result is that, at sufficiently small fields, R/sub H/ is virtually temperature, field, and disorder independent, even at the metal-insulator transition itself. On the other hand, at the limit of strong magnetic fields, R/sub H/ has an explicit temperature dependence, in apparent agreement with the prediction of Al'tshuler, Aronov, and Lee. For intermediate values of fields, R/sub H/ is field and temperature dependent. It is also shown that the behavior of the conductivity as a function of temperature, σ(T), at small fields, is qualitatively different than that measured at the limit of strong magnetic fields. The low- and high-field regimes seem to correlate with the respective regimes in terms of the Hall-coefficient behavior. It is suggested that the magnetotransport in the high-field limit is considerably influenced by Coulomb-correlation effects. However, in the low-field regime, where both correlations and weak-localization effects are, presumably, equally important (and where both theories are the more likely to be valid), is problematic; neither R/sub H/ nor σ(T) gives any unambiguous evidence to the existence of interaction effects. This problem is discussed in light of the experimental results pertaining to the behavior of R/sub H/(T) in two-dimensional In 2 O/sub 3-//sub x/ films as well as in other disordered systems

  3. The ``cinquefoil" resistive/Hall measurement geometry (United States)

    Koon, Daniel W.


    This talk begins by analyzing the charge transport weighting functions -- the sensitivity of resistive and Hall measurements to local macroscopic inhomogeneities -- of bridge-shaped transport specimens. As expected, such measurements sample only that region of the specimen between the central voltage electrodes, in the limit of narrow current channels connected by even narrower arms to the voltage electrodes. The bridge geometry has a few advantages over the van der Pauw cloverleaf geometry -- including ease in zeroing out the null-field Hall voltage -- but also some disadvantages. The talk concludes with an analysis of a hybrid geometry, the “cinquefoil” or five-leafed clover, which combines the best features of both.

  4. Induced radioisotopes in a linac treatment hall. (United States)

    Vega-Carrillo, Héctor René; de Leon-Martinez, Héctor Asael; Rivera-Perez, Esteban; Luis Benites-Rengifo, Jorge; Gallego, Eduardo; Lorente, Alfredo


    When linacs operate above 8MV an undesirable neutron field is produced whose spectrum has three main components: the direct spectrum due to those neutrons leaking out from the linac head, the scattered spectrum due to neutrons produced in the head that collides with the nuclei in the head losing energy and the third spectrum due to room-return effect. The third category of spectrum has mainly epithermal and thermal neutrons being constant at any location in the treatment hall. These neutrons induce activation in the linac components, the concrete walls and in the patient body. Here the induced radioisotopes have been identified in concrete samples located in the hall and in one of the wedges. The identification has been carried out using a gamma-ray spectrometer. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Stuart Hall and Cultural Studies, circa 1983

    Directory of Open Access Journals (Sweden)

    Ann Curthoys


    Full Text Available Stuart Hall sought to internationalise theoretical debates and to create Cultural Studies as interdisciplinary. We chart his theoretical journey through a detailed examination of a series of lectures delivered in 1983 and now published for the first time. In these lectures, he discusses theorists such as E.P. Thompson, Raymond Williams, Louis Althusser, Levi Strauss and Antonio Gramsci, and explores the relationship between ideas and social structure, the specificities of class and race, and the legacies of slavery. We note his turn towards metaphors of divergence and dispersal and highlight how autobiographical and deeply personal Hall is in these lectures, especially in his ego histoire moment of traumatic memory recovery.

  6. Theory of fractional quantum hall effect

    International Nuclear Information System (INIS)

    Kostadinov, I.Z.


    A theory of the Fractional Quantum Hall Effect is constructed based on magnetic flux fractionization, which lead to instability of the system against selfcompression. A theorem is proved stating that arbitrary potentials fail to lift a specific degeneracy of the Landau level. For the case of 1/3 fractional filling a model 3-particles interaction is constructed breaking the symmetry. The rigid 3-particles wave function plays the role of order parameter. In a BCS type of theory the gap in the single particles spectrum is produced by the 3-particles interaction. The mean field critical behaviour and critical parameters are determined as well as the Ginsburg-Landau equation coefficients. The Hall conductivity is calculated from the first principles and its temperature dependence is found. The simultaneous tunnelling of 3,5,7 etc. electrons and quantum interference effects are predicted. (author)

  7. Music hall Markneukirchen; Musikhalle in Markneukirchen

    Energy Technology Data Exchange (ETDEWEB)



    The article presents the new building of the music hall Markneukirchen. From the planned use of the building result very high demands on the ventilation system in order to keep to a sound power level of less than 30 dB(A) in the hall. The building services are dealt with using numerous flowsheets and diagrams: Heat supply, ventilation system, sanitary system, building management, instrumentation and control, electric and lighting systems. (BWI) [Deutsch] Der vorliegende Beitrag stellt den Neubau der Musikhalle Markneukirchen vor. Durch das Nutzungskonzept ergeben sich fuer die Einhaltung eines Schalleistungspegels von weniger als 30 dB(A) im Saalbereich an die Lueftungsanlage sehr hohe Ansprueche. Es werden die raumlufttechnischen Anlagen anhand zahlreicher Flussbilder und Abbildungen vorgestellt: Waermeversorgung, Lueftungstechnik, Sanitaertechnik, Gebaeudeleit- und MSR-Technik, Elektro- und Lichttechnik. (BWI)

  8. Type of Student Residence as a Factor in College Students' Alcohol Consumption and Social Normative Perceptions regarding Alcohol Use (United States)

    Page, Randy M.; O'Hegarty, Michelle


    The purpose of this study was to determine alcohol use (particularly heavy drinking) and social normative estimations of alcohol use according to student residence (fraternity, sorority, residence hall, or apartment complex). To achieve this purpose, a survey was conducted in all 34 sections of a general education core English class at a…

  9. Acoustics in rock and pop music halls

    DEFF Research Database (Denmark)

    Adelman-Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders Christian


    The existing body of literature regarding the acoustic design of concert halls has focused almost exclusively on classical music, although there are many more performances of rhythmic music, including rock and pop. Objective measurements were made of the acoustics of twenty rock music venues...... frequency sounds are typically highly amplified, they play an important role in the subjective ratings and the 63-Hz-band must be included in objective measurements and recommendations....

  10. SPS beam to the West Hall

    CERN Multimedia

    CERN PhotoLab


    One of the two target stations feeding the West Hall (see Annual Report 1976). After the proton beam was split into three branches, the outer two were directed on to targets in the cast iron shielding box, the centre one passing through the box to another target station downstream. Five different targets could be put in each beam, controlled by the mechanism seen on top.

  11. SERVIR Town Hall - Connecting Space to Village (United States)

    Limaye, Ashutosh S.; Searby, Nancy D.; Irwin, Daniel; Albers, Cerese


    SERVIR, a joint NASA-USAID project, strives to improve environmental decision making through the use of Earth observations, models, and geospatial technology innovations. SERVIR connects these assets with the needs of end users in Mesoamerica, East Africa, and Hindu Kush-Himalaya regions. This Town Hall meeting will engage the AGU community by exploring examples of connecting Space to Village with SERVIR science applications.

  12. Viscoelastic-electromagnetism and Hall viscosity


    Hidaka, Yoshimasa; Hirono, Yuji; Kimura, Taro; Minami, Yuki


    We introduce a kind of electromagnetism, which we call viscoelastic-electromagnetism, to investigate viscoelastic transport phenomena. It is shown that Cartan's formalism of general relativity is essential for viscoelastic theory, and then the corresponding electric and magnetic fields are regarded as a velocity gradient and a Burgers vector density, respectively. As an application of this formalism, the Streda formula for the Hall viscosity is obtained.

  13. Acoustics in rock and pop music halls

    DEFF Research Database (Denmark)

    Adelman-Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders Christian


    The existing body of literature regarding the acoustic design of concert halls has focused almost exclusively on classical music, although there are many more performances of rhythmic music, including rock and pop. Objective measurements were made of the acoustics of twenty rock music venues in D...... frequency sounds are typically highly amplified, they play an important role in the subjective ratings and the 63-Hz-band must be included in objective measurements and recommendations....

  14. Industrial steel hall with bridge grane


    Jurejevčič, Nejc


    In introduction this diploma thesis describes all main characteristics of (single block)? industrial steel hall with bridge crane. Load arrangement on the supporting structure which covers general actions (snow load and wind action), self-weight and dynamic load of bridge crane was designed with moment resisting frame in transverse direction and frame with concentric diagonal bracing in longitudinual direction. Actions induced by crane bridge was considered in design of runway beam. Steel hal...

  15. Plasma pressure tensor effects on reconnection: Hybrid and Hall-magnetohydrodynamics simulations

    International Nuclear Information System (INIS)

    Yin Lin; Winske, Dan


    Collisionless reconnection is studied using two-dimensional (2-D) hybrid (particle ions, massless fluid electrons) and Hall-magnetohydrodynamics (Hall-MHD) simulations. Both use the full electron pressure tensor instead of a localized resistivity in Ohm's law to initiate reconnection; an initial perturbation or boundary driving to the equilibrium is used. The initial configurations include one-dimensional (1-D) and 2-D current sheets both with and without a guide field. Electron dynamics from the two calculations are compared, and overall agreement is found between the calculations in both reconnection rate and global configuration [L. Yin et al., J. Geophys. Res. 106, 10761 (2001)]. It is shown that the electron drifts in the small-transverse-scale fields near the X point cause the electron motion to decouple from the ion motion, and that reconnection occurs due to electron viscous effects contained in the off-diagonal terms of the electron pressure tensor. Comparing the hybrid and Hall-MHD simulations shows that effects of the off-diagonal terms in the ion pressure tensor, i.e., the ion gyro-radius effects, are necessary in order to model correctly the ion out-of-plane motion. It is shown that these effects can be modeled efficiently in a particle Hall-MHD simulation in which particle ions are used in a predictor/corrector manner to implement ion gyro-radius corrections [L. Yin et al., Phys. Plasmas 9, 2575 (2002)]. For modeling reconnection in large systems, a new integrated approach is examined in which Hall-MHD calculations using a full electron pressure tensor model is embedded inside a MHD simulation. The embedded simulation of current sheet thinning and reconnection dynamics in a realistic 2-D magnetotail equilibrium exhibits smooth transitions of plasma and field quantities between the two regions, with small-scale physics represented well in the compressed current sheet and in the near-X-point region

  16. Anode Fall Formation in a Hall Thruster

    International Nuclear Information System (INIS)

    Dorf, Leonid A.; Raitses, Yevgeny F.; Smirnov, Artem N.; Fisch, Nathaniel J.


    As was reported in our previous work, accurate, nondisturbing near-anode measurements of the plasma density, electron temperature, and plasma potential performed with biased and emissive probes allowed the first experimental identification of both electron-repelling (negative anode fall) and electron-attracting (positive anode fall) anode sheaths in Hall thrusters. An interesting new phenomenon revealed by the probe measurements is that the anode fall changes from positive to negative upon removal of the dielectric coating, which appears on the anode surface during the course of Hall thruster operation. As reported in the present work, energy dispersion spectroscopy analysis of the chemical composition of the anode dielectric coating indicates that the coating layer consists essentially of an oxide of the anode material (stainless steel). However, it is still unclear how oxygen gets into the thruster channel. Most importantly, possible mechanisms of anode fall formation in a Hall thruster with a clean and a coated anodes are analyzed in this work; practical implication of understanding the general structure of the electron-attracting anode sheath in the case of a coated anode is also discussed

  17. Hall viscosity: A link between quantum Hall systems, plasmas and liquid crystals

    Energy Technology Data Exchange (ETDEWEB)

    Lingam, Manasvi, E-mail:


    In this Letter, the assumption of two simple postulates is shown to give rise to a Hall viscosity term via an action principle formulation. The rationale behind the two postulates is clearly delineated, and the connections to an intrinsic angular momentum are emphasized. By employing this methodology, it is shown that Hall viscosity appears in a wide range of fields, and the interconnectedness of quantum Hall systems, plasmas and nematic liquid crystals is hypothesized. Potential avenues for experimental and theoretical work arising from this cross-fertilization are also indicated. - Highlights: • Connections between simple 2D fluid models in different fields of physics presented. • Structure emerges via varied physical mechanisms driven by internal angular momentum. • Properties of these models such as Casimirs, equilibria and stability are analyzed.

  18. Shareholders' agreements in Denmark

    DEFF Research Database (Denmark)

    Werlauff, Erik


    The article warns that with effect from 1 March 2010, the new Danish Companies Act (on public and private limited companies) has seriously weakened the effect of shareholders’ agreements which have been entered into on Danish companies. These agreements (in the act’s new terminology: “owners...

  19. Competition for Assistance Agreements (United States)

    It is EPA policy to promote competition in the award of assistance agreements to the maximum extent practicable.When assistance agreements are awarded competitively, it is EPA policy that the competitive process be fair and open & that no applicant receive

  20. Habitat Restoration/Enhancement Fort Hall Reservation : 2008 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Osborne, Hunter [Shoshone Bannock Tribes


    Habitat enhancement, protection and monitoring were the focus of the Resident Fisheries Program during 2008. Enhancement and protection included sloping, fencing and planting wetlands plugs at sites on Spring Creek (Head-waters). Many previously constructed instream structures (rock barbs and wing dams) were repaired throughout the Fort Hall Indian Reservation (Reservation). Physical sampling during 2008 included sediment and depth measurements (SADMS) in Spring Creek at the Car Removal site. SADMS, used to track changes in channel morphology and specifically track movements of silt through Bottoms stream systems were completed for 5 strata on Spring Creek. Water temperature and chemistry were monitored monthly on Spring Creek, Clear Creek, Diggie Creek, and Portneuf (Jimmy Drinks) and Blackfoot rivers. Fish population densities and biomass were sampled in five reservation streams which included nine sites. Sampling protocols were identical to methods used in past years. Numbers of fish in Spring Creek series remained relatively low, however, there was an increase of biomass overall since 1993. Salmonid fry densities were monitored near Broncho Bridge and were similar to 2006, and 2007, however, as in years past, high densities of macrophytes make it very difficult to see fry in addition to lack of field technicians. Mean catch rate by anglers on Bottoms streams stayed the same as 2007 at 1.5/hr. Numbers of fish larger than 18-inches caught by anglers increased from 2007 at .20 to .26/hr.

  1. Residency Allocation Database (United States)

    Department of Veterans Affairs — The Residency Allocation Database is used to determine allocation of funds for residency programs offered by Veterans Affairs Medical Centers (VAMCs). Information...

  2. Commemorative Symposium on the Hall Effect and its Applications

    CERN Document Server

    Westgate, C


    In 1879, while a graduate student under Henry Rowland at the Physics Department of The Johns Hopkins University, Edwin Herbert Hall discovered what is now universally known as the Hall effect. A symposium was held at The Johns Hopkins University on November 13, 1979 to commemorate the lOOth anniversary of the discovery. Over 170 participants attended the symposium which included eleven in­ vited lectures and three speeches during the luncheon. During the past one hundred years, we have witnessed ever ex­ panding activities in the field of the Hall effect. The Hall effect is now an indispensable tool in the studies of many branches of condensed matter physics, especially in metals, semiconductors, and magnetic solids. Various components (over 200 million!) that utilize the Hall effect have been successfully incorporated into such devices as keyboards, automobile ignitions, gaussmeters, and satellites. This volume attempts to capture the important aspects of the Hall effect and its applications. It includes t...

  3. Nonlinearity in the effect of an inhomogeneous Hall angle (United States)

    Koon, Daniel W.


    The differential equation for the electric potential in a conducting material with an inhomogeneous Hall angle is extended to the large-field limit. This equation is solved for a square specimen, using a successive over-relaxation [SOR] technique for matrices of up to 101x101 size, and the Hall weighting function -- the effect of local pointlike perturbations on the measured Hall angle -- is calculated as both the unperturbed Hall angle, θH, and the perturbation, δθH, exceed the linear, small angle limit. Preliminary results show that the Hall angle varies by no more than 5% if both | θH |<1 and | δθH |<1. Thus, previously calculated results for the Hall weighting function can be used for most materials in all but the most extreme magnetic fields.

  4. Basic Instrumentation for Hall A at Jefferson Jab

    International Nuclear Information System (INIS)

    The Jefferson Lab Hall A Collaboration


    The instrumentation in Hall A at the JLab was designed to study electro- and photo-induced reactions at very high luminosity and good momentum and angular resolution for at least one of the reaction products. A collaboration of approximately 50 institutions from all over the world has actively contributed and participated in the design, construction and commissioning of the Hall A instrumentation. The basic Hall A equipment is described herein

  5. The Sicomines Agreement

    DEFF Research Database (Denmark)

    Jansson, Johanna

    of the global political economy have shifted, and that China’s position as a foreign policy actor is now consolidated. Continuity, since the 2009 amendment of the agreement, which came about partly as a result of China’s ambitions to take up an active role in the International Monetary Fund (IMF......, the investment into the DRC’s mining sector is in itself beneficial for the country, and the renegotiation of the agreement was positive in the sense that the Congolese state guarantee for the mining component was removed. However, the question of whether the Sicomines agreement is a good deal for the DRC...

  6. Precision of single-engage micro Hall effect measurements

    DEFF Research Database (Denmark)

    Henrichsen, Henrik Hartmann; Hansen, Ole; Kjær, Daniel


    Recently a novel microscale Hall effect measurement technique has been developed to extract sheet resistance (RS), Hall sheet carrier density (NHS) and Hall mobility (μH) from collinear micro 4-point probe measurements in the vicinity of an insulating boundary [1]. The technique measures in less......]. In this study we calculate the measurement error on RS, NHS and μH resulting from electrode position errors, probe placement, sample size and Hall signal magnitude. We show the relationship between measurement precision and electrode pitch, which is important when down-scaling the micro 4-point probe to fit...

  7. High Efficiency Hall Thruster Discharge Power Converter Project (United States)

    National Aeronautics and Space Administration — Busek leveraged previous, internally sponsored, high power, Hall thruster discharge converter development which allowed it to design, build, and test new printed...

  8. Hall Sensor Output Signal Fault-Detection & Safety Implementation Logic

    Directory of Open Access Journals (Sweden)

    Lee SangHun


    Full Text Available Recently BLDC motors have been popular in various industrial applications and electric mobility. Recently BLDC motors have been popular in various industrial applications and electric mobility. In most brushless direct current (BLDC motor drives, there are three hall sensors as a position reference. Low resolution hall effect sensor is popularly used to estimate the rotor position because of its good comprehensive performance such as low cost, high reliability and sufficient precision. Various possible faults may happen in a hall effect sensor. This paper presents a fault-tolerant operation method that allows the control of a BLDC motor with one faulty hall sensor and presents the hall sensor output fault-tolerant control strategy. The situations considered are when the output from a hall sensor stays continuously at low or high levels, or a short-time pulse appears on a hall sensor signal. For fault detection, identification of a faulty signal and generating a substitute signal, this method only needs the information from the hall sensors. There are a few research work on hall effect sensor failure of BLDC motor. The conventional fault diagnosis methods are signal analysis, model based analysis and knowledge based analysis. The proposed method is signal based analysis using a compensation signal for reconfiguration and therefore fault diagnosis can be fast. The proposed method is validated to execute the simulation using PSIM.

  9. Neutronic design of MYRRHA reactor hall shielding

    Directory of Open Access Journals (Sweden)

    Celik Yurdunaz


    Full Text Available The lateral shielding of a 600 MeV proton linear accelerator beam line in the MYRRHA reactor hall has been assessed using neutronic calculations by the MCNPX code complemented with analytical predictions. Continuous beam losses were considered to define the required shielding thickness that meets the requirements for the dose rate limits. Required shielding thicknesses were investigated from the viewpoint of accidental full beam loss as well as beam loss on collimator. The results confirm that the required shielding thicknesses are highly sensitive to the spatial shape of the beam and strongly divergent beam losses. Therefore shielding barrier should be designed according to the more conservative assumptions.

  10. Fractional quantization and the quantum hall effect

    International Nuclear Information System (INIS)

    Guerrero, J.; Calixto, M.; Aldaya, V.


    Quantization with constrains is considered in a group-theoretical framework, providing a precise characterization of the set of good operators, i.e., those preserving the constrained Hilbert space, in terms of the representation of the subgroup of constraints. This machinery is applied to the quantization of the torus as symplectic manifold, obtaining that fractional quantum numbers are permitted, provided that we allow for vector valued representations. The good operators turn out to be the Wilson loops and, for certain representations of the subgroup of constraints, the modular transformations. These results are applied to the Fractional Quantum Hall Effect, where interesting implications are derived

  11. Optically induced Hall effect in semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Idrish Miah, M; Gray, E Mac A, E-mail: [Nanoscale Science and Technology Centre, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)


    We describe an experiment which investigates the effect of a longitudinal electric field on the spin-polarized carriers generated by a circularly polarized light in semiconductors. Our experiment observes the effect as a Hall voltage resulting from nonequilibrium magnetization induced by the spin-carrier electrons accumulating at the transverse boundaries of the sample as a result of asymmetries in scattering for spin-up and spin-down electrons in the presence of spin-orbit interaction. It is found that the effect depends on the longitudinal electric field and doping density as well as on temperature. The results are presented by discussing the dominant spin relaxation mechanisms in semiconductors.

  12. Hall conductivity for two dimensional magnetic systems

    International Nuclear Information System (INIS)

    Desbois, J.; Ouvry, S.; Texier, C.


    A Kubo inspired formalism is proposed to compute the longitudinal and transverse dynamical conductivities of an electron in a plane (or a gas of electrons at zero temperature) coupled to the potential vector of an external local magnetic field, with the additional coupling of the spin degree of freedom of the electron to the local magnetic field (Pauli Hamiltonian). As an example, the homogeneous magnetic field Hall conductivity is rederived. The case of the vortex at the origin is worked out in detail. A perturbative analysis is proposed for the conductivity in the random magnetic impurity problem (Poissonian vortices in the plane). (author)

  13. Chiral heat transport in driven quantum Hall and quantum spin Hall edge states (United States)

    Arrachea, Liliana; Fradkin, Eduardo


    We consider a model for an edge state of electronic systems in the quantum Hall regime with filling ν=1 and in the quantum spin Hall regime. In both cases, the system is in contact with two reservoirs by tunneling at point contacts. Both systems are locally driven by applying an ac voltage in one of the contacts. By weakly coupling them to a third reservoir, the transport of the generated heat is studied in two different ways: (i) when the third reservoir acts as a thermometer, the local temperature is sensed and (ii) when the third reservoir acts as a voltage probe, the time-dependent local voltage is sensed. Our results indicate a chiral propagation of the heat along the edge in the quantum Hall and in the quantum spin Hall cases (if the injected electrons are spin polarized). We also show that a analogous picture is obtained if instead of heating by ac driving the system is put in contact to a stationary reservoir at a higher temperature. In both cases, the temperature profile shows that the electrons along the edge thermalize with the closest “upstream” reservoir.

  14. Trade Agreements PTI (United States)

    Department of Homeland Security — The objective of the Trade Agreements PTI is to advance CBP’s mission by working with internal and external stakeholders to facilitate legitimate trade and address...

  15. Australia's nuclear safeguards agreements

    International Nuclear Information System (INIS)


    This is a compilation of the bilateral agreements concluded by Australia concerning co-operation in the peaceful uses of nuclear energy. The publication also includes the agreement with the International Atomic Energy Agency (IAEA) for the application of safeguards in connection with the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) and the agreement with EURATOM on transfers of nuclear materials from Australia to the European Atomic Energy Community. The other agreements were concluded with the following countries: Canada, Egypt, Finland, France, Japan, Republic of Korea, Philippines, Singapore, Sweden, Switzerland, USSR, United Kingdom and United States. They concern transfers of nuclear materials and equipment, research and development, exchange of information, etc. All contain provisions on safeguards, physical protection and restrictions on exports to third countries [fr

  16. Watershed Management Partnership Agreement (United States)

    On November 19, 2004, the U.S. Environmental Protection Agency and the U.S. Army Corps of Engineers signed the Watershed Management Partnership Agreement to promote watershed health, economic sustainability and community vitality through effective manageme

  17. International Fisheries Agreements

    DEFF Research Database (Denmark)

    Pintassilgo, Pedro; Kronbak, Lone Grønbæk; Lindroos, Marko


    This paper surveys the application of game theory to the economic analysis of international fisheries agreements. The relevance of this study comes not only from the existence of a vast literature on the topic but especially from the specific features of these agreements. The emphasis of the survey...... is on coalition games, an approach that has become prominent in the fisheries economics literature over the last decade. It is shown that coalition games were first applied to international fisheries agreements in the late 1990s addressing cooperative issues under the framework of characteristic function games....... Then, progres- sively, this cooperative approach was combined with non-cooperative elements such as the stability analysis of the agreements. Finally, partition function games, which model coalition formation endogenously, were introduced and became the standard approach to study the formation...

  18. The Quantum Hall Effect: after 20 years still a challenge for theory and experiment (United States)

    Landwehr, G.

    A short review of the pre-history of the discovery of the QHE is given. It is shown that the effect could have been recognized several years earlier. The subsequent development is briefly sketched and the importance of the availability of high quality heterostructures is emphasized. It is shown that modulation doped HgTe/(CdHg) Te single quantum wells are promising for future research on the integer quantum Hall effect. The definition of the von Klitzing constant: 25812,807 ω by international agreement put resistance measurements on a new and reliable basis.

  19. Spectral Analysis of Non-ideal MRI Modes: The Effect of Hall Diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Mohandas, Gopakumar; Pessah, Martin E., E-mail:, E-mail: [Niels Bohr International Academy, Niels Bohr Institute, Blegdamsvej 17, DK-2100, Copenhagen Ø (Denmark)


    The effect of magnetic field diffusion on the stability of accretion disks is a problem that has attracted considerable interest of late. In particular, the Hall effect has the potential to bring about remarkable changes in the dynamical behavior of disks that are without parallel. In this paper, we conduct a systematic examination of the linear eigenmodes in a weakly magnetized differentially rotating gas with a special focus on Hall diffusion. We first develop a geometrical representation of the eigenmodes and provide a detailed quantitative description of the polarization properties of the oscillatory modes under the combined influence of the Coriolis and Hall effects. We also analyze the effects of magnetic diffusion on the structure of the unstable modes and derive analytical expressions for the kinetic and magnetic stresses and energy densities associated with the non-ideal magnetorotational instability (MRI). Our analysis explicitly demonstrates that, if the dissipative effects are relatively weak, the kinetic stresses and energies make up the dominant contribution to the total stress and energy density when the equilibrium angular momentum and magnetic field vectors are anti-parallel. This is in sharp contrast to what is observed in the case of the ideal or dissipative MRI. We conduct shearing box simulations and find very good agreement with the results derived from linear theory. Because the modes under consideration are also exact solutions of the nonlinear equations, the unconventional nature of the kinetic and magnetic stresses may have significant implications for the nonlinear evolution in some regions of protoplanetary disks.

  20. Cylindrical Hall Thrusters with Permanent Magnets

    International Nuclear Information System (INIS)

    Raitses, Yevgeny; Merino, Enrique; Fisch, Nathaniel J.


    The use of permanent magnets instead of electromagnet coils for low power Hall thrusters can offer a significant reduction of both the total electric power consumption and the thruster mass. Two permanent magnet versions of the miniaturized cylindrical Hall thruster (CHT) of different overall dimensions were operated in the power range of 50W-300 W. The discharge and plasma plume measurements revealed that the CHT thrusters with permanent magnets and electromagnet coils operate rather differently. In particular, the angular ion current density distribution from the permanent magnet thrusters has an unusual halo shape, with a majority of high energy ions flowing at large angles with respect to the thruster centerline. Differences in the magnetic field topology outside the thruster channel and in the vicinity of the channel exit are likely responsible for the differences in the plume characteristics measured for the CHTs with electromagnets and permanent magnets. It is shown that the presence of the reversing-direction or cusp-type magnetic field configuration inside the thruster channel without a strong axial magnetic field outside the thruster channel does not lead to the halo plasma plume from the CHT.

  1. Planar Hall Effect in Magnetic Conducting Oxides (United States)

    Akouala, Christer Rajiv

    Magnetic semiconductors are of interest for use in non-volatile memory device read heads, magnetoresistive sensors, and other spintronic devices. Research in this area has mostly focused on generating magnetic semiconductors by doping non-magnetic semiconductors with magnetic ions. This work has instead taken advantage of the defectinduced magnetism in several semiconducting oxides. The planar Hall effect (PHE) is a phenomenon that can be used for characterizing magnetic semiconductors. Along with the anisotropic magnetoresistance (AMR), PHE has the potential to provide insight into the mechanism for magnetic behavior in magnetic conducting oxide thin films that are undoped. PHE has therefore been studied in undoped ZnO, SnO2, CdO, and CuO using magnetotransport and magnetometry techniques. The measurements included both AMR and PHE taken at various temperatures from 300 to 4.2K in a Quantum Design Physical Property Measurement System (QD-PPMS) and in a custom-built magnetotransport set-up. Complementary measurements include XRD, and resistivity measurements. Resistivity vs. temperature, Hall effect, and magnetoresistance measurements were performed in the PPMS. Magnetic hysteresis and magnetization vs. temperature were acquired using a Quantum Design Magnetic Properties Measurement System (QD-MPMS).

  2. Undulator Hall Air Temperature Fault Scenarios

    International Nuclear Information System (INIS)

    Sevilla, J.


    Recent experience indicates that the LCLS undulator segments must not, at any time following tuning, be allowed to change temperature by more than about ±2.5 C or the magnetic center will irreversibly shift outside of acceptable tolerances. This vulnerability raises a concern that under fault conditions the ambient temperature in the Undulator Hall might go outside of the safe range and potentially could require removal and retuning of all the segments. In this note we estimate changes that can be expected in the Undulator Hall air temperature for three fault scenarios: (1) System-wide power failure; (2) Heating Ventilation and Air Conditioning (HVAC) system shutdown; and (3) HVAC system temperature regulation fault. We find that for either a system-wide power failure or an HVAC system shutdown (with the technical equipment left on), the short-term temperature changes of the air would be modest due to the ability of the walls and floor to act as a heat ballast. No action would be needed to protect the undulator system in the event of a system-wide power failure. Some action to adjust the heat balance, in the case of the HVAC power failure with the equipment left on, might be desirable but is not required. On the other hand, a temperature regulation failure of the HVAC system can quickly cause large excursions in air temperature and prompt action would be required to avoid damage to the undulator system.

  3. Quantum Hall samples prepared by helium-ion implantation

    International Nuclear Information System (INIS)

    Bruus, H.; Lindelof, P.E.; Veje, E.


    We have produced GaAs/GaAlAs heterostructure based quantum Hall samples with a wide range of electron mobilities using ion implantation. The purpose has been to optimize the samples for use in metrology. We have in particular studied the critical current and the non-ohmic behavior of our samples in the vicinity of a quantum Hall plateau. (orig.)

  4. Magnetoresistance in quantum Hall metals due to Pancharatnam ...

    Indian Academy of Sciences (India)

    topological insulators [10,11] and quantum Hall metals [12–21] are the other major solid- state systems that currently need proper and consistent formulations to understand their electronic properties, regardless of whether these systems have the potential for future technological marvels. Here, we shall derive the trial Hall ...

  5. Mary E. Hall: Dawn of the Professional School Librarian (United States)

    Alto, Teresa


    A century ago, a woman named Mary E. Hall convinced school leaders of the need for the professional school librarian--a librarian who cultivated a love of reading, academic achievement, and independent learning skills. After graduating from New York City's Pratt Institute Library School in 1895, Hall developed her vision for the high school…

  6. Role of the Hall Effect on the Magnetorotational Instability (United States)

    Bejarano, Cecilia; Gómez, Daniel

    Within the framework of magnetohydrodynamics, the Hall effect might become significant either in fully ionized low density plasmas or in cold plasmas with a low ionization fraction. We address the role of the Hall current in the development of the magnetorotational instability. The instability criterion and the instability growth rate are derived from a one-dimensional model.

  7. Pair spectrometer hodoscope for Hall D at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, F.; Hutton, C.; Sitnikov, A. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Somov, A., E-mail: [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Somov, S.; Tolstukhin, I. [National Research Nuclear University MEPhI, Moscow (Russian Federation)


    We present the design of the pair spectrometer hodoscope fabricated at Jefferson Lab and installed in the experimental Hall D. The hodoscope consists of thin scintillator tiles; the light from each tile is collected using wave-length shifting fibers and detected using a Hamamatsu silicon photomultiplier. Light collection was measured using relativistic electrons produced in the tagger area of the experimental Hall B.

  8. Critical current in the Integral Quantum Hall Effect

    International Nuclear Information System (INIS)

    Kostadinov, I.Z.


    A multiparticle theory of the Integral Quantum Hall Effect (IQHE) was constructed operating with pairs wave function as an order parameter. The IQHE is described with bosonic macroscopic states while the fractional QHE with fermionic ones. The calculation of the critical current and Hall conductivity temperature dependence is presented. (author)

  9. Stuart Hall on Racism and the Importance of Diasporic Thinking (United States)

    Rizvi, Fazal


    In this article, I want to show how my initial encounter with the work of Stuart Hall was grounded in my reading of the later philosophy of Ludwig Wittgenstein, and was shaped by my interest in understanding the nature of racism across the three countries in which I had lived. Over the years, Hall's various writings have helped me to make sense of…

  10. Useful Pedagogical Applications of the Classical Hall Effect (United States)

    Houari, Ahmed


    One of the most known phenomena in physics is the Hall effect. This is mainly due to its simplicity and to the wide range of its theoretical and practical applications. To complete the pedagogical utility of the Hall effect in physics teaching, I will apply it here to determine the Faraday constant as a fundamental physical number and the number…

  11. Bulk Versus Edge in the Quantum Hall Effect


    Kao, Y. -C.; Lee, D. -H.


    The manifestation of the bulk quantum Hall effect on edge is the chiral anomaly. The chiral anomaly {\\it is} the underlying principle of the ``edge approach'' of quantum Hall effect. In that approach, $\\sxy$ should not be taken as the conductance derived from the space-local current-current correlation function of the pure one-dimensional edge problem.

  12. Residency training program: Perceptions of residents

    African Journals Online (AJOL)

    This study was carried out to ascertain the perception of the residency ... the time of the study. Analysis of the respondents showed similar findings for both senior and junior levels of training. Discussion. The introduction of the residency training program .... Overseas training/ attachment should be re-introduced. 12. (10.1).

  13. Unconventional quantum Hall effect in Floquet topological insulators

    KAUST Repository

    Tahir, M.


    We study an unconventional quantum Hall effect for the surface states of ultrathin Floquet topological insulators in a perpendicular magnetic field. The resulting band structure is modified by photon dressing and the topological property is governed by the low-energy dynamics of a single surface. An exchange of symmetric and antisymmetric surface states occurs by reversing the lights polarization. We find a novel quantum Hall state in which the zeroth Landau level undergoes a phase transition from a trivial insulator state, with Hall conductivity αyx = 0 at zero Fermi energy, to a Hall insulator state with αyx = e2/2h. These findings open new possibilities for experimentally realizing nontrivial quantum states and unusual quantum Hall plateaus at (±1/2,±3/2,±5/2, ...)e2/h. © 2016 IOP Publishing Ltd Printed in the UK.

  14. Accurate micro Hall effect measurements on scribe line pads

    DEFF Research Database (Denmark)

    Østerberg, Frederik Westergaard; Petersen, Dirch Hjorth; Wang, Fei


    be extracted from micro four-point measurements performed on a rectangular pad. The dimension of the investigated pad is 400 × 430 ¿m2, and the probe pitches range from 20 ¿m to 50 ¿m. The Monte Carlo method is used to find the optimal way to perform the Hall measurement and extract Hall mobility most......Hall mobility and sheet carrier density are important parameters to monitor in advanced semiconductor production. If micro Hall effect measurements are done on small pads in scribe lines, these parameters may be measured without using valuable test wafers. We report how Hall mobility can...... accurate in less than a minute. Measurements are performed on shallow trench isolation patterned silicon wafers to verify the results from the Monte Carlo method....

  15. A Novel Hall Effect Sensor Using Elaborate Offset Cancellation Method

    Directory of Open Access Journals (Sweden)

    Vlassis N. Petoussis


    Full Text Available The Hall effect is caused by a traverse force that is formed in the electrons or holes of metal element or semiconductor when are polarized by current source and simultaneously all the system it is found vertical in external magnetic field. Result is finally the production of difference of potential (Hall voltage in address vertical in that of current and magnetic field directions. In the present work is presented a new Hall sensor exploiting the former operation. In combination with his pioneering form and using dynamic spinning current technique with an elaborate sequence, it leads to satisfactory results of produced Hall voltage with small noise in a presence of external magnetic field. Anyone can see both the spinning current and anti-Hall technique in the same sensor simultaneously.

  16. EL CROWN HALL. CONTEXTO Y PROYECTO / The Crown Hall. Context and project

    Directory of Open Access Journals (Sweden)

    José Santatecla Fayós


    Full Text Available RESUMEN El artículo enmarca el edificio del Crown Hall en el contexto docente y arquitectónico de Mies van der Rohe. Revisa sus inicios en la Bauhaus con su primera intervención en un espacio docente para la Bauhaus de Berlín en 1932, así como su marcha a Estados Unidos, los planteamientos arquitectónicos del campus del IIT y el proyecto del Crown Hall. El texto incide en el estudio del proceso proyectual del Crown Hall analizando la evolución de su concepción arquitectónica a través de las diferentes versiones del proyecto. Se constata la transición desde los primeros planteamientos arquitectónicos de los edificios del campus del IIT proyectados por Mies hacia el planteamiento del gran espacio unitario del Crown Hall. Este proyecto se puede entender desde la creciente importancia de la estructura, la claridad constructiva y el manejo del acero y vidrio como únicos materiales de la imagen del edificio y el carácter flexible y unitario del espacio. Finalmente se hace referencia al concepto del “espacio universal” en la arquitectura de Mies, como un concepto abstracto que supera los de flexibilidad de uso o unidad espacial, insinuando, a modo de reflexión, las principales variables que definirían el espacio universal miesiano. SUMMARY The article showcases the Crown Hall building in the educational and architectural context of Mies van der Rohe. It reviews his beginnings in the Bauhaus with his first intervention in an educational space for the Bauhaus of Berlin in 1932, as well as his sojourn to the United States, and the architectural approaches to the IIT campus and the Crown Hall project. The text touches on the study of the planning process for the Crown Hall, analysing the evolution of its architectural conception, through the different versions of the project. The article covers the transition from the first architectural approaches for the IIT campus buildings, planned by Mies, to the approach of the large unitary space

  17. Concept of Operating Indoor Skiing Halls with

    DEFF Research Database (Denmark)

    Paul, Joachim


    Indoor skiing halls are conventionally operated at low temperatures and with either crushed ice as snow substitute or snow made from freezing water in cold air. Both systems have a high energy demand for air cooling, floor freezing and consequently snow harvest. At the same time the snow at the top...... floor cooling/freezing and insulation become obsolete, significant savings in piping and building costs can be achieved. Due to the much higher evaporating temperature for the refrigeration system, the energy demand is kept low. Since the same equipment is used for both snowmaking and air cooling......, the running time of the equipment is high, resulting in a better economy. Using Binary Snow, with its unique qualities such as fluffy, crisp, white and ¿ since made daily ¿ "fresh and hygienic", offers great advantages in operating costs, investment costs and quality....

  18. Magnetic circuit for hall effect plasma accelerator (United States)

    Manzella, David H. (Inventor); Jacobson, David T. (Inventor); Jankovsky, Robert S. (Inventor); Hofer, Richard (Inventor); Peterson, Peter (Inventor)


    A Hall effect plasma accelerator includes inner and outer electromagnets, circumferentially surrounding the inner electromagnet along a thruster centerline axis and separated therefrom, inner and outer magnetic conductors, in physical connection with their respective inner and outer electromagnets, with the inner magnetic conductor having a mostly circular shape and the outer magnetic conductor having a mostly annular shape, a discharge chamber, located between the inner and outer magnetic conductors, a magnetically conducting back plate, in magnetic contact with the inner and outer magnetic conductors, and a combined anode electrode/gaseous propellant distributor, located at a bottom portion of the discharge chamber. The inner and outer electromagnets, the inner and outer magnetic conductors and the magnetically conducting back plate form a magnetic circuit that produces a magnetic field that is largely axial and radially symmetric with respect to the thruster centerline.

  19. Frequency spectrum of Calder Hall reactor noise

    International Nuclear Information System (INIS)

    Cummins, J.D.


    The frequency spectrum of the noise power of Calder Hall reactor No. 1 has been obtained by analysing a tape recording of the backed off power. The root mean square noise power due to all frequencies above 0.001 cycles per second was found to be 0.13%. The noise power for this reactor, is due mainly to modulations of the power level by reactivity variations caused in turn by gas temperature changes. These gas temperature changes are caused by a Cyclic variation in the feedwater regulator to the heat exchanger. The apparatus and method used to determine the noise power are described in this memorandum. It is shown that for frequencies in the range 0.001 to 0.030 cycles per second the noise spectrum falls at 60 decibels per decade of frequency. (author)

  20. Numerical investigation of a Hall thruster plasma

    International Nuclear Information System (INIS)

    Roy, Subrata; Pandey, B.P.


    The dynamics of the Hall thruster is investigated numerically in the framework of a one-dimensional, multifluid macroscopic description of a partially ionized xenon plasma using finite element formulation. The model includes neutral dynamics, inelastic processes, and plasma-wall interaction. Owing to disparate temporal scales, ions and neutrals have been described by set of time-dependent equations, while electrons are considered in steady state. Based on the experimental observations, a third order polynomial in electron temperature is used to calculate ionization rate. The results show that in the acceleration channel the increase in the ion number density is related to the decrease in the neutral number density. The electron and ion velocity profiles are consistent with the imposed electric field. The electron temperature remains uniform for nearly two-thirds of the channel; then sharply increases to a peak before dropping slightly at the exit. This is consistent with the predicted electron gyration velocity distribution

  1. Gauge Physics of Spin Hall Effect (United States)

    Tan, Seng Ghee; Jalil, Mansoor B. A.; Ho, Cong Son; Siu, Zhuobin; Murakami, Shuichi


    Spin Hall effect (SHE) has been discussed in the context of Kubo formulation, geometric physics, spin orbit force, and numerous semi-classical treatments. It can be confusing if the different pictures have partial or overlapping claims of contribution to the SHE. In this article, we present a gauge-theoretic, time-momentum elucidation, which provides a general SHE equation of motion, that unifies under one theoretical framework, all contributions of SHE conductivity due to the kinetic, the spin orbit force (Yang-Mills), and the geometric (Murakami-Fujita) effects. Our work puts right an ambiguity surrounding previously partial treatments involving the Kubo, semiclassical, Berry curvatures, or the spin orbit force. Our full treatment shows the Rashba 2DEG SHE conductivity to be instead of -, and Rashba heavy hole instead of -. This renewed treatment suggests a need to re-derive and re-calculate previously studied SHE conductivity.

  2. Fractional quantum Hall effect in optical lattices

    International Nuclear Information System (INIS)

    Hafezi, M.; Demler, E.; Lukin, M. D.; Soerensen, A. S.


    We analyze a recently proposed method to create fractional quantum Hall (FQH) states of atoms confined in optical lattices [A. Soerensen et al., Phys. Rev. Lett. 94, 086803 (2005)]. Extending the previous work, we investigate conditions under which the FQH effect can be achieved for bosons on a lattice with an effective magnetic field and finite on-site interaction. Furthermore, we characterize the ground state in such systems by calculating Chern numbers which can provide direct signatures of topological order and explore regimes where the characterization in terms of wave-function overlap fails. We also discuss various issues which are relevant for the practical realization of such FQH states with ultracold atoms in an optical lattice, including the presence of a long-range dipole interaction which can improve the energy gap and stabilize the ground state. We also investigate a detection technique based on Bragg spectroscopy to probe these systems in an experimental realization

  3. FFTF Authorization Agreement

    Energy Technology Data Exchange (ETDEWEB)

    DAUTEL, W.A.


    The purpose of the Authorization Agreement is to serve as a mechanism whereby the U.S. Department of Energy, Richland Operations Office (RL) and Fluor Hanford (FH) jointly clarify and agree to key conditions for conducting work safely and efficiently.

  4. International environmental agreements

    NARCIS (Netherlands)

    de Zeeuw, Aart


    The regulation of environmental externalities at the global level requires international agreements between sovereign states. Game theory provides an appropriate theoretical tool for analysis. However, game theory can result in a wide range of outcomes, and therefore it is important to discuss the

  5. Nonadiabatic effects in the Quantum Hall regime

    International Nuclear Information System (INIS)

    Page, D.A.; Brown, E.


    The authors consider the effect of a finite electric field on the states of a Bloch electron in two dimensions, with a uniform magnetic field present. They make use of the concept of electric time translation symmetry and treat the electric and magnetic fields symmetrically in a time dependent formalism. In addition to a wave vector k, the states are characterized by a frequency specifying the behavior under electric time translations. An effective Hamiltonian is employed to obtain the splitting of an isolated Bloch band into open-quotes frequencyclose quotes subbands. The time-averaged velocity and energy of the states are expressed in terms of the frequency dispersion. The relationship to the Stark ladder eigenstates in a scalar potential representation of the electric field is examined. This is seen to justify the use of the averaged energy in determining occupation of the states. In the weak electric field (adiabatic) limit, an expression is recovered for the quantized Hall conductivity of a magnetic subband as a topological invariant. A numerical procedure is outlined and results obtained over a range of electric field strengths. A transition between strong and weak field regimes is seen, with level repulsions between the frequencies playing an important role. The numerical results show how the magnetic subband structure and quantized Hall conductivity emerge as the electric field becomes weaker. In this regime, the behavior can be understood by comparison to the predictions of the adiabatic approximation. The latter predicts crossings in the frequencies at certain locations in wave vector space. Nonadiabatic effects are seen to produce gaps in the frequency spectrum at these locations. 35 refs., 14 figs

  6. Resident Characteristics Report (United States)

    Department of Housing and Urban Development — The Resident Characteristics Report summarizes general information about households who reside in Public Housing, or who receive Section 8 assistance. The report...

  7. Impact of Smoke-Free Residence Hall Policies: The Views of Administrators at 3 State Universities (United States)

    Gerson, Megan


    Nationwide efforts to protect the public against the health effects of secondhand smoke have prompted college and university administrators to adopt more restrictive smoking policies. Some campus officials are concerned that new policies will lead to student backlash, increased staff workloads, and an increased economic burden. To understand the…

  8. Transport measurements of GaAs/AlGaAs devices in the ``anti-Hall-bar within a Hall bar" geometry (United States)

    Kriisa, Annika; Mani, Ramesh


    Hall effect measurements are often carried out in the Hall geometry, which is a thin rectangular plate with current and Hall voltage contacts at the external boundary. The motivation of this study is to further understand the impact on Hall effect when a hole is inserted inside the Hall geometry. One way on conducting this investigation is to superimpose an ``anti-Hall bar'' inside the standard Hall bar, where the anti Hall bar is actually the hole inside the Hall device with contacts on the inside boundary of this hole. This configuration is thought to generate an ordinary Hall effect within the interior boundary. One believes that it might also be possible to simultaneously realize multiple independent Hall effects by injecting multiple currents into the multiply connected device [1]. We have experimentally studied the Hall effect in the doubly connected ``anti-Hall bar within a Hall bar'' geometry fabricated out of the GaAs/AlGaAs semiconductor system, and convey the results in this presentation. [4pt] [1] R. G. Mani and K. von Klitzing, Z. Phys. B 92, 335 (1993).


    Directory of Open Access Journals (Sweden)

    Bujorel FLOREA


    Full Text Available The study presented herein represents a field with good present and future perspectives, especially because real estate property is not under the incidence of a single normative act regarding the sale-purchase agreement of such goods, and given the fact that there are specific legal provisions with respect to various real estate categories and the localization of such property. The article deals with the sale-purchase agreement of various real estate categories, such as fields, buildings, the correspondent lots, urban area, farm, and forests fields, focusing on some particularities. A special care is attributed to examining the applicable laws with regard to the purchase agreements of field lands, the special conditions to be taken into account, the persons that may act as buyers, including foreigners, those without citizenship, and legal persons of a nationality other than Romanian. Finally, a special concern is given to the formalities required for legally exerting the pre-emptive right and the applicable sanctions in that respect.

  10. Hall conductance and topological invariant for open systems. (United States)

    Shen, H Z; Wang, W; Yi, X X


    The Hall conductivity given by the Kubo formula is a linear response of quantum transverse transport to a weak electric field. It has been intensively studied for quantum systems without decoherence, but it is barely explored for systems subject to decoherence. In this paper, we develop a formulism to deal with this issue for topological insulators. The Hall conductance of a topological insulator coupled to an environment is derived, the derivation is based on a linear response theory developed for open systems in this paper. As an application, the Hall conductance of a two-band topological insulator and a two-dimensional lattice is presented and discussed.

  11. Acoustic investigations of concert halls for rock music

    DEFF Research Database (Denmark)

    Adelman-Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders Christian


    Objective measurement data and subjective evaluations have been collected from 20 small-/medium-sized halls in Denmark used for amplified rhythmic music concerts (pop, rock, jazz). The purpose of the study was to obtain knowledge about optimum acoustic conditions for this type of hall. The study...... is motivated by the fact that most concert tickets sold in Denmark relate to concerts within these genres in this kind of venue. The subjective evaluations were carried out by professional musicians and sound engineers who responded on the basis of their experiences working in these (and other) halls. From...

  12. Effective Field Theory of Fractional Quantized Hall Nematics

    Energy Technology Data Exchange (ETDEWEB)

    Mulligan, Michael; /MIT, LNS; Nayak, Chetan; /Station Q, UCSB; Kachru, Shamit; /Stanford U., Phys. Dept. /SLAC


    We present a Landau-Ginzburg theory for a fractional quantized Hall nematic state and the transition to it from an isotropic fractional quantum Hall state. This justifies Lifshitz-Chern-Simons theory - which is shown to be its dual - on a more microscopic basis and enables us to compute a ground state wave function in the symmetry-broken phase. In such a state of matter, the Hall resistance remains quantized while the longitudinal DC resistivity due to thermally-excited quasiparticles is anisotropic. We interpret recent experiments at Landau level filling factor {nu} = 7/3 in terms of our theory.

  13. Signal conditioning and processing for metallic Hall sensors.

    Czech Academy of Sciences Publication Activity Database

    Entler, Slavomír; Ďuran, Ivan; Sládek, P.; Vayakis, G.; Kočan, M.


    Roč. 123, November (2017), s. 783-786 ISSN 0920-3796. [SOFT 2016: Symposium on Fusion Technology /29./. Prague, 05.09.2016-09.09.2016] R&D Projects: GA MŠk LG14002 Institutional support: RVO:61389021 Keywords : Hall sensor * Lock-in * Synchronous detection * Current spinning * Hall effect * Planar hall effect suppression Subject RIV: JF - Nuclear Energetics OBOR OECD: Nuclear related engineering Impact factor: 1.319, year: 2016

  14. Anomalous Hall effect in Fe/Gd bilayers

    KAUST Repository

    Xu, W. J.


    Non-monotonic dependence of anomalous Hall resistivity on temperature and magnetization, including a sign change, was observed in Fe/Gd bilayers. To understand the intriguing observations, we fabricated the Fe/Gd bilayers and single layers of Fe and Gd simultaneously. The temperature and field dependences of longitudinal resistivity, Hall resistivity and magnetization in these films have also been carefully measured. The analysis of these data reveals that these intriguing features are due to the opposite signs of Hall resistivity/or spin polarization and different Curie temperatures of Fe and Gd single-layer films. Copyright (C) EPLA, 2010

  15. Materials for giant spin Hall effect devices (United States)

    Jayanthinarasimham, Avyaya

    Studies presented in this thesis are an effort to control the growth of beta W and explore the in-plane current induced effects in a beta W and CoFeB bilayer. Physical vapor deposited W films beyond 5 nm transform from beta to the stable bulk alpha phase. beta W films with 5 nm thickness when integrated with the other films for large scale fabrication presents a small process window for etch and deposition errors. Also, CoFeB on W does not generate perpendicular magnetic anisotropy (PMA) even when it is capped with MgOjTa(Capping) layers. The beta W with larger thickness process window and a CoFeB with PMA deposited on top of W is necessary for an ideal functioning spin Hall effect (SHE) device. This thesis will focus on overcoming the above mentioned challenges. 2 sccm of O2 gas was introduced during the growth of beta W, this resulted in thicker films with beta W. If a large amount of O2 was introduced, it resulted in complete oxidation and loss of crystallinity. Thus an optimum amount of oxygen is necessary. However, introducing O2 during the deposition can effect other metals present on the wafer, which is not ideal. N2 was utilized to achieve thicker beta W films. Upon introducing N with similar concentration of O, it lead to amorphization of W, thus revealing a kinetic control. A pulsed N2 of 1 sccm at 2-second period was used to kinetically control the growth of beta W. Both the techniques were able to grow beta W from 5 nm up to 20 nm thick films. Films with N-assisted growth exhibited lower resistance and higher metallic character. 1 nm Ta, Mo and CoFe were used as insert layers between beta W and CoFeB to induce PMA. 1 nm Mo insert layer and 5 nm Mo under layer have largely different interfaces with CoFeB even when annealed in ultra high vacuum (UHV) environment. Thus, 1 nm Mo layer does not show any PMA. The CoFe insert layer adds to the bulk anisotropy and dominates the interface anisotropy, and does not lead to any PMA. The 1 nm Ta insert exhibits

  16. Direct Drive Hall Thruster System Development (United States)

    Hoskins, W. Andrew; Homiak, Daniel; Cassady, R. Joseph; Kerslake, Tom; Peterson, Todd; Ferguson, Dale; Snyder, Dave; Mikellides, Ioannis; Jongeward, Gary; Schneider, Todd


    The sta:us of development of a Direct Drive Ha!! Thruster System is presented. 13 the first part. a s:udy of the impacts to spacecraft systems and mass benefits of a direct-drive architecture is reviewed. The study initially examines four cases of SPT-100 and BPT-4000 Hall thrusters used for north-south station keeping on an EXPRESS-like geosynchronous spacecraft and for primary propulsion for a Deep Space- 1 based science spacecraft. The study is also extended the impact of direct drive on orbit raising for higher power geosynchronous spacecraft and on other deep space missions as a function of power and delta velocity. The major system considerations for accommodating a direct drive Hall thruster are discussed, including array regulation, system grounding, distribution of power to the spacecraft bus, and interactions between current-voltage characteristics for the arrays and thrusters. The mass benefit analysis shows that, for the initial cases, up to 42 kg of dry mass savings is attributable directly to changes in the propulsion hardware. When projected mass impacts of operating the arrays and the electric power system at 300V are included, up to 63 kg is saved for the four initial cases. Adoption of high voltage lithium ion battery technology is projected to further improve these savings. Orbit raising of higher powered geosynchronous spacecraft, is the mission for which direct drive provides the most benefit, allowing higher efficiency electric orbit raising to be accomplished in a limited period of time, as well as nearly eliminating significant power processing heat rejection mass. The total increase in useful payload to orbit ranges up to 278 kg for a 25 kW spacecraft, launched from an Atlas IIA. For deep space missions, direct drive is found to be most applicable to higher power missions with delta velocities up to several km/s , typical of several Discovery-class missions. In the second part, the status of development of direct drive propulsion power

  17. Hall penetration of a magnetic field into a uniform conductor

    International Nuclear Information System (INIS)

    Gordeev, A.V.


    It is shown that magnetic fields can convect into a uniform conductor due to the breakdown of quasineutrality associated with the Hall field. The nonlinear equation describing this process is derived and studied. 9 refs., 2 figs

  18. Quantum Hall Ferroelectrics and Nematics in Multivalley Systems (United States)

    Sodemann, Inti; Zhu, Zheng; Fu, Liang


    We study broken symmetry states at integer Landau-level fillings in multivalley quantum Hall systems whose low-energy dispersions are anisotropic. When the Fermi surface of individual pockets lacks twofold rotational symmetry, like in bismuth (111) [Feldman et al. , Observation of a Nematic Quantum Hall Liquid on the Surface of Bismuth, Science 354, 316 (2016), 10.1126/science.aag1715] and in Sn1 -xPbxSe (001) [Dziawa et al., Topological Crystalline Insulator States in Pb1 -xSnxSe , Nat. Mater. 11, 1023 (2012), 10.1038/nmat3449] surfaces, interactions tend to drive the formation of quantum Hall ferroelectric states. We demonstrate that the dipole moment in these states has an intimate relation to the Fermi surface geometry of the parent metal. In quantum Hall nematic states, like those arising in AlAs quantum wells, we demonstrate the existence of unusually robust Skyrmion quasiparticles.

  19. High Throughput Hall Thruster for Small Spacecraft, Phase II (United States)

    National Aeronautics and Space Administration — Busek is developing a high throughput nominal 100-W Hall Effect Thruster. This device is well sized for spacecraft ranging in size from several tens of kilograms to...

  20. Performance of an 8 kW Hall Thruster

    National Research Council Canada - National Science Library

    Pote, B


    ... in addition to high Isp for station keeping. To satisfy these requirements, Busek Co. embarked on the development of a novel, high power Hall thruster, capable of efficient operation over a broad range of Isp and thrust...

  1. Preliminary Study of Arcjet Neutralization of Hall Thruster Clusters (Postprint)

    National Research Council Canada - National Science Library

    Walker, Quentin E; Cappelli, Mark A; Hargus, William A


    ... to a surrogate anode from the plume of low power arcjets operating on hydrogen and helium, and then demonstrate the first successful operation of a low power Hall thruster-arcjet neutralizer package...

  2. Measuring the Hall weighting function for square and cloverleaf geometries (United States)

    Scherschligt, Julia K.; Koon, Daniel W.


    We have directly measured the Hall weighting function—the sensitivity of a four-wire Hall measurement to the position of macroscopic inhomogeneities in Hall angle—for both a square shaped and a cloverleaf specimen. Comparison with the measured resistivity weighting function for a square geometry [D. W. Koon and W. K. Chan, Rev. Sci. Instrum. 69, 12 (1998)] proves that the two measurements sample the same specimen differently. For Hall measurements on both a square and a cloverleaf, the function is nonnegative with its maximum in the center and its minimum of zero at the edges of the square. Converting a square into a cloverleaf is shown to dramatically focus the measurement process onto a much smaller portion of the specimen. While our results agree qualitatively with theory, details are washed out, owing to the finite size of the magnetic probe used.

  3. What do you measure when you measure the Hall effect? (United States)

    Koon, D. W.; Knickerbocker, C. J.


    A formalism for calculating the sensitivity of Hall measurements to local inhomogeneities of the sample material or the magnetic field is developed. This Hall weighting function g(x,y) is calculated for various placements of current and voltage probes on square and circular laminar samples. Unlike the resistivity weighting function, it is nonnegative throughout the entire sample, provided all probes lie at the edge of the sample. Singularities arise in the Hall weighting function near the current and voltage probes except in the case where these probes are located at the corners of a square. Implications of the results for cross, clover, and bridge samples, and the implications of our results for metal-insulator transition and quantum Hall studies are discussed.

  4. Iodine Hall Thruster for Space Exploration, Phase I (United States)

    National Aeronautics and Space Administration — Busek Co Inc proposes to develop a high power (high thrust) electric propulsion system featuring an iodine fueled Hall Effect Thruster (HET). The system to be...

  5. Magnetohydrodynamic simulations of Gamble I POS with Hall effect

    International Nuclear Information System (INIS)

    Roderick, N.F.; Frese, M.H.; Peterkin, R.E.; Payne, S.S.


    Two dimensional single fluid magnetohydrodynamic simulations have been conducted to investigate the effects of the Hall electric field on magnetic field transport in plasma opening switches of the type used on Gamble I. The Hall terms were included in the magnetic field transport equation in the two dimensional simulation code MACH2 through the use of a generalized Ohm's law. Calculations show the Hall terms augment the field transport previously observed to occur through ion fluid motion and diffusion. For modest values of microturbulent collision frequency, board current channels were observed . Results also show the magnetic field transport to be affected by the cathode boundary conditions with the Hall terms included. In all cases center of mass motion was slight

  6. Magnesium Hall Thruster for Solar System Exploration, Phase II (United States)

    National Aeronautics and Space Administration — The innovation being developed in this program is a Mg Hall Effect Thruster system that would open the door for In-Situ Resource Utilization based solar system...

  7. Hall Mobility of Amorphous Ge2Sb2Te5

    National Research Council Canada - National Science Library

    Baily, S. A; Emin, David; Li, Heng


    The electrical conductivity, Seebeck coefficient, and Hall coefficient of 3 micron thick films of amorphous Ge2Sb2Te5 have been measured as functions of temperature from room temperature down to as low as 200 K...

  8. Quantum Computing With Quasiparticles of the Fractional Quantum Hall Effect

    National Research Council Canada - National Science Library

    Averin, Dmitri


    The focus of this project was the theoretical study of quantum computation based on controlled transfer of individual quasiparticles in systems of quantum antidots in the regime of the Fractional Quantum Hall Effect (FQHE...

  9. Low Temperature Hall Measurements of Neutron Irradiated Silicon Carbide

    National Research Council Canada - National Science Library

    Bonavita, Ange1o


    .... No features suggesting annealing were found below a temperature of 340K. Temperature dependant Hall effect measurements were taken over a range of 100K to 340K recording resistivity, carrier densities, and mobility...

  10. Simultaneous effects of Hall and convective conditions on peristaltic ...

    Indian Academy of Sciences (India)

    stress fluid in an inclined asymmetric channel with convective conditions. Soret and Dufour and Hall effects are taken into account. Analysis has been carried out in a wave frame of reference. Expressions for velocity, pressure gradient, temperature ...

  11. High Input Voltage Hall Thruster Discharge Converter, Phase I (United States)

    National Aeronautics and Space Administration — The overall scope of this Phase I/II effort is the development of a high efficiency 15kW (nominal) Hall thruster discharge converter. In Phase I, Busek Co. Inc. will...

  12. A High Performance Cathode Heater for Hall Thrusters, Phase I (United States)

    National Aeronautics and Space Administration — High current hollow cathodes are the baseline electron source for next generation high power Hall thrusters. Currently for electron sources providing current levels...

  13. Hall effects and related phenomena in disordered Rashba 2DEG

    International Nuclear Information System (INIS)

    Inoue, Jun-ichiro; Kato, Takashi; Bauer, Gerrit E W; Molenkamp, Laurens W


    We review our recent work on the spin and anomalous Hall effects and other related phenomena caused by the intrinsic spin–orbit interaction. We focus our attention on disorder effects on these transport properties by adopting a model of a two-dimensional electron gas with a Rashba-type spin–orbit interaction. A spin-polarized model is adopted to calculate the anomalous Hall effect and anisotropic magnetoresistance. It is shown that the spin Hall conductivity in the ballistic transport regime is cancelled by the so-called vertex corrections for the disorder scattering, and that the anomalous Hall conductivity and anisotropic magnetoresistance vanish unless the lifetime is spin dependent. We further present results on spin accumulation under an electric field

  14. Dual Mode Low Power Hall Thruster, Phase I (United States)

    National Aeronautics and Space Administration — Sample and return missions desire and missions like Saturn Observer require a low power Hall thruster that can operate at high thrust to power as well as high...

  15. Positive operator valued measures and the quantum Monty Hall problem

    Directory of Open Access Journals (Sweden)

    Claudia Zander


    Full Text Available A quantum version of the Monty Hall problem, based upon the Positive Operator Valued Measures (POVM formalism, is proposed. It is shown that basic normalization and symmetry arguments lead univocally to the associated POVM elements, and that the classical probabilities associated with the Monty Hall scenario are recovered for a natural choice of the measurement operators.Uma visão quântica do problema Monty Hall é proposta baseada no formalismo das Medidas Avaliadas do Operador Positivo (POVM. Demonstra-se que os argumentos de normalização básica e simetria levam de maneira inequívoca para elementos associados a POVM e que as probabilidades clássicas associadas ao cenário Monty Hall são recuperadas para uma escolha natural de medidas operadoras.

  16. High Throughput Hall Thruster for Small Spacecraft Project (United States)

    National Aeronautics and Space Administration — Busek Co. Inc. proposes to develop a high throughput, nominal 100 W Hall Effect Thruster (HET). This HET will be sized for small spacecraft (< 180 kg), including...

  17. Imaging of Low Compressibility Strips in the Quantum Hall Liquid


    Finkelstein, G.; Glicofridis, P. I.; Tessmer, S. H.; Ashoori, R. C.; Melloch, M. R.


    Using Subsurface Charge Accumulation scanning microscopy we image strips of low compressibility corresponding to several integer Quantum Hall filling factors. We study in detail the strips at Landau level filling factors $\

  18. Observation of the anomalous Hall effect in GaAs

    International Nuclear Information System (INIS)

    Miah, M Idrish


    Devices for the direct detection of the spin current, based on the anomalous Hall effect (AHE), are fabricated on n-type GaAs bulk semiconductor materials. The AHE is observed in the device when the photoinduced spin-polarized electrons are injected into it, and it is found that the effect depends on the applied electric field. The origin of the field-dependent observed Hall effect is discussed based on the D'yakonov-Perel' (DP) spin relaxation mechanism. The spin-dependent Hall effect is also found to be enhanced with increasing doping concentration. The present experimental results might have potential applications in semiconductor spintronic devices since the effect is closely related to the spin Hall effect

  19. Observation of the anomalous Hall effect in GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Miah, M Idrish [Nanoscale Science and Technology Centre, School of Science, Griffith University, Nathan, Brisbane, QLD 4111 (Australia); Department of Physics, University of Chittagong, Chittagong, Chittagong - 4331 (Bangladesh)


    Devices for the direct detection of the spin current, based on the anomalous Hall effect (AHE), are fabricated on n-type GaAs bulk semiconductor materials. The AHE is observed in the device when the photoinduced spin-polarized electrons are injected into it, and it is found that the effect depends on the applied electric field. The origin of the field-dependent observed Hall effect is discussed based on the D'yakonov-Perel' (DP) spin relaxation mechanism. The spin-dependent Hall effect is also found to be enhanced with increasing doping concentration. The present experimental results might have potential applications in semiconductor spintronic devices since the effect is closely related to the spin Hall effect.

  20. Iodine Hall Thruster for Space Exploration, Phase II (United States)

    National Aeronautics and Space Administration — In the Phase I program, Busek Co. Inc. tested an existing Hall thruster, the BHT-8000, on iodine propellant. The thruster was fed by a high flow iodine feed system,...

  1. 2D Electrostatic Potential Solver for Hall Thruster Simulation

    National Research Council Canada - National Science Library

    Koo, Justin W


    ...) for Hall thruster simulation. It is based on a finite volume discretization of a current conservation equation where the electron current density is described by a Generalized Ohm's law description...

  2. Quantum Theory of Conducting Matter Superconductivity and Quantum Hall Effect

    CERN Document Server

    Fujita, Shigeji; Godoy, Salvador


    Explains major superconducting properties including zero resistance, Meissner effect, sharp phase change, flux quantization, excitation energy gap, and Josephson effects using quantum statistical mechanical calculations. This book covers the 2D superconductivity and the quantum Hall effects

  3. Magnesium Hall Thruster for Solar System Exploration, Phase I (United States)

    National Aeronautics and Space Administration — Busek proposes to prove the feasibility of a Mg Hall effect thruster system that would open the door for In-Situ Resource Utilization (ISRU) based solar system...

  4. International nuclear agreements

    International Nuclear Information System (INIS)

    Miatello, A.; Severino, R.


    This multilingual glossary, in the laborious compilation of which the authors have been greatly assisted by a group of professional translators and experts, presents for the first time a substantial number of entries in four languages (English, French, German and Italian), whose terminology and phraseology, all bearing the appropriate normative reference, has been drawn from the official text of the most relevant international agreements on nuclear policy. It is complemented by a thorough critical study on the status of nonproliferation by Lawrence Scheinman and Josef Pilat. Librarians, translators and interpreters as well as scholars and researchers in international law will find this volume a reference tool of specific interest

  5. Agreement in Persian

    Directory of Open Access Journals (Sweden)

    Lofti, Ahmad R.


    Full Text Available This article investigates agreement as a number marking mechanism in Persian. The mechanism differs from number marking on nominals in that with an inanimate plural subject, the SG verbal ending signals a collective conceptualization of the experience where the members of the group are considered together as a single unit. The PL ending, on the other hand, signals a distributive conceptualization where the entities are individuated; hence, they are considered to be dispersed over space, or distinct in sort or time. Autonomy - whether the entity is conceived of as governing the course of events or not - seems to underlie the choice between SG and PL.

  6. Community-based naming agreement, familiarity, image agreement and visual complexity ratings among adult Indians

    Directory of Open Access Journals (Sweden)

    George Annamma


    Full Text Available The validity of Snodgrass and Vanderwart pictures and their norms derived on a western population on naming, familiarity, imageability and visual-complexity, is not established on a population with cultural background different from the west. We developed, therefore, a set of culturally appropriate pictures for and derived norms on Indians. Line-drawings of 103 concepts (67 from Snodgrass and Vanderwart, 36 new from 10 semantic-categories were normed on 200 community-based older subjects. Only 31% of the Snodgrass and Vanderwart items showed a concept-agreement on the Indians comparable to western norms. Naming, familiarity and image-agreement mutually correlated but not with visual-complexity. Low-education and rural-residence tended to reduced concept-agreement. The output of this study will be of use in national and cross-national studies.

  7. The integer quantum hall effect revisited

    Energy Technology Data Exchange (ETDEWEB)

    Michalakis, Spyridon [Los Alamos National Laboratory; Hastings, Matthew [Q STATION, CALIFORNIA


    For T - L x L a finite subset of Z{sup 2}, let H{sub o} denote a Hamiltonian on T with periodic boundary conditions and finite range, finite strength intetactions and a unique ground state with a nonvanishing spectral gap. For S {element_of} T, let q{sub s} denote the charge at site s and assume that the total charge Q = {Sigma}{sub s {element_of} T} q{sub s} is conserved. Using the local charge operators q{sub s}, we introduce a boundary magnetic flux in the horizontal and vertical direction and allow the ground state to evolve quasiadiabatically around a square of size one magnetic flux, in flux space. At the end of the evolution we obtain a trivial Berry phase, which we compare, via a method reminiscent of Stokes Theorem. to the Berry phase obtained from an evolution around an exponentially small loop near the origin. As a result, we show, without any averaging assumption, that the Hall conductance is quantized in integer multiples of e{sup 2}/h up to exponentially small corrections of order e{sup -L/{zeta}}, where {zeta}, is a correlation length that depends only on the gap and the range and strength of the interactions.

  8. Hall MHD reconnection in cometary magnetotail

    International Nuclear Information System (INIS)

    Jovanovic, Dusan; Shukla, Padma Kant; Morfill, Gregor


    The fine structure of cometary tails (swirls, loops and blobs) is studied in the framework of resistive magnetic reconnection without a guide field in a dusty plasma. For a high-beta plasma (β ∼ 1) consisting of electrons, ions, and immobile dust grains, a two-fluid description is used to study electromagnetic perturbations with the frequency below Ωi, propagating at an arbitrary angle, and including the effects of Hall current. A zero-order current associated with the anti-parallel magnetic configuration may exist even in the limit of zero plasma temperature in a dusty plasma due to a symmetry breaking between electrons and ions by dust grains that yields an E-vector x B-vector current. In the perturbed state, a new linear electromagnetic mode is found in dusty plasma which is evanescent below the Rao cut-off frequency and has the characteristic wavelength comparable to the ion skin depth, which enables the reconnection at short spatial scales. The role of the dust is found to be twofold, yielding a new mode outside of the current sheet and altering the continuity conditions at its edge by an inhomogeneous Doppler shift associated with the E-vector x B-vector current

  9. Brand new hall in the main building

    CERN Multimedia

    Corinne Pralavorio


    The renovation of the UNIQA and post office premises is getting under way, with their reopening scheduled for the spring.   The renovation of the large hall in the main building (Building 500) has finally reached the home straight. As of this week, building contractors will get to work on the last part – the offices of UNIQA and La Poste. In the last week of November, the two concessions moved their offices across Route Scherrer to the same part of Building 510 where UBS was temporarily housed during the bank’s refurbishment. Their services were therefore unavailable for one day. The renovation work will last until the spring, with the new offices expected to open in May 2015. Between now and then, the windows and insulation will be completely refitted, with a view to reducing heat loss considerably, and, above all, the premises will be modernised to improve customer reception and service. For example, UNIQA’s new premises will feature a confidential area, guarantee...

  10. Following the Path Blazed by Jan Hall (United States)

    Hollberg, Leo

    It was a great pleasure to gather with friends in August 2004 for the symposium honoring Jan Hall and celebrating his 70th birthday, and this book provides a unique opportunity to record some words commemorating Jan's incredible contributions to science and to our lives. At best, my recollections are a faded, myopic snapshot of some events that come to mind after many years of association with Jan. Reflecting on the years that have passed since I first entered Jan's lab, I see that many things have changed, technology has advanced (mostly for the better), the world has evolved in dramatic and significant ways (some good and some not), and I have grown older (but unfortunately not wiser as one might have hoped). Nonetheless, after many years, I find myself still following the path pointed out by Jan's visions and investing most of my productive time and energy working as a scientist trying to get atoms, lasers, electronics, (and the institutional bureaucracy that comes along with them) to work in some kind of harmony…

  11. Acoustics in Halls for Speech and Music (United States)

    Gade, Anders C.

    This chapter deals specifically with concepts, tools, and architectural variables of importance when designing auditoria for speech and music. The focus will be on cultivating the useful components of the sound in the room rather than on avoiding noise from outside or from installations, which is dealt with in Chap. 11. The chapter starts by presenting the subjective aspects of the room acoustic experience according to consensus at the time of writing. Then follows a description of their objective counterparts, the objective room acoustic parameters, among which the classical reverberation time measure is only one of many, but still of fundamental value. After explanations on how these parameters can be measured and predicted during the design phase, the remainder of the chapter deals with how the acoustic properties can be controlled by the architectural design of auditoria. This is done by presenting the influence of individual design elements as well as brief descriptions of halls designed for specific purposes, such as drama, opera, and symphonic concerts. Finally, some important aspects of loudspeaker installations in auditoria are briefly touched upon.

  12. What is the Hallé? | Smith | Philosophical Papers

    African Journals Online (AJOL)

    I address what I call 'the number issue', which is raised by our ordinary talk and beliefs about certain social groups and institutions, and I take the Hallé orchestra as my example. The number issue is that of whether the Hallé is one individual or several individuals. I observe that if one holds that it is one individual, one faces ...

  13. Energy Spectrum and Quantum Hall Effect in Twisted Bilayer Graphene


    Moon, Pilkyung; Koshino, Mikito


    We investigate the electronic spectra and quantum Hall effect in twisted bilayer graphenes with various rotation angles under magnetic fields, using a model rigorously including the interlayer interaction. We describe the spectral evolution from discrete Landau levels in the weak field regime to the fractal band structure in the strong field regime, and estimate the quantized Hall conductivity for each single gap. In weak magnetic fields, the low-energy conduction band of the twisted bilayer ...

  14. The Hall Effect in Hydrided Rare Earth Films (United States)

    Koon, D. W.; Azofeifa, D. E.; Clark, N.

    We describe two new techniques for measuring the Hall effect in capped rare earth films during hydriding. In one, we simultaneously measure resistivity and the Hall coefficient for a rare earth film covered with four different thicknesses of Pd, recovering the charge transport quantities for both materials. In the second technique, we replace Pd with Mn as the covering layer. We will present results from both techniques.

  15. Spin and Isospin: Exotic Order in Quantum Hall Ferromagnets (United States)

    Girvin, Steven M.

    Quantum mechanics is a strange business, and the quantum physics of strongly correlated many-electron systems can be stranger still. Good examples are the various quantum Hall effects. They are among the most remarkable many-body quantum phenomena discovered in the second half of the 20th century, comparable in intellectual import to superconductivity and superfluidity. The quantum Hall effects are an extremely rich set of phenomena with deep and truly fundamental theoretical implications...

  16. The Quantum Hall Effect: Novel Excitations and Broken Symmetries


    Girvin, Steven M.


    These pedagogical lecture notes present a general introduction to most aspects of the integer and fractional quantum Hall effects. This is followed by an extensive discussion of quantum Hall ferromagnetism, both for spins in single-layer systems and `pseudospins' in double-layer systems. The effective field theories describing various broken symmetry states and `skyrmion' and `meron' spin textures are derived and discussed in some detail. Pedagogical presentations on Berry phases and lowest L...

  17. High-performance LED luminaire for sports hall (United States)

    Lee, Xuan-Hao; Yang, Jin-Tsung; Chien, Wei-Ting; Chang, Jung-Hsuan; Lo, Yi-Chien; Lin, Che-Chu; Sun, Ching-Cherng


    In this paper, we present a luminaire design with anti-glare and energy-saving effects for sports hall. Compared with traditional lamps using in a badminton court, the average illuminance on the ground of the proposed LED luminaire is enhanced about 300%. Besides, the uniformity is obviously enhanced and improved. The switch-on speed of lighting in sports hall is greatly reduced from 5-10 minutes to 1 second. The simulation analysis and the corresponding experiment results are demonstrated.

  18. Project of industrial hall with a bridge crane


    Ambrožič, Klemen


    In graduation thesis design of steel industrial hall with a bridge crane is performed. The first chapter contains technical report of the structure. Followed by the second chapter, which analyzes bridge crane and crane track. The influences of bridge crane are determined. These influences are considered for design of the crane track, fatigue check and displacements of the crane supporting structure. Fatigue check contains basic detail. The third chapter contains analysis of the hall supportin...

  19. Iodine Plasma Species Measurements in a Hall Effect Thruster Plume (United States)


    from a 200 W Hall Effect Thruster fueled by iodine vapor was analyzed. The plasma source included a laboratory propellant feed system and a laboratory...distribution is unlimited Abstract • The plasma plume from a 200 W Hall Effect Thruster fueled by iodine vapor was analyzed. • The plasma source... pressure with I2 – Plume divergence lower with I2 – Dimers (I2+) measured at beam centroid (a few %) Iodine Xenon 7 Distribution A: Approved for public


    Directory of Open Access Journals (Sweden)

    Mihai Daniel ONIȘOR


    Full Text Available Alongside major changes in Romanian criminal law, the plea bargain agreement gave a new approach on the mechanisms of criminal procedure in national law, thus creating a series of problems and divergent interpretations of the content and limits of this mechanism in solving criminal litigation. What motivated us in our scientific analysis was the novelty of the issues that arose both in the doctrine and interpretation of the legal provisions and in the practice of prosecution offices and national courts, the high impact that the new proceedings can have on criminal policy and the need for clear and efficient provisions that can ensure legal certainty. Our paper is divided in four major parts: the nature and object of the agreement, the conditions of plea bargain, the prosecutorial phase, court validation and appeal procedure, in each of these sections taking into account the legal provisions, analyzing working hypothesis, identifying probable issues and problems and providing our opinion on possible solutions. Our findings prove the fact that the novelty aspect of this procedure determined a number of gaps in the law, aspects that can dramatically influence the result of the criminal case and the guarantees that the parties have in criminal law. Moreover it will underline the unclear provisions that make the new law inapplicable in certain cases and leave a number of situations without any lawful solution.

  1. Anisotropic intrinsic spin Hall effect in quantum wires

    International Nuclear Information System (INIS)

    Cummings, A W; Akis, R; Ferry, D K


    We use numerical simulations to investigate the spin Hall effect in quantum wires in the presence of both Rashba and Dresselhaus spin-orbit coupling. We find that the intrinsic spin Hall effect is highly anisotropic with respect to the orientation of the wire, and that the nature of this anisotropy depends strongly on the electron density and the relative strengths of the Rashba and Dresselhaus spin-orbit couplings. In particular, at low densities, when only one subband of the quantum wire is occupied, the spin Hall effect is strongest for electron momentum along the [1-bar 10] axis, which is the opposite of what is expected for the purely 2D case. In addition, when more than one subband is occupied, the strength and anisotropy of the spin Hall effect can vary greatly over relatively small changes in electron density, which makes it difficult to predict which wire orientation will maximize the strength of the spin Hall effect. These results help to illuminate the role of quantum confinement in spin-orbit-coupled systems, and can serve as a guide for future experimental work on the use of quantum wires for spin-Hall-based spintronic applications. (paper)

  2. Spin Hall effect and spin swapping in diffusive superconductors (United States)

    Espedal, Camilla; Lange, Peter; Sadjina, Severin; Mal'shukov, A. G.; Brataas, Arne


    We consider the spin-orbit-induced spin Hall effect and spin swapping in diffusive superconductors. By employing the nonequilibrium Keldysh Green's function technique in the quasiclassical approximation, we derive coupled transport equations for the spectral spin and particle distributions and for the energy density in the elastic scattering regime. We compute four contributions to the spin Hall conductivity, namely, skew scattering, side jump, anomalous velocity, and the Yafet contribution. The reduced density of states in the superconductor causes a renormalization of the spin Hall angle. We demonstrate that all four of these contributions to the spin Hall conductivity are renormalized in the same way in the superconducting state. In its simplest manifestation, spin swapping transforms a primary spin current into a secondary spin current with swapped current and polarization directions. We find that the spin-swapping coefficient is not explicitly but only implicitly affected by the superconducting gap through the renormalized diffusion coefficients. We discuss experimental consequences for measurements of the (inverse) spin Hall effect and spin swapping in four-terminal geometries. In our geometry, below the superconducting transition temperature, the spin-swapping signal is increased an order of magnitude while changes in the (inverse) spin Hall signal are moderate.

  3. Shear-driven Instabilities in Hall-magnetohydrodynamic Plasmas (United States)

    Bejarano, Cecilia; Gómez, Daniel O.; Brandenburg, Axel


    The large-scale dynamics of plasmas is well described within the framework of magnetohydrodynamics (MHD). However, whenever the ion density of the plasma becomes sufficiently low, the Hall effect is likely to become important. The role of the Hall effect has been studied in several astrophysical plasma processes, such as magnetic reconnection, magnetic dynamo, MHD turbulence, or MHD instabilities. In particular, the development of small-scale instabilities is essential to understand the transport properties in a number of astrophysical plasmas. The magneto-rotational instability (MRI), which takes place in differentially rotating accretion disks embedded in relatively weak magnetic fields, is just one example. The influence of the large-scale velocity flows on small-scale instabilities is often approximated by a linear shear flow. In this paper, we quantitatively study the role of the Hall effect on plasmas embedded in large-scale shear flows. More precisely, we show that an instability develops when the Hall effect is present, which we therefore term as the Hall magneto-shear instability. As a particular case, we recover the so-called MRI and quantitatively assess the role of the Hall effect on its development and evolution.

  4. [Burnout in nursing residents]. (United States)

    Franco, Gianfábio Pimentel; de Barros, Alba Lúcia Bottura Leite; Nogueira-Martins, Luiz Antônio; Zeitoun, Sandra Salloum


    Nursing residents may experience physical and emotional exhaustion from the daily life of attending the Program. The aim of this study was to determine the Burnout incidence among Nursing Residents. An investigative, descriptive, analytical, longitudinal-prospective study was conducted with 16 Residents over two years. The Maslach Burnout Inventory was used, translated and validated for Brazil, as well as a sociodemographic/occupational data tool. Of all residents, 17.2% showed high rates in Emotional Exhaustion and Depersonalization; 18.8% showed impaired commitment in Personal Accomplishment, 75% of which belonged to specialty areas, such as Emergency Nursing, Adult and Pediatric Intensive Care. Age and specialty area were positively correlated with Personal Accomplishment. One of the Residents was identified with changes in three subscales of the Maslach Burnout Inventory, thus characterized as a Burnout Syndrome patient. Nursing Residents have profiles of disease. Knowing these factors can minimize health risks of these workers.

  5. Electrostatic Probe with Shielded Probe Insulator Tube for Low Disturbing Plasma Measurements in Hall Thrusters

    International Nuclear Information System (INIS)

    Staack, D.; Raitses, Y.; Fisch, N.J.


    Electrostatic probes are widely used to measure spatial plasma parameters of the quasi-neutral plasma in Hall thrusters and similar ExB electric discharge devices. Significant perturbations of the plasma, induced by such probes, can mask the actual physics involved in operation of these devices. In Hall thrusters, probe-induced perturbations can produce changes in the discharge current and plasma parameters on the order of their steady state values. These perturbations are explored by varying the material, penetration distance, and residence time of various probe designs. A possible cause of these perturbations appears to be the secondary electron emission, induced by energetic plasma electrons, from insulator ceramic tubes in which the probe wire is inserted. A new probe in which a low secondary electron emission material, such as metal, shields the probe ceramic tube, is shown to function without producing such large perturbations. A segmentation of this shield further prevents probe -induced perturbations, by not shortening the plasma through the conductive shield. In a set of experiments with a segmented shield probe, the thruster was operated in the input power range of 500-2.5 kW and discharge voltages of 200-500 V, while the probe-induced perturbations of the discharge current were below 4% of its steady state value in the region in which 90% of the voltage drop takes place

  6. Zheng Manqing: The Memorial Hall and Legacy of the Master of Five Excellences in Taiwan

    Directory of Open Access Journals (Sweden)

    Russ Mason


    Full Text Available Professor Zheng Manqing (1902-1975, a fine artist and a notable taijiquan disciple of Yang Chengfu, emigrated to Taiwan in 1949 following the Chinese civil war between the Guomindang and Maoist factions. Under Republic of China President Chiang Kai-shek’s Cultural Renaissance Movement, Zheng played an important role in preserving the cultural treasures of traditional China. During the period of Mao Zedong’s Cultural Revolution when the Mainland was veiled to foreign eyes behind the Bamboo Curtain, Zheng was instrumental in introducing taijiquan and other elements of Chinese culture to the West. Zheng passed away at his home in Yonghe, Taiwan in 1975 but not before establishing an international reputation for his mastery in taijiquan and other arts. Recently, a portion of his former residence was converted into a memorial hall (the Zheng Manqing Jinian Guan by senior students interested in preserving his martial tradition, paintings, calligraphy, and other artifacts. This article provides a brief history of Zheng’s life and his legacy in Taiwan, as well as a photographic tour of the Zheng Manqing Memorial Hall.

  7. Observation of the Quantum Hall Effect in Confined Films of the Three-Dimensional Dirac Semimetal Cd3 As2 (United States)

    Schumann, Timo; Galletti, Luca; Kealhofer, David A.; Kim, Honggyu; Goyal, Manik; Stemmer, Susanne


    The magnetotransport properties of epitaxial films of Cd3 As2 , a paradigm three-dimensional Dirac semimetal, are investigated. We show that an energy gap opens in the bulk electronic states of sufficiently thin films and, at low temperatures, carriers residing in surface states dominate the electrical transport. The carriers in these states are sufficiently mobile to give rise to a quantized Hall effect. The sharp quantization demonstrates surface transport that is virtually free of parasitic bulk conduction and paves the way for novel quantum transport studies in this class of topological materials. Our results also demonstrate that heterostructuring approaches can be used to study and engineer quantum states in topological semimetals.

  8. Predicative Adjective Agreement

    DEFF Research Database (Denmark)

    Vikner, Sten


    German is a complicated language. Any speaker of e.g. French or Danish who has ever tried to learn German would agree to this. Coming from languages with only two genders and with no case outside the pronoun system, German, with three genders and with four cases throughout the nominal system, seems...... unjustifiably complicated, as if it had been specially designed to torment poor students. However, there is one area where German agreement morphology could not possibly be simpler, and where German is much easier for non-native speakers than e.g. French or Danish: predicative adjectives. Both gender and number...... distinctions, disappear when adjectives are used predicatively. This paper will try to account for why the Germanic languages that inflect attiributive adjectives but not predicative ones are all SOV-languages (e.g. German, Dutch, Frisian and Yiddish)....

  9. Habitat restoration/enhancement Fort Hall Reservation : 2001 annual report

    International Nuclear Information System (INIS)

    Moser, David C.


    Habitat enhancement, protection and monitoring were the focus of the Resident Fisheries Program during 2001. Enhancement and protection included sloping, fencing and planting willows at sites on Diggie Creek, Clear Creek and Spring Creek. In addition, many previously constructed instream structures (rock barbs and wing dams) were repaired throughout the Fort Hall Indian Reservation (Reservation). In 2001, exclosure fences were erected on Diggie Creek (250 m barbed wire; (70 m jack), Wood Creek (500 m jack), Clear Creek (20 m jack), Ross Fork Creek (200 m jack), West Fork Creek (200 m jack)) and the Portneuf River (1 km barbed wire; 100 m jack). Jack and rail exclosure fences that had deteriorated over the past ten years were repaired at numerous areas throughout the Reservation. Physical sampling during 2001 included sediment and depth surveys (SADMS) in Big Jimmy Creek and Diggie Creek. SADMS, used to track changes in channel morphology and specifically track movements of silt through Bottoms stream systems were completed for eight and nine strata in the Big Jimmy and Diggie Creek, respectively. Baseline SADM data was collected in Diggie Creek to monitor the effects of bank sloping and revegetation on channel morphology and sediment levels through time. Water temperature was monitored (hourly) in Spring Creek, Clear Creek, Ross Fork Creek and Big Jimmy Creek. Biotic sampling included invertebrate sampling in the 200 and 300 series of Clear Creek. Fish population densities and biomass were sampled in Clear Creek 200 and 300 series. Sampling protocols were identical to methods used in past years. Numbers of fish in Clear Creek 300 series remained similar to 2000 while numbers of fish in Clear Creek 200 series dropped to near pre project levels. Salmonid fry densities were monitored near Broncho Bridge and were significantly higher than 2000. A mark-recapture study was initiated in spring 2001 to estimate numbers of spawning adults using the Head End of Spring Creek

  10. Rain Forest Dance Residency. (United States)

    Watson, Dawn


    Outlines the author's experience as a dancer and choreographer artist-in-residence with third graders at a public elementary school, providing a cultural arts experience to tie in with a theme study of the rain forest. Details the residency and the insights she gained working with students, teachers, and theme. (SR)

  11. Psychologic effects of residency. (United States)

    Reuben, D B


    The intense situational and physiologic stresses that accompany postgraduate training may have serious psychosocial ramifications. Although only a small proportion of residents have overt psychiatric illness, virtually all display some psychologic impairment. Contributing factors include life-changes, stresses associated with providing patient care, loss of social support, long working hours, sleep deprivation, and underlying personality traits of residents. The manifestations of this impairment are variable and may be subtle. In response to these problems, residency programs have taken steps to provide psychosocial support. Unfortunately, most programs do not offer formal support groups or seminars to discuss difficulties that accompany residency. Further definition of the psychosocial effects of residency may prompt changes that make the training of physicians a more humane process.

  12. The Chief Resident Role in Emergency Medicine Residency Programs

    Directory of Open Access Journals (Sweden)

    Hafner, John W. Jr., MD, MPH


    Full Text Available Study Objectives: Although other specialties have examined the role of the chief resident (CR, the role and training of the emergency medicine (EM CR has largely been undefined.Methods: A survey was mailed to all EM CRs and their respective program directors (PD in 124 EM residency programs. The survey consisted of questions defining demographics, duties of the typical CR, and opinions regarding the level of support and training received. Multiple choice, Likert scale (1 strong agreement, 5 strong disagreement and short-answer responses were used. We analyzed associations between CR and PD responses using Chi-square, Student’s T and Mann-Whitney U tests.Results: Seventy-six percent of CRs and 65% of PDs responded and were similar except for age (31 vs. 42 years; p<0.001. CR respondents were most often male, in year 3 of training and held the position for 12 months. CRs and PDs agreed that the assigned level of responsibility is appropriate (2.63 vs. 2.73, p=0.15; but CRs underestimate their influence in the residency program (1.94 vs. 2.34, p=0.002 and the emergency department (2.61 vs. 3.03, p=0.002. The majority of CRs (70% and PDs (77% report participating in an extramural training program, and those CRs who participated in training felt more prepared for their job duties (2.26 vs. 2.73; p=0.03.Conclusion: EM CRs feel they have appropriate job responsibility but believe they are less influential in program and department administration than PD respondents. Extramural training programs for incoming CRs are widely used and felt to be helpful. [West J Emerg Med. 2010; 11(2:120-125.

  13. VHA Data Sharing Agreement Repository (United States)

    Department of Veterans Affairs — The VHA Data Sharing Agreement Repository serves as a centralized location to collect and report on agreements that share VHA data with entities outside of VA. It...

  14. Multifunctional semiconductor micro-Hall devices for magnetic, electric, and photo-detection

    Energy Technology Data Exchange (ETDEWEB)

    Gilbertson, A. M.; Cohen, L. F. [Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ (United Kingdom); Sadeghi, Hatef; Lambert, C. J. [Department of Physics, Lancaster University, Lancaster LA1 4YB (United Kingdom); Panchal, V.; Kazakova, O. [National Physical Laboratory, Teddington TW11 0LW (United Kingdom); Solin, S. A. [Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ (United Kingdom); Department of Physics and Institute for Materials Science and Engineering, Washington University in St. Louis, St. Louis, Missouri 63130 (United States)


    We report the real-space voltage response of InSb/AlInSb micro-Hall devices to local photo-excitation, electric, and magnetic fields at room temperature using scanning probe microscopy. We show that the ultrafast generation of localised photocarriers results in conductance perturbations analogous to those produced by local electric fields. Experimental results are in good agreement with tight-binding transport calculations in the diffusive regime. The magnetic, photo, and charge sensitivity of a 2 μm wide probe are evaluated at a 10 μA bias current in the Johnson noise limit (valid at measurement frequencies > 10 kHz) to be, respectively, 500 nT/√Hz; 20 pW/√Hz (λ = 635 nm) comparable to commercial photoconductive detectors; and 0.05 e/√Hz comparable to that of single electron transistors. These results demonstrate the remarkably versatile sensing attributes of simple semiconductor micro-Hall devices that can be applied to a host of imaging and sensing applications.

  15. Seismic contracts and agreements

    International Nuclear Information System (INIS)

    Cooper, N.M.; Krause, V.


    Some points to consider regarding management of seismic projects within the Canadian petroleum industry were reviewed. Seismic projects involve the integration of many services. This paper focused on user-provider relationships, the project planning process, competitive bid considerations, the types of agreement used for seismic and their implications, and the impact that certain points of control may have on a company: (1) initial estimate versus actual cost, (2) liability, (3) safety and operational performance, and (4) quality of deliverables. The objective is to drive home the point that in today's environment where companies are forming, merging, or collapsing on a weekly basis , chain of command and accountability are issues that can no longer be dealt with casually. Companies must form business relationships with service providers with a full knowledge of benefits and liabilities of the style of relationship they choose. Diligent and proactive management tends to optimize cost, safety and liability issues, all of which have a bearing on the points of control available to the company

  16. Seville City Hall Chapter Room ceiling decoration

    Directory of Open Access Journals (Sweden)

    Robador, M. D.


    Full Text Available The present article describes a chemical and physical study of the colour, chemical composition and mineral phases of the decorative materials in the Seville City Hall Chapter House ceiling. The findings showed that the inner most layer of material, calcite, was covered with white lead, in turn concealed under a layer of gilded bole. The ceiling underwent re-gilding, also over bole, due in all likelihood to wear on the original gold leaf. In the nineteenth century, the entire ceiling with the exception of the inscriptions was whitewashed with calcite and white lead. Silver was employed on King John I’s sword (coffer 27. Gold leaf was used to adorn the royal attributes: crowns, belts, sceptres, swords and rosary beads. The high reliefs were likewise gilded. The pigments identified on the ceiling adornments included azurite, malachite, vermilion and gas black. A lime and ground dolomite mortar was used throughout.

    El objetivo de este trabajo es el estudio de diferentes aspectos, como el color, la composición química y las fases mineralógicas presentes en los diferentes materiales que forman la ornamentación del techo de la Sala Capitular del Ayuntamiento de Sevilla, mediante métodos físicos y químicos. Nuestros resultados muestran que el dorado fue realizado sobre una capa de bol previamente depositada sobre una lámina de blanco de plomo que cubría un estrato de calcita. Posteriormente, y probablemente debido a alteraciones en el dorado original, el techo fue de nuevo dorado usando una técnica similar. En el siglo XIX, casi todo el techo, excepto las zonas con inscripciones, fue blanqueado usando una mezcla de calcita y blanco de plomo. Se empleó plata para cubrir la espada del rey Juan I (casetón 27. Finísimas láminas de oro se usaron para decorar los atributos reales: coronas, cinturones, cetros, espadas y rosarios. En diferentes partes de la decoración fueron detectados pigmentos como azurita, malaquita, bermellón y

  17. Concert halls with strong lateral reflections enhance musical dynamics. (United States)

    Pätynen, Jukka; Tervo, Sakari; Robinson, Philip W; Lokki, Tapio


    One of the most thrilling cultural experiences is to hear live symphony-orchestra music build up from a whispering passage to a monumental fortissimo. The impact of such a crescendo has been thought to depend only on the musicians' skill, but here we show that interactions between the concert-hall acoustics and listeners' hearing also play a major role in musical dynamics. These interactions contribute to the shoebox-type concert hall's established success, but little prior research has been devoted to dynamic expression in this three-part transmission chain as a complete system. More forceful orchestral playing disproportionately excites high frequency harmonics more than those near the note's fundamental. This effect results in not only more sound energy, but also a different tone color. The concert hall transmits this sound, and the room geometry defines from which directions acoustic reflections arrive at the listener. Binaural directional hearing emphasizes high frequencies more when sound arrives from the sides of the head rather than from the median plane. Simultaneously, these same frequencies are emphasized by higher orchestral-playing dynamics. When the room geometry provides reflections from these directions, the perceived dynamic range is enhanced. Current room-acoustic evaluation methods assume linear behavior and thus neglect this effect. The hypothesis presented here is that the auditory excitation by reflections is emphasized with an orchestra forte most in concert halls with strong lateral reflections. The enhanced dynamic range provides an explanation for the success of rectangularly shaped concert-hall geometry.

  18. NASA HERMeS Hall Thruster Electrical Configuration Characterization (United States)

    Peterson, Peter Y.; Kamhawi, Hani; Huang, Wensheng; Yim, John; Herman, Daniel; Williams, George; Gilland, James; Hofer, Richard


    The NASA Hall Effect Rocket with Magnetic Shielding (HERMeS) 12.5 kW Technology Demonstration Unit-1 (TDU-1) Hall thruster has been the subject of extensive technology maturation in preparation for development into a flight ready propulsion system. Part of the technology maturation was to test the TDU-1 thruster in several ground based electrical configurations to assess the thruster robustness and suitability to successful in-space operation. The ground based electrical configuration testing has recently been demonstrated as an important step in understanding and assessing how a Hall thruster may operate differently in-space compared to ground based testing, and to determine the best configuration to conduct development and qualification testing. This paper describes the electrical configuration testing of the HERMeS TDU-1 Hall thruster in NASA Glenn Research Center's Vacuum Facility 5. The three electrical configurations examined were 1) thruster body tied to facility ground, 2) thruster floating, and 3) thruster body electrically tied to cathode common. The HERMeS TDU-1 Hall thruster was also configured with two different exit plane boundary conditions, dielectric and conducting, to examine the influence on the electrical configuration characterization.

  19. G. Stanley Hall, Child Study, and the American Public. (United States)

    Young, Jacy L


    In the final decades of the 19th century psychologist Granville Stanley Hall was among the most prominent pedagogical experts in the nation. The author explores Hall's carefully crafted persona as an educational expert, and his engagements with the American public, from 1880 to 1900, arguably the height of his influence. Drawing from accounts of Hall's lecture circuit in the popular press, a map of his talks across the nation is constructed to assess the geographic scope of his influence. These talks to educators on the psychology underlying childhood and pedagogy, and his views and research on child life more generally, were regularly discussed in newspapers and popular periodicals. The venues in which Hall's ideas were disseminated, discussed, and in some cases, dismissed are described. His efforts to mobilize popular support for, and assistance with, his research endeavors in child study are also discussed. Such efforts were controversial both within the burgeoning field of psychology and among the public. Through his various involvements in pedagogy, and concerted efforts to engage with the American public, Hall helped establish psychology's relevance to parenting and educational practices.

  20. Residents in difficulty

    DEFF Research Database (Denmark)

    Christensen, Mette Krogh; O'Neill, Lotte; Hansen, Dorthe Høgh


    Background The majority of studies on prevalence and characteristics of residents in difficulty have been conducted in English-speaking countries and the existing literature may not reflect the prevalence and characteristics of residents in difficulty in other parts of the world such as the Scand......Background The majority of studies on prevalence and characteristics of residents in difficulty have been conducted in English-speaking countries and the existing literature may not reflect the prevalence and characteristics of residents in difficulty in other parts of the world...... such as the Scandinavian countries, where healthcare systems are slightly different. The aim of this study was to examine prevalence and characteristics of residents in difficulty in one out of three postgraduate medical training regions in Denmark, and to produce both a quantifiable overview and in-depth understanding...... of the topic. Methods We performed a mixed methods study. All regional residency program directors (N = 157) were invited to participate in an e-survey about residents in difficulty. Survey data were combined with database data on demographical characteristics of the background population (N = 2399...

  1. Predicting word sense annotation agreement

    DEFF Research Database (Denmark)

    Martinez Alonso, Hector; Johannsen, Anders Trærup; Lopez de Lacalle, Oier


    High agreement is a common objective when annotating data for word senses. However, a number of factors make perfect agreement impossible, e.g. the limitations of the sense inventories, the difficulty of the examples or the interpretation preferences of the annotations. Estimating potential...... agreement is thus a relevant task to supplement the evaluation of sense annotations. In this article we propose two methods to predict agreement on word-annotation instances. We experiment with a continuous representation and a three-way discretization of observed agreement. In spite of the difficulty...

  2. Equilibration of quantum hall edge states and its conductance fluctuations in graphene p-n junctions (United States)

    Kumar, Chandan; Kuiri, Manabendra; Das, Anindya


    We report an observation of conductance fluctuations (CFs) in the bipolar regime of quantum hall (QH) plateaus in graphene (p-n-p/n-p-n) devices. The CFs in the bipolar regime are shown to decrease with increasing bias and temperature. At high temperature (above 7 K) the CFs vanishes completely and the flat quantized plateaus are recovered in the bipolar regime. The values of QH plateaus are in theoretical agreement based on full equilibration of chiral channels at the p-n junction. The amplitude of CFs for different filling factors follows a trend predicted by the random matrix theory. Although, there are mismatch in the values of CFs between the experiment and theory but at higher filling factors the experimental values become closer to the theoretical prediction. The suppression of CFs and its dependence has been understood in terms of time dependent disorders present at the p-n junctions.

  3. Interplay of Chiral and Helical States in a Quantum Spin Hall Insulator Lateral Junction (United States)

    Calvo, M. R.; de Juan, F.; Ilan, R.; Fox, E. J.; Bestwick, A. J.; Mühlbauer, M.; Wang, J.; Ames, C.; Leubner, P.; Brüne, C.; Zhang, S. C.; Buhmann, H.; Molenkamp, L. W.; Goldhaber-Gordon, D.


    We study the electronic transport across an electrostatically gated lateral junction in a HgTe quantum well, a canonical 2D topological insulator, with and without an applied magnetic field. We control the carrier density inside and outside a junction region independently and hence tune the number and nature of 1D edge modes propagating in each of those regions. Outside the bulk gap, the magnetic field drives the system to the quantum Hall regime, and chiral states propagate at the edge. In this regime, we observe fractional plateaus that reflect the equilibration between 1D chiral modes across the junction. As the carrier density approaches zero in the central region and at moderate fields, we observe oscillations in the resistance that we attribute to Fabry-Perot interference in the helical states, enabled by the broken time reversal symmetry. At higher fields, those oscillations disappear, in agreement with the expected absence of helical states when band inversion is lifted.

  4. Mapping degenerate vortex states in a kagome lattice of elongated antidots via scanning Hall probe microscopy (United States)

    Xue, C.; Ge, J.-Y.; He, A.; Zharinov, V. S.; Moshchalkov, V. V.; Zhou, Y. H.; Silhanek, A. V.; Van de Vondel, J.


    We investigate the degeneracy of the superconducting vortex matter ground state by directly visualizing the vortex configurations in a kagome lattice of elongated antidots via scanning Hall probe microscopy. The observed vortex patterns, at specific applied magnetic fields, are in good agreement with the configurations obtained using time-dependent Ginzburg-Landau simulations. Both results indicate that the long-range interaction in this nanostructured superconductor is unable to lift the degeneracy between different vortex states and the pattern formation is mainly ruled by the nearest-neighbor interaction. This simplification makes it possible to identify a set of simple rules characterizing the vortex configurations. We demonstrate that these rules can explain both the observed vortex distributions and the magnetic-field-dependent degree of degeneracy.

  5. Diaphragm Effect of Steel Space Roof Systems in Hall Structures

    Directory of Open Access Journals (Sweden)

    Mehmet FENKLİ


    Full Text Available Hall structures have been used widely for different purposes. They have are reinforced concrete frames and shear wall with steel space roof systems. Earthquake response of hall structures is different from building type structures. One of the most critical nodes is diaphragm effect of steel space roof on earthquake response of hall structures. Diaphragm effect is depending on lateral stiffness capacity of steel space roof system. Lateral stiffness of steel space roof system is related to modulation geometry, support conditions, selected sections and system geometry. In current paper, three representative models which are commonly used in Turkey were taken in to account for investigation. Results of numerical tests were present comparatively

  6. Maximizing utilization of sport halls during peak hours

    DEFF Research Database (Denmark)

    Iversen, Evald Bundgård; Forsberg, Peter

    the number of participants 7.5 persons higher pr. activity compared to club activities. This implies that clubs during peak hours could include more participants. Another possibility to increase utilization is if the management of sport facilities forced sport clubs and other organisers to adapt......BACKGROUNDDuring peak hours (4.30pm-8pm) demand for timeslots in sport halls in Denmark are high and there are few timeslots available. Further, focus on how public resources are spent most efficient is increasing (Iversen, 2013). This makes it interesting to analyse how utilization could...... be increased during peak hours. DATA AND METHODOLOGYData is collected by observation of activities during two weeks on for example whether halls are used or not; the amount of playing field used; and number of participants (Iversen, 2012). Data on 1.331 activities in 36 sport halls across 4 municipalities have...

  7. Admittance of multiterminal quantum Hall conductors at kilohertz frequencies

    International Nuclear Information System (INIS)

    Hernández, C.; Consejo, C.; Chaubet, C.; Degiovanni, P.


    We present an experimental study of the low frequency admittance of quantum Hall conductors in the [100 Hz, 1 MHz] frequency range. We show that the frequency dependence of the admittance of the sample strongly depends on the topology of the contacts connections. Our experimental results are well explained within the Christen and Büttiker approach for finite frequency transport in quantum Hall edge channels taking into account the influence of the coaxial cables capacitance. In the Hall bar geometry, we demonstrate that there exists a configuration in which the cable capacitance does not influence the admittance measurement of the sample. In this case, we measure the electrochemical capacitance of the sample and observe its dependence on the filling factor

  8. Admittance of multiterminal quantum Hall conductors at kilohertz frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Hernández, C. [Departamento de Física, Universidad Militar Nueva Granada, Carrera 11 101-80 Bogotá D.C. (Colombia); Consejo, C.; Chaubet, C., E-mail: [Université Montpellier 2, Laboratoire Charles Coulomb UMR5221, F-34095 Montpellier, France and CNRS, Laboratoire Charles Coulomb UMR5221, F-34095 Montpellier (France); Degiovanni, P. [Université de Lyon, Fédération de Physique Andrée Marie Ampère, CNRS, Laboratoire de Physique de l' Ecole Normale Supérieure de Lyon, 46 allée d' Italie, 69364 Lyon Cedex 07 (France)


    We present an experimental study of the low frequency admittance of quantum Hall conductors in the [100 Hz, 1 MHz] frequency range. We show that the frequency dependence of the admittance of the sample strongly depends on the topology of the contacts connections. Our experimental results are well explained within the Christen and Büttiker approach for finite frequency transport in quantum Hall edge channels taking into account the influence of the coaxial cables capacitance. In the Hall bar geometry, we demonstrate that there exists a configuration in which the cable capacitance does not influence the admittance measurement of the sample. In this case, we measure the electrochemical capacitance of the sample and observe its dependence on the filling factor.

  9. Crossover between spin swapping and Hall effect in disordered systems

    KAUST Repository

    Saidaoui, Hamed Ben Mohamed


    We theoretically study the crossover between spin Hall effect and spin swapping, a recently predicted phenomenon that consists of the interchange between the current flow and its spin polarization directions [M. B. Lifshits and M. I. Dyakonov, Phys. Rev. Lett. 103, 186601 (2009)]. Using a tight-binding model with spin-orbit coupled disorder, spin Hall effect, spin relaxation, and spin swapping are treated on equal footing. We demonstrate that spin swapping and spin Hall effect present very different dependencies as a function of the spin-orbit coupling and disorder strengths and confirm that the former exceeds the latter in the parameter range considered. Three setups are proposed for the experimental observation of the spin swapping effect.

  10. Topological Phase Transitions in the Photonic Spin Hall Effect (United States)

    Kort-Kamp, W. J. M.


    The recent synthesis of two-dimensional staggered materials opens up burgeoning opportunities to study optical spin-orbit interactions in semiconducting Dirac-like systems. We unveil topological phase transitions in the photonic spin Hall effect in the graphene family materials. It is shown that an external static electric field and a high frequency circularly polarized laser allow for active on-demand manipulation of electromagnetic beam shifts. The spin Hall effect of light presents a rich dependence with radiation degrees of freedom, and material properties, and features nontrivial topological properties. We discover that photonic Hall shifts are sensitive to spin and valley properties of the charge carriers, providing an unprecedented pathway to investigate spintronics and valleytronics in staggered 2D semiconductors.

  11. Overview of NASA Iodine Hall Thruster Propulsion System Development (United States)

    Smith, Timothy D.; Kamhawi, Hani; Hickman, Tyler; Haag, Thomas; Dankanich, John; Polzin, Kurt; Byrne, Lawrence; Szabo, James


    NASA is continuing to invest in advancing Hall thruster technologies for implementation in commercial and government missions. The most recent focus has been on increasing the power level for large-scale exploration applications. However, there has also been a similar push to examine applications of electric propulsion for small spacecraft in the range of 300 kg or less. There have been several recent iodine Hall propulsion system development activities performed by the team of the NASA Glenn Research Center, the NASA Marshall Space Flight Center, and Busek Co. Inc. In particular, the work focused on qualification of the Busek 200-W BHT-200-I and development of the 600-W BHT-600-I systems. This paper discusses the current status of iodine Hall propulsion system developments along with supporting technology development efforts.

  12. Life in a university residence: Issues, concerns and responses. (United States)

    Shaikh, Babar T; Deschamps, Jean-Pierre


    Students living in university residences experience frail living conditions, being away from their homes and families, the stress of studies, a bizarre routine, and absence of readily available guidance. Their overall health suffers. Our study aims at collecting information on health and related problems of the students in university residences and to identify the solutions to ameliorate the prevailing situation. A qualitative study conducted in five university residences of Nancy, Metz and Strasbourg, France. The majority of students have complaints about the living conditions in the residences. They mention that they are not in sound health. Stress, depression, fatigue, insomnia, and problems with diet are common. Foreign students suffer more due to culture shock, language, and nostalgia. A tendency for suicides has been observed, especially in girls. Financial problems, too much to study, and relationship break-up are important factors. For their health problems, they generally seek advice from a peer and consume medicines without prescription. Many do not use the "students' health service" because of lack of information or difficult access from certain universities or university residences. To solve their problems and to facilitate their social integration, student volunteers ought to be trained in the university residences because a majority prefers to have their peers' advice. Reinforcement of the role of administration of residences, of student-counselors and of the faculty in the university would be another crucial step. More leisure and social activities are imperative. This study itself constitutes the first element of creating awareness regarding the situation of the health of students living in residence halls in France.

  13. Complex dynamics of the integer quantum Hall effect

    International Nuclear Information System (INIS)

    Trugman, S.A.; Nicopoulos, V.N.; Florida Univ., Gainesville, FL


    We investigate both classical and quantum potential scattering in two dimensions in a magnetic field, with applications to the integer quantum Hall effect. Classical scattering is complex, due in one case to the approach of scattering states to an infinite number of bound states. We show that bound states are generic, and occur for all but extremely smooth scattering potentials (|rvec ∇| → 0). Quantum scattering follows the classical behavior rather closely, exhibiting sharp resonances rather than classical bound states. Extended scatterers provide an explanation for the breakdown of the QHE at a comparatively small Hall voltage. 16 refs., 14 figs

  14. Semiclassical droplet states in matrix quantum Hall effect

    International Nuclear Information System (INIS)

    Cappelli, Andrea; Rodriguez, Ivan D.


    We derive semiclassical ground state solutions that correspond to the quantum Hall states earlier found in the Maxwell-Chern-Simons matrix theory. They realize the Jain composite-fermion construction and their density is piecewise constant as that of phenomenological wave functions. These results support the matrix theory as a possible effective theory of the fractional Hall effect. A crucial role is played by the constraint limiting the degeneracy of matrix states: we find its explicit gauge invariant form and clarify its physical interpretation

  15. Spin-Hall nano-oscillator: A micromagnetic study

    Energy Technology Data Exchange (ETDEWEB)

    Giordano, A.; Azzerboni, B.; Finocchio, G. [Department of Electronic Engineering, Industrial Chemistry and Engineering, University of Messina, C.da di Dio, I-98166 Messina (Italy); Carpentieri, M. [Department of Electrical and Information Engineering, Politecnico of Bari, via E. Orabona 4, I-70125 Bari (Italy); Laudani, A. [Department of Engineering, University of Roma Tre, via V. Volterra 62, I-00146 Roma (Italy); Gubbiotti, G. [Istituto Officina dei Materiali del CNR (CNR-IOM), Unità di Perugia c/o Dipartimento di Fisica e Geologia, Via A. Pascoli, 06123 Perugia (Italy)


    This Letter studies the dynamical behavior of spin-Hall nanoscillators from a micromagnetic point of view. The model parameters have been identified by reproducing recent experimental data quantitatively. Our results indicate that a strongly localized mode is observed for in-plane bias fields such as in the experiments, while predict the excitation of an asymmetric propagating mode for large enough out-of plane bias field similarly to what observed in spin-torque nanocontact oscillators. Our findings show that spin-Hall nanoscillators can find application as spin-wave emitters for magnonic applications where spin waves are used for transmission and processing information on nanoscale.

  16. Theory of the quantized Hall effect. Pt. 3

    International Nuclear Information System (INIS)

    Levine, H.; Pruisken, A.M.M.; Libby, S.B.


    In the previous paper, we have demonstrated the need for a phase transition as a function of theta in the non-liner sigma-model describing the quantized Hall effect. In this work, we present arguments for the occurrence of exactly such a transition. We make use of a dilute gas instanton approximation as well as present a more rigorous duality argument to show that the usual scaling of the conductivity to zero at large distances is altered whenever sigmasub(xy)sup((0)) approx.= 1/2ne 2 /h, n integer. This then completes our theory of the quantized Hall effect. (orig.)

  17. Complex scattering dynamics and the quantum Hall effects

    International Nuclear Information System (INIS)

    Trugman, S.A.


    We review both classical and quantum potential scattering in two dimensions in a magnetic field, with applications to the quantum Hall effect. Classical scattering is complex, due to the approach of scattering states to an infinite number of dynamically bound states. Quantum scattering follows the classical behavior rather closely, exhibiting sharp resonances in place of the classical bound states. Extended scatterers provide a quantitative explanation for the breakdown of the QHE at a comparatively small Hall voltage as seen by Kawaji et al., and possibly for noise effects

  18. Quantum Hall ferromagnetism in II-VI based alloys (United States)

    Jaroszyski, J.; Andrearczyk, T.; Karczewski, G.; Wróbel, J.; Wojtowicz, T.; Papis, E.; Kamiska, E.; Piotrowska, A.; Popovi, Dragana; Dietl, T.


    The article reviews our recent studies on quantum Hall ferromagnetism (QHF) in diluted magnetic semiconductors. We carried out magnetoresistance studies on modulation-doped, gated heterostructures of (Cd,Mn)Te/(Cd,Mg)Te:I.We put into evidence the formation of Ising quantum Hall ferromagnet with Curie temperature TC as high as 2 K. QHF is manifested by anomalous magnetoresistance maxima. Moreover, magnitude of these spikes depends dramatically on the history of the sample, shows hysteresis when either magnetic field or gate voltage are swept, stretched-exponential time evolution characteristic of glassy systems, and strong Barkhausen noise. Our study suggests that these metastabilities stem from the slow dynamics of ferromagnetic domains.

  19. Spin Hall magnetoresistance in antiferromagnet/normal metal bilayers

    KAUST Repository

    Manchon, Aurelien


    We investigate the emergence of spin Hall magnetoresistance in a magnetic bilayer composed of a normal metal adjacent to an antiferromagnet. Based on a recently derived drift diffusion equation, we show that the resistance of the bilayer depends on the relative angle between the direction transverse to the current flow and the Néel order parameter. While this effect presents striking similarities with the spin Hall magnetoresistance recently reported in ferromagnetic bilayers, its physical origin is attributed to the anisotropic spin relaxation of itinerant spins in the antiferromagnet.

  20. Inverse spin Hall effect in Pt/(Ga,Mn)As (United States)

    Nakayama, H.; Chen, L.; Chang, H. W.; Ohno, H.; Matsukura, F.


    We investigate dc voltages under ferromagnetic resonance in a Pt/(Ga,Mn)As bilayer structure. A part of the observed dc voltage is shown to originate from the inverse spin Hall effect. The sign of the inverse spin Hall voltage is the same as that in Py/Pt bilayer structure, even though the stacking order of ferromagnetic and nonmagnetic layers is opposite to each other. The spin mixing conductance at the Pt/(Ga,Mn)As interface is determined to be of the order of 1019 m-2, which is about ten times greater than that of (Ga,Mn)As/p-GaAs.

  1. Magnetoresistance and Hall resistivity of semimetal WTe2 ultrathin flakes. (United States)

    Luo, Xin; Fang, Chi; Wan, Caihua; Cai, Jialin; Liu, Yong; Han, Xiufeng; Lu, Zhihong; Shi, Wenhua; Xiong, Rui; Zeng, Zhongming


    This article reports the characterization of WTe 2 thin flake magnetoresistance and Hall resistivity. We found it does not exhibit magnetoresistance saturation when subject to high fields, in a manner similar to their bulk characteristics. The linearity of Hall resistivity in our devices confirms the compensation of electrons and holes. By relating experimental results to a classic two-band model, the lower magnetoresistance values in our samples is demonstrated to be caused by decreased carrier mobility. The dependence of mobility on temperature indicates the main role of optical phonon scattering at high temperatures. Our results provide more detailed information on carrier behavior and scattering mechanisms in WTe 2 thin films.

  2. Wind tunnel tests of tent halls of different shape

    Directory of Open Access Journals (Sweden)

    Porowska Agnieszka


    Full Text Available Aerodynamic investigations of wind pressure distribution on the surfaces of models of tent halls were carried out in the boundary layer wind tunnel at the Cracow University of Technology. Four types of objects of different shapes and construction were tested. Although tent halls are significantly vulnerable with respect to the wind action, there is no information about pressure distribution on objects of such type in standards, codes and normalization documents. Obtained results indicate that it is necessary to take into account different configurations of wind action while designing of the analysed structures.

  3. Impact of external conditions on energy consumption in industrial halls (United States)

    Żabnieńśka-Góra, Alina


    The energy demand for heating the halls buildings is high. The impact on this may have the technology of production, building construction and technology requirements (HVAC systems). The isolation of the external partitions, the location of the object in relation to the surrounding buildings and the degree of the interior insolation (windows and skylights) are important in the context of energy consumption. The article discusses the impact of external conditions, wind and sunlight on energy demand in the industrial hall. The building model was prepared in IDA ICE 4.0 simulation software. Model validation was done based on measurements taken in the analyzed building.

  4. Enhanced thermoelectric response in the fractional quantum Hall effect (United States)

    Roura-Bas, Pablo; Arrachea, Liliana; Fradkin, Eduardo


    We study the linear thermoelectric response of a quantum dot embedded in a constriction of a quantum Hall bar with fractional filling factors ν =1 /m within Laughlin series. We calculate the figure of merit Z T for the maximum efficiency at a fixed temperature difference. We find a significant enhancement of this quantity in the fractional filling in relation to the integer-filling case, which is a direct consequence of the fractionalization of the electron in the fractional quantum Hall state. We present simple theoretical expressions for the Onsager coefficients at low temperatures, which explicitly show that Z T and the Seebeck coefficient increase with m .

  5. Prediction of liquid metal alloy radiant properties from measurements of the Hall coefficient and the direct current resistivity

    International Nuclear Information System (INIS)

    Havstad, M.A.; Qiu, T.


    The thermal radiative properties of high temperature solid and liquid metal alloys are particularly useful to research and development efforts in laser cladding and machining, electron beam welding and laser isotope separation. However the cost, complexity, and difficulty of measuring these properties have forced the use of crude estimates from the Hagen-Rubens relation, the Drude relations, or extrapolation from low temperature or otherwise flawed data (e.g., oxidized). The authors have found in this work that published values for the Hall coefficient and the electrical resistivity of liquid metal alloys can provide useful estimates of the reflectance and emittance of some groups of binary liquid metal and high temperature solid alloys. The estimation method computes the Drude free electron parameters, and thence the optical constants and the radiant properties from the dependence of the Hall coefficient and direct current resistivity on alloy composition (the Hall coefficient gives the free electron density and the resistivity gives the average time between collisions). They find that predictions of the radiant properties of molten cerium-copper alloy, which use the measured variations in the Hall coefficient and resistivity (both highly nonlinear) as a function of alloy fraction (rather than linear combinations of the values of the pure elements) yield a good comparison to published measurements of the variation of the normal spectral emittance (a different but also nonlinear function) of cerium-copper alloy at the single wavelength available for comparison, 0.645 μm. The success of the approach in the visible range is particularly notable because one expects a Drude based approach to improve with increasing wavelength from the visible into the infrared. Details of the estimation method, the comparison between the calculation and the measured emittance, and a discussion of what groups of elements may also provide agreement is given

  6. Satisfaction among residents in ASHP-accredited pharmacy residency programs. (United States)

    VanDenBerg, C; Murphy, J E


    The level of work satisfaction among pharmacists in ASHP-accredited residencies was studied. In March 1996 a questionnaire designed to measure residency satisfaction was mailed to 697 individuals in ASHP-accredited pharmacy practice and specialty practice residencies. Subjects responded to 16 statements relating to intrinsic and extrinsic determinants of work satisfaction on a scale of 1 to 5, where 1 = strongly disagree and 5 = strongly agree. Questionnaires were returned by 413 (59%) of the residents. The respondents were predominantly women (76%), and most (86%) had at least a Pharm. D. degree. Hospitals were the primary work setting (88%). Of the 413 residents, 305 were in pharmacy practice residencies and 108 were in specialized residencies. None of the mean scores indicated disagreement (scores 3) with the negatively worded statements. The median and mode were equal to 2 (disagree) for the three negatively worded items and 4 (agree) for all but three positively worded items. Only 8% of the residents indicated that they would not accept the residency again if given the chance. Specialized residents tended to rate positively worded statements higher and negatively worded statements lower than pharmacy practice residents. Female residents indicated greater satisfaction than male residents. Pay and benefits were rated slightly better than neutral. Pharmacy residents appeared generally satisfied with their residencies. Specialized pharmacy residents were more satisfied than pharmacy practice residents, and women were more satisfied than men.

  7. Voluntary agreements in environmental policy

    International Nuclear Information System (INIS)

    Torvanger, Asbjoern


    A typically voluntary agreement is signed between the authorities and an industrial sector in order to reduce the emission of environmentally harmful substances. There are many different types of agreements. Voluntary agreements are not strictly voluntary, since in the background there is often some kind of ''threat'' about taxation or fees if the industry is unwilling to cooperate. This type of agreements has become popular in many OECD countries during the last decades. In Norway there are only a few agreements of this type. Experience with the use of voluntary agreements as well as research show that they are less cost-effective than market-based instruments such as taxes and quota systems. If there are great restrictions on the use of taxes and quota systems because of information- or measurement problems, or because these instruments are not politically acceptable, then voluntary agreements may be an interesting alternative. Thus, voluntary agreements are best used as a supplement to other instruments in some niche areas of the environmental policy. In some cases, voluntary agreements may be used between two countries or at a regional level, for example within the EU

  8. Labor Agreement Information System (LAIRS) (United States)

    Office of Personnel Management — The Labor Agreement Information Retrieval System (LAIRS) is a database containing historical information on labor-management relations in the Federal Government. It...

  9. Study of the Accelerating Channel Wall Property Influence on the Hall Thruster Discharge Characteristics

    National Research Council Canada - National Science Library

    Vesselovzorov, Alexandre


    According to the work program and schedule there was developed the methodology of experiments on the discharge chamber material influence on the Hall thruster characteristics there was prepared Hall...

  10. Hall Effect Thruster for High Power Solar Electric Propulsion Technology Demonstration, Phase I (United States)

    National Aeronautics and Space Administration — Busek proposes to develop a flight version of a high power Hall Effect thruster. While numerous high power Hall Effect thrusters have been demonstrated in the...

  11. Measured Early Lateral Energy Fractions in Concert Halls and Opera Houses (United States)

    BARRON, M.


    In the 30 years since early lateral reflections were first suggested as important for concert halls, spatial impression and source broadening have become almost universally accepted as essential characteristics of halls with good acoustics. Two objective measures of source broadening have been proposed. Measured values of the best defined of these measures, the early lateral energy fraction (LF), are considered here. Results from two independent measurement surveys are discussed. Comparisons of LF values by hall show a significant link between hall mean LF and hall width. There is however considerable overlap between measured LF values in different halls so the relevance of describing halls by their mean early lateral energy fraction values is questionable. The behaviour of LF values within auditoria is discussed for different concert hall plan forms and within opera houses. A measure of source broadening including sound level is proposed and results considered in the context of auditorium design.

  12. Burnout Syndrome During Residency. (United States)

    Turgut, Namigar; Karacalar, Serap; Polat, Cengiz; Kıran, Özlem; Gültop, Fethi; Kalyon, Seray Türkmen; Sinoğlu, Betül; Zincirci, Mehmet; Kaya, Ender


    The aim of this study is identified the degree of Burnout Syndrome (BOS) and find out its correlation with years of recidency and sociodemograpfic chareacteristics, training, sleeping habits, such as smoking and alcohol consumption. After approval from the Hospital Ethics Committee and obtaining informed consent, First, second, third, fourth and fifth year of recidency staff (n=127) working in our hospital were involved in this study. The standardized Maslach Burnout Inventory (MBI) was used in this study. Fifty six male (44.1%) and seventy one female (55.9%) residents were enroled in this study (Coranbach Alfa(α)=0.873). 57% of the first year residents smokes cigaret and 54% of them use alcohol. 2% of them gets one day off after hospital night shift, 61% of them suffers from disturbed sleep. 60% of them had been stated that they willingly selected their profession. 61% of them prefers talking to friends and 32% of them prefers shopping to overcome stress. There were statistical difference acording to years of recidency in MBI, Emotional Burnout (EB) and desensitisation scale (DS) points. EB scale points of the second year of residency group was statisticaly higher than fourth year of residency group. DS points of second year of residency group was also statisticaly higher than the third and fourth year of residency group. There was no statistical difference between any groups in Personal Success. BOS is a frequent problem during residency in anaesthesia. Appropriate definition and awareness are the first important steps to prevent this syndrome. Further administrative approaches should be evaluated with regard to their effects.

  13. Experience and grammatical agreement: statistical learning shapes number agreement production. (United States)

    Haskell, Todd R; Thornton, Robert; Macdonald, Maryellen C


    A robust result in research on the production of grammatical agreement is that speakers are more likely to produce an erroneous verb with phrases such as the key to the cabinets, with a singular noun followed by a plural one, than with phrases such as the keys to the cabinet, where a plural noun is followed by a singular. These asymmetries are thought to reflect core language production processes. Previous accounts have attributed error patterns to a syntactic number feature present on plurals but not singulars. An alternative approach is presented in which a process similar to structural priming contributes to the error asymmetry via speakers' past experiences with related agreement constructions. A corpus analysis and two agreement production studies test this account. The results suggest that agreement production is shaped by statistical learning from past language experience. Implications for accounts of agreement are discussed. Copyright 2009 Elsevier B.V. All rights reserved.

  14. Analysis of Resident Case Logs in an Anesthesiology Residency Program

    DEFF Research Database (Denmark)

    Yamamoto, Satoshi; Tanaka, Pedro; Madsen, Matias Vested


    Our goal in this study was to examine Accreditation Council for Graduate Medical Education case logs for Stanford anesthesia residents graduating in 2013 (25 residents) and 2014 (26 residents). The resident with the fewest recorded patients in 2013 had 43% the number of patients compared with the...

  15. Residents as teachers: survey of Canadian family medicine residents. (United States)

    Ng, Victor K; Burke, Clarissa A; Narula, Archna


    To examine Canadian family medicine residents' perspectives surrounding teaching opportunities and mentorship in teaching. A 16-question online survey. Canadian family medicine residency programs. Between May and June 2011, all first- and second-year family medicine residents registered in 1 of the 17 Canadian residency programs as of September 2010 were invited to participate. A total of 568 of 2266 residents responded. Demographic characteristics, teaching opportunities during residency, and resident perceptions about teaching. A total of 77.7% of family medicine residents indicated that they were either interested or highly interested in teaching as part of their future careers, and 78.9% of family medicine residents had had opportunities to teach in various settings. However, only 60.1% of respondents were aware of programs within residency intended to support residents as teachers, and 33.0% of residents had been observed during teaching encounters. It appears that most Canadian family medicine residents have the opportunity to teach during their residency training. Many are interested in integrating teaching as part of their future career goals. Family medicine residencies should strongly consider programs to support and further develop resident teaching skills.

  16. new concepts of a modified hall - petch type relationship

    African Journals Online (AJOL)


    Abstract. A modified form of the Hall - Perch equation, where the average grain diameter is replaced by the surface to volume ratio of internal boundaries (Sv), is considered. Working with this model, a flow stress – Sv relationship dominated by geometrically necessary dislocations (GNDs) is derived for the low strain region.

  17. Suitable reverberation time for halls for rock and pop music

    DEFF Research Database (Denmark)

    Adelman-Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders Christian


    The existing body of literature regarding the acoustic design of concert halls has focused almost exclusively on classical music, although there are many more performances of popular music, including rock and pop. Objective measurements were made of the acoustics of 20 rock music venues in Denmark...

  18. Analysis of Air Breathing Hall-Effect Thruster (Preprint) (United States)


    even more attractive because of multi -years sateJiite missions and high cost of payloads. In a recent paper [I), Diamant has proposed a higher orbital altitude. References ( I) Diamant K. D., "A 2-Stage Cylindrical Hall Thruster for Air Breathing Electrical Propulsion," 46’" AJAA

  19. Tondiraba jäähall = Tondiraba ice arena

    Index Scriptorium Estoniae


    Tondiraba jäähall Tallinnas Varraku tänav 14, valminud 2014. Arhitektid Ott Kadarik, Mihkel Tüür, Kadri Tamme (Kadarik Tüür Arhitektid OÜ), insener Paavo Pikand. Eesti Kultuurkapitali Arhitektuuri sihtkapitali aastapreemia 2014

  20. Mini array of quantum Hall devices based on epitaxial graphene

    Energy Technology Data Exchange (ETDEWEB)

    Novikov, S.; Lebedeva, N. [Department of Micro and Nanosciences, Aalto University, Micronova, Tietotie 3, Espoo (Finland); Hämäläinen, J.; Iisakka, I.; Immonen, P.; Manninen, A. J.; Satrapinski, A. [VTT Technical Research Centre of Finland Ltd., Centre for Metrology MIKES, P.O. Box 1000, 02044 VTT (Finland)


    Series connection of four quantum Hall effect (QHE) devices based on epitaxial graphene films was studied for realization of a quantum resistance standard with an up-scaled value. The tested devices showed quantum Hall plateaux R{sub H,2} at a filling factor v = 2 starting from a relatively low magnetic field (between 4 T and 5 T) when the temperature was 1.5 K. The precision measurements of quantized Hall resistance of four QHE devices connected by triple series connections and external bonding wires were done at B = 7 T and T = 1.5 K using a commercial precision resistance bridge with 50 μA current through the QHE device. The results showed that the deviation of the quantized Hall resistance of the series connection of four graphene-based QHE devices from the expected value of 4×R{sub H,2} = 2 h/e{sup 2} was smaller than the relative standard uncertainty of the measurement (<1 × 10{sup −7}) limited by the used resistance bridge.

  1. Active Learning with Monty Hall in a Game Theory Class (United States)

    Brokaw, Alan J.; Merz, Thomas E.


    The authors describe a game that students can play on the first day of a game theory class. The game introduces the 4 essential elements of any game and is designed so that its sequel, also played on the first day of class, has students playing the well-known Monty Hall game, which raises the question: Should you switch doors? By implementing a…

  2. The Hall-induced stability of gravitating fluids (United States)

    Karmakar, P. K.; Goutam, H. P.


    We analyze the stability behavior of low-density partially ionized self-gravitating magnetized unbounded dusty plasma fluid in the presence of the Hall diffusion effects (HDEs) in the non-ideal magnetohydrodynamic (MHD) equilibrium framework. The effects of inhomogeneous self-gravity are methodically included in the basic model tapestry. Application of the Fourier plane-wave perturbative treatment decouples the structuration representative parameters into a linear generalized dispersion relation (sextic) in a judicious mean-fluid approximation. The dispersion analysis shows that the normal mode, termed as the gravito-magneto-acoustic (GMA) mode, is drastically modified due to the HDEs. This mode is highly dispersive, and driven unstable by the Hall current resulting from the symmetry-breaking of electrons and ions relative to the magnetic field. The mode feature, which is derived from a modified induction with the positive Hall, is against the ideal MHD. It is further demonstrated that the HDEs play stabilizing roles by supporting the cloud against gravitational collapse. Provided that the HDEs are concurrently switched off, the collapse occurs on the global spatial scale due to enhanced inward accretion of the gravitating dust constituents. It is seen explicitly that the enhanced dust-charge leads to stabilizing effects. Besides, the Hall-induced fluctuations, as propagatory wave modes, exhibit both normal and anomalous dispersions. The reliability checkup of the entailed results as diverse corollaries and special cases are illustratively discussed in the panoptic light of the earlier paradigmatic predictions available in the literature.

  3. Audience noise in concert halls during musical performances

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho; Marie, Pierre; Brunskog, Jonas


    Noise generated by the audience during musical performances is audible and sometimes disturbing. In this study, an attempt to estimate such audience noise was carried out. From the recordings of performances in five performance spaces (four concert halls and one opera house), probability density ....... (C) 2012 Acoustical Society of America. []...

  4. Clipboard: Human Y-chromosome: a hall of mirrors

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Biosciences; Volume 28; Issue 5. Clipboard: Human Y-chromosome: a hall of mirrors. B J Rao Kundan Sengupta. Volume 28 Issue 5 September 2003 pp 533-534. Fulltext. Click here to view fulltext PDF. Permanent link: Author Affiliations.

  5. A conformal field theory description of fractional quantum Hall states

    NARCIS (Netherlands)

    Ardonne, E.


    In this thesis, we give a description of fractional quantum Hall states in terms of conformal field theory (CFT). As was known for a long time, the Laughlin states could be written in terms of correlators of chiral vertex operators of a c=1 CFT. It was shown by G. Moore and N. Read that more general

  6. Effect of Hall Current and Finite Larmor Radius Corrections on ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Astrophysics and Astronomy; Volume 37; Issue 3. Effect of Hall Current and Finite Larmor Radius Corrections on Thermal Instability of Radiative Plasma for Star Formation in Interstellar Medium (ISM). Sachin Kaothekar. Research Article Volume 37 Issue 3 September 2016 Article ID 23 ...

  7. Effect of Hall Current and Finite Larmor Radius Corrections on ...

    Indian Academy of Sciences (India)

    discussed the magnetothermal instability with generalized Ohms law taking the effects of electrical resistivity, Hall current, electron inertia, thermal conductivity and radiative heat-loss function. Burkert and Lin (2000) pointed out the importance of thermal instability in the formation of clumpy gas clouds and they showed that.

  8. Audience noise in concert halls during musical performances

    DEFF Research Database (Denmark)

    Marie, Pierre; Jeong, Cheol-Ho; Brunskog, Jonas


    Noise generated by the audience during musical performances is audible and sometimes disturbing. In this study, an attempt to estimate such audience noise was carried out. From the recordings of performances in five performance spaces (four concert halls and one opera house), probability density...

  9. AFM diagnostics of graphene-based quantum Hall devices

    Czech Academy of Sciences Publication Activity Database

    Sikora, A.; Woszczyna, M.; Friedemann, M.; Ahlers, F. J.; Kalbáč, Martin


    Roč. 43, 2-3 (2012), s. 479-486 ISSN 0968-4328 Institutional research plan: CEZ:AV0Z40400503 Keywords : graphene * quantum Hall effect devices * atomic force microscopy Subject RIV: CG - Electrochemistry Impact factor: 1.876, year: 2012

  10. Darrell Hall Covos-Day Books, Weltevreden Park, South Africa ...

    African Journals Online (AJOL)

    personally of the 14th and 66th Batteries and the six naval guns; Long's place was with Buller, from where he could have exercised overall control of the artillery. That way he could have dealt effectively with the ammunition problem. According to Hall, Buller apparently did not know the difference between withdrawing the ...

  11. Effect of Hall Current and Finite Larmor Radius Corrections on ...

    Indian Academy of Sciences (India)

    The finite electrical resistivity removes the effect of magnetic field and the viscosity of the medium removes the effect of FLR from the condition of radiative instability. The Hall parameter affects only the longitudinal mode of propagation and it has no effect on the transverse mode of propagation. Numerical calculation shows ...

  12. Dynamics of antiferromagnetic skyrmion driven by the spin Hall effect (United States)

    Jin, Chendong; Song, Chengkun; Wang, Jianbo; Liu, Qingfang


    Magnetic skyrmion moved by the spin-Hall effect is promising for the application of the generation racetrack memories. However, the Magnus force causes a deflected motion of skyrmion, which limits its application. Here, we create an antiferromagnetic skyrmion by injecting a spin-polarized pulse in the nanostripe and investigate the spin Hall effect-induced motion of antiferromagnetic skyrmion by micromagnetic simulations. In contrast to ferromagnetic skyrmion, we find that the antiferromagnetic skyrmion has three evident advantages: (i) the minimum driving current density of antiferromagnetic skyrmion is about two orders smaller than the ferromagnetic skyrmion; (ii) the velocity of the antiferromagnetic skyrmion is about 57 times larger than the ferromagnetic skyrmion driven by the same value of current density; (iii) antiferromagnetic skyrmion can be driven by the spin Hall effect without the influence of Magnus force. In addition, antiferromagnetic skyrmion can move around the pinning sites due to its property of topological protection. Our results present the understanding of antiferromagnetic skyrmion motion driven by the spin Hall effect and may also contribute to the development of antiferromagnetic skyrmion-based racetrack memories.

  13. Composite fermions a unified view of the quantum Hall regime

    CERN Document Server


    One of the most exciting recent developments to have emerged from the quantum Hall effect is the subject of composite fermions. This important volume gives a self-contained, comprehensive description of the subject, including fundamentals, more advanced theoretical work, and results from experimental observations of composite fermions.

  14. Mechanism of plateau formation in the fractional quantum Hall effect

    International Nuclear Information System (INIS)

    Bruus, H.; Hansen, O.P.; Hansen, E.B.


    Laughlin's fractionally charged quasi-holes and quasi-electrons are assumed to be pinned, and to be subject to a force j vectorxΦ 0 vector from the transport current. A force balance argument then explains the existence of Hall plateaus. (orig.)

  15. Planar Hall effect sensor with magnetostatic compensation layer

    DEFF Research Database (Denmark)

    Dalslet, Bjarke Thomas; Donolato, Marco; Hansen, Mikkel Fougt


    Demagnetization effects in cross-shaped planar Hall effect sensors cause inhomogeneous film magnetization and a hysteretic sensor response. Furthermore, when using sensors for detection of magnetic beads, the magnetostatic field from the sensor edges attracts and holds magnetic beads near the sen...

  16. Planar Hall effect sensor for magnetic micro- and nanobead detection

    DEFF Research Database (Denmark)

    Ejsing, Louise Wellendorph; Hansen, Mikkel Fougt; Menon, Aric Kumaran


    Magnetic bead sensors based on the planar Hall effect in thin films of exchange-biased permalloy have been fabricated and characterized. Typical sensitivities are 3 muV/Oe mA. The sensor response to an applied magnetic field has been measured without and with coatings of commercially available 2 ...

  17. Low-frequency noise in planar Hall effect bridge sensors

    DEFF Research Database (Denmark)

    Persson, Anders; Bejhedb, R.S.; Bejhed, R.S.


    The low-frequency characteristics of planar Hall effect bridge sensors are investigated as function of the sensor bias current and the applied magnetic field. The noise spectra reveal a Johnson-like spectrum at high frequencies, and a 1/f-like excess noise spectrum at lower frequencies, with a kn...

  18. Pragmatic data fusion uncertainty concerns: Tribute to Dave L. Hall

    CSIR Research Space (South Africa)

    Blasch, E


    Full Text Available on Information Fusion (FUSION), 5-8 July 2016, Heidelberg, Germany Pragmatic data fusion uncertainty concerns: Tribute to Dave L. Hall Erik Blasch ; Paulo C. G. Costa ; J. Pieter De Villiers ; Kathryn B. Laskey ; James Llinas ; Anne-Laure Jousselme...

  19. Effect of Hall Current and Finite Larmor Radius Corrections on ...

    Indian Academy of Sciences (India)

    Abstract. The effects of finite ion Larmor radius (FLR) corrections,. Hall current and radiative heat-loss function on the thermal instability of an infinite homogeneous, viscous plasma incorporating the effects of finite electrical resistivity, thermal conductivity and permeability for star formation in interstellar medium have been ...

  20. Hall kirjandus võrgustunud maailmas / Anneli Kuiv

    Index Scriptorium Estoniae

    Kuiv, Anneli


    1997. aasta määratluse kohaselt on hall kirjandus "kirjandus, mida toodetakse kõikidel tasanditel valitsus- ja teadusasutuste, äri- ja tootmisringkondade poolt nii trükituna kui ka elektroonselt, kuid mis ei ole kirjastustööstuse kontrolli all"

  1. Single particle detection: Phase control in submicron Hall sensors

    International Nuclear Information System (INIS)

    Di Michele, Lorenzo; Shelly, Connor; Gallop, John; Kazakova, Olga


    We present a phase-sensitive ac-dc Hall magnetometry method which allows a clear and reliable separation of real and parasitic magnetic signals of a very small magnitude. High-sensitivity semiconductor-based Hall crosses are generally accepted as a preferential solution for non-invasive detection of superparamagnetic nanobeads used in molecular biology, nanomedicine, and nanochemistry. However, detection of such small beads is often hindered by inductive pick-up and other spurious signals. The present work demonstrates an unambiguous experimental route for detection of small magnetic moments and provides a simple theoretical background for it. The reliability of the method has been tested for a variety of InSb Hall sensors in the range 600 nm-5 μm. Complete characterization of empty devices, involving Hall coefficients and noise measurements, has been performed and detection of a single FePt bead with diameter of 140 nm and magnetic moment of μ≅10 8 μ B has been achieved with a 600 nm-wide sensor.

  2. Quantum energy teleportation in a quantum Hall system

    Energy Technology Data Exchange (ETDEWEB)

    Yusa, Go; Izumida, Wataru; Hotta, Masahiro [Department of Physics, Tohoku University, Sendai 980-8578 (Japan)


    We propose an experimental method for a quantum protocol termed quantum energy teleportation (QET), which allows energy transportation to a remote location without physical carriers. Using a quantum Hall system as a realistic model, we discuss the physical significance of QET and estimate the order of energy gain using reasonable experimental parameters.

  3. 78 FR 26682 - Culturally Significant Objects Imported for Exhibition Determinations: “Hall of Ancient Egypt” (United States)


    ... Determinations: ``Hall of Ancient Egypt'' AGENCY: Department of State. ACTION: Notice, correction. SUMMARY: On... determinations made by the Department of State pertaining to the exhibition ``Hall of Ancient Egypt.'' The... additional objects to be included in the exhibition ``Hall of Ancient Egypt,'' imported from abroad for...

  4. Current Percolation in Medium with Boundaries under Quantum Hall Effect Conditions

    Directory of Open Access Journals (Sweden)

    M. U. Malakeeva


    Full Text Available The current percolation has been considered in the medium with boundaries under quantum Hall effect conditions. It has been shown that in that case the effective Hall conductivity has a nonzero value due to percolation of the Hall current through the finite number of singular points (in our model these are corners at the phase joints.

  5. The influence of profiled ceilings on sports hall acoustics : Ground effect predictions and scale model measurements

    NARCIS (Netherlands)

    Wattez, Y.C.M.; Tenpierik, M.J.; Nijs, L.


    Over the last few years, reverberation times and sound pressure levels have been measured in many sports halls. Most of these halls, for instance those made from stony materials, perform as predicted. However, sports halls constructed with profiled perforated steel roof panels have an unexpected

  6. The use of Hall technique preformed metal crowns by specialist paediatric dentists in the UK


    Roberts, A; McKay, A; Albadri, S


    Examines treatment planning involving Hall technique preformed metal crowns by specialists in paediatric dentistry. Explores clinical situations in which specialists in paediatric dentistry feel it is appropriate or not to fit Hall technique preformed metal crowns. Investigates which types of carious lesions are being treated with Hall technique preformed metal crowns by specialists in paediatric dentistry.

  7. Impact of educational intervention on the inter-rater agreement of nasal endoscopy interpretation (United States)

    Colley, Patrick; Mace, Jess C.; Schaberg, Madeleine R.; Smith, Timothy L.; Tabaee, Abtin


    OBJECTIVE Nasal endoscopy is integral to the evaluation of sinonasal disorders. However, prior studies have shown significant variability in the inter-rater agreement of nasal endoscopy interpretation amongst practicing rhinologists. The objective of the current study is to evaluate the inter-rater agreement of nasal endoscopy amongst otolaryngology residents from a single training program at baseline and following an educational intervention. METHODS 11 otolaryngology residents completed nasal endoscopy grading forms for 8 digitally recorded nasal endoscopic examinations. An instructional lecture reviewing nasal endoscopy interpretation was subsequently provided. The residents then completed grading forms for 8 different nasal endoscopic examinations. Inter-rate agreement amongst residents for the pre- and post-lecture videos was calculated using the unweighted Fleiss’ kappa statistic (Kf) and intra-class correlation agreement (ICC). RESULTS Inter-rater agreement improved from a baseline level of fair (Kf range 0.268–0.383) to a post-educational level of moderate (Kf range 0.401–0.547) for nasal endoscopy findings of middle meatus mucosa, middle turbinate mucosa, middle meatus discharge, sphenoethmoid recess mucosa, sphenoethmoid recess discharge and atypical lesions (ICC, pendoscopy interpretation amongst otolaryngology residents. The inter-rater agreement for the majority of the characteristics that were evaluated improved after educational intervention. Further study is needed to improve nasal endoscopy interpretation. PMID:25781864

  8. Scanning Hall Probe Microscopy of Magnetic Vortices inVery Underdoped yttrium-barium-copper-oxide

    Energy Technology Data Exchange (ETDEWEB)

    Guikema, Janice Wynn; /SLAC, SSRL


    Since their discovery by Bednorz and Mueller (1986), high-temperature cuprate superconductors have been the subject of intense experimental research and theoretical work. Despite this large-scale effort, agreement on the mechanism of high-T{sub c} has not been reached. Many theories make their strongest predictions for underdoped superconductors with very low superfluid density n{sub s}/m*. For this dissertation I implemented a scanning Hall probe microscope and used it to study magnetic vortices in newly available single crystals of very underdoped YBa{sub 2}Cu{sub 3}O{sub 6+x} (Liang et al. 1998, 2002). These studies have disproved a promising theory of spin-charge separation, measured the apparent vortex size (an upper bound on the penetration depth {lambda}{sub ab}), and revealed an intriguing phenomenon of ''split'' vortices. Scanning Hall probe microscopy is a non-invasive and direct method for magnetic field imaging. It is one of the few techniques capable of submicron spatial resolution coupled with sub-{Phi}{sub 0} (flux quantum) sensitivity, and it operates over a wide temperature range. Chapter 2 introduces the variable temperature scanning microscope and discusses the scanning Hall probe set-up and scanner characterizations. Chapter 3 details my fabrication of submicron GaAs/AlGaAs Hall probes and discusses noise studies for a range of probe sizes, which suggest that sub-100 nm probes could be made without compromising flux sensitivity. The subsequent chapters detail scanning Hall probe (and SQUID) microscopy studies of very underdoped YBa{sub 2}Cu{sub 3}O{sub 6+x} crystals with T{sub c} {le} 15 K. Chapter 4 describes two experimental tests for visons, essential excitations of a spin-charge separation theory proposed by Senthil and Fisher (2000, 2001b). We searched for predicted hc/e vortices (Wynn et al. 2001) and a vortex memory effect (Bonn et al. 2001) with null results, placing upper bounds on the vison energy inconsistent with

  9. Resident fatigue in otolaryngology residents: a Web based survey. (United States)

    Nida, Andrew M; Googe, Benjamin J; Lewis, Andrea F; May, Warren L


    Resident fatigue has become a point of emphasis in medical education and its effects on otolaryngology residents and their patients require further study. The purpose of our study was to evaluate the prevalence and nature of fatigue in otolaryngology residents, evaluate various quality of life measures, and investigate associations of increased fatigue with resident safety. Anonymous survey. Internet based. United States allopathic otolaryngology residents. None. The survey topics included demographics, residency structure, sleep habits and perceived stress. Responses were correlated with a concurrent Epworth Sleep Scale questionnaire to evaluate effects of fatigue on resident training and quality of life. 190 residents responded to the survey with 178 completing the Epworth Sleep Scale questionnaire. Results revealed a mean Epworth Sleep Scale score of 9.9±5.1 with a median of 10.0 indicating a significant number of otolaryngology residents are excessively sleepy. Statistically significant correlations between Epworth Sleep Scale and sex, region, hours of sleep, and work hours were found. Residents taking in-house call had significantly fewer hours of sleep compared to home call (p=0.01). Residents on "head and neck" (typically consisting of a large proportion of head and neck oncologic surgery) rotations tended to have higher Epworth Sleep Scale and had significantly fewer hours of sleep (p=.003) and greater work hours (potolaryngology residents are excessively sleepy. Our data suggest that the effects of fatigue play a role in resident well-being and resident safety. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Federal Facility Agreement progress report

    Energy Technology Data Exchange (ETDEWEB)


    The (SRS) Federal Facility Agreement (FFA) was made effective by the US. Environmental Protection Agency Region IV (EPA) on August 16, 1993. To meet the reporting requirements in Section XXV of the Agreement, the FFA Progress Report was developed. The FFA Progress Report is the first of a series of quarterly progress reports to be prepared by the SRS. As such this report describes the information and action taken to September 30, 1993 on the SRS units identified for investigation and remediation in the Agreement. This includes; rubble pits, runoff basins, retention basin, seepage basin, burning pits, H-Area Tank 16, and spill areas.

  11. Federal Facility Agreement progress report

    International Nuclear Information System (INIS)


    The (SRS) Federal Facility Agreement (FFA) was made effective by the US. Environmental Protection Agency Region IV (EPA) on August 16, 1993. To meet the reporting requirements in Section XXV of the Agreement, the FFA Progress Report was developed. The FFA Progress Report is the first of a series of quarterly progress reports to be prepared by the SRS. As such this report describes the information and action taken to September 30, 1993 on the SRS units identified for investigation and remediation in the Agreement. This includes; rubble pits, runoff basins, retention basin, seepage basin, burning pits, H-Area Tank 16, and spill areas

  12. Positions of the magnetoroton minima in the fractional quantum Hall effect (United States)

    Balram, Ajit C.; Pu, Songyang


    The multitude of excitations of the fractional quantum Hall state are very accurately understood, microscopically, as excitations of composite fermions across their Landau-like Λ levels. In particular, the dispersion of the composite fermion exciton, which is the lowest energy spin conserving neutral excitation, displays filling-factor-specific minima called "magnetoroton" minima. Simon and Halperin employed the Chern-Simons field theory of composite fermions [Phys. Rev. B 48, 17368 (1993)] to predict the magnetoroton minima positions. Recently, Golkar et al. [Phys. Rev. Lett. 117, 216403 (2016)] have modeled the neutral excitations as deformations of the composite fermion Fermi sea, which results in a prediction for the positions of the magnetoroton minima. Using methods of the microscopic composite fermion theory we calculate the positions of the roton minima for filling factors up to 5/11 along the sequence s/ (2 s + 1) and find them to be in reasonably good agreement with both the Chern-Simons field theory of composite fermions and Golkar et al.'s theory. We also find that the positions of the roton minima are insensitive to the microscopic interaction in agreement with Golkar et al.'s theory. As a byproduct of our calculations, we obtain the charge and neutral gaps for the fully spin polarized states along the sequence s/ (2 s ± 1) in the lowest Landau level and the n = 1 Landau level of graphene.

  13. Spin chirality induced skew scattering and anomalous Hall effect in chiral magnets. (United States)

    Ishizuka, Hiroaki; Nagaosa, Naoto


    Noncoplanar magnetic orders in magnetic metals give rise to an anomalous Hall effect of unconventional origin, which, by the spin Berry phase effect, is known as the topological Hall effect. This effect is pronounced in the low-temperature limit, where the fluctuation of spins is suppressed. In contrast, we here discuss that the fluctuating but locally correlated spins close to the phase boundary give rise to another anomalous Hall effect, that with the opposite sign to the topological Hall effect. Using the Born approximation, we show that the anomalous Hall effect is attributed to the skew scattering induced by the local correlation of spins. The relation of the scalar spin chirality to the skew scattering amplitude is given, and the explicit formula for the Hall conductivity is derived using a semiclassical Boltzmann transport theory. Our theory potentially accounts for the sign change of the anomalous Hall effect observed in chiral magnets in the vicinity of the phase boundary.

  14. Acoustics of the Great Hall of the Moscow State Conservatory after reconstruction in 2010-2011 (United States)

    Kanev, N. G.; Livshits, A. Ya.; Möller, H.


    The Great Hall of the Moscow State Conservatory was built in the early 20th century. For more than 100 years of service, it had a high acoustic reputation both among musicians and audience. By the beginning of the 21st century, the hall was in nearly critical condition. Thus, major renovation was needed. In terms of architectural acoustics, the main task was to keep the good acoustics of the hall. This paper presents the results of acoustic parameter measurements of the hall after Reconstruction in 2010-2011. The parameters of the hall measured before and after reconstruction are also compared. The comparative acoustic characteristics between the Great Hall and world leading concert halls are given.

  15. Material Transfer Agreement (MTA) | FNLCR (United States)

    Material Transfer Agreements are appropriate for exchange of materials into or out of the Frederick National Laboratory for research or testing purposes, with no collaborative research by parties involving the materials.

  16. Corporate Integrity Agreement (CIA) documents (United States)

    U.S. Department of Health & Human Services — OIG negotiates corporate integrity agreements (CIA) with health care providers and other entities as part of the settlement of Federal health care program...

  17. Beta-Testing Agreement | FNLCR (United States)

    Beta-Testing Agreements are appropriate forlimited term evaluation and applications development of new software, technology, or equipment platforms by the Frederick National Laboratory in collaboration with an external commercial partner. It ma

  18. Pesticide Worker Safety Cooperative Agreements (United States)

    The worker safety program cooperative agreements fund projects to educate pesticide applicators, handlers, and farmworkers on working safely with, and around, pesticides. Read about pesticide related grant opportunities and reports from previous grants.

  19. The design and performance of the electromagnetic calorimeters in Hall C at Jefferson Lab

    International Nuclear Information System (INIS)

    Tadevosyan, V; Mkrtchyan, H; Asaturyan, A; Mkrtchyan, A; Zhamkochyan, S


    The design and performance of the electromagnetic calorimeters in the magnetic spectrometers in Hall C at Jefferson Lab are presented. For the existing HMS and SOS spectrometers, construction information and comparisons of simulated and experimental results are presented. The design and simulated performance for a new calorimeter to be used in the new SHMS spectrometer is also presented. We have developed and constructed electromagnetic calorimeters from TF-1 type lead-glass blocks for the HMS and SOS magnetic spectrometers at JLab Hall C. The HMS/SOS calorimeters are of identical design and construction except for their total size. Blocks of dimension 10 cm × 10 cm × 70 cm are arranged in four planes and stacked 13 and 11 blocks high in the HMS and SOS respectively. The energy resolution of these calorimeters is better than 6%/√E, and pion/electron (π/e) separation of about 100:1 has been achieved in energy range 1–5 GeV. Good agreement has been observed between the experimental and GEANT4 simulated energy resolutions. The HMS/SOS calorimeters have been used nearly in all Hall C experiments, providing good energy resolution and a high pion suppression factor. No significant deterioration in their performance has been observed in the course of use since 1994. For the SHMS spectrometer, presently under construction, details on the calorimeter design and accompanying GEANT4 simulation efforts are given. A Preshower+Shower design was selected as the most cost-effective among several design choices. The preshower will consist of a layer of 28 modules with TF-1 type lead glass radiators, stacked in two columns. The shower part will consist of 224 modules with F-101 type lead glass radiators, stacked in a “fly's eye” configuration of 14 columns and 16 rows. The active area of 120 × 130 cm 2 will encompass the beam envelope at the calorimeter. The anticipated performance of the new calorimeter is simulated over the full momentum range of the SHMS, predicting

  20. Outbreak of Cryptosporidium hominis following river flooding in the city of Halle (Saale), Germany, August 2013. (United States)

    Gertler, Maximilian; Dürr, Matthias; Renner, Peter; Poppert, Sven; Askar, Mona; Breidenbach, Janina; Frank, Christina; Preußel, Karina; Schielke, Anika; Werber, Dirk; Chalmers, Rachel; Robinson, Guy; Feuerpfeil, Irmgard; Tannich, Egbert; Gröger, Christine; Stark, Klaus; Wilking, Hendrik


    During weeks 32-33, 2013, 24 cases of cryptosporidiosis were notified in the city of Halle (annual mean 2008-2012: 9 cases). We investigated the outbreak to identify the source and recommend control measures, considering that between weeks 23-25 the river Saale which flows through the city centre overflowed the floodplain, parts of the city centre and damaged sewage systems. We defined a case as a resident of Halle with gastroenteritis, Cryptosporidium-positive stool and disease onset weeks 27 through 47. In a case-control study among kindergarten children, we compared cases and controls regarding environmental exposure, use of swimming pools, zoo visits and tap water consumption 14 days pre-onset or a corresponding 14-days-period (controls) and adjusted for residence. Stool specimens were tested by microscopy and PCR, and Cryptosporidium DNA was sequenced. Samples from public water system, swimming pools and river Saale were examined for Cryptosporidium oocysts (microscopy and PCR). Overall, 167 cases were detected, 40/167 (24%) were classified as secondary cases. First disease onsets occurred during week 29, numbers peaked in week 34 and started to decrease in week 36. Median age was 8 years (range: 0-77). Compared to controls (n = 61), cases (n = 20) were more likely to report visits to previously flooded areas (OR: 4.9; 95%-CI: 1.4-18) and the zoo (OR: 2.6; 95%-CI: 0.9-7.6). In multivariable analysis visits to the floodplain remained the sole risk factor (OR: 5.5; 95%-CI: 1.4-22). Only C.hominis of a single genotype (IbA9G2) was detected in stools. Oocysts were detected in samples from the river, two local lakes and three public swimming pools by microscopy, but not in the public water supply. Evidence suggests that activities in the dried out floodplain led to infection among children. Secondary transmissions may be involved. Consequently, authorities recommended to avoid playing, swimming and having picnics in the flood-affected area. Health

  1. Application Agreement and Integration Services (United States)

    Driscoll, Kevin R.; Hall, Brendan; Schweiker, Kevin


    Application agreement and integration services are required by distributed, fault-tolerant, safety critical systems to assure required performance. An analysis of distributed and hierarchical agreement strategies are developed against the backdrop of observed agreement failures in fielded systems. The documented work was performed under NASA Task Order NNL10AB32T, Validation And Verification of Safety-Critical Integrated Distributed Systems Area 2. This document is intended to satisfy the requirements for deliverable 5.2.11 under Task This report discusses the challenges of maintaining application agreement and integration services. A literature search is presented that documents previous work in the area of replica determinism. Sources of non-deterministic behavior are identified and examples are presented where system level agreement failed to be achieved. We then explore how TTEthernet services can be extended to supply some interesting application agreement frameworks. This document assumes that the reader is familiar with the TTEthernet protocol. The reader is advised to read the TTEthernet protocol standard [1] before reading this document. This document does not re-iterate the content of the standard.

  2. Quantum Hall effect in epitaxial graphene with permanent magnets (United States)

    Parmentier, F. D.; Cazimajou, T.; Sekine, Y.; Hibino, H.; Irie, H.; Glattli, D. C.; Kumada, N.; Roulleau, P.


    We have observed the well-kown quantum Hall effect (QHE) in epitaxial graphene grown on silicon carbide (SiC) by using, for the first time, only commercial NdFeB permanent magnets at low temperature. The relatively large and homogeneous magnetic field generated by the magnets, together with the high quality of the epitaxial graphene films, enables the formation of well-developed quantum Hall states at Landau level filling factors v = ±2, commonly observed with superconducting electro-magnets. Furthermore, the chirality of the QHE edge channels can be changed by a top gate. These results demonstrate that basic QHE physics are experimentally accessible in graphene for a fraction of the price of conventional setups using superconducting magnets, which greatly increases the potential of the QHE in graphene for research and applications.

  3. Noncommutative Field Theory and the Dynamics of Quantum Hall Fluids

    CERN Document Server

    Barbón, José L F


    We study the spectrum of density fluctuations of Fractional Hall Fluids in the context of the noncommutative hidrodynamical model of Susskind. We show that, within the weak-field expansion, the leading correction to the noncommutative Chern--Simons Lagrangian (a Maxwell term in the effective action,) destroys the incompressibility of the Hall fluid due to strong UV/IR effects at one loop. We speculate on possible relations of this instability with the transition to the Wigner crystal, and conclude that calculations within the weak-field expansion must be carried out with an explicit ultraviolet cutoff at the noncommutativity scale. We point out that the noncommutative dipoles exactly match the spatial structure of the Halperin--Kallin quasiexcitons. Therefore, we propose that the noncommutative formalism must describe accurately the spectrum at very large momenta, provided no weak-field approximations are made. We further conjecture that the noncommutative open Wilson lines are `vertex operators' for the quas...

  4. Anomalous Hall-like effect probe of antiferromagnetic domain wall. (United States)

    Lang, Lili; Qiu, Xuepeng; Zhou, Shiming


    Of crucial importance to antiferromagnetic (AF) spintronic devices, AF domain wall (AFDW), created in exchange biased Y 3 Fe 5 O 12 /Ni 0.50 Co 0.50 O (NiCoO)/Pt, is characterized by anomalous Hall-like effect through magnetic proximity effect and spin Hall magnetoresistance at NiCoO/Pt interface. The AFDW thickness, in the order of nanometers, has been for the first time proved in experiments to increase with increasing temperature. AF spins within AFDW show the same chirality in decent and ascent branches of ferromagnetic magnetization reversal process. Moreover, the uncompensated magnetic moment at the NiCoO/Pt interface is of perpendicular magnetization anisotropy and changes linearly in magnitude with temperature due to the reduced coordination of the magnetic atoms on the AF surface. This work will help to clarify the mechanism of the spin current propagation in AF materials and fully understand the physics behind exchange bias.

  5. Recent advances in the spin Hall effect of light (United States)

    Ling, Xiaohui; Zhou, Xinxing; Huang, Kun; Liu, Yachao; Qiu, Cheng-Wei; Luo, Hailu; Wen, Shuangchun


    The spin Hall effect (SHE) of light, as an analogue of the SHE in electronic systems, is a promising candidate for investigating the SHE in semiconductor spintronics/valleytronics, high-energy physics and condensed matter physics, owing to their similar topological nature in the spin-orbit interaction. The SHE of light exhibits unique potential for exploring the physical properties of nanostructures, such as determining the optical thickness, and the material properties of metallic and magnetic thin films and even atomically thin two-dimensional materials. More importantly, it opens a possible pathway for controlling the spin states of photons and developing next-generation photonic spin Hall devices as a fundamental constituent of the emerging spinoptics. In this review, based on the viewpoint of the geometric phase gradient, we give a detailed presentation of the recent advances in the SHE of light and its applications in precision metrology and future spin-based photonics.

  6. On the quantization of Hall currents in presence of disorder

    CERN Document Server

    Combes, J; Hislop, P


    We review recent results of two of the authors concerning the quantization of Hall currents, in particular a general quantization formula for the difference of edge Hall conductances in semi-infinite samples with and without a confining wall. We then study the case where the Fermi energy is located in a region of localized states and discuss new regularizations. We also sketch the proof of localization for 2D-models with constant magnetic field with random potential located in a half-plane in two different situations: 1) with a zero potential in the other half plane and for energies away from the Landau levels and 2) with a confining potential in the other half plane and on an interval of energies that covers an arbitrary number of Landau levels.

  7. Interaction-induced interference in the integer quantum Hall effect (United States)

    Sivan, I.; Bhattacharyya, R.; Choi, H. K.; Heiblum, M.; Feldman, D. E.; Mahalu, D.; Umansky, V.


    In recent interference experiments with an electronic Fabry-Pérot interferometer (FPI), implemented in the integer quantum Hall effect regime, a flux periodicity of h /2 e was observed at bulk fillings νB>2.5 . The halved periodicity was accompanied by an interfering charge e*=2 e , determined by shot-noise measurements. Here, we present measurements demonstrating that, counterintuitively, the coherence and the interference periodicity of the interfering chiral edge channel are solely determined by the coherence and the enclosed flux of the adjacent edge channel. Our results elucidate the important role of the latter and suggest that a neutral chiral edge mode plays a crucial role in the pairing phenomenon. Our findings reveal that the observed pairing of electrons is not a curious isolated phenomenon, but one of many manifestations of unexpected edge physics in the quantum Hall effect regime.

  8. Effects of Enhanced Eathode Electron Emission on Hall Thruster Operation

    International Nuclear Information System (INIS)

    Raitses, Y.; Smirnov, A.; Fisch, N.J.


    Interesting discharge phenomena are observed that have to do with the interaction between the magnetized Hall thruster plasma and the neutralizing cathode. The steadystate parameters of a highly ionized thruster discharge are strongly influenced by the electron supply from the cathode. The enhancement of the cathode electron emission above its self-sustained level affects the discharge current and leads to a dramatic reduction of the plasma divergence and a suppression of large amplitude, low frequency discharge current oscillations usually related to an ionization instability. These effects correlate strongly with the reduction of the voltage drop in the region with the fringing magnetic field between the thruster channel and the cathode. The measured changes of the plasma properties suggest that the electron emission affects the electron cross-field transport in the thruster discharge. These trends are generalized for Hall thrusters of various configurations.

  9. Exact law for homogeneous compressible Hall magnetohydrodynamics turbulence (United States)

    Andrés, N.; Galtier, S.; Sahraoui, F.


    We derive an exact law for three-dimensional (3D) homogeneous compressible isothermal Hall magnetohydrodynamic turbulence, without the assumption of isotropy. The Hall current is shown to introduce new flux and source terms that act at the small scales (comparable or smaller than the ion skin depth) to significantly impact the turbulence dynamics. The law provides an accurate means to estimate the energy cascade rate over a broad range of scales covering the magnetohydrodynamic inertial range and the sub-ion dispersive range in 3D numerical simulations and in in situ spacecraft observations of compressible turbulence. This work is particularly relevant to astrophysical flows in which small-scale density fluctuations cannot be ignored such as the solar wind, planetary magnetospheres, and the interstellar medium.

  10. Simulating Smoke Filling in Big Halls by Computational Fluid Dynamics

    Directory of Open Access Journals (Sweden)

    W. K. Chow


    Full Text Available Many tall halls of big space volume were built and, to be built in many construction projects in the Far East, particularly Mainland China, Hong Kong, and Taiwan. Smoke is identified to be the key hazard to handle. Consequently, smoke exhaust systems are specified in the fire code in those areas. An update on applying Computational Fluid Dynamics (CFD in smoke exhaust design will be presented in this paper. Key points to note in CFD simulations on smoke filling due to a fire in a big hall will be discussed. Mathematical aspects concerning of discretization of partial differential equations and algorithms for solving the velocity-pressure linked equations are briefly outlined. Results predicted by CFD with different free boundary conditions are compared with those on room fire tests. Standards on grid size, relaxation factors, convergence criteria, and false diffusion should be set up for numerical experiments with CFD.

  11. Error modelling of quantum Hall array resistance standards (United States)

    Marzano, Martina; Oe, Takehiko; Ortolano, Massimo; Callegaro, Luca; Kaneko, Nobu-Hisa


    Quantum Hall array resistance standards (QHARSs) are integrated circuits composed of interconnected quantum Hall effect elements that allow the realization of virtually arbitrary resistance values. In recent years, techniques were presented to efficiently design QHARS networks. An open problem is that of the evaluation of the accuracy of a QHARS, which is affected by contact and wire resistances. In this work, we present a general and systematic procedure for the error modelling of QHARSs, which is based on modern circuit analysis techniques and Monte Carlo evaluation of the uncertainty. As a practical example, this method of analysis is applied to the characterization of a 1 MΩ QHARS developed by the National Metrology Institute of Japan. Software tools are provided to apply the procedure to other arrays.

  12. Fractional Quantum Hall States in a Ge Quantum Well. (United States)

    Mironov, O A; d'Ambrumenil, N; Dobbie, A; Leadley, D R; Suslov, A V; Green, E


    Measurements of the Hall and dissipative conductivity of a strained Ge quantum well on a SiGe/(001)Si substrate in the quantum Hall regime are reported. We analyze the results in terms of thermally activated quantum tunneling of carriers from one internal edge state to another across saddle points in the long-range impurity potential. This shows that the gaps for different filling fractions closely follow the dependence predicted by theory. We also find that the estimates of the separation of the edge states at the saddle are in line with the expectations of an electrostatic model in the lowest spin-polarized Landau level (LL), but not in the spin-reversed LL where the density of quasiparticle states is not high enough to accommodate the carriers required.

  13. Precise quantization of anomalous Hall effect near zero magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Bestwick, A. J. [Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Fox, E. J. [Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Kou, Xufeng [Univ. of California, Los Angeles, CA (United States); Pan, Lei [Univ. of California, Los Angeles, CA (United States); Wang, Kang L. [Univ. of California, Los Angeles, CA (United States); Goldhaber-Gordon, D. [Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)


    In this study, we report a nearly ideal quantum anomalous Hall effect in a three-dimensional topological insulator thin film with ferromagnetic doping. Near zero applied magnetic field we measure exact quantization in the Hall resistance to within a part per 10,000 and a longitudinal resistivity under 1 Ω per square, with chiral edge transport explicitly confirmed by nonlocal measurements. Deviations from this behavior are found to be caused by thermally activated carriers, as indicated by an Arrhenius law temperature dependence. Using the deviations as a thermometer, we demonstrate an unexpected magnetocaloric effect and use it to reach near-perfect quantization by cooling the sample below the dilution refrigerator base temperature in a process approximating adiabatic demagnetization refrigeration.

  14. Performance of metal Hall sensors based on copper

    Czech Academy of Sciences Publication Activity Database

    Sentkerestiová, J.; Ďuran, Ivan; Kovařík, Karel; Viererbl, L.; Kohout, Michal


    Roč. 88, 6-8 (2013), s. 1310-1314 ISSN 0920-3796. [Symposium on Fusion Technology (SOFT-27)/27./. Liège, 24.09.2012-28.09.2012] R&D Projects: GA MŠk 7G10072; GA MŠk(CZ) LM2011021 Grant - others:EUROATOM(XE) FU07-CT-2007-00060 Institutional support: RVO:61389021 ; RVO:68378271 Keywords : Metal Hall sensor * Magnetic diagnostics * Copper Hall sensor * Fusion reactors * Neutron irradiation Subject RIV: BL - Plasma and Gas Discharge Physics; BM - Solid Matter Physics ; Magnetism (FZU-D) Impact factor: 1.149, year: 2013

  15. Matrix effective theories of the fractional quantum Hall effect

    International Nuclear Information System (INIS)

    Cappelli, Andrea; Rodriguez, Ivan D


    The present understanding of nonperturbative ground states in the fractional quantum Hall effect is based on effective theories of the Jain 'composite fermion' excitations. We review the approach based on matrix variables, i.e. D0 branes, originally introduced by Susskind and Polychronakos. We show that the Maxwell-Chern-Simons matrix gauge theory provides a matrix generalization of the quantum Hall effect, where the composite-fermion construction naturally follows from gauge invariance. The matrix ground states obtained by suitable projections of higher Landau levels are found to be in one-to-one correspondence with the Laughlin and Jain hierarchical states. The matrix theory possesses a physical limit for commuting matrices that could be reachable while staying in the same phase.

  16. Sensitivity of resistive and Hall measurements to local inhomogeneities

    DEFF Research Database (Denmark)

    Koon, Daniel W.; Wang, Fei; Petersen, Dirch Hjorth


    We derive exact, analytic expressions for the sensitivity of sheet resistance and Hall sheet resistance measurements to local inhomogeneities for the cases of nonzero magnetic fields, strong perturbations, and perturbations over a finite area, extending our earlier results on weak perturbations. ...... simulations on both a linear four-point probe array on a large circular disc and a van der Pauw square geometry. Furthermore, the results also agree well with Náhlík et al. published experimental results for physical holes in a circular copper foil disc.......We derive exact, analytic expressions for the sensitivity of sheet resistance and Hall sheet resistance measurements to local inhomogeneities for the cases of nonzero magnetic fields, strong perturbations, and perturbations over a finite area, extending our earlier results on weak perturbations. We...

  17. Fast micro Hall effect measurements on small pads

    DEFF Research Database (Denmark)

    Østerberg, Frederik Westergaard; Petersen, Dirch Hjorth; Nielsen, Peter F.


    Sheet resistance, carrier mobility, and sheet carrier density are important parameters in semiconductor production, and it is therefore important to be able to rapidly and accurately measure these parameters even on small samples or pads. The interpretation of four-point probe measurements on small...... pads is non-trivial. In this paper we discuss how conformal mapping can be used to evaluate theoretically expected measurement values on small pads. Theoretical values calculated from analytical mappings of simple geometries are compared to the values found from the numerical conformal mapping...... of a square onto the infinite half-plane, where well-established solutions are known. Hall effect measurements are performed to show, experimentally, that it is possible to measure Hall mobility in less than one minute on squares as small as 7070 lm2 with a deviation of 66.5% on a 1r level from accurate...

  18. Anomalous Hall effect and Nernst effect in itinerant ferromagnets

    International Nuclear Information System (INIS)

    Miyasato, T.; Abe, N.; Fujii, T.; Asamitsu, A.; Onose, Y.; Onoda, S.; Nagaosa, N.; Tokura, Y.


    Anomalous Hall effect (AHE) and anomalous Nernst effect (ANE) in many ferromagnetic metals including pure metals, oxides, and chalcogenides, are studied to obtain unified understandings of their origins. We show the universal behavior of anomalous Hall conductivity σ xy as a function of longitudinal conductivity σ xx over six orders of magnitude, which is well reproduced by a recent theory assuming both the intrinsic and extrinsic contributions to the AHE. ANE is closely related with AHE and gives us further information about the electronic state in the ground state of ferromagnets. The temperature dependence of transverse Peltier coefficient α xy shows almost similar behavior among various ferromagnets, and this behavior is expected from a conventional Boltzmann transport theory

  19. Anomalous Hall effect and Nernst effect in itinerant ferromagnets

    International Nuclear Information System (INIS)

    Asamitsu, A.; Miyasato, T.; Abe, N.; Fujii, T.; Onose, Y.; Onoda, S.; Nagaosa, N.; Tokura, Y.


    Anomalous Hall effect (AHE) and anomalous Nernst effect (ANE) in many ferromagnetic metals including pure metals, oxides, and calcogenides, are studied to obtain unified understandings of their origins. We show the universal behavior of anomalous Hall conductivity σ xy as a function of longitudinal conductivity σ xx over six orders of magnitude, which is well reproduced by rigorous unified theory assuming both intrinsic and extrinsic contributions to the AHE. ANE is closely related with AHE and gives us further information about the electronic state in the ground state of ferromagnets. The temperature dependence of transverse Peltier coefficient α xy shows almost similar behavior among various ferromagnets and this behavior is expected from a conventional Boltzmann transport theory

  20. Anomalous Hall effect scaling in ferromagnetic thin films

    KAUST Repository

    Grigoryan, Vahram L.


    We propose a scaling law for anomalous Hall effect in ferromagnetic thin films. Our approach distinguishes multiple scattering sources, namely, bulk impurity, phonon for Hall resistivity, and most importantly the rough surface contribution to longitudinal resistivity. In stark contrast to earlier laws that rely on temperature- and thickness-dependent fitting coefficients, this scaling law fits the recent experimental data excellently with constant parameters that are independent of temperature and film thickness, strongly indicating that this law captures the underlying physical processes. Based on a few data points, this scaling law can even fit all experimental data in full temperature and thickness range. We apply this law to interpret the experimental data for Fe, Co, and Ni and conclude that (i) the phonon-induced skew scattering is unimportant as expected; (ii) contribution from the impurity-induced skew scattering is negative; (iii) the intrinsic (extrinsic) mechanism dominates in Fe (Co), and both the extrinsic and intrinsic contributions are important in Ni.

  1. Theory of anomalous Hall effect in europium chalcogenides

    International Nuclear Information System (INIS)

    Sinkkonen, J.


    Considering the exchange interaction between the conduction electrons in a broad 5d-type band and the magnetic electrons in the localized 4f-shells, it is shown that in addition to the ordinary d-f exchange diagonal in band index, there is also a non-diagonal interaction representing a one particle transfer between the conduction and magnetic electrons. Including the spin-orbit coupling, an effective Hamiltonian for the conductionelectrons is obtained, which contains additional asymmetric scattering terms. The ordinary d-f exchange is treated as the dominating scattering interaction. The anomatous Hall effect results by skew scattering and side jump mechanisms. The density matrix method is used to derive the transport properties. The effect of the correlation of spins at different lattice sites is discussed. The model indicates that the anomatous Hall effect can be seen in heavily doped samples. (author)

  2. Quantum Hall effect in epitaxial graphene with permanent magnets. (United States)

    Parmentier, F D; Cazimajou, T; Sekine, Y; Hibino, H; Irie, H; Glattli, D C; Kumada, N; Roulleau, P


    We have observed the well-kown quantum Hall effect (QHE) in epitaxial graphene grown on silicon carbide (SiC) by using, for the first time, only commercial NdFeB permanent magnets at low temperature. The relatively large and homogeneous magnetic field generated by the magnets, together with the high quality of the epitaxial graphene films, enables the formation of well-developed quantum Hall states at Landau level filling factors v = ±2, commonly observed with superconducting electro-magnets. Furthermore, the chirality of the QHE edge channels can be changed by a top gate. These results demonstrate that basic QHE physics are experimentally accessible in graphene for a fraction of the price of conventional setups using superconducting magnets, which greatly increases the potential of the QHE in graphene for research and applications.

  3. Edge states in quantum Hall effect in graphene

    International Nuclear Information System (INIS)

    Gusynin, V.P.; Miransky, V.A.; Sharapov, S.G.; Shovkovy, I.A.


    We review recent results concerning the spectrum of edge states in the quantum Hall effect in graphene. In particular, special attention is paid to the derivation of the conditions under which gapless edge states exist in the spectrum of graphene with 'zigzag' and 'armchair' edges. It is found that in the case of a half-plane or a ribbon with zigzag edges, there are gapless edge states only when a spin gap dominates over a Dirac mass gap. In the case of a half-plane with an armchair edge, the existence of the gapless edge states depends on the specific type of Dirac mass gaps. The implications of these results for the dynamics in the quantum Hall effect in graphene are discussed

  4. Spin Hall effect-driven spin torque in magnetic textures

    KAUST Repository

    Manchon, Aurelien


    Current-induced spin torque and magnetization dynamics in the presence of spin Hall effect in magnetic textures is studied theoretically. The local deviation of the charge current gives rise to a current-induced spin torque of the form (1 - ΒM) × [(u 0 + αH u 0 M) ∇] M, where u0 is the direction of the injected current, H is the Hall angle and is the non-adiabaticity parameter due to spin relaxation. Since αH and ×can have a comparable order of magnitude, we show that this torque can significantly modify the current-induced dynamics of both transverse and vortex walls. © 2011 American Institute of Physics.

  5. On the low-field Hall coefficient of graphite

    Directory of Open Access Journals (Sweden)

    P. Esquinazi


    Full Text Available We have measured the temperature and magnetic field dependence of the Hall coefficient (RH in three, several micrometer long multigraphene samples of thickness between ∼9 to ∼30 nm in the temperature range 0.1 to 200 K and up to 0.2 T field. The temperature dependence of the longitudinal resistance of two of the samples indicates the contribution from embedded interfaces running parallel to the graphene layers. At low enough temperatures and fields RH is positive in all samples, showing a crossover to negative values at high enough fields and/or temperatures in samples with interfaces contribution. The overall results are compatible with the reported superconducting behavior of embedded interfaces in the graphite structure and indicate that the negative low magnetic field Hall coefficient is not intrinsic of the ideal graphite structure.

  6. Effect of quantum tunneling on spin Hall magnetoresistance. (United States)

    Ok, Seulgi; Chen, Wei; Sigrist, Manfred; Manske, Dirk


    We present a formalism that simultaneously incorporates the effect of quantum tunneling and spin diffusion on the spin Hall magnetoresistance observed in normal metal/ferromagnetic insulator bilayers (such as Pt/Y 3 Fe 5 O 12 ) and normal metal/ferromagnetic metal bilayers (such as Pt/Co), in which the angle of magnetization influences the magnetoresistance of the normal metal. In the normal metal side the spin diffusion is known to affect the landscape of the spin accumulation caused by spin Hall effect and subsequently the magnetoresistance, while on the ferromagnet side the quantum tunneling effect is detrimental to the interface spin current which also affects the spin accumulation. The influence of generic material properties such as spin diffusion length, layer thickness, interface coupling, and insulating gap can be quantified in a unified manner, and experiments that reveal the quantum feature of the magnetoresistance are suggested.

  7. Extraordinary Hall-effect in colloidal magnetic nanoparticle films

    Energy Technology Data Exchange (ETDEWEB)

    Ben Gur, Leah; Tirosh, Einat [School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801 (Israel); Segal, Amir [School of Physics, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801 (Israel); Markovich, Gil, E-mail: [School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801 (Israel); Gerber, Alexander, E-mail: [School of Physics, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801 (Israel)


    Colloidal nickel nanoparticles (NPs) coated with polyvinylpyrrolidone (PVP) were synthesized. The nanoparticle dispersions were deposited on substrates and dried under mild heating to form conductive films. The films exhibited very small coercivity, nearly metallic conductivity, and a significant extraordinary Hall effect signal. This method could be useful for preparing simple, printed magnetic field sensors with the advantage of relatively high sensitivity around zero magnetic field, in contrast to magnetoresistive sensors, which have maximal field sensitivity away from zero magnetic field. - Highlights: • Ni nanoparticle ink capable of forming conductive films on drying. • The Ni nanoparticle films exhibit significant extraordinary Hall effect. • This system could be used for preparing printed magnetic field sensors integrated in 3D printed structures.

  8. Admittance measurements in the quantum Hall effect regime

    Energy Technology Data Exchange (ETDEWEB)

    Hernández, C., E-mail: [Departamento de Física, Universidad Militar Nueva Granada, Carrera 11 # 101-80, Bogotá D.C. (Colombia); Laboratorio de Magnetismo, Departamento de Física, Universidad de los Andes, A.A. 4976, Bogotá D.C. (Colombia); Consejo, C.; Chaubet, C. [Laboratoire Charles Coulomb L2C, Université Montpellier II, Pl. E. Bataillon, 34095 Montpellier Cedex 5 (France)


    In this work we present an admittance study of a two-dimensional electron gas (2DEG) in the quantum Hall effect (QHE) regime. We have studied several Hall bars in different contacts configurations in the frequency range 100 Hz–1 MHz. Our interpretation is based on the Landauer–Büttiker theory and takes into account both the capacitance and the topology of the coaxial cables which are connected to the sample holder. We show that we always observe losses through the capacitive impedance of the coaxial cables, except in the two contacts configuration in which the cable capacitance does not influence the admittance measurement of the sample. In this case, we measure the electrochemical capacitance of the 2DEG and show its dependence with the filling factor ν.

  9. Valley Hall effect and Nernst effect in strain engineered graphene (United States)

    Niu, Zhi Ping; Yao, Jian-ming


    We theoretically predict the existence of tunneling valley Hall effect and Nernst effect in the normal/strain/normal graphene junctions, where a strained graphene is sandwiched by two normal graphene electrodes. By applying an electric bias a pure transverse valley Hall current with longitudinal charge current is generated. If the system is driven by a temperature bias, a valley Nernst effect is observed, where a pure transverse valley current without charge current propagates. Furthermore, the transverse valley current can be modulated by the Fermi energy and crystallographic orientation. When the magnetic field is further considered, we obtain a fully valley-polarized current. It is expected these features may be helpful in the design of the controllable valleytronic devices.

  10. Forced Hall magnetic reconnection: Parametric variation of the 'Newton Challenge'

    International Nuclear Information System (INIS)

    Huba, J.D.


    A parametric study of forced magnetic reconnection using a 2D Hall magnetohydrodynamic (MHD) code based on the 'Newton Challenge' is presented. The 'Newton Challenge' defined a magnetic reconnection problem in which reconnection was initiated by a spatially and temporally dependent inflow velocity on the upstream boundary. In this study the magnitude and time dependence of the inflow velocity are varied, as well as the length of the system and the boundary conditions. The general conclusion is that reconnection occurs sooner and faster for stronger impulsive drives (e.g., larger inflow velocities and longer time scales). The results are fairly insensitive to system length. Finally, the Hall MHD results are compared to results from a particle-in-cell simulation study

  11. Hall effect in quantum critical charge-cluster glass (United States)

    Wu, Jie; Bollinger, Anthony T.; Sun, Yujie


    Upon doping, cuprates undergo a quantum phase transition from an insulator to a d-wave superconductor. The nature of this transition and of the insulating state is vividly debated. Here, we study the Hall effect in La2-xSrxCuO4 (LSCO) samples doped near the quantum critical point at x ˜ 0.06. Dramatic fluctuations in the Hall resistance appear below TCG ˜ 1.5 K and increase as the sample is cooled down further, signaling quantum critical behavior. We explore the doping dependence of this effect in detail, by studying a combinatorial LSCO library in which the Sr content is varied in extremely fine steps, Δx ˜ 0.00008. We observe that quantum charge fluctuations wash out when superconductivity emerges but can be restored when the latter is suppressed by applying a magnetic field, showing that the two instabilities compete for the ground state.

  12. Nursing home resident quality of life: testing for measurement equivalence across resident, family, and staff perspectives. (United States)

    Godin, Judith; Keefe, Janice; Kelloway, E Kevin; Hirdes, John P


    This study explores the factor structure of the interRAI self-report nursing home quality of life survey and develops a measure that will allow researchers to compare predictors of quality of life (QOL) across resident, family, and staff perspectives. Nursing home residents (N = 319), family members (N = 397), and staff (N = 862) were surveyed about their perceptions of resident QOL. Exploratory factor analyses were conducted on a random half of the staff data. Subsequently, confirmatory factor analysis was used to test for measurement equivalence across the three perspectives. The final model had a four-factor structure (i.e., care and support, food, autonomy, and activities) across all three perspectives. Each factor had at least two items that were equivalent across all three perspectives, which suggests at least partial measurement equivalence. The finding of partial measurement equivalence acknowledges there are important differences between perspectives and provides a tool that researchers can use to compare predictors of QOL, but not levels of agreement across perspectives. Targeting these four aspects is likely to have the additional benefit of improving family and staff perceptions of resident QOL in addition to the resident's own QOL.

  13. Leadership Training in Otolaryngology Residency. (United States)

    Bent, John P; Fried, Marvin P; Smith, Richard V; Hsueh, Wayne; Choi, Karen


    Although residency training offers numerous leadership opportunities, most residents are not exposed to scripted leadership instruction. To explore one program's attitudes about leadership training, a group of otolaryngology faculty (n = 14) and residents (n = 17) was polled about their attitudes. In terms of self-perception, more faculty (10 of 14, 71.4%) than residents (9 of 17, 52.9%; P = .461) considered themselves good leaders. The majority of faculty and residents (27 of 31) thought that adults could be taught leadership ability. Given attitudes about leadership ability and the potential for improvement through instruction, consideration should be given to including such training in otolaryngology residency.

  14. Data handling for the wide-angle hall jet experiment

    International Nuclear Information System (INIS)

    Cassel, D.; Engelmann, R.; Gordon, H.; Grannis, P.; Mallik, U.; Meadows, B.; Morris, T.; Plano, R.; Saulys, A.; Stein, S.


    The data handling needs for a jet production experiment in the wide-angle hall are discussed. The several layers of triggering and a data acquisition system were designed, the configuration of the local intersection computer system was discussed, and the time required to analyze a typical event was estimated. It was concluded that the experiment does not appear to place unrealistic demands on detector technology. The slow trigger was believed to be the crucial aspect of the experiment. 15 figures, 1 tables

  15. Tunneling between edge states in a quantum spin Hall system. (United States)

    Ström, Anders; Johannesson, Henrik


    We analyze a quantum spin Hall device with a point contact connecting two of its edges. The contact supports a net spin tunneling current that can be probed experimentally via a two-terminal resistance measurement. We find that the low-bias tunneling current and the differential conductance exhibit scaling with voltage and temperature that depend nonlinearly on the strength of the electron-electron interaction.

  16. Design and Operation of Hall Thruster with Segmented Electrodes

    International Nuclear Information System (INIS)

    Litvak, A.A.; Dorf, L.A.; Fisch, N.J.; Raitses, Y.


    Principles of the Hall thruster with segmented electrodes are explored. A suitable vacuum facility was put into service. For purposes of comparison between segmented and conventional thruster approaches, a modular laboratory prototype thruster was designed and built. Under conventional operation, the thruster achieves state-of-the-art efficiencies (56% at 300 V and 890 W). Very preliminary results under operation with segmented electrodes are also described

  17. Preliminary Study of Arcjet Neutralization of Hall Thruster Clusters (Postprint) (United States)


    report on fundamental experiments to understand how much electron current can be drawn to a surrogate anode from the plume of low power arcjets ...operating on hydrogen and helium, and then demonstrate the first successful operation of a low power Hall thruster- arcjet neutralizer package. In the...concept demonstration. The arcjet operated at very low powers (~ 70-120W) on helium, at a mass flow rate of 4.5 mg/s, and was able to effectively

  18. Inverse Spin Hall Effect in SNS Josephson Junctions


    Mal'shukov, A. G.; Sadjina, Severin; Brataas, Arne


    We consider DC supercurrents in SNS junctions. Spin-orbit coupling in combination with Zeeman fields can induce an effective vector potential in the normal conductor. As a consequence, an out-of-plane spin-density varying along the transverse direction causes a longitudinal phase difference between the superconducting terminals. The resulting equilibrium phase coherent supercurrent is analogue to the non-equilibrium inverse spin Hall effect in normal conductors. We explicitly compute the effe...

  19. Options for Energy Upgrade of the Hall B Tagger

    International Nuclear Information System (INIS)

    H. Crannell; D. Sober


    Four options for an energy upgrade of the present Hall-B Tagger have been considered. These are: (1) Boost the magnetic field in the present Tagger; (2) Replace the Tagger with a new Tagger system; (3) Install a pre-Tagger magnetic chacain, and (4) Use the present Tagger as part of the beam dump. In this document each of these options is described briefly, the advantages and disadvantages of each are presented, and a very rough cost of implementation is suggested

  20. Pseudospectral Model for Hybrid PIC Hall-effect Thruster Simulation (United States)


    an axial-azimuthal hybrid-PIC HET code is under development, initially with a reduced set of physics. In particular, dynamic ionization is ignored...Approved for public release; distribution unlimited. 412 TW/PAO Clearance No. 15306 xenon only) is with PIC and the electron description is as a...Bilyeu, D., and Tran, J., “ Dynamic Particle Weight Remapping in Hybrid PIC Hall-effect Thruster Simulation,” 34th Int. Electric Propulsion Conf

  1. Resistive mode in rotating plasma columns including the hall current

    International Nuclear Information System (INIS)

    Galvao, R.M.O.


    A new resistive mode is shown to exist in rotating plasma columns. The mode is localized in the neighbourhood of the radius where the angular velocity of the bulk plasma is equal to minus half the local angular velocity of the ions. This singular point is caused by the Hall term in the generalized Ohm law. The growth rate of the mode scales with eta sup(1/2), where eta is the plasma resistivity. (Author) [pt

  2. Hall Effect Influence on a Highly Conducting Fluid

    Energy Technology Data Exchange (ETDEWEB)

    Witalis, E.A.


    The properties of an incompressible perfect fluid exhibiting Hall effect is investigated in the limit of infinite electrical conductivity and mobility. The magnetic field strength and the fluid velocity are found to obey the equations B = {mu}{rho}/{sigma} x curlV and V -{mu}/({sigma}{mu}{sub 0}) x curlB (MKS units) where {rho}, {sigma} and {mu} denote mass density, conductivity and charge carrier mobility. Some physical interpretations and applications are given.

  3. Effet Hall quantique, liquides de Luttinger et charges fractionnaires (United States)

    Roche, Patrice; Rodriguez, V.; Glattli, D. Christian

    We review some basic properties of the Fractional Quantum Hall Effect and particularly address the physics of the edge states. The chiral Luttinger liquid properties of the edges are discussed and probed experimentally using transport measurements. Shot noise measurements, which allow determination of the quasiparticle charge are also discussed. To cite this article: P. Roche et al., C. R. Physique 3 (2002) 717-732.

  4. Two-dimensional Ising physics in quantum Hall ferromagnets

    Czech Academy of Sciences Publication Activity Database

    Jungwirth, Tomáš; MacDonald, A. H.; Rezayi, E. H.


    Roč. 12, - (2002), s. 1-7 ISSN 1386-9477 R&D Projects: GA ČR GA202/01/0754; GA MŠk OC 514.10 Institutional research plan: CEZ:AV0Z1010914 Keywords : quantum Hall ferromagnets * higher Landau levels * domain walls Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.107, year: 2002

  5. Focused ion beam patterned Hall nano-sensors

    International Nuclear Information System (INIS)

    Candini, A.; Gazzadi, G.C.; Di Bona, A.; Affronte, M.; Ercolani, D.; Biasiol, G.; Sorba, L.


    By means of focused ion beam milling, we fabricate Hall magnetometers with active areas as small as 100x100nm 2 . The constituent material can either be metallic (Au), semimetallic (Bi) or doped bulk semiconducting (Si doped GaAs). We experimentally show that Au nano-probes can work from room temperature down to liquid helium with magnetic flux sensitivity -1 Φ 0

  6. Measurement of Safety Factor Using Hall Probes on CASTOR Tokamak

    Czech Academy of Sciences Publication Activity Database

    Kovařík, Karel; Ďuran, Ivan; Bolshakova, I.; Holyaka, R.; Erashok, V.


    Roč. 56, suppl.B (2006), s. 104-110 ISSN 0011-4626. [Symposium on Plasma Physics and Technology/22nd./. Praha, 26.6.2006-29.6.2006] R&D Projects: GA AV ČR(CZ) KJB100430504 Institutional research plan: CEZ:AV0Z20430508 Keywords : Plasma * tokamak * safety factor * hall probe Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.568, year: 2006

  7. Perceptual Assessment of Velopharyngeal Dysfunction by Otolaryngology Residents. (United States)

    Butts, Sydney C; Truong, Alan; Forde, Christina; Stefanov, Dimitre G; Marrinan, Eileen


    To assess the ability of otolaryngology residents to rate the hypernasal resonance of patients with velopharyngeal dysfunction. We hypothesize that experience (postgraduate year [PGY] level) and training will result in improved ratings of speech samples. Prospective cohort study. Otolaryngology training programs at 2 academic medical centers. Thirty otolaryngology residents (PGY 1-5) were enrolled in the study. All residents rated 30 speech samples at 2 separate times. Half the residents completed a training module between the rating exercises, with the other half serving as a control group. Percentage agreement with the expert rating of each speech sample and intrarater reliability were calculated for each resident. Analysis of covariance was used to model accuracy at session 2. The median percentage agreement at session 1 was 53.3% for all residents. At the second session, the median scores were 53.3% for the control group and 60% for the training group, but this difference was not statistically significant. Intrarater reliability was moderate for both groups. Residents were more accurate in their ratings of normal and severely hypernasal speech. There was no correlation between rating accuracy and PGY level. Score at session 1 positively correlated with score at session 2. Perceptual training of otolaryngology residents has the potential to improve their ratings of hypernasal speech. Length of time in residency may not be best predictor of perceptual skill. Training modalities incorporating practice with hypernasal speech samples could improve rater skills and should be studied more extensively. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2016.

  8. Parametric studies of the Hall Thruster at Soreq

    International Nuclear Information System (INIS)

    Ashkenazy, J.; Rattses, Y.; Appelbaum, G.


    An electric propulsion program was initiated at Soreq a few years ago, aiming at the research and development of advanced Hall thrusters for various space applications. The Hall thruster accelerates a plasma jet by an axial electric field and an applied radial magnetic field in an annular ceramic channel. A relatively large current density (> 0.1 A/cm 2 ) can be obtained, since the acceleration mechanism is not limited by space charge effects. Such a device can be used as a small rocket engine onboard spacecraft with the advantage of a large jet velocity compared with conventional rocket engines (10,000-30,000 m/s vs. 2,000-4,800 m/s). An experimental Hall thruster was constructed at Soreq and operated under a broad range of operating conditions and under various configurational variations. Electrical, magnetic and plasma diagnostics, as well as accurate thrust and gas flow rate measurements, have been used to investigate the dependence of thruster behavior on the applied voltage, gas flow rate, magnetic field, channel geometry and wall material. Representative results highlighting the major findings of the studies conducted so far are presented

  9. Quantum Entanglement and the Topological Order of Fractional Hall States (United States)

    Rezayi, Edward


    Fractional quantum Hall states or, more generally, topological phases of matter defy Landau classification based on order parameter and broken symmetry. Instead they have been characterized by their topological order. Quantum information concepts, such as quantum entanglement, appear to provide the most efficient method of detecting topological order solely from the knowledge of the ground state wave function. This talk will focus on real-space bi-partitioning of quantum Hall states and will present both exact diagonalization and quantum Monte Carlo studies of topological entanglement entropy in various geometries. Results on the torus for non-contractible cuts are quite rich and, through the use of minimum entropy states, yield the modular S-matrix and hence uniquely determine the topological order, as shown in recent literature. Concrete examples of minimum entropy states from known quantum Hall wave functions and their corresponding quantum numbers, used in exact diagonalizations, will be given. In collaboration with Clare Abreu and Raul Herrera. Supported by DOE Grant DE-SC0002140.

  10. Precision Electron Beam Polarimetry in Hall C at Jefferson Lab (United States)

    Gaskell, David


    The electron beam polarization in experimental Hall C at Jefferson Lab is measured using two devices. The Hall-C/Basel Møller polarimeter measures the beam polarization via electron-electron scattering and utilizes a novel target system in which a pure iron foil is driven to magnetic saturation (out of plane) using a superconducting solenoid. A Compton polarimeter measures the polarization via electron-photon scattering, where the photons are provided by a high-power, CW laser coupled to a low gain Fabry-Perot cavity. In this case, both the Compton-scattered electrons and backscattered photons provide measurements of the beam polarization. Results from both polarimeters, acquired during the Q-Weak experiment in Hall C, will be presented. In particular, the results of a test in which the Møller and Compton polarimeters made interleaving measurements at identical beam currents will be shown. In addition, plans for operation of both devices after completion of the Jefferson Lab 12 GeV Upgrade will also be discussed.

  11. Mission and System Advantages of Iodine Hall Thrusters (United States)

    Dankanich, John W.; Szabo, James; Pote, Bruce; Oleson, Steve; Kamhawi, Hani


    The exploration of alternative propellants for Hall thrusters continues to be of interest to the community. Investments have been made and continue for the maturation of iodine based Hall thrusters. Iodine testing has shown comparable performance to xenon. However, iodine has a higher storage density and resulting higher ?V capability for volume constrained systems. Iodine's vapor pressure is low enough to permit low-pressure storage, but high enough to minimize potential adverse spacecraft-thruster interactions. The low vapor pressure also means that iodine does not condense inside the thruster at ordinary operating temperatures. Iodine is safe, it stores at sub-atmospheric pressure, and can be stored unregulated for years on end; whether on the ground or on orbit. Iodine fills a niche for both low power (10kW) electric propulsion regimes. A range of missions have been evaluated for direct comparison of Iodine and Xenon options. The results show advantages of iodine Hall systems for both small and microsatellite application and for very large exploration class missions.

  12. Paired quantum Hall states on noncommutative two-tori

    Energy Technology Data Exchange (ETDEWEB)

    Marotta, Vincenzo [Dipartimento di Scienze Fisiche, Universita di Napoli ' Federico II' and INFN, Sezione di Napoli, Compl. universitario M. Sant' Angelo, Via Cinthia, 80126 Napoli (Italy); Naddeo, Adele, E-mail: naddeo@sa.infn.i [CNISM, Unita di Ricerca di Salerno and Dipartimento di Fisica ' E. R. Caianiello' , Universita degli Studi di Salerno, Via Salvador Allende, 84081 Baronissi (Italy)


    By exploiting the notion of Morita equivalence for field theories on noncommutative tori and choosing rational values of the noncommutativity parameter theta (in appropriate units), a one-to-one correspondence between an Abelian noncommutative field theory (NCFT) and a non-Abelian theory of twisted fields on ordinary space can be established. Starting from this general result, we focus on the conformal field theory (CFT) describing a quantum Hall fluid (QHF) at paired states fillings nu=m/(pm+2) Cristofano et al. (2000) , recently obtained by means of m-reduction procedure, and show that it is the Morita equivalent of a NCFT. In this way we extend the construction proposed in Marotta and Naddeo (2008) for the Jain series nu=m/(2pm+1) . The case m=2 is explicitly discussed and the role of noncommutativity in the physics of quantum Hall bilayers is emphasized. Our results represent a step forward the construction of a new effective low energy description of certain condensed matter phenomena and help to clarify the relationship between noncommutativity and quantum Hall fluids.

  13. An edge index for the quantum spin-Hall effect

    International Nuclear Information System (INIS)

    Prodan, Emil


    Quantum spin-Hall systems are topological insulators displaying dissipationless spin currents flowing at the edges of the samples. In contradistinction to the quantum Hall systems where the charge conductance of the edge modes is quantized, the spin conductance is not and it remained an open problem to find the observable whose edge current is quantized. In this paper, we define a particular observable and the edge current corresponding to this observable. We show that this current is quantized and that the quantization is given by the index of a certain Fredholm operator. This provides a new topological invariant that is shown to take the generic values 0 and 2, in line with the Z 2 topological classification of time-reversal invariant systems. The result gives an effective tool for the investigation of the edge structure in quantum spin-Hall systems. Based on a reasonable assumption, we also show that the edge conducting channels are not destroyed by a random edge. (fast track communication)

  14. Giant anisotropic magnetoresistance in a quantum anomalous Hall insulator (United States)

    Kandala, Abhinav; Richardella, Anthony; Kempinger, Susan; Liu, Chao-Xing; Samarth, Nitin


    When a three-dimensional ferromagnetic topological insulator thin film is magnetized out-of-plane, conduction ideally occurs through dissipationless, one-dimensional (1D) chiral states that are characterized by a quantized, zero-field Hall conductance. The recent realization of this phenomenon, the quantum anomalous Hall effect, provides a conceptually new platform for studies of 1D transport, distinct from the traditionally studied quantum Hall effects that arise from Landau level formation. An important question arises in this context: how do these 1D edge states evolve as the magnetization is changed from out-of-plane to in-plane? We examine this question by studying the field-tilt-driven crossover from predominantly edge-state transport to diffusive transport in Crx(Bi,Sb)2−xTe3 thin films. This crossover manifests itself in a giant, electrically tunable anisotropic magnetoresistance that we explain by employing a Landauer–Büttiker formalism. Our methodology provides a powerful means of quantifying dissipative effects in temperature and chemical potential regimes far from perfect quantization. PMID:26151318

  15. Hall Effect in Bulk-Doped Organic Single Crystals. (United States)

    Ohashi, Chika; Izawa, Seiichiro; Shinmura, Yusuke; Kikuchi, Mitsuru; Watase, Seiji; Izaki, Masanobu; Naito, Hiroyoshi; Hiramoto, Masahiro


    The standard technique to separately and simultaneously determine the carrier concentration per unit volume (N, cm -3 ) and the mobility (μ) of doped inorganic single crystals is to measure the Hall effect. However, this technique has not been reported for bulk-doped organic single crystals. Here, the Hall effect in bulk-doped single-crystal organic semiconductors is measured. A key feature of this work is the ultraslow co-deposition technique, which reaches as low as 10 -9 nm s -1 and enables us to dope homoepitaxial organic single crystals with acceptors at extremely low concentrations of 1 ppm. Both the hole concentration per unit volume (N, cm -3 ) and the Hall mobility (μ H ) of bulk-doped rubrene single crystals, which have a band-like nature, are systematically observed. It is found that these rubrene single crystals have (i) a high ionization rate and (ii) scattering effects because of lattice disturbances, which are peculiar to this organic single crystal. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Stability of the Hall sensors performance under neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Duran, I.; Hron, M.; Stockel, J. [Institute of Plasma Physics, Association EURATOM/IPP.CR, Praha (Czech Republic); Viererbl, L.; Vsolak, R.; Cerva, V. [Nuclear Research Institute plc (Czech Republic); Bolshakova, I.; Holyaka, R. [Lviv Polytechnic National Univ. (Ukraine); Vayakis, G. [ITER International Team, Naka Joint Work Site, Naka, Ibaraki (Japan)


    A principally new diagnostic method must be developed for magnetic measurements in steady state regime of operation of fusion reactor. One of the options is the use of transducers based on Hall effect. The use of Hall sensors in ITER is presently limited by their questionable radiation and thermal stability. Issues of reliable operation in ITER like radiation and thermal environment are addressed in the paper. The results of irradiation tests of candidate Hall sensors in LVR-15 and IBR-2 experimental fission reactors are presented. Stable operation (deterioration of sensitivity below one percent) of the specially prepared sensors was demonstrated during irradiation by the total fluence of 3.10{sup 16} n/cm{sup 2} in IBR-2 reactor. Increasing the total neutron fluence up to 3.10{sup 17} n/cm{sup 2} resulted in deterioration of the best sensor's output still below 10% as demonstrated during irradiation in LVR-15 fission reactor. This level of neutron is already higher than the expected ITER life time neutron fluence for a sensor location just outside the ITER vessel. (authors)

  17. Dynamical quantum Hall effect in the parameter space. (United States)

    Gritsev, V; Polkovnikov, A


    Geometric phases in quantum mechanics play an extraordinary role in broadening our understanding of fundamental significance of geometry in nature. One of the best known examples is the Berry phase [M.V. Berry (1984), Proc. Royal. Soc. London A, 392:45], which naturally emerges in quantum adiabatic evolution. So far the applicability and measurements of the Berry phase were mostly limited to systems of weakly interacting quasi-particles, where interference experiments are feasible. Here we show how one can go beyond this limitation and observe the Berry curvature, and hence the Berry phase, in generic systems as a nonadiabatic response of physical observables to the rate of change of an external parameter. These results can be interpreted as a dynamical quantum Hall effect in a parameter space. The conventional quantum Hall effect is a particular example of the general relation if one views the electric field as a rate of change of the vector potential. We illustrate our findings by analyzing the response of interacting spin chains to a rotating magnetic field. We observe the quantization of this response, which we term the rotational quantum Hall effect.

  18. Typology of Retractable Roof Structures in Stadiums and Sports Halls

    Directory of Open Access Journals (Sweden)

    Andrej Mahovič


    Full Text Available Retractable roof structures are one of the four fundamental systems (in addition to the playing area, stands and facade in a stadium and sports hall. The roof protects users against various weather conditions and creates optimum circumstances for carrying out different activities. Stadiums and sports halls with retractable roof structures can host a greater variety of activities, improve the quality of their implementation and the quality of visitors’ experience, and affect the perception and experience of people using or observing such buildings. A retractable roof structure allows for natural lighting and ventilation of the venue, gives optimal conditions for grass growth on the playing field, and reduces costs of use and maintenance of the building. Different typologies of movement of roof structures (frequency of opening and closing, design of the structure, and methods of movement are categorised in terms of their architectural and structural design. Application of different retractable roof systems worldwide is indicator of their effectiveness and efficiency, and is basis for use of movement also in other fundamental systems of stadiums and sports halls. Research and identification of characteristics of retractable roof structures lead to the design of new moving systems that can with the application of the moving principle change the purpose of movable elements or assume the characteristics of other fundamental systems.


    Bekker, Marthinus J; Cumming, Tania D; Osborne, Nikola K.P; Bruining, Angela M; McClean, Julia I; Leland, Louis S


    This experiment investigated the combined use of visual prompts, daily feedback, and rewards to reduce electricity consumption in a university residential hall. After a 17-day baseline period, the experimental intervention was introduced in the intervention hall, and no change was made in the control hall. Energy usage decreased in the intervention hall, but energy usage did not change appreciably in the control hall. In the intervention hall, mean daytime and nighttime savings were 16.2% and 10.7%, respectively, compared to savings of 3.8% (day) and 6.5% (night) in the control hall. PMID:21119909

  20. Hall current and joule heating effects on free convection flow of a nanofluid over a vertical cone in presence of thermal radiation

    Directory of Open Access Journals (Sweden)

    Abbas Wael


    Full Text Available The effects of Hall current and Joule heating on flow and heat transfer of a nanofluid along a vertical cone in the presence of thermal radiation is considered. The flow is subjected to a uniform strong transverse magnetic field normal to the cone surface. Similarity transformations are used to convert the non-linear boundary- layer equations for momentum and energy equations to a system of non-linear ordinary differential equations which are then solved numerically with appropriate boundary conditions. The solutions are presented in terms of local skin friction, local Nusselt number, velocity, and temperature profiles for values of magnetic parameter, Hall parameter, Eckert number, radiation parameter, and nanoparticle volume fraction. Comparison of the numerical results made with previously published results under the special cases, the results are found to be in an excellent agreement. It is also found that, nanoparticle volume fraction parameter and types of nanofluid play an important role to significantly determine the flow behavior.

  1. Meeting the needs of the resident trainee during an elective subspecialty rotation. (United States)

    Hale, Andrew; Glassman, Rebecca; Fessler, David; Mukamal, Kenneth J; Stead, Wendy


    To examine and compare perceptions between resident-trainees and faculty-educators on goals and reasons why resident trainees choose certain subspecialty elective rotations. In June 2013 residents and faculty-educators at a large tertiary care academic medical center were surveyed regarding perceived resident goals for subspecialty electives. Each group was sent a different electronic survey of parallel questions assessing agreement on an ordered scale with statements about which factors impacted resident choice. The survey was sent to 154 residents and had 75 (49%) respondents, as well as 20 faculty-educators with 12 (60%) respondents. Residents and faculty did not differ in their responses that electives were chosen to fill perceived knowledge gaps (exact Cochran-Armitage p = .51). However, educators and residents significantly varied in the degree to which they thought resident choice was based on networking within the field (exact Cochran-Armitage p = .01), auditioning for fellowship (exact Cochran-Armitage p < .01), or exploring career options (exact Cochran-Armitage p = .01), with educators overestimating the degree to which these impacted resident choice. Resident trainees and faculty educators agree that subspecialty electives are most frequently chosen in order to meet resident educational goals, highlighting the importance of developing and delivering high quality subspecialty curricular content for the internal medicine resident learner during electives. Many residents choose electives for career development reasons, but faculty educators overestimate this motivation.

  2. Study on mechanics of bodies under the action of sound pollution in industrial halls. Part II: Analysis of sound pressure inside the hall (United States)

    Arghir, M.; Lăpuşan, I. L.


    In this work, it is taking into account all these phenomena of sounds propagation in given space. Within the framework of the given research is a study in industrial park "Teraplast" from Bistriţa-Năsăud county. This is industrial products for pvc constructions. From the submissions made to the workshops of processing industrial park "Teraplast" has been found, that noise is produced mainly in the power pumps hall. The registrations were made during a normal working days. The recorders made, for one minute, with recorder (NL32, Japanese society RION) in the pump's hall 12 positions were introduced in a high- capacity computer. This second part of the paper contains a natural continuation of the study conducted in the first part. Through the composition of sound waves for each pump in part according to the construction of the hall, gives the sound field generated by sources of power pumps during simultaneous operation. Field of noise sources inside the hall of power pumps determines an acoustic pressure on the walls of the hall. Taking into consideration the frequencies that are threatening the construction of the hall, will be presented successively acoustic pressure what special expertise to the hall walls the pressures of 230Hz, 350Hz, 800Hz and 1400Hz. This study is important for the acoustic pressure made from the "Teraplast" enterprise inside, and outside the halls.

  3. Strong anisotropic anomalous Hall effect and spin Hall effect in the chiral antiferromagnetic compounds Mn3X (X =Ge , Sn, Ga, Ir, Rh, and Pt) (United States)

    Zhang, Yang; Sun, Yan; Yang, Hao; Železný, Jakub; Parkin, Stuart P. P.; Felser, Claudia; Yan, Binghai


    We have carried out a comprehensive study of the intrinsic anomalous Hall effect and spin Hall effect of several chiral antiferromagnetic compounds Mn3X (X = Ge, Sn, Ga, Ir, Rh and Pt) by ab initio band structure and Berry phase calculations. These studies reveal large and anisotropic values of both the intrinsic anomalous Hall effect and spin Hall effect. The Mn3X materials exhibit a noncollinear antiferromagnetic order which, to avoid geometrical frustration, forms planes of Mn moments that are arranged in a Kagome-type lattice. With respect to these Kagome planes, we find that both the anomalous Hall conductivity (AHC) and the spin Hall conductivity (SHC) are quite anisotropic for any of these materials. Based on our calculations, we propose how to maximize AHC and SHC for different materials. The band structures and corresponding electron filling, that we show are essential to determine the AHC and SHC, are compared for these different compounds. We point out that Mn3Ga shows a large SHC of about 600 (ℏ /e ) (Ωcm) -1 . Our work provides insights into the realization of strong anomalous Hall effects and spin Hall effects in chiral antiferromagnetic materials.

  4. Lawful Permanent Residents - Annual Report (United States)

    Department of Homeland Security — A lawful permanent resident (LPR) or 'green card' recipient is defined by immigration law as a person who has been granted lawful permanent residence in the United...

  5. Experiments on Quantum Hall Topological Phases in Ultra Low Temperatures

    International Nuclear Information System (INIS)

    Du, Rui-Rui


    This project is to cool electrons in semiconductors to extremely low temperatures and to study new states of matter formed by low-dimensional electrons (or holes). At such low temperatures (and with an intense magnetic field), electronic behavior differs completely from ordinary ones observed at room temperatures or regular low temperature. Studies of electrons at such low temperatures would open the door for fundamental discoveries in condensed matter physics. Present studies have been focused on topological phases in the fractional quantum Hall effect in GaAs/AlGaAs semiconductor heterostructures, and the newly discovered (by this group) quantum spin Hall effect in InAs/GaSb materials. This project consists of the following components: 1) Development of efficient sample cooling techniques and electron thermometry: Our goal is to reach 1 mK electron temperature and reasonable determination of electron temperature; 2) Experiments at ultra-low temperatures: Our goal is to understand the energy scale of competing quantum phases, by measuring the temperature-dependence of transport features. Focus will be placed on such issues as the energy gap of the 5/2 state, and those of 12/5 (and possible 13/5); resistive signature of instability near 1/2 at ultra-low temperatures; 3) Measurement of the 5/2 gaps in the limit of small or large Zeeman energies: Our goal is to gain physics insight of 5/2 state at limiting experimental parameters, especially those properties concerning the spin polarization; 4) Experiments on tuning the electron-electron interaction in a screened quantum Hall system: Our goal is to gain understanding of the formation of paired fractional quantum Hall state as the interaction pseudo-potential is being modified by a nearby screening electron layer; 5) Experiments on the quantized helical edge states under a strong magnetic field and ultralow temperatures: our goal is to investigate both the bulk and edge states in a quantum spin Hall insulator under

  6. Finite element and network electrical simulation of rotating magnetofluid flow in nonlinear porous media with inclined magnetic field and hall currents

    Directory of Open Access Journals (Sweden)

    Bég Anwar O.


    Full Text Available A mathematical model is presented for viscous hydromagnetic flow through a hybrid non-Darcy porous media rotating generator. The system is simulated as steady, incompressible flow through a nonlinear porous regime intercalated between parallel plates of the generator in a rotating frame of reference in the presence of a strong, inclined magnetic field A pressure gradient term is included which is a function of the longitudinal coordinate. The general equations for rotating viscous magnetohydrodynamic flow are presented and neglecting convective acceleration effects, the two-dimensional viscous flow equations are derived incorporating current density components, porous media drag effects, Lorentz drag force components and Hall current effects. Using an appropriate group of dimensionless variables, the momentum equations for primary and secondary flow are rendered nondimensional and shown to be controlled by six physical parameters-Hartmann number (Ha, Hall current parameter (Nh, Darcy number (Da, Forchheimer number (Fs, Ekman number (Ek and dimensionless pressure gradient parameter (Np, in addition to one geometric parameter-the orientation of the applied magnetic field (θ . Several special cases are extracted from the general model, including the non-porous case studied earlier by Ghosh and Pop (2006. A numerical solution is presented to the nonlinear coupled ordinary differential equations using both the Network Simulation Method and Finite Element Method, achieving excellent agreement. Additionally very good agreement is also obtained with the earlier analytical solutions of Ghosh and Pop (2006. for selected Ha, Ek and Nh values. We examine in detail the effects of magnetic field, rotation, Hall current, bulk porous matrix drag, second order porous impedance, pressure gradient and magnetic field inclination on primary and secondary velocity distributions and also frictional shear stresses at the plates. Primary velocity is seen to decrease

  7. On limitations of laser-induced fluorescence diagnostics for xenon ion velocity distribution function measurements in Hall thrusters (United States)

    Romadanov, I.; Raitses, Y.; Diallo, A.; Hara, K.; Kaganovich, I. D.; Smolyakov, A.


    Hall thruster operation is characterized by strong breathing oscillations of the discharge current, the plasma density, the temperature, and the electric field. Probe- and laser-induced fluorescence (LIF) diagnostics were used to measure temporal variations of plasma parameters and the xenon ion velocity distribution function (IVDF) in the near-field plasma plume in regimes with moderate (reducing the production of metastable ions. Because the residence time of ions in the channel is generally shorter than the time scale of breathing oscillations, the density of the excited ions outside the thruster is low and they cannot be detected. In the range of temperature of oscillations, the ionization cross-section of xenon atoms remains sufficiently large to sustain the discharge. This finding suggests that the commonly used LIF diagnostic of xenon IVDF can be subject to large uncertainties in the regimes with significant oscillations of the electron temperature, or other plasma parameters.

  8. Framework agreements in public procurement

    DEFF Research Database (Denmark)

    Andrecka, Marta; Telles, Pedro


    Interview with Dr. Marta Andrecka, Postdoctoral Fellow at the Department of Law at the University of Aarhus, where she is currently working on a project called "Dealing with legal loopholes and uncertainties within EU public procurement law regarding framework agreements" sponsored by the Carlsberg...... Foundation. Before taking up her present position she carried out her doctoral research in Denmark and Australia and worked at law offices in both Poland and the UK. The topic for today’s talk is framework agreements, a relatively popular way of undertaking public procurement...

  9. Uranium ore purchase and custom milling agreements

    International Nuclear Information System (INIS)

    Dolan, B.T.


    Important considerations involved in structuring agreements for ore sale or other disposition are discussed. Payment provisions in ore purchase agreements and custom milling agreement provisions are considered. Proposed forms of Ore Purchase Agreement and Custom Milling Agreement are included as appendices

  10. 46 CFR Sec. 4 - Service agreements. (United States)


    ... Service agreements. Contract MA ___ Service Agreement, Federal Port Controller This agreement, made as of... compensation after the contract comes into force will be negotiated, if appropriate. Employee service expenses... secure this agreement upon any agreement for a commission, percentage, brokerage, or contingent fee...

  11. Between voluntary agreement and legislation

    DEFF Research Database (Denmark)

    Gwozdz, Wencke; Hedegaard, Liselotte; Reisch, Lucia


    Voluntary agreements and self-imposed standards are broadly applied to restrict the influence food advertising exerts on children’s food choices – yet their effects are unknown. The current project will therefore investigate whether and, if yes, how the Danish Code for Responsible Food Marketing...

  12. Governance of material transfer agreements

    NARCIS (Netherlands)

    Rodriguez, V.F.


    The governance of material transfer agreements (MTAs) is crucial for research and the progress of science. When developing a research project, researchers face the problem of availability of research material or restrictive provisions imposed by providers. This article discusses the governance of

  13. Form 6 - gas balancing agreement

    International Nuclear Information System (INIS)



    In 1988, a special Committee of the Rocky Mountain Mineral Law Foundation undertook a project to draft a model from gas balancing agreement. This project was initiated at the request of a number of Foundation members who felt that a model form gas balancing agreement would facilitate the negotiation of operating agreement, since gas balancing issues had become sticking points in the process. The Committee was composed of attorneys representing a wide cross-section of the oil and gas industry including both major and independent oil companies, production companies with interstate pipeline affiliates, and private practitioners. The Committee attempted to address the more controversial issues in gas balancing with optional provisions in the Form. To facilitate the negotiation process, the number of optional provisions was minimized. This form may be used as an Appendix to the new A.A.P.L. Form 610-1989 Model Form Operating Agreement. This book includes provision of this Form which are: Ownership of gas production; Balancing of production accounts; Cash balancing upon depletion; Deliverability tests; Nominations; Statements; Payment of taxes; Operating expenses; Overproducing allowable; Payment of leasehold burdens; Operator's liability; Successors and assigns; Audits; Arbitration; and Operator's fees

  14. Spin disorder effect in anomalous Hall effect in MnGa (United States)

    Mendonça, A. P. A.; Varalda, J.; Schreiner, W. H.; Mosca, D. H.


    We report on resistivity and Hall effect in MnGa thin films grown by molecular beam epitaxy on GaAs substrates. Highly (1 1 1)-textured MnGa film with L10 structure exhibits hard magnetic properties with coercivities as high as 20 kOe and spin disorder mechanisms contributing to the Hall conductivity at room temperature. Density functional theory calculations were performed to determine the intrinsic Berry curvature in the momentum space with chiral spin structure that results in an anomalous Hall conductivity of 127 (Ωcm)-1 comparable to that measured at low temperature. In addition to residual and side-jump contributions, which are enhanced by thermal activation, both anomalous Hall conductivity and Hall angle increase between 100 K and room temperature. The present results reinforce the potential of Mn-Ga system for developing Hall effect-based spintronic devices.

  15. Observer Variability and the Performance between Faculties and Residents: US Criteria for Benign and Malignant Thyroid Nodules

    International Nuclear Information System (INIS)

    Kim, Sung Hun; Park, Chang Suk; Jung, So Lyung


    To evaluate the interobserver variability and performance in the interpretation of ultrasonographic (US) findings of thyroid nodules. 72 malignant nodules and 61 benign nodules were enrolled as part of this study. Five faculty radiologists and four residents independently performed a retrospective analysis of the US images. The observers received one training session after the first interpretation and then performed a secondary interpretation. Agreement was analyzed by Cohen's kappa statistic. Degree of performance was analyzed using receiver operating characteristic (ROC) curves. Agreement between the faculties was fair-to-good for all criteria; however, between residents, agreement was poor-to-fair. The area under the ROC curves was 0.72, 0.62, and 0.60 for the faculties, senior residents, and junior residents, respectively. There was a significant difference in performance between the faculties and the residents (p < 0.05). There was a significant increase in the agreement for some criteria in the faculties and the senior residents after the training session, but no significant increase in the junior residents. Independent reporting of thyroid US performed by residents is undesirable. A continuous and specialized resident training is essential to enhance the degree of agreement and performance

  16. Theoretical calculation of the Hall mobility of InNxAs1− x alloys ...

    Indian Academy of Sciences (India)


    Nov 27, 2015 ... The Hall mobilities of InAs and InN0.01As0.99 are presented in the temperature range of 30–600 K. It is shown that incorporation of even small amount of nitrogen leads to an abrupt reduction of the Hall mobility in InNAs1− at low temperatures. The effect of alloy random scattering on the Hall mobility of ...

  17. Magnetoresistivity and Hall resistivity of a YBCO thin film in a tilted magnetic field

    International Nuclear Information System (INIS)

    Amirfeiz, M.; Cimberle, M. R.; Ferdeghini, C.; Giannini, E.; Grassano, G.; Marre', D.; Putti, M.; Siri, A. S.


    In this paper they present magnetoresistivity and Hall effect measurements performed on a YBCO epitaxial film as a function of the angle θ between the external magnetic field and the a-b planes. The resistivity and Hall effect measurements are analyzed in term of the general scaling approach proposed by Blatter and coworkers; the Hall conductivity data are examined to separate the contributions due to vortices and quasi particles

  18. Field-tuned superconductor–insulator transitions and Hall resistance in thin polycrystalline MoN films (United States)

    Makise, Kazumasa; Ichikawa, Fusao; Asano, Takayuki; Shinozaki, Bunju


    We report on the superconductor–insulator transitions (SITs) of disordered molybdenum nitride (MoN) thin films on (1 0 0) MgO substrates as a function of the film thickness and magnetic fields. The T c of the superconducting MoN films, which exhibit a sharp superconducting transition, monotonically decreases as the normal state R sq increases with a decreasing film thickness. For several films with different thicknesses, we estimate the critical field H c and the product zν  ≃  0.6 of the dynamical exponent z and the correlation length exponent ν using a finite scaling analysis. The value of this product can be explained by the (2  +  1) XY model. We found that the Hall resistance ΔR xy (H) is maximized when the magnetic field satisfies H HP(T) \\propto |1  ‑  T/T C0| in the superconducting state and also in the normal states owning to the superconducting fluctuation corresponding to the ghost critical magnetic field. We measured the Hall conductivity δσ xy (H)  =  σ xy (H)  ‑  σ xyn and fit the Gaussian approximation theory for δσ xy (H) to the experimental data. Agreement between the data and the theory beyond H c suggests the survival of the Cooper pair in the insulating region of the SIT.

  19. 76 FR 20668 - Notice of Agreements Filed (United States)


    ... Agreement. Agreement No.: 012105-001. Title: SCM Lines Transportes/CCNI Agreement. Parties: Compania Chilena de Navegacion Interoceanica S.A. and SCM Lines Transportes Maritimos Sociedade Unipessoal, LDA...

  20. 76 FR 16420 - Notice of Agreements Filed (United States)


    .... Title: Hanjin and WHS Transpacific Vessel Sharing and Slot Allocation Agreement. Parties: Hanjin... amendment would add COSCON as a party to the Agreement and revise the name of the Agreement to Hanjin/WHS...

  1. 78 FR 35270 - Notice of Agreements Filed (United States)


    ... Russia from the geographic scope of the agreement. Agreement No.: 012210. Title: Siem Car Carrier Pacific AS/Eukor Car Carriers Inc. Space Charter Agreement. Parties: Siem Car Carrier Pacific AS and Eukor...

  2. Wendelstein 7-X Torus Hall Layout and System Integration

    International Nuclear Information System (INIS)

    Hartmann, D.; Damiani, C.; Hartfuss, H.-J.; Krampitz, R.; Neuner, U.


    Wendelstein 7-X is an experimental fusion device presently under construction in Greifswald, Germany, to study the stellarator concept at reactor relevant parameters und steady-state conditions. The heart of the machine consists of the torus that houses the superconducting coils and the plasma vacuum vessel. It is located nearly in the center of a 30 m x 30 m x 20 m hall. A large number of components need to be placed in close proximity of the torus to provide the system with the required means, e.g. cryogenic gases, cooling water, electricity, and to integrate it with the peripheral diagnostic and heating components. The arrangement of these components has to be supported by suitable structures, and has to be optimized to allow for installation, maintenance, and repair. In addition, space has to be provided for escape routes and for sufficient distance between components that could negatively influence each other's performance, etc. The layout of the components has been done over many years using 3D CAD software. It was based on simple geometric models of the components and of the additionally required space. Presently the layout design is being detailed and updated by replacing the original coarse models with more refined estimates or - in some cases - with as-built models. All interface requirements are carefully taken into account. Detailed routing was specified for the cryo and cooling water supply lines whose design and installation is outsourced. Due to the limited space available and severely restricted access during experimental campaigns, the requirement to put auxiliary components like electronic racks into the torus hall is being queried. The paper summarizes the present state of the component layout in the torus hall, and how the peripheral supply, diagnostics, and heating systems are integrated into the machine. (author)

  3. Low-Cost High-Performance Hall Thruster Support System, Phase II (United States)

    National Aeronautics and Space Administration — Colorado Power Electronics (CPE) has built an innovative modular power processing unit (PPU) for Hall Thrusters, including discharge, magnet, heater and keeper...

  4. Detection and Solution of Indoor Air Quality Problems in a Danish Town Hall

    DEFF Research Database (Denmark)

    Hyldgård, Carl-Erik; Brohus, Henrik

    In connection with the research programme "Healthy Buildings", a building with indoor air quality problems was selected for further investigations. A Danish town hall was chosen because of many complaints over several years. A full-scale mock-up of a typical town hall office was built in the clim......In connection with the research programme "Healthy Buildings", a building with indoor air quality problems was selected for further investigations. A Danish town hall was chosen because of many complaints over several years. A full-scale mock-up of a typical town hall office was built...

  5. Quantum Hall effect and hopping conductivity in n-InGaAs/InAlAs nanoheterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Gudina, S. V., E-mail:; Arapov, Yu. G.; Saveliev, A. P.; Neverov, V. N.; Podgornykh, S. M.; Shelushinina, N. G.; Yakunin, M. V. [Russian Academy of Sciences, Mikheev Institute of Metal Physics, Ural Branch (Russian Federation); Vasil’evskii, I. S.; Vinichenko, A. N. [National Research Nuclear University MEPhI (Russian Federation)


    The longitudinal and Hall magnetoresistances are measured in the quantum Hall effect regime in the n-InGaAs/InAlAs heterostructures at temperatures of T = (1.8–30) K in magnetic fields up to B = 9 T. Temperature-induced transport in the region of the longitudinal resistance minima, corresponding to the plateau regions at Hall resistance, is investigated within the framework of the concept of hopping conductivity in a strongly localized electron system. The analysis of variable-range hopping conductivity in the region of the second, third, and fourth plateau of the quantum Hall effect provides the possibility of determining the localization length exponent.

  6. Recent multi-purpose hall designs in Denmark with physically variable acoustics

    DEFF Research Database (Denmark)

    Gade, Anders Christian


    house. This hall is used for symphonic concerts and musicals as well as drama and conferences. In this hall, maintaining or even increasing G along with a reduction in T is advantageous, especially in the drama theatre mode. The paper will describe the design of these two halls along with acoustic...... and be used for chamber music concerts, symphony orchestra rehearsals, and amplified speech. For the latter two functions, a reduction in G along with reduction in T was considered favorable. The hall with variable volume is the recently opened Esbjerg Musikhus seating 1100 and equipped with a full stage...

  7. Long Life Miniature Hall Thruster Enabling Low Cost Human Precursor Missions (United States)

    National Aeronautics and Space Administration — Key and Central Objectives: This investigation aims to demonstrate that the application of magnetic shielding technology on miniature Hall thrusters will...

  8. Hall Plateaus at magic angles in ultraquantum Bismuth (United States)

    Benoît, Fauqué.


    The behaviour of a three-dimensional electron gas in the presence of a magnetic field strong enough to put all carriers in the first Landau level (i.e. beyond the quantum limit) is a longstanding question of theoretical condensed matter physics [1]. This issue has been recently explored by two high-field experiments on elemental semi-metal Bismuth. In a first study of transport coefficients (which are dominated by hole-like carriers), the Nernst coefficient presented three unexpected maxima that are concomitant with quasi-plateaux in the Hall coefficient [2]. In a second series of experiments, torque magnetometry (which mainly probes the three Dirac valley electron pockets) detected a field-induced phase transition [3]. The full understanding of the electron and hole behaviours above the quantum limit of pure Bi is therefore still under debate. In this talk, we will present our measurement of the Hall resistivity and torque magnetometry with magnetic field up to 31 T and rotating in the trigonal-bisectrix plane [4]. The Hall response is dominated by the hole pockets according to its sign as well as the period and the angular dependence of its quantum oscillations. In the vicinity of the quantum limit, it presents additional anomalies which are the fingerprints of the electron pockets. We found that for particular orientations of the magnetic field (namely ``magic angles''), the Hall response becomes field-independent within the experimental resolution around 20T. This drastic dependence of the plateaux on the field orientation provides strong constraints for theoretical scenarios. [4pt] [1] Bertrand I. Halperin, Japanese Journal of Applied Physics, 26, Supplement 26-3 (1987).[0pt] [2] Kamran Behnia, Luis Balicas, Yakov Kopelevich, Science, 317, 1729 (2008).[0pt] [3] Lu Li, J. G. Checkelsky, Y. S. Hor, C. Uher, A. F. Hebard, R. J. Cava, and N. P. Ong , Science, 321, 5888 (2008).[0pt] [4] Benoît Fauqu'e, Luis Balicas, Ilya Sheikin, Jean Paul Issi and Kamran Behnia

  9. Photoproduction of Light and Exotic Mesons in Hall D (United States)

    Meyer, Curtis


    The Jefferson Lab Hall D collaboration is proposing a program to search for and study gluonic excitations of mesons using 8-9 GeV linearly polarized photon beams. By extending the nearly non-existent meson data in photoproduction, as well as taking advantage of a spin 1 probe, we expect to be able to produce and study hybrid mesons with exotic, or non q-barq quantum numbers. The properties of these mesons yield information on the dynamic nature of gluons, and yield information on the issue of confinement.

  10. Controlling the Plasma Flow in the Miniaturized Cylindrical Hall Thruster

    International Nuclear Information System (INIS)

    Smirnov, A.; Raitses, Y.; Fisch, N.J.


    A substantial narrowing of the plume of the cylindrical Hall thruster (CHT) was observed upon the enhancement of the electron emission from the hollow cathode discharge, which implies the possibility for the thruster efficiency increase due to the ion beam focusing. It is demonstrated that the miniaturized CHT can be operated in the non-self-sustained regime, with the discharge current limited by the cathode electron emission. The thruster operation in this mode greatly expands the range of the plasma and discharge parameters normally accessible for the CHT.

  11. Frazier Hall: The foundation failure that didn't

    International Nuclear Information System (INIS)

    Robinson, L.


    Frazier Hall is the oldest building on the Idaho State University campus--built before scientific foundation design was common. Its footings were clearly under designed, compared with modern practice. In fact, conventional analysis of the bearing capacity of two footings of this historic building indicate a failure condition. However, this structure is 60 years old and the foundation is still functioning. Possible reasons for the discrepancy between the analysis results and reality are posed and evaluated. This exercise gives some valuable insights into the process of foundation analysis and design. 7 refs., 5 figs

  12. New approach for measuring the microwave Hall mobility of semiconductors

    International Nuclear Information System (INIS)

    Murthy, D. V. B.; Subramanian, V.; Murthy, V. R. K.


    Measurement of Hall mobility in semiconductor samples using bimodal cavity method gives distinct advantages due to noncontact nature as well as the provision to measure anisotropic mobility. But the measurement approaches followed till now have a disadvantage of having high error values primarily due to the problem in evaluating the calibration constant of the whole experimental arrangement. This article brings out a new approach that removes such disadvantage and presents the calibration constant with 1% accuracy. The overall error in the carrier mobility values is within 5%

  13. Numerical investigation of closed-loop control for Hall accelerators

    International Nuclear Information System (INIS)

    Barral, S.; Miedzik, J.


    Low frequency discharge current oscillations in Hall accelerators are conventionally damped with external inductor-capacitor (LC) or resistor-inductor-capacitor (RLC) networks. The role of such network in the stabilization of the plasma discharge is investigated with a numerical model and the potential advantages of proportional-integral-derivative (PID) closed-loop control over RLC networks are subsequently assessed using either discharge voltage or magnetic field modulation. Simulations confirm the reduction of current oscillations in the presence of a RLC network, but suggest that PID control could ensure nearly oscillation-free operation with little sensitivity toward the PID settings.

  14. Spin-injection Hall effect in a planar photovoltaic cell

    Czech Academy of Sciences Publication Activity Database

    Wunderlich, J.; Irvine, A.C.; Sinova, J.; Park, B.G.; Zarbo, L.P.; Xu, X.L.; Kaestner, B.; Novák, Vít; Jungwirth, Tomáš


    Roč. 5, č. 9 (2009), s. 675-681 ISSN 1745-2473 R&D Projects: GA MŠk LC510; GA AV ČR KAN400100652; GA ČR GEFON/06/E002; GA ČR GEFON/06/E001 EU Projects: European Commission(XE) 215368 - SemiSpinNet Grant - others:AV ČR(CZ) AP0801 Program:Akademická prémie - Praemium Academiae Institutional research plan: CEZ:AV0Z10100521 Keywords : extraordinary Hall effect s * spintronics * photvoltaics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 15.491, year: 2009

  15. Modeling large underground experimental halls for the superconducting super collider

    International Nuclear Information System (INIS)

    Duan, F.; Mrugala, M.


    Geomechanical aspects of the excavation design, and analysis of two large underground experimental halls for the Superconducting Super Collider (SSC), being built in Texas, have been extensively investigated using computer modeling. Each chamber, measuring approximately 350 ft long, 110 ft wide, and 190 ft high, is to be excavated mainly through soft marl and overlying competent limestone. Wall stability is essential not only for ensuring excavation safety but also for meeting strict requirements for chamber stability over the 30-yr design life of the facility. Extensive numerical modeling has played a significant role in the selection of excavation methods, excavation sequence, and rock reinforcement systems. (Author)

  16. TOPICAL REVIEW: Spin current, spin accumulation and spin Hall effect

    Directory of Open Access Journals (Sweden)

    Saburo Takahashi and Sadamichi Maekawa


    Full Text Available Nonlocal spin transport in nanostructured devices with ferromagnetic injector (F1 and detector (F2 electrodes connected to a normal conductor (N is studied. We reveal how the spin transport depends on interface resistance, electrode resistance, spin polarization and spin diffusion length, and obtain the conditions for efficient spin injection, spin accumulation and spin current in the device. It is demonstrated that the spin Hall effect is caused by spin–orbit scattering in nonmagnetic conductors and gives rise to the conversion between spin and charge currents in a nonlocal device. A method of evaluating spin–orbit coupling in nonmagnetic metals is proposed.

  17. Scalar spin chirality and quantum hall effect on triangular lattices

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Ivar [Los Alamos National Laboratory; Batista, Cristian D [Los Alamos National Laboratory


    We study the Kondo Lattice and Hubbard models on a triangular lattice for band filling factor 3/4. We show that a simple non-coplanar chiral spin ordering (scalar spin chirality) is naturally realized in both models due to perfect nesting of the fermi surface. The resulting triple-Q magnetic ordering is a natural counterpart of the collinear Neel ordering of the half-filled square lattice Hubbard model. We show that the obtained chiral phase exhibits a spontaneous quantum Hall-effect with {sigma}{sub xy} = e{sup 2}/h.

  18. Shielding evaluation of neutron generator hall by Monte Carlo simulations

    Energy Technology Data Exchange (ETDEWEB)

    Pujala, U.; Selvakumaran, T.S.; Baskaran, R.; Venkatraman, B. [Radiological Safety Division, Indira Gandhi Center for Atomic Research, Kalpakkam (India); Thilagam, L.; Mohapatra, D.K., E-mail: [Safety Research Institute, Atomic Energy Regulatory Board, Kalpakkam (India)


    A shielded hall was constructed for accommodating a D-D, D-T or D-Be based pulsed neutron generator (NG) with 4π yield of 10{sup 9} n/s. The neutron shield design of the facility was optimized using NCRP-51 methodology such that the total dose rates outside the hall areas are well below the regulatory limit for full occupancy criterion (1 μSv/h). However, the total dose rates at roof top, cooling room trench exit and labyrinth exit were found to be above this limit for the optimized design. Hence, additional neutron shielding arrangements were proposed for cooling room trench and labyrinth exits. The roof top was made inaccessible. The present study is an attempt to evaluate the neutron and associated capture gamma transport through the bulk shields for the complete geometry and materials of the NG-Hall using Monte Carlo (MC) codes MCNP and FLUKA. The neutron source terms of D-D, D-T and D-Be reactions are considered in the simulations. The effect of additional shielding proposed has been demonstrated through the simulations carried out with the consideration of the additional shielding for D-Be neutron source term. The results MC simulations using two different codes are found to be consistent with each other for neutron dose rate estimates. However, deviation up to 28% is noted between these two codes at few locations for capture gamma dose rate estimates. Overall, the dose rates estimated by MC simulations including additional shields shows that all the locations surrounding the hall satisfy the full occupancy criteria for all three types of sources. Additionally, the dose rates due to direct transmission of primary neutrons estimated by FLUKA are compared with the values calculated using the formula given in NCRP-51 which shows deviations up to 50% with each other. The details of MC simulations and NCRP-51 methodology for the estimation of primary neutron dose rate along with the results are presented in this paper. (author)

  19. International agreements on nuclear weapons

    International Nuclear Information System (INIS)

    Dombey, N.


    The satellite detection of a nuclear explosion in the South Atlantic and Israel's destruction of a research reactor in Iraq make it essential to strengthen existing monitoring and enforcement programs to prevent proliferation. While there was no reliable evidence that either South Africa or Iraq was violating non-proliferation agreements, worst case scenarios can demonstrate to unfriendly countries that South Africa had diverted fuel to test a nuclear weapon and that Iraq is intending to produce weapons-grade plutonium 239. The situation can be improved by formulating better terms and conditions for internationalizing access to materials. Nuclear suppliers need to agree on terms that will assure their customers that contracts for civil programs will be honored. The International Atomic Energy Agency (IAEA), which includes both nuclear suppliers and customers, could achieve stronger agreements that take into account recent technological advances that will expand enrichment and reprocessing activities. 23 references, 1 figure

  20. Fractional Quantum Hall Effects in Graphene on a h-BN Substrate (United States)

    Yonaga, Kouki; Shibata, Naokazu


    Fractional quantum Hall (FQH) effects in graphene are studied because of their relativistic characteristics and the valley degree of freedom. Recently FQH effects have been observed at various filling factors with graphene on a hexagonal boron nitride (h-BN) substrate. However, it is known that h-BN creates the mass term in the Dirac Hamiltonian that acts as the effective model of graphene. To understand recent experiments, we shall investigate many-body effects in the massive Dirac electron system. In this paper, we study the mass-term effects on the FQH states of Dirac electrons by exact diagonalization. We examine the ground state at filling factor 1/3 in the n = ±1 Landau level. Without the mass term, the ground state in the Laughlin state featuring valley degeneracy and the lowest excitation is characterized by the valley unpolarized state (known as the valley skyrmion state). Conversely, we find that the mass-term lifts the valley degeneracy due to the breaking of the inversion symmetry. We also demonstrate that the valley unpolarized excitation is suppressed and that the fully or partially polarized state appears in the lowest excitation by increasing the mass term. Finally, we discuss the stability of FQH states in the massive Dirac Hamiltonian in experimental situations. We find that our numerical results are in agreement with previous experimental results.